Copyright © 2017 Bdale Garbee and Keith Packard
This document is released under the terms of the Creative Commons ShareAlike 3.0 license.
Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing “The Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter Kit” which formed the basis of the original Getting Started chapter in this manual. Bob was one of our first customers for a production TeleMetrum, and his continued enthusiasm and contributions are immensely gratifying and highly appreciated!
And thanks to Anthony (AJ) Towns for major contributions including the AltosUI graphing and site map code and associated documentation. Free software means that our customers and friends can become our collaborators, and we certainly appreciate this level of contribution!
Have fun using these products, and we hope to meet all of you out on the rocket flight line somewhere.
Bdale Garbee, KB0G
NAR #87103, TRA #12201
Keith Packard, KD7SQG
NAR #88757, TRA #12200
Table of Contents
List of Figures
List of Tables
Welcome to the Altus Metrum community! Our circuits and software reflect our passion for both hobby rocketry and Free Software. We hope their capabilities and performance will delight you in every way, but by releasing all of our hardware and software designs under open licenses, we also hope to empower you to take as active a role in our collective future as you wish!
The first device created for our community was TeleMetrum, a dual deploy altimeter with fully integrated GPS and radio telemetry as standard features, and a “companion interface” that will support optional capabilities in the future. The latest version of TeleMetrum, v2.0, has all of the same features but with improved sensors and radio to offer increased performance.
Our second device was TeleMini, a dual deploy altimeter with radio telemetry and radio direction finding. The first version of this device was only 13mm by 38mm (½ inch by 1½ inches) and could fit easily in an 18mm air-frame. The latest version, v3.0, includes a beeper, higher power radio, extended on-board flight logging and an improved barometric sensor.
TeleMega is our most sophisticated device, including six pyro channels (four of which are fully programmable), integrated GPS, integrated gyroscopes for staging/air-start inhibit and high performance telemetry.
EasyMini is a dual-deploy altimeter with logging and built-in USB data download.
EasyMega is essentially a TeleMega board with the GPS receiver and telemetry transmitter removed. It offers the same 6 pyro channels and integrated gyroscopes for staging/air-start inhibit.
TeleDongle v0.2 was our first ground station, providing a USB to RF interfaces for communicating with the altimeters. Combined with your choice of antenna and notebook computer, TeleDongle and our associated user interface software form a complete ground station capable of logging and displaying in-flight telemetry, aiding rocket recovery, then processing and archiving flight data for analysis and review. The latest version, TeleDongle v3, has all new electronics with a higher performance radio for improved range.
For a slightly more portable ground station experience that also provides direct rocket recovery support, TeleBT offers flight monitoring and data logging using a Bluetooth™ connection between the receiver and an Android device that has the AltosDroid application installed from the Google Play store.
More products will be added to the Altus Metrum family over time, and we currently envision that this will be a single, comprehensive manual for the entire product family.
The first thing to do after you open the box is to hook up a battery and charge it if necessary.
For TeleMetrum, TeleMega and EasyMega, the battery can be charged by plugging it into the corresponding socket of the device and then using the USB cable to plug the flight computer into your computer’s USB socket. The on-board circuitry will charge the battery whenever it is plugged in, because the on-off switch does NOT control the charging circuitry. The Lithium Polymer TeleMini and EasyMini battery can be charged by disconnecting it from the board and plugging it into a standalone battery charger such as LipoCharger, and connecting that via a USB cable to a laptop or other USB power source.
You can also choose to use another battery with EasyMini, anything supplying between 4 and 12 volts should work fine (like a standard 9V battery), but if you are planning to fire pyro charges, ground testing is required to verify that the battery supplies enough current to fire your chosen e-matches.
On TeleMetrum v1 boards, when the GPS chip is initially searching for satellites, TeleMetrum will consume more current than it pulls from the USB port, so the battery must be attached in order to get satellite lock. Once GPS is locked, the current consumption goes back down enough to enable charging while running. So 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.
TeleMetrum v2.0, TeleMega and EasyMega use a higher power battery charger, allowing them to charge the battery while running the board at maximum power. When the battery is charging, or when the board is consuming a lot of power, the red LED will be lit. When the battery is fully charged, the green LED will be lit. When the battery is damaged or missing, both LEDs will be lit, which appears yellow.
There are two ground stations available, the TeleDongle USB to RF interface and the TeleBT Bluetooth/USB to RF interface. If you plug either of these in to your Mac or Linux computer it should “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 an older version of Linux and are having problems, try moving to a fresher kernel (2.6.33 or newer).
Next you should obtain and install the AltOS software. The AltOS distribution includes the AltosUI ground station program, current firmware images for all of the hardware, and a number of standalone utilities that are rarely needed. Pre-built binary packages are available for Linux, Microsoft Windows, Mac OSX. Full source code and build instructions are also available. The latest version may always be downloaded from http://altusmetrum.org/AltOS
TeleBT can also connect to an Android device over BlueTooth or USB. The AltosDroid Android application is available from the Google Play system.
You don’t need a data plan to use AltosDroid, but without network access, you’ll want to download offline map data before wandering away from the network.
Here are general instructions for hooking up an Altus Metrum flight computer. Instructions specific to each model will be found in the section devoted to that model below.
To prevent electrical interference from affecting the operation of the flight computer, it’s important to always twist pairs of wires connected to the board. Twist the switch leads, the pyro leads and the battery leads. This reduces interference through a mechanism called common mode rejection.
All Altus Metrum flight computers have a two pin JST PH series connector to connect up a single-cell Lithium Polymer cell (3.7V nominal). You can purchase matching batteries from the Altus Metrum store, or other vendors, or you can make your own. Pin 1 of the connector is positive, pin 2 is negative. Spark Fun sells a cable with the connector attached, which they call a JST Jumper 2 Wire Assembly
Many RC vendors also sell lithium polymer batteries with this same connector. All that we have found use the opposite polarity, and if you use them that way, you will damage or destroy the flight computer.
Altus Metrum flight computers always have two screws for each pyro charge. This means you shouldn’t need to put two wires into a screw terminal or connect leads from pyro charges together externally.
On the flight computer, one lead from each charge is hooked to the positive battery terminal through the power switch. The other lead is connected through the pyro circuit, which is connected to the negative battery terminal when the pyro circuit is fired.
Altus Metrum flight computers need an external power switch to turn them on. This disconnects both the computer and the pyro charges from the battery, preventing the charges from firing when in the Off position. The switch is in-line with the positive battery terminal.
Altus Metrum flight computers include a beeper to provide information about the state of the system. TeleMini doesn’t have room for a beeper, so instead it uses an LED, which works the same, except for every beep is replaced with the flash of the LED.
Here’s a short summary of all of the modes and the beeping (or flashing, in the case of TeleMini v1) that accompanies each mode. In the description of the beeping pattern, “dit” means a short beep while "dah" means a long beep (three times as long). “Brap” means a long dissonant tone.
Table 3.1. AltOS Modes
Mode Name | Abbreviation | Beeps | Description |
Startup | S | battery voltage in decivolts | Calibrating sensors, detecting orientation. |
Idle | I | dit dit | Ready to accept commands over USB or radio link. |
Pad | P | dit dah dah dit | Waiting for launch. Not listening for commands. |
Boost | B | dah dit dit dit | Accelerating upwards. |
Fast | F | dit dit dah dit | Decelerating, but moving faster than 200m/s. |
Coast | C | dah dit dah dit | Decelerating, moving slower than 200m/s |
Drogue | D | dah dit dit | Descending after apogee. Above main height. |
Main | M | dah dah | Descending. Below main height. |
Landed | L | dit dah dit dit | Stable altitude for at least ten seconds. |
Sensor error | X | dah dit dit dah | Error detected during sensor calibration. |
Here’s a summary of all of the Pad and Idle mode indications. In Idle mode, you’ll hear one of these just once after the two short dits indicating idle mode. In Pad mode, after the dit dah dah dit indicating Pad mode, you’ll hear these once every five seconds.
Table 3.2. Pad/Idle Indications
Name | Beeps | Description |
---|---|---|
Neither | brap | No continuity detected on either apogee or main igniters. |
Apogee | dit | Continuity detected only on apogee igniter. |
Main | dit dit | Continuity detected only on main igniter. |
Both | dit dit dit | Continuity detected on both igniters. |
Storage Full | warble | On-board data logging storage is full. This will not prevent the flight computer from safely controlling the flight or transmitting telemetry signals, but no record of the flight will be stored in on-board flash. |
Additional Igniters | four very short beeps | Continuity indication for the four additional pyro channels on TeleMega and EasyMega. One high tone for no continuity, one low tone for continuity. These are produced after the continuity indicators for the two primary igniter channels. |
For devices with a radio transmitter, in addition to the digital and APRS telemetry signals, you can also receive audio tones with a standard amateur 70cm FM receiver. While on the pad, you will hear igniter status once every five seconds.
Table 3.3. Pad Radio Indications
Name | Beeps | Description |
---|---|---|
Neither | ½ second tone | No continuity detected on either apogee or main igniters. |
Apogee | dit | Continuity detected only on apogee igniter. |
Main | dit dit | Continuity detected only on main igniter. |
Both | dit dit dit | Continuity detected on both igniters. |
During ascent, the tones will be muted to allow the telemetry data to consume the full radio bandwidth.
During descent and after landing, a ½ second tone will be transmitted every five seconds. This can be used to find the rocket using RDF techniques when the signal is too weak to receive GPS information via telemetry or APRS.
Connect a battery and power switch and turn the switch to "on". The flight computer will signal power on by reporting the battery voltage and then perform an internal self test and sensor calibration.
Once the self test and calibration are complete, there are two modes that an Altus Metrum flight computer can operate in:
For flight computers with accelerometers (TeleMetrum, EasyMega and TeleMega), the mode is selected by the orientation of the board during the self test interval. If the board is pointing upwards as if ready to fly, it will enter Flight/Pad mode. Otherwise, it will enter Idle mode.
For EasyMini, if the USB cable is connected to a computer, it will enter Idle mode. Otherwise, it will enter Flight/Pad mode.
For TeleMini v1.0, if a packet link is waiting to connect when the device is powered on, it will enter Idle mode, otherwise it will enter Flight/Pad mode.
You can see in Section 3.5, “Understanding Beeps” how to tell which mode the flight computer is in.
You can use an active switch circuit, such as the Featherweight Magnetic Switch, with any Altus Metrum flight computer. These require three connections, one to the battery, one to the positive power input on the flight computer and one to ground. Find instructions on how to hook these up for each flight computer below. Then follow the instructions that come with your active switch to connect it up.
As mentioned above in Section 3.3, “Hooking Up Pyro Charges”, one lead for each of the pyro charges is connected through the power switch directly to the positive battery terminal. The other lead is connected to the pyro circuit, which connects it to the negative battery terminal when the pyro circuit is fired. The pyro circuit on all of the flight computers is designed to handle up to 16V.
To use a separate pyro battery, connect the negative pyro battery terminal to the flight computer ground terminal, the positive battery terminal to the igniter and the other igniter lead to the negative pyro terminal on the flight computer. When the pyro channel fires, it will complete the circuit between the negative pyro terminal and the ground terminal, firing the igniter. Specific instructions on how to hook this up for each flight computer will be found in the section below for that flight computer.
EasyMini and TeleMini v2 are designed to use either a lithium polymer battery or any other battery producing between 4 and 12 volts, such as a rectangular 9V battery.
TeleMega, EasyMega and TeleMetrum are only designed to operate off a single-cell Lithium Polymer battery and cannot be used with any other kind. Connecting a different kind of battery to any of these will destroy the board.
TeleMetrum is a 1 inch by 2¾ inch circuit board. It was designed to fit inside coupler for 29mm air-frame tubing, but using it in a tube that small in diameter may require some creativity in mounting and wiring to succeed! The presence of an accelerometer means TeleMetrum should be aligned along the flight axis of the airframe, and by default the ¼ wave UHF wire antenna should be on the nose-cone end of the board. The antenna wire is about 7 inches long, and wiring for a power switch and the e-matches for apogee and main ejection charges depart from the fin can end of the board, meaning an ideal “simple” avionics bay for TeleMetrum should have at least 10 inches of interior length.
There are two generations of the TeleMetrum design. The major changes in the v2 generation are:
Otherwise, they’re the same size, with mounting holes and screw terminals in the same position.
TeleMetrum has six screw terminals on the end of the board opposite the telemetry antenna. Two are for the power switch, and two each for the apogee and main igniter circuits. Using the picture above and starting from the top, the terminals are as follows:
Table 4.1. TeleMetrum Screw Terminals
Terminal # | Terminal Name | Description |
---|---|---|
1 | Switch Output | Switch connection to flight computer |
2 | Switch Input | Switch connection to positive battery terminal |
3 | Main + | Main pyro channel common connection to battery |
4 | Main - | Main pyro channel connection to pyro circuit |
5 | Apogee + | Apogee pyro channel common connection to battery |
6 | Apogee - | Apogee pyro channel connection to pyro circuit |
As described above, using an external pyro battery involves connecting the negative battery terminal to the flight computer ground, connecting the positive battery terminal to one of the igniter leads and connecting the other igniter lead to the per-channel pyro circuit connection.
To connect the negative battery terminal to the TeleMetrum ground, insert a small piece of wire, 24 to 28 gauge stranded, into the GND hole just above the screw terminal strip and solder it in place.
Connecting the positive battery terminal to the pyro charges must be done separate from TeleMetrum, by soldering them together or using some other connector.
The other lead from each pyro charge is then inserted into the appropriate per-pyro channel screw terminal (terminal 4 for the Main charge, terminal 6 for the Apogee charge).
As explained above, an external active switch requires three connections, one to the positive battery terminal, one to the flight computer positive input and one to ground.
The positive battery terminal is available on screw terminal 2, the positive flight computer input is on terminal 1. To hook a lead to ground, solder a piece of wire, 24 to 28 gauge stranded, to the GND hole just above terminal 1.
TeleMini v3 is 0.5 inches by 1.67 inches. It was designed to fit inside an 18mm air-frame tube, but using it in a tube that small in diameter may require some creativity in mounting and wiring to succeed! Since there is no accelerometer, TeleMini can be mounted in any convenient orientation. The default ¼ wave UHF wire antenna attached to the center of one end of the board is about 7 inches long. Screw terminals for the power switch are located in the middle of the board. Screw terminals for the e-matches for apogee and main ejection charges depart from the other end of the board, meaning an ideal “simple” avionics bay for TeleMini should have at least 9 inches of interior length.
TeleMini v3 has four screw terminals on the end of the board opposite the telemetry antenna. Two are for the apogee and two are for main igniter circuits. Another two screw terminals are located in the middle of the board for the power switch. Using the picture above and starting from the top for the pyro terminals and from the left for the power switch terminals, the connections are as follows:
Table 5.1. TeleMini v3 Screw Terminals
Terminal # | Terminal Name | Description |
---|---|---|
1 | Apogee - | Apogee pyro channel connection to pyro circuit |
2 | Apogee | Apogee pyro channel common connection to battery |
3 | Main - | Main pyro channel connection to pyro circuit |
4 | Main | Main pyro channel common connection to battery |
Left | Switch Output | Switch connection to flight computer |
Right | Switch Input | Switch connection to positive battery terminal |
As described above, using an external pyro battery involves connecting the negative battery terminal to the flight computer ground, connecting the positive battery terminal to one of the igniter leads and connecting the other igniter lead to the per-channel pyro circuit connection. Because there is no solid ground connection to use on TeleMini, this is not recommended.
The only available ground connection on TeleMini v3 are the two mounting holes next to the telemetry antenna. Somehow connect a small piece of wire to one of those holes and hook it to the negative pyro battery terminal.
Connecting the positive battery terminal to the pyro charges must be done separate from TeleMini v3, by soldering them together or using some other connector.
The other lead from each pyro charge is then inserted into the appropriate per-pyro channel screw terminal (terminal 3 for the Main charge, terminal 1 for the Apogee charge).
As explained above, an external active switch requires three connections, one to the positive battery terminal, one to the flight computer positive input and one to ground. Again, because TeleMini doesn’t have any good ground connection, this is not recommended.
The positive battery terminal is available on the Right power switch wire, the positive flight computer input is on the left power switch wire. Hook a lead to either of the mounting holes for a ground connection.
EasyMini is built on a 0.8 inch by 1½ inch circuit board. It’s designed to fit in a 24mm coupler tube.
You usually don’t need to configure EasyMini at all; it’s set up to do dual-deployment with an event at apogee to separate the airframe and deploy a drogue and another event at 250m (820ft) to deploy the main. Install EasyMini in your airframe, hook up a battery, igniters and a power switch and you’re ready to fly.
EasyMini has two sets of four screw terminals near one end of the board. Using the picture above, the top four have connections for the main pyro circuit and an external battery and the bottom four have connections for the apogee pyro circuit and the power switch. Counting from the left, the connections are as follows:
Table 6.1. EasyMini Screw Terminals
Terminal # | Terminal Name | Description |
---|---|---|
Top 1 | Main - | Main pyro channel connection to pyro circuit |
Top 2 | Main | Main pyro channel common connection to battery |
Top 3 | Battery | Positive external battery terminal |
Top 4 | Battery - | Negative external battery terminal |
Bottom 1 | Apogee - | Apogee pyro channel connection to pyro circuit |
Bottom 2 | Apogee | Apogee pyro channel common connection to battery |
Bottom 3 | Switch Output | Switch connection to flight computer |
Bottom 4 | Switch Input | Switch connection to positive battery terminal |
There are two possible battery connections on EasyMini. You can use either method; both feed through the power switch terminals.
One battery connection is the standard Altus Metrum white JST plug. This mates with single-cell Lithium Polymer batteries sold by Altus Metrum.
The other is a pair of screw terminals marked Battery + and Battery -. Connect a battery from 4 to 12 volts to these terminals, being careful to match polarity.
Because EasyMini allows for batteries other than the standard Altus Metrum Lithium Polymer cells, it cannot incorporate a battery charger circuit. Therefore, when using a Litium Polymer cell, you’ll need an external charger. These are available from Altus Metrum, or from Spark Fun.
As described above, using an external pyro battery involves connecting the negative battery terminal to the flight computer ground, connecting the positive battery terminal to one of the igniter leads and connecting the other igniter lead to the per-channel pyro circuit connection.
To connect the negative pyro battery terminal to EasyMini ground, connect it to the negative external battery connection, top terminal 4.
Connecting the positive battery terminal to the pyro charges must be done separate from EasyMini, by soldering them together or using some other connector.
The other lead from each pyro charge is then inserted into the appropriate per-pyro channel screw terminal (top terminal 1 for the Main charge, bottom terminal 1 for the Apogee charge).
As explained above, an external active switch requires three connections, one to the positive battery terminal, one to the flight computer positive input and one to ground. Use the negative external battery connection, top terminal 4 for ground.
The positive battery terminal is available on bottom terminal 4, the positive flight computer input is on the bottom terminal 3.
TeleMega is a 1¼ inch by 3¼ inch circuit board. It was designed to easily fit in a 38mm coupler. Like TeleMetrum, TeleMega has an accelerometer and so it must be mounted so that the board is aligned with the flight axis. It can be mounted either antenna up or down.
TeleMega v2.0 has a few minor changes from v1.0:
None of these affect operation using the stock firmware, but they do mean that the device needs different firmware to operate correctly, so make sure you load the right firmware when reflashing the device.
TeleMega has two sets of nine screw terminals on the end of the board opposite the telemetry antenna. They are as follows:
Table 7.1. TeleMega Screw Terminals
Terminal # | Terminal Name | Description |
---|---|---|
Top 1 | Switch Input | Switch connection to positive battery terminal |
Top 2 | Switch Output | Switch connection to flight computer |
Top 3 | GND | Ground connection for use with external active switch |
Top 4 | Main - | Main pyro channel connection to pyro circuit |
Top 5 | Main | Main pyro channel common connection to battery |
Top 6 | Apogee - | Apogee pyro channel connection to pyro circuit |
Top 7 | Apogee | Apogee pyro channel common connection to battery |
Top 8 | D - | D pyro channel connection to pyro circuit |
Top 9 | D | D pyro channel common connection to battery |
Bottom 1 | GND | Ground connection for negative pyro battery terminal |
Bottom 2 | Pyro | Positive pyro battery terminal |
Bottom 3 | Lipo | Power switch output. Use to connect main battery to pyro battery input |
Bottom 4 | A - | A pyro channel connection to pyro circuit |
Bottom 5 | A | A pyro channel common connection to battery |
Bottom 6 | B - | B pyro channel connection to pyro circuit |
Bottom 7 | B | B pyro channel common connection to battery |
Bottom 8 | C - | C pyro channel connection to pyro circuit |
Bottom 9 | C | C pyro channel common connection to battery |
TeleMega provides explicit support for an external pyro battery. All that is required is to remove the jumper between the lipo terminal (Bottom 3) and the pyro terminal (Bottom 2). Then hook the negative pyro battery terminal to ground (Bottom 1) and the positive pyro battery to the pyro battery input (Bottom 2). You can then use the existing pyro screw terminals to hook up all of the pyro charges.
Because TeleMega has built-in support for a separate pyro battery, if you want to fly with just one battery running both the computer and firing the charges, you need to connect the flight computer battery to the pyro circuit. TeleMega has two screw terminals for this—hook a wire from the Lipo terminal (Bottom 3) to the Pyro terminal (Bottom 2).
As explained above, an external active switch requires three connections, one to the positive battery terminal, one to the flight computer positive input and one to ground.
The positive battery terminal is available on Top terminal 1, the positive flight computer input is on Top terminal 2. Ground is on Top terminal 3.
EasyMega is a 1¼ inch by 2¼ inch circuit board. It was designed to easily fit in a 38mm coupler. Like TeleMetrum, EasyMega has an accelerometer and so it must be mounted so that the board is aligned with the flight axis. It can be mounted either antenna up or down.
EasyMega has two sets of nine screw terminals on the end of the board opposite the telemetry antenna. They are as follows:
Table 8.1. EasyMega Screw Terminals
Terminal # | Terminal Name | Description |
---|---|---|
Top 1 | Switch Input | Switch connection to positive battery terminal |
Top 2 | Switch Output | Switch connection to flight computer |
Top 3 | GND | Ground connection for use with external active switch |
Top 4 | Main - | Main pyro channel connection to pyro circuit |
Top 5 | Main | Main pyro channel common connection to battery |
Top 6 | Apogee - | Apogee pyro channel connection to pyro circuit |
Top 7 | Apogee | Apogee pyro channel common connection to battery |
Top 8 | D - | D pyro channel connection to pyro circuit |
Top 9 | D | D pyro channel common connection to battery |
Bottom 1 | GND | Ground connection for negative pyro battery terminal |
Bottom 2 | Pyro | Positive pyro battery terminal |
Bottom 3 | Lipo | Power switch output. Use to connect main battery to pyro battery input |
Bottom 4 | A - | A pyro channel connection to pyro circuit |
Bottom 5 | A | A pyro channel common connection to battery |
Bottom 6 | B - | B pyro channel connection to pyro circuit |
Bottom 7 | B | B pyro channel common connection to battery |
Bottom 8 | C - | C pyro channel connection to pyro circuit |
Bottom 9 | C | C pyro channel common connection to battery |
EasyMega provides explicit support for an external pyro battery. All that is required is to remove the jumper between the lipo terminal (Bottom 3) and the pyro terminal (Bottom 2). Then hook the negative pyro battery terminal to ground (Bottom 1) and the positive pyro battery to the pyro battery input (Bottom 2). You can then use the existing pyro screw terminals to hook up all of the pyro charges.
Because EasyMega has built-in support for a separate pyro battery, if you want to fly with just one battery running both the computer and firing the charges, you need to connect the flight computer battery to the pyro circuit. EasyMega has two screw terminals for this—hook a wire from the Lipo terminal (Bottom 3) to the Pyro terminal (Bottom 2).
As explained above, an external active switch requires three connections, one to the positive battery terminal, one to the flight computer positive input and one to ground.
The positive battery terminal is available on Top terminal 1, the positive flight computer input is on Top terminal 2. Ground is on Top terminal 3.
A typical installation involves attaching only a suitable battery, a single pole switch for power on/off, and two pairs of wires connecting e-matches for the apogee and main ejection charges. All Altus Metrum products are designed for use with single-cell batteries with 3.7 volts nominal. EasyMini may also be used with other batteries as long as they supply between 4 and 12 volts.
The battery connectors are a standard 2-pin JST connector; you can purchase suitable batteries from the any vendor selling Altus Metrum products. These batteries are single-cell Lithium Polymer batteries that nominally provide 3.7 volts. Other vendors sell similar batteries for RC aircraft using mating connectors, however the polarity for those is generally reversed from the batteries used by Altus Metrum products. In particular, the Tenergy batteries supplied for use in Featherweight flight computers are not compatible with Altus Metrum flight computers or battery chargers.
Check polarity and voltage before connecting any battery not purchased from Altus Metrum.
Spark Fun sells batteries that have a matching connector with the correct polarity. However, these batteries include an integrated current limiting circuit. That circuit will cause the battery to shut down when firing the igniter circuit. Do not use these batteries unless you remove the current limiting circuit.
By default, we use the unregulated output of the battery directly to fire ejection charges. This works marvelously with standard low-current e-matches like the J-Tek from MJG Technologies, and with Quest Q2G2 igniters. However, if you want or need to use a separate pyro battery, check out Section 3.8, “Using a Separate Pyro Battery” 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.
Except for TeleMini v1.0, the flight computers also use the screw terminal block for the power switch leads. On TeleMini v1.0, the power switch leads are soldered directly to the board and can be connected directly to a switch.
For most air-frames, the integrated antennas are more than adequate. However, if you are installing in a carbon-fiber or metal electronics bay which is opaque to RF signals, you may need to use off-board external antennas instead. In this case, you can replace the stock UHF antenna wire with an edge-launched SMA connector, and, on TeleMetrum v1, you can unplug the integrated GPS antenna and select an appropriate off-board GPS antenna with cable terminating in a U.FL connector.
In the US, you need an amateur radio license or other authorization to legally operate the radio transmitters that are part of our products.
In the rocket itself, you just need a flight computer and a single-cell, 3.7 volt nominal Li-Po rechargeable battery. An 850mAh battery weighs less than a 9V alkaline battery, and will run a TeleMetrum, TeleMega or EasyMega for hours. A 110mAh battery weighs less than a triple A battery and is a good choice for use with TeleMini or EasyMini.
By default, we ship TeleMini, TeleMetrum and TeleMega flight computers with a simple wire antenna. If your electronics bay or the air-frame it resides within is made of carbon fiber, which is opaque to RF signals, you may prefer to install an SMA connector so that you can run a coaxial cable to an antenna mounted elsewhere in the rocket. However, note that the GPS antenna is fixed on all current products, so you really want to install the flight computer in a bay made of RF-transparent materials if at all possible.
To receive the data stream from the rocket, you need an antenna and short feed-line connected to one of our TeleDongle units. If possible, use an SMA to BNC adapter instead of feedline between the antenna feedpoint and TeleDongle, as this will give you the best performance. The TeleDongle in turn plugs directly into the USB port on a notebook computer. Because TeleDongle looks like a simple serial port, your computer does not require special device drivers… just plug it in.
The GUI tool, AltosUI, is written in Java and runs across Linux, Mac OS and Windows. There’s also a suite of C tools for Linux which can perform most of the same tasks.
Alternatively, a TeleBT attached with an SMA to BNC adapter at the feed point of a hand-held yagi used in conjunction with an Android device running AltosDroid makes an outstanding ground station.
After the flight, you can use the radio link to extract the more detailed data logged in either TeleMetrum or TeleMini devices, or you can use a USB cable to plug into the flight computer board directly. A USB cable is also how you charge the Li-Po battery, so 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 rocket lands out of sight, you may enjoy having a hand-held GPS receiver, so that you can put in a way-point for the last reported rocket position before touch-down. This makes looking for your rocket a lot like Geo-Caching… just go to the way-point and look around starting from there. AltosDroid on an Android device with GPS receiver works great for this, too!
You may also enjoy having a ham radio “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 currently uses a Yaesu FT1D, Bdale has a Yaesu VX-7R, which is a nicer radio in most ways but doesn’t support APRS.
So, to recap, on the ground the hardware you’ll need includes:
The best hand-held commercial directional antennas we’ve found for radio direction finding rockets are from Arrow Antennas.
The 440-3 and 440-5 are both good choices for finding a TeleMetrum- or TeleMini- equipped rocket when used with a suitable 70cm HT. TeleDongle and an SMA to BNC adapter fit perfectly between the driven element and reflector of Arrow antennas.
Our software makes it easy to log the data from each flight, both the telemetry received during the flight itself, and the more complete data log recorded in the flash memory on the altimeter board. Once this data is on your computer, our post-flight tools make it easy to quickly get to the numbers everyone wants, like apogee altitude, max acceleration, and max velocity. You can also generate and view a standard set of plots showing the altitude, acceleration, and velocity of the rocket during flight. And you can even export a flight log in a format usable with Google Maps and Google Earth for visualizing the flight path in two or three dimensions!
Our ultimate goal is to emit a set of files for each flight that can be published as a web page per flight, or just viewed on your local disk with a web browser.
We have designed and prototyped several “companion boards” that can attach to the companion connector on TeleMetrum, TeleMega and EasyMega flight computers to collect more data, provide more pyro channels, and so forth. We do not yet know if or when any of these boards will be produced in enough quantity to sell. If you have specific interests for data collection or control of events in your rockets beyond the capabilities of our existing productions, please let us know!
Because all of our work is open, both the hardware designs and the software, if you have some great idea for an addition to the current Altus Metrum family, feel free to dive in and help! Or let us know what 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!
The AltosUI program provides a graphical user interface for interacting with the Altus Metrum product family. AltosUI can monitor telemetry data, configure devices and many other tasks. The primary interface window provides a selection of buttons, one for each major activity in the system. This chapter is split into sections, each of which documents one of the tasks provided from the top-level toolbar.
Selecting this item brings up a dialog box listing all of the connected TeleDongle devices. When you choose one of these, AltosUI will create a window to display telemetry data as received by the selected TeleDongle device.
All telemetry data received are automatically recorded in suitable log files. The name of the files includes the current date and rocket serial and flight numbers.
The radio frequency being monitored by the TeleDongle device is displayed at the top of the window. You can configure the frequency by clicking on the frequency box and selecting the desired frequency. AltosUI remembers the last frequency selected for each TeleDongle and selects that automatically the next time you use that device.
Below the TeleDongle frequency selector, the window contains a few significant pieces of information about the altimeter providing the telemetry data stream:
Finally, the largest portion of the window contains a set of tabs, each of which contain some information about the rocket. They’re arranged in flight order so that as the flight progresses, the selected tab automatically switches to display data relevant to the current state of the flight. You can select other tabs at any time. The final table tab displays all of the raw telemetry values in one place in a spreadsheet-like format.
The Launch Pad tab shows information used to decide when the rocket is ready for flight. The first elements include red/green indicators, if any of these is red, you’ll want to evaluate whether the rocket is ready to launch:
The Launchpad tab also shows the computed launch pad position and altitude, averaging many reported positions to improve the accuracy of the fix.
This tab is shown during Boost, Fast and Coast phases. The information displayed here helps monitor the rocket as it heads towards apogee.
The height, speed, acceleration and tilt are shown along with the maximum values for each of them. This allows you to quickly answer the most commonly asked questions you’ll hear during flight.
The current latitude and longitude reported by the GPS are also shown. Note that under high acceleration, these values may not get updated as the GPS receiver loses position fix. Once the rocket starts coasting, the receiver should start reporting position again.
Finally, the current igniter voltages are reported as in the Launch Pad tab. This can help diagnose deployment failures caused by wiring which comes loose under high acceleration.
Once the rocket has reached apogee and (we hope) activated the apogee charge, attention switches to tracking the rocket on the way back to the ground, and for dual-deploy flights, waiting for the main charge to fire.
To monitor whether the apogee charge operated correctly, the current descent rate is reported along with the current height. Good descent rates vary based on the choice of recovery components, but generally range from 15-30m/s on drogue and should be below 10m/s when under the main parachute in a dual-deploy flight.
With GPS-equipped flight computers, you can locate the rocket in the sky using the elevation and bearing information to figure out where to look. Elevation is in degrees above the horizon. Bearing is reported in degrees relative to true north. Range can help figure out how big the rocket will appear. Ground Distance shows how far it is to a point directly under the rocket and can help figure out where the rocket is likely to land. Note that all of these values are relative to the pad location. If the elevation is near 90°, the rocket is over the pad, not over you.
Finally, the igniter voltages are reported in this tab as well, both to monitor the main charge as well as to see what the status of the apogee charge is. Note that some commercial e-matches are designed to retain continuity even after being fired, and will continue to show as green or return from red to green after firing.
Once the rocket is on the ground, attention switches to recovery. While the radio signal is often lost once the rocket is on the ground, the last reported GPS position is generally within a short distance of the actual landing location.
The last reported GPS position is reported both by latitude and longitude as well as a bearing and distance from the launch pad. The distance should give you a good idea of whether to walk or hitch a ride. Take the reported latitude and longitude and enter them into your hand-held GPS unit and have that compute a track to the landing location.
Our flight computers will continue to transmit RDF tones after landing, allowing you to locate the rocket by following the radio signal if necessary. You may need to get away from the clutter of the flight line, or even get up on a hill (or your 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 may yield more precise results.
To get more detailed information about the flight, you can click on the Graph Flight button which will bring up a graph window for the current flight.
The table view shows all of the data available from the flight computer. Probably the most useful data on this tab is the detailed GPS information, which includes horizontal dilution of precision information, and information about the signal being received from the satellites.
When the TeleMetrum has a GPS fix, the Site Map tab will map the 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 default scale is approximately 3m (10ft) per pixel. The map can be dragged using the left mouse button. The map will attempt to keep the rocket roughly centered while data is being received.
You can adjust the style of map and the zoom level with buttons on the right side of the map window. You can draw a line on the map by moving the mouse over the map with a button other than the left one pressed, or by pressing the left button while also holding down the shift key. The length of the line in real-world units will be shown at the start of the line.
Images are fetched automatically via the Google Maps Static API, and cached on disk for reuse. If map images cannot be downloaded, the 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 Section 11.12, “Load Maps”.
TeleMega includes four additional programmable pyro channels. The Ignitor tab shows whether each of them has continuity. If an ignitor has a low resistance, then the voltage measured here will be close to the pyro battery voltage. A value greater than 3.2V is required for a GO status.
The altimeter records flight data to its internal flash memory. Data logged on board is recorded at a much higher rate than the telemetry system can handle, and is not subject to radio drop-outs. As such, it provides a more complete and precise record of the flight. The Save Flight Data button allows you to read the flash memory and write it to disk.
Clicking on the Save Flight Data button brings up a list of connected flight computers and TeleDongle devices. If you select a flight computer, the flight data will be downloaded from that device directly. If you select a TeleDongle device, flight data will be downloaded from a flight computer over radio link via the specified TeleDongle. See Section A.3, “Controlling An Altimeter Over The Radio Link” for more information.
After the device has been selected, a dialog showing the flight data saved in the device will be shown allowing you to select which flights to download and which to delete. With version 0.9 or newer firmware, you must erase flights in order for the space they consume to be reused by another flight. This prevents accidentally losing flight data if you neglect to download data before flying again. Note that if there is no more space available in the device, then no data will be recorded during the next flight.
The file name for each flight log is computed automatically from the recorded flight date, altimeter serial number and flight number information.
Select this button and you are prompted to select a flight record file, either a .telem file recording telemetry data or a .eeprom file containing flight data saved from the altimeter flash memory.
Once a flight record is selected, the flight monitor interface is displayed and the flight is re-enacted in real time. Check Section 11.1, “Monitor Flight” to learn how this window operates.
Select this button and you are prompted to select a flight record file, either a .telem file recording telemetry data or a .eeprom file containing flight data saved from flash memory.
Note that telemetry files will generally produce poor graphs due to the lower sampling rate and missed telemetry packets. Use saved flight data in .eeprom files for graphing where possible.
Once a flight record is selected, a window with multiple tabs is opened.
By default, the graph contains acceleration (blue), velocity (green) and altitude (red).
The graph can be zoomed into a particular area by clicking and dragging down and to the right. Once zoomed, the graph can be reset by clicking and dragging up and to the left. Holding down control and clicking and dragging allows the graph to be panned. The right mouse button causes a pop-up menu to be displayed, giving you the option save or print the plot.
This selects which graph elements to show, and, at the very bottom. It also lets you configure how the graph is drawn:
Shows overall data computed from the flight.
This tool takes the raw data files and makes them available for external analysis. When you select this button, you are prompted to select a flight data file, which can be either a .eeprom or .telem. The .eeprom files contain higher resolution and more continuous data, while .telem files contain receiver signal strength information. Next, a second dialog appears which is used to select where to write the resulting file. It has a selector to choose between CSV and KML file formats.
This is a text file containing the data in a form suitable for import into a spreadsheet or other external data analysis tool. The first few lines of the file contain the version and configuration information from the altimeter, then there is a single header line which labels all of the fields. All of these lines start with a # character which many tools can be configured to skip over.
The remaining lines of the file contain the data, with each field separated by a comma and at least one space. All of the sensor values are converted to standard units, with the barometric data reported in both pressure, altitude and height above pad units.
Select this button and then select either an altimeter or TeleDongle Device from the list provided. Selecting a TeleDongle device will use the radio link to configure a remote altimeter.
The first few lines of the dialog provide information about the connected device, including the product name, software version and hardware serial number. Below that are the individual configuration entries.
At the bottom of the dialog, there are four buttons:
The rest of the dialog contains the parameters to be configured.
This sets the altitude (above the recorded pad altitude) at which the main igniter will fire. The drop-down menu shows some common values, but you can edit the text directly and choose whatever you like. If the apogee charge fires below this altitude, then the main charge will fire two seconds after the apogee charge fires.
When flying redundant electronics, 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.
Apogee lockout is the number of seconds after boost where the flight computer will not fire the apogee charge, even if the rocket appears to be at apogee. This is often called Mach Delay, as it is intended to prevent a flight computer from unintentionally firing apogee charges due to the pressure spike that occurrs across a mach transition. Altus Metrum flight computers include a Kalman filter which is not fooled by this sharp pressure increase, and so this setting should be left at the default value of zero to disable it.
This configures which of the frequencies to use for both telemetry and packet command mode. Note that if you set this value via packet command mode, the TeleDongle frequency will also be automatically reconfigured to match so that communication will continue afterwards.
The radios in every Altus Metrum device are calibrated at the factory to ensure that they transmit and receive on the specified frequency. If you need to you can adjust the calibration by changing this value. Do not do this without understanding what the value means, read the appendix on calibration and/or the source code for more information. To change a TeleDongle’s calibration, you must reprogram the unit completely.
Enables the radio for transmission during flight. When disabled, the radio will not transmit anything during flight at all.
This sets the modulation bit rate for data transmission for both telemetry and packet link mode. Lower bit rates will increase range while reducing the amount of data that can be sent and increasing battery consumption. All telemetry is done using a rate 1/2 constraint 4 convolution code, so the actual data transmission rate is 1/2 of the modulation bit rate specified here.
How often to transmit GPS information via APRS (in seconds). When set to zero, APRS transmission is disabled. This option is available on TeleMetrum v2 and TeleMega boards. TeleMetrum v1 boards cannot transmit APRS packets. Note that a single APRS packet takes nearly a full second to transmit, so enabling this option will prevent sending any other telemetry during that time.
Which SSID to report in APRS packets. By default, this is set to the last digit of the serial number, but can be configured to any value from 0 to 9.
Whether to send APRS data in Compressed or Uncompressed format. Compressed format is smaller and more precise. Uncompressed format is older, but may work better with your device. The Kenwood TH-D72 only displays altitude information with Uncompressed format, while the Yaesu FT1D only displays altitude with Compressed format. Test before you fly to see which to use.
This sets the call sign included in each telemetry packet. Set this as needed to conform to your local radio regulations.
This sets the space (in kilobytes) allocated for each flight log. The available space will be divided into chunks of this size. A smaller value will allow more flights to be stored, a larger value will record data from longer flights.
This configuration parameter allows the two standard ignitor channels (Apogee and Main) to be used in different configurations.
Because they include accelerometers, TeleMetrum, TeleMega and EasyMega are sensitive to the orientation of the board. By default, they expect the antenna end to point forward. This parameter allows that default to be changed, permitting the board to be mounted with the antenna pointing aft instead.
The beeper on all Altus Metrum flight computers works best at 4000Hz, however if you have more than one flight computer in a single airframe, having all of them sound at the same frequency can be confusing. This parameter lets you adjust the base beeper frequency value.
This sets the amount of motion that TeleGPS needs to see before logging the new position. Motions smaller than this are skipped, which saves storage space.
The interval between TeleGPS position reports, both over the air and in the log. Increase this to reduce the frequency of radio transmissions and the length of time available in the log.
This opens a separate window to recalibrate the accelerometers. Follow the instructions, orienting the flight computer with the antenna end, or end opposite the screw terminals, in the case of EasyMega, first up and then down.
When the calibration is complete, return to the Configure Altimeter window and save the new calibration values.
This opens a separate window to configure the additional pyro channels available on TeleMega and EasyMega. One column is presented for each channel. Each row represents a single parameter, if enabled the parameter must meet the specified test for the pyro channel to be fired.
Select conditions and set the related value; the pyro channel will be activated when all of the conditions are met. Each pyro channel has a separate set of configuration values, so you can use different values for the same condition with different channels.
At the bottom of the window, the Pyro Firing Time configuration sets the length of time (in seconds) which each of these pyro channels will fire for.
Once you have selected the appropriate configuration for all of the necessary pyro channels, you can save the pyro configuration along with the rest of the flight computer configuration by pressing the Save button in the main Configure Flight Computer window.
Because this value is computed by integrating rate gyros, it gets progressively less accurate as the flight goes on. It should have an accumulated error of less than 0.2°/second (after 10 seconds of flight, the error should be less than 2°).
The usual use of the orientation configuration is to ensure that the rocket is traveling mostly upwards when deciding whether to ignite air starts or additional stages. For that, choose a reasonable maximum angle (like 20°) and set the motor igniter to require an angle of less than that value.
The flight software tracks the flight through a sequence of states:
You can select a state to limit when the pyro channel may activate; note that the check is based on when the rocket transitions into the state, and so checking for “greater than Boost” means that the rocket is currently in boost or some later state.
When a motor burns out, the rocket enters either Fast or Coast state (depending on how fast it is moving). If the computer detects upwards acceleration again, it will move back to Boost state.
This button presents a dialog so that you can configure the AltosUI global settings.
AltosUI provides voice announcements during flight so that you can keep your eyes on the sky and still get information about the current flight status. However, sometimes you don’t want to hear them.
AltosUI logs all telemetry data and saves all flash data to this directory. This directory is also used as the staring point when selecting data files for display or export.
Click on the directory name to bring up a directory choosing dialog, select a new directory and click Select Directory to change where AltosUI reads and writes data files.
This value is transmitted in each command packet sent from TeleDongle and received from an altimeter. It is not used in telemetry mode, as the callsign configured in the altimeter board is included in all telemetry packets. Configure this with the AltosUI operators call sign as needed to comply with your local radio regulations.
Note that to successfully command a flight computer over the radio (to configure the altimeter, monitor idle, or fire pyro charges), the callsign configured here must exactly match the callsign configured in the flight computer. This matching is case sensitive.
This switches between metric units (meters) and imperial units (feet and miles). This affects the display of values use during flight monitoring, configuration, data graphing and all of the voice announcements. It does not change the units used when exporting to CSV files, those are always produced in metric units.
This causes all communication with a connected device to be dumped to the console from which AltosUI was started. If 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.
Selects the set of fonts used in the flight monitor window. Choose between the small, medium and large sets.
Switches between the available Java user interface appearances. The default selection is supposed to match the native window system appearance for the target platform.
Selects the initial position for the main AltosUI window that includes all of the command buttons.
Sets the number of map tiles kept in memory while the application is running. More tiles consume more memory, but will make panning around the map faster.
This brings up a dialog where you can configure the set of frequencies shown in the various frequency menus. You can add as many as you like, or even reconfigure the default set. Changing this list does not affect the frequency settings of any devices, it only changes the set of frequencies shown in the menus.
Select this button and then select a TeleDongle or TeleBT Device from the list provided.
The first few lines of the dialog provide information about the connected device, including the product name, software version and hardware serial number. Below that are the individual configuration entries.
Note that TeleDongle and TeleBT don’t save any configuration data, the settings here are recorded on the local machine in the Java preferences database. Moving the device to another machine, or using a different user account on the same machine will cause settings made here to have no effect.
At the bottom of the dialog, there are three buttons:
The rest of the dialog contains the parameters to be configured.
This configures the frequency to use for both telemetry and packet command mode. Set this before starting any operation involving packet command mode so that it will use the right frequency. Telemetry monitoring mode also provides a menu to change the frequency, and that menu also sets the same Java preference value used here.
The radios in every Altus Metrum device are calibrated at the factory to ensure that they transmit and receive on the specified frequency. To change a TeleDongle or TeleBT’s calibration, you must reprogram the unit completely, so this entry simply shows the current value and doesn’t allow any changes.
This reprograms Altus Metrum devices with new firmware. TeleMetrum v1.x, TeleDongle v0.2, TeleMini v1.0 and TeleBT v1.0 are all reprogrammed by using another similar unit as a programming dongle (pair programming). TeleMega, EasyMega, TeleMetrum v2, EasyMini and TeleDongle v3 are all programmed directly over USB (self programming). Please read the directions for flashing devices in Appendix C, Updating Device Firmware.
This activates the igniter circuits in the flight computer to help test recovery systems deployment. Because this command can operate over the Packet Command Link, you can prepare the rocket as for flight and then test the recovery system without needing to snake wires inside the air-frame.
Selecting the Fire Igniter button brings up the usual device selection dialog. Pick the desired device. This brings up another window which shows the current continuity test status for all of the pyro channels.
Next, select the desired igniter to fire. This will enable the Arm button.
Select the Arm button. This enables the Fire button. The word Arm is replaced by a countdown timer indicating that you have 10 seconds to press the Fire button or the system will deactivate, at which point you start over again at selecting the desired igniter.
This listens for telemetry packets on all of the configured frequencies, displaying information about each device it receives a packet from. You can select which of the baud rates and telemetry formats should be tried; by default, it only listens at 38400 baud with the standard telemetry format used in v1.0 and later firmware.
Before heading out to a new launch site, you can use this to load satellite images in case you don’t have internet connectivity at the site.
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 from our server 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
There are four different kinds of maps you can view; you can select which to download by selecting as many as you like from the available types:
You can specify the range of zoom levels to download; smaller numbers show more area with less resolution. The default level, 0, shows about 3m/pixel. One zoom level change doubles or halves that number. Larger zoom levels show more detail, smaller zoom levels less.
The Map Radius value sets how large an area around the center point to download. Select a value large enough to cover any plausible flight from that site. Be aware that loading a large area with a high maximum zoom level can attempt to download a lot of data. Loading hybrid maps with a 10km radius at a minimum zoom of -2 and a maximum zoom of 2 consumes about 120MB of space. Terrain and road maps consume about 1/10 as much space as satellite or hybrid maps.
Clicking the Load Map button will fetch images from Google Maps; note that Google limits how many images you can fetch at once, so if you load more than one launch site, you may get some gray areas in the map which indicate that Google is tired of sending data to you. Try again later.
This brings up a dialog similar to the Monitor Flight UI, except it works with the altimeter in “idle” mode by sending query commands to discover the current state rather than listening for telemetry packets. Because this uses command mode, it needs to have the TeleDongle and flight computer callsigns match exactly. If you can receive telemetry, but cannot manage to run Monitor Idle, then it’s very likely that your callsigns are different in some way.
You can change the frequency and callsign used to communicate with the flight computer; they must both match the configuration in the flight computer exactly.
AltosDroid provides the same flight monitoring capabilities as AltosUI, but runs on Android devices. AltosDroid is designed to connect to a TeleBT receiver over Bluetooth™ and (on Android devices supporting USB On-the-go) TeleDongle and TeleBT devices over USB. AltosDroid monitors telemetry data, logging it to internal storage in the Android device, and presents that data in a UI similar to the Monitor Flight window in AltosUI.
This manual will explain how to configure AltosDroid, connect to TeleBT or TeleDongle, operate the flight monitoring interface and describe what the displayed data means.
AltosDroid is available from the Google Play store. To install it on your Android device, open the Google Play Store application and search for “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.
Before using TeleBT with AltosDroid, make sure the internal TeleBT battery is charged. To do this, attach a micro USB cable from a computer or other USB power source to TeleBT. A dual LED on the circuit board should illuminate, showing red while the battery is charging, green when charging is completed, and both red and green on at the same time if there is a battery fault.
Press the Android Menu button or soft-key to see the configuration options available. Select the Connect a device option and then the Scan for devices entry at the bottom to look for your TeleBT device. Select your device, and when it asks for the code, enter 1234.
Subsequent connections will not require you to enter that code, and your paired device will appear in the list without scanning.
Get a special USB On-the-go adapter cable. These cables have a USB micro-B male connector on one end and a standard A female connector on the other end. Plug in your TeleDongle or TeleBT device to the adapter cable and the adapter cable into your phone and AltosDroid should automatically start up. If it doesn’t, the most likely reason is that your Android device doesn’t support USB On-the-go.
The main AltosDroid menu has a selection of operation and configuration options.
AltosDroid is designed to mimic the AltosUI flight monitoring display, providing separate tabs for each stage of your rocket flight along with a tab containing a map of the local area with icons marking the current location of the altimeter and the Android device.
The Pad tab shows information used to decide when the rocket is ready for flight. The first elements include red/green indicators, if any of these is red, you’ll want to evaluate whether the rocket is ready to launch.
When the pad tab is selected, the voice responses will include status changes to the igniters and GPS reception, letting you know if the rocket is still ready for launch.
The Pad tab also shows the location of the Android device.
The Flight tab shows information used to evaluate and spot a rocket while in flight. It displays speed and height data to monitor the health of the rocket, along with elevation, range and bearing to help locate the rocket in the sky.
While the Flight tab is displayed, the voice announcements will include current speed, height, elevation and bearing information.
The Recover tab shows information used while recovering the rocket on the ground after flight.
While the Recover tab is displayed, the voice announcements will include distance along with either bearing or direction, depending on whether you are moving.
The Map tab shows a map of the area around the rocket being tracked along with information needed to recover it.
On the map itself, icons showing the location of the android device along with the last known location of each tracker. A blue line is drawn from the android device location to the currently selected tracker.
Below the map, the distance and either bearing or direction along with the lat/lon of the target and the android device are shown
The Map tab provides the same voice announcements as the Recover tab.
AltosDroid always saves every bit of telemetry data it receives. To download that to a computer for use with AltosUI, remove the SD card from your Android device, or connect your device to your 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.
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, TeleMega and EasyMega, which have accelerometers, 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 the flight computer 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 EasyMini doesn’t have an accelerometer we can use to determine orientation, “idle” mode is selected if the board is connected via USB to a computer, otherwise the board enters “flight” mode. TeleMini selects “idle” mode if it receives a command packet within the first five seconds of operation.
At power on, the altimeter will beep out the battery voltage to the nearest tenth of a volt. Each digit is represented by a sequence of short “dit” beeps, with a pause between digits. A zero digit is represented with one long “dah” beep. Then there will be a short pause while the altimeter completes initialization and self test, and decides which mode to enter next.
In flight or “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 which is made by rapidly alternating between two tones 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 in idle mode over either USB or the radio link equivalently. TeleMini only has the radio link. Idle mode is useful for configuring the altimeter, for extracting data from the on-board storage chip after flight, and for ground testing pyro charges.
In “Idle” and “Pad” modes, once the mode indication beeps/flashes and continuity indication has been sent, if there is no space available to log the flight in on-board memory, the flight computer will emit a warbling tone (much slower than the “no continuity tone”)
See Section 3.5, “Understanding Beeps” for a summary of all of the audio signals used.
Once landed, the flight computer will signal that by emitting the “Landed” sound described above, after which it will beep out the apogee height (in meters). Each digit is represented by a sequence of short “dit” beeps, with a pause between digits. A zero digit is represented with one long “dah” beep. The flight computer will continue to report landed mode and beep out the maximum height until turned off.
One “neat trick” of particular value when TeleMetrum, TeleMega or EasyMega are used with very large air-frames, is that you can power the board up while the rocket is horizontal, such that it comes up in idle mode. Then you can raise the air-frame to launch position, and issue a reset command via TeleDongle over the radio link to cause the altimeter to reboot and come up in flight mode. This is much safer than standing on the top step of a rickety step-ladder or hanging off the side of a launch tower with a screw-driver trying to turn on your avionics before installing igniters!
TeleMini is configured solely via the radio link. Of course, that means you need to know the TeleMini radio configuration values or you won’t be able to communicate with it. For situations when you don’t have the radio configuration values, TeleMini v1.0 offers an emergency recovery mode. In this mode, TeleMini v1.0 is configured as follows:
To get into emergency recovery mode, first find the row of four small holes opposite the switch wiring. Using a short piece of small gauge wire, connect the outer two holes together, then power TeleMini up. Once the red LED is lit, disconnect the wire and the board should signal that it’s in idle mode after the initial five second startup period.
TeleMetrum and TeleMega include a complete GPS receiver. A complete explanation of how GPS works is beyond the scope of this manual, but the bottom line is that the GPS receiver needs to lock onto at least four satellites to obtain a solid 3 dimensional position fix and know what time it is.
The flight computers provide backup power to the GPS chip any time a battery is connected. This allows the receiver to “warm start” on the launch rail much faster than if every power-on were a GPS “cold start”. In typical operations, powering up on the flight line in idle mode while performing final air-frame preparation will be sufficient to allow the GPS receiver to cold start and acquire lock. Then the board can be powered down during RSO review and installation on a launch rod or rail. When the board is turned back on, the GPS system should lock very quickly, typically long before igniter installation and return to the flight line are complete.
One of the unique features of the Altus Metrum system is the ability to create a two way command link between TeleDongle and an altimeter using the digital radio transceivers built into each device. This allows you to interact with the altimeter from afar, as if it were directly connected to the computer.
Any operation which can be performed with a flight computer can either be done with the device directly connected to the computer via the USB cable, or through the radio link. TeleMini 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.
Operation over the radio link for configuring an altimeter, ground testing igniters, and so forth uses the same RF frequencies as flight telemetry. To configure the desired TeleDongle frequency, select the monitor flight tab, then use the frequency selector and close the window before performing other desired radio operations.
The flight computers only enable radio commanding in idle mode. TeleMetrum and TeleMega use the accelerometer to detect which orientation they start up in, so make sure you have the flight computer lying horizontally when you turn it on. Otherwise, it will start in pad mode ready for flight, and will not be listening for command packets from TeleDongle.
TeleMini listens for a command packet for five seconds after first being turned on, if it 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.
An important aspect of preparing a rocket using electronic deployment for flight is ground testing the recovery system. Thanks to the bi-directional radio link central to the Altus Metrum system, this can be accomplished in a TeleMega, TeleMetrum or TeleMini equipped rocket with less work than you may be accustomed to with other systems. It can even be fun!
Just prep the rocket for flight, then power up the altimeter in “idle” mode (placing air-frame horizontal for TeleMetrum or TeleMega, or selecting the Configure Altimeter tab for TeleMini). This will cause the firmware to go into “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 the Fire Igniter tab to complete ejection testing.
TeleMetrum, TeleMini and TeleMega all incorporate 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 generally 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 forward error correction and interleaving, this allows us to have a very robust 19.2 kilobit data link with only 10-40 milliwatts of transmit power, a whip antenna in the rocket, and a hand-held Yagi on the ground. 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 with our 10mW units and over 100k feet AGL with the 40mW devices. We hope to fly boards to higher altitudes over time, and would of course appreciate customer feedback on performance in higher altitude flights!
TeleMetrum v2.0 and TeleMega can send APRS if desired, and the interval between APRS packets can be configured. As each APRS packet takes a full second to transmit, we recommend an interval of at least 5 seconds to avoid consuming too much battery power or radio channel bandwidth. You can configure the APRS interval using AltosUI; that process is described in Section 11.6, “Configure Altimeter”.
AltOS supports both compressed and uncompressed APRS position report data formats. The compressed format provides for higher position precision and shorter packets than the uncompressed APRS format. We’ve found some older APRS receivers that do not handle the compressed format. The Kenwood TH-72A requires the use of uncompressed format to display altitude information correctly. The Yaesu FT1D requires the use of compressed format to display altitude information.
APRS packets include an SSID (Secondary Station Identifier) field that allows one operator to have multiple transmitters. AltOS allows you to set this to a single digit from 0 to 9, allowing you to fly multiple transmitters at the same time while keeping the identify of each one separate in the receiver. By default, the SSID is set to the last digit of the device serial number.
The APRS packet format includes a comment field that can have arbitrary text in it. AltOS uses this to send status information as shown in the following table.
Table A.1. Altus Metrum APRS Comments
Field | Example | Description |
---|---|---|
1 | L | GPS Status U for unlocked, L for locked |
2 | 6 | Number of Satellites in View |
3 | B4.0 | Altimeter Battery Voltage |
4 | A3.7 | Apogee Igniter Voltage |
5 | M3.7 | Main Igniter Voltage |
6 | 1286 | Device Serial Number |
4 | 1286 | Device Serial Number |
Here’s an example of an APRS comment showing GPS lock with 6 satellites in view, a primary battery at 4.0V, and apogee and main igniters both at 3.7V from device 1286.
L6 B4.0 A3.7 M3.7 1286
Here’s an example of an APRS comment showing GPS lock with 6 satellites in view and a primary battery at 4.0V from device 1876.
L6 B4.0 1876
Make sure your primary battery is above 3.8V any connected igniters are above 3.5V and GPS is locked with at least 5 or 6 satellites in view before flying. If GPS is switching between L and U regularly, then it doesn’t have a good lock and you should wait until it becomes stable.
If the GPS receiver loses lock, the APRS data transmitted will contain the last position for which GPS lock was available. You can tell that this has happened by noticing that the GPS status character switches from L to U. Before GPS has locked, APRS will transmit zero for latitude, longitude and altitude.
Configuring an Altus Metrum altimeter for flight is very simple. Even on our baro-only TeleMini and EasyMini boards, the use of a Kalman filter means there is no need to set a “mach delay”. All of the configurable parameters can be set using AltosUI. Read Section 11.6, “Configure Altimeter” for more information.
All Altus Metrum products are sophisticated electronic devices. When handled gently and properly installed in an air-frame, they will deliver impressive results. However, as with all electronic devices, there are some precautions you must take.
The Lithium Polymer rechargeable batteries have an extraordinary power density. This is great because we can fly with much less battery mass than if we used alkaline batteries or previous generation rechargeable batteries… but if they are punctured or their leads are allowed to short, they can and will release their energy very rapidly! Thus we recommend that you take some care when handling our batteries and consider giving them some extra protection in your air-frame. We often wrap them in suitable scraps of closed-cell packing foam before strapping them down, for example.
The barometric sensors used on all of our flight computers are sensitive to sunlight. In normal mounting situations, the baro sensor and all of the other surface mount components are “down” towards whatever the underlying mounting surface is, so this is not normally a problem. Please consider this when designing an installation in an air-frame with a see-through plastic payload bay. It is particularly important to consider this with TeleMini v1.0, both because the baro sensor is on the “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.
TeleMega, TeleMetrum v2, EasyMega, EasyMini and TeleDongle v3 are all programmed directly over their USB connectors (self programming). TeleMetrum v1, TeleMini v1.0 and TeleDongle v0.2 are all programmed by using another device as a programmer (pair programming). It’s important to recognize which kind of devices you have before trying to reprogram them.
You may wish to begin by ensuring you have current firmware images. These are distributed as part of the AltOS software bundle that also includes the AltosUI ground station program. Newer ground station versions typically work fine with older firmware versions, so you don’t need to update your devices just to try out new software features. You can always download the most recent version from http://www.altusmetrum.org/AltOS/
Self-programmable devices are reprogrammed by connecting them to your computer over USB.
If the firmware loading fails, it can leave the device unable to boot. Not to worry, you can force the device to start the boot loader instead, which will let you try to flash the device again.
On each device, connecting two pins from one of the exposed connectors will force the boot loader to start, even if the regular operating system has been corrupted in some way.
Once you’ve located the right pins:
The board should now be visible over USB as AltosFlash and be ready to receive firmware. Once the board has been powered up, you can remove the piece of wire.
The big concept to understand is that you have to use a TeleMetrum v1.0, TeleBT v1.0 or TeleDongle v0.2 as a programmer to update a pair programmed device. Due to limited memory resources in the cc1111, we don’t support programming directly over USB for these devices.
If you need to update the firmware on a TeleDongle v0.2, we recommend updating the altimeter first, before updating TeleDongle. However, note that TeleDongle rarely need to be updated. Any firmware version 1.0.1 or later will work, version 1.2.1 may have improved receiver performance slightly.
If something goes wrong, give it another try.
You’ll need a special programming cable to reprogram the TeleMini v1.0. You can make your own using an 8-pin MicroMaTch connector on one end and a set of four pins on the other.
If something goes wrong, give it another try.
Updating TeleDongle v0.2 firmware is just like updating TeleMetrum v1.x or TeleMini v1.0 firmware, but you use either a TeleMetrum v1.x, TeleDongle v0.2 or TeleBT v1.0 as the programmer.
If something goes wrong, give it another try.
Be careful removing the programming cable from the locking 8-pin connector on TeleMetrum. 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.
Each flight computer logs data at 100 samples per second during ascent and 10 samples per second during descent, except for TeleMini v1.0, which records ascent at 10 samples per second and descent at 1 sample per second. Data are logged to an on-board flash memory part, which can be partitioned into several equal-sized blocks, one for each flight.
Table D.1. Data Storage on Altus Metrum altimeters
Device | Bytes per Sample | Total Storage | Minutes at Full Rate |
---|---|---|---|
TeleMetrum v1.0 | 8 | 1MB | 20 |
TeleMetrum v1.1 v1.2 | 8 | 2MB | 40 |
TeleMetrum v2.0 | 16 | 8MB | 80 |
TeleMini v1.0 | 2 | 5kB | 4 |
TeleMini v3.0 | 16 | 512kB | 5 |
EasyMini | 16 | 1MB | 10 |
TeleMega | 32 | 8MB | 40 |
EasyMega | 32 | 8MB | 40 |
The on-board flash is partitioned into separate flight logs, each of a fixed maximum size. Increase the maximum size of each log and you reduce the number of flights that can be stored. Decrease the size and you can store more flights.
Configuration data is also stored in the flash memory on TeleMetrum v1.x, TeleMini v3.0 and EasyMini. This consumes 64kB of flash space. This configuration space is not available for storing flight log data.
TeleMetrum v2.0, TeleMega and EasyMega store configuration data in a bit of eeprom available within the processor chip, leaving that space available in flash for more flight data.
To compute the amount of space needed for a single flight, you can multiply the expected ascent time (in seconds) by 100 times bytes-per-sample, multiply the expected descent time (in seconds) by 10 times the bytes per sample and add the two together. That will slightly under-estimate the storage (in bytes) needed for the flight. For instance, a TeleMetrum v2.0 flight spending 20 seconds in ascent and 150 seconds in descent will take about (20 * 1600) + (150 * 160) = 56000 bytes of storage. You could store dozens of these flights in the on-board flash.
The default size allows for several flights on each flight computer, except for TeleMini v1.0, which only holds data for a single flight. You can adjust the size.
Altus Metrum flight computers will not overwrite existing flight data, so be sure to download flight data and erase it from the flight computer before it fills up. The flight computer will still successfully control the flight even if it cannot log data, so the only thing you will lose is the data.
Here’s the full set of Altus Metrum products, both in production and retired.
Table E.1. Altus Metrum Flight Computer Electronics
Device | Barometer | Z-axis accel | GPS | 3D sensors | Storage | RF Output | Battery |
---|---|---|---|---|---|---|---|
TeleMetrum v1.0 | MP3H6115 10km (33k') | MMA2202 50g | SkyTraq | - | 1MB | 10mW | 3.7V |
TeleMetrum v1.1 | MP3H6115 10km (33k') | MMA2202 50g | SkyTraq | - | 2MB | 10mW | 3.7V |
TeleMetrum v1.2 | MP3H6115 10km (33k') | ADXL78 70g | SkyTraq | - | 2MB | 10mW | 3.7V |
TeleMetrum v2.0 | MS5607 30km (100k') | MMA6555 102g | uBlox Max-7Q | - | 8MB | 40mW | 3.7V |
TeleMini v1.0 | MP3H6115 10km (33k') | - | - | - | 5kB | 10mW | 3.7V |
TeleMini v3.0 | MS5607 30km (100k') | - | - | - | 512kB | 40mW | 3.7V |
EasyMini v1.0 | MS5607 30km (100k') | - | - | - | 1MB | - | 3.7-12V |
TeleMega v1.0 | MS5607 30km (100k') | MMA6555 102g | uBlox Max-7Q | MPU6000 HMC5883 | 8MB | 40mW | 3.7V |
TeleMega v2.0 | MS5607 30km (100k') | MMA6555 102g | uBlox Max-7Q | MPU6000 HMC5883 | 8MB | 40mW | 3.7V |
EasyMega v1.0 | MS5607 30km (100k') | MMA6555 102g | - | MPU6000 HMC5883 | 8MB | - | 3.7V |
Table E.2. Altus Metrum Flight Computer Mechanical Components
Device | Connectors | Screw Terminals | Width | Length | Tube Size |
---|---|---|---|---|---|
TeleMetrum | Antenna Debug Companion USB Battery | Apogee pyro Main pyro Switch | 1 inch (2.54cm) | 2 ¾ inch (6.99cm) | 29mm coupler |
TeleMini v1.0 | Antenna Debug Battery | Apogee pyro Main pyro | ½ inch (1.27cm) | 1½ inch (3.81cm) | 18mm coupler |
TeleMini v2.0 | Antenna Debug USB Battery | Apogee pyro Main pyro Battery Switch | 0.8 inch (2.03cm) | 1½ inch (3.81cm) | 24mm coupler |
EasyMini | Debug USB Battery | Apogee pyro Main pyro Battery | 0.8 inch (2.03cm) | 1½ inch (3.81cm) | 24mm coupler |
TeleMega | Antenna Debug Companion USB Battery | Apogee pyro Main pyro Pyro A-D Switch Pyro battery | 1¼ inch (3.18cm) | 3¼ inch (8.26cm) | 38mm coupler |
EasyMega | Debug Companion USB Battery | Apogee pyro Main pyro Pyro A-D Switch Pyro battery | 1¼ inch (3.18cm) | 2¼ inch (5.62cm) | 38mm coupler |
Version 1.8.3 includes support for TeleMega version 3.0 along with two important flight computer fixes. This version also changes KML export data to make Tripoli Record reporting better and some updates to graph presentation and data downloading.
Version 1.8.2 includes support for TeleGPS version 2.0 along with accelerometer recalibration support in AltosUI.
1.8.2 also contains a couple of minor fixes for AltosUI when analyzing saved data files.
Version 1.8.1 includes an important bug fix for Apogee Lockout operation in all flight computers. Anyone using this option must update firmware.
This release also contains a change in how flight computers with accelerometers deal with speeds around and above Mach 1. In previous versions, the flight computer would completely disregard the barometric sensor above 330m/s (around Mach 1). Now, the data from the barometric sensor is reduced in effect without ever going away entirely. This prevents early drogue deployment for flights which spend considerable time above Mach 1.
1.8.1 also contains a couple of minor fixes for AltosUI when analyzing saved data files.
AltOS Bug Fixes
AltosUI New Features
AltosUI Bug Fixes
Version 1.8 includes support for our new TeleBT v4.0 ground station, updates for data analysis in our ground station software and bug fixes in in the flight software for all our boards and ground station interfaces.
AltosUI New Features
AltosUI Bug Fixes
Version 1.7 includes support for our new TeleMini v3.0 flight computer and bug fixes in in the flight software for all our boards and ground station interfaces.
AltOS New Features
AltOS Fixes
Version 1.6.8 fixes a TeleMega and TeleMetrum v2.0 bug where the device could stop logging data and transmitting telemetry in flight. All TeleMega v1.0, v2.0 and TeleMetrum v2.0 users should update their flight firmware.
AltOS fixes:
AltOS changes:
AltosUI fixes:
Version 1.6.5 fixes a TeleMega and TeleMetrum v2.0 bug where the device would often stop logging data and transmitting telemetry in flight. All TeleMega v1.0, v2.0 and TeleMetrum v2.0 users should update their flight firmware.
AltOS fixes:
Version 1.6.4 fixes a bluetooth communication problem with TeleBT v1.0 devices, along with some altosui and altosdroid minor nits. It also now ships firmware for some newer devices.
AltOS fixes:
AltosUI, TeleGPS and AltosDroid New Features:
AltosUI, TeleGPS and AltosDroid Fixes:
Version 1.6.3 adds idle mode to AltosDroid and has bug fixes for our host software on desktops, laptops an android devices along with BlueTooth support for Windows.
AltOS fixes:
AltosUI and TeleGPS New Features:
AltosUI and TeleGPS Fixes:
AltosDroid new features:
AltosDroid bug fixes:
Version 1.6.2 includes support for our updated TeleMega v2.0 product and bug fixes in in the flight software for all our boards and ground station interfaces.
AltOS New Features:
AltOS Fixes:
AltosUI and TeleGPS Fixes:
We spent a bunch of time trying to improve our documentation
Version 1.6.1 includes support for our updated TeleBT v3.0 product and bug fixes in in the flight software for all our boards and ground station interfaces.
AltOS New Features:
AltOS Fixes:
AltosUI and TeleGPS New Features:
AltosUI and TeleGPS Fixes:
AltosDroid New Features:
AltosDroid Fixes:
Version 1.6 includes support for our updated TeleDongle v3.0 product and bug fixes in in the flight software for all our boards and ground station interfaces.
AltOS New Features
AltOS Fixes
AltosUI and TeleGPS New Features
AltosUI Fixes
Version 1.5 is a major release. It includes support for our new EasyMega product, new features and bug fixes in in the flight software for all our boards and the AltosUI ground station
AltOS New Features
AltOS Fixes
AltosUI and TeleGPS New Features
AltosUI Fixes
Version 1.4.2 is a minor release. It fixes Java-related install issues on Windows
Version 1.4.1 is a minor release. It fixes install issues on Windows and provides the missing TeleMetrum V2.0 firmware. There aren’t any changes to the firmware or host applications at all. All Windows users will want to upgrade to get the signed driver, but Mac and Linux users who do not need the TeleMetrum V2.0 firmware image will not need to upgrade.
Windows Install Fixes
Other Fixes
Version 1.4 is a major release. It includes support for our new TeleGPS product, new features and bug fixes in in the flight software for all our boards and the AltosUI ground station
AltOS new features:
AltOS fixes:
AltosUI new features:
AltosUI fixes:
Documentation changes:
Version 1.3.2 is a minor release. It includes small bug fixes for the TeleMega flight software and AltosUI ground station
AltOS fixes:
AltosUI fixes:
Version 1.3.1 is a minor release. It improves support for TeleMega, TeleMetrum v2.0, TeleMini v2.0 and EasyMini.
AltOS new features:
AltOS fixes:
AltosUI new features:
AltosUI fixes:
Version 1.3 is a major release. It adds support for TeleMega, TeleMetrum v2.0, TeleMini v2.0 and EasyMini.
AltOS new features:
AltosUI new features:
AltosUI fixes:
Version 1.2.1 is a minor release. It adds support for TeleBT and the AltosDroid application, provides several new features in AltosUI and fixes some bugs in the AltOS firmware.
AltOS new features:
AltOS fixes:
AltosUI application new features:
AltosUI application fixes:
Version 1.2 is a major release. It adds support for MicroPeak and the MicroPeak USB adapter.
AltOS New Features:
New Features:
AltosUI and MicroPeak fixes:
Version 1.1.1 is a bug-fix release. It fixes a couple of bugs in AltosUI and one firmware bug that affects TeleMetrum version 1.0 boards. Thanks to Bob Brown for help diagnosing the Google Earth file export issue, and for suggesting the addition of the Ground Distance value in the Descent tab.
AltOS fixes:
AltosUI new features:
AltosUI fixes:
Version 1.1 is a minor release. It provides a few new features in AltosUI and the AltOS firmware and fixes bugs.
AltOS Firmware New Features:
AltOS Fixes:
AltosUI New Features:
AltosUI Fixes:
Version 1.0.1 is a major release, adding support for the TeleMini device and lots of new AltosUI features
AltOS New Features
AltOS Fixes
AltosUI New Features
AltosUI Changes
Version 0.9.2 is an AltosUI bug-fix release, with no firmware changes.
Version 0.9 adds a few new firmware features and accompanying AltosUI changes, along with new hardware support.
Version 0.8 offers a major upgrade in the AltosUI interface.
Version 0.7.1 is the first release containing our new cross-platform Java-based user interface.