X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=blobdiff_plain;f=doc%2Faltusmetrum.xsl;h=fb08f5c642fa32f284ba2958a14d76a77b762794;hp=dfd72ab46f99f8fd425ece356f0fe149b01771b5;hb=debian;hpb=013cba5ed1fde72240a68ec648bd14977f5e48a4 diff --git a/doc/altusmetrum.xsl b/doc/altusmetrum.xsl deleted file mode 100644 index dfd72ab4..00000000 --- a/doc/altusmetrum.xsl +++ /dev/null @@ -1,2876 +0,0 @@ - - - - The Altus Metrum System - An Owner's Manual for TeleMetrum, TeleMini, TeleDongle and TeleBT Devices - - - Bdale - Garbee - - - Keith - Packard - - - Bob - Finch - - - Anthony - Towns - - - 2013 - Bdale Garbee and Keith Packard - - - - This document is released under the terms of the - - Creative Commons ShareAlike 3.0 - - license. - - - - - 1.2.1 - 21 May 2013 - - Updated for software version 1.2. Version 1.2 adds support - for TeleBT and AltosDroid. It also adds a few minor features - and fixes bugs in AltosUI and the AltOS firmware. - - - - 1.2 - 18 April 2013 - - Updated for software version 1.2. Version 1.2 adds support - for MicroPeak and the MicroPeak USB interface. - - - - 1.1.1 - 16 September 2012 - - Updated for software version 1.1.1 Version 1.1.1 fixes a few - bugs found in version 1.1. - - - - 1.1 - 13 September 2012 - - Updated for software version 1.1. Version 1.1 has new - features but is otherwise compatible with version 1.0. - - - - 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. - - - - 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. - - - - 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 - - - - - Introduction and Overview - - 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. - - - Our second device was 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. - - - TeleDongle 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. - - - 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 Altos Droid - 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. - - - - Getting Started - - 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 - such as the LipoCharger product included in TeleMini Starter Kits, - 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 - . - - - If you're using a TeleBT instead of the TeleDongle, you'll want - to go install the Altos Droid application from the Google Play - store. You don't need a data plan to use Altos Droid, but - without network access, the Map view will be less useful as it - won't contain any map data. You can also use TeleBT connected - over USB with your laptop computer; it acts exactly like a - TeleDongle. Anywhere this manual talks about TeleDongle, you can - also read that as 'and TeleBT when connected via USB'. - - - - Handling Precautions - - 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. - - - - Hardware Overview - - 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. - - - The battery connectors are a standard 2-pin JST connector and - match batteries sold by Spark Fun. 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 or Spark Fun. - - - 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. - - - - System Operation -
- Firmware Modes - - 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! - - - TeleMini is configured via the radio link. Of course, that - means you need to know the TeleMini radio configuration values - or you won't be able to communicate with it. For situations - when you don't have the radio configuration values, TeleMini - offers an 'emergency recovery' mode. In this mode, TeleMini is - configured as follows: - - - Sets the radio frequency to 434.550MHz - - - Sets the radio calibration back to the factory value. - - - Sets the callsign to N0CALL - - - Does not go to 'pad' mode after five seconds. - - - - - 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 it's in - 'idle' mode after the initial five second startup period. - -
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- GPS - - 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. - -
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- Controlling An Altimeter Over The Radio Link - - 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 transmitted, while the green LED will light up on TeleDongle when - it is waiting to receive a packet from the altimeter. - -
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- Ground Testing - - 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. - -
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- Radio Link - - 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! - -
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- Configurable Parameters - - 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. - -
- Radio Frequency - - 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. - -
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- Apogee Delay - - 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. - -
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- Main Deployment Altitude - - 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. - -
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- Maximum Flight Log - - 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. - -
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- Ignite Mode - - 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. - -
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- Pad Orientation - - 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. - -
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- - - - - AltosUI - - 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. - -
- Monitor Flight - Receive, Record and Display Telemetry Data - - 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. - - - - - The age of the displayed data, in seconds since the last - successfully received telemetry packet. In normal operation - this will stay in the low single digits. If the number starts - counting up, then you are no longer receiving data over the radio - link from the flight computer. - - - - - 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. - -
- Launch Pad - - 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. - - -
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- Ascent - - 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. - -
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- Descent - - 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. 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. - -
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- Landed - - 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. - -
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- Site Map - - 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. - -
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- Save Flight Data - - 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. - -
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- Replay Flight - - 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. - -
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- Graph Data - - 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 four 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 lets you configure which data to show in the graph. The - third contains some basic flight statistics while the fourth - has a map with the ground track of the flight displayed. - - - 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. - -
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- Export Data - - 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. - -
- Comma Separated Value Format - - 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. - -
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- Keyhole Markup Language (for Google Earth) - - This is the format used by Google Earth to provide an overlay - within that application. With this, you can use Google Earth to - see the whole flight path in 3D. - -
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- Configure Altimeter - - 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. - -
- Main Deploy Altitude - - 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. - -
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- Apogee Delay - - 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. - -
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- Radio Frequency - - 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. - -
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- Radio Calibration - - 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. - -
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- Callsign - - This sets the call sign included in each telemetry packet. Set this - as needed to conform to your local radio regulations. - -
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- Maximum Flight Log Size - - 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. - -
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- Ignite Mode - - 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. - - - -
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- Pad Orientation - - 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. - - - -
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- Configure AltosUI - - This button presents a dialog so that you can configure the AltosUI global settings. - -
- Voice 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 - - - -
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- Log Directory - - 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. - -
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- Callsign - - 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. - -
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- Imperial Units - - 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. - -
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- Font Size - - Selects the set of fonts used in the flight monitor - window. Choose between the small, medium and large sets. - -
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- Serial Debug - - 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. - -
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- Manage Frequencies - - 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. - -
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- Configure Groundstation - - 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. - -
- Frequency - - 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. - -
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- Radio Calibration - - 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. - -
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- Flash Image - - 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. - -
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- Fire Igniter - - 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. - -
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- Scan Channels - - 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. - -
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- Load Maps - - 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. - -
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- Monitor Idle - - This brings up a dialog similar to the Monitor Flight UI, - except it works with the altimeter in "idle" mode by sending - query commands to discover the current state rather than - listening for telemetry packets. - -
- - - AltosDroid - - AltosDroid provides the same flight monitoring capabilities as - AltosUI, but runs on Android devices and is designed to connect - to a TeleBT receiver over Bluetooth™. Altos Droid monitors - telemetry data, logging it to internal storage in the Android - device, and presents that data in a UI the same way the 'Monitor - Flight' window does in AltosUI. - - - This manual will explain how to configure AltosDroid, connect - to TeleBT, operate the flight monitoring interface and describe - what the displayed data means. - -
- Installing AltosDroid - - AltosDroid is included in the Google Play store. To install - it on your Android device, open open the Google Play Store - application and search for "altosdroid". Make sure you don't - have a space between "altos" and "droid" or you probably won't - find what you want. That should bring you to the right page - from which you can download and install the application. - -
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- Connecting to TeleBT - - 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. - -
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- Configuring AltosDroid - - The only configuration option available for AltosDroid is - which frequency to listen on. Press the Android 'Menu' button - or soft-key and pick the 'Select radio frequency' entry. That - brings up a menu of pre-set radio frequencies; pick the one - which matches your altimeter. - -
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- Altos Droid Flight Monitoring - - Altos Droid 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. - -
- Pad - - 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. - - -
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- Downloading Flight Logs - - Altos Droid always saves every bit of telemetry data it - receives. To download that to a computer for use with AltosUI, - simply remove the SD card from your Android device, or connect - your device to your computer's USB port and browse the files - on that device. You will find '.telem' files in the TeleMetrum - directory that will work with AltosUI directly. - -
- - - Using Altus Metrum Products -
- Being Legal - - 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. - -
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- In the Rocket - - 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. - -
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- On the Ground - - 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. 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: - - - an antenna and feed-line or adapter - - - a TeleDongle - - - a notebook computer - - - optionally, a hand-held GPS receiver - - - optionally, an HT or receiver covering 435 MHz - - - - - 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. TeleDongle and an SMA to BNC adapter fit perfectly - between the driven element and reflector of Arrow antennas. - -
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- Data Analysis - - 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. - -
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- Future Plans - - 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. - - - Also under design is a new flight computer with more sensors, more - pyro channels, and a more powerful radio system designed for use - in multi-stage, complex, and extreme altitude projects. - - - We are also working on alternatives to TeleDongle. One is a - a stand-alone, 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. We are also working on a TeleDongle variant with - Bluetooth that will work with Android phones and tablets. - - - 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... - - - Watch our - web site for more news - and information as our family of products evolves! - -
- - - Altimeter Installation Recommendations - - 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. - -
- Mounting the Altimeter - - 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. - - - - Make sure TeleMetrum is aligned precisely along the axis of - acceleration so that the accelerometer can accurately - capture data during the flight. - - - Watch for any metal touching components on the - board. Shorting out connections on the bottom of the board - can cause the altimeter to fail during flight. - - -
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- Dealing with the Antenna - - 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. - -
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- Preserving GPS Reception - - 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. - - - Conductive tubing or coatings. Carbon fiber and metal - tubing, or metallic paint will all dramatically attenuate the - GPS signal. We've never heard of anyone successfully - receiving GPS from inside these materials. - - - Metal components near the GPS patch antenna. These will - de-tune the patch antenna, changing the resonant frequency - away from the L1 carrier and reduce the effectiveness of the - antenna. You can place as much stuff as you like beneath the - antenna as that's covered with a ground plane. But, keep - wires and metal out from above the patch antenna. - - - -
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- Radio Frequency Interference - - 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: - - - - Keep wires from different circuits apart. Moving circuits - further apart will reduce RFI. - - - Avoid parallel wires from different circuits. The longer two - wires run parallel to one another, the larger the amount of - transferred energy. Cross wires at right angles to reduce - RFI. - - - Twist wires from the same circuits. Two wires the same - distance from the transmitter will get the same amount of - induced energy which will then cancel out. Any time you have - a wire pair running together, twist the pair together to - even out distances and reduce RFI. For altimeters, this - includes battery leads, switch hookups and igniter - circuits. - - - Avoid resonant lengths. Know what frequencies are present - in the environment and avoid having wire lengths near a - natural resonant length. Altusmetrum products transmit on the - 70cm amateur band, so you should avoid lengths that are a - simple ratio of that length; essentially any multiple of 1/4 - of the wavelength (17.5cm). - - -
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- The Barometric Sensor - - 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. - -
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- Ground Testing - - 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. - -
- - - Updating Device Firmware - - 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 . - - - We recommend updating the altimeter first, before updating TeleDongle. - -
- Updating TeleMetrum Firmware - - - Find the 'programming cable' that you got as part of the starter - kit, that has a red 8-pin MicroMaTch connector on one end and a - red 4-pin MicroMaTch connector on the other end. - - - Take the 2 screws out of the TeleDongle case to get access - to the circuit board. - - - Plug the 8-pin end of the programming cable to the - matching connector on the TeleDongle, and the 4-pin end to the - matching connector on the TeleMetrum. - Note that each MicroMaTch connector has an alignment pin that - goes through a hole in the PC board when you have the cable - oriented correctly. - - - Attach a battery to the TeleMetrum board. - - - Plug the TeleDongle into your computer's USB port, and power - up the TeleMetrum. - - - Run AltosUI, and select 'Flash Image' from the File menu. - - - Pick the TeleDongle device from the list, identifying it as the - programming device. - - - Select the image you want put on the TeleMetrum, which should have a - name in the form telemetrum-v1.2-1.0.0.ihx. It should be visible - in the default directory, if not you may have to poke around - your system to find it. - - - Make sure the configuration parameters are reasonable - looking. If the serial number and/or RF configuration - values aren't right, you'll need to change them. - - - Hit the 'OK' button and the software should proceed to flash - the TeleMetrum with new firmware, showing a progress bar. - - - Confirm that the TeleMetrum board seems to have updated OK, which you - can do by plugging in to it over USB and using a terminal program - to connect to the board and issue the 'v' command to check - the version, etc. - - - If something goes wrong, give it another try. - - -
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- Updating TeleMini Firmware - - - You'll need a special 'programming cable' to reprogram the - TeleMini. It's available on the Altus Metrum web store, or - you can make your own using an 8-pin MicroMaTch connector on - one end and a set of four pins on the other. - - - Take the 2 screws out of the TeleDongle case to get access - to the circuit board. - - - Plug the 8-pin end of the programming cable to the matching - connector on the TeleDongle, and the 4-pins into the holes - in the TeleMini circuit board. Note that the MicroMaTch - connector has an alignment pin that goes through a hole in - the PC board when you have the cable oriented correctly, and - that pin 1 on the TeleMini board is marked with a square pad - while the other pins have round pads. - - - Attach a battery to the TeleMini board. - - - Plug the TeleDongle into your computer's USB port, and power - up the TeleMini - - - Run AltosUI, and select 'Flash Image' from the File menu. - - - Pick the TeleDongle device from the list, identifying it as the - programming device. - - - Select the image you want put on the TeleMini, which should have a - name in the form telemini-v1.0-1.0.0.ihx. It should be visible - in the default directory, if not you may have to poke around - your system to find it. - - - Make sure the configuration parameters are reasonable - looking. If the serial number and/or RF configuration - values aren't right, you'll need to change them. - - - Hit the 'OK' button and the software should proceed to flash - the TeleMini with new firmware, showing a progress bar. - - - Confirm that the TeleMini board seems to have updated OK, which you - can do by configuring it over the radio link through the TeleDongle, or - letting it come up in "flight" mode and listening for telemetry. - - - If something goes wrong, give it another try. - - -
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- Updating TeleDongle Firmware - - Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini - firmware, but you use either a TeleMetrum or another TeleDongle as the programmer. - - - - Find the 'programming cable' that you got as part of the starter - kit, that has a red 8-pin MicroMaTch connector on one end and a - red 4-pin MicroMaTch connector on the other end. - - - Find the USB cable that you got as part of the starter kit, and - plug the "mini" end in to the mating connector on TeleMetrum or TeleDongle. - - - Take the 2 screws out of the TeleDongle case to get access - to the circuit board. - - - Plug the 8-pin end of the programming cable to the - matching connector on the programmer, and the 4-pin end to the - matching connector on the TeleDongle. - Note that each MicroMaTch connector has an alignment pin that - goes through a hole in the PC board when you have the cable - oriented correctly. - - - Attach a battery to the TeleMetrum board if you're using one. - - - Plug both the programmer and the TeleDongle into your computer's USB - ports, and power up the programmer. - - - Run AltosUI, and select 'Flash Image' from the File menu. - - - Pick the programmer device from the list, identifying it as the - programming device. - - - Select the image you want put on the TeleDongle, which should have a - name in the form teledongle-v0.2-1.0.0.ihx. It should be visible - in the default directory, if not you may have to poke around - your system to find it. - - - Make sure the configuration parameters are reasonable - looking. If the serial number and/or RF configuration - values aren't right, you'll need to change them. The TeleDongle - serial number is on the "bottom" of the circuit board, and can - usually be read through the translucent blue plastic case without - needing to remove the board from the case. - - - Hit the 'OK' button and the software should proceed to flash - the TeleDongle with new firmware, showing a progress bar. - - - Confirm that the TeleDongle board seems to have updated OK, which you - can do by plugging in to it over USB and using a terminal program - to connect to the board and issue the 'v' command to check - the version, etc. Once you're happy, remove the programming cable - and put the cover back on the TeleDongle. - - - If something goes wrong, give it another try. - - - - 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. - -
- - - Hardware Specifications -
- TeleMetrum Specifications - - - - 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. - - - -
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- TeleMini Specifications - - - - 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 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. - - - -
- - - FAQ - - 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... - - - - Notes for Older Software - - - 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! - - - - Drill Templates - - These images, when printed, provide precise templates for the - mounting holes in Altus Metrum flight computers - -
- TeleMetrum template - - TeleMetrum has overall dimensions of 1.000 x 2.750 inches, and the - mounting holes are sized for use with 4-40 or M3 screws. - - - - - - -
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- TeleMini template - - TeleMini has overall dimensions of 0.500 x 1.500 inches, and the - mounting holes are sized for use with 2-56 or M2 screws. - - - - - - -
- - - Calibration - - 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. - -
- Radio Frequency - - 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. - -
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- TeleMetrum Accelerometer - - 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. - -
- - - Release Notes - Version 1.21 - Version 1.2 - Version 1.1.1 - Version 1.1 - Version 1.0.1 - Version 0.9.2 - Version 0.9 - Version 0.8 - Version 0.7.1 - - - -