--- /dev/null
+<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>TeleMetrum</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="book" title="TeleMetrum"><div class="titlepage"><div><div><h1 class="title"><a name="id2276207"></a>TeleMetrum</h1></div><div><h2 class="subtitle">Owner's Manual for the TeleMetrum System</h2></div><div><div class="author"><h3 class="author"><span class="firstname">Bdale</span> <span class="surname">Garbee</span></h3></div></div><div><div class="author"><h3 class="author"><span class="firstname">Keith</span> <span class="surname">Packard</span></h3></div></div><div><p class="copyright">Copyright © 2010 Bdale Garbee and Keith Packard</p></div><div><div class="legalnotice" title="Legal Notice"><a name="id2559812"></a><p>
+ This document is released under the terms of the
+ <a class="ulink" href="http://creativecommons.org/licenses/by-sa/3.0/" target="_top">
+ Creative Commons ShareAlike 3.0
+ </a>
+ license.
+ </p></div></div><div><div class="revhistory"><table border="1" width="100%" summary="Revision history"><tr><th align="left" valign="top" colspan="2"><b>Revision History</b></th></tr><tr><td align="left">Revision 0.3</td><td align="left">12 November 2010</td></tr><tr><td align="left" colspan="2">
+ Add instructions for re-flashing devices using AltosUI
+ </td></tr><tr><td align="left">Revision 0.2</td><td align="left">18 July 2010</td></tr><tr><td align="left" colspan="2">Significant update</td></tr><tr><td align="left">Revision 0.1</td><td align="left">30 March 2010</td></tr><tr><td align="left" colspan="2">Initial content</td></tr></table></div></div></div><hr></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="chapter"><a href="#id2555013">1. Introduction and Overview</a></span></dt><dt><span class="chapter"><a href="#id2540100">2. Getting Started</a></span></dt><dd><dl><dt><span class="section"><a href="#id2559795">FAQ</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id2546901">3. Specifications</a></span></dt><dt><span class="chapter"><a href="#id2574755">4. Handling Precautions</a></span></dt><dt><span class="chapter"><a href="#id2547133">5. Hardware Overview</a></span></dt><dt><span class="chapter"><a href="#id2552998">6. Operation</a></span></dt><dd><dl><dt><span class="section"><a href="#id2556146">Firmware Modes </a></span></dt><dt><span class="section"><a href="#id2557858">GPS </a></span></dt><dt><span class="section"><a href="#id2572262">Ground Testing </a></span></dt><dt><span class="section"><a href="#id2572259">Radio Link </a></span></dt><dt><span class="section"><a href="#id2542980">Configurable Parameters</a></span></dt><dd><dl><dt><span class="section"><a href="#id2563251">Radio Channel</a></span></dt><dt><span class="section"><a href="#id2554165">Apogee Delay</a></span></dt><dt><span class="section"><a href="#id2571971">Main Deployment Altitude</a></span></dt></dl></dd><dt><span class="section"><a href="#id2550600">Calibration</a></span></dt><dd><dl><dt><span class="section"><a href="#id2574322">Radio Frequency</a></span></dt><dt><span class="section"><a href="#id2564433">Accelerometer</a></span></dt></dl></dd></dl></dd><dt><span class="chapter"><a href="#id2554553">7. Updating Device Firmware</a></span></dt><dd><dl><dt><span class="section"><a href="#id2569887">Updating TeleMetrum Firmware</a></span></dt><dt><span class="section"><a href="#id2552683">Updating TeleDongle Firmware</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id2539483">8. Using Altus Metrum Products</a></span></dt><dd><dl><dt><span class="section"><a href="#id2558109">Being Legal</a></span></dt><dd><dl><dt><span class="section"><a href="#id2554650">In the Rocket</a></span></dt><dt><span class="section"><a href="#id2572268">On the Ground</a></span></dt><dt><span class="section"><a href="#id2569008">Data Analysis</a></span></dt><dt><span class="section"><a href="#id2563568">Future Plans</a></span></dt></dl></dd><dt><span class="section"><a href="#id2567979">
+ How GPS Works
+ </a></span></dt></dl></dd></dl></div><div class="chapter" title="Chapter 1. Introduction and Overview"><div class="titlepage"><div><div><h2 class="title"><a name="id2555013"></a>Chapter 1. Introduction and Overview</h2></div></div></div><p>
+ 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!
+ </p><p>
+ The focal point of our community is 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.
+ </p><p>
+ Complementing TeleMetrum is TeleDongle, a USB to RF interface for
+ communicating with TeleMetrum. 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.
+ </p><p>
+ 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.
+ </p></div><div class="chapter" title="Chapter 2. Getting Started"><div class="titlepage"><div><div><h2 class="title"><a name="id2540100"></a>Chapter 2. Getting Started</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id2559795">FAQ</a></span></dt></dl></div><p>
+ This chapter began as "The Mere-Mortals Quick Start/Usage Guide to
+ the Altus Metrum Starter Kit" by Bob Finch, W9YA, NAR 12965, TRA 12350,
+ w9ya@amsat.org. Bob was one of our first customers for a production
+ TeleMetrum, and the enthusiasm that led to his contribution of this
+ section is immensely gratifying and highy appreciated!
+ </p><p>
+ The first thing to do after you check the inventory of parts in your
+ "starter kit" is to charge the battery by plugging it into the
+ corresponding socket of the TeleMetrum and then using the USB A to B
+ cable to plug the Telemetrum into your computer's USB socket. The
+ TeleMetrum circuitry will charge the battery whenever it is plugged
+ into the usb socket. The TeleMetrum's on-off switch does NOT control
+ the charging circuitry. When the GPS chip is initially searching for
+ satellites, the unit will pull more current than it can pull from the
+ usb port, so the battery must be plugged in order to get a good
+ 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.
+ </p><p>
+ The other active device in the starter kit is the half-duplex TeleDongle
+ rf link. If you plug it in to your computer it should "just work",
+ showing up as a serial port device. If you are using Linux and are
+ having problems, try moving to a fresher kernel (2.6.33 or newer), as
+ there were some ugly USB serial driver bugs in earlier versions.
+ </p><p>
+ Next you should obtain and install the AltOS utilities. The first
+ generation sofware was written for Linux only. New software is coming
+ soon that will also run on Windows and Mac. For now, we'll concentrate
+ on Linux. If you are using Debian, an 'altos' package already exists,
+ see http://altusmetrum.org/AltOS for details on how to install it.
+ User-contributed directions for building packages on ArchLinux may be
+ found in the contrib/arch-linux directory as PKGBUILD files.
+ Between the debian/rules file and the PKGBUILD files in
+ contrib, you should find enough information to learn how to build the
+ software for any other version of Linux.
+ </p><p>
+ When you have successfully installed the software suite (either from
+ compiled source code or as the pre-built Debian package) you will
+ have 10 or so executable programs all of which have names beginning
+ with 'ao-'.
+ ('ao-view' is the lone GUI-based program, the rest are command-line
+ oriented.) You will also have man pages, that give you basic info
+ on each program.
+ You will also get this documentation in two file types in the doc/
+ directory, telemetrum-doc.pdf and telemetrum-doc.html.
+ Finally you will have a couple control files that allow the ao-view
+ GUI-based program to appear in your menu of programs (under
+ the 'Internet' category).
+ </p><p>
+ Both Telemetrum and TeleDongle can be directly communicated
+ with using USB ports. The first thing you should try after getting
+ both units plugged into to your computer's usb port(s) is to run
+ 'ao-list' from a terminal-window to see what port-device-name each
+ device has been assigned by the operating system.
+ You will need this information to access the devices via their
+ respective on-board firmware and data using other command line
+ programs in the AltOS software suite.
+ </p><p>
+ To access the device's firmware for configuration you need a terminal
+ program such as you would use to talk to a modem. The software
+ authors prefer using the program 'cu' which comes from the UUCP package
+ on most Unix-like systems such as Linux. An example command line for
+ cu might be 'cu -l /dev/ttyACM0', substituting the correct number
+ indicated from running the
+ ao-list program. Another reasonable terminal program for Linux is
+ 'cutecom'. The default 'escape'
+ character used by CU (i.e. the character you use to
+ issue commands to cu itself instead of sending the command as input
+ to the connected device) is a '~'. You will need this for use in
+ only two different ways during normal operations. First is to exit
+ the program by sending a '~.' which is called a 'escape-disconnect'
+ and allows you to close-out from 'cu'. The
+ second use will be outlined later.
+ </p><p>
+ Both TeleMetrum and TeleDongle share the concept of a two level
+ command set in their firmware.
+ The first layer has several single letter commands. Once
+ you are using 'cu' (or 'cutecom') sending (typing) a '?'
+ returns a full list of these
+ commands. The second level are configuration sub-commands accessed
+ using the 'c' command, for
+ instance typing 'c?' will give you this second level of commands
+ (all of which require the
+ letter 'c' to access). Please note that most configuration options
+ are stored only in DataFlash memory, and only TeleMetrum has this
+ memory to save the various values entered like the channel number
+ and your callsign when powered off. TeleDongle requires that you
+ set these each time you plug it in, which ao-view can help with.
+ </p><p>
+ Try setting these config ('c' or second level menu) values. A good
+ place to start is by setting your call sign. By default, the boards
+ use 'N0CALL' which is cute, but not exactly legal!
+ Spend a few minutes getting comfortable with the units, their
+ firmware, and 'cu' (or possibly 'cutecom').
+ For instance, try to send
+ (type) a 'c r 2' and verify the channel change by sending a 'c s'.
+ Verify you can connect and disconnect from the units while in your
+ terminal program by sending the escape-disconnect mentioned above.
+ </p><p>
+ Note that the 'reboot' command, which is very useful on TeleMetrum,
+ will likely just cause problems with the dongle. The *correct* way
+ to reset the dongle is just to unplug and re-plug it.
+ </p><p>
+ A fun thing to do at the launch site and something you can do while
+ learning how to use these units is to play with the rf-link access
+ of the TeleMetrum from the TeleDongle. Be aware that you *must* create
+ some physical separation between the devices, otherwise the link will
+ not function due to signal overload in the receivers in each device.
+ </p><p>
+ Now might be a good time to take a break and read the rest of this
+ manual, particularly about the two "modes" that the TeleMetrum
+ can be placed in and how the position of the TeleMetrum when booting
+ up will determine whether the unit is in "pad" or "idle" mode.
+ </p><p>
+ You can access a TeleMetrum in idle mode from the Teledongle's USB
+ connection using the rf link
+ by issuing a 'p' command to the TeleDongle. Practice connecting and
+ disconnecting ('~~' while using 'cu') from the TeleMetrum. If
+ you cannot escape out of the "p" command, (by using a '~~' when in
+ CU) then it is likely that your kernel has issues. Try a newer version.
+ </p><p>
+ Using this rf link allows you to configure the TeleMetrum, test
+ fire e-matches and igniters from the flight line, check pyro-match
+ continuity and so forth. You can leave the unit turned on while it
+ is in 'idle mode' and then place the
+ rocket vertically on the launch pad, walk away and then issue a
+ reboot command. The TeleMetrum will reboot and start sending data
+ having changed to the "pad" mode. If the TeleDongle is not receiving
+ this data, you can disconnect 'cu' from the Teledongle using the
+ procedures mentioned above and THEN connect to the TeleDongle from
+ inside 'ao-view'. If this doesn't work, disconnect from the
+ TeleDongle, unplug it, and try again after plugging it back in.
+ </p><p>
+ Eventually the GPS will find enough satellites, lock in on them,
+ and 'ao-view' will both auditorially announce and visually indicate
+ that GPS is ready.
+ Now you can launch knowing that you have a good data path and
+ good satellite lock for flight data and recovery. Remember
+ you MUST tell ao-view to connect to the TeleDongle explicitly in
+ order for ao-view to be able to receive data.
+ </p><p>
+ Both RDF (radio direction finding) tones from the TeleMetrum and
+ GPS trekking data are available and together are very useful in
+ locating the rocket once it has landed. (The last good GPS data
+ received before touch-down will be on the data screen of 'ao-view'.)
+ </p><p>
+ Once you have recovered the rocket you can download the eeprom
+ contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
+ either a USB cable or over the radio link using TeleDongle.
+ And by following the man page for 'ao-postflight' you can create
+ various data output reports, graphs, and even kml data to see the
+ flight trajectory in google-earth. (Moving the viewing angle making
+ sure to connect the yellow lines while in google-earth is the proper
+ technique.)
+ </p><p>
+ As for ao-view.... some things are in the menu but don't do anything
+ very useful. The developers have stopped working on ao-view to focus
+ on a new, cross-platform ground station program. So ao-view may or
+ may not be updated in the future. Mostly you just use
+ the Log and Device menus. It has a wonderful display of the incoming
+ flight data and I am sure you will enjoy what it has to say to you
+ once you enable the voice output!
+ </p><div class="section" title="FAQ"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2559795"></a>FAQ</h2></div></div></div><p>
+ The altimeter (TeleMetrum) seems to shut off when disconnected from the
+ computer. Make sure the battery is adequately charged. Remember the
+ unit will pull more power than the USB port can deliver before the
+ GPS enters "locked" mode. The battery charges best when TeleMetrum
+ is turned off.
+ </p><p>
+ It's impossible to stop the TeleDongle when it's in "p" mode, I have
+ to unplug the USB cable? Make sure you have tried to "escape out" of
+ this mode. If this doesn't work the reboot procedure for the
+ TeleDongle *is* to simply unplug it. 'cu' however will retain it's
+ outgoing buffer IF your "escape out" ('~~') does not work.
+ At this point using either 'ao-view' (or possibly
+ 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
+ communication.
+ </p><p>
+ The amber LED (on the TeleMetrum/altimeter) lights up when both
+ battery and USB are connected. Does this mean it's charging?
+ Yes, the yellow LED indicates the charging at the 'regular' rate.
+ If the led is out but the unit is still plugged into a USB port,
+ then the battery is being charged at a 'trickle' rate.
+ </p><p>
+ There are no "dit-dah-dah-dit" sound like the manual mentions?
+ That's the "pad" mode. Weak batteries might be the problem.
+ It is also possible that the unit is horizontal and the output
+ is instead a "dit-dit" meaning 'idle'.
+ </p><p>
+ It's unclear how to use 'ao-view' and other programs when 'cu'
+ is running. You cannot have more than one program connected to
+ the TeleDongle at one time without apparent data loss as the
+ incoming data will not make it to both programs intact.
+ Disconnect whatever programs aren't currently being used.
+ </p><p>
+ How do I save flight data?
+ Live telemetry is written to file(s) whenever 'ao-view' is connected
+ to the TeleDongle. The file area defaults to ~/altos
+ but is easily changed using the menus in 'ao-view'. The files that
+ are written end in '.telem'. The after-flight
+ data-dumped files will end in .eeprom and represent continuous data
+ unlike the rf-linked .telem files that are subject to the
+ turnarounds/data-packaging time slots in the half-duplex rf data path.
+ See the above instructions on what and how to save the eeprom stored
+ data after physically retrieving your TeleMetrum. Make sure to save
+ the on-board data after each flight, as the current firmware will
+ over-write any previous flight data during a new flight.
+ </p></div></div><div class="chapter" title="Chapter 3. Specifications"><div class="titlepage"><div><div><h2 class="title"><a name="id2546901"></a>Chapter 3. Specifications</h2></div></div></div><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>
+ Recording altimeter for model rocketry.
+ </p></li><li class="listitem"><p>
+ Supports dual deployment (can fire 2 ejection charges).
+ </p></li><li class="listitem"><p>
+ 70cm ham-band transceiver for telemetry downlink.
+ </p></li><li class="listitem"><p>
+ Barometric pressure sensor good to 45k feet MSL.
+ </p></li><li class="listitem"><p>
+ 1-axis high-g accelerometer for motor characterization, capable of
+ +/- 50g using default part.
+ </p></li><li class="listitem"><p>
+ On-board, integrated GPS receiver with 5hz update rate capability.
+ </p></li><li class="listitem"><p>
+ On-board 1 megabyte non-volatile memory for flight data storage.
+ </p></li><li class="listitem"><p>
+ USB interface for battery charging, configuration, and data recovery.
+ </p></li><li class="listitem"><p>
+ Fully integrated support for LiPo rechargeable batteries.
+ </p></li><li class="listitem"><p>
+ Uses LiPo to fire e-matches, support for optional separate pyro
+ battery if needed.
+ </p></li><li class="listitem"><p>
+ 2.75 x 1 inch board designed to fit inside 29mm airframe coupler tube.
+ </p></li></ul></div></div><div class="chapter" title="Chapter 4. Handling Precautions"><div class="titlepage"><div><div><h2 class="title"><a name="id2574755"></a>Chapter 4. Handling Precautions</h2></div></div></div><p>
+ TeleMetrum is a sophisticated electronic device. When handled gently and
+ properly installed in an airframe, it will deliver impressive results.
+ However, like all electronic devices, there are some precautions you
+ must take.
+ </p><p>
+ The Lithium Polymer rechargeable batteries used with TeleMetrum 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 airframe. We
+ often wrap them in suitable scraps of closed-cell packing foam before
+ strapping them down, for example.
+ </p><p>
+ The TeleMetrum barometric sensor is sensitive to sunlight. In normal
+ mounting situations, it and all of the other surface mount components
+ are "down" towards whatever the underlying mounting surface is, so
+ this is not normally a problem. Please consider this, though, when
+ designing an installation, for example, in a 29mm airframe with a
+ see-through plastic payload bay.
+ </p><p>
+ The TeleMetrum 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, but also by having a
+ suitable static vent to outside air.
+ </p><p>
+ As with all other rocketry electronics, TeleMetrum must be protected
+ from exposure to corrosive motor exhaust and ejection charge gasses.
+ </p></div><div class="chapter" title="Chapter 5. Hardware Overview"><div class="titlepage"><div><div><h2 class="title"><a name="id2547133"></a>Chapter 5. Hardware Overview</h2></div></div></div><p>
+ TeleMetrum is a 1 inch by 2.75 inch circuit board. It was designed to
+ fit inside coupler for 29mm airframe tubing, but using it in a tube that
+ small in diameter may require some creativity in mounting and wiring
+ to succeed! The default 1/4
+ wave UHF wire antenna attached to the center of the nose-cone end of
+ the board is about 7 inches long, and wiring for a power switch and
+ the e-matches for apogee and main ejection charges depart from the
+ fin can end of the board. Given all this, an ideal "simple" avionics
+ bay for TeleMetrum should have at least 10 inches of interior length.
+ </p><p>
+ A typical TeleMetrum installation using the on-board GPS antenna and
+ default wire UHF antenna involves attaching only a suitable
+ Lithium Polymer battery, a single pole switch for power on/off, and
+ two pairs of wires connecting e-matches for the apogee and main ejection
+ charges.
+ </p><p>
+ By default, we use the unregulated output of the LiPo 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, you can do so by adding
+ a second 2mm connector to position B2 on the board and cutting the
+ thick pcb trace connecting the LiPo battery to the pyro circuit between
+ the two silk screen marks on the surface mount side of the board shown
+ here [insert photo]
+ </p><p>
+ We offer two choices of pyro and power switch connector, or you can
+ choose neither and solder wires directly to the board. All three choices
+ are reasonable depending on the constraints of your airframe. Our
+ favorite option when there is sufficient room above the board is to use
+ the Tyco pin header with polarization and locking. If you choose this
+ option, you crimp individual wires for the power switch and e-matches
+ into a mating connector, and installing and removing the TeleMetrum
+ board from an airframe is as easy as plugging or unplugging two
+ connectors. If the airframe will not support this much height or if
+ you want to be able to directly attach e-match leads to the board, we
+ offer a screw terminal block. This is very similar to what most other
+ altimeter vendors provide and so may be the most familiar option.
+ You'll need a very small straight blade screwdriver to connect
+ and disconnect the board in this case, such as you might find in a
+ jeweler's screwdriver set. Finally, you can forego both options and
+ solder wires directly to the board, which may be the best choice for
+ minimum diameter and/or minimum mass designs.
+ </p><p>
+ For most airframes, the integrated GPS antenna and wire UHF antenna are
+ a great combination. However, if you are installing in a carbon-fiber
+ electronics bay which is opaque to RF signals, you may need to use
+ off-board external antennas instead. In this case, you can order
+ TeleMetrum with an SMA connector for the UHF antenna connection, and
+ you can unplug the integrated GPS antenna and select an appropriate
+ off-board GPS antenna with cable terminating in a U.FL connector.
+ </p></div><div class="chapter" title="Chapter 6. Operation"><div class="titlepage"><div><div><h2 class="title"><a name="id2552998"></a>Chapter 6. Operation</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id2556146">Firmware Modes </a></span></dt><dt><span class="section"><a href="#id2557858">GPS </a></span></dt><dt><span class="section"><a href="#id2572262">Ground Testing </a></span></dt><dt><span class="section"><a href="#id2572259">Radio Link </a></span></dt><dt><span class="section"><a href="#id2542980">Configurable Parameters</a></span></dt><dd><dl><dt><span class="section"><a href="#id2563251">Radio Channel</a></span></dt><dt><span class="section"><a href="#id2554165">Apogee Delay</a></span></dt><dt><span class="section"><a href="#id2571971">Main Deployment Altitude</a></span></dt></dl></dd><dt><span class="section"><a href="#id2550600">Calibration</a></span></dt><dd><dl><dt><span class="section"><a href="#id2574322">Radio Frequency</a></span></dt><dt><span class="section"><a href="#id2564433">Accelerometer</a></span></dt></dl></dd></dl></div><div class="section" title="Firmware Modes"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2556146"></a>Firmware Modes </h2></div></div></div><p>
+ The AltOS firmware build for TeleMetrum has two fundamental modes,
+ "idle" and "flight". Which of these modes the firmware operates in
+ is determined by the orientation of the rocket (well, actually the
+ board, of course...) at the time power is switched on. If the rocket
+ is "nose up", then TeleMetrum assumes it's on a rail or rod being
+ prepared for launch, so the firmware chooses flight mode. However,
+ if the rocket is more or less horizontal, the firmware instead enters
+ idle mode.
+ </p><p>
+ At power on, you will hear three beeps
+ ("S" in Morse code for startup) and then a pause while
+ TeleMetrum completes initialization and self tests, and decides which
+ mode to enter next.
+ </p><p>
+ In flight or "pad" mode, TeleMetrum turns on the GPS system,
+ engages the flight
+ state machine, goes into transmit-only mode on the RF link sending
+ telemetry, and waits for launch to be detected. Flight mode is
+ indicated by an audible "di-dah-dah-dit" ("P" for pad) on the
+ beeper, followed by
+ beeps indicating the state of the pyrotechnic igniter continuity.
+ One beep indicates apogee continuity, two beeps indicate
+ main continuity, three beeps indicate both apogee and main continuity,
+ and one longer "brap" sound indicates no continuity. For a dual
+ deploy flight, make sure you're getting three beeps before launching!
+ For apogee-only or motor eject flights, do what makes sense.
+ </p><p>
+ In idle mode, you will hear an audible "di-dit" ("I" for idle), and
+ the normal flight state machine is disengaged, thus
+ no ejection charges will fire. TeleMetrum also listens on the RF
+ link when in idle mode for packet mode requests sent from TeleDongle.
+ Commands can be issued to a TeleMetrum in idle mode over either
+ USB or the RF link equivalently.
+ Idle mode is useful for configuring TeleMetrum, for extracting data
+ from the on-board storage chip after flight, and for ground testing
+ pyro charges.
+ </p><p>
+ One "neat trick" of particular value when TeleMetrum is used with very
+ large airframes, 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 airframe to launch position, use a TeleDongle to open
+ a packet connection, and issue a 'reset' command which will cause
+ TeleMetrum to reboot, realize it's now nose-up, and thus choose
+ 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!
+ </p></div><div class="section" title="GPS"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2557858"></a>GPS </h2></div></div></div><p>
+ TeleMetrum includes a complete GPS receiver. See a later section for
+ a brief explanation of how GPS works that will help you understand
+ the information in the telemetry stream. The bottom line is that
+ the TeleMetrum GPS receiver needs to lock onto at least four
+ satellites to obtain a solid 3 dimensional position fix and know
+ what time it is!
+ </p><p>
+ TeleMetrum provides backup power to the GPS chip any time a LiPo
+ battery is connected. This allows the receiver to "warm start" on
+ the launch rail much faster than if every power-on were a "cold start"
+ for the GPS receiver. In typical operations, powering up TeleMetrum
+ on the flight line in idle mode while performing final airframe
+ 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.
+ </p></div><div class="section" title="Ground Testing"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2572262"></a>Ground Testing </h2></div></div></div><p>
+ An important aspect of preparing a rocket using electronic deployment
+ for flight is ground testing the recovery system. Thanks
+ to the bi-directional RF link central to the Altus Metrum system,
+ this can be accomplished in a TeleMetrum-equipped rocket without as
+ much work as you may be accustomed to with other systems. It can
+ even be fun!
+ </p><p>
+ Just prep the rocket for flight, then power up TeleMetrum while the
+ airframe is horizontal. 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. Then, establish an
+ RF packet connection from a TeleDongle-equipped computer using the
+ P command from a safe distance. You can now command TeleMetrum to
+ fire the apogee or main charges to complete your testing.
+ </p><p>
+ In order to reduce the chance of accidental firing of pyrotechnic
+ charges, the command to fire a charge is intentionally somewhat
+ difficult to type, and the built-in help is slightly cryptic to
+ prevent accidental echoing of characters from the help text back at
+ the board from firing a charge. The command to fire the apogee
+ drogue charge is 'i DoIt drogue' and the command to fire the main
+ charge is 'i DoIt main'.
+ </p></div><div class="section" title="Radio Link"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2572259"></a>Radio Link </h2></div></div></div><p>
+ The chip our boards are based on incorporates an RF transceiver, but
+ it's not a full duplex system... each end can only be transmitting or
+ receiving at any given moment. So we had to decide how to manage the
+ link.
+ </p><p>
+ By design, TeleMetrum firmware listens for an RF connection when
+ it's in "idle mode" (turned on while the rocket is horizontal), which
+ allows us to use the RF link to configure the rocket, do things like
+ ejection tests, and extract data after a flight without having to
+ crack open the airframe. However, when the board is in "flight
+ mode" (turned on when the rocket is vertical) the TeleMetrum 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 and out over
+ the RF link in case the rocket crashes and we aren't able to extract
+ data later...
+ </p><p>
+ We don't use a 'normal packet radio' mode because they're just too
+ inefficient. The GFSK modulation we use is just FSK with the
+ baseband pulses passed through a
+ Gaussian filter before they go into the modulator to limit the
+ transmitted bandwidth. When combined with the hardware forward error
+ correction support in the cc1111 chip, this allows us to have a very
+ robust 38.4 kilobit data link with only 10 milliwatts of transmit power,
+ a whip antenna in the rocket, and a hand-held Yagi on the ground. We've
+ had flights to above 21k feet AGL with good reception, and calculations
+ suggest we should be good to well over 40k feet AGL with a 5-element yagi on
+ the ground. We hope to fly boards to higher altitudes soon, and would
+ of course appreciate customer feedback on performance in higher
+ altitude flights!
+ </p></div><div class="section" title="Configurable Parameters"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2542980"></a>Configurable Parameters</h2></div></div></div><p>
+ Configuring a TeleMetrum board for flight is very simple. Because we
+ have both acceleration and pressure sensors, there is no need to set
+ a "mach delay", for example. The few configurable parameters can all
+ be set using a simple terminal program over the USB port or RF link
+ via TeleDongle.
+ </p><div class="section" title="Radio Channel"><div class="titlepage"><div><div><h3 class="title"><a name="id2563251"></a>Radio Channel</h3></div></div></div><p>
+ Our firmware supports 10 channels. The default channel 0 corresponds
+ to a center frequency of 434.550 Mhz, and channels are spaced every
+ 100 khz. Thus, channel 1 is 434.650 Mhz, and channel 9 is 435.550 Mhz.
+ At any given launch, we highly recommend coordinating who will use
+ each channel and when to avoid interference. And of course, both
+ TeleMetrum and TeleDongle must be configured to the same channel to
+ successfully communicate with each other.
+ </p><p>
+ To set the radio channel, use the 'c r' command, like 'c r 3' to set
+ channel 3.
+ As with all 'c' sub-commands, follow this with a 'c w' to write the
+ change to the parameter block in the on-board DataFlash chip on
+ your TeleMetrum board if you want the change to stay in place across reboots.
+ </p></div><div class="section" title="Apogee Delay"><div class="titlepage"><div><div><h3 class="title"><a name="id2554165"></a>Apogee Delay</h3></div></div></div><p>
+ Apogee delay is the number of seconds after TeleMetrum detects flight
+ apogee that the drogue charge should be fired. In most cases, this
+ should be left at the default of 0. However, if you are flying
+ redundant electronics such as for an L3 certification, you may wish
+ to set one of your altimeters to a positive delay so that both
+ primary and backup pyrotechnic charges do not fire simultaneously.
+ </p><p>
+ To set the apogee delay, use the [FIXME] command.
+ As with all 'c' sub-commands, follow this with a 'c w' to write the
+ change to the parameter block in the on-board DataFlash chip.
+ </p><p>
+ Please note that the TeleMetrum apogee detection algorithm always
+ fires a fraction of a second *after* apogee. If you are also flying
+ an altimeter like the PerfectFlite MAWD, which only supports selecting
+ 0 or 1 seconds of apogee delay, you may wish to set the MAWD to 0
+ seconds delay and set the TeleMetrum to fire your backup 2 or 3
+ seconds later to avoid any chance of both charges firing
+ simultaneously. We've flown several airframes this way quite happily,
+ including Keith's successful L3 cert.
+ </p></div><div class="section" title="Main Deployment Altitude"><div class="titlepage"><div><div><h3 class="title"><a name="id2571971"></a>Main Deployment Altitude</h3></div></div></div><p>
+ By default, TeleMetrum will fire the main deployment charge at an
+ elevation of 250 meters (about 820 feet) above ground. We think this
+ is a good elevation for most airframes, but feel free to change this
+ to suit. In particular, if you are flying two altimeters, you may
+ wish to set the
+ deployment elevation for the backup altimeter to be something lower
+ than the primary so that both pyrotechnic charges don't fire
+ simultaneously.
+ </p><p>
+ To set the main deployment altitude, use the [FIXME] command.
+ As with all 'c' sub-commands, follow this with a 'c w' to write the
+ change to the parameter block in the on-board DataFlash chip.
+ </p></div></div><div class="section" title="Calibration"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2550600"></a>Calibration</h2></div></div></div><p>
+ There are only two calibrations required for a TeleMetrum board, and
+ only one for TeleDongle.
+ </p><div class="section" title="Radio Frequency"><div class="titlepage"><div><div><h3 class="title"><a name="id2574322"></a>Radio Frequency</h3></div></div></div><p>
+ The radio frequency is synthesized from a clock based on the 48 Mhz
+ crystal on the board. The actual frequency of this oscillator must be
+ measured to generate a calibration constant. While our GFSK modulation
+ bandwidth is wide enough to allow boards to communicate even when
+ their oscillators are not on exactly the same frequency, performance
+ is best when they are closely matched.
+ Radio frequency calibration requires a calibrated frequency counter.
+ Fortunately, once set, the variation in frequency due to aging and
+ temperature changes is small enough that re-calibration by customers
+ should generally not be required.
+ </p><p>
+ To calibrate the radio frequency, connect the UHF antenna port to a
+ frequency counter, set the board to channel 0, and use the 'C'
+ command to generate a CW carrier. Wait for the transmitter temperature
+ to stabilize and the frequency to settle down.
+ Then, divide 434.550 Mhz by the
+ measured frequency and multiply by the current radio cal value show
+ in the 'c s' command. For an unprogrammed board, the default value
+ is 1186611. Take the resulting integer and program it using the 'c f'
+ command. Testing with the 'C' command again should show a carrier
+ within a few tens of Hertz of the intended frequency.
+ As with all 'c' sub-commands, follow this with a 'c w' to write the
+ change to the parameter block in the on-board DataFlash chip.
+ </p></div><div class="section" title="Accelerometer"><div class="titlepage"><div><div><h3 class="title"><a name="id2564433"></a>Accelerometer</h3></div></div></div><p>
+ The accelerometer we use has its own 5 volt power supply and
+ the output must be passed through a resistive voltage divider to match
+ the input of our 3.3 volt ADC. This means that unlike the barometric
+ sensor, the output of the acceleration sensor is not ratiometric to
+ the ADC converter, and calibration is required. We also support the
+ use of any of several accelerometers from a Freescale family that
+ includes at least +/- 40g, 50g, 100g, and 200g parts. Using gravity,
+ a simple 2-point calibration yields acceptable results capturing both
+ the different sensitivities and ranges of the different accelerometer
+ parts and any variation in power supply voltages or resistor values
+ in the divider network.
+ </p><p>
+ To calibrate the acceleration sensor, use the 'c a 0' command. You
+ will be prompted to orient the board vertically with the UHF antenna
+ up and press a key, then to orient the board vertically with the
+ UHF antenna down and press a key.
+ As with all 'c' sub-commands, follow this with a 'c w' to write the
+ change to the parameter block in the on-board DataFlash chip.
+ </p><p>
+ The +1g and -1g calibration points are included in each telemetry
+ frame and are part of the header extracted by ao-dumplog after flight.
+ Note that we always store and return raw ADC samples for each
+ sensor... nothing is permanently "lost" or "damaged" if the
+ calibration is poor.
+ </p></div></div></div><div class="chapter" title="Chapter 7. Updating Device Firmware"><div class="titlepage"><div><div><h2 class="title"><a name="id2554553"></a>Chapter 7. Updating Device Firmware</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id2569887">Updating TeleMetrum Firmware</a></span></dt><dt><span class="section"><a href="#id2552683">Updating TeleDongle Firmware</a></span></dt></dl></div><p>
+ The big conceptual thing to realize is that you have to use a
+ TeleDongle as a programmer to update a TeleMetrum, and vice versa.
+ Due to limited memory resources in the cc1111, we don't support
+ programming either unit directly over USB.
+ </p><p>
+ 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/.
+ </p><p>
+ We recommend updating TeleMetrum first, before updating TeleDongle.
+ </p><div class="section" title="Updating TeleMetrum Firmware"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2569887"></a>Updating TeleMetrum Firmware</h2></div></div></div><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
+ Find the 'programming cable' that you got as part of the starter
+ kit, that has a red 8-pin MicroMaTch connector on one end and a
+ red 4-pin MicroMaTch connector on the other end.
+ </li><li class="listitem">
+ Take the 2 screws out of the TeleDongle case to get access
+ to the circuit board.
+ </li><li class="listitem">
+ Plug the 8-pin end of the programming cable to the
+ matching connector on the TeleDongle, and the 4-pin end to the
+ matching connector on the TeleMetrum.
+ </li><li class="listitem">
+ Attach a battery to the TeleMetrum board.
+ </li><li class="listitem">
+ Plug the TeleDongle into your computer's USB port, and power
+ up the TeleMetrum.
+ </li><li class="listitem">
+ Run AltosUI, and select 'Flash Image' from the File menu.
+ </li><li class="listitem">
+ Pick the TeleDongle device from the list, identifying it as the
+ programming device.
+ </li><li class="listitem">
+ Select the image you want put on the TeleMetrum, which should have a
+ name in the form telemetrum-v1.0-0.7.1.ihx. It should be visible
+ in the default directory, if not you may have to poke around
+ your system to find it.
+ </li><li class="listitem">
+ Make sure the configuration parameters are reasonable
+ looking. If the serial number and/or RF configuration
+ values aren't right, you'll need to change them.
+ </li><li class="listitem">
+ Hit the 'OK' button and the software should proceed to flash
+ the TeleMetrum with new firmware, showing a progress bar.
+ </li><li class="listitem">
+ Confirm that the TeleMetrum board seems to have updated ok, which you
+ can do by plugging in to it over USB and using a terminal program
+ to connect to the board and issue the 'v' command to check
+ the version, etc.
+ </li><li class="listitem">
+ If something goes wrong, give it another try.
+ </li></ol></div></div><div class="section" title="Updating TeleDongle Firmware"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2552683"></a>Updating TeleDongle Firmware</h2></div></div></div><p>
+ Updating TeleDongle's firmware is just like updating TeleMetrum
+ firmware, but you switch which board is the programmer and which
+ is the programming target.
+ </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
+ Find the 'programming cable' that you got as part of the starter
+ kit, that has a red 8-pin MicroMaTch connector on one end and a
+ red 4-pin MicroMaTch connector on the other end.
+ </li><li class="listitem">
+ Find the USB cable that you got as part of the starter kit, and
+ plug the "mini" end in to the mating connector on TeleMetrum.
+ </li><li class="listitem">
+ Take the 2 screws out of the TeleDongle case to get access
+ to the circuit board.
+ </li><li class="listitem">
+ Plug the 8-pin end of the programming cable to the (latching)
+ matching connector on the TeleMetrum, and the 4-pin end to the
+ matching connector on the TeleDongle.
+ </li><li class="listitem">
+ Attach a battery to the TeleMetrum board.
+ </li><li class="listitem">
+ Plug both TeleMetrum and TeleDongle into your computer's USB
+ ports, and power up the TeleMetrum.
+ </li><li class="listitem">
+ Run AltosUI, and select 'Flash Image' from the File menu.
+ </li><li class="listitem">
+ Pick the TeleMongle device from the list, identifying it as the
+ programming device.
+ </li><li class="listitem">
+ Select the image you want put on the TeleDongle, which should have a
+ name in the form teledongle-v0.2-0.7.1.ihx. It should be visible
+ in the default directory, if not you may have to poke around
+ your system to find it.
+ </li><li class="listitem">
+ Make sure the configuration parameters are reasonable
+ looking. If the serial number and/or RF configuration
+ values aren't right, you'll need to change them. The TeleDongle
+ serial number is on the "bottom" of the circuit board, and can
+ usually be read through the translucent blue plastic case without
+ needing to remove the board from the case.
+ </li><li class="listitem">
+ Hit the 'OK' button and the software should proceed to flash
+ the TeleDongle with new firmware, showing a progress bar.
+ </li><li class="listitem">
+ Confirm that the TeleDongle board seems to have updated ok, which you
+ can do by plugging in to it over USB and using a terminal program
+ to connect to the board and issue the 'v' command to check
+ the version, etc. Once you're happy, remove the programming cable
+ and put the cover back on the TeleDongle.
+ </li><li class="listitem">
+ If something goes wrong, give it another try.
+ </li></ol></div><p>
+ 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.
+ </p></div></div><div class="chapter" title="Chapter 8. Using Altus Metrum Products"><div class="titlepage"><div><div><h2 class="title"><a name="id2539483"></a>Chapter 8. Using Altus Metrum Products</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id2558109">Being Legal</a></span></dt><dd><dl><dt><span class="section"><a href="#id2554650">In the Rocket</a></span></dt><dt><span class="section"><a href="#id2572268">On the Ground</a></span></dt><dt><span class="section"><a href="#id2569008">Data Analysis</a></span></dt><dt><span class="section"><a href="#id2563568">Future Plans</a></span></dt></dl></dd><dt><span class="section"><a href="#id2567979">
+ How GPS Works
+ </a></span></dt></dl></div><div class="section" title="Being Legal"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2558109"></a>Being Legal</h2></div></div></div><p>
+ First off, in the US, you need an [amateur radio license](../Radio) or
+ other authorization to legally operate the radio transmitters that are part
+ of our products.
+ </p><div class="section" title="In the Rocket"><div class="titlepage"><div><div><h3 class="title"><a name="id2554650"></a>In the Rocket</h3></div></div></div><p>
+ In the rocket itself, you just need a [TeleMetrum](../TeleMetrum) board and
+ a LiPo rechargeable battery. An 860mAh battery weighs less than a 9V
+ alkaline battery, and will run a [TeleMetrum](../TeleMetrum) for hours.
+ </p><p>
+ By default, we ship TeleMetrum with a simple wire antenna. If your
+ electronics bay or the airframe it resides within is made of carbon fiber,
+ which is opaque to RF signals, you may choose to have an SMA connector
+ installed so that you can run a coaxial cable to an antenna mounted
+ elsewhere in the rocket.
+ </p></div><div class="section" title="On the Ground"><div class="titlepage"><div><div><h3 class="title"><a name="id2572268"></a>On the Ground</h3></div></div></div><p>
+ To receive the data stream from the rocket, you need an antenna and short
+ feedline connected to one of our [TeleDongle](../TeleDongle) units. The
+ TeleDongle in turn plugs directly into the USB port on a notebook
+ computer. Because TeleDongle looks like a simple serial port, your computer
+ does not require special device drivers... just plug it in.
+ </p><p>
+ Right now, all of our application software is written for Linux. However,
+ because we understand that many people run Windows or MacOS, we are working
+ on a new ground station program written in Java that should work on all
+ operating systems.
+ </p><p>
+ After the flight, you can use the RF link to extract the more detailed data
+ logged in the rocket, or you can use a mini USB cable to plug into the
+ TeleMetrum board directly. Pulling out the data without having to open up
+ the rocket is pretty cool! A USB cable is also how you charge the LiPo
+ 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.
+ </p><p>
+ If your rocket lands out of sight, you may enjoy having a hand-held GPS
+ receiver, so that you can put in a waypoint for the last reported rocket
+ position before touch-down. This makes looking for your rocket a lot like
+ Geo-Cacheing... just go to the waypoint and look around starting from there.
+ </p><p>
+ You may also enjoy having a ham radio "HT" that covers the 70cm band... you
+ can use that with your antenna to direction-find the rocket on the ground
+ the same way you can use a Walston or Beeline tracker. This can be handy
+ if the rocket is hiding in sage brush or a tree, or if the last GPS position
+ doesn't get you close enough because the rocket dropped into a canyon, or
+ the wind is blowing it across a dry lake bed, or something like that... Keith
+ and Bdale both currently own and use the Yaesu VX-7R at launches.
+ </p><p>
+ So, to recap, on the ground the hardware you'll need includes:
+ </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
+ an antenna and feedline
+ </li><li class="listitem">
+ a TeleDongle
+ </li><li class="listitem">
+ a notebook computer
+ </li><li class="listitem">
+ optionally, a handheld GPS receiver
+ </li><li class="listitem">
+ optionally, an HT or receiver covering 435 Mhz
+ </li></ol></div><p>
+ </p><p>
+ The best hand-held commercial directional antennas we've found for radio
+ direction finding rockets are from
+ <a class="ulink" href="http://www.arrowantennas.com/" target="_top">
+ Arrow Antennas.
+ </a>
+ The 440-3 and 440-5 are both good choices for finding a
+ TeleMetrum-equipped rocket when used with a suitable 70cm HT.
+ </p></div><div class="section" title="Data Analysis"><div class="titlepage"><div><div><h3 class="title"><a name="id2569008"></a>Data Analysis</h3></div></div></div><p>
+ Our software makes it easy to log the data from each flight, both the
+ telemetry received over the RF link during the flight itself, and the more
+ complete data log recorded in the DataFlash memory on the TeleMetrum
+ board. Once this data is on your computer, our postflight 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 data file
+ useable with Google Maps and Google Earth for visualizing the flight path
+ in two or three dimensions!
+ </p><p>
+ 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.
+ </p></div><div class="section" title="Future Plans"><div class="titlepage"><div><div><h3 class="title"><a name="id2563568"></a>Future Plans</h3></div></div></div><p>
+ In the future, we intend to offer "companion boards" for the rocket that will
+ plug in to TeleMetrum to collect additional data, provide more pyro channels,
+ and so forth. A reference design for a companion board will be documented
+ soon, and will be compatible with open source Arduino programming tools.
+ </p><p>
+ We are also working on the design of a hand-held ground terminal that will
+ allow monitoring the rocket's status, collecting data during flight, and
+ logging data after flight without the need for a notebook computer on the
+ flight line. Particularly since it is so difficult to read most notebook
+ screens in direct sunlight, we think this will be a great thing to have.
+ </p><p>
+ 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...
+ </p></div></div><div class="section" title="How GPS Works"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2567979"></a>
+ How GPS Works
+ </h2></div></div></div><p>
+ Placeholder.
+ </p></div></div></div></body></html>
## Available Versions ##
+There is a single manual for all Altus Metrum products, which is available
+in [html](doc/altusmetrum.html) and [pdf](doc/altusmetrum.pdf) formats.
+
[[!inline pages="./releases/* and !*/Discussion and !*.bz2 and !*.zip and !*.exe" show="10" rss="no" raw="yes" ]]
The latest source is always available from [git.gag.com](http://git.gag.com)
+++ /dev/null
-<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>TeleMetrum</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="book" title="TeleMetrum"><div class="titlepage"><div><div><h1 class="title"><a name="id2276207"></a>TeleMetrum</h1></div><div><h2 class="subtitle">Owner's Manual for the TeleMetrum System</h2></div><div><div class="author"><h3 class="author"><span class="firstname">Bdale</span> <span class="surname">Garbee</span></h3></div></div><div><div class="author"><h3 class="author"><span class="firstname">Keith</span> <span class="surname">Packard</span></h3></div></div><div><p class="copyright">Copyright © 2010 Bdale Garbee and Keith Packard</p></div><div><div class="legalnotice" title="Legal Notice"><a name="id2559812"></a><p>
- This document is released under the terms of the
- <a class="ulink" href="http://creativecommons.org/licenses/by-sa/3.0/" target="_top">
- Creative Commons ShareAlike 3.0
- </a>
- license.
- </p></div></div><div><div class="revhistory"><table border="1" width="100%" summary="Revision history"><tr><th align="left" valign="top" colspan="2"><b>Revision History</b></th></tr><tr><td align="left">Revision 0.3</td><td align="left">12 November 2010</td></tr><tr><td align="left" colspan="2">
- Add instructions for re-flashing devices using AltosUI
- </td></tr><tr><td align="left">Revision 0.2</td><td align="left">18 July 2010</td></tr><tr><td align="left" colspan="2">Significant update</td></tr><tr><td align="left">Revision 0.1</td><td align="left">30 March 2010</td></tr><tr><td align="left" colspan="2">Initial content</td></tr></table></div></div></div><hr></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="chapter"><a href="#id2555013">1. Introduction and Overview</a></span></dt><dt><span class="chapter"><a href="#id2540100">2. Getting Started</a></span></dt><dd><dl><dt><span class="section"><a href="#id2559795">FAQ</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id2546901">3. Specifications</a></span></dt><dt><span class="chapter"><a href="#id2574755">4. Handling Precautions</a></span></dt><dt><span class="chapter"><a href="#id2547133">5. Hardware Overview</a></span></dt><dt><span class="chapter"><a href="#id2552998">6. Operation</a></span></dt><dd><dl><dt><span class="section"><a href="#id2556146">Firmware Modes </a></span></dt><dt><span class="section"><a href="#id2557858">GPS </a></span></dt><dt><span class="section"><a href="#id2572262">Ground Testing </a></span></dt><dt><span class="section"><a href="#id2572259">Radio Link </a></span></dt><dt><span class="section"><a href="#id2542980">Configurable Parameters</a></span></dt><dd><dl><dt><span class="section"><a href="#id2563251">Radio Channel</a></span></dt><dt><span class="section"><a href="#id2554165">Apogee Delay</a></span></dt><dt><span class="section"><a href="#id2571971">Main Deployment Altitude</a></span></dt></dl></dd><dt><span class="section"><a href="#id2550600">Calibration</a></span></dt><dd><dl><dt><span class="section"><a href="#id2574322">Radio Frequency</a></span></dt><dt><span class="section"><a href="#id2564433">Accelerometer</a></span></dt></dl></dd></dl></dd><dt><span class="chapter"><a href="#id2554553">7. Updating Device Firmware</a></span></dt><dd><dl><dt><span class="section"><a href="#id2569887">Updating TeleMetrum Firmware</a></span></dt><dt><span class="section"><a href="#id2552683">Updating TeleDongle Firmware</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id2539483">8. Using Altus Metrum Products</a></span></dt><dd><dl><dt><span class="section"><a href="#id2558109">Being Legal</a></span></dt><dd><dl><dt><span class="section"><a href="#id2554650">In the Rocket</a></span></dt><dt><span class="section"><a href="#id2572268">On the Ground</a></span></dt><dt><span class="section"><a href="#id2569008">Data Analysis</a></span></dt><dt><span class="section"><a href="#id2563568">Future Plans</a></span></dt></dl></dd><dt><span class="section"><a href="#id2567979">
- How GPS Works
- </a></span></dt></dl></dd></dl></div><div class="chapter" title="Chapter 1. Introduction and Overview"><div class="titlepage"><div><div><h2 class="title"><a name="id2555013"></a>Chapter 1. Introduction and Overview</h2></div></div></div><p>
- 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!
- </p><p>
- The focal point of our community is 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.
- </p><p>
- Complementing TeleMetrum is TeleDongle, a USB to RF interface for
- communicating with TeleMetrum. 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.
- </p><p>
- 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.
- </p></div><div class="chapter" title="Chapter 2. Getting Started"><div class="titlepage"><div><div><h2 class="title"><a name="id2540100"></a>Chapter 2. Getting Started</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id2559795">FAQ</a></span></dt></dl></div><p>
- This chapter began as "The Mere-Mortals Quick Start/Usage Guide to
- the Altus Metrum Starter Kit" by Bob Finch, W9YA, NAR 12965, TRA 12350,
- w9ya@amsat.org. Bob was one of our first customers for a production
- TeleMetrum, and the enthusiasm that led to his contribution of this
- section is immensely gratifying and highy appreciated!
- </p><p>
- The first thing to do after you check the inventory of parts in your
- "starter kit" is to charge the battery by plugging it into the
- corresponding socket of the TeleMetrum and then using the USB A to B
- cable to plug the Telemetrum into your computer's USB socket. The
- TeleMetrum circuitry will charge the battery whenever it is plugged
- into the usb socket. The TeleMetrum's on-off switch does NOT control
- the charging circuitry. When the GPS chip is initially searching for
- satellites, the unit will pull more current than it can pull from the
- usb port, so the battery must be plugged in order to get a good
- 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.
- </p><p>
- The other active device in the starter kit is the half-duplex TeleDongle
- rf link. If you plug it in to your computer it should "just work",
- showing up as a serial port device. If you are using Linux and are
- having problems, try moving to a fresher kernel (2.6.33 or newer), as
- there were some ugly USB serial driver bugs in earlier versions.
- </p><p>
- Next you should obtain and install the AltOS utilities. The first
- generation sofware was written for Linux only. New software is coming
- soon that will also run on Windows and Mac. For now, we'll concentrate
- on Linux. If you are using Debian, an 'altos' package already exists,
- see http://altusmetrum.org/AltOS for details on how to install it.
- User-contributed directions for building packages on ArchLinux may be
- found in the contrib/arch-linux directory as PKGBUILD files.
- Between the debian/rules file and the PKGBUILD files in
- contrib, you should find enough information to learn how to build the
- software for any other version of Linux.
- </p><p>
- When you have successfully installed the software suite (either from
- compiled source code or as the pre-built Debian package) you will
- have 10 or so executable programs all of which have names beginning
- with 'ao-'.
- ('ao-view' is the lone GUI-based program, the rest are command-line
- oriented.) You will also have man pages, that give you basic info
- on each program.
- You will also get this documentation in two file types in the doc/
- directory, telemetrum-doc.pdf and telemetrum-doc.html.
- Finally you will have a couple control files that allow the ao-view
- GUI-based program to appear in your menu of programs (under
- the 'Internet' category).
- </p><p>
- Both Telemetrum and TeleDongle can be directly communicated
- with using USB ports. The first thing you should try after getting
- both units plugged into to your computer's usb port(s) is to run
- 'ao-list' from a terminal-window to see what port-device-name each
- device has been assigned by the operating system.
- You will need this information to access the devices via their
- respective on-board firmware and data using other command line
- programs in the AltOS software suite.
- </p><p>
- To access the device's firmware for configuration you need a terminal
- program such as you would use to talk to a modem. The software
- authors prefer using the program 'cu' which comes from the UUCP package
- on most Unix-like systems such as Linux. An example command line for
- cu might be 'cu -l /dev/ttyACM0', substituting the correct number
- indicated from running the
- ao-list program. Another reasonable terminal program for Linux is
- 'cutecom'. The default 'escape'
- character used by CU (i.e. the character you use to
- issue commands to cu itself instead of sending the command as input
- to the connected device) is a '~'. You will need this for use in
- only two different ways during normal operations. First is to exit
- the program by sending a '~.' which is called a 'escape-disconnect'
- and allows you to close-out from 'cu'. The
- second use will be outlined later.
- </p><p>
- Both TeleMetrum and TeleDongle share the concept of a two level
- command set in their firmware.
- The first layer has several single letter commands. Once
- you are using 'cu' (or 'cutecom') sending (typing) a '?'
- returns a full list of these
- commands. The second level are configuration sub-commands accessed
- using the 'c' command, for
- instance typing 'c?' will give you this second level of commands
- (all of which require the
- letter 'c' to access). Please note that most configuration options
- are stored only in DataFlash memory, and only TeleMetrum has this
- memory to save the various values entered like the channel number
- and your callsign when powered off. TeleDongle requires that you
- set these each time you plug it in, which ao-view can help with.
- </p><p>
- Try setting these config ('c' or second level menu) values. A good
- place to start is by setting your call sign. By default, the boards
- use 'N0CALL' which is cute, but not exactly legal!
- Spend a few minutes getting comfortable with the units, their
- firmware, and 'cu' (or possibly 'cutecom').
- For instance, try to send
- (type) a 'c r 2' and verify the channel change by sending a 'c s'.
- Verify you can connect and disconnect from the units while in your
- terminal program by sending the escape-disconnect mentioned above.
- </p><p>
- Note that the 'reboot' command, which is very useful on TeleMetrum,
- will likely just cause problems with the dongle. The *correct* way
- to reset the dongle is just to unplug and re-plug it.
- </p><p>
- A fun thing to do at the launch site and something you can do while
- learning how to use these units is to play with the rf-link access
- of the TeleMetrum from the TeleDongle. Be aware that you *must* create
- some physical separation between the devices, otherwise the link will
- not function due to signal overload in the receivers in each device.
- </p><p>
- Now might be a good time to take a break and read the rest of this
- manual, particularly about the two "modes" that the TeleMetrum
- can be placed in and how the position of the TeleMetrum when booting
- up will determine whether the unit is in "pad" or "idle" mode.
- </p><p>
- You can access a TeleMetrum in idle mode from the Teledongle's USB
- connection using the rf link
- by issuing a 'p' command to the TeleDongle. Practice connecting and
- disconnecting ('~~' while using 'cu') from the TeleMetrum. If
- you cannot escape out of the "p" command, (by using a '~~' when in
- CU) then it is likely that your kernel has issues. Try a newer version.
- </p><p>
- Using this rf link allows you to configure the TeleMetrum, test
- fire e-matches and igniters from the flight line, check pyro-match
- continuity and so forth. You can leave the unit turned on while it
- is in 'idle mode' and then place the
- rocket vertically on the launch pad, walk away and then issue a
- reboot command. The TeleMetrum will reboot and start sending data
- having changed to the "pad" mode. If the TeleDongle is not receiving
- this data, you can disconnect 'cu' from the Teledongle using the
- procedures mentioned above and THEN connect to the TeleDongle from
- inside 'ao-view'. If this doesn't work, disconnect from the
- TeleDongle, unplug it, and try again after plugging it back in.
- </p><p>
- Eventually the GPS will find enough satellites, lock in on them,
- and 'ao-view' will both auditorially announce and visually indicate
- that GPS is ready.
- Now you can launch knowing that you have a good data path and
- good satellite lock for flight data and recovery. Remember
- you MUST tell ao-view to connect to the TeleDongle explicitly in
- order for ao-view to be able to receive data.
- </p><p>
- Both RDF (radio direction finding) tones from the TeleMetrum and
- GPS trekking data are available and together are very useful in
- locating the rocket once it has landed. (The last good GPS data
- received before touch-down will be on the data screen of 'ao-view'.)
- </p><p>
- Once you have recovered the rocket you can download the eeprom
- contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
- either a USB cable or over the radio link using TeleDongle.
- And by following the man page for 'ao-postflight' you can create
- various data output reports, graphs, and even kml data to see the
- flight trajectory in google-earth. (Moving the viewing angle making
- sure to connect the yellow lines while in google-earth is the proper
- technique.)
- </p><p>
- As for ao-view.... some things are in the menu but don't do anything
- very useful. The developers have stopped working on ao-view to focus
- on a new, cross-platform ground station program. So ao-view may or
- may not be updated in the future. Mostly you just use
- the Log and Device menus. It has a wonderful display of the incoming
- flight data and I am sure you will enjoy what it has to say to you
- once you enable the voice output!
- </p><div class="section" title="FAQ"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2559795"></a>FAQ</h2></div></div></div><p>
- The altimeter (TeleMetrum) seems to shut off when disconnected from the
- computer. Make sure the battery is adequately charged. Remember the
- unit will pull more power than the USB port can deliver before the
- GPS enters "locked" mode. The battery charges best when TeleMetrum
- is turned off.
- </p><p>
- It's impossible to stop the TeleDongle when it's in "p" mode, I have
- to unplug the USB cable? Make sure you have tried to "escape out" of
- this mode. If this doesn't work the reboot procedure for the
- TeleDongle *is* to simply unplug it. 'cu' however will retain it's
- outgoing buffer IF your "escape out" ('~~') does not work.
- At this point using either 'ao-view' (or possibly
- 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
- communication.
- </p><p>
- The amber LED (on the TeleMetrum/altimeter) lights up when both
- battery and USB are connected. Does this mean it's charging?
- Yes, the yellow LED indicates the charging at the 'regular' rate.
- If the led is out but the unit is still plugged into a USB port,
- then the battery is being charged at a 'trickle' rate.
- </p><p>
- There are no "dit-dah-dah-dit" sound like the manual mentions?
- That's the "pad" mode. Weak batteries might be the problem.
- It is also possible that the unit is horizontal and the output
- is instead a "dit-dit" meaning 'idle'.
- </p><p>
- It's unclear how to use 'ao-view' and other programs when 'cu'
- is running. You cannot have more than one program connected to
- the TeleDongle at one time without apparent data loss as the
- incoming data will not make it to both programs intact.
- Disconnect whatever programs aren't currently being used.
- </p><p>
- How do I save flight data?
- Live telemetry is written to file(s) whenever 'ao-view' is connected
- to the TeleDongle. The file area defaults to ~/altos
- but is easily changed using the menus in 'ao-view'. The files that
- are written end in '.telem'. The after-flight
- data-dumped files will end in .eeprom and represent continuous data
- unlike the rf-linked .telem files that are subject to the
- turnarounds/data-packaging time slots in the half-duplex rf data path.
- See the above instructions on what and how to save the eeprom stored
- data after physically retrieving your TeleMetrum. Make sure to save
- the on-board data after each flight, as the current firmware will
- over-write any previous flight data during a new flight.
- </p></div></div><div class="chapter" title="Chapter 3. Specifications"><div class="titlepage"><div><div><h2 class="title"><a name="id2546901"></a>Chapter 3. Specifications</h2></div></div></div><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>
- Recording altimeter for model rocketry.
- </p></li><li class="listitem"><p>
- Supports dual deployment (can fire 2 ejection charges).
- </p></li><li class="listitem"><p>
- 70cm ham-band transceiver for telemetry downlink.
- </p></li><li class="listitem"><p>
- Barometric pressure sensor good to 45k feet MSL.
- </p></li><li class="listitem"><p>
- 1-axis high-g accelerometer for motor characterization, capable of
- +/- 50g using default part.
- </p></li><li class="listitem"><p>
- On-board, integrated GPS receiver with 5hz update rate capability.
- </p></li><li class="listitem"><p>
- On-board 1 megabyte non-volatile memory for flight data storage.
- </p></li><li class="listitem"><p>
- USB interface for battery charging, configuration, and data recovery.
- </p></li><li class="listitem"><p>
- Fully integrated support for LiPo rechargeable batteries.
- </p></li><li class="listitem"><p>
- Uses LiPo to fire e-matches, support for optional separate pyro
- battery if needed.
- </p></li><li class="listitem"><p>
- 2.75 x 1 inch board designed to fit inside 29mm airframe coupler tube.
- </p></li></ul></div></div><div class="chapter" title="Chapter 4. Handling Precautions"><div class="titlepage"><div><div><h2 class="title"><a name="id2574755"></a>Chapter 4. Handling Precautions</h2></div></div></div><p>
- TeleMetrum is a sophisticated electronic device. When handled gently and
- properly installed in an airframe, it will deliver impressive results.
- However, like all electronic devices, there are some precautions you
- must take.
- </p><p>
- The Lithium Polymer rechargeable batteries used with TeleMetrum 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 airframe. We
- often wrap them in suitable scraps of closed-cell packing foam before
- strapping them down, for example.
- </p><p>
- The TeleMetrum barometric sensor is sensitive to sunlight. In normal
- mounting situations, it and all of the other surface mount components
- are "down" towards whatever the underlying mounting surface is, so
- this is not normally a problem. Please consider this, though, when
- designing an installation, for example, in a 29mm airframe with a
- see-through plastic payload bay.
- </p><p>
- The TeleMetrum 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, but also by having a
- suitable static vent to outside air.
- </p><p>
- As with all other rocketry electronics, TeleMetrum must be protected
- from exposure to corrosive motor exhaust and ejection charge gasses.
- </p></div><div class="chapter" title="Chapter 5. Hardware Overview"><div class="titlepage"><div><div><h2 class="title"><a name="id2547133"></a>Chapter 5. Hardware Overview</h2></div></div></div><p>
- TeleMetrum is a 1 inch by 2.75 inch circuit board. It was designed to
- fit inside coupler for 29mm airframe tubing, but using it in a tube that
- small in diameter may require some creativity in mounting and wiring
- to succeed! The default 1/4
- wave UHF wire antenna attached to the center of the nose-cone end of
- the board is about 7 inches long, and wiring for a power switch and
- the e-matches for apogee and main ejection charges depart from the
- fin can end of the board. Given all this, an ideal "simple" avionics
- bay for TeleMetrum should have at least 10 inches of interior length.
- </p><p>
- A typical TeleMetrum installation using the on-board GPS antenna and
- default wire UHF antenna involves attaching only a suitable
- Lithium Polymer battery, a single pole switch for power on/off, and
- two pairs of wires connecting e-matches for the apogee and main ejection
- charges.
- </p><p>
- By default, we use the unregulated output of the LiPo 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, you can do so by adding
- a second 2mm connector to position B2 on the board and cutting the
- thick pcb trace connecting the LiPo battery to the pyro circuit between
- the two silk screen marks on the surface mount side of the board shown
- here [insert photo]
- </p><p>
- We offer two choices of pyro and power switch connector, or you can
- choose neither and solder wires directly to the board. All three choices
- are reasonable depending on the constraints of your airframe. Our
- favorite option when there is sufficient room above the board is to use
- the Tyco pin header with polarization and locking. If you choose this
- option, you crimp individual wires for the power switch and e-matches
- into a mating connector, and installing and removing the TeleMetrum
- board from an airframe is as easy as plugging or unplugging two
- connectors. If the airframe will not support this much height or if
- you want to be able to directly attach e-match leads to the board, we
- offer a screw terminal block. This is very similar to what most other
- altimeter vendors provide and so may be the most familiar option.
- You'll need a very small straight blade screwdriver to connect
- and disconnect the board in this case, such as you might find in a
- jeweler's screwdriver set. Finally, you can forego both options and
- solder wires directly to the board, which may be the best choice for
- minimum diameter and/or minimum mass designs.
- </p><p>
- For most airframes, the integrated GPS antenna and wire UHF antenna are
- a great combination. However, if you are installing in a carbon-fiber
- electronics bay which is opaque to RF signals, you may need to use
- off-board external antennas instead. In this case, you can order
- TeleMetrum with an SMA connector for the UHF antenna connection, and
- you can unplug the integrated GPS antenna and select an appropriate
- off-board GPS antenna with cable terminating in a U.FL connector.
- </p></div><div class="chapter" title="Chapter 6. Operation"><div class="titlepage"><div><div><h2 class="title"><a name="id2552998"></a>Chapter 6. Operation</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id2556146">Firmware Modes </a></span></dt><dt><span class="section"><a href="#id2557858">GPS </a></span></dt><dt><span class="section"><a href="#id2572262">Ground Testing </a></span></dt><dt><span class="section"><a href="#id2572259">Radio Link </a></span></dt><dt><span class="section"><a href="#id2542980">Configurable Parameters</a></span></dt><dd><dl><dt><span class="section"><a href="#id2563251">Radio Channel</a></span></dt><dt><span class="section"><a href="#id2554165">Apogee Delay</a></span></dt><dt><span class="section"><a href="#id2571971">Main Deployment Altitude</a></span></dt></dl></dd><dt><span class="section"><a href="#id2550600">Calibration</a></span></dt><dd><dl><dt><span class="section"><a href="#id2574322">Radio Frequency</a></span></dt><dt><span class="section"><a href="#id2564433">Accelerometer</a></span></dt></dl></dd></dl></div><div class="section" title="Firmware Modes"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2556146"></a>Firmware Modes </h2></div></div></div><p>
- The AltOS firmware build for TeleMetrum has two fundamental modes,
- "idle" and "flight". Which of these modes the firmware operates in
- is determined by the orientation of the rocket (well, actually the
- board, of course...) at the time power is switched on. If the rocket
- is "nose up", then TeleMetrum assumes it's on a rail or rod being
- prepared for launch, so the firmware chooses flight mode. However,
- if the rocket is more or less horizontal, the firmware instead enters
- idle mode.
- </p><p>
- At power on, you will hear three beeps
- ("S" in Morse code for startup) and then a pause while
- TeleMetrum completes initialization and self tests, and decides which
- mode to enter next.
- </p><p>
- In flight or "pad" mode, TeleMetrum turns on the GPS system,
- engages the flight
- state machine, goes into transmit-only mode on the RF link sending
- telemetry, and waits for launch to be detected. Flight mode is
- indicated by an audible "di-dah-dah-dit" ("P" for pad) on the
- beeper, followed by
- beeps indicating the state of the pyrotechnic igniter continuity.
- One beep indicates apogee continuity, two beeps indicate
- main continuity, three beeps indicate both apogee and main continuity,
- and one longer "brap" sound indicates no continuity. For a dual
- deploy flight, make sure you're getting three beeps before launching!
- For apogee-only or motor eject flights, do what makes sense.
- </p><p>
- In idle mode, you will hear an audible "di-dit" ("I" for idle), and
- the normal flight state machine is disengaged, thus
- no ejection charges will fire. TeleMetrum also listens on the RF
- link when in idle mode for packet mode requests sent from TeleDongle.
- Commands can be issued to a TeleMetrum in idle mode over either
- USB or the RF link equivalently.
- Idle mode is useful for configuring TeleMetrum, for extracting data
- from the on-board storage chip after flight, and for ground testing
- pyro charges.
- </p><p>
- One "neat trick" of particular value when TeleMetrum is used with very
- large airframes, 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 airframe to launch position, use a TeleDongle to open
- a packet connection, and issue a 'reset' command which will cause
- TeleMetrum to reboot, realize it's now nose-up, and thus choose
- 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!
- </p></div><div class="section" title="GPS"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2557858"></a>GPS </h2></div></div></div><p>
- TeleMetrum includes a complete GPS receiver. See a later section for
- a brief explanation of how GPS works that will help you understand
- the information in the telemetry stream. The bottom line is that
- the TeleMetrum GPS receiver needs to lock onto at least four
- satellites to obtain a solid 3 dimensional position fix and know
- what time it is!
- </p><p>
- TeleMetrum provides backup power to the GPS chip any time a LiPo
- battery is connected. This allows the receiver to "warm start" on
- the launch rail much faster than if every power-on were a "cold start"
- for the GPS receiver. In typical operations, powering up TeleMetrum
- on the flight line in idle mode while performing final airframe
- 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.
- </p></div><div class="section" title="Ground Testing"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2572262"></a>Ground Testing </h2></div></div></div><p>
- An important aspect of preparing a rocket using electronic deployment
- for flight is ground testing the recovery system. Thanks
- to the bi-directional RF link central to the Altus Metrum system,
- this can be accomplished in a TeleMetrum-equipped rocket without as
- much work as you may be accustomed to with other systems. It can
- even be fun!
- </p><p>
- Just prep the rocket for flight, then power up TeleMetrum while the
- airframe is horizontal. 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. Then, establish an
- RF packet connection from a TeleDongle-equipped computer using the
- P command from a safe distance. You can now command TeleMetrum to
- fire the apogee or main charges to complete your testing.
- </p><p>
- In order to reduce the chance of accidental firing of pyrotechnic
- charges, the command to fire a charge is intentionally somewhat
- difficult to type, and the built-in help is slightly cryptic to
- prevent accidental echoing of characters from the help text back at
- the board from firing a charge. The command to fire the apogee
- drogue charge is 'i DoIt drogue' and the command to fire the main
- charge is 'i DoIt main'.
- </p></div><div class="section" title="Radio Link"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2572259"></a>Radio Link </h2></div></div></div><p>
- The chip our boards are based on incorporates an RF transceiver, but
- it's not a full duplex system... each end can only be transmitting or
- receiving at any given moment. So we had to decide how to manage the
- link.
- </p><p>
- By design, TeleMetrum firmware listens for an RF connection when
- it's in "idle mode" (turned on while the rocket is horizontal), which
- allows us to use the RF link to configure the rocket, do things like
- ejection tests, and extract data after a flight without having to
- crack open the airframe. However, when the board is in "flight
- mode" (turned on when the rocket is vertical) the TeleMetrum 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 and out over
- the RF link in case the rocket crashes and we aren't able to extract
- data later...
- </p><p>
- We don't use a 'normal packet radio' mode because they're just too
- inefficient. The GFSK modulation we use is just FSK with the
- baseband pulses passed through a
- Gaussian filter before they go into the modulator to limit the
- transmitted bandwidth. When combined with the hardware forward error
- correction support in the cc1111 chip, this allows us to have a very
- robust 38.4 kilobit data link with only 10 milliwatts of transmit power,
- a whip antenna in the rocket, and a hand-held Yagi on the ground. We've
- had flights to above 21k feet AGL with good reception, and calculations
- suggest we should be good to well over 40k feet AGL with a 5-element yagi on
- the ground. We hope to fly boards to higher altitudes soon, and would
- of course appreciate customer feedback on performance in higher
- altitude flights!
- </p></div><div class="section" title="Configurable Parameters"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2542980"></a>Configurable Parameters</h2></div></div></div><p>
- Configuring a TeleMetrum board for flight is very simple. Because we
- have both acceleration and pressure sensors, there is no need to set
- a "mach delay", for example. The few configurable parameters can all
- be set using a simple terminal program over the USB port or RF link
- via TeleDongle.
- </p><div class="section" title="Radio Channel"><div class="titlepage"><div><div><h3 class="title"><a name="id2563251"></a>Radio Channel</h3></div></div></div><p>
- Our firmware supports 10 channels. The default channel 0 corresponds
- to a center frequency of 434.550 Mhz, and channels are spaced every
- 100 khz. Thus, channel 1 is 434.650 Mhz, and channel 9 is 435.550 Mhz.
- At any given launch, we highly recommend coordinating who will use
- each channel and when to avoid interference. And of course, both
- TeleMetrum and TeleDongle must be configured to the same channel to
- successfully communicate with each other.
- </p><p>
- To set the radio channel, use the 'c r' command, like 'c r 3' to set
- channel 3.
- As with all 'c' sub-commands, follow this with a 'c w' to write the
- change to the parameter block in the on-board DataFlash chip on
- your TeleMetrum board if you want the change to stay in place across reboots.
- </p></div><div class="section" title="Apogee Delay"><div class="titlepage"><div><div><h3 class="title"><a name="id2554165"></a>Apogee Delay</h3></div></div></div><p>
- Apogee delay is the number of seconds after TeleMetrum detects flight
- apogee that the drogue charge should be fired. In most cases, this
- should be left at the default of 0. However, if you are flying
- redundant electronics such as for an L3 certification, you may wish
- to set one of your altimeters to a positive delay so that both
- primary and backup pyrotechnic charges do not fire simultaneously.
- </p><p>
- To set the apogee delay, use the [FIXME] command.
- As with all 'c' sub-commands, follow this with a 'c w' to write the
- change to the parameter block in the on-board DataFlash chip.
- </p><p>
- Please note that the TeleMetrum apogee detection algorithm always
- fires a fraction of a second *after* apogee. If you are also flying
- an altimeter like the PerfectFlite MAWD, which only supports selecting
- 0 or 1 seconds of apogee delay, you may wish to set the MAWD to 0
- seconds delay and set the TeleMetrum to fire your backup 2 or 3
- seconds later to avoid any chance of both charges firing
- simultaneously. We've flown several airframes this way quite happily,
- including Keith's successful L3 cert.
- </p></div><div class="section" title="Main Deployment Altitude"><div class="titlepage"><div><div><h3 class="title"><a name="id2571971"></a>Main Deployment Altitude</h3></div></div></div><p>
- By default, TeleMetrum will fire the main deployment charge at an
- elevation of 250 meters (about 820 feet) above ground. We think this
- is a good elevation for most airframes, but feel free to change this
- to suit. In particular, if you are flying two altimeters, you may
- wish to set the
- deployment elevation for the backup altimeter to be something lower
- than the primary so that both pyrotechnic charges don't fire
- simultaneously.
- </p><p>
- To set the main deployment altitude, use the [FIXME] command.
- As with all 'c' sub-commands, follow this with a 'c w' to write the
- change to the parameter block in the on-board DataFlash chip.
- </p></div></div><div class="section" title="Calibration"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2550600"></a>Calibration</h2></div></div></div><p>
- There are only two calibrations required for a TeleMetrum board, and
- only one for TeleDongle.
- </p><div class="section" title="Radio Frequency"><div class="titlepage"><div><div><h3 class="title"><a name="id2574322"></a>Radio Frequency</h3></div></div></div><p>
- The radio frequency is synthesized from a clock based on the 48 Mhz
- crystal on the board. The actual frequency of this oscillator must be
- measured to generate a calibration constant. While our GFSK modulation
- bandwidth is wide enough to allow boards to communicate even when
- their oscillators are not on exactly the same frequency, performance
- is best when they are closely matched.
- Radio frequency calibration requires a calibrated frequency counter.
- Fortunately, once set, the variation in frequency due to aging and
- temperature changes is small enough that re-calibration by customers
- should generally not be required.
- </p><p>
- To calibrate the radio frequency, connect the UHF antenna port to a
- frequency counter, set the board to channel 0, and use the 'C'
- command to generate a CW carrier. Wait for the transmitter temperature
- to stabilize and the frequency to settle down.
- Then, divide 434.550 Mhz by the
- measured frequency and multiply by the current radio cal value show
- in the 'c s' command. For an unprogrammed board, the default value
- is 1186611. Take the resulting integer and program it using the 'c f'
- command. Testing with the 'C' command again should show a carrier
- within a few tens of Hertz of the intended frequency.
- As with all 'c' sub-commands, follow this with a 'c w' to write the
- change to the parameter block in the on-board DataFlash chip.
- </p></div><div class="section" title="Accelerometer"><div class="titlepage"><div><div><h3 class="title"><a name="id2564433"></a>Accelerometer</h3></div></div></div><p>
- The accelerometer we use has its own 5 volt power supply and
- the output must be passed through a resistive voltage divider to match
- the input of our 3.3 volt ADC. This means that unlike the barometric
- sensor, the output of the acceleration sensor is not ratiometric to
- the ADC converter, and calibration is required. We also support the
- use of any of several accelerometers from a Freescale family that
- includes at least +/- 40g, 50g, 100g, and 200g parts. Using gravity,
- a simple 2-point calibration yields acceptable results capturing both
- the different sensitivities and ranges of the different accelerometer
- parts and any variation in power supply voltages or resistor values
- in the divider network.
- </p><p>
- To calibrate the acceleration sensor, use the 'c a 0' command. You
- will be prompted to orient the board vertically with the UHF antenna
- up and press a key, then to orient the board vertically with the
- UHF antenna down and press a key.
- As with all 'c' sub-commands, follow this with a 'c w' to write the
- change to the parameter block in the on-board DataFlash chip.
- </p><p>
- The +1g and -1g calibration points are included in each telemetry
- frame and are part of the header extracted by ao-dumplog after flight.
- Note that we always store and return raw ADC samples for each
- sensor... nothing is permanently "lost" or "damaged" if the
- calibration is poor.
- </p></div></div></div><div class="chapter" title="Chapter 7. Updating Device Firmware"><div class="titlepage"><div><div><h2 class="title"><a name="id2554553"></a>Chapter 7. Updating Device Firmware</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id2569887">Updating TeleMetrum Firmware</a></span></dt><dt><span class="section"><a href="#id2552683">Updating TeleDongle Firmware</a></span></dt></dl></div><p>
- The big conceptual thing to realize is that you have to use a
- TeleDongle as a programmer to update a TeleMetrum, and vice versa.
- Due to limited memory resources in the cc1111, we don't support
- programming either unit directly over USB.
- </p><p>
- 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/.
- </p><p>
- We recommend updating TeleMetrum first, before updating TeleDongle.
- </p><div class="section" title="Updating TeleMetrum Firmware"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2569887"></a>Updating TeleMetrum Firmware</h2></div></div></div><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
- Find the 'programming cable' that you got as part of the starter
- kit, that has a red 8-pin MicroMaTch connector on one end and a
- red 4-pin MicroMaTch connector on the other end.
- </li><li class="listitem">
- Take the 2 screws out of the TeleDongle case to get access
- to the circuit board.
- </li><li class="listitem">
- Plug the 8-pin end of the programming cable to the
- matching connector on the TeleDongle, and the 4-pin end to the
- matching connector on the TeleMetrum.
- </li><li class="listitem">
- Attach a battery to the TeleMetrum board.
- </li><li class="listitem">
- Plug the TeleDongle into your computer's USB port, and power
- up the TeleMetrum.
- </li><li class="listitem">
- Run AltosUI, and select 'Flash Image' from the File menu.
- </li><li class="listitem">
- Pick the TeleDongle device from the list, identifying it as the
- programming device.
- </li><li class="listitem">
- Select the image you want put on the TeleMetrum, which should have a
- name in the form telemetrum-v1.0-0.7.1.ihx. It should be visible
- in the default directory, if not you may have to poke around
- your system to find it.
- </li><li class="listitem">
- Make sure the configuration parameters are reasonable
- looking. If the serial number and/or RF configuration
- values aren't right, you'll need to change them.
- </li><li class="listitem">
- Hit the 'OK' button and the software should proceed to flash
- the TeleMetrum with new firmware, showing a progress bar.
- </li><li class="listitem">
- Confirm that the TeleMetrum board seems to have updated ok, which you
- can do by plugging in to it over USB and using a terminal program
- to connect to the board and issue the 'v' command to check
- the version, etc.
- </li><li class="listitem">
- If something goes wrong, give it another try.
- </li></ol></div></div><div class="section" title="Updating TeleDongle Firmware"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2552683"></a>Updating TeleDongle Firmware</h2></div></div></div><p>
- Updating TeleDongle's firmware is just like updating TeleMetrum
- firmware, but you switch which board is the programmer and which
- is the programming target.
- </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
- Find the 'programming cable' that you got as part of the starter
- kit, that has a red 8-pin MicroMaTch connector on one end and a
- red 4-pin MicroMaTch connector on the other end.
- </li><li class="listitem">
- Find the USB cable that you got as part of the starter kit, and
- plug the "mini" end in to the mating connector on TeleMetrum.
- </li><li class="listitem">
- Take the 2 screws out of the TeleDongle case to get access
- to the circuit board.
- </li><li class="listitem">
- Plug the 8-pin end of the programming cable to the (latching)
- matching connector on the TeleMetrum, and the 4-pin end to the
- matching connector on the TeleDongle.
- </li><li class="listitem">
- Attach a battery to the TeleMetrum board.
- </li><li class="listitem">
- Plug both TeleMetrum and TeleDongle into your computer's USB
- ports, and power up the TeleMetrum.
- </li><li class="listitem">
- Run AltosUI, and select 'Flash Image' from the File menu.
- </li><li class="listitem">
- Pick the TeleMongle device from the list, identifying it as the
- programming device.
- </li><li class="listitem">
- Select the image you want put on the TeleDongle, which should have a
- name in the form teledongle-v0.2-0.7.1.ihx. It should be visible
- in the default directory, if not you may have to poke around
- your system to find it.
- </li><li class="listitem">
- Make sure the configuration parameters are reasonable
- looking. If the serial number and/or RF configuration
- values aren't right, you'll need to change them. The TeleDongle
- serial number is on the "bottom" of the circuit board, and can
- usually be read through the translucent blue plastic case without
- needing to remove the board from the case.
- </li><li class="listitem">
- Hit the 'OK' button and the software should proceed to flash
- the TeleDongle with new firmware, showing a progress bar.
- </li><li class="listitem">
- Confirm that the TeleDongle board seems to have updated ok, which you
- can do by plugging in to it over USB and using a terminal program
- to connect to the board and issue the 'v' command to check
- the version, etc. Once you're happy, remove the programming cable
- and put the cover back on the TeleDongle.
- </li><li class="listitem">
- If something goes wrong, give it another try.
- </li></ol></div><p>
- 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.
- </p></div></div><div class="chapter" title="Chapter 8. Using Altus Metrum Products"><div class="titlepage"><div><div><h2 class="title"><a name="id2539483"></a>Chapter 8. Using Altus Metrum Products</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id2558109">Being Legal</a></span></dt><dd><dl><dt><span class="section"><a href="#id2554650">In the Rocket</a></span></dt><dt><span class="section"><a href="#id2572268">On the Ground</a></span></dt><dt><span class="section"><a href="#id2569008">Data Analysis</a></span></dt><dt><span class="section"><a href="#id2563568">Future Plans</a></span></dt></dl></dd><dt><span class="section"><a href="#id2567979">
- How GPS Works
- </a></span></dt></dl></div><div class="section" title="Being Legal"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2558109"></a>Being Legal</h2></div></div></div><p>
- First off, in the US, you need an [amateur radio license](../Radio) or
- other authorization to legally operate the radio transmitters that are part
- of our products.
- </p><div class="section" title="In the Rocket"><div class="titlepage"><div><div><h3 class="title"><a name="id2554650"></a>In the Rocket</h3></div></div></div><p>
- In the rocket itself, you just need a [TeleMetrum](../TeleMetrum) board and
- a LiPo rechargeable battery. An 860mAh battery weighs less than a 9V
- alkaline battery, and will run a [TeleMetrum](../TeleMetrum) for hours.
- </p><p>
- By default, we ship TeleMetrum with a simple wire antenna. If your
- electronics bay or the airframe it resides within is made of carbon fiber,
- which is opaque to RF signals, you may choose to have an SMA connector
- installed so that you can run a coaxial cable to an antenna mounted
- elsewhere in the rocket.
- </p></div><div class="section" title="On the Ground"><div class="titlepage"><div><div><h3 class="title"><a name="id2572268"></a>On the Ground</h3></div></div></div><p>
- To receive the data stream from the rocket, you need an antenna and short
- feedline connected to one of our [TeleDongle](../TeleDongle) units. The
- TeleDongle in turn plugs directly into the USB port on a notebook
- computer. Because TeleDongle looks like a simple serial port, your computer
- does not require special device drivers... just plug it in.
- </p><p>
- Right now, all of our application software is written for Linux. However,
- because we understand that many people run Windows or MacOS, we are working
- on a new ground station program written in Java that should work on all
- operating systems.
- </p><p>
- After the flight, you can use the RF link to extract the more detailed data
- logged in the rocket, or you can use a mini USB cable to plug into the
- TeleMetrum board directly. Pulling out the data without having to open up
- the rocket is pretty cool! A USB cable is also how you charge the LiPo
- 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.
- </p><p>
- If your rocket lands out of sight, you may enjoy having a hand-held GPS
- receiver, so that you can put in a waypoint for the last reported rocket
- position before touch-down. This makes looking for your rocket a lot like
- Geo-Cacheing... just go to the waypoint and look around starting from there.
- </p><p>
- You may also enjoy having a ham radio "HT" that covers the 70cm band... you
- can use that with your antenna to direction-find the rocket on the ground
- the same way you can use a Walston or Beeline tracker. This can be handy
- if the rocket is hiding in sage brush or a tree, or if the last GPS position
- doesn't get you close enough because the rocket dropped into a canyon, or
- the wind is blowing it across a dry lake bed, or something like that... Keith
- and Bdale both currently own and use the Yaesu VX-7R at launches.
- </p><p>
- So, to recap, on the ground the hardware you'll need includes:
- </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
- an antenna and feedline
- </li><li class="listitem">
- a TeleDongle
- </li><li class="listitem">
- a notebook computer
- </li><li class="listitem">
- optionally, a handheld GPS receiver
- </li><li class="listitem">
- optionally, an HT or receiver covering 435 Mhz
- </li></ol></div><p>
- </p><p>
- The best hand-held commercial directional antennas we've found for radio
- direction finding rockets are from
- <a class="ulink" href="http://www.arrowantennas.com/" target="_top">
- Arrow Antennas.
- </a>
- The 440-3 and 440-5 are both good choices for finding a
- TeleMetrum-equipped rocket when used with a suitable 70cm HT.
- </p></div><div class="section" title="Data Analysis"><div class="titlepage"><div><div><h3 class="title"><a name="id2569008"></a>Data Analysis</h3></div></div></div><p>
- Our software makes it easy to log the data from each flight, both the
- telemetry received over the RF link during the flight itself, and the more
- complete data log recorded in the DataFlash memory on the TeleMetrum
- board. Once this data is on your computer, our postflight 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 data file
- useable with Google Maps and Google Earth for visualizing the flight path
- in two or three dimensions!
- </p><p>
- 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.
- </p></div><div class="section" title="Future Plans"><div class="titlepage"><div><div><h3 class="title"><a name="id2563568"></a>Future Plans</h3></div></div></div><p>
- In the future, we intend to offer "companion boards" for the rocket that will
- plug in to TeleMetrum to collect additional data, provide more pyro channels,
- and so forth. A reference design for a companion board will be documented
- soon, and will be compatible with open source Arduino programming tools.
- </p><p>
- We are also working on the design of a hand-held ground terminal that will
- allow monitoring the rocket's status, collecting data during flight, and
- logging data after flight without the need for a notebook computer on the
- flight line. Particularly since it is so difficult to read most notebook
- screens in direct sunlight, we think this will be a great thing to have.
- </p><p>
- 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...
- </p></div></div><div class="section" title="How GPS Works"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2567979"></a>
- How GPS Works
- </h2></div></div></div><p>
- Placeholder.
- </p></div></div></div></body></html>
## Artifacts ##
-The user manual for TeleMetrum is available in
-[html](doc/telemetrum-doc.html) and [pdf](doc/telemetrum-doc.pdf)
-formats.
+There is a single manual for TeleMetrum and all other Altus Metrum products,
+which is available in [html](../AltOS/doc/altusmetrum.html) and
+[pdf](../AltOS/doc/altusmetrum.pdf) formats.
The hardware design current gEDA files are available from
[git.gag.com](http://git.gag.com) in the project
projects / web / altusmetrum / commitdiff