1 <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>
2 This document is released under the terms of the
3 <a class="ulink" href="http://creativecommons.org/licenses/by-sa/3.0/" target="_top">
4 Creative Commons ShareAlike 3.0
7 </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">
8 Add instructions for re-flashing devices using AltosUI
9 </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">
11 </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>
12 Welcome to the Altus Metrum community! Our circuits and software reflect
13 our passion for both hobby rocketry and Free Software. We hope their
14 capabilities and performance will delight you in every way, but by
15 releasing all of our hardware and software designs under open licenses,
16 we also hope to empower you to take as active a role in our collective
19 The focal point of our community is TeleMetrum, a dual deploy altimeter
20 with fully integrated GPS and radio telemetry as standard features, and
21 a "companion interface" that will support optional capabilities in the
24 Complementing TeleMetrum is TeleDongle, a USB to RF interface for
25 communicating with TeleMetrum. Combined with your choice of antenna and
26 notebook computer, TeleDongle and our associated user interface software
27 form a complete ground station capable of logging and displaying in-flight
28 telemetry, aiding rocket recovery, then processing and archiving flight
29 data for analysis and review.
31 More products will be added to the Altus Metrum family over time, and
32 we currently envision that this will be a single, comprehensive manual
33 for the entire product family.
34 </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>
35 This chapter began as "The Mere-Mortals Quick Start/Usage Guide to
36 the Altus Metrum Starter Kit" by Bob Finch, W9YA, NAR 12965, TRA 12350,
37 w9ya@amsat.org. Bob was one of our first customers for a production
38 TeleMetrum, and the enthusiasm that led to his contribution of this
39 section is immensely gratifying and highy appreciated!
41 The first thing to do after you check the inventory of parts in your
42 "starter kit" is to charge the battery by plugging it into the
43 corresponding socket of the TeleMetrum and then using the USB A to B
44 cable to plug the Telemetrum into your computer's USB socket. The
45 TeleMetrum circuitry will charge the battery whenever it is plugged
46 into the usb socket. The TeleMetrum's on-off switch does NOT control
47 the charging circuitry. When the GPS chip is initially searching for
48 satellites, the unit will pull more current than it can pull from the
49 usb port, so the battery must be plugged in order to get a good
50 satellite lock. Once GPS is locked the current consumption goes back
51 down enough to enable charging while
52 running. So it's a good idea to fully charge the battery as your
53 first item of business so there is no issue getting and maintaining
54 satellite lock. The yellow charge indicator led will go out when the
55 battery is nearly full and the charger goes to trickle charge.
57 The other active device in the starter kit is the half-duplex TeleDongle
58 rf link. If you plug it in to your computer it should "just work",
59 showing up as a serial port device. If you are using Linux and are
60 having problems, try moving to a fresher kernel (2.6.33 or newer), as
61 there were some ugly USB serial driver bugs in earlier versions.
63 Next you should obtain and install the AltOS utilities. The first
64 generation sofware was written for Linux only. New software is coming
65 soon that will also run on Windows and Mac. For now, we'll concentrate
66 on Linux. If you are using Debian, an 'altos' package already exists,
67 see http://altusmetrum.org/AltOS for details on how to install it.
68 User-contributed directions for building packages on ArchLinux may be
69 found in the contrib/arch-linux directory as PKGBUILD files.
70 Between the debian/rules file and the PKGBUILD files in
71 contrib, you should find enough information to learn how to build the
72 software for any other version of Linux.
74 When you have successfully installed the software suite (either from
75 compiled source code or as the pre-built Debian package) you will
76 have 10 or so executable programs all of which have names beginning
78 ('ao-view' is the lone GUI-based program, the rest are command-line
79 oriented.) You will also have man pages, that give you basic info
81 You will also get this documentation in two file types in the doc/
82 directory, telemetrum-doc.pdf and telemetrum-doc.html.
83 Finally you will have a couple control files that allow the ao-view
84 GUI-based program to appear in your menu of programs (under
85 the 'Internet' category).
87 Both Telemetrum and TeleDongle can be directly communicated
88 with using USB ports. The first thing you should try after getting
89 both units plugged into to your computer's usb port(s) is to run
90 'ao-list' from a terminal-window to see what port-device-name each
91 device has been assigned by the operating system.
92 You will need this information to access the devices via their
93 respective on-board firmware and data using other command line
94 programs in the AltOS software suite.
96 To access the device's firmware for configuration you need a terminal
97 program such as you would use to talk to a modem. The software
98 authors prefer using the program 'cu' which comes from the UUCP package
99 on most Unix-like systems such as Linux. An example command line for
100 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
101 indicated from running the
102 ao-list program. Another reasonable terminal program for Linux is
103 'cutecom'. The default 'escape'
104 character used by CU (i.e. the character you use to
105 issue commands to cu itself instead of sending the command as input
106 to the connected device) is a '~'. You will need this for use in
107 only two different ways during normal operations. First is to exit
108 the program by sending a '~.' which is called a 'escape-disconnect'
109 and allows you to close-out from 'cu'. The
110 second use will be outlined later.
112 Both TeleMetrum and TeleDongle share the concept of a two level
113 command set in their firmware.
114 The first layer has several single letter commands. Once
115 you are using 'cu' (or 'cutecom') sending (typing) a '?'
116 returns a full list of these
117 commands. The second level are configuration sub-commands accessed
118 using the 'c' command, for
119 instance typing 'c?' will give you this second level of commands
120 (all of which require the
121 letter 'c' to access). Please note that most configuration options
122 are stored only in DataFlash memory, and only TeleMetrum has this
123 memory to save the various values entered like the channel number
124 and your callsign when powered off. TeleDongle requires that you
125 set these each time you plug it in, which ao-view can help with.
127 Try setting these config ('c' or second level menu) values. A good
128 place to start is by setting your call sign. By default, the boards
129 use 'N0CALL' which is cute, but not exactly legal!
130 Spend a few minutes getting comfortable with the units, their
131 firmware, and 'cu' (or possibly 'cutecom').
132 For instance, try to send
133 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
134 Verify you can connect and disconnect from the units while in your
135 terminal program by sending the escape-disconnect mentioned above.
137 Note that the 'reboot' command, which is very useful on TeleMetrum,
138 will likely just cause problems with the dongle. The *correct* way
139 to reset the dongle is just to unplug and re-plug it.
141 A fun thing to do at the launch site and something you can do while
142 learning how to use these units is to play with the rf-link access
143 of the TeleMetrum from the TeleDongle. Be aware that you *must* create
144 some physical separation between the devices, otherwise the link will
145 not function due to signal overload in the receivers in each device.
147 Now might be a good time to take a break and read the rest of this
148 manual, particularly about the two "modes" that the TeleMetrum
149 can be placed in and how the position of the TeleMetrum when booting
150 up will determine whether the unit is in "pad" or "idle" mode.
152 You can access a TeleMetrum in idle mode from the Teledongle's USB
153 connection using the rf link
154 by issuing a 'p' command to the TeleDongle. Practice connecting and
155 disconnecting ('~~' while using 'cu') from the TeleMetrum. If
156 you cannot escape out of the "p" command, (by using a '~~' when in
157 CU) then it is likely that your kernel has issues. Try a newer version.
159 Using this rf link allows you to configure the TeleMetrum, test
160 fire e-matches and igniters from the flight line, check pyro-match
161 continuity and so forth. You can leave the unit turned on while it
162 is in 'idle mode' and then place the
163 rocket vertically on the launch pad, walk away and then issue a
164 reboot command. The TeleMetrum will reboot and start sending data
165 having changed to the "pad" mode. If the TeleDongle is not receiving
166 this data, you can disconnect 'cu' from the Teledongle using the
167 procedures mentioned above and THEN connect to the TeleDongle from
168 inside 'ao-view'. If this doesn't work, disconnect from the
169 TeleDongle, unplug it, and try again after plugging it back in.
171 Eventually the GPS will find enough satellites, lock in on them,
172 and 'ao-view' will both auditorially announce and visually indicate
174 Now you can launch knowing that you have a good data path and
175 good satellite lock for flight data and recovery. Remember
176 you MUST tell ao-view to connect to the TeleDongle explicitly in
177 order for ao-view to be able to receive data.
179 Both RDF (radio direction finding) tones from the TeleMetrum and
180 GPS trekking data are available and together are very useful in
181 locating the rocket once it has landed. (The last good GPS data
182 received before touch-down will be on the data screen of 'ao-view'.)
184 Once you have recovered the rocket you can download the eeprom
185 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
186 either a USB cable or over the radio link using TeleDongle.
187 And by following the man page for 'ao-postflight' you can create
188 various data output reports, graphs, and even kml data to see the
189 flight trajectory in google-earth. (Moving the viewing angle making
190 sure to connect the yellow lines while in google-earth is the proper
193 As for ao-view.... some things are in the menu but don't do anything
194 very useful. The developers have stopped working on ao-view to focus
195 on a new, cross-platform ground station program. So ao-view may or
196 may not be updated in the future. Mostly you just use
197 the Log and Device menus. It has a wonderful display of the incoming
198 flight data and I am sure you will enjoy what it has to say to you
199 once you enable the voice output!
200 </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>
201 The altimeter (TeleMetrum) seems to shut off when disconnected from the
202 computer. Make sure the battery is adequately charged. Remember the
203 unit will pull more power than the USB port can deliver before the
204 GPS enters "locked" mode. The battery charges best when TeleMetrum
207 It's impossible to stop the TeleDongle when it's in "p" mode, I have
208 to unplug the USB cable? Make sure you have tried to "escape out" of
209 this mode. If this doesn't work the reboot procedure for the
210 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
211 outgoing buffer IF your "escape out" ('~~') does not work.
212 At this point using either 'ao-view' (or possibly
213 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
216 The amber LED (on the TeleMetrum/altimeter) lights up when both
217 battery and USB are connected. Does this mean it's charging?
218 Yes, the yellow LED indicates the charging at the 'regular' rate.
219 If the led is out but the unit is still plugged into a USB port,
220 then the battery is being charged at a 'trickle' rate.
222 There are no "dit-dah-dah-dit" sound like the manual mentions?
223 That's the "pad" mode. Weak batteries might be the problem.
224 It is also possible that the unit is horizontal and the output
225 is instead a "dit-dit" meaning 'idle'.
227 It's unclear how to use 'ao-view' and other programs when 'cu'
228 is running. You cannot have more than one program connected to
229 the TeleDongle at one time without apparent data loss as the
230 incoming data will not make it to both programs intact.
231 Disconnect whatever programs aren't currently being used.
233 How do I save flight data?
234 Live telemetry is written to file(s) whenever 'ao-view' is connected
235 to the TeleDongle. The file area defaults to ~/altos
236 but is easily changed using the menus in 'ao-view'. The files that
237 are written end in '.telem'. The after-flight
238 data-dumped files will end in .eeprom and represent continuous data
239 unlike the rf-linked .telem files that are subject to the
240 turnarounds/data-packaging time slots in the half-duplex rf data path.
241 See the above instructions on what and how to save the eeprom stored
242 data after physically retrieving your TeleMetrum. Make sure to save
243 the on-board data after each flight, as the current firmware will
244 over-write any previous flight data during a new flight.
245 </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>
246 Recording altimeter for model rocketry.
247 </p></li><li class="listitem"><p>
248 Supports dual deployment (can fire 2 ejection charges).
249 </p></li><li class="listitem"><p>
250 70cm ham-band transceiver for telemetry downlink.
251 </p></li><li class="listitem"><p>
252 Barometric pressure sensor good to 45k feet MSL.
253 </p></li><li class="listitem"><p>
254 1-axis high-g accelerometer for motor characterization, capable of
255 +/- 50g using default part.
256 </p></li><li class="listitem"><p>
257 On-board, integrated GPS receiver with 5hz update rate capability.
258 </p></li><li class="listitem"><p>
259 On-board 1 megabyte non-volatile memory for flight data storage.
260 </p></li><li class="listitem"><p>
261 USB interface for battery charging, configuration, and data recovery.
262 </p></li><li class="listitem"><p>
263 Fully integrated support for LiPo rechargeable batteries.
264 </p></li><li class="listitem"><p>
265 Uses LiPo to fire e-matches, support for optional separate pyro
267 </p></li><li class="listitem"><p>
268 2.75 x 1 inch board designed to fit inside 29mm airframe coupler tube.
269 </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>
270 TeleMetrum is a sophisticated electronic device. When handled gently and
271 properly installed in an airframe, it will deliver impressive results.
272 However, like all electronic devices, there are some precautions you
275 The Lithium Polymer rechargeable batteries used with TeleMetrum have an
276 extraordinary power density. This is great because we can fly with
277 much less battery mass than if we used alkaline batteries or previous
278 generation rechargeable batteries... but if they are punctured
279 or their leads are allowed to short, they can and will release their
281 Thus we recommend that you take some care when handling our batteries
282 and consider giving them some extra protection in your airframe. We
283 often wrap them in suitable scraps of closed-cell packing foam before
284 strapping them down, for example.
286 The TeleMetrum barometric sensor is sensitive to sunlight. In normal
287 mounting situations, it and all of the other surface mount components
288 are "down" towards whatever the underlying mounting surface is, so
289 this is not normally a problem. Please consider this, though, when
290 designing an installation, for example, in a 29mm airframe with a
291 see-through plastic payload bay.
293 The TeleMetrum barometric sensor sampling port must be able to
295 both by not being covered by foam or tape or other materials that might
296 directly block the hole on the top of the sensor, but also by having a
297 suitable static vent to outside air.
299 As with all other rocketry electronics, TeleMetrum must be protected
300 from exposure to corrosive motor exhaust and ejection charge gasses.
301 </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>
302 TeleMetrum is a 1 inch by 2.75 inch circuit board. It was designed to
303 fit inside coupler for 29mm airframe tubing, but using it in a tube that
304 small in diameter may require some creativity in mounting and wiring
305 to succeed! The default 1/4
306 wave UHF wire antenna attached to the center of the nose-cone end of
307 the board is about 7 inches long, and wiring for a power switch and
308 the e-matches for apogee and main ejection charges depart from the
309 fin can end of the board. Given all this, an ideal "simple" avionics
310 bay for TeleMetrum should have at least 10 inches of interior length.
312 A typical TeleMetrum installation using the on-board GPS antenna and
313 default wire UHF antenna involves attaching only a suitable
314 Lithium Polymer battery, a single pole switch for power on/off, and
315 two pairs of wires connecting e-matches for the apogee and main ejection
318 By default, we use the unregulated output of the LiPo battery directly
319 to fire ejection charges. This works marvelously with standard
320 low-current e-matches like the J-Tek from MJG Technologies, and with
321 Quest Q2G2 igniters. However, if you
322 want or need to use a separate pyro battery, you can do so by adding
323 a second 2mm connector to position B2 on the board and cutting the
324 thick pcb trace connecting the LiPo battery to the pyro circuit between
325 the two silk screen marks on the surface mount side of the board shown
328 We offer two choices of pyro and power switch connector, or you can
329 choose neither and solder wires directly to the board. All three choices
330 are reasonable depending on the constraints of your airframe. Our
331 favorite option when there is sufficient room above the board is to use
332 the Tyco pin header with polarization and locking. If you choose this
333 option, you crimp individual wires for the power switch and e-matches
334 into a mating connector, and installing and removing the TeleMetrum
335 board from an airframe is as easy as plugging or unplugging two
336 connectors. If the airframe will not support this much height or if
337 you want to be able to directly attach e-match leads to the board, we
338 offer a screw terminal block. This is very similar to what most other
339 altimeter vendors provide and so may be the most familiar option.
340 You'll need a very small straight blade screwdriver to connect
341 and disconnect the board in this case, such as you might find in a
342 jeweler's screwdriver set. Finally, you can forego both options and
343 solder wires directly to the board, which may be the best choice for
344 minimum diameter and/or minimum mass designs.
346 For most airframes, the integrated GPS antenna and wire UHF antenna are
347 a great combination. However, if you are installing in a carbon-fiber
348 electronics bay which is opaque to RF signals, you may need to use
349 off-board external antennas instead. In this case, you can order
350 TeleMetrum with an SMA connector for the UHF antenna connection, and
351 you can unplug the integrated GPS antenna and select an appropriate
352 off-board GPS antenna with cable terminating in a U.FL connector.
353 </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>
354 The AltOS firmware build for TeleMetrum has two fundamental modes,
355 "idle" and "flight". Which of these modes the firmware operates in
356 is determined by the orientation of the rocket (well, actually the
357 board, of course...) at the time power is switched on. If the rocket
358 is "nose up", then TeleMetrum assumes it's on a rail or rod being
359 prepared for launch, so the firmware chooses flight mode. However,
360 if the rocket is more or less horizontal, the firmware instead enters
363 At power on, you will hear three beeps
364 ("S" in Morse code for startup) and then a pause while
365 TeleMetrum completes initialization and self tests, and decides which
368 In flight or "pad" mode, TeleMetrum turns on the GPS system,
370 state machine, goes into transmit-only mode on the RF link sending
371 telemetry, and waits for launch to be detected. Flight mode is
372 indicated by an audible "di-dah-dah-dit" ("P" for pad) on the
374 beeps indicating the state of the pyrotechnic igniter continuity.
375 One beep indicates apogee continuity, two beeps indicate
376 main continuity, three beeps indicate both apogee and main continuity,
377 and one longer "brap" sound indicates no continuity. For a dual
378 deploy flight, make sure you're getting three beeps before launching!
379 For apogee-only or motor eject flights, do what makes sense.
381 In idle mode, you will hear an audible "di-dit" ("I" for idle), and
382 the normal flight state machine is disengaged, thus
383 no ejection charges will fire. TeleMetrum also listens on the RF
384 link when in idle mode for packet mode requests sent from TeleDongle.
385 Commands can be issued to a TeleMetrum in idle mode over either
386 USB or the RF link equivalently.
387 Idle mode is useful for configuring TeleMetrum, for extracting data
388 from the on-board storage chip after flight, and for ground testing
391 One "neat trick" of particular value when TeleMetrum is used with very
392 large airframes, is that you can power the board up while the rocket
393 is horizontal, such that it comes up in idle mode. Then you can
394 raise the airframe to launch position, use a TeleDongle to open
395 a packet connection, and issue a 'reset' command which will cause
396 TeleMetrum to reboot, realize it's now nose-up, and thus choose
397 flight mode. This is much safer than standing on the top step of a
398 rickety step-ladder or hanging off the side of a launch tower with
399 a screw-driver trying to turn on your avionics before installing
401 </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>
402 TeleMetrum includes a complete GPS receiver. See a later section for
403 a brief explanation of how GPS works that will help you understand
404 the information in the telemetry stream. The bottom line is that
405 the TeleMetrum GPS receiver needs to lock onto at least four
406 satellites to obtain a solid 3 dimensional position fix and know
409 TeleMetrum provides backup power to the GPS chip any time a LiPo
410 battery is connected. This allows the receiver to "warm start" on
411 the launch rail much faster than if every power-on were a "cold start"
412 for the GPS receiver. In typical operations, powering up TeleMetrum
413 on the flight line in idle mode while performing final airframe
414 preparation will be sufficient to allow the GPS receiver to cold
415 start and acquire lock. Then the board can be powered down during
416 RSO review and installation on a launch rod or rail. When the board
417 is turned back on, the GPS system should lock very quickly, typically
418 long before igniter installation and return to the flight line are
420 </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>
421 An important aspect of preparing a rocket using electronic deployment
422 for flight is ground testing the recovery system. Thanks
423 to the bi-directional RF link central to the Altus Metrum system,
424 this can be accomplished in a TeleMetrum-equipped rocket without as
425 much work as you may be accustomed to with other systems. It can
428 Just prep the rocket for flight, then power up TeleMetrum while the
429 airframe is horizontal. This will cause the firmware to go into
430 "idle" mode, in which the normal flight state machine is disabled and
431 charges will not fire without manual command. Then, establish an
432 RF packet connection from a TeleDongle-equipped computer using the
433 P command from a safe distance. You can now command TeleMetrum to
434 fire the apogee or main charges to complete your testing.
436 In order to reduce the chance of accidental firing of pyrotechnic
437 charges, the command to fire a charge is intentionally somewhat
438 difficult to type, and the built-in help is slightly cryptic to
439 prevent accidental echoing of characters from the help text back at
440 the board from firing a charge. The command to fire the apogee
441 drogue charge is 'i DoIt drogue' and the command to fire the main
442 charge is 'i DoIt main'.
443 </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>
444 The chip our boards are based on incorporates an RF transceiver, but
445 it's not a full duplex system... each end can only be transmitting or
446 receiving at any given moment. So we had to decide how to manage the
449 By design, TeleMetrum firmware listens for an RF connection when
450 it's in "idle mode" (turned on while the rocket is horizontal), which
451 allows us to use the RF link to configure the rocket, do things like
452 ejection tests, and extract data after a flight without having to
453 crack open the airframe. However, when the board is in "flight
454 mode" (turned on when the rocket is vertical) the TeleMetrum only
455 transmits and doesn't listen at all. That's because we want to put
456 ultimate priority on event detection and getting telemetry out of
457 the rocket and out over
458 the RF link in case the rocket crashes and we aren't able to extract
461 We don't use a 'normal packet radio' mode because they're just too
462 inefficient. The GFSK modulation we use is just FSK with the
463 baseband pulses passed through a
464 Gaussian filter before they go into the modulator to limit the
465 transmitted bandwidth. When combined with the hardware forward error
466 correction support in the cc1111 chip, this allows us to have a very
467 robust 38.4 kilobit data link with only 10 milliwatts of transmit power,
468 a whip antenna in the rocket, and a hand-held Yagi on the ground. We've
469 had flights to above 21k feet AGL with good reception, and calculations
470 suggest we should be good to well over 40k feet AGL with a 5-element yagi on
471 the ground. We hope to fly boards to higher altitudes soon, and would
472 of course appreciate customer feedback on performance in higher
474 </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>
475 Configuring a TeleMetrum board for flight is very simple. Because we
476 have both acceleration and pressure sensors, there is no need to set
477 a "mach delay", for example. The few configurable parameters can all
478 be set using a simple terminal program over the USB port or RF link
480 </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>
481 Our firmware supports 10 channels. The default channel 0 corresponds
482 to a center frequency of 434.550 Mhz, and channels are spaced every
483 100 khz. Thus, channel 1 is 434.650 Mhz, and channel 9 is 435.550 Mhz.
484 At any given launch, we highly recommend coordinating who will use
485 each channel and when to avoid interference. And of course, both
486 TeleMetrum and TeleDongle must be configured to the same channel to
487 successfully communicate with each other.
489 To set the radio channel, use the 'c r' command, like 'c r 3' to set
491 As with all 'c' sub-commands, follow this with a 'c w' to write the
492 change to the parameter block in the on-board DataFlash chip on
493 your TeleMetrum board if you want the change to stay in place across reboots.
494 </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>
495 Apogee delay is the number of seconds after TeleMetrum detects flight
496 apogee that the drogue charge should be fired. In most cases, this
497 should be left at the default of 0. However, if you are flying
498 redundant electronics such as for an L3 certification, you may wish
499 to set one of your altimeters to a positive delay so that both
500 primary and backup pyrotechnic charges do not fire simultaneously.
502 To set the apogee delay, use the [FIXME] command.
503 As with all 'c' sub-commands, follow this with a 'c w' to write the
504 change to the parameter block in the on-board DataFlash chip.
506 Please note that the TeleMetrum apogee detection algorithm always
507 fires a fraction of a second *after* apogee. If you are also flying
508 an altimeter like the PerfectFlite MAWD, which only supports selecting
509 0 or 1 seconds of apogee delay, you may wish to set the MAWD to 0
510 seconds delay and set the TeleMetrum to fire your backup 2 or 3
511 seconds later to avoid any chance of both charges firing
512 simultaneously. We've flown several airframes this way quite happily,
513 including Keith's successful L3 cert.
514 </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>
515 By default, TeleMetrum will fire the main deployment charge at an
516 elevation of 250 meters (about 820 feet) above ground. We think this
517 is a good elevation for most airframes, but feel free to change this
518 to suit. In particular, if you are flying two altimeters, you may
520 deployment elevation for the backup altimeter to be something lower
521 than the primary so that both pyrotechnic charges don't fire
524 To set the main deployment altitude, use the [FIXME] command.
525 As with all 'c' sub-commands, follow this with a 'c w' to write the
526 change to the parameter block in the on-board DataFlash chip.
527 </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>
528 There are only two calibrations required for a TeleMetrum board, and
529 only one for TeleDongle.
530 </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>
531 The radio frequency is synthesized from a clock based on the 48 Mhz
532 crystal on the board. The actual frequency of this oscillator must be
533 measured to generate a calibration constant. While our GFSK modulation
534 bandwidth is wide enough to allow boards to communicate even when
535 their oscillators are not on exactly the same frequency, performance
536 is best when they are closely matched.
537 Radio frequency calibration requires a calibrated frequency counter.
538 Fortunately, once set, the variation in frequency due to aging and
539 temperature changes is small enough that re-calibration by customers
540 should generally not be required.
542 To calibrate the radio frequency, connect the UHF antenna port to a
543 frequency counter, set the board to channel 0, and use the 'C'
544 command to generate a CW carrier. Wait for the transmitter temperature
545 to stabilize and the frequency to settle down.
546 Then, divide 434.550 Mhz by the
547 measured frequency and multiply by the current radio cal value show
548 in the 'c s' command. For an unprogrammed board, the default value
549 is 1186611. Take the resulting integer and program it using the 'c f'
550 command. Testing with the 'C' command again should show a carrier
551 within a few tens of Hertz of the intended frequency.
552 As with all 'c' sub-commands, follow this with a 'c w' to write the
553 change to the parameter block in the on-board DataFlash chip.
554 </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>
555 The accelerometer we use has its own 5 volt power supply and
556 the output must be passed through a resistive voltage divider to match
557 the input of our 3.3 volt ADC. This means that unlike the barometric
558 sensor, the output of the acceleration sensor is not ratiometric to
559 the ADC converter, and calibration is required. We also support the
560 use of any of several accelerometers from a Freescale family that
561 includes at least +/- 40g, 50g, 100g, and 200g parts. Using gravity,
562 a simple 2-point calibration yields acceptable results capturing both
563 the different sensitivities and ranges of the different accelerometer
564 parts and any variation in power supply voltages or resistor values
565 in the divider network.
567 To calibrate the acceleration sensor, use the 'c a 0' command. You
568 will be prompted to orient the board vertically with the UHF antenna
569 up and press a key, then to orient the board vertically with the
570 UHF antenna down and press a key.
571 As with all 'c' sub-commands, follow this with a 'c w' to write the
572 change to the parameter block in the on-board DataFlash chip.
574 The +1g and -1g calibration points are included in each telemetry
575 frame and are part of the header extracted by ao-dumplog after flight.
576 Note that we always store and return raw ADC samples for each
577 sensor... nothing is permanently "lost" or "damaged" if the
579 </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>
580 The big conceptual thing to realize is that you have to use a
581 TeleDongle as a programmer to update a TeleMetrum, and vice versa.
582 Due to limited memory resources in the cc1111, we don't support
583 programming either unit directly over USB.
585 You may wish to begin by ensuring you have current firmware images.
586 These are distributed as part of the AltOS software bundle that
587 also includes the AltosUI ground station program. Newer ground
588 station versions typically work fine with older firmware versions,
589 so you don't need to update your devices just to try out new
590 software features. You can always download the most recent
591 version from http://www.altusmetrum.org/AltOS/.
593 We recommend updating TeleMetrum first, before updating TeleDongle.
594 </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">
595 Find the 'programming cable' that you got as part of the starter
596 kit, that has a red 8-pin MicroMaTch connector on one end and a
597 red 4-pin MicroMaTch connector on the other end.
598 </li><li class="listitem">
599 Take the 2 screws out of the TeleDongle case to get access
600 to the circuit board.
601 </li><li class="listitem">
602 Plug the 8-pin end of the programming cable to the
603 matching connector on the TeleDongle, and the 4-pin end to the
604 matching connector on the TeleMetrum.
605 </li><li class="listitem">
606 Attach a battery to the TeleMetrum board.
607 </li><li class="listitem">
608 Plug the TeleDongle into your computer's USB port, and power
610 </li><li class="listitem">
611 Run AltosUI, and select 'Flash Image' from the File menu.
612 </li><li class="listitem">
613 Pick the TeleDongle device from the list, identifying it as the
615 </li><li class="listitem">
616 Select the image you want put on the TeleMetrum, which should have a
617 name in the form telemetrum-v1.0-0.7.1.ihx. It should be visible
618 in the default directory, if not you may have to poke around
619 your system to find it.
620 </li><li class="listitem">
621 Make sure the configuration parameters are reasonable
622 looking. If the serial number and/or RF configuration
623 values aren't right, you'll need to change them.
624 </li><li class="listitem">
625 Hit the 'OK' button and the software should proceed to flash
626 the TeleMetrum with new firmware, showing a progress bar.
627 </li><li class="listitem">
628 Confirm that the TeleMetrum board seems to have updated ok, which you
629 can do by plugging in to it over USB and using a terminal program
630 to connect to the board and issue the 'v' command to check
632 </li><li class="listitem">
633 If something goes wrong, give it another try.
634 </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>
635 Updating TeleDongle's firmware is just like updating TeleMetrum
636 firmware, but you switch which board is the programmer and which
637 is the programming target.
638 </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
639 Find the 'programming cable' that you got as part of the starter
640 kit, that has a red 8-pin MicroMaTch connector on one end and a
641 red 4-pin MicroMaTch connector on the other end.
642 </li><li class="listitem">
643 Find the USB cable that you got as part of the starter kit, and
644 plug the "mini" end in to the mating connector on TeleMetrum.
645 </li><li class="listitem">
646 Take the 2 screws out of the TeleDongle case to get access
647 to the circuit board.
648 </li><li class="listitem">
649 Plug the 8-pin end of the programming cable to the (latching)
650 matching connector on the TeleMetrum, and the 4-pin end to the
651 matching connector on the TeleDongle.
652 </li><li class="listitem">
653 Attach a battery to the TeleMetrum board.
654 </li><li class="listitem">
655 Plug both TeleMetrum and TeleDongle into your computer's USB
656 ports, and power up the TeleMetrum.
657 </li><li class="listitem">
658 Run AltosUI, and select 'Flash Image' from the File menu.
659 </li><li class="listitem">
660 Pick the TeleMongle device from the list, identifying it as the
662 </li><li class="listitem">
663 Select the image you want put on the TeleDongle, which should have a
664 name in the form teledongle-v0.2-0.7.1.ihx. It should be visible
665 in the default directory, if not you may have to poke around
666 your system to find it.
667 </li><li class="listitem">
668 Make sure the configuration parameters are reasonable
669 looking. If the serial number and/or RF configuration
670 values aren't right, you'll need to change them. The TeleDongle
671 serial number is on the "bottom" of the circuit board, and can
672 usually be read through the translucent blue plastic case without
673 needing to remove the board from the case.
674 </li><li class="listitem">
675 Hit the 'OK' button and the software should proceed to flash
676 the TeleDongle with new firmware, showing a progress bar.
677 </li><li class="listitem">
678 Confirm that the TeleDongle board seems to have updated ok, which you
679 can do by plugging in to it over USB and using a terminal program
680 to connect to the board and issue the 'v' command to check
681 the version, etc. Once you're happy, remove the programming cable
682 and put the cover back on the TeleDongle.
683 </li><li class="listitem">
684 If something goes wrong, give it another try.
686 Be careful removing the programming cable from the locking 8-pin
687 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
688 screwdriver or knife blade to gently pry the locking ears out
689 slightly to extract the connector. We used a locking connector on
690 TeleMetrum to help ensure that the cabling to companion boards
691 used in a rocket don't ever come loose accidentally in flight.
692 </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">
694 </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>
695 First off, in the US, you need an [amateur radio license](../Radio) or
696 other authorization to legally operate the radio transmitters that are part
698 </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>
699 In the rocket itself, you just need a [TeleMetrum](../TeleMetrum) board and
700 a LiPo rechargeable battery. An 860mAh battery weighs less than a 9V
701 alkaline battery, and will run a [TeleMetrum](../TeleMetrum) for hours.
703 By default, we ship TeleMetrum with a simple wire antenna. If your
704 electronics bay or the airframe it resides within is made of carbon fiber,
705 which is opaque to RF signals, you may choose to have an SMA connector
706 installed so that you can run a coaxial cable to an antenna mounted
707 elsewhere in the rocket.
708 </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>
709 To receive the data stream from the rocket, you need an antenna and short
710 feedline connected to one of our [TeleDongle](../TeleDongle) units. The
711 TeleDongle in turn plugs directly into the USB port on a notebook
712 computer. Because TeleDongle looks like a simple serial port, your computer
713 does not require special device drivers... just plug it in.
715 Right now, all of our application software is written for Linux. However,
716 because we understand that many people run Windows or MacOS, we are working
717 on a new ground station program written in Java that should work on all
720 After the flight, you can use the RF link to extract the more detailed data
721 logged in the rocket, or you can use a mini USB cable to plug into the
722 TeleMetrum board directly. Pulling out the data without having to open up
723 the rocket is pretty cool! A USB cable is also how you charge the LiPo
724 battery, so you'll want one of those anyway... the same cable used by lots
725 of digital cameras and other modern electronic stuff will work fine.
727 If your rocket lands out of sight, you may enjoy having a hand-held GPS
728 receiver, so that you can put in a waypoint for the last reported rocket
729 position before touch-down. This makes looking for your rocket a lot like
730 Geo-Cacheing... just go to the waypoint and look around starting from there.
732 You may also enjoy having a ham radio "HT" that covers the 70cm band... you
733 can use that with your antenna to direction-find the rocket on the ground
734 the same way you can use a Walston or Beeline tracker. This can be handy
735 if the rocket is hiding in sage brush or a tree, or if the last GPS position
736 doesn't get you close enough because the rocket dropped into a canyon, or
737 the wind is blowing it across a dry lake bed, or something like that... Keith
738 and Bdale both currently own and use the Yaesu VX-7R at launches.
740 So, to recap, on the ground the hardware you'll need includes:
741 </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
742 an antenna and feedline
743 </li><li class="listitem">
745 </li><li class="listitem">
747 </li><li class="listitem">
748 optionally, a handheld GPS receiver
749 </li><li class="listitem">
750 optionally, an HT or receiver covering 435 Mhz
753 The best hand-held commercial directional antennas we've found for radio
754 direction finding rockets are from
755 <a class="ulink" href="http://www.arrowantennas.com/" target="_top">
758 The 440-3 and 440-5 are both good choices for finding a
759 TeleMetrum-equipped rocket when used with a suitable 70cm HT.
760 </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>
761 Our software makes it easy to log the data from each flight, both the
762 telemetry received over the RF link during the flight itself, and the more
763 complete data log recorded in the DataFlash memory on the TeleMetrum
764 board. Once this data is on your computer, our postflight tools make it
765 easy to quickly get to the numbers everyone wants, like apogee altitude,
766 max acceleration, and max velocity. You can also generate and view a
767 standard set of plots showing the altitude, acceleration, and
768 velocity of the rocket during flight. And you can even export a data file
769 useable with Google Maps and Google Earth for visualizing the flight path
770 in two or three dimensions!
772 Our ultimate goal is to emit a set of files for each flight that can be
773 published as a web page per flight, or just viewed on your local disk with
775 </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>
776 In the future, we intend to offer "companion boards" for the rocket that will
777 plug in to TeleMetrum to collect additional data, provide more pyro channels,
778 and so forth. A reference design for a companion board will be documented
779 soon, and will be compatible with open source Arduino programming tools.
781 We are also working on the design of a hand-held ground terminal that will
782 allow monitoring the rocket's status, collecting data during flight, and
783 logging data after flight without the need for a notebook computer on the
784 flight line. Particularly since it is so difficult to read most notebook
785 screens in direct sunlight, we think this will be a great thing to have.
787 Because all of our work is open, both the hardware designs and the software,
788 if you have some great idea for an addition to the current Altus Metrum family,
789 feel free to dive in and help! Or let us know what you'd like to see that
790 we aren't already working on, and maybe we'll get excited about it too...
791 </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>
793 </h2></div></div></div><p>
795 </p></div></div></div></body></html>
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