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Copyright © 2011 Bdale Garbee and Keith Packard
- This document is released under the terms of the - - Creative Commons ShareAlike 3.0 - - license. -
Revision History | |
---|---|
Revision 1.0 | 24 August 2011 |
- Updated for software version 1.0. Note that 1.0 represents a - telemetry format change, meaning both ends of a link - (TeleMetrum/TeleMini and TeleDongle) must be updated or - communications will fail. - | |
Revision 0.9 | 18 January 2011 |
- Updated for software version 0.9. Note that 0.9 represents a - telemetry format change, meaning both ends of a link (TeleMetrum and - TeleDongle) must be updated or communications will fail. - | |
Revision 0.8 | 24 November 2010 |
Updated for software version 0.8 |
- Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing "The - Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter - Kit" which formed the basis of the original Getting Started chapter - in this manual. Bob was one of our first customers for a production - TeleMetrum, and his continued enthusiasm and contributions - are immensely gratifying and highly appreciated! -
-- And thanks to Anthony (AJ) Towns for major contributions including - the AltosUI graphing and site map code and associated documentation. - Free software means that our customers and friends can become our - collaborators, and we certainly appreciate this level of - contribution! -
-- Have fun using these products, and we hope to meet all of you - out on the rocket flight line somewhere. -
-Bdale Garbee, KB0G
-NAR #87103, TRA #12201
-
-Keith Packard, KD7SQG
-NAR #88757, TRA #12200
-
-
-Table of Contents
- Welcome to the Altus Metrum community! Our circuits and software reflect - our passion for both hobby rocketry and Free Software. We hope their - capabilities and performance will delight you in every way, but by - releasing all of our hardware and software designs under open licenses, - we also hope to empower you to take as active a role in our collective - future as you wish! -
- The first device created for our community was TeleMetrum, a dual - deploy altimeter with fully integrated GPS and radio telemetry - as standard features, and a "companion interface" that will - support optional capabilities in the future. -
- The newest device is TeleMini, a dual deploy altimeter with - radio telemetry and radio direction finding. This device is only - 13mm by 38mm (½ inch by 1½ inches) and can fit easily in an 18mm - air-frame. -
- Complementing TeleMetrum and TeleMini is TeleDongle, a USB to RF - interface for communicating with the altimeters. Combined with your - choice of antenna and - notebook computer, TeleDongle and our associated user interface software - form a complete ground station capable of logging and displaying in-flight - telemetry, aiding rocket recovery, then processing and archiving flight - data for analysis and review. -
- More products will be added to the Altus Metrum family over time, and - we currently envision that this will be a single, comprehensive manual - for the entire product family. -
- The first thing to do after you check the inventory of parts in your - "starter kit" is to charge the battery. -
- The TeleMetrum battery can be charged by plugging it into the - corresponding socket of the TeleMetrum and then using the USB A to - mini B - cable to plug the TeleMetrum into your computer's USB socket. The - TeleMetrum circuitry will charge the battery whenever it is plugged - in, because the TeleMetrum's on-off switch does NOT control the - charging circuitry. -
- When the GPS chip is initially searching for - satellites, TeleMetrum will consume more current than it can pull - from the USB port, so the battery must be attached in order to get - satellite lock. Once GPS is locked, the current consumption goes back - down enough to enable charging while - running. So it's a good idea to fully charge the battery as your - first item of business so there is no issue getting and maintaining - satellite lock. The yellow charge indicator led will go out when the - battery is nearly full and the charger goes to trickle charge. It - can take several hours to fully recharge a deeply discharged battery. -
- The TeleMini battery can be charged by disconnecting it from the - TeleMini board and plugging it into a standalone battery charger - board, and connecting that via a USB cable to a laptop or other USB - power source -
- The other active device in the starter kit is the TeleDongle USB to - RF interface. If you plug it in to your Mac or Linux computer it should - "just work", showing up as a serial port device. Windows systems need - driver information that is part of the AltOS download to know that the - existing USB modem driver will work. We therefore recommend installing - our software before plugging in TeleDongle if you are using a Windows - computer. If you are using Linux and are having problems, try moving - to a fresher kernel (2.6.33 or newer), as the USB serial driver had - ugly bugs in some earlier versions. -
- Next you should obtain and install the AltOS software. These include - the AltosUI ground station program, current firmware images for - TeleMetrum, TeleMini and TeleDongle, and a number of standalone - utilities that are rarely needed. Pre-built binary packages are - available for Linux, Microsoft Windows, and recent MacOSX versions. - Full source code and build instructions are also available. - The latest version may always be downloaded from - http://altusmetrum.org/AltOS. -
- All Altus Metrum products are sophisticated electronic devices. - When handled gently and properly installed in an air-frame, they - will deliver impressive results. However, as with all electronic - devices, there are some precautions you must take. -
- The Lithium Polymer rechargeable batteries have an - extraordinary power density. This is great because we can fly with - much less battery mass than if we used alkaline batteries or previous - generation rechargeable batteries... but if they are punctured - or their leads are allowed to short, they can and will release their - energy very rapidly! - Thus we recommend that you take some care when handling our batteries - and consider giving them some extra protection in your air-frame. We - often wrap them in suitable scraps of closed-cell packing foam before - strapping them down, for example. -
- The barometric sensors used on both TeleMetrum and TeleMini are - sensitive to sunlight. In normal TeleMetrum mounting situations, it - and all of the other surface mount components - are "down" towards whatever the underlying mounting surface is, so - this is not normally a problem. Please consider this, though, when - designing an installation, for example, in an air-frame with a - see-through plastic payload bay. It is particularly important to - consider this with TeleMini, both because the baro sensor is on the - "top" of the board, and because many model rockets with payload bays - use clear plastic for the payload bay! Replacing these with an opaque - cardboard tube, painting them, or wrapping them with a layer of masking - tape are all reasonable approaches to keep the sensor out of direct - sunlight. -
- The barometric sensor sampling port must be able to "breathe", - both by not being covered by foam or tape or other materials that might - directly block the hole on the top of the sensor, and also by having a - suitable static vent to outside air. -
- As with all other rocketry electronics, Altus Metrum altimeters must - be protected from exposure to corrosive motor exhaust and ejection - charge gasses. -
- TeleMetrum is a 1 inch by 2.75 inch circuit board. It was designed to - fit inside coupler for 29mm air-frame tubing, but using it in a tube that - small in diameter may require some creativity in mounting and wiring - to succeed! The presence of an accelerometer means TeleMetrum should - be aligned along the flight axis of the airframe, and by default the 1/4 - wave UHF wire antenna should be on the nose-cone end of the board. The - antenna wire is about 7 inches long, and wiring for a power switch and - the e-matches for apogee and main ejection charges depart from the - fin can end of the board, meaning an ideal "simple" avionics - bay for TeleMetrum should have at least 10 inches of interior length. -
- TeleMini is a 0.5 inch by 1.5 inch circuit board. It was designed to - fit inside an 18mm air-frame tube, but using it in a tube that - small in diameter may require some creativity in mounting and wiring - to succeed! Since there is no accelerometer, TeleMini can be mounted - in any convenient orientation. The default 1/4 - wave UHF wire antenna attached to the center of one end of - the board is about 7 inches long, and wiring for a power switch and - the e-matches for apogee and main ejection charges depart from the - other end of the board, meaning an ideal "simple" avionics - bay for TeleMini should have at least 9 inches of interior length. -
- A typical TeleMetrum or TeleMini installation involves attaching - only a suitable Lithium Polymer battery, a single pole switch for - power on/off, and two pairs of wires connecting e-matches for the - apogee and main ejection charges. All Altus Metrum products are - designed for use with single-cell batteries with 3.7 volts nominal. -
- By default, we use the unregulated output of the Li-Po battery directly - to fire ejection charges. This works marvelously with standard - low-current e-matches like the J-Tek from MJG Technologies, and with - Quest Q2G2 igniters. However, if you want or need to use a separate - pyro battery, check out the "External Pyro Battery" section in this - manual for instructions on how to wire that up. The altimeters are - designed to work with an external pyro battery of no more than 15 volts. -
- Ejection charges are wired directly to the screw terminal block - at the aft end of the altimeter. You'll need a very small straight - blade screwdriver for these screws, such as you might find in a - jeweler's screwdriver set. -
- TeleMetrum also uses the screw terminal block for the power - switch leads. On TeleMini, the power switch leads are soldered - directly to the board and can be connected directly to a switch. -
- For most air-frames, the integrated antennas are more than - adequate. However, if you are installing in a carbon-fiber or - metal electronics bay which is opaque to RF signals, you may need to - use off-board external antennas instead. In this case, you can - order an altimeter with an SMA connector for the UHF antenna - connection, and, on TeleMetrum, you can unplug the integrated GPS - antenna and select an appropriate off-board GPS antenna with - cable terminating in a U.FL connector. -
Table of Contents
- The AltOS firmware build for the altimeters has two - fundamental modes, "idle" and "flight". Which of these modes - the firmware operates in is determined at start up time. For - TeleMetrum, the mode is controlled by the orientation of the - rocket (well, actually the board, of course...) at the time - power is switched on. If the rocket is "nose up", then - TeleMetrum assumes it's on a rail or rod being prepared for - launch, so the firmware chooses flight mode. However, if the - rocket is more or less horizontal, the firmware instead enters - idle mode. Since TeleMini doesn't have an accelerometer we can - use to determine orientation, "idle" mode is selected when the - board receives a command packet within the first five seconds - of operation; if no packet is received, the board enters - "flight" mode. -
- At power on, you will hear three beeps or see three flashes - ("S" in Morse code for start up) and then a pause while - the altimeter completes initialization and self test, and decides - which mode to enter next. -
- In flight or "pad" mode, the altimeter engages the flight - state machine, goes into transmit-only mode to - send telemetry, and waits for launch to be detected. - Flight mode is indicated by an "di-dah-dah-dit" ("P" for pad) - on the beeper or lights, followed by beeps or flashes - indicating the state of the pyrotechnic igniter continuity. - One beep/flash indicates apogee continuity, two beeps/flashes - indicate main continuity, three beeps/flashes indicate both - apogee and main continuity, and one longer "brap" sound or - rapidly alternating lights indicates no continuity. For a - dual deploy flight, make sure you're getting three beeps or - flashes before launching! For apogee-only or motor eject - flights, do what makes sense. -
- If idle mode is entered, you will hear an audible "di-dit" or see - two short flashes ("I" for idle), and the flight state machine is - disengaged, thus no ejection charges will fire. The altimeters also - listen for the radio link when in idle mode for requests sent via - TeleDongle. Commands can be issued to a TeleMetrum in idle mode - over either - USB or the radio link equivalently. TeleMini only has the radio link. - Idle mode is useful for configuring the altimeter, for extracting data - from the on-board storage chip after flight, and for ground testing - pyro charges. -
- One "neat trick" of particular value when TeleMetrum is used with - very large air-frames, is that you can power the board up while the - rocket is horizontal, such that it comes up in idle mode. Then you can - raise the air-frame to launch position, and issue a 'reset' command - via TeleDongle over the radio link to cause the altimeter to reboot and - come up in flight mode. This is much safer than standing on the top - step of a rickety step-ladder or hanging off the side of a launch - tower with a screw-driver trying to turn on your avionics before - installing igniters! -
- TeleMetrum includes a complete GPS receiver. A complete explanation - of how GPS works is beyond the scope of this manual, but the bottom - line is that the TeleMetrum GPS receiver needs to lock onto at least - four satellites to obtain a solid 3 dimensional position fix and know - what time it is. -
- TeleMetrum provides backup power to the GPS chip any time a - battery is connected. This allows the receiver to "warm start" on - the launch rail much faster than if every power-on were a GPS - "cold start". In typical operations, powering up TeleMetrum - on the flight line in idle mode while performing final air-frame - preparation will be sufficient to allow the GPS receiver to cold - start and acquire lock. Then the board can be powered down during - RSO review and installation on a launch rod or rail. When the board - is turned back on, the GPS system should lock very quickly, typically - long before igniter installation and return to the flight line are - complete. -
- One of the unique features of the Altus Metrum system is - the ability to create a two way command link between TeleDongle - and an altimeter using the digital radio transceivers built into - each device. This allows you to interact with the altimeter from - afar, as if it were directly connected to the computer. -
- Any operation which can be performed with TeleMetrum can - either be done with TeleMetrum directly connected to the - computer via the USB cable, or through the radio - link. TeleMini doesn't provide a USB connector and so it is - always communicated with over radio. Select the appropriate - TeleDongle device when the list of devices is presented and - AltosUI will interact with an altimeter over the radio link. -
- One oddity in the current interface is how AltosUI selects the - frequency for radio communications. Instead of providing - an interface to specifically configure the frequency, it uses - whatever frequency was most recently selected for the target - TeleDongle device in Monitor Flight mode. If you haven't ever - used that mode with the TeleDongle in question, select the - Monitor Flight button from the top level UI, and pick the - appropriate TeleDongle device. Once the flight monitoring - window is open, select the desired frequency and then close it - down again. All radio communications will now use that frequency. -
- Save Flight Data—Recover flight data from the rocket without - opening it up. -
- Configure altimeter apogee delays or main deploy heights - to respond to changing launch conditions. You can also - 'reboot' the altimeter. Use this to remotely enable the - flight computer by turning TeleMetrum on in "idle" mode, - then once the air-frame is oriented for launch, you can - reboot the altimeter and have it restart in pad mode - without having to climb the scary ladder. -
- Fire Igniters—Test your deployment charges without snaking - wires out through holes in the air-frame. Simply assembly the - rocket as if for flight with the apogee and main charges - loaded, then remotely command the altimeter to fire the - igniters. -
- Operation over the radio link for configuring an altimeter, ground - testing igniters, and so forth uses the same RF frequencies as flight - telemetry. To configure the desired TeleDongle frequency, select - the monitor flight tab, then use the frequency selector and - close the window before performing other desired radio operations. -
- TeleMetrum only enables radio commanding in 'idle' mode, so - make sure you have TeleMetrum lying horizontally when you turn - it on. Otherwise, TeleMetrum will start in 'pad' mode ready for - flight, and will not be listening for command packets from TeleDongle. -
- TeleMini listens for a command packet for five seconds after - first being turned on, if it doesn't hear anything, it enters - 'pad' mode, ready for flight and will no longer listen for - command packets. The easiest way to connect to TeleMini is to - initiate the command and select the TeleDongle device. At this - point, the TeleDongle will be attempting to communicate with - the TeleMini. Now turn TeleMini on, and it should immediately - start communicating with the TeleDongle and the desired - operation can be performed. -
- You can monitor the operation of the radio link by watching the - lights on the devices. The red LED will flash each time a packet - is tramsitted, while the green LED will light up on TeleDongle when - it is waiting to receive a packet from the altimeter. -
- An important aspect of preparing a rocket using electronic deployment - for flight is ground testing the recovery system. Thanks - to the bi-directional radio link central to the Altus Metrum system, - this can be accomplished in a TeleMetrum or TeleMini equipped rocket - with less work than you may be accustomed to with other systems. It - can even be fun! -
- Just prep the rocket for flight, then power up the altimeter - in "idle" mode (placing air-frame horizontal for TeleMetrum or - selected the Configure Altimeter tab for TeleMini). This will cause - the firmware to go into "idle" mode, in which the normal flight - state machine is disabled and charges will not fire without - manual command. You can now command the altimeter to fire the apogee - or main charges from a safe distance using your computer and - TeleDongle and the Fire Igniter tab to complete ejection testing. -
- The chip our boards are based on incorporates an RF transceiver, but - it's not a full duplex system... each end can only be transmitting or - receiving at any given moment. So we had to decide how to manage the - link. -
- By design, the altimeter firmware listens for the radio link when - it's in "idle mode", which - allows us to use the radio link to configure the rocket, do things like - ejection tests, and extract data after a flight without having to - crack open the air-frame. However, when the board is in "flight - mode", the altimeter only - transmits and doesn't listen at all. That's because we want to put - ultimate priority on event detection and getting telemetry out of - the rocket through - the radio in case the rocket crashes and we aren't able to extract - data later... -
- We don't use a 'normal packet radio' mode like APRS because they're - just too inefficient. The GFSK modulation we use is FSK with the - base-band pulses passed through a - Gaussian filter before they go into the modulator to limit the - transmitted bandwidth. When combined with the hardware forward error - correction support in the cc1111 chip, this allows us to have a very - robust 38.4 kilobit data link with only 10 milliwatts of transmit - power, a whip antenna in the rocket, and a hand-held Yagi on the - ground. We've had flights to above 21k feet AGL with great reception, - and calculations suggest we should be good to well over 40k feet AGL - with a 5-element yagi on the ground. We hope to fly boards to higher - altitudes over time, and would of course appreciate customer feedback - on performance in higher altitude flights! -
- Configuring an Altus Metrum altimeter for flight is very - simple. Even on our baro-only TeleMini board, the use of a Kalman - filter means there is no need to set a "mach delay". The few - configurable parameters can all be set using AltosUI over USB or - or radio link via TeleDongle. -
- Altus Metrum boards support radio frequencies in the 70cm - band. By default, the configuration interface provides a - list of 10 "standard" frequencies in 100kHz channels starting at - 434.550MHz. However, the firmware supports use of - any 50kHz multiple within the 70cm band. At any given - launch, we highly recommend coordinating when and by whom each - frequency will be used to avoid interference. And of course, both - altimeter and TeleDongle must be configured to the same - frequency to successfully communicate with each other. -
- Apogee delay is the number of seconds after the altimeter detects flight - apogee that the drogue charge should be fired. In most cases, this - should be left at the default of 0. However, if you are flying - redundant electronics such as for an L3 certification, you may wish - to set one of your altimeters to a positive delay so that both - primary and backup pyrotechnic charges do not fire simultaneously. -
- The Altus Metrum apogee detection algorithm fires exactly at - apogee. If you are also flying an altimeter like the - PerfectFlite MAWD, which only supports selecting 0 or 1 - seconds of apogee delay, you may wish to set the MAWD to 0 - seconds delay and set the TeleMetrum to fire your backup 2 - or 3 seconds later to avoid any chance of both charges - firing simultaneously. We've flown several air-frames this - way quite happily, including Keith's successful L3 cert. -
- By default, the altimeter will fire the main deployment charge at an - elevation of 250 meters (about 820 feet) above ground. We think this - is a good elevation for most air-frames, but feel free to change this - to suit. In particular, if you are flying two altimeters, you may - wish to set the - deployment elevation for the backup altimeter to be something lower - than the primary so that both pyrotechnic charges don't fire - simultaneously. -
- TeleMetrum version 1.1 and 1.2 have 2MB of on-board flash storage, - enough to hold over 40 minutes of data at full data rate - (100 samples/second). TeleMetrum 1.0 has 1MB of on-board - storage. As data are stored at a reduced rate during descent - (10 samples/second), there's plenty of space to store many - flights worth of data. -
- The on-board flash is partitioned into separate flight logs, - each of a fixed maximum size. Increase the maximum size of - each log and you reduce the number of flights that can be - stored. Decrease the size and TeleMetrum can store more - flights. -
- All of the configuration data is also stored in the flash - memory, which consumes 64kB on TeleMetrum v1.1/v1.2 and 256B on - TeleMetrum v1.0. This configuration space is not available - for storing flight log data. -
- To compute the amount of space needed for a single flight, - you can multiply the expected ascent time (in seconds) by - 800, multiply the expected descent time (in seconds) by 80 - and add the two together. That will slightly under-estimate - the storage (in bytes) needed for the flight. For instance, - a flight spending 20 seconds in ascent and 150 seconds in - descent will take about (20 * 800) + (150 * 80) = 28000 - bytes of storage. You could store dozens of these flights in - the on-board flash. -
- The default size, 192kB, allows for 10 flights of storage on - TeleMetrum v1.1/v1.2 and 5 flights on TeleMetrum v1.0. This - ensures that you won't need to erase the memory before - flying each time while still allowing more than sufficient - storage for each flight. -
- As TeleMini does not contain an accelerometer, it stores - data at 10 samples per second during ascent and one sample - per second during descent. Each sample is a two byte reading - from the barometer. These are stored in 5kB of - on-chip flash memory which can hold 256 seconds at the - ascent rate or 2560 seconds at the descent rate. Because of - the limited storage, TeleMini cannot hold data for more than - one flight, and so must be erased after each flight or it - will not capture data for subsequent flights. -
- Instead of firing one charge at apogee and another charge at - a fixed height above the ground, you can configure the - altimeter to fire both at apogee or both during - descent. This was added to support an airframe that has two - TeleMetrum computers, one in the fin can and one in the - nose. -
- Providing the ability to use both igniters for apogee or - main allows some level of redundancy without needing two - flight computers. In Redundant Apogee or Redundant Main - mode, the two charges will be fired two seconds apart. -
- TeleMetrum measures acceleration along the axis of the - board. Which way the board is oriented affects the sign of - the acceleration value. Instead of trying to guess which way - the board is mounted in the air frame, TeleMetrum must be - explicitly configured for either Antenna Up or Antenna - Down. The default, Antenna Up, expects the end of the - TeleMetrum board connected to the 70cm antenna to be nearest - the nose of the rocket, with the end containing the screw - terminals nearest the tail. -
Table of Contents
- The AltosUI program provides a graphical user interface for - interacting with the Altus Metrum product family, including - TeleMetrum, TeleMini and TeleDongle. AltosUI can monitor telemetry data, - configure TeleMetrum, TeleMini and TeleDongle devices and many other - tasks. The primary interface window provides a selection of - buttons, one for each major activity in the system. This manual - is split into chapters, each of which documents one of the tasks - provided from the top-level toolbar. -
- Selecting this item brings up a dialog box listing all of the - connected TeleDongle devices. When you choose one of these, - AltosUI will create a window to display telemetry data as - received by the selected TeleDongle device. -
- All telemetry data received are automatically recorded in - suitable log files. The name of the files includes the current - date and rocket serial and flight numbers. -
- The radio frequency being monitored by the TeleDongle device is - displayed at the top of the window. You can configure the - frequency by clicking on the frequency box and selecting the desired - frequency. AltosUI remembers the last frequency selected for each - TeleDongle and selects that automatically the next time you use - that device. -
- Below the TeleDongle frequency selector, the window contains a few - significant pieces of information about the altimeter providing - the telemetry data stream: -
The configured call-sign
The device serial number
The flight number. Each altimeter remembers how many - times it has flown. -
- The rocket flight state. Each flight passes through several - states including Pad, Boost, Fast, Coast, Drogue, Main and - Landed. -
- The Received Signal Strength Indicator value. This lets - you know how strong a signal TeleDongle is receiving. The - radio inside TeleDongle operates down to about -99dBm; - weaker signals may not be receivable. The packet link uses - error detection and correction techniques which prevent - incorrect data from being reported. -
- Finally, the largest portion of the window contains a set of - tabs, each of which contain some information about the rocket. - They're arranged in 'flight order' so that as the flight - progresses, the selected tab automatically switches to display - data relevant to the current state of the flight. You can select - other tabs at any time. The final 'table' tab displays all of - the raw telemetry values in one place in a spreadsheet-like format. -
- The 'Launch Pad' tab shows information used to decide when the - rocket is ready for flight. The first elements include red/green - indicators, if any of these is red, you'll want to evaluate - whether the rocket is ready to launch: -
- Battery Voltage. This indicates whether the Li-Po battery - powering the TeleMetrum has sufficient charge to last for - the duration of the flight. A value of more than - 3.7V is required for a 'GO' status. -
- Apogee Igniter Voltage. This indicates whether the apogee - igniter has continuity. If the igniter has a low - resistance, then the voltage measured here will be close - to the Li-Po battery voltage. A value greater than 3.2V is - required for a 'GO' status. -
- Main Igniter Voltage. This indicates whether the main - igniter has continuity. If the igniter has a low - resistance, then the voltage measured here will be close - to the Li-Po battery voltage. A value greater than 3.2V is - required for a 'GO' status. -
- On-board Data Logging. This indicates whether there is - space remaining on-board to store flight data for the - upcoming flight. If you've downloaded data, but failed - to erase flights, there may not be any space - left. TeleMetrum can store multiple flights, depending - on the configured maximum flight log size. TeleMini - stores only a single flight, so it will need to be - downloaded and erased after each flight to capture - data. This only affects on-board flight logging; the - altimeter will still transmit telemetry and fire - ejection charges at the proper times. -
- GPS Locked. For a TeleMetrum device, this indicates whether the GPS receiver is - currently able to compute position information. GPS requires - at least 4 satellites to compute an accurate position. -
- GPS Ready. For a TeleMetrum device, this indicates whether GPS has reported at least - 10 consecutive positions without losing lock. This ensures - that the GPS receiver has reliable reception from the - satellites. -
-
- The Launchpad tab also shows the computed launch pad position - and altitude, averaging many reported positions to improve the - accuracy of the fix. -
-
- This tab is shown during Boost, Fast and Coast - phases. The information displayed here helps monitor the - rocket as it heads towards apogee. -
- The height, speed and acceleration are shown along with the - maximum values for each of them. This allows you to quickly - answer the most commonly asked questions you'll hear during - flight. -
- The current latitude and longitude reported by the TeleMetrum GPS are - also shown. Note that under high acceleration, these values - may not get updated as the GPS receiver loses position - fix. Once the rocket starts coasting, the receiver should - start reporting position again. -
- Finally, the current igniter voltages are reported as in the - Launch Pad tab. This can help diagnose deployment failures - caused by wiring which comes loose under high acceleration. -
- Once the rocket has reached apogee and (we hope) activated the - apogee charge, attention switches to tracking the rocket on - the way back to the ground, and for dual-deploy flights, - waiting for the main charge to fire. -
- To monitor whether the apogee charge operated correctly, the - current descent rate is reported along with the current - height. Good descent rates vary based on the choice of recovery - components, but generally range from 15-30m/s on drogue and should - be below 10m/s when under the main parachute in a dual-deploy flight. -
- For TeleMetrum altimeters, you can locate the rocket in the sky - using the elevation and - bearing information to figure out where to look. Elevation is - in degrees above the horizon. Bearing is reported in degrees - relative to true north. Range can help figure out how big the - rocket will appear. Note that all of these values are relative - to the pad location. If the elevation is near 90°, the rocket - is over the pad, not over you. -
- Finally, the igniter voltages are reported in this tab as - well, both to monitor the main charge as well as to see what - the status of the apogee charge is. Note that some commercial - e-matches are designed to retain continuity even after being - fired, and will continue to show as green or return from red to - green after firing. -
- Once the rocket is on the ground, attention switches to - recovery. While the radio signal is often lost once the - rocket is on the ground, the last reported GPS position is - generally within a short distance of the actual landing location. -
- The last reported GPS position is reported both by - latitude and longitude as well as a bearing and distance from - the launch pad. The distance should give you a good idea of - whether to walk or hitch a ride. Take the reported - latitude and longitude and enter them into your hand-held GPS - unit and have that compute a track to the landing location. -
- Both TeleMini and TeleMetrum will continue to transmit RDF - tones after landing, allowing you to locate the rocket by - following the radio signal if necessary. You may need to get - away from the clutter of the flight line, or even get up on - a hill (or your neighbor's RV roof) to receive the RDF signal. -
- The maximum height, speed and acceleration reported - during the flight are displayed for your admiring observers. - The accuracy of these immediate values depends on the quality - of your radio link and how many packets were received. - Recovering the on-board data after flight will likely yield - more precise results. -
- To get more detailed information about the flight, you can - click on the 'Graph Flight' button which will bring up a - graph window for the current flight. -
- When the TeleMetrum has a GPS fix, the Site Map tab will map - the rocket's position to make it easier for you to locate the - rocket, both while it is in the air, and when it has landed. The - rocket's state is indicated by color: white for pad, red for - boost, pink for fast, yellow for coast, light blue for drogue, - dark blue for main, and black for landed. -
- The map's scale is approximately 3m (10ft) per pixel. The map - can be dragged using the left mouse button. The map will attempt - to keep the rocket roughly centered while data is being received. -
- Images are fetched automatically via the Google Maps Static API, - and cached on disk for reuse. If map images cannot be downloaded, - the rocket's path will be traced on a dark gray background - instead. -
- You can pre-load images for your favorite launch sites - before you leave home; check out the 'Preload Maps' section below. -
- The altimeter records flight data to its internal flash memory. - TeleMetrum data is recorded at a much higher rate than the telemetry - system can handle, and is not subject to radio drop-outs. As - such, it provides a more complete and precise record of the - flight. The 'Save Flight Data' button allows you to read the - flash memory and write it to disk. As TeleMini has only a barometer, it - records data at the same rate as the telemetry signal, but there will be - no data lost due to telemetry drop-outs. -
- Clicking on the 'Save Flight Data' button brings up a list of - connected TeleMetrum and TeleDongle devices. If you select a - TeleMetrum device, the flight data will be downloaded from that - device directly. If you select a TeleDongle device, flight data - will be downloaded from an altimeter over radio link via the - specified TeleDongle. See the chapter on Controlling An Altimeter - Over The Radio Link for more information. -
- After the device has been selected, a dialog showing the - flight data saved in the device will be shown allowing you to - select which flights to download and which to delete. With - version 0.9 or newer firmware, you must erase flights in order - for the space they consume to be reused by another - flight. This prevents accidentally losing flight data - if you neglect to download data before flying again. Note that - if there is no more space available in the device, then no - data will be recorded during the next flight. -
- The file name for each flight log is computed automatically - from the recorded flight date, altimeter serial number and - flight number information. -
- Select this button and you are prompted to select a flight - record file, either a .telem file recording telemetry data or a - .eeprom file containing flight data saved from the altimeter - flash memory. -
- Once a flight record is selected, the flight monitor interface - is displayed and the flight is re-enacted in real time. Check - the Monitor Flight chapter above to learn how this window operates. -
- Select this button and you are prompted to select a flight - record file, either a .telem file recording telemetry data or a - .eeprom file containing flight data saved from - flash memory. -
- Once a flight record is selected, a window with two tabs is - opened. The first tab contains a graph with acceleration - (blue), velocity (green) and altitude (red) of the flight, - measured in metric units. The - apogee(yellow) and main(magenta) igniter voltages are also - displayed; high voltages indicate continuity, low voltages - indicate open circuits. The second tab contains some basic - flight statistics. -
- The graph can be zoomed into a particular area by clicking and - dragging down and to the right. Once zoomed, the graph can be - reset by clicking and dragging up and to the left. Holding down - control and clicking and dragging allows the graph to be panned. - The right mouse button causes a pop-up menu to be displayed, giving - you the option save or print the plot. -
- Note that telemetry files will generally produce poor graphs - due to the lower sampling rate and missed telemetry packets. - Use saved flight data in .eeprom files for graphing where possible. -
- This tool takes the raw data files and makes them available for - external analysis. When you select this button, you are prompted to - select a flight - data file (either .eeprom or .telem will do, remember that - .eeprom files contain higher resolution and more continuous - data). Next, a second dialog appears which is used to select - where to write the resulting file. It has a selector to choose - between CSV and KML file formats. -
- This is a text file containing the data in a form suitable for - import into a spreadsheet or other external data analysis - tool. The first few lines of the file contain the version and - configuration information from the altimeter, then - there is a single header line which labels all of the - fields. All of these lines start with a '#' character which - many tools can be configured to skip over. -
- The remaining lines of the file contain the data, with each - field separated by a comma and at least one space. All of - the sensor values are converted to standard units, with the - barometric data reported in both pressure, altitude and - height above pad units. -
- Select this button and then select either a TeleMetrum or - TeleDongle Device from the list provided. Selecting a TeleDongle - device will use the radio link to configure a remote altimeter. -
- The first few lines of the dialog provide information about the - connected device, including the product name, - software version and hardware serial number. Below that are the - individual configuration entries. -
- At the bottom of the dialog, there are four buttons: -
- Save. This writes any changes to the - configuration parameter block in flash memory. If you don't - press this button, any changes you make will be lost. -
- Reset. This resets the dialog to the most recently saved values, - erasing any changes you have made. -
- Reboot. This reboots the device. Use this to - switch from idle to pad mode by rebooting once the rocket is - oriented for flight, or to confirm changes you think you saved - are really saved. -
- Close. This closes the dialog. Any unsaved changes will be - lost. -
- The rest of the dialog contains the parameters to be configured. -
- This sets the altitude (above the recorded pad altitude) at - which the 'main' igniter will fire. The drop-down menu shows - some common values, but you can edit the text directly and - choose whatever you like. If the apogee charge fires below - this altitude, then the main charge will fire two seconds - after the apogee charge fires. -
- When flying redundant electronics, it's often important to - ensure that multiple apogee charges don't fire at precisely - the same time, as that can over pressurize the apogee deployment - bay and cause a structural failure of the air-frame. The Apogee - Delay parameter tells the flight computer to fire the apogee - charge a certain number of seconds after apogee has been - detected. -
- This configures which of the configured frequencies to use for both - telemetry and packet command mode. Note that if you set this - value via packet command mode, you will have to reconfigure - the TeleDongle frequency before you will be able to use packet - command mode again. -
- The radios in every Altus Metrum device are calibrated at the - factory to ensure that they transmit and receive on the - specified frequency. If you need to you can adjust the calibration - by changing this value. Do not do this without understanding what - the value means, read the appendix on calibration and/or the source - code for more information. To change a TeleDongle's calibration, - you must reprogram the unit completely. -
- This sets the call sign included in each telemetry packet. Set this - as needed to conform to your local radio regulations. -
- This sets the space (in kilobytes) allocated for each flight - log. The available space will be divided into chunks of this - size. A smaller value will allow more flights to be stored, - a larger value will record data from longer flights. -
- TeleMetrum and TeleMini provide two igniter channels as they - were originally designed as dual-deploy flight - computers. This configuration parameter allows the two - channels to be used in different configurations. -
- Dual Deploy. This is the usual mode of operation; the - 'apogee' channel is fired at apogee and the 'main' - channel at the height above ground specified by the - 'Main Deploy Altitude' during descent. -
- Redundant Apogee. This fires both channels at - apogee, the 'apogee' channel first followed after a two second - delay by the 'main' channel. -
- Redundant Main. This fires both channels at the - height above ground specified by the Main Deploy - Altitude setting during descent. The 'apogee' - channel is fired first, followed after a two second - delay by the 'main' channel. -
- Because it includes an accelerometer, TeleMetrum is - sensitive to the orientation of the board. By default, it - expects the antenna end to point forward. This parameter - allows that default to be changed, permitting the board to - be mounted with the antenna pointing aft instead. -
- Antenna Up. In this mode, the antenna end of the - TeleMetrum board must point forward, in line with the - expected flight path. -
- Antenna Down. In this mode, the antenna end of the - TeleMetrum board must point aft, in line with the - expected flight path. -
- This button presents a dialog so that you can configure the AltosUI global settings. -
- AltosUI provides voice announcements during flight so that you - can keep your eyes on the sky and still get information about - the current flight status. However, sometimes you don't want - to hear them. -
Enable—turns all voice announcements on and off
- Test Voice—Plays a short message allowing you to verify - that the audio system is working and the volume settings - are reasonable -
- AltosUI logs all telemetry data and saves all TeleMetrum flash - data to this directory. This directory is also used as the - staring point when selecting data files for display or export. -
- Click on the directory name to bring up a directory choosing - dialog, select a new directory and click 'Select Directory' to - change where AltosUI reads and writes data files. -
- This value is transmitted in each command packet sent from - TeleDongle and received from an altimeter. It is not used in - telemetry mode, as the callsign configured in the altimeter board - is included in all telemetry packets. Configure this - with the AltosUI operators call sign as needed to comply with - your local radio regulations. -
- This switches between metric units (meters) and imperial - units (feet and miles). This affects the display of values - use during flight monitoring, data graphing and all of the - voice announcements. It does not change the units used when - exporting to CSV files, those are always produced in metric units. -
- Selects the set of fonts used in the flight monitor - window. Choose between the small, medium and large sets. -
- This causes all communication with a connected device to be - dumped to the console from which AltosUI was started. If - you've started it from an icon or menu entry, the output - will simply be discarded. This mode can be useful to debug - various serial communication issues. -
- This brings up a dialog where you can configure the set of - frequencies shown in the various frequency menus. You can - add as many as you like, or even reconfigure the default - set. Changing this list does not affect the frequency - settings of any devices, it only changes the set of - frequencies shown in the menus. -
- Select this button and then select a TeleDongle Device from the list provided. -
- The first few lines of the dialog provide information about the - connected device, including the product name, - software version and hardware serial number. Below that are the - individual configuration entries. -
- Note that the TeleDongle itself doesn't save any configuration - data, the settings here are recorded on the local machine in - the Java preferences database. Moving the TeleDongle to - another machine, or using a different user account on the same - machine will cause settings made here to have no effect. -
- At the bottom of the dialog, there are three buttons: -
- Save. This writes any changes to the - local Java preferences file. If you don't - press this button, any changes you make will be lost. -
- Reset. This resets the dialog to the most recently saved values, - erasing any changes you have made. -
- Close. This closes the dialog. Any unsaved changes will be - lost. -
- The rest of the dialog contains the parameters to be configured. -
- This configures the frequency to use for both telemetry and - packet command mode. Set this before starting any operation - involving packet command mode so that it will use the right - frequency. Telemetry monitoring mode also provides a menu to - change the frequency, and that menu also sets the same Java - preference value used here. -
- The radios in every Altus Metrum device are calibrated at the - factory to ensure that they transmit and receive on the - specified frequency. To change a TeleDongle's calibration, - you must reprogram the unit completely, so this entry simply - shows the current value and doesn't allow any changes. -
- This reprograms any Altus Metrum device by using a TeleMetrum - or TeleDongle as a programming dongle. Please read the - directions for flashing devices in the Updating Device - Firmware chapter below. -
- Once you have the programmer and target devices connected, - push the 'Flash Image' button. That will present a dialog box - listing all of the connected devices. Carefully select the - programmer device, not the device to be programmed. -
- Next, select the image to flash to the device. These are named - with the product name and firmware version. The file selector - will start in the directory containing the firmware included - with the AltosUI package. Navigate to the directory containing - the desired firmware if it isn't there. -
- Next, a small dialog containing the device serial number and - RF calibration values should appear. If these values are - incorrect (possibly due to a corrupted image in the device), - enter the correct values here. -
- Finally, a dialog containing a progress bar will follow the - programming process. -
- When programming is complete, the target device will - reboot. Note that if the target device is connected via USB, you - will have to unplug it and then plug it back in for the USB - connection to reset so that you can communicate with the device - again. -
- This activates the igniter circuits in TeleMetrum to help test - recovery systems deployment. Because this command can operate - over the Packet Command Link, you can prepare the rocket as - for flight and then test the recovery system without needing - to snake wires inside the air-frame. -
- Selecting the 'Fire Igniter' button brings up the usual device - selection dialog. Pick the desired TeleDongle or TeleMetrum - device. This brings up another window which shows the current - continuity test status for both apogee and main charges. -
- Next, select the desired igniter to fire. This will enable the - 'Arm' button. -
- Select the 'Arm' button. This enables the 'Fire' button. The - word 'Arm' is replaced by a countdown timer indicating that - you have 10 seconds to press the 'Fire' button or the system - will deactivate, at which point you start over again at - selecting the desired igniter. -
- This listens for telemetry packets on all of the configured - frequencies, displaying information about each device it - receives a packet from. You can select which of the three - telemetry formats should be tried; by default, it only listens - for the standard telemetry packets used in v1.0 and later - firmware. -
- Before heading out to a new launch site, you can use this to - load satellite images in case you don't have internet - connectivity at the site. This loads a fairly large area - around the launch site, which should cover any flight you're likely to make. -
- There's a drop-down menu of launch sites we know about; if - your favorites aren't there, please let us know the lat/lon - and name of the site. The contents of this list are actually - downloaded at run-time, so as new sites are sent in, they'll - get automatically added to this list. -
- If the launch site isn't in the list, you can manually enter the lat/lon values -
- Clicking the 'Load Map' button will fetch images from Google - Maps; note that Google limits how many images you can fetch at - once, so if you load more than one launch site, you may get - some gray areas in the map which indicate that Google is tired - of sending data to you. Try again later. -
- First off, in the US, you need an amateur radio license or - other authorization to legally operate the radio transmitters that are part - of our products. -
- In the rocket itself, you just need a TeleMetrum or - TeleMini board and - a single-cell, 3.7 volt nominal Li-Po rechargeable battery. An - 850mAh battery weighs less than a 9V alkaline battery, and will - run a TeleMetrum for hours. - A 110mAh battery weighs less than a triple A battery and will run a TeleMetrum for - a few hours, or a TeleMini for much (much) longer. -
- By default, we ship the altimeters with a simple wire antenna. If your - electronics bay or the air-frame it resides within is made of carbon fiber, - which is opaque to RF signals, you may choose to have an SMA connector - installed so that you can run a coaxial cable to an antenna mounted - elsewhere in the rocket. -
- To receive the data stream from the rocket, you need an antenna and short - feed-line connected to one of our TeleDongle units. The - TeleDongle in turn plugs directly into the USB port on a notebook - computer. Because TeleDongle looks like a simple serial port, your computer - does not require special device drivers... just plug it in. -
- The GUI tool, AltosUI, is written in Java and runs across - Linux, Mac OS and Windows. There's also a suite of C tools - for Linux which can perform most of the same tasks. -
- After the flight, you can use the radio link to extract the more detailed data - logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the - TeleMetrum board directly. Pulling out the data without having to open up - the rocket is pretty cool! A USB cable is also how you charge the Li-Po - battery, so you'll want one of those anyway... the same cable used by lots - of digital cameras and other modern electronic stuff will work fine. -
- If your TeleMetrum-equipped rocket lands out of sight, you may enjoy having a hand-held GPS - receiver, so that you can put in a way-point for the last reported rocket - position before touch-down. This makes looking for your rocket a lot like - Geo-Caching... just go to the way-point and look around starting from there. -
- You may also enjoy having a ham radio "HT" that covers the 70cm band... you - can use that with your antenna to direction-find the rocket on the ground - the same way you can use a Walston or Beeline tracker. This can be handy - if the rocket is hiding in sage brush or a tree, or if the last GPS position - doesn't get you close enough because the rocket dropped into a canyon, or - the wind is blowing it across a dry lake bed, or something like that... Keith - and Bdale both currently own and use the Yaesu VX-7R at launches. -
- So, to recap, on the ground the hardware you'll need includes: -
-
- The best hand-held commercial directional antennas we've found for radio - direction finding rockets are from - - Arrow Antennas. - - The 440-3 and 440-5 are both good choices for finding a - TeleMetrum- or TeleMini- equipped rocket when used with a suitable 70cm HT. -
- Our software makes it easy to log the data from each flight, both the - telemetry received during the flight itself, and the more - complete data log recorded in the flash memory on the altimeter - board. Once this data is on your computer, our post-flight tools make it - easy to quickly get to the numbers everyone wants, like apogee altitude, - max acceleration, and max velocity. You can also generate and view a - standard set of plots showing the altitude, acceleration, and - velocity of the rocket during flight. And you can even export a TeleMetrum data file - usable with Google Maps and Google Earth for visualizing the flight path - in two or three dimensions! -
- Our ultimate goal is to emit a set of files for each flight that can be - published as a web page per flight, or just viewed on your local disk with - a web browser. -
- In the future, we intend to offer "companion boards" for the rocket that will - plug in to TeleMetrum to collect additional data, provide more pyro channels, - and so forth. -
- We are also working on the design of a hand-held ground terminal that will - allow monitoring the rocket's status, collecting data during flight, and - logging data after flight without the need for a notebook computer on the - flight line. Particularly since it is so difficult to read most notebook - screens in direct sunlight, we think this will be a great thing to have. -
- Because all of our work is open, both the hardware designs and the software, - if you have some great idea for an addition to the current Altus Metrum family, - feel free to dive in and help! Or let us know what you'd like to see that - we aren't already working on, and maybe we'll get excited about it too... -
Table of Contents
- Building high-power rockets that fly safely is hard enough. Mix - in some sophisticated electronics and a bunch of radio energy - and oftentimes you find few perfect solutions. This chapter - contains some suggestions about how to install Altus Metrum - products into the rocket air-frame, including how to safely and - reliably mix a variety of electronics into the same air-frame. -
- The first consideration is to ensure that the altimeter is - securely fastened to the air-frame. For TeleMetrum, we use - nylon standoffs and nylon screws; they're good to at least 50G - and cannot cause any electrical issues on the board. For - TeleMini, we usually cut small pieces of 1/16" balsa to fit - under the screw holes, and then take 2x56 nylon screws and - screw them through the TeleMini mounting holes, through the - balsa and into the underlying material. -
- The antenna supplied is just a piece of solid, insulated, - wire. If it gets damaged or broken, it can be easily - replaced. It should be kept straight and not cut; bending or - cutting it will change the resonant frequency and/or - impedance, making it a less efficient radiator and thus - reducing the range of the telemetry signal. -
- Keeping metal away from the antenna will provide better range - and a more even radiation pattern. In most rockets, it's not - entirely possible to isolate the antenna from metal - components; there are often bolts, all-thread and wires from other - electronics to contend with. Just be aware that the more stuff - like this around the antenna, the lower the range. -
- Make sure the antenna is not inside a tube made or covered - with conducting material. Carbon fiber is the most common - culprit here -- CF is a good conductor and will effectively - shield the antenna, dramatically reducing signal strength and - range. Metallic flake paint is another effective shielding - material which is to be avoided around any antennas. -
- If the ebay is large enough, it can be convenient to simply - mount the altimeter at one end and stretch the antenna out - inside. Taping the antenna to the sled can keep it straight - under acceleration. If there are metal rods, keep the - antenna as far away as possible. -
- For a shorter ebay, it's quite practical to have the antenna - run through a bulkhead and into an adjacent bay. Drill a small - hole in the bulkhead, pass the antenna wire through it and - then seal it up with glue or clay. We've also used acrylic - tubing to create a cavity for the antenna wire. This works a - bit better in that the antenna is known to stay straight and - not get folded by recovery components in the bay. Angle the - tubing towards the side wall of the rocket and it ends up - consuming very little space. -
- If you need to place the antenna at a distance from the - altimeter, you can replace the antenna with an edge-mounted - SMA connector, and then run 50Ω coax from the board to the - antenna. Building a remote antenna is beyond the scope of this - manual. -
- The GPS antenna and receiver in TeleMetrum are highly - sensitive and normally have no trouble tracking enough - satellites to provide accurate position information for - recovering the rocket. However, there are many ways to - attenuate the GPS signal. -
-
- Any altimeter will generate RFI; the digital circuits use - high-frequency clocks that spray radio interference across a - wide band. Altus Metrum altimeters generate intentional radio - signals as well, increasing the amount of RF energy around the board. -
- Rocketry altimeters also use precise sensors measuring air - pressure and acceleration. Tiny changes in voltage can cause - these sensor readings to vary by a huge amount. When the - sensors start mis-reporting data, the altimeter can either - fire the igniters at the wrong time, or not fire them at all. -
- Voltages are induced when radio frequency energy is - transmitted from one circuit to another. Here are things that - influence the induced voltage and current: -
- Altusmetrum altimeters measure altitude with a barometric - sensor, essentially measuring the amount of air above the - rocket to figure out how high it is. A large number of - measurements are taken as the altimeter initializes itself to - figure out the pad altitude. Subsequent measurements are then - used to compute the height above the pad. -
- To accurately measure atmospheric pressure, the ebay - containing the altimeter must be vented outside the - air-frame. The vent must be placed in a region of linear - airflow, have smooth edges, and away from areas of increasing or - decreasing pressure. -
- The barometric sensor in the altimeter is quite sensitive to - chemical damage from the products of APCP or BP combustion, so - make sure the ebay is carefully sealed from any compartment - which contains ejection charges or motors. -
- The most important aspect of any installation is careful - ground testing. Bringing an air-frame up to the LCO table which - hasn't been ground tested can lead to delays or ejection - charges firing on the pad, or, even worse, a recovery system - failure. -
- Do a 'full systems' test that includes wiring up all igniters - without any BP and turning on all of the electronics in flight - mode. This will catch any mistakes in wiring and any residual - RFI issues that might accidentally fire igniters at the wrong - time. Let the air-frame sit for several minutes, checking for - adequate telemetry signal strength and GPS lock. If any igniters - fire unexpectedly, find and resolve the issue before loading any - BP charges! -
- Ground test the ejection charges. Prepare the rocket for - flight, loading ejection charges and igniters. Completely - assemble the air-frame and then use the 'Fire Igniters' - interface through a TeleDongle to command each charge to - fire. Make sure the charge is sufficient to robustly separate - the air-frame and deploy the recovery system. -
Table of Contents
- The big concept to understand is that you have to use a - TeleDongle as a programmer to update a TeleMetrum or TeleMini, - and a TeleMetrum or other TeleDongle to program the TeleDongle - Due to limited memory resources in the cc1111, we don't support - programming directly over USB. -
- You may wish to begin by ensuring you have current firmware images. - These are distributed as part of the AltOS software bundle that - also includes the AltosUI ground station program. Newer ground - station versions typically work fine with older firmware versions, - so you don't need to update your devices just to try out new - software features. You can always download the most recent - version from http://www.altusmetrum.org/AltOS/. -
- We recommend updating the altimeter first, before updating TeleDongle. -
- Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini - firmware, but you use either a TeleMetrum or another TeleDongle as the programmer. -
- Be careful removing the programming cable from the locking 8-pin - connector on TeleMetrum. You'll need a fingernail or perhaps a thin - screwdriver or knife blade to gently pry the locking ears out - slightly to extract the connector. We used a locking connector on - TeleMetrum to help ensure that the cabling to companion boards - used in a rocket don't ever come loose accidentally in flight. -
Table of Contents
- Recording altimeter for model rocketry. -
- Supports dual deployment (can fire 2 ejection charges). -
- 70cm ham-band transceiver for telemetry down-link. -
- Barometric pressure sensor good to 45k feet MSL. -
- 1-axis high-g accelerometer for motor characterization, capable of - +/- 50g using default part. -
- On-board, integrated GPS receiver with 5Hz update rate capability. -
- On-board 1 megabyte non-volatile memory for flight data storage. -
- USB interface for battery charging, configuration, and data recovery. -
- Fully integrated support for Li-Po rechargeable batteries. -
- Uses Li-Po to fire e-matches, can be modified to support - optional separate pyro battery if needed. -
- 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube. -
- Recording altimeter for model rocketry. -
- Supports dual deployment (can fire 2 ejection charges). -
- 70cm ham-band transceiver for telemetry down-link. -
- Barometric pressure sensor good to 45k feet MSL. -
- On-board 5 kilobyte non-volatile memory for flight data storage. -
- RF interface for battery charging, configuration, and data recovery. -
- Support for Li-Po rechargeable batteries, using an external charger. -
- Uses Li-Po to fire e-matches, can be modified to support - optional separate pyro battery if needed. -
- 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube. -
- TeleMetrum seems to shut off when disconnected from the - computer. Make sure the battery is adequately charged. Remember the - unit will pull more power than the USB port can deliver before the - GPS enters "locked" mode. The battery charges best when TeleMetrum - is turned off. -
- It's impossible to stop the TeleDongle when it's in "p" mode, I have - to unplug the USB cable? Make sure you have tried to "escape out" of - this mode. If this doesn't work the reboot procedure for the - TeleDongle *is* to simply unplug it. 'cu' however will retain it's - outgoing buffer IF your "escape out" ('~~') does not work. - At this point using either 'ao-view' (or possibly - 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed - communication. -
- The amber LED (on the TeleMetrum) lights up when both - battery and USB are connected. Does this mean it's charging? - Yes, the yellow LED indicates the charging at the 'regular' rate. - If the led is out but the unit is still plugged into a USB port, - then the battery is being charged at a 'trickle' rate. -
- There are no "dit-dah-dah-dit" sound or lights like the manual mentions? - That's the "pad" mode. Weak batteries might be the problem. - It is also possible that the TeleMetrum is horizontal and the output - is instead a "dit-dit" meaning 'idle'. For TeleMini, it's possible that - it received a command packet which would have left it in "pad" mode. -
- How do I save flight data? - Live telemetry is written to file(s) whenever AltosUI is connected - to the TeleDongle. The file area defaults to ~/TeleMetrum - but is easily changed using the menus in AltosUI. The files that - are written end in '.telem'. The after-flight - data-dumped files will end in .eeprom and represent continuous data - unlike the .telem files that are subject to losses - along the RF data path. - See the above instructions on what and how to save the eeprom stored - data after physically retrieving your altimeter. Make sure to save - the on-board data after each flight; while the TeleMetrum can store - multiple flights, you never know when you'll lose the altimeter... -
- - Before AltosUI was written, using Altus Metrum devices required - some finesse with the Linux command line. There was a limited - GUI tool, ao-view, which provided functionality similar to the - Monitor Flight window in AltosUI, but everything else was a - fairly 80's experience. This appendix includes documentation for - using that software. - -
- Both TeleMetrum and TeleDongle can be directly communicated - with using USB ports. The first thing you should try after getting - both units plugged into to your computer's USB port(s) is to run - 'ao-list' from a terminal-window to see what port-device-name each - device has been assigned by the operating system. - You will need this information to access the devices via their - respective on-board firmware and data using other command line - programs in the AltOS software suite. -
- TeleMini can be communicated with through a TeleDongle device - over the radio link. When first booted, TeleMini listens for a - TeleDongle device and if it receives a packet, it goes into - 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be - launched. The easiest way to get it talking is to start the - communication link on the TeleDongle and the power up the - TeleMini board. -
- To access the device's firmware for configuration you need a terminal - program such as you would use to talk to a modem. The software - authors prefer using the program 'cu' which comes from the UUCP package - on most Unix-like systems such as Linux. An example command line for - cu might be 'cu -l /dev/ttyACM0', substituting the correct number - indicated from running the - ao-list program. Another reasonable terminal program for Linux is - 'cutecom'. The default 'escape' - character used by CU (i.e. the character you use to - issue commands to cu itself instead of sending the command as input - to the connected device) is a '~'. You will need this for use in - only two different ways during normal operations. First is to exit - the program by sending a '~.' which is called a 'escape-disconnect' - and allows you to close-out from 'cu'. The - second use will be outlined later. -
- All of the Altus Metrum devices share the concept of a two level - command set in their firmware. - The first layer has several single letter commands. Once - you are using 'cu' (or 'cutecom') sending (typing) a '?' - returns a full list of these - commands. The second level are configuration sub-commands accessed - using the 'c' command, for - instance typing 'c?' will give you this second level of commands - (all of which require the - letter 'c' to access). Please note that most configuration options - are stored only in Flash memory; TeleDongle doesn't provide any storage - for these options and so they'll all be lost when you unplug it. -
- Try setting these configuration ('c' or second level menu) values. A good - place to start is by setting your call sign. By default, the boards - use 'N0CALL' which is cute, but not exactly legal! - Spend a few minutes getting comfortable with the units, their - firmware, and 'cu' (or possibly 'cutecom'). - For instance, try to send - (type) a 'c r 2' and verify the channel change by sending a 'c s'. - Verify you can connect and disconnect from the units while in your - terminal program by sending the escape-disconnect mentioned above. -
- To set the radio frequency, use the 'c R' command to specify the - radio transceiver configuration parameter. This parameter is computed - using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and - the standard calibration reference frequency, 'S', (normally 434.550MHz): -
- R = F / S * C -
- Round the result to the nearest integer value. - As with all 'c' sub-commands, follow this with a 'c w' to write the - change to the parameter block in the on-board flash on - your altimeter board if you want the change to stay in place across reboots. -
- To set the apogee delay, use the 'c d' command. - As with all 'c' sub-commands, follow this with a 'c w' to write the - change to the parameter block in the on-board DataFlash chip. -
- To set the main deployment altitude, use the 'c m' command. - As with all 'c' sub-commands, follow this with a 'c w' to write the - change to the parameter block in the on-board DataFlash chip. -
- To calibrate the radio frequency, connect the UHF antenna port to a - frequency counter, set the board to 434.550MHz, and use the 'C' - command to generate a CW carrier. Wait for the transmitter temperature - to stabilize and the frequency to settle down. - Then, divide 434.550 MHz by the - measured frequency and multiply by the current radio cal value show - in the 'c s' command. For an unprogrammed board, the default value - is 1186611. Take the resulting integer and program it using the 'c f' - command. Testing with the 'C' command again should show a carrier - within a few tens of Hertz of the intended frequency. - As with all 'c' sub-commands, follow this with a 'c w' to write the - change to the parameter block in the on-board DataFlash chip. -
- Note that the 'reboot' command, which is very useful on the altimeters, - will likely just cause problems with the dongle. The *correct* way - to reset the dongle is just to unplug and re-plug it. -
- A fun thing to do at the launch site and something you can do while - learning how to use these units is to play with the radio link access - between an altimeter and the TeleDongle. Be aware that you *must* create - some physical separation between the devices, otherwise the link will - not function due to signal overload in the receivers in each device. -
- Now might be a good time to take a break and read the rest of this - manual, particularly about the two "modes" that the altimeters - can be placed in. TeleMetrum uses the position of the device when booting - up will determine whether the unit is in "pad" or "idle" mode. TeleMini - enters "idle" mode when it receives a command packet within the first 5 seconds - of being powered up, otherwise it enters "pad" mode. -
- You can access an altimeter in idle mode from the TeleDongle's USB - connection using the radio link - by issuing a 'p' command to the TeleDongle. Practice connecting and - disconnecting ('~~' while using 'cu') from the altimeter. If - you cannot escape out of the "p" command, (by using a '~~' when in - CU) then it is likely that your kernel has issues. Try a newer version. -
- Using this radio link allows you to configure the altimeter, test - fire e-matches and igniters from the flight line, check pyro-match - continuity and so forth. You can leave the unit turned on while it - is in 'idle mode' and then place the - rocket vertically on the launch pad, walk away and then issue a - reboot command. The altimeter will reboot and start sending data - having changed to the "pad" mode. If the TeleDongle is not receiving - this data, you can disconnect 'cu' from the TeleDongle using the - procedures mentioned above and THEN connect to the TeleDongle from - inside 'ao-view'. If this doesn't work, disconnect from the - TeleDongle, unplug it, and try again after plugging it back in. -
- In order to reduce the chance of accidental firing of pyrotechnic - charges, the command to fire a charge is intentionally somewhat - difficult to type, and the built-in help is slightly cryptic to - prevent accidental echoing of characters from the help text back at - the board from firing a charge. The command to fire the apogee - drogue charge is 'i DoIt drogue' and the command to fire the main - charge is 'i DoIt main'. -
- On TeleMetrum, the GPS will eventually find enough satellites, lock in on them, - and 'ao-view' will both auditorily announce and visually indicate - that GPS is ready. - Now you can launch knowing that you have a good data path and - good satellite lock for flight data and recovery. Remember - you MUST tell ao-view to connect to the TeleDongle explicitly in - order for ao-view to be able to receive data. -
- The altimeters provide RDF (radio direction finding) tones on - the pad, during descent and after landing. These can be used to - locate the rocket using a directional antenna; the signal - strength providing an indication of the direction from receiver to rocket. -
- TeleMetrum also provides GPS tracking data, which can further simplify - locating the rocket once it has landed. (The last good GPS data - received before touch-down will be on the data screen of 'ao-view'.) -
- Once you have recovered the rocket you can download the eeprom - contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over - either a USB cable or over the radio link using TeleDongle. - And by following the man page for 'ao-postflight' you can create - various data output reports, graphs, and even KML data to see the - flight trajectory in Google-earth. (Moving the viewing angle making - sure to connect the yellow lines while in Google-earth is the proper - technique.) -
- As for ao-view.... some things are in the menu but don't do anything - very useful. The developers have stopped working on ao-view to focus - on a new, cross-platform ground station program. So ao-view may or - may not be updated in the future. Mostly you just use - the Log and Device menus. It has a wonderful display of the incoming - flight data and I am sure you will enjoy what it has to say to you - once you enable the voice output! -
Table of Contents
- There are only two calibrations required for a TeleMetrum board, and - only one for TeleDongle and TeleMini. All boards are shipped from - the factory pre-calibrated, but the procedures are documented here - in case they are ever needed. Re-calibration is not supported by - AltosUI, you must connect to the board with a serial terminal program - and interact directly with the on-board command interpreter to effect - calibration. -
- The radio frequency is synthesized from a clock based on the 48 MHz - crystal on the board. The actual frequency of this oscillator - must be measured to generate a calibration constant. While our - GFSK modulation - bandwidth is wide enough to allow boards to communicate even when - their oscillators are not on exactly the same frequency, performance - is best when they are closely matched. - Radio frequency calibration requires a calibrated frequency counter. - Fortunately, once set, the variation in frequency due to aging and - temperature changes is small enough that re-calibration by customers - should generally not be required. -
- To calibrate the radio frequency, connect the UHF antenna port to a - frequency counter, set the board to 434.550MHz, and use the 'C' - command in the on-board command interpreter to generate a CW - carrier. For TeleMetrum, this is best done over USB. For TeleMini, - note that the only way to escape the 'C' command is via power cycle - since the board will no longer be listening for commands once it - starts generating a CW carrier. -
- Wait for the transmitter temperature to stabilize and the frequency - to settle down. Then, divide 434.550 MHz by the - measured frequency and multiply by the current radio cal value show - in the 'c s' command. For an unprogrammed board, the default value - is 1186611. Take the resulting integer and program it using the 'c f' - command. Testing with the 'C' command again should show a carrier - within a few tens of Hertz of the intended frequency. - As with all 'c' sub-commands, follow this with a 'c w' to write the - change to the parameter block in the on-board DataFlash chip. -
- Note that any time you re-do the radio frequency calibration, the - radio frequency is reset to the default 434.550 Mhz. If you want - to use another frequency, you will have to set that again after - calibration is completed. -
- The TeleMetrum accelerometer we use has its own 5 volt power - supply and - the output must be passed through a resistive voltage divider to match - the input of our 3.3 volt ADC. This means that unlike the barometric - sensor, the output of the acceleration sensor is not ratio-metric to - the ADC converter, and calibration is required. Explicitly - calibrating the accelerometers also allows us to load any device - from a Freescale family that includes at least +/- 40g, 50g, 100g, - and 200g parts. Using gravity, - a simple 2-point calibration yields acceptable results capturing both - the different sensitivities and ranges of the different accelerometer - parts and any variation in power supply voltages or resistor values - in the divider network. -
- To calibrate the acceleration sensor, use the 'c a 0' command. You - will be prompted to orient the board vertically with the UHF antenna - up and press a key, then to orient the board vertically with the - UHF antenna down and press a key. Note that the accuracy of this - calibration depends primarily on how perfectly vertical and still - the board is held during the cal process. As with all 'c' - sub-commands, follow this with a 'c w' to write the - change to the parameter block in the on-board DataFlash chip. -
- The +1g and -1g calibration points are included in each telemetry - frame and are part of the header stored in onboard flash to be - downloaded after flight. We always store and return raw ADC - samples for each sensor... so nothing is permanently "lost" or - "damaged" if the calibration is poor. -
- In the unlikely event an accel cal goes badly, it is possible - that TeleMetrum may always come up in 'pad mode' and as such not be - listening to either the USB or radio link. If that happens, - there is a special hook in the firmware to force the board back - in to 'idle mode' so you can re-do the cal. To use this hook, you - just need to ground the SPI clock pin at power-on. This pin is - available as pin 2 on the 8-pin companion connector, and pin 1 is - ground. So either carefully install a fine-gauge wire jumper - between the two pins closest to the index hole end of the 8-pin - connector, or plug in the programming cable to the 8-pin connector - and use a small screwdriver or similar to short the two pins closest - to the index post on the 4-pin end of the programming cable, and - power up the board. It should come up in 'idle mode' (two beeps), - allowing a re-cal. -
- Version 1.1 is a minor release. It provides a few new features in AltosUI - and the AltOS firmware and fixes bugs. -
- AltOS Firmware Changes -
-
- AltosUI Changes -
-
- Version 1.0.1 is a major release, adding support for the TeleMini - device and lots of new AltosUI features -
- AltOS Firmware Changes -
-
- AltosUI Changes -
-
- Version 0.9.2 is an AltosUI bug-fix release, with no firmware changes. -
- Version 0.9 adds a few new firmware features and accompanying - AltosUI changes, along with new hardware support. -
- Version 0.8 offers a major upgrade in the AltosUI - interface. Significant new features include: -
-Version 0.7.1 is the first release containing our new cross-platform Java-based user interface. AltosUI can: -
Copyright © 2018 Bdale Garbee and Keith Packard
+ This document is released under the terms of the + + Creative Commons ShareAlike 3.0 + + license. +
Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing âThe +Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter +Kitâ which formed the basis of the original Getting Started chapter +in this manual. Bob was one of our first customers for a production +TeleMetrum, and his continued enthusiasm and contributions +are immensely gratifying and highly appreciated!
And thanks to Anthony (AJ) Towns for major contributions including +the AltosUI graphing and site map code and associated documentation. +Free software means that our customers and friends can become our +collaborators, and we certainly appreciate this level of +contribution!
Have fun using these products, and we hope to meet all of you +out on the rocket flight line somewhere.
Bdale Garbee, KB0G
+NAR #87103, TRA #12201
Keith Packard, KD7SQG
+NAR #88757, TRA #12200
Table of Contents
List of Figures
List of Tables
Welcome to the Altus Metrum community! Our circuits and software reflect +our passion for both hobby rocketry and Free Software. We hope their +capabilities and performance will delight you in every way, but by +releasing all of our hardware and software designs under open licenses, +we also hope to empower you to take as active a role in our collective +future as you wish!
The first device created for our community was TeleMetrum, a dual +deploy altimeter with fully integrated GPS and radio telemetry +as standard features, and a âcompanion interfaceâ that will +support optional capabilities in the future. The latest version +of TeleMetrum, v2.0, has all of the same features but with +improved sensors and radio to offer increased performance.
Our second device was TeleMini, a dual deploy altimeter with +radio telemetry and radio direction finding. The first version +of this device was only 13mm by 38mm (½ inch by 1½ inches) and +could fit easily in an 18mm air-frame. The latest version, v3.0, +includes a beeper, higher power radio, extended on-board +flight logging and an improved barometric sensor.
TeleMega is our most sophisticated device, including six pyro +channels (four of which are fully programmable), integrated GPS, +integrated gyroscopes for staging/air-start inhibit and high +performance telemetry.
EasyMini is a dual-deploy altimeter with logging and built-in +USB data download.
EasyMega is essentially a TeleMega board with the GPS receiver +and telemetry transmitter removed. It offers the same 6 pyro +channels and integrated gyroscopes for staging/air-start inhibit.
TeleDongle v0.2 was our first ground station, providing a USB to RF +interfaces for communicating with the altimeters. Combined with +your choice of antenna and notebook computer, TeleDongle and our +associated user interface software form a complete ground +station capable of logging and displaying in-flight telemetry, +aiding rocket recovery, then processing and archiving flight +data for analysis and review. The latest version, TeleDongle +v3, has all new electronics with a higher performance radio +for improved range.
For a slightly more portable ground station experience that also +provides direct rocket recovery support, TeleBT offers flight +monitoring and data logging using a Bluetooth⢠connection between +the receiver and an Android device that has the AltosDroid +application installed from the Google Play store.
More products will be added to the Altus Metrum family over time, and +we currently envision that this will be a single, comprehensive manual +for the entire product family.
The first thing to do after you open the box is to hook up a +battery and charge it if necessary.
For TeleMetrum, TeleMega and EasyMega, the battery can be charged by plugging it into the +corresponding socket of the device and then using the USB +cable to plug the flight computer into your computerâs USB socket. The +on-board circuitry will charge the battery whenever it is plugged +in, because the on-off switch does NOT control the +charging circuitry. +The Lithium Polymer +TeleMini and +EasyMini battery can be charged by disconnecting it +from the board and plugging it into a standalone +battery charger such as LipoCharger, and +connecting that via a USB cable to a laptop or other +USB power source.
You can also choose to use another battery with +EasyMini, anything supplying between 4 and 12 volts should +work fine (like a standard 9V battery), but if you are planning +to fire pyro charges, ground testing is required to verify that +the battery supplies enough current to fire your chosen e-matches.
On TeleMetrum v1 boards, when the GPS chip is initially +searching for satellites, TeleMetrum will consume more current +than it pulls from the USB port, so the battery must be +attached in order to get satellite lock. Once GPS is locked, +the current consumption goes back down enough to enable charging +while running. So itâs a good idea to fully charge the battery +as your first item of business so there is no issue getting and +maintaining satellite lock. The yellow charge indicator led +will go out when the battery is nearly full and the charger goes +to trickle charge. It can take several hours to fully recharge a +deeply discharged battery.
TeleMetrum v2.0, TeleMega and EasyMega use a higher power battery charger, +allowing them to charge the battery while running the board at +maximum power. When the battery is charging, or when the board +is consuming a lot of power, the red LED will be lit. When the +battery is fully charged, the green LED will be lit. When the +battery is damaged or missing, both LEDs will be lit, which +appears yellow.
There are two ground stations available, the TeleDongle USB to +RF interface and the TeleBT Bluetooth/USB to RF interface. If +you plug either of these in to your Mac or Linux computer it should +âjust workâ, showing up as a serial port device. Windows systems need +driver information that is part of the AltOS download to know that the +existing USB modem driver will work. We therefore recommend installing +our software before plugging in TeleDongle if you are using a Windows +computer. If you are using an older version of Linux and are having +problems, try moving to a fresher kernel (2.6.33 or +newer).
Next you should obtain and install the AltOS software. +The AltOS distribution includes the AltosUI ground +station program, current firmware images for all of +the hardware, and a number of standalone utilities +that are rarely needed. Pre-built binary packages are +available for Linux, Microsoft Windows, Mac OSX. Full +source code and build instructions are also +available. The latest version may always be downloaded +from http://altusmetrum.org/AltOS
TeleBT can also connect to an Android device over +BlueTooth or USB. The +AltosDroid +Android application is available from the +Google Play system.
You donât need a data plan to use AltosDroid, but +without network access, youâll want to download +offline map data before wandering away from the +network.
Here are general instructions for hooking up an Altus Metrum +flight computer. Instructions specific to each model will be +found in the section devoted to that model below.
To prevent electrical interference from affecting the +operation of the flight computer, itâs important to always +twist pairs of wires connected to the board. Twist the switch +leads, the pyro leads and the battery leads. This reduces +interference through a mechanism called common mode rejection.
All Altus Metrum flight computers have a two pin JST PH +series connector to connect up a single-cell Lithium Polymer +cell (3.7V nominal). You can purchase matching batteries +from the Altus Metrum store, or other vendors, or you can +make your own. Pin 1 of the connector is positive, pin 2 is +negative. Spark Fun sells a cable with the connector +attached, which they call a +JST Jumper 2 Wire Assembly
Many RC vendors also sell lithium polymer batteries with +this same connector. All that we have found use the opposite +polarity, and if you use them that way, you will damage or +destroy the flight computer.
Altus Metrum flight computers always have two screws for +each pyro charge. This means you shouldnât need to put two +wires into a screw terminal or connect leads from pyro +charges together externally.
On the flight computer, one lead from each charge is hooked +to the positive battery terminal through the power switch. +The other lead is connected through the pyro circuit, which +is connected to the negative battery terminal when the pyro +circuit is fired.
Altus Metrum flight computers need an external power switch +to turn them on. This disconnects both the computer and the +pyro charges from the battery, preventing the charges from +firing when in the Off position. The switch is in-line with +the positive battery terminal.
Altus Metrum flight computers include a beeper to +provide information about the state of the system. +TeleMini doesnât have room for a beeper, so instead it +uses an LED, which works the same, except for every +beep is replaced with the flash of the LED.
Hereâs a short summary of all of the modes and the +beeping +(or flashing, in the case of TeleMini v1) +that accompanies each mode. In the description of the +beeping pattern, âditâ means a short beep while "dah" +means a long beep (three times as long). âBrapâ means +a long dissonant tone.
Table 3.1. AltOS Modes
Mode Name | Abbreviation | Beeps | Description |
Startup | S | battery voltage in decivolts | Calibrating sensors, detecting orientation. |
Idle | I | dit dit | Ready to accept commands over USB +or radio link. |
Pad | P | dit dah dah dit | Waiting for launch. Not listening for commands. |
Boost | B | dah dit dit dit | Accelerating upwards. |
Fast | F | dit dit dah dit | Decelerating, but moving faster than 200m/s. |
Coast | C | dah dit dah dit | Decelerating, moving slower than 200m/s |
Drogue | D | dah dit dit | Descending after apogee. Above main height. |
Main | M | dah dah | Descending. Below main height. |
Landed | L | dit dah dit dit | Stable altitude for at least ten seconds. |
Sensor error | X | dah dit dit dah | Error detected during sensor calibration. |
Hereâs a summary of all of the Pad and Idle mode +indications. In Idle mode, youâll hear one of these +just once after the two short dits indicating idle +mode. In Pad mode, after the dit dah dah dit +indicating Pad mode, youâll hear these once every five +seconds.
Table 3.2. Pad/Idle Indications
Name | Beeps | Description |
---|---|---|
Neither | brap | No continuity detected on either apogee or main igniters. |
Apogee | dit | Continuity detected only on apogee igniter. |
Main | dit dit | Continuity detected only on main igniter. |
Both | dit dit dit | Continuity detected on both igniters. |
Storage Full | warble | On-board data logging storage is full. This will +not prevent the flight computer from safely +controlling the flight or transmitting telemetry +signals, but no record of the flight will be +stored in on-board flash. |
Additional Igniters | four very short beeps | Continuity indication for the four additional pyro +channels on TeleMega and EasyMega. One high tone for +no continuity, one low tone for continuity. These are +produced after the continuity indicators for the two +primary igniter channels. |
For devices with a radio transmitter, in addition to +the digital and APRS telemetry signals, you can also +receive audio tones with a standard amateur +70cm FM receiver. While on the pad, you will hear +igniter status once every five seconds.
Table 3.3. Pad Radio Indications
Name | Beeps | Description |
---|---|---|
Neither | ½ second tone | No continuity detected on either apogee or main igniters. |
Apogee | dit | Continuity detected only on apogee igniter. |
Main | dit dit | Continuity detected only on main igniter. |
Both | dit dit dit | Continuity detected on both igniters. |
During ascent, the tones will be muted to allow the +telemetry data to consume the full radio bandwidth.
During descent and after landing, a ½ second tone will +be transmitted every five seconds. This can be used to +find the rocket using RDF techniques when the signal +is too weak to receive GPS information via telemetry +or APRS.
Connect a battery and power switch and turn the switch +to "on". The flight computer will signal power on by +reporting the battery voltage and then perform an internal self +test and sensor calibration.
Once the self test and calibration are complete, there +are two modes that an Altus Metrum flight computer can +operate in:
For flight computers with accelerometers (TeleMetrum, +EasyMega and TeleMega), the mode is selected by the +orientation of the board during the self test +interval. If the board is pointing upwards as if ready +to fly, it will enter Flight/Pad mode. Otherwise, it will +enter Idle mode.
For EasyMini, if the USB cable is connected to a +computer, it will enter Idle mode. Otherwise, it will +enter Flight/Pad mode.
For TeleMini v1.0, if a packet link is waiting to +connect when the device is powered on, it will enter +Idle mode, otherwise it will enter Flight/Pad mode.
You can see in Section 3.5, âUnderstanding Beepsâ +how to tell which mode the flight computer is in.
You can use an active switch circuit, such as the +Featherweight Magnetic Switch, with any Altus Metrum +flight computer. These require three connections, one to +the battery, one to the positive power input on the flight +computer and one to ground. Find instructions on how to +hook these up for each flight computer below. Then follow +the instructions that come with your active switch to +connect it up.
As mentioned above in Section 3.3, âHooking Up Pyro Chargesâ, one +lead for each of the pyro charges is connected through +the power switch directly to the positive battery +terminal. The other lead is connected to the pyro +circuit, which connects it to the negative battery +terminal when the pyro circuit is fired. The pyro +circuit on all of the flight computers is designed to +handle up to 16V.
To use a separate pyro battery, connect the negative pyro +battery terminal to the flight computer ground terminal, +the positive battery terminal to the igniter and the other +igniter lead to the negative pyro terminal on the flight +computer. When the pyro channel fires, it will complete the +circuit between the negative pyro terminal and the ground +terminal, firing the igniter. Specific instructions on how +to hook this up for each flight computer will be found +in the section below for that flight computer.
EasyMini +and TeleMini v2 are +designed to use either a +lithium polymer battery or any other battery producing +between 4 and 12 volts, such as a rectangular 9V +battery.
TeleMega, EasyMega and TeleMetrum are only designed to +operate off a single-cell Lithium Polymer battery and +cannot be used with any other kind. Connecting a +different kind of battery to any of these will destroy +the board.
TeleMetrum is a 1 inch by 2¾ inch circuit board. It was designed to +fit inside coupler for 29mm air-frame tubing, but using it in a tube that +small in diameter may require some creativity in mounting and wiring +to succeed! The presence of an accelerometer means TeleMetrum should +be aligned along the flight axis of the airframe, and by default the ¼ +wave UHF wire antenna should be on the nose-cone end of the board. The +antenna wire is about 7 inches long, and wiring for a power switch and +the e-matches for apogee and main ejection charges depart from the +fin can end of the board, meaning an ideal âsimpleâ avionics +bay for TeleMetrum should have at least 10 inches of interior length.
There are two generations of the TeleMetrum design. The +major changes in the v2 generation are:
Otherwise, theyâre the same size, with mounting holes and +screw terminals in the same position.
TeleMetrum has six screw terminals on the end of the board +opposite the telemetry antenna. Two are for the power +switch, and two each for the apogee and main igniter +circuits. Using the picture above and starting from the top, +the terminals are as follows:
Table 4.1. TeleMetrum Screw Terminals
Terminal # | Terminal Name | Description |
---|---|---|
1 | Switch Output | Switch connection to flight computer |
2 | Switch Input | Switch connection to positive battery terminal |
3 | Main + | Main pyro channel common connection to battery |
4 | Main - | Main pyro channel connection to pyro circuit |
5 | Apogee + | Apogee pyro channel common connection to battery |
6 | Apogee - | Apogee pyro channel connection to pyro circuit |
As described above, using an external pyro battery involves +connecting the negative battery terminal to the flight +computer ground, connecting the positive battery terminal to +one of the igniter leads and connecting the other igniter +lead to the per-channel pyro circuit connection.
To connect the negative battery terminal to the TeleMetrum +ground, insert a small piece of wire, 24 to 28 gauge +stranded, into the GND hole just above the screw terminal +strip and solder it in place.
Connecting the positive battery terminal to the pyro +charges must be done separate from TeleMetrum, by soldering +them together or using some other connector.
The other lead from each pyro charge is then inserted into +the appropriate per-pyro channel screw terminal (terminal 4 for the +Main charge, terminal 6 for the Apogee charge).
As explained above, an external active switch requires three +connections, one to the positive battery terminal, one to +the flight computer positive input and one to ground.
The positive battery terminal is available on screw terminal +2, the positive flight computer input is on terminal 1. To +hook a lead to ground, solder a piece of wire, 24 to 28 +gauge stranded, to the GND hole just above terminal 1.
TeleMini v3 is 0.5 inches by 1.67 inches. It was +designed to fit inside an 18mm air-frame tube, but using it in +a tube that small in diameter may require some creativity in +mounting and wiring to succeed! Since there is no +accelerometer, TeleMini can be mounted in any convenient +orientation. The default ¼ wave UHF wire antenna attached to +the center of one end of the board is about 7 inches long. Screw +terminals for the power switch are located in the +middle of the board. Screw terminals for the e-matches for +apogee and main ejection charges depart from the other end of +the board, meaning an ideal âsimpleâ avionics bay for TeleMini +should have at least 9 inches of interior length.
TeleMini v3 has four screw terminals on the end of the +board opposite the telemetry antenna. Two are for the apogee +and two are for main igniter circuits. Another two +screw terminals are located in the middle of the board +for the power switch. Using the +picture above and starting from the top for the pyro terminals +and from the left for the power switch terminals, the +connections are as follows:
Table 5.1. TeleMini v3 Screw Terminals
Terminal # | Terminal Name | Description |
---|---|---|
1 | Apogee - | Apogee pyro channel connection to pyro circuit |
2 | Apogee | Apogee pyro channel common connection to battery |
3 | Main - | Main pyro channel connection to pyro circuit |
4 | Main | Main pyro channel common connection to battery |
Left | Switch Output | Switch connection to flight computer |
Right | Switch Input | Switch connection to positive battery terminal |
As described above, using an external pyro battery involves +connecting the negative battery terminal to the flight +computer ground, connecting the positive battery terminal to +one of the igniter leads and connecting the other igniter +lead to the per-channel pyro circuit connection. Because +there is no solid ground connection to use on TeleMini, this +is not recommended.
The only available ground connection on TeleMini v3 are +the two mounting holes next to the telemetry +antenna. Somehow connect a small piece of wire to one of +those holes and hook it to the negative pyro battery terminal.
Connecting the positive battery terminal to the pyro +charges must be done separate from TeleMini v3, by soldering +them together or using some other connector.
The other lead from each pyro charge is then inserted into +the appropriate per-pyro channel screw terminal (terminal 3 for the +Main charge, terminal 1 for the Apogee charge).
As explained above, an external active switch requires three +connections, one to the positive battery terminal, one to +the flight computer positive input and one to ground. Again, +because TeleMini doesnât have any good ground connection, +this is not recommended.
The positive battery terminal is available on the Right +power switch wire, the positive flight computer input is on +the left power switch wire. Hook a lead to either of the +mounting holes for a ground connection.
EasyMini is built on a 0.8 inch by 1½ inch circuit board. Itâs +designed to fit in a 24mm coupler tube.
You usually donât need to configure EasyMini at all; itâs set +up to do dual-deployment with an event at apogee to separate +the airframe and deploy a drogue and another event at 250m +(820ft) to deploy the main. Install EasyMini in your airframe, +hook up a battery, igniters and a power switch and youâre +ready to fly.
EasyMini has two sets of four screw terminals near one end of the +board. Using the picture +above, the top four have connections for the main pyro +circuit and an external battery and the bottom four have +connections for the apogee pyro circuit and the power +switch. Counting from the left, the connections are as follows:
Table 6.1. EasyMini Screw Terminals
Terminal # | Terminal Name | Description |
---|---|---|
Top 1 | Main - | Main pyro channel connection to pyro circuit |
Top 2 | Main | Main pyro channel common connection to battery |
Top 3 | Battery | Positive external battery terminal |
Top 4 | Battery - | Negative external battery terminal |
Bottom 1 | Apogee - | Apogee pyro channel connection to pyro circuit |
Bottom 2 | Apogee | Apogee pyro channel common connection to battery |
Bottom 3 | Switch Output | Switch connection to flight computer |
Bottom 4 | Switch Input | Switch connection to positive battery terminal |
There are two possible battery connections on +EasyMini. You can use either method; both feed +through the power switch terminals.
One battery connection is the standard Altus Metrum +white JST plug. This mates with single-cell Lithium +Polymer batteries sold by Altus Metrum.
The other is a pair of screw terminals marked Battery ++ and Battery -. Connect a battery from 4 to 12 +volts to these terminals, being careful to match polarity.
Because EasyMini allows for batteries other than the +standard Altus Metrum Lithium Polymer cells, it cannot +incorporate a battery charger circuit. Therefore, when +using a Litium Polymer cell, youâll need an external +charger. These are available from Altus Metrum, or +from Spark Fun.
As described above, using an external pyro battery involves +connecting the negative battery terminal to the flight +computer ground, connecting the positive battery terminal to +one of the igniter leads and connecting the other igniter +lead to the per-channel pyro circuit connection.
To connect the negative pyro battery terminal to EasyMini +ground, connect it to the negative external battery +connection, top terminal 4.
Connecting the positive battery terminal to the pyro +charges must be done separate from EasyMini, by soldering +them together or using some other connector.
The other lead from each pyro charge is then inserted into +the appropriate per-pyro channel screw terminal (top +terminal 1 for the Main charge, bottom terminal 1 for the +Apogee charge).
As explained above, an external active switch requires three +connections, one to the positive battery terminal, one to +the flight computer positive input and one to ground. Use +the negative external battery connection, top terminal 4 for +ground.
The positive battery terminal is available on bottom +terminal 4, the positive flight computer input is on the +bottom terminal 3.
TeleMega is a 1¼ inch by 3¼ inch circuit board. It was +designed to easily fit in a 38mm coupler. Like TeleMetrum, +TeleMega has an accelerometer and so it must be mounted so that +the board is aligned with the flight axis. It can be mounted +either antenna up or down.
TeleMega v2.0 has a few minor changes from v1.0:
None of these affect operation using the stock firmware, but +they do mean that the device needs different firmware to +operate correctly, so make sure you load the right firmware +when reflashing the device.
TeleMega has two sets of nine screw terminals on the end of +the board opposite the telemetry antenna. They are as follows:
Table 7.1. TeleMega Screw Terminals
Terminal # | Terminal Name | Description |
---|---|---|
Top 1 | Switch Input | Switch connection to positive battery terminal |
Top 2 | Switch Output | Switch connection to flight computer |
Top 3 | GND | Ground connection for use with external active switch |
Top 4 | Main - | Main pyro channel connection to pyro circuit |
Top 5 | Main | Main pyro channel common connection to battery |
Top 6 | Apogee - | Apogee pyro channel connection to pyro circuit |
Top 7 | Apogee | Apogee pyro channel common connection to battery |
Top 8 | D - | D pyro channel connection to pyro circuit |
Top 9 | D | D pyro channel common connection to battery |
Bottom 1 | GND | Ground connection for negative pyro battery terminal |
Bottom 2 | Pyro | Positive pyro battery terminal |
Bottom 3 | Lipo | Power switch output. Use to connect main battery to pyro battery input |
Bottom 4 | A - | A pyro channel connection to pyro circuit |
Bottom 5 | A | A pyro channel common connection to battery |
Bottom 6 | B - | B pyro channel connection to pyro circuit |
Bottom 7 | B | B pyro channel common connection to battery |
Bottom 8 | C - | C pyro channel connection to pyro circuit |
Bottom 9 | C | C pyro channel common connection to battery |
TeleMega provides explicit support for an external pyro +battery. All that is required is to remove the jumper +between the lipo terminal (Bottom 3) and the pyro terminal +(Bottom 2). Then hook the negative pyro battery terminal to ground +(Bottom 1) and the positive pyro battery to the pyro battery +input (Bottom 2). You can then use the existing pyro screw +terminals to hook up all of the pyro charges.
Because TeleMega has built-in support for a separate pyro +battery, if you want to fly with just one battery running +both the computer and firing the charges, you need to +connect the flight computer battery to the pyro +circuit. TeleMega has two screw terminals for thisâhook a +wire from the Lipo terminal (Bottom 3) to the Pyro terminal +(Bottom 2).
As explained above, an external active switch requires three +connections, one to the positive battery terminal, one to +the flight computer positive input and one to ground.
The positive battery terminal is available on Top terminal +1, the positive flight computer input is on Top terminal +2. Ground is on Top terminal 3.
EasyMega is a 1¼ inch by 2¼ inch circuit board. It was +designed to easily fit in a 38mm coupler. Like TeleMetrum, +EasyMega has an accelerometer and so it must be mounted so that +the board is aligned with the flight axis. It can be mounted +either antenna up or down.
EasyMega has two sets of nine screw terminals on the end of +the board opposite the telemetry antenna. They are as follows:
Table 8.1. EasyMega Screw Terminals
Terminal # | Terminal Name | Description |
---|---|---|
Top 1 | Switch Input | Switch connection to positive battery terminal |
Top 2 | Switch Output | Switch connection to flight computer |
Top 3 | GND | Ground connection for use with external active switch |
Top 4 | Main - | Main pyro channel connection to pyro circuit |
Top 5 | Main | Main pyro channel common connection to battery |
Top 6 | Apogee - | Apogee pyro channel connection to pyro circuit |
Top 7 | Apogee | Apogee pyro channel common connection to battery |
Top 8 | D - | D pyro channel connection to pyro circuit |
Top 9 | D | D pyro channel common connection to battery |
Bottom 1 | GND | Ground connection for negative pyro battery terminal |
Bottom 2 | Pyro | Positive pyro battery terminal |
Bottom 3 | Lipo | Power switch output. Use to connect main battery to pyro battery input |
Bottom 4 | A - | A pyro channel connection to pyro circuit |
Bottom 5 | A | A pyro channel common connection to battery |
Bottom 6 | B - | B pyro channel connection to pyro circuit |
Bottom 7 | B | B pyro channel common connection to battery |
Bottom 8 | C - | C pyro channel connection to pyro circuit |
Bottom 9 | C | C pyro channel common connection to battery |
EasyMega provides explicit support for an external pyro +battery. All that is required is to remove the jumper +between the lipo terminal (Bottom 3) and the pyro terminal +(Bottom 2). Then hook the negative pyro battery terminal to ground +(Bottom 1) and the positive pyro battery to the pyro battery +input (Bottom 2). You can then use the existing pyro screw +terminals to hook up all of the pyro charges.
Because EasyMega has built-in support for a separate pyro +battery, if you want to fly with just one battery running +both the computer and firing the charges, you need to +connect the flight computer battery to the pyro +circuit. EasyMega has two screw terminals for thisâhook a +wire from the Lipo terminal (Bottom 3) to the Pyro terminal +(Bottom 2).
As explained above, an external active switch requires three +connections, one to the positive battery terminal, one to +the flight computer positive input and one to ground.
The positive battery terminal is available on Top terminal +1, the positive flight computer input is on Top terminal +2. Ground is on Top terminal 3.
A typical installation involves attaching +only a suitable battery, a single pole switch for +power on/off, and two pairs of wires connecting e-matches for the +apogee and main ejection charges. All Altus Metrum products are +designed for use with single-cell batteries with 3.7 volts +nominal. +EasyMini may also be used with other +batteries as long as they supply between 4 and 12 volts.
The battery connectors are a standard 2-pin JST connector; you +can purchase suitable batteries from the any vendor selling +Altus Metrum products. These batteries are +single-cell Lithium Polymer batteries that nominally provide 3.7 +volts. Other vendors sell similar batteries for RC aircraft +using mating connectors, however the polarity for those is +generally reversed from the batteries used by Altus Metrum +products. In particular, the Tenergy batteries supplied for use +in Featherweight flight computers are not compatible with Altus +Metrum flight computers or battery chargers.
Check polarity and voltage before connecting any battery not +purchased from Altus Metrum.
Spark Fun sells batteries that have a matching connector with +the correct polarity. However, these batteries include an +integrated current limiting circuit. That circuit will cause +the battery to shut down when firing the igniter circuit. Do +not use these batteries unless you remove the current limiting +circuit.
By default, we use the unregulated output of the battery +directly to fire ejection charges. This works marvelously +with standard low-current e-matches like the J-Tek from MJG +Technologies, and with Quest Q2G2 igniters. However, if you +want or need to use a separate pyro battery, check out +Section 3.8, âUsing a Separate Pyro Batteryâ for instructions on how to wire +that up. The altimeters are designed to work with an external +pyro battery of no more than 15 volts.
Ejection charges are wired directly to the screw terminal block +at the aft end of the altimeter. Youâll need a very small straight +blade screwdriver for these screws, such as you might find in a +jewelerâs screwdriver set.
Except for TeleMini v1.0, the flight computers also use the +screw terminal block for the power switch leads. On TeleMini v1.0, +the power switch leads are soldered directly to the board and +can be connected directly to a switch.
For most air-frames, the integrated antennas are more than +adequate. However, if you are installing in a carbon-fiber or +metal electronics bay which is opaque to RF signals, you may need to +use off-board external antennas instead. In this case, you can +replace the stock UHF antenna wire with an edge-launched SMA connector, +and, on TeleMetrum v1, you can unplug the integrated GPS +antenna and select an appropriate off-board GPS antenna with +cable terminating in a U.FL connector.
In the US, you need an +amateur radio license +or other authorization to legally operate the radio +transmitters that are part of our products.
In the rocket itself, you just need a flight computer +and a single-cell, 3.7 volt nominal Li-Po rechargeable +battery. +An 850mAh battery weighs less than a 9V +alkaline battery, and will run a TeleMetrum, TeleMega +or EasyMega for hours. +A 110mAh battery weighs less +than a triple A battery and is a good choice for use +with +TeleMini or +EasyMini.
By default, we ship TeleMini, TeleMetrum and TeleMega +flight computers with a simple wire antenna. If your +electronics bay or the air-frame it resides within is +made of carbon fiber, which is opaque to RF signals, +you may prefer to install an SMA connector so that you +can run a coaxial cable to an antenna mounted +elsewhere in the rocket. However, note that the GPS +antenna is fixed on all current products, so you +really want to install the flight computer in a bay +made of RF-transparent materials if at all possible.
To receive the data stream from the rocket, you need +an antenna and short feed-line connected to one of our +TeleDongle +units. If possible, use an SMA to BNC adapter instead +of feedline between the antenna feedpoint and +TeleDongle, as this will give you the best +performance. The TeleDongle in turn plugs directly +into the USB port on a notebook computer. Because +TeleDongle looks like a simple serial port, your +computer does not require special device +drivers⦠just plug it in.
The GUI tool, AltosUI, is written in Java and runs +across Linux, Mac OS and Windows. Thereâs also a suite +of C tools for Linux which can perform most of the +same tasks.
Alternatively, a TeleBT attached with an SMA to BNC +adapter at the feed point of a hand-held yagi used in +conjunction with an Android device running AltosDroid +makes an outstanding ground station.
After the flight, +you can use the radio link to +extract the more detailed data logged in either +TeleMetrum or TeleMini devices, or +you can use a +USB cable to plug into the flight computer board directly. +A USB cable is also how you +charge the Li-Po battery, so youâll want one of those +anyway. The same cable used by lots of digital +cameras and other modern electronic stuff will work +fine.
If your rocket lands out of sight, you may enjoy +having a hand-held GPS receiver, so that you can put +in a way-point for the last reported rocket position +before touch-down. This makes looking for your rocket +a lot like Geo-Caching⦠just go to the way-point and +look around starting from there. AltosDroid on an +Android device with GPS receiver works great for this, +too!
You may also enjoy having a ham radio âHTâ that covers +the 70cm band⦠you can use that with your antenna to +direction-find the rocket on the ground the same way +you can use a Walston or Beeline tracker. This can be +handy if the rocket is hiding in sage brush or a tree, +or if the last GPS position doesnât get you close +enough because the rocket dropped into a canyon, or +the wind is blowing it across a dry lake bed, or +something like that⦠Keith currently uses a Yaesu +FT1D, Bdale has a Yaesu VX-7R, which is a nicer radio +in most ways but doesnât support APRS.
So, to recap, on the ground the hardware youâll need includes:
The best hand-held commercial directional antennas weâve found for radio +direction finding rockets are from +Arrow Antennas.
The 440-3 and 440-5 are both good choices for finding +a TeleMetrum- or TeleMini- equipped rocket when used +with a suitable 70cm HT. TeleDongle and an SMA to BNC +adapter fit perfectly between the driven element and +reflector of Arrow antennas.
Our software makes it easy to log the data from each +flight, both the telemetry received during the flight +itself, and the more complete data log recorded in the +flash memory on the altimeter board. Once this data +is on your computer, our post-flight tools make it +easy to quickly get to the numbers everyone wants, +like apogee altitude, max acceleration, and max +velocity. You can also generate and view a standard +set of plots showing the altitude, acceleration, and +velocity of the rocket during flight. And you can +even export a flight log in a format usable with Google +Maps and Google Earth for visualizing the flight path +in two or three dimensions!
Our ultimate goal is to emit a set of files for each +flight that can be published as a web page per flight, +or just viewed on your local disk with a web browser.
We have designed and prototyped several âcompanion +boardsâ that can attach to the companion connector on +TeleMetrum, TeleMega and EasyMega flight computers to +collect more data, provide more pyro channels, and so +forth. We do not yet know if or when any of these +boards will be produced in enough quantity to sell. +If you have specific interests for data collection or +control of events in your rockets beyond the +capabilities of our existing productions, please let +us know!
Because all of our work is open, both the hardware +designs and the software, if you have some great idea +for an addition to the current Altus Metrum family, +feel free to dive in and help! Or let us know what +youâd like to see that we arenât already working on, +and maybe weâll get excited about it tooâ¦
Watch our web site for +more news and information as our family of products +evolves!
The AltosUI program provides a graphical user interface for +interacting with the Altus Metrum product family. AltosUI can +monitor telemetry data, configure devices and many other +tasks. The primary interface window provides a selection of +buttons, one for each major activity in the system. This +chapter is split into sections, each of which documents one of +the tasks provided from the top-level toolbar.
Selecting this item brings up a dialog box listing all +of the connected TeleDongle devices. When you choose +one of these, AltosUI will create a window to display +telemetry data as received by the selected TeleDongle +device.
All telemetry data received are automatically recorded +in suitable log files. The name of the files includes +the current date and rocket serial and flight numbers.
The radio frequency being monitored by the TeleDongle +device is displayed at the top of the window. You can +configure the frequency by clicking on the frequency +box and selecting the desired frequency. AltosUI +remembers the last frequency selected for each +TeleDongle and selects that automatically the next +time you use that device.
Below the TeleDongle frequency selector, the window +contains a few significant pieces of information about +the altimeter providing the telemetry data stream:
Finally, the largest portion of the window contains a +set of tabs, each of which contain some information +about the rocket. Theyâre arranged in flight order +so that as the flight progresses, the selected tab +automatically switches to display data relevant to the +current state of the flight. You can select other tabs +at any time. The final table tab displays all of the +raw telemetry values in one place in a +spreadsheet-like format.
The Launch Pad tab shows information used to decide when the +rocket is ready for flight. The first elements include red/green +indicators, if any of these is red, youâll want to evaluate +whether the rocket is ready to launch:
The Launchpad tab also shows the computed launch pad +position and altitude, averaging many reported +positions to improve the accuracy of the fix.
This tab is shown during Boost, Fast and Coast +phases. The information displayed here helps monitor the +rocket as it heads towards apogee.
The height, speed, acceleration and tilt are shown along +with the maximum values for each of them. This allows you to +quickly answer the most commonly asked questions youâll hear +during flight.
The current latitude and longitude reported by the GPS are +also shown. Note that under high acceleration, these values +may not get updated as the GPS receiver loses position +fix. Once the rocket starts coasting, the receiver should +start reporting position again.
Finally, the current igniter voltages are reported as in the +Launch Pad tab. This can help diagnose deployment failures +caused by wiring which comes loose under high acceleration.
Once the rocket has reached apogee and (we hope) +activated the apogee charge, attention switches to +tracking the rocket on the way back to the ground, and +for dual-deploy flights, waiting for the main charge +to fire.
To monitor whether the apogee charge operated +correctly, the current descent rate is reported along +with the current height. Good descent rates vary based +on the choice of recovery components, but generally +range from 15-30m/s on drogue and should be below +10m/s when under the main parachute in a dual-deploy +flight.
With GPS-equipped flight computers, you can locate the +rocket in the sky using the elevation and bearing +information to figure out where to look. Elevation is +in degrees above the horizon. Bearing is reported in +degrees relative to true north. Range can help figure +out how big the rocket will appear. Ground Distance +shows how far it is to a point directly under the +rocket and can help figure out where the rocket is +likely to land. Note that all of these values are +relative to the pad location. If the elevation is near +90°, the rocket is over the pad, not over you.
Finally, the igniter voltages are reported in this tab +as well, both to monitor the main charge as well as to +see what the status of the apogee charge is. Note +that some commercial e-matches are designed to retain +continuity even after being fired, and will continue +to show as green or return from red to green after +firing.
Once the rocket is on the ground, attention switches +to recovery. While the radio signal is often lost once +the rocket is on the ground, the last reported GPS +position is generally within a short distance of the +actual landing location.
The last reported GPS position is reported both by +latitude and longitude as well as a bearing and +distance from the launch pad. The distance should give +you a good idea of whether to walk or hitch a ride. +Take the reported latitude and longitude and enter +them into your hand-held GPS unit and have that +compute a track to the landing location.
Our flight computers will continue to transmit RDF +tones after landing, allowing you to locate the rocket +by following the radio signal if necessary. You may +need to get away from the clutter of the flight line, +or even get up on a hill (or your neighborâs RV roof) +to receive the RDF signal.
The maximum height, speed and acceleration reported +during the flight are displayed for your admiring +observers. The accuracy of these immediate values +depends on the quality of your radio link and how many +packets were received. Recovering the on-board data +after flight may yield more precise results.
To get more detailed information about the flight, you +can click on the Graph Flight button which will +bring up a graph window for the current flight.
The table view shows all of the data available from the +flight computer. Probably the most useful data on +this tab is the detailed GPS information, which includes +horizontal dilution of precision information, and +information about the signal being received from the satellites.
When the TeleMetrum has a GPS fix, the Site Map tab +will map the rocketâs position to make it easier for +you to locate the rocket, both while it is in the air, +and when it has landed. The rocketâs state is +indicated by color: white for pad, red for boost, pink +for fast, yellow for coast, light blue for drogue, +dark blue for main, and black for landed.
The mapâs default scale is approximately 3m (10ft) per +pixel. The map can be dragged using the left mouse +button. The map will attempt to keep the rocket +roughly centered while data is being received.
You can adjust the style of map and the zoom level +with buttons on the right side of the map window. You +can draw a line on the map by moving the mouse over +the map with a button other than the left one pressed, +or by pressing the left button while also holding down +the shift key. The length of the line in real-world +units will be shown at the start of the line.
Images are fetched automatically via the Google Maps +Static API, and cached on disk for reuse. If map +images cannot be downloaded, the rocketâs path will be +traced on a dark gray background instead.
You can pre-load images for your favorite launch sites +before you leave home; check out Section 11.12, âLoad Mapsâ.
TeleMega includes four additional programmable pyro +channels. The Ignitor tab shows whether each of them has +continuity. If an ignitor has a low resistance, then the +voltage measured here will be close to the pyro battery +voltage. A value greater than 3.2V is required for a GO +status.
The altimeter records flight data to its internal +flash memory. +Data logged on board is recorded at a much +higher rate than the telemetry system can handle, and +is not subject to radio drop-outs. As such, it +provides a more complete and precise record of the +flight. +The Save Flight Data button allows you to +read the flash memory and write it to disk.
Clicking on the Save Flight Data button brings up a +list of connected flight computers and TeleDongle +devices. If you select a flight computer, the flight +data will be downloaded from that device directly. +If you select a TeleDongle device, flight data will be +downloaded from a flight computer over radio link via +the specified TeleDongle. See +Section A.3, âControlling An Altimeter Over The Radio Linkâ for +more information.
After the device has been selected, a dialog showing +the flight data saved in the device will be shown +allowing you to select which flights to download and +which to delete. With version 0.9 or newer firmware, +you must erase flights in order for the space they +consume to be reused by another flight. This prevents +accidentally losing flight data if you neglect to +download data before flying again. Note that if there +is no more space available in the device, then no data +will be recorded during the next flight.
The file name for each flight log is computed +automatically from the recorded flight date, altimeter +serial number and flight number information.
Select this button and you are prompted to select a flight +record file, either a .telem file recording telemetry data or a +.eeprom file containing flight data saved from the altimeter +flash memory.
Once a flight record is selected, the flight monitor interface +is displayed and the flight is re-enacted in real +time. +Check +Section 11.1, âMonitor Flightâ to learn how this window operates.
Select this button and you are prompted to select a flight +record file, either a .telem file recording telemetry data or a +.eeprom file containing flight data saved from +flash memory.
Note that telemetry files will generally produce poor graphs +due to the lower sampling rate and missed telemetry packets. +Use saved flight data in .eeprom files for graphing where possible.
Once a flight record is selected, a window with multiple tabs is +opened.
By default, the graph contains acceleration (blue), +velocity (green) and altitude (red).
The graph can be zoomed into a particular area by +clicking and dragging down and to the right. Once +zoomed, the graph can be reset by clicking and +dragging up and to the left. Holding down control and +clicking and dragging allows the graph to be panned. +The right mouse button causes a pop-up menu to be +displayed, giving you the option save or print the +plot.
This selects which graph elements to show, and, at the +very bottom. It also lets you configure how +the graph is drawn:
Shows overall data computed from the flight.
This tool takes the raw data files and makes them +available for external analysis. When you select this +button, you are prompted to select a flight data file, +which can be either a .eeprom or .telem. The .eeprom +files contain higher resolution and more continuous +data, while .telem files contain receiver signal +strength information. Next, a second dialog appears +which is used to select where to write the resulting +file. +It has a selector to choose between CSV and KML +file formats.
This is a text file containing the data in a form +suitable for import into a spreadsheet or other +external data analysis tool. The first few lines of +the file contain the version and configuration +information from the altimeter, then there is a single +header line which labels all of the fields. All of +these lines start with a # character which many +tools can be configured to skip over.
The remaining lines of the file contain the data, with +each field separated by a comma and at least one +space. All of the sensor values are converted to +standard units, with the barometric data reported in +both pressure, altitude and height above pad units.
Select this button and then select either an altimeter or +TeleDongle Device from the list provided. Selecting a TeleDongle +device will use the radio link to configure a remote +altimeter.
The first few lines of the dialog provide information about the +connected device, including the product name, +software version and hardware serial number. Below that are the +individual configuration entries.
At the bottom of the dialog, there are four buttons:
The rest of the dialog contains the parameters to be configured.
This sets the altitude (above the recorded pad +altitude) at which the main igniter will fire. The +drop-down menu shows some common values, but you can +edit the text directly and choose whatever you +like. If the apogee charge fires below this altitude, +then the main charge will fire two seconds after the +apogee charge fires.
When flying redundant electronics, itâs often +important to ensure that multiple apogee charges donât +fire at precisely the same time, as that can over +pressurize the apogee deployment bay and cause a +structural failure of the air-frame. The Apogee Delay +parameter tells the flight computer to fire the apogee +charge a certain number of seconds after apogee has +been detected.
Apogee lockout is the number of seconds after boost +where the flight computer will not fire the apogee +charge, even if the rocket appears to be at +apogee. This is often called Mach Delay, as it is +intended to prevent a flight computer from +unintentionally firing apogee charges due to the +pressure spike that occurrs across a mach +transition. Altus Metrum flight computers include a +Kalman filter which is not fooled by this sharp +pressure increase, and so this setting should be left +at the default value of zero to disable it.
This configures which of the frequencies to use for +both telemetry and packet command mode. Note that if +you set this value via packet command mode, the +TeleDongle frequency will also be automatically +reconfigured to match so that communication will +continue afterwards.
The radios in every Altus Metrum device are calibrated +at the factory to ensure that they transmit and +receive on the specified frequency. If you need to +you can adjust the calibration by changing this value. +Do not do this without understanding what the value +means, read the appendix on calibration and/or the +source code for more information. To change a +TeleDongleâs calibration, you must reprogram the unit +completely.
Enables the radio for transmission during +flight. When disabled, the radio will not +transmit anything during flight at all.
This sets the modulation bit rate for data +transmission for both telemetry and packet +link mode. Lower bit rates will increase range +while reducing the amount of data that can be +sent and increasing battery consumption. All +telemetry is done using a rate 1/2 constraint +4 convolution code, so the actual data +transmission rate is 1/2 of the modulation bit +rate specified here.
How often to transmit GPS information via APRS +(in seconds). When set to zero, APRS +transmission is disabled. +This option is +available on TeleMetrum v2 and TeleMega +boards. TeleMetrum v1 boards cannot transmit +APRS packets. +Note that a single APRS packet +takes nearly a full second to transmit, so +enabling this option will prevent sending any +other telemetry during that time.
Which SSID to report in APRS packets. By +default, this is set to the last digit of the +serial number, but can be configured to any +value from 0 to 9.
Whether to send APRS data in Compressed or +Uncompressed format. Compressed format is +smaller and more precise. Uncompressed +format is older, but may work better with your +device. The Kenwood TH-D72 only displays +altitude information with Uncompressed +format, while the Yaesu FT1D only displays +altitude with Compressed format. Test before +you fly to see which to use.
This sets the call sign included in each +telemetry packet. Set this as needed to +conform to your local radio regulations.
This sets the space (in kilobytes) allocated +for each flight log. The available space will +be divided into chunks of this size. A smaller +value will allow more flights to be stored, a +larger value will record data from longer +flights.
This configuration parameter allows the two standard ignitor +channels (Apogee and Main) to be used in different +configurations.
Because they include accelerometers, +TeleMetrum, TeleMega and EasyMega are +sensitive to the orientation of the board. By +default, they expect the antenna end to point +forward. This parameter allows that default to +be changed, permitting the board to be mounted +with the antenna pointing aft instead.
The beeper on all Altus Metrum flight +computers works best at 4000Hz, however if you +have more than one flight computer in a single +airframe, having all of them sound at the same +frequency can be confusing. This parameter +lets you adjust the base beeper frequency +value.
This sets the amount of motion that TeleGPS +needs to see before logging the new +position. Motions smaller than this are +skipped, which saves storage space.
The interval between TeleGPS position reports, +both over the air and in the log. Increase +this to reduce the frequency of radio +transmissions and the length of time available +in the log.
This opens a separate window to recalibrate the +accelerometers. Follow the instructions, orienting the +flight computer with the antenna end, or end opposite +the screw terminals, in the case of EasyMega, first up +and then down.
When the calibration is complete, return to the +Configure Altimeter window and save the new +calibration values.
This opens a separate window to configure the +additional pyro channels available on TeleMega +and EasyMega. One column is presented for +each channel. Each row represents a single +parameter, if enabled the parameter must meet +the specified test for the pyro channel to be +fired.
Select conditions and set the related value; +the pyro channel will be activated when all +of the conditions are met. Each pyro channel +has a separate set of configuration values, so +you can use different values for the same +condition with different channels.
At the bottom of the window, the Pyro Firing +Time configuration sets the length of time +(in seconds) which each of these pyro channels +will fire for.
Once you have selected the appropriate +configuration for all of the necessary pyro +channels, you can save the pyro configuration +along with the rest of the flight computer +configuration by pressing the Save button in +the main Configure Flight Computer window.
Because this value is computed by integrating +rate gyros, it gets progressively less +accurate as the flight goes on. It should have +an accumulated error of less than 0.2°/second +(after 10 seconds of flight, the error should +be less than 2°).
The usual use of the orientation configuration +is to ensure that the rocket is traveling +mostly upwards when deciding whether to ignite +air starts or additional stages. For that, +choose a reasonable maximum angle (like 20°) +and set the motor igniter to require an angle +of less than that value.
+The flight software tracks the flight +through a sequence of states: +
You can select a state to limit when the pyro channel may activate; +note that the check is based on when the rocket transitions into the +state, and so checking for âgreater than Boostâ means that the rocket +is currently in boost or some later state.
When a motor burns out, the rocket enters either Fast or Coast state +(depending on how fast it is moving). If the computer detects upwards +acceleration again, it will move back to Boost state.
This button presents a dialog so that you can +configure the AltosUI global settings.
AltosUI provides voice announcements during +flight so that you can keep your eyes on the +sky and still get information about the +current flight status. However, sometimes you +donât want to hear them.
AltosUI logs all telemetry data and saves all +flash data to this directory. This +directory is also used as the staring point +when selecting data files for display or +export.
Click on the directory name to bring up a +directory choosing dialog, select a new +directory and click Select Directory to +change where AltosUI reads and writes data +files.
This value is transmitted in each command +packet sent from TeleDongle and received from +an altimeter. It is not used in telemetry +mode, as the callsign configured in the +altimeter board is included in all telemetry +packets. Configure this with the AltosUI +operators call sign as needed to comply with +your local radio regulations.
Note that to successfully command a flight +computer over the radio (to configure the +altimeter, monitor idle, or fire pyro +charges), the callsign configured here must +exactly match the callsign configured in the +flight computer. This matching is case +sensitive.
This switches between metric units (meters) +and imperial units (feet and miles). This +affects the display of values use during +flight monitoring, configuration, data +graphing and all of the voice +announcements. It does not change the units +used when exporting to CSV files, those are +always produced in metric units.
This causes all communication with a connected +device to be dumped to the console from which +AltosUI was started. If youâve started it from +an icon or menu entry, the output will simply +be discarded. This mode can be useful to debug +various serial communication issues.
Selects the set of fonts used in the flight +monitor window. Choose between the small, +medium and large sets.
Switches between the available Java user +interface appearances. The default selection +is supposed to match the native window system +appearance for the target platform.
Selects the initial position for the main +AltosUI window that includes all of the +command buttons.
Sets the number of map tiles kept in memory +while the application is running. More tiles +consume more memory, but will make panning +around the map faster.
This brings up a dialog where you can +configure the set of frequencies shown in the +various frequency menus. You can add as many +as you like, or even reconfigure the default +set. Changing this list does not affect the +frequency settings of any devices, it only +changes the set of frequencies shown in the +menus.
Select this button and then select a TeleDongle or +TeleBT Device from the list provided.
The first few lines of the dialog provide information +about the connected device, including the product +name, software version and hardware serial +number. Below that are the individual configuration +entries.
Note that TeleDongle and TeleBT donât save any +configuration data, the settings here are recorded on +the local machine in the Java preferences +database. Moving the device to another machine, or +using a different user account on the same machine +will cause settings made here to have no effect.
At the bottom of the dialog, there are three +buttons:
The rest of the dialog contains the parameters +to be configured.
This configures the frequency to use for both +telemetry and packet command mode. Set this +before starting any operation involving packet +command mode so that it will use the right +frequency. Telemetry monitoring mode also +provides a menu to change the frequency, and +that menu also sets the same Java preference +value used here.
The radios in every Altus Metrum device are +calibrated at the factory to ensure that they +transmit and receive on the specified +frequency. To change a TeleDongle or TeleBTâs +calibration, you must reprogram the unit +completely, so this entry simply shows the +current value and doesnât allow any changes.
This reprograms Altus Metrum devices with new +firmware. +TeleMetrum v1.x, TeleDongle v0.2, TeleMini v1.0 +and TeleBT v1.0 are all reprogrammed by using another +similar unit as a programming dongle (pair +programming). +TeleMega, EasyMega, TeleMetrum v2, +EasyMini and TeleDongle v3 are all +programmed directly +over USB (self programming). Please read +the directions for flashing devices in +Appendix C, Updating Device Firmware.
This activates the igniter circuits in the flight +computer to help test recovery systems +deployment. +Because this command can operate over the +Packet Command Link, you can prepare the rocket as for +flight and then test the recovery system without +needing to snake wires inside the air-frame.
Selecting the Fire Igniter button brings up the +usual device selection dialog. Pick the desired +device. This brings up another window which shows the +current continuity test status for all of the pyro +channels.
Next, select the desired igniter to fire. This will +enable the Arm button.
Select the Arm button. This enables the Fire +button. The word Arm is replaced by a countdown +timer indicating that you have 10 seconds to press the +Fire button or the system will deactivate, at which +point you start over again at selecting the desired +igniter.
This listens for telemetry packets on all of the +configured frequencies, displaying information about +each device it receives a packet from. You can select +which of the baud rates and telemetry formats should +be tried; by default, it only listens at 38400 baud +with the standard telemetry format used in v1.0 and +later firmware.
Before heading out to a new launch site, you can use +this to load satellite images in case you donât have +internet connectivity at the site.
Thereâs a drop-down menu of launch sites we know +about; if your favorites arenât there, please let us +know the lat/lon and name of the site. The contents of +this list are actually downloaded from our server at +run-time, so as new sites are sent in, theyâll get +automatically added to this list. If the launch site +isnât in the list, you can manually enter the lat/lon +values
There are four different kinds of maps you can view; +you can select which to download by selecting as many +as you like from the available types:
You can specify the range of zoom levels to download; +smaller numbers show more area with less +resolution. The default level, 0, shows about +3m/pixel. One zoom level change doubles or halves that +number. Larger zoom levels show more detail, smaller +zoom levels less.
The Map Radius value sets how large an area around the +center point to download. Select a value large enough +to cover any plausible flight from that site. Be aware +that loading a large area with a high maximum zoom +level can attempt to download a lot of data. Loading +hybrid maps with a 10km radius at a minimum zoom of -2 +and a maximum zoom of 2 consumes about 120MB of +space. Terrain and road maps consume about 1/10 as +much space as satellite or hybrid maps.
Clicking the Load Map button will fetch images from +Google Maps; note that Google limits how many images +you can fetch at once, so if you load more than one +launch site, you may get some gray areas in the map +which indicate that Google is tired of sending data to +you. Try again later.
This brings up a dialog similar to the Monitor Flight +UI, except it works with the altimeter in âidleâ mode +by sending query commands to discover the current +state rather than listening for telemetry +packets. Because this uses command mode, it needs to +have the TeleDongle and flight computer callsigns +match exactly. If you can receive telemetry, but +cannot manage to run Monitor Idle, then itâs very +likely that your callsigns are different in some way.
You can change the frequency and callsign used to +communicate with the flight computer; they must both +match the configuration in the flight computer +exactly.
AltosDroid provides the same flight monitoring capabilities as +AltosUI, but runs on Android devices. AltosDroid is designed +to connect to a TeleBT receiver over Bluetooth⢠and (on +Android devices supporting USB On-the-go) TeleDongle and +TeleBT devices over USB. AltosDroid monitors telemetry data, +logging it to internal storage in the Android device, and +presents that data in a UI similar to the Monitor Flight +window in AltosUI.
This manual will explain how to configure AltosDroid, connect +to TeleBT or TeleDongle, operate the flight monitoring +interface and describe what the displayed data means.
AltosDroid is available from the Google Play store. To +install it on your Android device, open the Google +Play Store application and search for +âaltosdroidâ. Make sure you donât have a space between +âaltosâ and âdroidâ or you probably wonât find what +you want. That should bring you to the right page from +which you can download and install the application.
Before using TeleBT with AltosDroid, make sure the +internal TeleBT battery is charged. To do this, +attach a micro USB cable from a computer or other USB +power source to TeleBT. A dual LED on the circuit +board should illuminate, showing red while the battery +is charging, green when charging is completed, and +both red and green on at the same time if there is a +battery fault.
Press the Android Menu button or soft-key to see the +configuration options available. Select the Connect a +device option and then the Scan for devices entry +at the bottom to look for your TeleBT device. Select +your device, and when it asks for the code, enter +1234.
Subsequent connections will not require you to enter +that code, and your paired device will appear in the +list without scanning.
Get a special USB On-the-go adapter cable. These +cables have a USB micro-B male connector on one end +and a standard A female connector on the other +end. Plug in your TeleDongle or TeleBT device to the +adapter cable and the adapter cable into your phone +and AltosDroid should automatically start up. If it +doesnât, the most likely reason is that your Android +device doesnât support USB On-the-go.
The main AltosDroid menu has a selection of operation +and configuration options.
AltosDroid is designed to mimic the AltosUI flight +monitoring display, providing separate tabs for each +stage of your rocket flight along with a tab +containing a map of the local area with icons marking +the current location of the altimeter and the Android +device.
The Pad tab shows information used to decide when +the rocket is ready for flight. The first elements +include red/green indicators, if any of these is red, +youâll want to evaluate whether the rocket is ready to +launch.
When the pad tab is selected, the voice responses will +include status changes to the igniters and GPS +reception, letting you know if the rocket is still +ready for launch.
The Pad tab also shows the location of the Android +device.
The Flight tab shows information used to evaluate +and spot a rocket while in flight. It displays speed +and height data to monitor the health of the rocket, +along with elevation, range and bearing to help locate +the rocket in the sky.
While the Flight tab is displayed, the voice +announcements will include current speed, height, +elevation and bearing information.
The Recover tab shows information used while +recovering the rocket on the ground after flight.
While the Recover tab is displayed, the voice +announcements will include distance along with either +bearing or direction, depending on whether you are +moving.
The Map tab shows a map of the area around the +rocket being tracked along with information needed to +recover it.
On the map itself, icons showing the location of the +android device along with the last known location of +each tracker. A blue line is drawn from the android +device location to the currently selected tracker.
Below the map, the distance and either bearing or +direction along with the lat/lon of the target and the +android device are shown
The Map tab provides the same voice announcements as +the Recover tab.
AltosDroid always saves every bit of telemetry data it +receives. To download that to a computer for use with +AltosUI, remove the SD card from your Android device, +or connect your device to your computerâs USB port and +browse the files on that device. You will find +.telem files in the TeleMetrum directory that will +work with AltosUI directly.
The AltOS firmware build for the altimeters has two +fundamental modes, âidleâ and âflightâ. Which of these modes +the firmware operates in is determined at start up +time. +For +TeleMetrum, TeleMega and EasyMega, which have accelerometers, the mode is +controlled by the orientation of the +rocket (well, actually the board, of courseâ¦) at the time +power is switched on. If the rocket is ânose upâ, then +the flight computer assumes itâs on a rail or rod being prepared for +launch, so the firmware chooses flight mode. However, if the +rocket is more or less horizontal, the firmware instead enters +idle mode. +Since +EasyMini doesnât +have an +accelerometer we can use to determine orientation, âidleâ mode +is selected if the board is connected via USB to a computer, +otherwise the board enters âflightâ mode. +TeleMini +selects âidleâ mode if it receives a command packet +within the +first five seconds of operation.
At power on, the altimeter will beep out the battery voltage +to the nearest tenth of a volt. Each digit is represented by +a sequence of short âditâ beeps, with a pause between +digits. A zero digit is represented with one long âdahâ +beep. Then there will be a short pause while the altimeter +completes initialization and self test, and decides which mode +to enter next.
In flight or âpadâ mode, the altimeter engages the flight +state machine, goes into transmit-only mode to send telemetry, +and waits for launch to be detected. Flight mode is indicated +by an âdi-dah-dah-ditâ (âPâ for pad) on the beeper or lights, +followed by beeps or flashes indicating the state of the +pyrotechnic igniter continuity. One beep/flash indicates +apogee continuity, two beeps/flashes indicate main continuity, +three beeps/flashes indicate both apogee and main continuity, +and one longer âbrapâ sound which is made by rapidly +alternating between two tones indicates no continuity. For a +dual deploy flight, make sure youâre getting three beeps or +flashes before launching! For apogee-only or motor eject +flights, do what makes sense.
If idle mode is entered, you will hear an audible âdi-ditâ or +see two short flashes (âIâ for idle), and the flight state +machine is disengaged, thus no ejection charges will fire. +The altimeters also listen for the radio link when in idle +mode for requests sent via TeleDongle. Commands can be issued +in idle mode over either USB or the radio link +equivalently. +TeleMini only has the radio link. +Idle mode is useful for configuring the altimeter, for +extracting data from the on-board storage chip after +flight, and for ground testing pyro charges.
In âIdleâ and âPadâ modes, once the mode indication +beeps/flashes and continuity indication has been sent, if +there is no space available to log the flight in on-board +memory, the flight computer will emit a warbling tone (much +slower than the âno continuity toneâ)
See Section 3.5, âUnderstanding Beepsâ for a summary of all of +the audio signals used.
Once landed, the flight computer will signal that by emitting +the âLandedâ sound described above, after which it will beep +out the apogee height (in meters). Each digit is represented +by a sequence of short âditâ beeps, with a pause between +digits. A zero digit is represented with one long âdahâ +beep. The flight computer will continue to report landed mode +and beep out the maximum height until turned off.
One âneat trickâ of particular value when TeleMetrum, TeleMega +or EasyMega are used with +very large air-frames, is that you can power the board up while the +rocket is horizontal, such that it comes up in idle mode. Then you can +raise the air-frame to launch position, and issue a reset command +via TeleDongle over the radio link to cause the altimeter to reboot and +come up in flight mode. This is much safer than standing on the top +step of a rickety step-ladder or hanging off the side of a launch +tower with a screw-driver trying to turn on your avionics before +installing igniters!
TeleMini is configured solely via the radio link. Of course, that +means you need to know the TeleMini radio configuration values +or you wonât be able to communicate with it. For situations +when you donât have the radio configuration values, +TeleMini v1.0 +offers an emergency recovery mode. In this mode, +TeleMini v1.0 is +configured as follows:
To get into emergency recovery mode, first find the row of +four small holes opposite the switch wiring. Using a short +piece of small gauge wire, connect the outer two holes +together, then power TeleMini up. Once the red LED is lit, +disconnect the wire and the board should signal that itâs in +idle mode after the initial five second startup +period.
TeleMetrum and TeleMega include a complete GPS receiver. A +complete explanation of how GPS works is beyond the scope of +this manual, but the bottom line is that the GPS receiver +needs to lock onto at least four satellites to obtain a solid +3 dimensional position fix and know what time it is.
The flight computers provide backup power to the GPS chip any time a +battery is connected. This allows the receiver to âwarm startâ on +the launch rail much faster than if every power-on were a GPS +âcold startâ. In typical operations, powering up +on the flight line in idle mode while performing final air-frame +preparation will be sufficient to allow the GPS receiver to cold +start and acquire lock. Then the board can be powered down during +RSO review and installation on a launch rod or rail. When the board +is turned back on, the GPS system should lock very quickly, typically +long before igniter installation and return to the flight line are +complete.
One of the unique features of the Altus Metrum system is the +ability to create a two way command link between TeleDongle +and an altimeter using the digital radio transceivers +built into each device. This allows you to interact with the +altimeter from afar, as if it were directly connected to the +computer.
Any operation which can be performed with a flight computer can +either be done with the device directly connected to the +computer via the USB cable, or through the radio +link. TeleMini doesnât provide a USB connector and so it is +always communicated with over radio. Select the appropriate +TeleDongle device when the list of devices is presented and +AltosUI will interact with an altimeter over the radio link.
One oddity in the current interface is how AltosUI selects the +frequency for radio communications. Instead of providing +an interface to specifically configure the frequency, it uses +whatever frequency was most recently selected for the target +TeleDongle device in Monitor Flight mode. If you havenât ever +used that mode with the TeleDongle in question, select the +Monitor Flight button from the top level UI, and pick the +appropriate TeleDongle device. Once the flight monitoring +window is open, select the desired frequency and then close it +down again. All radio communications will now use that frequency.
Operation over the radio link for configuring an +altimeter, ground testing igniters, and so forth uses +the same RF frequencies as flight telemetry. To +configure the desired TeleDongle frequency, select the +monitor flight tab, then use the frequency selector +and close the window before performing other desired +radio operations.
The flight computers only enable radio commanding in +idle mode. TeleMetrum and TeleMega use the +accelerometer to detect which orientation they start +up in, so make sure you have the flight computer lying +horizontally when you turn it on. Otherwise, it will +start in pad mode ready for flight, and will not be +listening for command packets from TeleDongle.
TeleMini listens for a command packet for five seconds +after first being turned on, if it doesnât hear +anything, it enters pad mode, ready for flight and +will no longer listen for command packets. The easiest +way to connect to TeleMini is to initiate the command +and select the TeleDongle device. At this point, the +TeleDongle will be attempting to communicate with the +TeleMini. Now turn TeleMini on, and it should +immediately start communicating with the TeleDongle +and the desired operation can be performed.
You can monitor the operation of the radio link by watching the +lights on the devices. The red LED will flash each time a packet +is transmitted, while the green LED will light up on TeleDongle when +it is waiting to receive a packet from the altimeter.
An important aspect of preparing a rocket using electronic deployment +for flight is ground testing the recovery system. +Thanks +to the bi-directional radio link central to the Altus Metrum system, +this can be accomplished in a TeleMega, TeleMetrum or TeleMini equipped rocket +with less work than you may be accustomed to with other systems. It +can even be fun!
Just prep the rocket for flight, then power up the altimeter +in âidleâ +mode (placing air-frame horizontal for TeleMetrum or TeleMega, or +selecting the Configure Altimeter tab for TeleMini). +This will cause +the firmware to go into âidleâ mode, in which the normal flight +state machine is disabled and charges will not fire without +manual command. +You can now command the altimeter to fire the apogee +or main charges from a safe distance using your +computer and the Fire Igniter tab to complete ejection testing.
TeleMetrum, TeleMini and TeleMega all incorporate an +RF transceiver, but itâs not a full duplex system; +each end can only be transmitting or receiving at any +given moment. So we had to decide how to manage the +link.
By design, the altimeter firmware listens for the +radio link when itâs in âidle modeâ, which allows us +to use the radio link to configure the rocket, do +things like ejection tests, and extract data after a +flight without having to crack open the air-frame. +However, when the board is in âflight modeâ, the +altimeter only transmits and doesnât listen at all. +Thatâs because we want to put ultimate priority on +event detection and getting telemetry out of the +rocket through the radio in case the rocket crashes +and we arenât able to extract data later.
We donât generally use a normal packet radio mode +like APRS because theyâre just too inefficient. The +GFSK modulation we use is FSK with the base-band +pulses passed through a Gaussian filter before they go +into the modulator to limit the transmitted bandwidth. +When combined with forward error correction and +interleaving, this allows us to have a very robust +19.2 kilobit data link with only 10-40 milliwatts of +transmit power, a whip antenna in the rocket, and a +hand-held Yagi on the ground. Weâve had flights to +above 21k feet AGL with great reception, and +calculations suggest we should be good to well over +40k feet AGL with a 5-element yagi on the ground with +our 10mW units and over 100k feet AGL with the 40mW +devices. We hope to fly boards to higher altitudes +over time, and would of course appreciate customer +feedback on performance in higher altitude flights!
TeleMetrum v2.0 and TeleMega can send APRS if desired, and the +interval between APRS packets can be configured. As each APRS +packet takes a full second to transmit, we recommend an +interval of at least 5 seconds to avoid consuming too much +battery power or radio channel bandwidth. You can configure +the APRS interval using AltosUI; that process is described in +Section 11.6, âConfigure Altimeterâ.
AltOS supports both compressed and uncompressed APRS +position report data formats. The compressed format +provides for higher position precision and shorter +packets than the uncompressed APRS format. Weâve found +some older APRS receivers that do not handle the +compressed format. The Kenwood TH-72A requires the use +of uncompressed format to display altitude information +correctly. The Yaesu FT1D requires the use of +compressed format to display altitude information.
APRS packets include an SSID (Secondary Station Identifier) +field that allows one operator to have multiple +transmitters. AltOS allows you to set this to a single digit +from 0 to 9, allowing you to fly multiple transmitters at the +same time while keeping the identify of each one separate in +the receiver. By default, the SSID is set to the last digit of +the device serial number.
The APRS packet format includes a comment field that +can have arbitrary text in it. AltOS uses this to send +status information as shown in the following table.
Table A.1. Altus Metrum APRS Comments
Field | Example | Description |
---|---|---|
1 | L | GPS Status U for unlocked, L for locked |
2 | 6 | Number of Satellites in View |
3 | B4.0 | Altimeter Battery Voltage |
4 | A3.7 | Apogee Igniter Voltage |
5 | M3.7 | Main Igniter Voltage |
6 | 1286 | Device Serial Number |
4 | 1286 | Device Serial Number |
Hereâs an example of an APRS comment showing GPS lock with 6 +satellites in view, a primary battery at 4.0V, and +apogee and main igniters both at 3.7V from device 1286.
L6 B4.0 A3.7 M3.7 1286
Hereâs an example of an APRS comment showing GPS lock with 6 +satellites in view and a primary battery at 4.0V from device 1876.
L6 B4.0 1876
Make sure your primary battery is above 3.8V +any connected igniters are above 3.5V +and GPS is locked with at least 5 or 6 satellites in +view before flying. If GPS is switching between L and +U regularly, then it doesnât have a good lock and you +should wait until it becomes stable.
If the GPS receiver loses lock, the APRS data +transmitted will contain the last position for which +GPS lock was available. You can tell that this has +happened by noticing that the GPS status character +switches from L to U. Before GPS has locked, APRS +will transmit zero for latitude, longitude and +altitude.
Configuring an Altus Metrum altimeter for flight is +very simple. Even on our baro-only TeleMini and +EasyMini boards, the use of a Kalman filter means +there is no need to set a âmach delayâ. All of the +configurable parameters can be set using AltosUI. Read +Section 11.6, âConfigure Altimeterâ for more information.
All Altus Metrum products are sophisticated electronic devices. +When handled gently and properly installed in an air-frame, they +will deliver impressive results. However, as with all electronic +devices, there are some precautions you must take.
The Lithium Polymer rechargeable batteries have an +extraordinary power density. This is great because we can fly with +much less battery mass than if we used alkaline batteries or previous +generation rechargeable batteries⦠but if they are punctured +or their leads are allowed to short, they can and will release their +energy very rapidly! +Thus we recommend that you take some care when handling our batteries +and consider giving them some extra protection in your air-frame. We +often wrap them in suitable scraps of closed-cell packing foam before +strapping them down, for example.
The barometric sensors used on all of our flight computers are +sensitive to sunlight. In normal mounting situations, the baro sensor +and all of the other surface mount components +are âdownâ towards whatever the underlying mounting surface is, so +this is not normally a problem. Please consider this when designing an +installation in an air-frame with a see-through plastic payload bay. It +is particularly important to +consider this with TeleMini v1.0, both because the baro sensor is on the +âtopâ of the board, and because many model rockets with payload bays +use clear plastic for the payload bay! Replacing these with an opaque +cardboard tube, painting them, or wrapping them with a layer of masking +tape are all reasonable approaches to keep the sensor out of direct +sunlight.
The barometric sensor sampling port must be able to âbreatheâ, +both by not being covered by foam or tape or other materials that might +directly block the hole on the top of the sensor, and also by having a +suitable static vent to outside air.
As with all other rocketry electronics, Altus Metrum altimeters must +be protected from exposure to corrosive motor exhaust and ejection +charge gasses.
TeleMega, TeleMetrum v2, EasyMega, EasyMini and TeleDongle v3 +are all +programmed directly over their USB connectors (self +programming). +TeleMetrum v1, TeleMini v1.0 and TeleDongle v0.2 are +all programmed by using another device as a programmer (pair +programming). Itâs important to recognize which kind of devices +you have before trying to reprogram them.
You may wish to begin by ensuring you have current firmware +images. These are distributed as part of the AltOS software +bundle that also includes the AltosUI ground station program. +Newer ground station versions typically work fine with older +firmware versions, so you donât need to update your devices +just to try out new software features. You can always +download the most recent version from +http://www.altusmetrum.org/AltOS/
Self-programmable devices are reprogrammed by +connecting them to your computer over USB.
If the firmware loading fails, it can leave the device +unable to boot. Not to worry, you can force the device to +start the boot loader instead, which will let you try to +flash the device again.
On each device, connecting two pins from one of the exposed +connectors will force the boot loader to start, even if the +regular operating system has been corrupted in some way.
Once youâve located the right pins:
The board should now be visible over USB as +AltosFlash and be ready to receive firmware. Once +the board has been powered up, you can remove the +piece of wire.
The big concept to understand is that you have to use +a TeleMetrum v1.0, TeleBT v1.0 or TeleDongle v0.2 as a +programmer to update a pair programmed device. Due to +limited memory resources in the cc1111, we donât +support programming directly over USB for these +devices.
If you need to update the firmware on a TeleDongle +v0.2, we recommend updating the altimeter first, +before updating TeleDongle. However, note that +TeleDongle rarely need to be updated. Any firmware +version 1.0.1 or later will work, version 1.2.1 may +have improved receiver performance slightly.
If something goes wrong, give it another try.
Youâll need a special programming cable to +reprogram the TeleMini v1.0. You can make your own +using an 8-pin MicroMaTch connector on one end +and a set of four pins on the other.
If something goes wrong, give it another try.
Updating TeleDongle v0.2 firmware is just like +updating TeleMetrum v1.x or TeleMini v1.0 firmware, but you +use either a TeleMetrum v1.x, TeleDongle v0.2 or +TeleBT v1.0 as the programmer.
If something goes wrong, give it another try.
Be careful removing the programming cable from the +locking 8-pin connector on TeleMetrum. Youâll need a +fingernail or perhaps a thin screwdriver or knife +blade to gently pry the locking ears out slightly to +extract the connector. We used a locking connector on +TeleMetrum to help ensure that the cabling to +companion boards used in a rocket donât ever come +loose accidentally in flight.
Each flight computer logs data at 100 samples per second +during ascent and 10 samples per second during +descent, except for TeleMini v1.0, which records ascent at 10 samples +per second and descent at 1 sample per second. +Data are logged to +an on-board flash memory part, which can be partitioned into +several equal-sized blocks, one for each flight.
Table D.1. Data Storage on Altus Metrum altimeters
Device | Bytes per Sample | Total Storage | Minutes at Full Rate |
---|---|---|---|
TeleMetrum v1.0 | 8 | 1MB | 20 |
TeleMetrum v1.1 v1.2 | 8 | 2MB | 40 |
TeleMetrum v2.0 | 16 | 8MB | 80 |
TeleMini v1.0 | 2 | 5kB | 4 |
TeleMini v3.0 | 16 | 512kB | 5 |
EasyMini | 16 | 1MB | 10 |
TeleMega | 32 | 8MB | 40 |
EasyMega | 32 | 8MB | 40 |
The on-board flash is partitioned into separate flight logs, +each of a fixed maximum size. Increase the maximum size of +each log and you reduce the number of flights that can be +stored. Decrease the size and you can store more flights.
Configuration data is also stored in the flash memory on +TeleMetrum v1.x, +TeleMini v3.0 and +EasyMini. +This consumes 64kB +of flash space. This configuration space is not available +for storing flight log data.
TeleMetrum v2.0, TeleMega and EasyMega +store configuration data in a bit of eeprom available within +the processor chip, leaving that space available in flash for +more flight data.
To compute the amount of space needed for a single flight, you +can multiply the expected ascent time (in seconds) by 100 +times bytes-per-sample, multiply the expected descent time (in +seconds) by 10 times the bytes per sample and add the two +together. That will slightly under-estimate the storage (in +bytes) needed for the flight. +For instance, a TeleMetrum v2.0 flight spending +20 seconds in ascent and 150 seconds in descent will take +about (20 * 1600) + (150 * 160) = 56000 bytes of storage. You +could store dozens of these flights in the on-board flash.
The default size allows for several flights on each flight +computer, except for TeleMini v1.0, which +only holds data for a single flight. +You can adjust the size.
Altus Metrum flight computers will not overwrite existing +flight data, so be sure to download flight data and erase it +from the flight computer before it fills up. The flight +computer will still successfully control the flight even if it +cannot log data, so the only thing you will lose is the data.
Hereâs the full set of Altus Metrum products, both in +production and retired.
Table E.1. Altus Metrum Flight Computer Electronics
Device | Barometer | Z-axis accel | GPS | 3D sensors | Storage | RF Output | Battery |
---|---|---|---|---|---|---|---|
TeleMetrum v1.0 | MP3H6115 10km (33k') | MMA2202 50g | SkyTraq | - | 1MB | 10mW | 3.7V |
TeleMetrum v1.1 | MP3H6115 10km (33k') | MMA2202 50g | SkyTraq | - | 2MB | 10mW | 3.7V |
TeleMetrum v1.2 | MP3H6115 10km (33k') | ADXL78 70g | SkyTraq | - | 2MB | 10mW | 3.7V |
TeleMetrum v2.0 | MS5607 30km (100k') | MMA6555 102g | uBlox Max-7Q | - | 8MB | 40mW | 3.7V |
TeleMini v1.0 | MP3H6115 10km (33k') | - | - | - | 5kB | 10mW | 3.7V |
TeleMini v3.0 | MS5607 30km (100k') | - | - | - | 512kB | 40mW | 3.7V |
EasyMini v1.0 | MS5607 30km (100k') | - | - | - | 1MB | - | 3.7-12V |
TeleMega v1.0 | MS5607 30km (100k') | MMA6555 102g | uBlox Max-7Q | MPU6000 HMC5883 | 8MB | 40mW | 3.7V |
TeleMega v2.0 | MS5607 30km (100k') | MMA6555 102g | uBlox Max-7Q | MPU6000 HMC5883 | 8MB | 40mW | 3.7V |
EasyMega v1.0 | MS5607 30km (100k') | MMA6555 102g | - | MPU6000 HMC5883 | 8MB | - | 3.7V |
Table E.2. Altus Metrum Flight Computer Mechanical Components
Device | Connectors | Screw Terminals | Width | Length | Tube Size |
---|---|---|---|---|---|
TeleMetrum | Antenna Debug Companion USB Battery | Apogee pyro Main pyro Switch | 1 inch (2.54cm) | 2 ¾ inch (6.99cm) | 29mm coupler |
TeleMini v1.0 | Antenna Debug Battery | Apogee pyro Main pyro | ½ inch (1.27cm) | 1½ inch (3.81cm) | 18mm coupler |
TeleMini v2.0 | Antenna Debug USB Battery | Apogee pyro Main pyro Battery Switch | 0.8 inch (2.03cm) | 1½ inch (3.81cm) | 24mm coupler |
EasyMini | Debug USB Battery | Apogee pyro Main pyro Battery | 0.8 inch (2.03cm) | 1½ inch (3.81cm) | 24mm coupler |
TeleMega | Antenna Debug Companion USB Battery | Apogee pyro Main pyro Pyro A-D Switch Pyro battery | 1¼ inch (3.18cm) | 3¼ inch (8.26cm) | 38mm coupler |
EasyMega | Debug Companion USB Battery | Apogee pyro Main pyro Pyro A-D Switch Pyro battery | 1¼ inch (3.18cm) | 2¼ inch (5.62cm) | 38mm coupler |
Version 1.8.5 includes fixes to the ground software support +for TeleBT v4, along with a few other minor updates.
Version 1.8.4 includes support for EasyMini version 2.0
Version 1.8.3 includes support for TeleMega version 3.0 along +with two important flight computer fixes. This version also +changes KML export data to make Tripoli Record reporting +better and some updates to graph presentation and data +downloading.
Version 1.8.2 includes support for TeleGPS version 2.0 along +with accelerometer recalibration support in AltosUI.
1.8.2 also contains a couple of minor fixes for AltosUI when +analyzing saved data files.
Version 1.8.1 includes an important bug fix for Apogee Lockout +operation in all flight computers. Anyone using this option +must update firmware.
This release also contains a change in how flight computers +with accelerometers deal with speeds around and above Mach +1. In previous versions, the flight computer would completely +disregard the barometric sensor above 330m/s (around Mach +1). Now, the data from the barometric sensor is reduced in +effect without ever going away entirely. This prevents early +drogue deployment for flights which spend considerable time +above Mach 1.
1.8.1 also contains a couple of minor fixes for AltosUI when +analyzing saved data files.
AltOS Bug Fixes
AltosUI New Features
AltosUI Bug Fixes
Version 1.8 includes support for our new TeleBT v4.0 ground +station, updates for data analysis in our ground station +software and bug fixes in in the flight software for all our +boards and ground station interfaces.
AltosUI New Features
AltosUI Bug Fixes
Version 1.7 includes support for our new TeleMini v3.0 +flight computer and bug fixes in in the flight software for all our boards +and ground station interfaces.
AltOS New Features
AltOS Fixes
Version 1.6.8 fixes a TeleMega and TeleMetrum v2.0 bug where +the device could stop logging data and transmitting +telemetry in flight. All TeleMega v1.0, v2.0 and TeleMetrum +v2.0 users should update their flight firmware.
AltOS fixes:
AltOS changes:
AltosUI fixes:
Version 1.6.5 fixes a TeleMega and TeleMetrum v2.0 bug where +the device would often stop logging data and transmitting +telemetry in flight. All TeleMega v1.0, v2.0 and TeleMetrum +v2.0 users should update their flight firmware.
AltOS fixes:
Version 1.6.4 fixes a bluetooth communication problem with +TeleBT v1.0 devices, along with some altosui and altosdroid +minor nits. It also now ships firmware for some newer devices.
AltOS fixes:
AltosUI, TeleGPS and AltosDroid New Features:
AltosUI, TeleGPS and AltosDroid Fixes:
Version 1.6.3 adds idle mode to AltosDroid and has bug fixes +for our host software on desktops, laptops an android devices +along with BlueTooth support for Windows.
AltOS fixes:
AltosUI and TeleGPS New Features:
AltosUI and TeleGPS Fixes:
AltosDroid new features:
AltosDroid bug fixes:
Version 1.6.2 includes support for our updated TeleMega v2.0 +product and bug fixes in in the flight software for all our boards +and ground station interfaces.
AltOS New Features:
AltOS Fixes:
AltosUI and TeleGPS Fixes:
We spent a bunch of time trying to improve our documentation
Version 1.6.1 includes support for our updated TeleBT v3.0 +product and bug fixes in in the flight software for all our boards +and ground station interfaces.
AltOS New Features:
AltOS Fixes:
AltosUI and TeleGPS New Features:
AltosUI and TeleGPS Fixes:
AltosDroid New Features:
AltosDroid Fixes:
Version 1.6 includes support for our updated TeleDongle v3.0 +product and bug fixes in in the flight software for all our boards +and ground station interfaces.
AltOS New Features
AltOS Fixes
AltosUI and TeleGPS New Features
AltosUI Fixes
Version 1.5 is a major release. It includes support for our new +EasyMega product, new features and bug fixes in in the flight +software for all our boards and the AltosUI ground station
AltOS New Features
AltOS Fixes
AltosUI and TeleGPS New Features
AltosUI Fixes
Version 1.4.2 is a minor release. It fixes Java-related install issues on +Windows
Version 1.4.1 is a minor release. It fixes install issues on +Windows and provides the missing TeleMetrum V2.0 firmware. There +arenât any changes to the firmware or host applications at +all. All Windows users will want to upgrade to get the signed +driver, but Mac and Linux users who do not need the TeleMetrum +V2.0 firmware image will not need to upgrade.
Windows Install Fixes
Other Fixes
Version 1.4 is a major release. It includes support for our new +TeleGPS product, new features and bug fixes in in the flight +software for all our boards and the AltosUI ground station
AltOS new features:
AltOS fixes:
AltosUI new features:
AltosUI fixes:
Documentation changes:
Version 1.3.2 is a minor release. It includes small bug fixes for +the TeleMega flight software and AltosUI ground station
AltOS fixes:
AltosUI fixes:
Version 1.3.1 is a minor release. It improves support for +TeleMega, TeleMetrum v2.0, TeleMini v2.0 and EasyMini.
AltOS new features:
AltOS fixes:
AltosUI new features:
AltosUI fixes:
Version 1.3 is a major release. It adds support for TeleMega, +TeleMetrum v2.0, TeleMini v2.0 and EasyMini.
AltOS new features:
AltosUI new features:
AltosUI fixes:
Version 1.2.1 is a minor release. It adds support for TeleBT and +the AltosDroid application, provides several new features in +AltosUI and fixes some bugs in the AltOS firmware.
AltOS new features:
AltOS fixes:
AltosUI application new features:
AltosUI application fixes:
Version 1.2 is a major release. It adds support for MicroPeak +and the MicroPeak USB adapter.
AltOS New Features:
New Features:
AltosUI and MicroPeak fixes:
Version 1.1.1 is a bug-fix release. It fixes a couple of bugs +in AltosUI and one firmware bug that affects TeleMetrum +version 1.0 boards. Thanks to Bob Brown for help diagnosing +the Google Earth file export issue, and for suggesting the +addition of the Ground Distance value in the Descent tab.
AltOS fixes:
AltosUI new features:
AltosUI fixes:
Version 1.1 is a minor release. It provides a few new features +in AltosUI and the AltOS firmware and fixes bugs.
AltOS Firmware New Features:
AltOS Fixes:
AltosUI New Features:
AltosUI Fixes:
Version 1.0.1 is a major release, adding support for the +TeleMini device and lots of new AltosUI features
AltOS New Features
AltOS Fixes
AltosUI New Features
AltosUI Changes
Version 0.9.2 is an AltosUI bug-fix release, with no firmware +changes.
Version 0.9 adds a few new firmware features and accompanying +AltosUI changes, along with new hardware support.
Version 0.8 offers a major upgrade in the AltosUI +interface.
Version 0.7.1 is the first release containing our new +cross-platform Java-based user interface.