1 <html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>The Altus Metrum System</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="The Altus Metrum System"><div class="titlepage"><div><div><h1 class="title"><a name="idm14575968"></a>The Altus Metrum System</h1></div><div><h2 class="subtitle">An Owner's Manual for TeleMetrum, TeleMini and TeleDongle Devices</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><div class="author"><h3 class="author"><span class="firstname">Bob</span> <span class="surname">Finch</span></h3></div></div><div><div class="author"><h3 class="author"><span class="firstname">Anthony</span> <span class="surname">Towns</span></h3></div></div><div><p class="copyright">Copyright © 2011 Bdale Garbee and Keith Packard</p></div><div><div class="legalnotice" title="Legal Notice"><a name="idp1689800"></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 1.0</td><td align="left">24 August 2011</td></tr><tr><td align="left" colspan="2">
8 Updated for software version 1.0. Note that 1.0 represents a
9 telemetry format change, meaning both ends of a link
10 (TeleMetrum/TeleMini and TeleDongle) must be updated or
11 communications will fail.
12 </td></tr><tr><td align="left">Revision 0.9</td><td align="left">18 January 2011</td></tr><tr><td align="left" colspan="2">
13 Updated for software version 0.9. Note that 0.9 represents a
14 telemetry format change, meaning both ends of a link (TeleMetrum and
15 TeleDongle) must be updated or communications will fail.
16 </td></tr><tr><td align="left">Revision 0.8</td><td align="left">24 November 2010</td></tr><tr><td align="left" colspan="2">Updated for software version 0.8 </td></tr></table></div></div></div><hr></div><div class="acknowledgements" title="Acknowledgements"><div class="titlepage"><div><div><h2 class="title"><a name="idp1374520"></a>Acknowledgements</h2></div></div></div>
18 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing "The
19 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
20 Kit" which formed the basis of the original Getting Started chapter
21 in this manual. Bob was one of our first customers for a production
22 TeleMetrum, and his continued enthusiasm and contributions
23 are immensely gratifying and highly appreciated!
26 And thanks to Anthony (AJ) Towns for major contributions including
27 the AltosUI graphing and site map code and associated documentation.
28 Free software means that our customers and friends can become our
29 collaborators, and we certainly appreciate this level of
33 Have fun using these products, and we hope to meet all of you
34 out on the rocket flight line somewhere.
35 </p><div class="literallayout"><p><br>
36 Bdale Garbee, KB0G<br>
37 NAR #87103, TRA #12201<br>
39 Keith Packard, KD7SQG<br>
40 NAR #88757, TRA #12200<br>
43 </div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="chapter"><a href="#idp109544">1. Introduction and Overview</a></span></dt><dt><span class="chapter"><a href="#idp112592">2. Getting Started</a></span></dt><dt><span class="chapter"><a href="#idp3558448">3. Handling Precautions</a></span></dt><dt><span class="chapter"><a href="#idp2546632">4. Hardware Overview</a></span></dt><dt><span class="chapter"><a href="#idp1232328">5. System Operation</a></span></dt><dd><dl><dt><span class="section"><a href="#idp2438160">1. Firmware Modes </a></span></dt><dt><span class="section"><a href="#idp3536616">2. GPS </a></span></dt><dt><span class="section"><a href="#idp2995920">3. Controlling An Altimeter Over The Radio Link</a></span></dt><dt><span class="section"><a href="#idp2636120">4. Ground Testing </a></span></dt><dt><span class="section"><a href="#idp2215712">5. Radio Link </a></span></dt><dt><span class="section"><a href="#idp2588328">6. Configurable Parameters</a></span></dt><dd><dl><dt><span class="section"><a href="#idp3166536">6.1. Radio Frequency</a></span></dt><dt><span class="section"><a href="#idp1269376">6.2. Apogee Delay</a></span></dt><dt><span class="section"><a href="#idp1443480">6.3. Main Deployment Altitude</a></span></dt><dt><span class="section"><a href="#idp3505904">6.4. Maximum Flight Log</a></span></dt><dt><span class="section"><a href="#idp3167664">6.5. Ignite Mode</a></span></dt><dt><span class="section"><a href="#idp1494808">6.6. Pad Orientation</a></span></dt></dl></dd></dl></dd><dt><span class="chapter"><a href="#idp2062320">6. AltosUI</a></span></dt><dd><dl><dt><span class="section"><a href="#idp2011040">1. Monitor Flight</a></span></dt><dd><dl><dt><span class="section"><a href="#idp1611184">1.1. Launch Pad</a></span></dt><dt><span class="section"><a href="#idp2194832">1.2. Ascent</a></span></dt><dt><span class="section"><a href="#idp3351928">1.3. Descent</a></span></dt><dt><span class="section"><a href="#idp1234032">1.4. Landed</a></span></dt><dt><span class="section"><a href="#idp3388472">1.5. Site Map</a></span></dt></dl></dd><dt><span class="section"><a href="#idp1930856">2. Save Flight Data</a></span></dt><dt><span class="section"><a href="#idp3546840">3. Replay Flight</a></span></dt><dt><span class="section"><a href="#idp3331568">4. Graph Data</a></span></dt><dt><span class="section"><a href="#idp1385704">5. Export Data</a></span></dt><dd><dl><dt><span class="section"><a href="#idp3437744">5.1. Comma Separated Value Format</a></span></dt><dt><span class="section"><a href="#idp2912584">5.2. Keyhole Markup Language (for Google Earth)</a></span></dt></dl></dd><dt><span class="section"><a href="#idp2438432">6. Configure Altimeter</a></span></dt><dd><dl><dt><span class="section"><a href="#idp3551544">6.1. Main Deploy Altitude</a></span></dt><dt><span class="section"><a href="#idp2848008">6.2. Apogee Delay</a></span></dt><dt><span class="section"><a href="#idp3459616">6.3. Radio Frequency</a></span></dt><dt><span class="section"><a href="#idp2329488">6.4. Radio Calibration</a></span></dt><dt><span class="section"><a href="#idp3507216">6.5. Callsign</a></span></dt><dt><span class="section"><a href="#idp1223488">6.6. Maximum Flight Log Size</a></span></dt><dt><span class="section"><a href="#idp3489504">6.7. Ignite Mode</a></span></dt><dt><span class="section"><a href="#idp1526824">6.8. Pad Orientation</a></span></dt></dl></dd><dt><span class="section"><a href="#idp2433504">7. Configure AltosUI</a></span></dt><dd><dl><dt><span class="section"><a href="#idp3510984">7.1. Voice Settings</a></span></dt><dt><span class="section"><a href="#idp2029264">7.2. Log Directory</a></span></dt><dt><span class="section"><a href="#idp2350072">7.3. Callsign</a></span></dt><dt><span class="section"><a href="#idp2694528">7.4. Font Size</a></span></dt><dt><span class="section"><a href="#idp1856992">7.5. Serial Debug</a></span></dt><dt><span class="section"><a href="#idp1891664">7.6. Manage Frequencies</a></span></dt></dl></dd><dt><span class="section"><a href="#idp3058032">8. Flash Image</a></span></dt><dt><span class="section"><a href="#idp3184648">9. Fire Igniter</a></span></dt><dt><span class="section"><a href="#idp1519784">10. Scan Channels</a></span></dt><dt><span class="section"><a href="#idp2057448">11. Load Maps</a></span></dt><dt><span class="section"><a href="#idp1472424">12. Monitor Idle</a></span></dt></dl></dd><dt><span class="chapter"><a href="#idp3231728">7. Using Altus Metrum Products</a></span></dt><dd><dl><dt><span class="section"><a href="#idp2024456">1. Being Legal</a></span></dt><dt><span class="section"><a href="#idp2425408">2. In the Rocket</a></span></dt><dt><span class="section"><a href="#idp2236704">3. On the Ground</a></span></dt><dt><span class="section"><a href="#idp2243664">4. Data Analysis</a></span></dt><dt><span class="section"><a href="#idp2104880">5. Future Plans</a></span></dt></dl></dd><dt><span class="chapter"><a href="#idp3340600">8. Altimeter Installation Recommendations</a></span></dt><dd><dl><dt><span class="section"><a href="#idp3522016">1. Mounting the Altimeter</a></span></dt><dt><span class="section"><a href="#idp2062944">2. Dealing with the Antenna</a></span></dt><dt><span class="section"><a href="#idp2075472">3. Preserving GPS Reception</a></span></dt><dt><span class="section"><a href="#idp1887864">4. Radio Frequency Interference</a></span></dt><dt><span class="section"><a href="#idp2902592">5. The Barometric Sensor</a></span></dt><dt><span class="section"><a href="#idp2991488">6. Ground Testing</a></span></dt></dl></dd><dt><span class="chapter"><a href="#idp2336184">9. Updating Device Firmware</a></span></dt><dd><dl><dt><span class="section"><a href="#idp3061016">1. Updating TeleMetrum Firmware</a></span></dt><dt><span class="section"><a href="#idp1980776">2. Updating TeleMini Firmware</a></span></dt><dt><span class="section"><a href="#idp2731488">3. Updating TeleDongle Firmware</a></span></dt></dl></dd><dt><span class="chapter"><a href="#idp2742616">10. Hardware Specifications</a></span></dt><dd><dl><dt><span class="section"><a href="#idp3450088">1. TeleMetrum Specifications</a></span></dt><dt><span class="section"><a href="#idp2397848">2. TeleMini Specifications</a></span></dt></dl></dd><dt><span class="chapter"><a href="#idp3517088">11. FAQ</a></span></dt><dt><span class="appendix"><a href="#idp2358816">A. Notes for Older Software</a></span></dt><dt><span class="appendix"><a href="#idp2555760">B. Calibration</a></span></dt><dd><dl><dt><span class="section"><a href="#idp1119368">1. Radio Frequency</a></span></dt><dt><span class="section"><a href="#idp3257080">2. TeleMetrum Accelerometer</a></span></dt></dl></dd><dt><span class="appendix"><a href="#idp2653672">C. Release Notes</a></span></dt></dl></div><div class="chapter" title="Chapter 1. Introduction and Overview"><div class="titlepage"><div><div><h2 class="title"><a name="idp109544"></a>Chapter 1. Introduction and Overview</h2></div></div></div><p>
44 Welcome to the Altus Metrum community! Our circuits and software reflect
45 our passion for both hobby rocketry and Free Software. We hope their
46 capabilities and performance will delight you in every way, but by
47 releasing all of our hardware and software designs under open licenses,
48 we also hope to empower you to take as active a role in our collective
51 The first device created for our community was TeleMetrum, a dual
52 deploy altimeter with fully integrated GPS and radio telemetry
53 as standard features, and a "companion interface" that will
54 support optional capabilities in the future.
56 The newest device is TeleMini, a dual deploy altimeter with
57 radio telemetry and radio direction finding. This device is only
58 13mm by 38mm (½ inch by 1½ inches) and can fit easily in an 18mm
61 Complementing TeleMetrum and TeleMini is TeleDongle, a USB to RF
62 interface for communicating with the altimeters. Combined with your
64 notebook computer, TeleDongle and our associated user interface software
65 form a complete ground station capable of logging and displaying in-flight
66 telemetry, aiding rocket recovery, then processing and archiving flight
67 data for analysis and review.
69 More products will be added to the Altus Metrum family over time, and
70 we currently envision that this will be a single, comprehensive manual
71 for the entire product family.
72 </p></div><div class="chapter" title="Chapter 2. Getting Started"><div class="titlepage"><div><div><h2 class="title"><a name="idp112592"></a>Chapter 2. Getting Started</h2></div></div></div><p>
73 The first thing to do after you check the inventory of parts in your
74 "starter kit" is to charge the battery.
76 The TeleMetrum battery can be charged by plugging it into the
77 corresponding socket of the TeleMetrum and then using the USB A to
79 cable to plug the TeleMetrum into your computer's USB socket. The
80 TeleMetrum circuitry will charge the battery whenever it is plugged
81 in, because the TeleMetrum's on-off switch does NOT control the
84 When the GPS chip is initially searching for
85 satellites, TeleMetrum will consume more current than it can pull
86 from the USB port, so the battery must be attached in order to get
87 satellite lock. Once GPS is locked, the current consumption goes back
88 down enough to enable charging while
89 running. So it's a good idea to fully charge the battery as your
90 first item of business so there is no issue getting and maintaining
91 satellite lock. The yellow charge indicator led will go out when the
92 battery is nearly full and the charger goes to trickle charge. It
93 can take several hours to fully recharge a deeply discharged battery.
95 The TeleMini battery can be charged by disconnecting it from the
96 TeleMini board and plugging it into a standalone battery charger
97 board, and connecting that via a USB cable to a laptop or other USB
100 The other active device in the starter kit is the TeleDongle USB to
101 RF interface. If you plug it in to your Mac or Linux computer it should
102 "just work", showing up as a serial port device. Windows systems need
103 driver information that is part of the AltOS download to know that the
104 existing USB modem driver will work. We therefore recommend installing
105 our software before plugging in TeleDongle if you are using a Windows
106 computer. If you are using Linux and are having problems, try moving
107 to a fresher kernel (2.6.33 or newer), as the USB serial driver had
108 ugly bugs in some earlier versions.
110 Next you should obtain and install the AltOS software. These include
111 the AltosUI ground station program, current firmware images for
112 TeleMetrum, TeleMini and TeleDongle, and a number of standalone
113 utilities that are rarely needed. Pre-built binary packages are
114 available for Linux, Microsoft Windows, and recent MacOSX versions.
115 Full source code and build instructions are also available.
116 The latest version may always be downloaded from
117 <a class="ulink" href="http://altusmetrum.org/AltOS" target="_top">http://altusmetrum.org/AltOS</a>.
118 </p></div><div class="chapter" title="Chapter 3. Handling Precautions"><div class="titlepage"><div><div><h2 class="title"><a name="idp3558448"></a>Chapter 3. Handling Precautions</h2></div></div></div><p>
119 All Altus Metrum products are sophisticated electronic devices.
120 When handled gently and properly installed in an air-frame, they
121 will deliver impressive results. However, as with all electronic
122 devices, there are some precautions you must take.
124 The Lithium Polymer rechargeable batteries have an
125 extraordinary power density. This is great because we can fly with
126 much less battery mass than if we used alkaline batteries or previous
127 generation rechargeable batteries... but if they are punctured
128 or their leads are allowed to short, they can and will release their
130 Thus we recommend that you take some care when handling our batteries
131 and consider giving them some extra protection in your air-frame. We
132 often wrap them in suitable scraps of closed-cell packing foam before
133 strapping them down, for example.
135 The barometric sensors used on both TeleMetrum and TeleMini are
136 sensitive to sunlight. In normal TeleMetrum mounting situations, it
137 and all of the other surface mount components
138 are "down" towards whatever the underlying mounting surface is, so
139 this is not normally a problem. Please consider this, though, when
140 designing an installation, for example, in an air-frame with a
141 see-through plastic payload bay. It is particularly important to
142 consider this with TeleMini, both because the baro sensor is on the
143 "top" of the board, and because many model rockets with payload bays
144 use clear plastic for the payload bay! Replacing these with an opaque
145 cardboard tube, painting them, or wrapping them with a layer of masking
146 tape are all reasonable approaches to keep the sensor out of direct
149 The barometric sensor sampling port must be able to "breathe",
150 both by not being covered by foam or tape or other materials that might
151 directly block the hole on the top of the sensor, and also by having a
152 suitable static vent to outside air.
154 As with all other rocketry electronics, Altus Metrum altimeters must
155 be protected from exposure to corrosive motor exhaust and ejection
157 </p></div><div class="chapter" title="Chapter 4. Hardware Overview"><div class="titlepage"><div><div><h2 class="title"><a name="idp2546632"></a>Chapter 4. Hardware Overview</h2></div></div></div><p>
158 TeleMetrum is a 1 inch by 2.75 inch circuit board. It was designed to
159 fit inside coupler for 29mm air-frame tubing, but using it in a tube that
160 small in diameter may require some creativity in mounting and wiring
161 to succeed! The presence of an accelerometer means TeleMetrum should
162 be aligned along the flight axis of the airframe, and by default the 1/4
163 wave UHF wire antenna should be on the nose-cone end of the board. The
164 antenna wire is about 7 inches long, and wiring for a power switch and
165 the e-matches for apogee and main ejection charges depart from the
166 fin can end of the board, meaning an ideal "simple" avionics
167 bay for TeleMetrum should have at least 10 inches of interior length.
169 TeleMini is a 0.5 inch by 1.5 inch circuit board. It was designed to
170 fit inside an 18mm air-frame tube, but using it in a tube that
171 small in diameter may require some creativity in mounting and wiring
172 to succeed! Since there is no accelerometer, TeleMini can be mounted
173 in any convenient orientation. The default 1/4
174 wave UHF wire antenna attached to the center of one end of
175 the board is about 7 inches long, and wiring for a power switch and
176 the e-matches for apogee and main ejection charges depart from the
177 other end of the board, meaning an ideal "simple" avionics
178 bay for TeleMini should have at least 9 inches of interior length.
180 A typical TeleMetrum or TeleMini installation involves attaching
181 only a suitable Lithium Polymer battery, a single pole switch for
182 power on/off, and two pairs of wires connecting e-matches for the
183 apogee and main ejection charges.
185 By default, we use the unregulated output of the Li-Po battery directly
186 to fire ejection charges. This works marvelously with standard
187 low-current e-matches like the J-Tek from MJG Technologies, and with
188 Quest Q2G2 igniters. However, if you want or need to use a separate
189 pyro battery, check out the "External Pyro Battery" section in this
190 manual for instructions on how to wire that up. The altimeters are
191 designed to work with an external pyro battery of no more than 15 volts.
193 Ejection charges are wired directly to the screw terminal block
194 at the aft end of the altimeter. You'll need a very small straight
195 blade screwdriver for these screws, such as you might find in a
196 jeweler's screwdriver set.
198 TeleMetrum also uses the screw terminal block for the power
199 switch leads. On TeleMini, the power switch leads are soldered
200 directly to the board and can be connected directly to a switch.
202 For most air-frames, the integrated antennas are more than
203 adequate. However, if you are installing in a carbon-fiber or
204 metal electronics bay which is opaque to RF signals, you may need to
205 use off-board external antennas instead. In this case, you can
206 order an altimeter with an SMA connector for the UHF antenna
207 connection, and, on TeleMetrum, you can unplug the integrated GPS
208 antenna and select an appropriate off-board GPS antenna with
209 cable terminating in a U.FL connector.
210 </p></div><div class="chapter" title="Chapter 5. System Operation"><div class="titlepage"><div><div><h2 class="title"><a name="idp1232328"></a>Chapter 5. System Operation</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#idp2438160">1. Firmware Modes </a></span></dt><dt><span class="section"><a href="#idp3536616">2. GPS </a></span></dt><dt><span class="section"><a href="#idp2995920">3. Controlling An Altimeter Over The Radio Link</a></span></dt><dt><span class="section"><a href="#idp2636120">4. Ground Testing </a></span></dt><dt><span class="section"><a href="#idp2215712">5. Radio Link </a></span></dt><dt><span class="section"><a href="#idp2588328">6. Configurable Parameters</a></span></dt><dd><dl><dt><span class="section"><a href="#idp3166536">6.1. Radio Frequency</a></span></dt><dt><span class="section"><a href="#idp1269376">6.2. Apogee Delay</a></span></dt><dt><span class="section"><a href="#idp1443480">6.3. Main Deployment Altitude</a></span></dt><dt><span class="section"><a href="#idp3505904">6.4. Maximum Flight Log</a></span></dt><dt><span class="section"><a href="#idp3167664">6.5. Ignite Mode</a></span></dt><dt><span class="section"><a href="#idp1494808">6.6. Pad Orientation</a></span></dt></dl></dd></dl></div><div class="section" title="1. Firmware Modes"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp2438160"></a>1. Firmware Modes </h2></div></div></div><p>
211 The AltOS firmware build for the altimeters has two
212 fundamental modes, "idle" and "flight". Which of these modes
213 the firmware operates in is determined at start up time. For
214 TeleMetrum, the mode is controlled by the orientation of the
215 rocket (well, actually the board, of course...) at the time
216 power is switched on. If the rocket is "nose up", then
217 TeleMetrum assumes it's on a rail or rod being prepared for
218 launch, so the firmware chooses flight mode. However, if the
219 rocket is more or less horizontal, the firmware instead enters
220 idle mode. Since TeleMini doesn't have an accelerometer we can
221 use to determine orientation, "idle" mode is selected when the
222 board receives a command packet within the first five seconds
223 of operation; if no packet is received, the board enters
226 At power on, you will hear three beeps or see three flashes
227 ("S" in Morse code for start up) and then a pause while
228 the altimeter completes initialization and self test, and decides
229 which mode to enter next.
231 In flight or "pad" mode, the altimeter engages the flight
232 state machine, goes into transmit-only mode to
233 send telemetry, and waits for launch to be detected.
234 Flight mode is indicated by an "di-dah-dah-dit" ("P" for pad)
235 on the beeper or lights, followed by beeps or flashes
236 indicating the state of the pyrotechnic igniter continuity.
237 One beep/flash indicates apogee continuity, two beeps/flashes
238 indicate main continuity, three beeps/flashes indicate both
239 apogee and main continuity, and one longer "brap" sound or
240 rapidly alternating lights indicates no continuity. For a
241 dual deploy flight, make sure you're getting three beeps or
242 flashes before launching! For apogee-only or motor eject
243 flights, do what makes sense.
245 If idle mode is entered, you will hear an audible "di-dit" or see
246 two short flashes ("I" for idle), and the flight state machine is
247 disengaged, thus no ejection charges will fire. The altimeters also
248 listen for the radio link when in idle mode for requests sent via
249 TeleDongle. Commands can be issued to a TeleMetrum in idle mode
251 USB or the radio link equivalently. TeleMini only has the radio link.
252 Idle mode is useful for configuring the altimeter, for extracting data
253 from the on-board storage chip after flight, and for ground testing
256 One "neat trick" of particular value when TeleMetrum is used with
257 very large air-frames, is that you can power the board up while the
258 rocket is horizontal, such that it comes up in idle mode. Then you can
259 raise the air-frame to launch position, and issue a 'reset' command
260 via TeleDongle over the radio link to cause the altimeter to reboot and
261 come up in flight mode. This is much safer than standing on the top
262 step of a rickety step-ladder or hanging off the side of a launch
263 tower with a screw-driver trying to turn on your avionics before
265 </p></div><div class="section" title="2. GPS"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp3536616"></a>2. GPS </h2></div></div></div><p>
266 TeleMetrum includes a complete GPS receiver. A complete explanation
267 of how GPS works is beyond the scope of this manual, but the bottom
268 line is that the TeleMetrum GPS receiver needs to lock onto at least
269 four satellites to obtain a solid 3 dimensional position fix and know
272 TeleMetrum provides backup power to the GPS chip any time a
273 battery is connected. This allows the receiver to "warm start" on
274 the launch rail much faster than if every power-on were a GPS
275 "cold start". In typical operations, powering up TeleMetrum
276 on the flight line in idle mode while performing final air-frame
277 preparation will be sufficient to allow the GPS receiver to cold
278 start and acquire lock. Then the board can be powered down during
279 RSO review and installation on a launch rod or rail. When the board
280 is turned back on, the GPS system should lock very quickly, typically
281 long before igniter installation and return to the flight line are
283 </p></div><div class="section" title="3. Controlling An Altimeter Over The Radio Link"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp2995920"></a>3. Controlling An Altimeter Over The Radio Link</h2></div></div></div><p>
284 One of the unique features of the Altus Metrum system is
285 the ability to create a two way command link between TeleDongle
286 and an altimeter using the digital radio transceivers built into
287 each device. This allows you to interact with the altimeter from
288 afar, as if it were directly connected to the computer.
290 Any operation which can be performed with TeleMetrum can
291 either be done with TeleMetrum directly connected to the
292 computer via the USB cable, or through the radio
293 link. TeleMini doesn't provide a USB connector and so it is
294 always communicated with over radio. Select the appropriate
295 TeleDongle device when the list of devices is presented and
296 AltosUI will interact with an altimeter over the radio link.
298 One oddity in the current interface is how AltosUI selects the
299 frequency for radio communications. Instead of providing
300 an interface to specifically configure the frequency, it uses
301 whatever frequency was most recently selected for the target
302 TeleDongle device in Monitor Flight mode. If you haven't ever
303 used that mode with the TeleDongle in question, select the
304 Monitor Flight button from the top level UI, and pick the
305 appropriate TeleDongle device. Once the flight monitoring
306 window is open, select the desired frequency and then close it
307 down again. All radio communications will now use that frequency.
308 </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>
309 Save Flight Data—Recover flight data from the rocket without
311 </p></li><li class="listitem"><p>
312 Configure altimeter apogee delays or main deploy heights
313 to respond to changing launch conditions. You can also
314 'reboot' the altimeter. Use this to remotely enable the
315 flight computer by turning TeleMetrum on in "idle" mode,
316 then once the air-frame is oriented for launch, you can
317 reboot the altimeter and have it restart in pad mode
318 without having to climb the scary ladder.
319 </p></li><li class="listitem"><p>
320 Fire Igniters—Test your deployment charges without snaking
321 wires out through holes in the air-frame. Simply assembly the
322 rocket as if for flight with the apogee and main charges
323 loaded, then remotely command the altimeter to fire the
325 </p></li></ul></div><p>
326 Operation over the radio link for configuring an altimeter, ground
327 testing igniters, and so forth uses the same RF frequencies as flight
328 telemetry. To configure the desired TeleDongle frequency, select
329 the monitor flight tab, then use the frequency selector and
330 close the window before performing other desired radio operations.
332 TeleMetrum only enables radio commanding in 'idle' mode, so
333 make sure you have TeleMetrum lying horizontally when you turn
334 it on. Otherwise, TeleMetrum will start in 'pad' mode ready for
335 flight, and will not be listening for command packets from TeleDongle.
337 TeleMini listens for a command packet for five seconds after
338 first being turned on, if it doesn't hear anything, it enters
339 'pad' mode, ready for flight and will no longer listen for
340 command packets. The easiest way to connect to TeleMini is to
341 initiate the command and select the TeleDongle device. At this
342 point, the TeleDongle will be attempting to communicate with
343 the TeleMini. Now turn TeleMini on, and it should immediately
344 start communicating with the TeleDongle and the desired
345 operation can be performed.
347 You can monitor the operation of the radio link by watching the
348 lights on the devices. The red LED will flash each time a packet
349 is tramsitted, while the green LED will light up on TeleDongle when
350 it is waiting to receive a packet from the altimeter.
351 </p></div><div class="section" title="4. Ground Testing"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp2636120"></a>4. Ground Testing </h2></div></div></div><p>
352 An important aspect of preparing a rocket using electronic deployment
353 for flight is ground testing the recovery system. Thanks
354 to the bi-directional radio link central to the Altus Metrum system,
355 this can be accomplished in a TeleMetrum or TeleMini equipped rocket
356 with less work than you may be accustomed to with other systems. It
359 Just prep the rocket for flight, then power up the altimeter
360 in "idle" mode (placing air-frame horizontal for TeleMetrum or
361 selected the Configure Altimeter tab for TeleMini). This will cause
362 the firmware to go into "idle" mode, in which the normal flight
363 state machine is disabled and charges will not fire without
364 manual command. You can now command the altimeter to fire the apogee
365 or main charges from a safe distance using your computer and
366 TeleDongle and the Fire Igniter tab to complete ejection testing.
367 </p></div><div class="section" title="5. Radio Link"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp2215712"></a>5. Radio Link </h2></div></div></div><p>
368 The chip our boards are based on incorporates an RF transceiver, but
369 it's not a full duplex system... each end can only be transmitting or
370 receiving at any given moment. So we had to decide how to manage the
373 By design, the altimeter firmware listens for the radio link when
374 it's in "idle mode", which
375 allows us to use the radio link to configure the rocket, do things like
376 ejection tests, and extract data after a flight without having to
377 crack open the air-frame. However, when the board is in "flight
378 mode", the altimeter only
379 transmits and doesn't listen at all. That's because we want to put
380 ultimate priority on event detection and getting telemetry out of
382 the radio in case the rocket crashes and we aren't able to extract
385 We don't use a 'normal packet radio' mode like APRS because they're
386 just too inefficient. The GFSK modulation we use is FSK with the
387 base-band pulses passed through a
388 Gaussian filter before they go into the modulator to limit the
389 transmitted bandwidth. When combined with the hardware forward error
390 correction support in the cc1111 chip, this allows us to have a very
391 robust 38.4 kilobit data link with only 10 milliwatts of transmit
392 power, a whip antenna in the rocket, and a hand-held Yagi on the
393 ground. We've had flights to above 21k feet AGL with great reception,
394 and calculations suggest we should be good to well over 40k feet AGL
395 with a 5-element yagi on the ground. We hope to fly boards to higher
396 altitudes over time, and would of course appreciate customer feedback
397 on performance in higher altitude flights!
398 </p></div><div class="section" title="6. Configurable Parameters"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp2588328"></a>6. Configurable Parameters</h2></div></div></div><p>
399 Configuring an Altus Metrum altimeter for flight is very
400 simple. Even on our baro-only TeleMini board, the use of a Kalman
401 filter means there is no need to set a "mach delay". The few
402 configurable parameters can all be set using AltosUI over USB or
403 or radio link via TeleDongle.
404 </p><div class="section" title="6.1. Radio Frequency"><div class="titlepage"><div><div><h3 class="title"><a name="idp3166536"></a>6.1. Radio Frequency</h3></div></div></div><p>
405 Altus Metrum boards support radio frequencies in the 70cm
406 band. By default, the configuration interface provides a
407 list of 10 "standard" frequencies in 100kHz channels starting at
408 434.550MHz. However, the firmware supports use of
409 any 50kHz multiple within the 70cm band. At any given
410 launch, we highly recommend coordinating when and by whom each
411 frequency will be used to avoid interference. And of course, both
412 altimeter and TeleDongle must be configured to the same
413 frequency to successfully communicate with each other.
414 </p></div><div class="section" title="6.2. Apogee Delay"><div class="titlepage"><div><div><h3 class="title"><a name="idp1269376"></a>6.2. Apogee Delay</h3></div></div></div><p>
415 Apogee delay is the number of seconds after the altimeter detects flight
416 apogee that the drogue charge should be fired. In most cases, this
417 should be left at the default of 0. However, if you are flying
418 redundant electronics such as for an L3 certification, you may wish
419 to set one of your altimeters to a positive delay so that both
420 primary and backup pyrotechnic charges do not fire simultaneously.
422 The Altus Metrum apogee detection algorithm fires exactly at
423 apogee. If you are also flying an altimeter like the
424 PerfectFlite MAWD, which only supports selecting 0 or 1
425 seconds of apogee delay, you may wish to set the MAWD to 0
426 seconds delay and set the TeleMetrum to fire your backup 2
427 or 3 seconds later to avoid any chance of both charges
428 firing simultaneously. We've flown several air-frames this
429 way quite happily, including Keith's successful L3 cert.
430 </p></div><div class="section" title="6.3. Main Deployment Altitude"><div class="titlepage"><div><div><h3 class="title"><a name="idp1443480"></a>6.3. Main Deployment Altitude</h3></div></div></div><p>
431 By default, the altimeter will fire the main deployment charge at an
432 elevation of 250 meters (about 820 feet) above ground. We think this
433 is a good elevation for most air-frames, but feel free to change this
434 to suit. In particular, if you are flying two altimeters, you may
436 deployment elevation for the backup altimeter to be something lower
437 than the primary so that both pyrotechnic charges don't fire
439 </p></div><div class="section" title="6.4. Maximum Flight Log"><div class="titlepage"><div><div><h3 class="title"><a name="idp3505904"></a>6.4. Maximum Flight Log</h3></div></div></div><p>
440 TeleMetrum version 1.1 has 2MB of on-board flash storage,
441 enough to hold over 40 minutes of data at full data rate
442 (100 samples/second). TeleMetrum 1.0 has 1MB of on-board
443 storage. As data are stored at a reduced rate during descent
444 (10 samples/second), there's plenty of space to store many
445 flights worth of data.
447 The on-board flash is partitioned into separate flight logs,
448 each of a fixed maximum size. Increase the maximum size of
449 each log and you reduce the number of flights that can be
450 stored. Decrease the size and TeleMetrum can store more
453 All of the configuration data is also stored in the flash
454 memory, which consumes 64kB on TeleMetrum v1.1 and 256B on
455 TeleMetrum v1.0. This configuration space is not available
456 for storing flight log data.
458 To compute the amount of space needed for a single flight,
459 you can multiply the expected ascent time (in seconds) by
460 800, multiply the expected descent time (in seconds) by 80
461 and add the two together. That will slightly under-estimate
462 the storage (in bytes) needed for the flight. For instance,
463 a flight spending 20 seconds in ascent and 150 seconds in
464 descent will take about (20 * 800) + (150 * 80) = 28000
465 bytes of storage. You could store dozens of these flights in
468 The default size, 192kB, allows for 10 flights of storage on
469 TeleMetrum v1.1 and 5 flights on TeleMetrum v1.0. This
470 ensures that you won't need to erase the memory before
471 flying each time while still allowing more than sufficient
472 storage for each flight.
474 As TeleMini does not contain an accelerometer, it stores
475 data at 10 samples per second during ascent and one sample
476 per second during descent. Each sample is a two byte reading
477 from the barometer. These are stored in 5kB of
478 on-chip flash memory which can hold 256 seconds at the
479 ascent rate or 2560 seconds at the descent rate. Because of
480 the limited storage, TeleMini cannot hold data for more than
481 one flight, and so must be erased after each flight or it
482 will not capture data for subsequent flights.
483 </p></div><div class="section" title="6.5. Ignite Mode"><div class="titlepage"><div><div><h3 class="title"><a name="idp3167664"></a>6.5. Ignite Mode</h3></div></div></div><p>
484 Instead of firing one charge at apogee and another charge at
485 a fixed height above the ground, you can configure the
486 altimeter to fire both at apogee or both during
487 descent. This was added to support an airframe that has two
488 TeleMetrum computers, one in the fin can and one in the
491 Providing the ability to use both igniters for apogee or
492 main allows some level of redundancy without needing two
493 flight computers. In Redundant Apogee or Redundant Main
494 mode, the two charges will be fired two seconds apart.
495 </p></div><div class="section" title="6.6. Pad Orientation"><div class="titlepage"><div><div><h3 class="title"><a name="idp1494808"></a>6.6. Pad Orientation</h3></div></div></div><p>
496 TeleMetrum measures acceleration along the axis of the
497 board. Which way the board is oriented affects the sign of
498 the acceleration value. Instead of trying to guess which way
499 the board is mounted in the air frame, TeleMetrum must be
500 explicitly configured for either Antenna Up or Antenna
501 Down. The default, Antenna Up, expects the end of the
502 TeleMetrum board connected to the 70cm antenna to be nearest
503 the nose of the rocket, with the end containing the screw
504 terminals nearest the tail.
505 </p></div></div></div><div class="chapter" title="Chapter 6. AltosUI"><div class="titlepage"><div><div><h2 class="title"><a name="idp2062320"></a>Chapter 6. AltosUI</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#idp2011040">1. Monitor Flight</a></span></dt><dd><dl><dt><span class="section"><a href="#idp1611184">1.1. Launch Pad</a></span></dt><dt><span class="section"><a href="#idp2194832">1.2. Ascent</a></span></dt><dt><span class="section"><a href="#idp3351928">1.3. Descent</a></span></dt><dt><span class="section"><a href="#idp1234032">1.4. Landed</a></span></dt><dt><span class="section"><a href="#idp3388472">1.5. Site Map</a></span></dt></dl></dd><dt><span class="section"><a href="#idp1930856">2. Save Flight Data</a></span></dt><dt><span class="section"><a href="#idp3546840">3. Replay Flight</a></span></dt><dt><span class="section"><a href="#idp3331568">4. Graph Data</a></span></dt><dt><span class="section"><a href="#idp1385704">5. Export Data</a></span></dt><dd><dl><dt><span class="section"><a href="#idp3437744">5.1. Comma Separated Value Format</a></span></dt><dt><span class="section"><a href="#idp2912584">5.2. Keyhole Markup Language (for Google Earth)</a></span></dt></dl></dd><dt><span class="section"><a href="#idp2438432">6. Configure Altimeter</a></span></dt><dd><dl><dt><span class="section"><a href="#idp3551544">6.1. Main Deploy Altitude</a></span></dt><dt><span class="section"><a href="#idp2848008">6.2. Apogee Delay</a></span></dt><dt><span class="section"><a href="#idp3459616">6.3. Radio Frequency</a></span></dt><dt><span class="section"><a href="#idp2329488">6.4. Radio Calibration</a></span></dt><dt><span class="section"><a href="#idp3507216">6.5. Callsign</a></span></dt><dt><span class="section"><a href="#idp1223488">6.6. Maximum Flight Log Size</a></span></dt><dt><span class="section"><a href="#idp3489504">6.7. Ignite Mode</a></span></dt><dt><span class="section"><a href="#idp1526824">6.8. Pad Orientation</a></span></dt></dl></dd><dt><span class="section"><a href="#idp2433504">7. Configure AltosUI</a></span></dt><dd><dl><dt><span class="section"><a href="#idp3510984">7.1. Voice Settings</a></span></dt><dt><span class="section"><a href="#idp2029264">7.2. Log Directory</a></span></dt><dt><span class="section"><a href="#idp2350072">7.3. Callsign</a></span></dt><dt><span class="section"><a href="#idp2694528">7.4. Font Size</a></span></dt><dt><span class="section"><a href="#idp1856992">7.5. Serial Debug</a></span></dt><dt><span class="section"><a href="#idp1891664">7.6. Manage Frequencies</a></span></dt></dl></dd><dt><span class="section"><a href="#idp3058032">8. Flash Image</a></span></dt><dt><span class="section"><a href="#idp3184648">9. Fire Igniter</a></span></dt><dt><span class="section"><a href="#idp1519784">10. Scan Channels</a></span></dt><dt><span class="section"><a href="#idp2057448">11. Load Maps</a></span></dt><dt><span class="section"><a href="#idp1472424">12. Monitor Idle</a></span></dt></dl></div><p>
506 The AltosUI program provides a graphical user interface for
507 interacting with the Altus Metrum product family, including
508 TeleMetrum, TeleMini and TeleDongle. AltosUI can monitor telemetry data,
509 configure TeleMetrum, TeleMini and TeleDongle devices and many other
510 tasks. The primary interface window provides a selection of
511 buttons, one for each major activity in the system. This manual
512 is split into chapters, each of which documents one of the tasks
513 provided from the top-level toolbar.
514 </p><div class="section" title="1. Monitor Flight"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp2011040"></a>1. Monitor Flight</h2></div><div><h3 class="subtitle">Receive, Record and Display Telemetry Data</h3></div></div></div><p>
515 Selecting this item brings up a dialog box listing all of the
516 connected TeleDongle devices. When you choose one of these,
517 AltosUI will create a window to display telemetry data as
518 received by the selected TeleDongle device.
520 All telemetry data received are automatically recorded in
521 suitable log files. The name of the files includes the current
522 date and rocket serial and flight numbers.
524 The radio frequency being monitored by the TeleDongle device is
525 displayed at the top of the window. You can configure the
526 frequency by clicking on the frequency box and selecting the desired
527 frequency. AltosUI remembers the last frequency selected for each
528 TeleDongle and selects that automatically the next time you use
531 Below the TeleDongle frequency selector, the window contains a few
532 significant pieces of information about the altimeter providing
533 the telemetry data stream:
534 </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>The configured call-sign</p></li><li class="listitem"><p>The device serial number</p></li><li class="listitem"><p>The flight number. Each altimeter remembers how many
536 </p></li><li class="listitem"><p>
537 The rocket flight state. Each flight passes through several
538 states including Pad, Boost, Fast, Coast, Drogue, Main and
540 </p></li><li class="listitem"><p>
541 The Received Signal Strength Indicator value. This lets
542 you know how strong a signal TeleDongle is receiving. The
543 radio inside TeleDongle operates down to about -99dBm;
544 weaker signals may not be receivable. The packet link uses
545 error detection and correction techniques which prevent
546 incorrect data from being reported.
547 </p></li></ul></div><p>
548 Finally, the largest portion of the window contains a set of
549 tabs, each of which contain some information about the rocket.
550 They're arranged in 'flight order' so that as the flight
551 progresses, the selected tab automatically switches to display
552 data relevant to the current state of the flight. You can select
553 other tabs at any time. The final 'table' tab displays all of
554 the raw telemetry values in one place in a spreadsheet-like format.
555 </p><div class="section" title="1.1. Launch Pad"><div class="titlepage"><div><div><h3 class="title"><a name="idp1611184"></a>1.1. Launch Pad</h3></div></div></div><p>
556 The 'Launch Pad' tab shows information used to decide when the
557 rocket is ready for flight. The first elements include red/green
558 indicators, if any of these is red, you'll want to evaluate
559 whether the rocket is ready to launch:
560 </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>
561 Battery Voltage. This indicates whether the Li-Po battery
562 powering the TeleMetrum has sufficient charge to last for
563 the duration of the flight. A value of more than
564 3.7V is required for a 'GO' status.
565 </p></li><li class="listitem"><p>
566 Apogee Igniter Voltage. This indicates whether the apogee
567 igniter has continuity. If the igniter has a low
568 resistance, then the voltage measured here will be close
569 to the Li-Po battery voltage. A value greater than 3.2V is
570 required for a 'GO' status.
571 </p></li><li class="listitem"><p>
572 Main Igniter Voltage. This indicates whether the main
573 igniter has continuity. If the igniter has a low
574 resistance, then the voltage measured here will be close
575 to the Li-Po battery voltage. A value greater than 3.2V is
576 required for a 'GO' status.
577 </p></li><li class="listitem"><p>
578 On-board Data Logging. This indicates whether there is
579 space remaining on-board to store flight data for the
580 upcoming flight. If you've downloaded data, but failed
581 to erase flights, there may not be any space
582 left. TeleMetrum can store multiple flights, depending
583 on the configured maximum flight log size. TeleMini
584 stores only a single flight, so it will need to be
585 downloaded and erased after each flight to capture
586 data. This only affects on-board flight logging; the
587 altimeter will still transmit telemetry and fire
588 ejection charges at the proper times.
589 </p></li><li class="listitem"><p>
590 GPS Locked. For a TeleMetrum device, this indicates whether the GPS receiver is
591 currently able to compute position information. GPS requires
592 at least 4 satellites to compute an accurate position.
593 </p></li><li class="listitem"><p>
594 GPS Ready. For a TeleMetrum device, this indicates whether GPS has reported at least
595 10 consecutive positions without losing lock. This ensures
596 that the GPS receiver has reliable reception from the
598 </p></li></ul></div><p>
600 The Launchpad tab also shows the computed launch pad position
601 and altitude, averaging many reported positions to improve the
604 </p></div><div class="section" title="1.2. Ascent"><div class="titlepage"><div><div><h3 class="title"><a name="idp2194832"></a>1.2. Ascent</h3></div></div></div><p>
605 This tab is shown during Boost, Fast and Coast
606 phases. The information displayed here helps monitor the
607 rocket as it heads towards apogee.
609 The height, speed and acceleration are shown along with the
610 maximum values for each of them. This allows you to quickly
611 answer the most commonly asked questions you'll hear during
614 The current latitude and longitude reported by the TeleMetrum GPS are
615 also shown. Note that under high acceleration, these values
616 may not get updated as the GPS receiver loses position
617 fix. Once the rocket starts coasting, the receiver should
618 start reporting position again.
620 Finally, the current igniter voltages are reported as in the
621 Launch Pad tab. This can help diagnose deployment failures
622 caused by wiring which comes loose under high acceleration.
623 </p></div><div class="section" title="1.3. Descent"><div class="titlepage"><div><div><h3 class="title"><a name="idp3351928"></a>1.3. Descent</h3></div></div></div><p>
624 Once the rocket has reached apogee and (we hope) activated the
625 apogee charge, attention switches to tracking the rocket on
626 the way back to the ground, and for dual-deploy flights,
627 waiting for the main charge to fire.
629 To monitor whether the apogee charge operated correctly, the
630 current descent rate is reported along with the current
631 height. Good descent rates vary based on the choice of recovery
632 components, but generally range from 15-30m/s on drogue and should
633 be below 10m/s when under the main parachute in a dual-deploy flight.
635 For TeleMetrum altimeters, you can locate the rocket in the sky
636 using the elevation and
637 bearing information to figure out where to look. Elevation is
638 in degrees above the horizon. Bearing is reported in degrees
639 relative to true north. Range can help figure out how big the
640 rocket will appear. Note that all of these values are relative
641 to the pad location. If the elevation is near 90°, the rocket
642 is over the pad, not over you.
644 Finally, the igniter voltages are reported in this tab as
645 well, both to monitor the main charge as well as to see what
646 the status of the apogee charge is. Note that some commercial
647 e-matches are designed to retain continuity even after being
648 fired, and will continue to show as green or return from red to
650 </p></div><div class="section" title="1.4. Landed"><div class="titlepage"><div><div><h3 class="title"><a name="idp1234032"></a>1.4. Landed</h3></div></div></div><p>
651 Once the rocket is on the ground, attention switches to
652 recovery. While the radio signal is often lost once the
653 rocket is on the ground, the last reported GPS position is
654 generally within a short distance of the actual landing location.
656 The last reported GPS position is reported both by
657 latitude and longitude as well as a bearing and distance from
658 the launch pad. The distance should give you a good idea of
659 whether to walk or hitch a ride. Take the reported
660 latitude and longitude and enter them into your hand-held GPS
661 unit and have that compute a track to the landing location.
663 Both TeleMini and TeleMetrum will continue to transmit RDF
664 tones after landing, allowing you to locate the rocket by
665 following the radio signal if necessary. You may need to get
666 away from the clutter of the flight line, or even get up on
667 a hill (or your neighbor's RV roof) to receive the RDF signal.
669 The maximum height, speed and acceleration reported
670 during the flight are displayed for your admiring observers.
671 The accuracy of these immediate values depends on the quality
672 of your radio link and how many packets were received.
673 Recovering the on-board data after flight will likely yield
674 more precise results.
676 To get more detailed information about the flight, you can
677 click on the 'Graph Flight' button which will bring up a
678 graph window for the current flight.
679 </p></div><div class="section" title="1.5. Site Map"><div class="titlepage"><div><div><h3 class="title"><a name="idp3388472"></a>1.5. Site Map</h3></div></div></div><p>
680 When the TeleMetrum has a GPS fix, the Site Map tab will map
681 the rocket's position to make it easier for you to locate the
682 rocket, both while it is in the air, and when it has landed. The
683 rocket's state is indicated by color: white for pad, red for
684 boost, pink for fast, yellow for coast, light blue for drogue,
685 dark blue for main, and black for landed.
687 The map's scale is approximately 3m (10ft) per pixel. The map
688 can be dragged using the left mouse button. The map will attempt
689 to keep the rocket roughly centered while data is being received.
691 Images are fetched automatically via the Google Maps Static API,
692 and cached on disk for reuse. If map images cannot be downloaded,
693 the rocket's path will be traced on a dark gray background
696 You can pre-load images for your favorite launch sites
697 before you leave home; check out the 'Preload Maps' section below.
698 </p></div></div><div class="section" title="2. Save Flight Data"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp1930856"></a>2. Save Flight Data</h2></div></div></div><p>
699 The altimeter records flight data to its internal flash memory.
700 TeleMetrum data is recorded at a much higher rate than the telemetry
701 system can handle, and is not subject to radio drop-outs. As
702 such, it provides a more complete and precise record of the
703 flight. The 'Save Flight Data' button allows you to read the
704 flash memory and write it to disk. As TeleMini has only a barometer, it
705 records data at the same rate as the telemetry signal, but there will be
706 no data lost due to telemetry drop-outs.
708 Clicking on the 'Save Flight Data' button brings up a list of
709 connected TeleMetrum and TeleDongle devices. If you select a
710 TeleMetrum device, the flight data will be downloaded from that
711 device directly. If you select a TeleDongle device, flight data
712 will be downloaded from an altimeter over radio link via the
713 specified TeleDongle. See the chapter on Controlling An Altimeter
714 Over The Radio Link for more information.
716 After the device has been selected, a dialog showing the
717 flight data saved in the device will be shown allowing you to
718 select which flights to download and which to delete. With
719 version 0.9 or newer firmware, you must erase flights in order
720 for the space they consume to be reused by another
721 flight. This prevents accidentally losing flight data
722 if you neglect to download data before flying again. Note that
723 if there is no more space available in the device, then no
724 data will be recorded during the next flight.
726 The file name for each flight log is computed automatically
727 from the recorded flight date, altimeter serial number and
728 flight number information.
729 </p></div><div class="section" title="3. Replay Flight"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp3546840"></a>3. Replay Flight</h2></div></div></div><p>
730 Select this button and you are prompted to select a flight
731 record file, either a .telem file recording telemetry data or a
732 .eeprom file containing flight data saved from the altimeter
735 Once a flight record is selected, the flight monitor interface
736 is displayed and the flight is re-enacted in real time. Check
737 the Monitor Flight chapter above to learn how this window operates.
738 </p></div><div class="section" title="4. Graph Data"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp3331568"></a>4. Graph Data</h2></div></div></div><p>
739 Select this button and you are prompted to select a flight
740 record file, either a .telem file recording telemetry data or a
741 .eeprom file containing flight data saved from
744 Once a flight record is selected, a window with two tabs is
745 opened. The first tab contains a graph with acceleration
746 (blue), velocity (green) and altitude (red) of the flight,
747 measured in metric units. The
748 apogee(yellow) and main(magenta) igniter voltages are also
749 displayed; high voltages indicate continuity, low voltages
750 indicate open circuits. The second tab contains some basic
753 The graph can be zoomed into a particular area by clicking and
754 dragging down and to the right. Once zoomed, the graph can be
755 reset by clicking and dragging up and to the left. Holding down
756 control and clicking and dragging allows the graph to be panned.
757 The right mouse button causes a pop-up menu to be displayed, giving
758 you the option save or print the plot.
760 Note that telemetry files will generally produce poor graphs
761 due to the lower sampling rate and missed telemetry packets.
762 Use saved flight data in .eeprom files for graphing where possible.
763 </p></div><div class="section" title="5. Export Data"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp1385704"></a>5. Export Data</h2></div></div></div><p>
764 This tool takes the raw data files and makes them available for
765 external analysis. When you select this button, you are prompted to
767 data file (either .eeprom or .telem will do, remember that
768 .eeprom files contain higher resolution and more continuous
769 data). Next, a second dialog appears which is used to select
770 where to write the resulting file. It has a selector to choose
771 between CSV and KML file formats.
772 </p><div class="section" title="5.1. Comma Separated Value Format"><div class="titlepage"><div><div><h3 class="title"><a name="idp3437744"></a>5.1. Comma Separated Value Format</h3></div></div></div><p>
773 This is a text file containing the data in a form suitable for
774 import into a spreadsheet or other external data analysis
775 tool. The first few lines of the file contain the version and
776 configuration information from the altimeter, then
777 there is a single header line which labels all of the
778 fields. All of these lines start with a '#' character which
779 many tools can be configured to skip over.
781 The remaining lines of the file contain the data, with each
782 field separated by a comma and at least one space. All of
783 the sensor values are converted to standard units, with the
784 barometric data reported in both pressure, altitude and
785 height above pad units.
786 </p></div><div class="section" title="5.2. Keyhole Markup Language (for Google Earth)"><div class="titlepage"><div><div><h3 class="title"><a name="idp2912584"></a>5.2. Keyhole Markup Language (for Google Earth)</h3></div></div></div><p>
787 This is the format used by Google Earth to provide an overlay
788 within that application. With this, you can use Google Earth to
789 see the whole flight path in 3D.
790 </p></div></div><div class="section" title="6. Configure Altimeter"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp2438432"></a>6. Configure Altimeter</h2></div></div></div><p>
791 Select this button and then select either a TeleMetrum or
792 TeleDongle Device from the list provided. Selecting a TeleDongle
793 device will use the radio link to configure a remote altimeter.
795 The first few lines of the dialog provide information about the
796 connected device, including the product name,
797 software version and hardware serial number. Below that are the
798 individual configuration entries.
800 At the bottom of the dialog, there are four buttons:
801 </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>
802 Save. This writes any changes to the
803 configuration parameter block in flash memory. If you don't
804 press this button, any changes you make will be lost.
805 </p></li><li class="listitem"><p>
806 Reset. This resets the dialog to the most recently saved values,
807 erasing any changes you have made.
808 </p></li><li class="listitem"><p>
809 Reboot. This reboots the device. Use this to
810 switch from idle to pad mode by rebooting once the rocket is
811 oriented for flight, or to confirm changes you think you saved
813 </p></li><li class="listitem"><p>
814 Close. This closes the dialog. Any unsaved changes will be
816 </p></li></ul></div><p>
817 The rest of the dialog contains the parameters to be configured.
818 </p><div class="section" title="6.1. Main Deploy Altitude"><div class="titlepage"><div><div><h3 class="title"><a name="idp3551544"></a>6.1. Main Deploy Altitude</h3></div></div></div><p>
819 This sets the altitude (above the recorded pad altitude) at
820 which the 'main' igniter will fire. The drop-down menu shows
821 some common values, but you can edit the text directly and
822 choose whatever you like. If the apogee charge fires below
823 this altitude, then the main charge will fire two seconds
824 after the apogee charge fires.
825 </p></div><div class="section" title="6.2. Apogee Delay"><div class="titlepage"><div><div><h3 class="title"><a name="idp2848008"></a>6.2. Apogee Delay</h3></div></div></div><p>
826 When flying redundant electronics, it's often important to
827 ensure that multiple apogee charges don't fire at precisely
828 the same time, as that can over pressurize the apogee deployment
829 bay and cause a structural failure of the air-frame. The Apogee
830 Delay parameter tells the flight computer to fire the apogee
831 charge a certain number of seconds after apogee has been
833 </p></div><div class="section" title="6.3. Radio Frequency"><div class="titlepage"><div><div><h3 class="title"><a name="idp3459616"></a>6.3. Radio Frequency</h3></div></div></div><p>
834 This configures which of the configured frequencies to use for both
835 telemetry and packet command mode. Note that if you set this
836 value via packet command mode, you will have to reconfigure
837 the TeleDongle frequency before you will be able to use packet
839 </p></div><div class="section" title="6.4. Radio Calibration"><div class="titlepage"><div><div><h3 class="title"><a name="idp2329488"></a>6.4. Radio Calibration</h3></div></div></div><p>
840 The radios in every Altus Metrum device are calibrated at the
841 factory to ensure that they transmit and receive on the
842 specified frequency. If you need to you can adjust the calibration
843 by changing this value. Do not do this without understanding what
844 the value means, read the appendix on calibration and/or the source
845 code for more information. To change a TeleDongle's calibration,
846 you must reprogram the unit completely.
847 </p></div><div class="section" title="6.5. Callsign"><div class="titlepage"><div><div><h3 class="title"><a name="idp3507216"></a>6.5. Callsign</h3></div></div></div><p>
848 This sets the call sign included in each telemetry packet. Set this
849 as needed to conform to your local radio regulations.
850 </p></div><div class="section" title="6.6. Maximum Flight Log Size"><div class="titlepage"><div><div><h3 class="title"><a name="idp1223488"></a>6.6. Maximum Flight Log Size</h3></div></div></div><p>
851 This sets the space (in kilobytes) allocated for each flight
852 log. The available space will be divided into chunks of this
853 size. A smaller value will allow more flights to be stored,
854 a larger value will record data from longer flights.
855 </p></div><div class="section" title="6.7. Ignite Mode"><div class="titlepage"><div><div><h3 class="title"><a name="idp3489504"></a>6.7. Ignite Mode</h3></div></div></div><p>
856 TeleMetrum and TeleMini provide two igniter channels as they
857 were originally designed as dual-deploy flight
858 computers. This configuration parameter allows the two
859 channels to be used in different configurations.
860 </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>
861 Dual Deploy. This is the usual mode of operation; the
862 'apogee' channel is fired at apogee and the 'main'
863 channel at the height above ground specified by the
864 'Main Deploy Altitude' during descent.
865 </p></li><li class="listitem"><p>
866 Redundant Apogee. This fires both channels at
867 apogee, the 'apogee' channel first followed after a two second
868 delay by the 'main' channel.
869 </p></li><li class="listitem"><p>
870 Redundant Main. This fires both channels at the
871 height above ground specified by the Main Deploy
872 Altitude setting during descent. The 'apogee'
873 channel is fired first, followed after a two second
874 delay by the 'main' channel.
875 </p></li></ul></div></div><div class="section" title="6.8. Pad Orientation"><div class="titlepage"><div><div><h3 class="title"><a name="idp1526824"></a>6.8. Pad Orientation</h3></div></div></div><p>
876 Because it includes an accelerometer, TeleMetrum is
877 sensitive to the orientation of the board. By default, it
878 expects the antenna end to point forward. This parameter
879 allows that default to be changed, permitting the board to
880 be mounted with the antenna pointing aft instead.
881 </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>
882 Antenna Up. In this mode, the antenna end of the
883 TeleMetrum board must point forward, in line with the
884 expected flight path.
885 </p></li><li class="listitem"><p>
886 Antenna Down. In this mode, the antenna end of the
887 TeleMetrum board must point aft, in line with the
888 expected flight path.
889 </p></li></ul></div></div></div><div class="section" title="7. Configure AltosUI"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp2433504"></a>7. Configure AltosUI</h2></div></div></div><p>
890 This button presents a dialog so that you can configure the AltosUI global settings.
891 </p><div class="section" title="7.1. Voice Settings"><div class="titlepage"><div><div><h3 class="title"><a name="idp3510984"></a>7.1. Voice Settings</h3></div></div></div><p>
892 AltosUI provides voice announcements during flight so that you
893 can keep your eyes on the sky and still get information about
894 the current flight status. However, sometimes you don't want
896 </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>Enable—turns all voice announcements on and off</p></li><li class="listitem"><p>
897 Test Voice—Plays a short message allowing you to verify
898 that the audio system is working and the volume settings
900 </p></li></ul></div></div><div class="section" title="7.2. Log Directory"><div class="titlepage"><div><div><h3 class="title"><a name="idp2029264"></a>7.2. Log Directory</h3></div></div></div><p>
901 AltosUI logs all telemetry data and saves all TeleMetrum flash
902 data to this directory. This directory is also used as the
903 staring point when selecting data files for display or export.
905 Click on the directory name to bring up a directory choosing
906 dialog, select a new directory and click 'Select Directory' to
907 change where AltosUI reads and writes data files.
908 </p></div><div class="section" title="7.3. Callsign"><div class="titlepage"><div><div><h3 class="title"><a name="idp2350072"></a>7.3. Callsign</h3></div></div></div><p>
909 This value is transmitted in each command packet sent from
910 TeleDongle and received from an altimeter. It is not used in
911 telemetry mode, as the callsign configured in the altimeter board
912 is included in all telemetry packets. Configure this
913 with the AltosUI operators call sign as needed to comply with
914 your local radio regulations.
915 </p></div><div class="section" title="7.4. Font Size"><div class="titlepage"><div><div><h3 class="title"><a name="idp2694528"></a>7.4. Font Size</h3></div></div></div><p>
916 Selects the set of fonts used in the flight monitor
917 window. Choose between the small, medium and large sets.
918 </p></div><div class="section" title="7.5. Serial Debug"><div class="titlepage"><div><div><h3 class="title"><a name="idp1856992"></a>7.5. Serial Debug</h3></div></div></div><p>
919 This causes all communication with a connected device to be
920 dumped to the console from which AltosUI was started. If
921 you've started it from an icon or menu entry, the output
922 will simply be discarded. This mode can be useful to debug
923 various serial communication issues.
924 </p></div><div class="section" title="7.6. Manage Frequencies"><div class="titlepage"><div><div><h3 class="title"><a name="idp1891664"></a>7.6. Manage Frequencies</h3></div></div></div><p>
925 This brings up a dialog where you can configure the set of
926 frequencies shown in the various frequency menus. You can
927 add as many as you like, or even reconfigure the default
928 set. Changing this list does not affect the frequency
929 settings of any devices, it only changes the set of
930 frequencies shown in the menus.
931 </p></div></div><div class="section" title="8. Flash Image"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp3058032"></a>8. Flash Image</h2></div></div></div><p>
932 This reprograms any Altus Metrum device by using a TeleMetrum
933 or TeleDongle as a programming dongle. Please read the
934 directions for flashing devices in the Updating Device
935 Firmware chapter below.
937 Once you have the programmer and target devices connected,
938 push the 'Flash Image' button. That will present a dialog box
939 listing all of the connected devices. Carefully select the
940 programmer device, not the device to be programmed.
942 Next, select the image to flash to the device. These are named
943 with the product name and firmware version. The file selector
944 will start in the directory containing the firmware included
945 with the AltosUI package. Navigate to the directory containing
946 the desired firmware if it isn't there.
948 Next, a small dialog containing the device serial number and
949 RF calibration values should appear. If these values are
950 incorrect (possibly due to a corrupted image in the device),
951 enter the correct values here.
953 Finally, a dialog containing a progress bar will follow the
956 When programming is complete, the target device will
957 reboot. Note that if the target device is connected via USB, you
958 will have to unplug it and then plug it back in for the USB
959 connection to reset so that you can communicate with the device
961 </p></div><div class="section" title="9. Fire Igniter"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp3184648"></a>9. Fire Igniter</h2></div></div></div><p>
962 This activates the igniter circuits in TeleMetrum to help test
963 recovery systems deployment. Because this command can operate
964 over the Packet Command Link, you can prepare the rocket as
965 for flight and then test the recovery system without needing
966 to snake wires inside the air-frame.
968 Selecting the 'Fire Igniter' button brings up the usual device
969 selection dialog. Pick the desired TeleDongle or TeleMetrum
970 device. This brings up another window which shows the current
971 continuity test status for both apogee and main charges.
973 Next, select the desired igniter to fire. This will enable the
976 Select the 'Arm' button. This enables the 'Fire' button. The
977 word 'Arm' is replaced by a countdown timer indicating that
978 you have 10 seconds to press the 'Fire' button or the system
979 will deactivate, at which point you start over again at
980 selecting the desired igniter.
981 </p></div><div class="section" title="10. Scan Channels"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp1519784"></a>10. Scan Channels</h2></div></div></div><p>
982 This listens for telemetry packets on all of the configured
983 frequencies, displaying information about each device it
984 receives a packet from. You can select which of the three
985 telemetry formats should be tried; by default, it only listens
986 for the standard telemetry packets used in v1.0 and later
988 </p></div><div class="section" title="11. Load Maps"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp2057448"></a>11. Load Maps</h2></div></div></div><p>
989 Before heading out to a new launch site, you can use this to
990 load satellite images in case you don't have internet
991 connectivity at the site. This loads a fairly large area
992 around the launch site, which should cover any flight you're likely to make.
994 There's a drop-down menu of launch sites we know about; if
995 your favorites aren't there, please let us know the lat/lon
996 and name of the site. The contents of this list are actually
997 downloaded at run-time, so as new sites are sent in, they'll
998 get automatically added to this list.
1000 If the launch site isn't in the list, you can manually enter the lat/lon values
1002 Clicking the 'Load Map' button will fetch images from Google
1003 Maps; note that Google limits how many images you can fetch at
1004 once, so if you load more than one launch site, you may get
1005 some gray areas in the map which indicate that Google is tired
1006 of sending data to you. Try again later.
1007 </p></div><div class="section" title="12. Monitor Idle"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp1472424"></a>12. Monitor Idle</h2></div></div></div><p>
1008 This brings up a dialog similar to the Monitor Flight UI,
1009 except it works with the altimeter in "idle" mode by sending
1010 query commands to discover the current state rather than
1011 listening for telemetry packets.
1012 </p></div></div><div class="chapter" title="Chapter 7. Using Altus Metrum Products"><div class="titlepage"><div><div><h2 class="title"><a name="idp3231728"></a>Chapter 7. 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="#idp2024456">1. Being Legal</a></span></dt><dt><span class="section"><a href="#idp2425408">2. In the Rocket</a></span></dt><dt><span class="section"><a href="#idp2236704">3. On the Ground</a></span></dt><dt><span class="section"><a href="#idp2243664">4. Data Analysis</a></span></dt><dt><span class="section"><a href="#idp2104880">5. Future Plans</a></span></dt></dl></div><div class="section" title="1. Being Legal"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp2024456"></a>1. Being Legal</h2></div></div></div><p>
1013 First off, in the US, you need an <a class="ulink" href="http://www.altusmetrum.org/Radio/" target="_top">amateur radio license</a> or
1014 other authorization to legally operate the radio transmitters that are part
1016 </p></div><div class="section" title="2. In the Rocket"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp2425408"></a>2. In the Rocket</h2></div></div></div><p>
1017 In the rocket itself, you just need a <a class="ulink" href="http://www.altusmetrum.org/TeleMetrum/" target="_top">TeleMetrum</a> or
1018 <a class="ulink" href="http://www.altusmetrum.org/TeleMini/" target="_top">TeleMini</a> board and
1019 a Li-Po rechargeable battery. An 860mAh battery weighs less than a 9V
1020 alkaline battery, and will run a TeleMetrum for hours.
1021 A 110mAh battery weighs less than a triple A battery and will run a TeleMetrum for
1022 a few hours, or a TeleMini for much (much) longer.
1024 By default, we ship the altimeters with a simple wire antenna. If your
1025 electronics bay or the air-frame it resides within is made of carbon fiber,
1026 which is opaque to RF signals, you may choose to have an SMA connector
1027 installed so that you can run a coaxial cable to an antenna mounted
1028 elsewhere in the rocket.
1029 </p></div><div class="section" title="3. On the Ground"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp2236704"></a>3. On the Ground</h2></div></div></div><p>
1030 To receive the data stream from the rocket, you need an antenna and short
1031 feed-line connected to one of our <a class="ulink" href="http://www.altusmetrum.org/TeleDongle/" target="_top">TeleDongle</a> units. The
1032 TeleDongle in turn plugs directly into the USB port on a notebook
1033 computer. Because TeleDongle looks like a simple serial port, your computer
1034 does not require special device drivers... just plug it in.
1036 The GUI tool, AltosUI, is written in Java and runs across
1037 Linux, Mac OS and Windows. There's also a suite of C tools
1038 for Linux which can perform most of the same tasks.
1040 After the flight, you can use the radio link to extract the more detailed data
1041 logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
1042 TeleMetrum board directly. Pulling out the data without having to open up
1043 the rocket is pretty cool! A USB cable is also how you charge the Li-Po
1044 battery, so you'll want one of those anyway... the same cable used by lots
1045 of digital cameras and other modern electronic stuff will work fine.
1047 If your TeleMetrum-equipped rocket lands out of sight, you may enjoy having a hand-held GPS
1048 receiver, so that you can put in a way-point for the last reported rocket
1049 position before touch-down. This makes looking for your rocket a lot like
1050 Geo-Caching... just go to the way-point and look around starting from there.
1052 You may also enjoy having a ham radio "HT" that covers the 70cm band... you
1053 can use that with your antenna to direction-find the rocket on the ground
1054 the same way you can use a Walston or Beeline tracker. This can be handy
1055 if the rocket is hiding in sage brush or a tree, or if the last GPS position
1056 doesn't get you close enough because the rocket dropped into a canyon, or
1057 the wind is blowing it across a dry lake bed, or something like that... Keith
1058 and Bdale both currently own and use the Yaesu VX-7R at launches.
1060 So, to recap, on the ground the hardware you'll need includes:
1061 </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
1062 an antenna and feed-line
1063 </li><li class="listitem">
1065 </li><li class="listitem">
1067 </li><li class="listitem">
1068 optionally, a hand-held GPS receiver
1069 </li><li class="listitem">
1070 optionally, an HT or receiver covering 435 MHz
1073 The best hand-held commercial directional antennas we've found for radio
1074 direction finding rockets are from
1075 <a class="ulink" href="http://www.arrowantennas.com/" target="_top">
1078 The 440-3 and 440-5 are both good choices for finding a
1079 TeleMetrum- or TeleMini- equipped rocket when used with a suitable 70cm HT.
1080 </p></div><div class="section" title="4. Data Analysis"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp2243664"></a>4. Data Analysis</h2></div></div></div><p>
1081 Our software makes it easy to log the data from each flight, both the
1082 telemetry received during the flight itself, and the more
1083 complete data log recorded in the flash memory on the altimeter
1084 board. Once this data is on your computer, our post-flight tools make it
1085 easy to quickly get to the numbers everyone wants, like apogee altitude,
1086 max acceleration, and max velocity. You can also generate and view a
1087 standard set of plots showing the altitude, acceleration, and
1088 velocity of the rocket during flight. And you can even export a TeleMetrum data file
1089 usable with Google Maps and Google Earth for visualizing the flight path
1090 in two or three dimensions!
1092 Our ultimate goal is to emit a set of files for each flight that can be
1093 published as a web page per flight, or just viewed on your local disk with
1095 </p></div><div class="section" title="5. Future Plans"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp2104880"></a>5. Future Plans</h2></div></div></div><p>
1096 In the future, we intend to offer "companion boards" for the rocket that will
1097 plug in to TeleMetrum to collect additional data, provide more pyro channels,
1100 We are also working on the design of a hand-held ground terminal that will
1101 allow monitoring the rocket's status, collecting data during flight, and
1102 logging data after flight without the need for a notebook computer on the
1103 flight line. Particularly since it is so difficult to read most notebook
1104 screens in direct sunlight, we think this will be a great thing to have.
1106 Because all of our work is open, both the hardware designs and the software,
1107 if you have some great idea for an addition to the current Altus Metrum family,
1108 feel free to dive in and help! Or let us know what you'd like to see that
1109 we aren't already working on, and maybe we'll get excited about it too...
1110 </p></div></div><div class="chapter" title="Chapter 8. Altimeter Installation Recommendations"><div class="titlepage"><div><div><h2 class="title"><a name="idp3340600"></a>Chapter 8. Altimeter Installation Recommendations</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#idp3522016">1. Mounting the Altimeter</a></span></dt><dt><span class="section"><a href="#idp2062944">2. Dealing with the Antenna</a></span></dt><dt><span class="section"><a href="#idp2075472">3. Preserving GPS Reception</a></span></dt><dt><span class="section"><a href="#idp1887864">4. Radio Frequency Interference</a></span></dt><dt><span class="section"><a href="#idp2902592">5. The Barometric Sensor</a></span></dt><dt><span class="section"><a href="#idp2991488">6. Ground Testing</a></span></dt></dl></div><p>
1111 Building high-power rockets that fly safely is hard enough. Mix
1112 in some sophisticated electronics and a bunch of radio energy
1113 and oftentimes you find few perfect solutions. This chapter
1114 contains some suggestions about how to install Altus Metrum
1115 products into the rocket air-frame, including how to safely and
1116 reliably mix a variety of electronics into the same air-frame.
1117 </p><div class="section" title="1. Mounting the Altimeter"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp3522016"></a>1. Mounting the Altimeter</h2></div></div></div><p>
1118 The first consideration is to ensure that the altimeter is
1119 securely fastened to the air-frame. For TeleMetrum, we use
1120 nylon standoffs and nylon screws; they're good to at least 50G
1121 and cannot cause any electrical issues on the board. For
1122 TeleMini, we usually cut small pieces of 1/16" balsa to fit
1123 under the screw holes, and then take 2x56 nylon screws and
1124 screw them through the TeleMini mounting holes, through the
1125 balsa and into the underlying material.
1126 </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
1127 Make sure TeleMetrum is aligned precisely along the axis of
1128 acceleration so that the accelerometer can accurately
1129 capture data during the flight.
1130 </li><li class="listitem">
1131 Watch for any metal touching components on the
1132 board. Shorting out connections on the bottom of the board
1133 can cause the altimeter to fail during flight.
1134 </li></ol></div></div><div class="section" title="2. Dealing with the Antenna"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp2062944"></a>2. Dealing with the Antenna</h2></div></div></div><p>
1135 The antenna supplied is just a piece of solid, insulated,
1136 wire. If it gets damaged or broken, it can be easily
1137 replaced. It should be kept straight and not cut; bending or
1138 cutting it will change the resonant frequency and/or
1139 impedance, making it a less efficient radiator and thus
1140 reducing the range of the telemetry signal.
1142 Keeping metal away from the antenna will provide better range
1143 and a more even radiation pattern. In most rockets, it's not
1144 entirely possible to isolate the antenna from metal
1145 components; there are often bolts, all-thread and wires from other
1146 electronics to contend with. Just be aware that the more stuff
1147 like this around the antenna, the lower the range.
1149 Make sure the antenna is not inside a tube made or covered
1150 with conducting material. Carbon fiber is the most common
1151 culprit here -- CF is a good conductor and will effectively
1152 shield the antenna, dramatically reducing signal strength and
1153 range. Metallic flake paint is another effective shielding
1154 material which is to be avoided around any antennas.
1156 If the ebay is large enough, it can be convenient to simply
1157 mount the altimeter at one end and stretch the antenna out
1158 inside. Taping the antenna to the sled can keep it straight
1159 under acceleration. If there are metal rods, keep the
1160 antenna as far away as possible.
1162 For a shorter ebay, it's quite practical to have the antenna
1163 run through a bulkhead and into an adjacent bay. Drill a small
1164 hole in the bulkhead, pass the antenna wire through it and
1165 then seal it up with glue or clay. We've also used acrylic
1166 tubing to create a cavity for the antenna wire. This works a
1167 bit better in that the antenna is known to stay straight and
1168 not get folded by recovery components in the bay. Angle the
1169 tubing towards the side wall of the rocket and it ends up
1170 consuming very little space.
1172 If you need to place the antenna at a distance from the
1173 altimeter, you can replace the antenna with an edge-mounted
1174 SMA connector, and then run 50Ω coax from the board to the
1175 antenna. Building a remote antenna is beyond the scope of this
1177 </p></div><div class="section" title="3. Preserving GPS Reception"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp2075472"></a>3. Preserving GPS Reception</h2></div></div></div><p>
1178 The GPS antenna and receiver in TeleMetrum are highly
1179 sensitive and normally have no trouble tracking enough
1180 satellites to provide accurate position information for
1181 recovering the rocket. However, there are many ways to
1182 attenuate the GPS signal.
1183 </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
1184 Conductive tubing or coatings. Carbon fiber and metal
1185 tubing, or metallic paint will all dramatically attenuate the
1186 GPS signal. We've never heard of anyone successfully
1187 receiving GPS from inside these materials.
1188 </li><li class="listitem">
1189 Metal components near the GPS patch antenna. These will
1190 de-tune the patch antenna, changing the resonant frequency
1191 away from the L1 carrier and reduce the effectiveness of the
1192 antenna. You can place as much stuff as you like beneath the
1193 antenna as that's covered with a ground plane. But, keep
1194 wires and metal out from above the patch antenna.
1196 </p></div><div class="section" title="4. Radio Frequency Interference"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp1887864"></a>4. Radio Frequency Interference</h2></div></div></div><p>
1197 Any altimeter will generate RFI; the digital circuits use
1198 high-frequency clocks that spray radio interference across a
1199 wide band. Altus Metrum altimeters generate intentional radio
1200 signals as well, increasing the amount of RF energy around the board.
1202 Rocketry altimeters also use precise sensors measuring air
1203 pressure and acceleration. Tiny changes in voltage can cause
1204 these sensor readings to vary by a huge amount. When the
1205 sensors start mis-reporting data, the altimeter can either
1206 fire the igniters at the wrong time, or not fire them at all.
1208 Voltages are induced when radio frequency energy is
1209 transmitted from one circuit to another. Here are things that
1210 influence the induced voltage and current:
1211 </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
1212 Keep wires from different circuits apart. Moving circuits
1213 further apart will reduce RFI.
1214 </li><li class="listitem">
1215 Avoid parallel wires from different circuits. The longer two
1216 wires run parallel to one another, the larger the amount of
1217 transferred energy. Cross wires at right angles to reduce
1219 </li><li class="listitem">
1220 Twist wires from the same circuits. Two wires the same
1221 distance from the transmitter will get the same amount of
1222 induced energy which will then cancel out. Any time you have
1223 a wire pair running together, twist the pair together to
1224 even out distances and reduce RFI. For altimeters, this
1225 includes battery leads, switch hookups and igniter
1227 </li><li class="listitem">
1228 Avoid resonant lengths. Know what frequencies are present
1229 in the environment and avoid having wire lengths near a
1230 natural resonant length. Altusmetrum products transmit on the
1231 70cm amateur band, so you should avoid lengths that are a
1232 simple ratio of that length; essentially any multiple of 1/4
1233 of the wavelength (17.5cm).
1234 </li></ul></div></div><div class="section" title="5. The Barometric Sensor"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp2902592"></a>5. The Barometric Sensor</h2></div></div></div><p>
1235 Altusmetrum altimeters measure altitude with a barometric
1236 sensor, essentially measuring the amount of air above the
1237 rocket to figure out how high it is. A large number of
1238 measurements are taken as the altimeter initializes itself to
1239 figure out the pad altitude. Subsequent measurements are then
1240 used to compute the height above the pad.
1242 To accurately measure atmospheric pressure, the ebay
1243 containing the altimeter must be vented outside the
1244 air-frame. The vent must be placed in a region of linear
1245 airflow, have smooth edges, and away from areas of increasing or
1246 decreasing pressure.
1248 The barometric sensor in the altimeter is quite sensitive to
1249 chemical damage from the products of APCP or BP combustion, so
1250 make sure the ebay is carefully sealed from any compartment
1251 which contains ejection charges or motors.
1252 </p></div><div class="section" title="6. Ground Testing"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp2991488"></a>6. Ground Testing</h2></div></div></div><p>
1253 The most important aspect of any installation is careful
1254 ground testing. Bringing an air-frame up to the LCO table which
1255 hasn't been ground tested can lead to delays or ejection
1256 charges firing on the pad, or, even worse, a recovery system
1259 Do a 'full systems' test that includes wiring up all igniters
1260 without any BP and turning on all of the electronics in flight
1261 mode. This will catch any mistakes in wiring and any residual
1262 RFI issues that might accidentally fire igniters at the wrong
1263 time. Let the air-frame sit for several minutes, checking for
1264 adequate telemetry signal strength and GPS lock. If any igniters
1265 fire unexpectedly, find and resolve the issue before loading any
1268 Ground test the ejection charges. Prepare the rocket for
1269 flight, loading ejection charges and igniters. Completely
1270 assemble the air-frame and then use the 'Fire Igniters'
1271 interface through a TeleDongle to command each charge to
1272 fire. Make sure the charge is sufficient to robustly separate
1273 the air-frame and deploy the recovery system.
1274 </p></div></div><div class="chapter" title="Chapter 9. Updating Device Firmware"><div class="titlepage"><div><div><h2 class="title"><a name="idp2336184"></a>Chapter 9. Updating Device Firmware</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#idp3061016">1. Updating TeleMetrum Firmware</a></span></dt><dt><span class="section"><a href="#idp1980776">2. Updating TeleMini Firmware</a></span></dt><dt><span class="section"><a href="#idp2731488">3. Updating TeleDongle Firmware</a></span></dt></dl></div><p>
1275 The big concept to understand is that you have to use a
1276 TeleDongle as a programmer to update a TeleMetrum or TeleMini,
1277 and a TeleMetrum or other TeleDongle to program the TeleDongle
1278 Due to limited memory resources in the cc1111, we don't support
1279 programming directly over USB.
1281 You may wish to begin by ensuring you have current firmware images.
1282 These are distributed as part of the AltOS software bundle that
1283 also includes the AltosUI ground station program. Newer ground
1284 station versions typically work fine with older firmware versions,
1285 so you don't need to update your devices just to try out new
1286 software features. You can always download the most recent
1287 version from <a class="ulink" href="http://www.altusmetrum.org/AltOS/" target="_top">http://www.altusmetrum.org/AltOS/</a>.
1289 We recommend updating the altimeter first, before updating TeleDongle.
1290 </p><div class="section" title="1. Updating TeleMetrum Firmware"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp3061016"></a>1. Updating TeleMetrum Firmware</h2></div></div></div><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
1291 Find the 'programming cable' that you got as part of the starter
1292 kit, that has a red 8-pin MicroMaTch connector on one end and a
1293 red 4-pin MicroMaTch connector on the other end.
1294 </li><li class="listitem">
1295 Take the 2 screws out of the TeleDongle case to get access
1296 to the circuit board.
1297 </li><li class="listitem">
1298 Plug the 8-pin end of the programming cable to the
1299 matching connector on the TeleDongle, and the 4-pin end to the
1300 matching connector on the TeleMetrum.
1301 Note that each MicroMaTch connector has an alignment pin that
1302 goes through a hole in the PC board when you have the cable
1304 </li><li class="listitem">
1305 Attach a battery to the TeleMetrum board.
1306 </li><li class="listitem">
1307 Plug the TeleDongle into your computer's USB port, and power
1309 </li><li class="listitem">
1310 Run AltosUI, and select 'Flash Image' from the File menu.
1311 </li><li class="listitem">
1312 Pick the TeleDongle device from the list, identifying it as the
1314 </li><li class="listitem">
1315 Select the image you want put on the TeleMetrum, which should have a
1316 name in the form telemetrum-v1.1-1.0.0.ihx. It should be visible
1317 in the default directory, if not you may have to poke around
1318 your system to find it.
1319 </li><li class="listitem">
1320 Make sure the configuration parameters are reasonable
1321 looking. If the serial number and/or RF configuration
1322 values aren't right, you'll need to change them.
1323 </li><li class="listitem">
1324 Hit the 'OK' button and the software should proceed to flash
1325 the TeleMetrum with new firmware, showing a progress bar.
1326 </li><li class="listitem">
1327 Confirm that the TeleMetrum board seems to have updated OK, which you
1328 can do by plugging in to it over USB and using a terminal program
1329 to connect to the board and issue the 'v' command to check
1331 </li><li class="listitem">
1332 If something goes wrong, give it another try.
1333 </li></ol></div></div><div class="section" title="2. Updating TeleMini Firmware"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp1980776"></a>2. Updating TeleMini Firmware</h2></div></div></div><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
1334 You'll need a special 'programming cable' to reprogram the
1335 TeleMini. It's available on the Altus Metrum web store, or
1336 you can make your own using an 8-pin MicroMaTch connector on
1337 one end and a set of four pins on the other.
1338 </li><li class="listitem">
1339 Take the 2 screws out of the TeleDongle case to get access
1340 to the circuit board.
1341 </li><li class="listitem">
1342 Plug the 8-pin end of the programming cable to the matching
1343 connector on the TeleDongle, and the 4-pins into the holes
1344 in the TeleMini circuit board. Note that the MicroMaTch
1345 connector has an alignment pin that goes through a hole in
1346 the PC board when you have the cable oriented correctly, and
1347 that pin 1 on the TeleMini board is marked with a square pad
1348 while the other pins have round pads.
1349 </li><li class="listitem">
1350 Attach a battery to the TeleMini board.
1351 </li><li class="listitem">
1352 Plug the TeleDongle into your computer's USB port, and power
1354 </li><li class="listitem">
1355 Run AltosUI, and select 'Flash Image' from the File menu.
1356 </li><li class="listitem">
1357 Pick the TeleDongle device from the list, identifying it as the
1359 </li><li class="listitem">
1360 Select the image you want put on the TeleMini, which should have a
1361 name in the form telemini-v1.0-1.0.0.ihx. It should be visible
1362 in the default directory, if not you may have to poke around
1363 your system to find it.
1364 </li><li class="listitem">
1365 Make sure the configuration parameters are reasonable
1366 looking. If the serial number and/or RF configuration
1367 values aren't right, you'll need to change them.
1368 </li><li class="listitem">
1369 Hit the 'OK' button and the software should proceed to flash
1370 the TeleMini with new firmware, showing a progress bar.
1371 </li><li class="listitem">
1372 Confirm that the TeleMini board seems to have updated OK, which you
1373 can do by configuring it over the radio link through the TeleDongle, or
1374 letting it come up in "flight" mode and listening for telemetry.
1375 </li><li class="listitem">
1376 If something goes wrong, give it another try.
1377 </li></ol></div></div><div class="section" title="3. Updating TeleDongle Firmware"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp2731488"></a>3. Updating TeleDongle Firmware</h2></div></div></div><p>
1378 Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
1379 firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
1380 </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
1381 Find the 'programming cable' that you got as part of the starter
1382 kit, that has a red 8-pin MicroMaTch connector on one end and a
1383 red 4-pin MicroMaTch connector on the other end.
1384 </li><li class="listitem">
1385 Find the USB cable that you got as part of the starter kit, and
1386 plug the "mini" end in to the mating connector on TeleMetrum or TeleDongle.
1387 </li><li class="listitem">
1388 Take the 2 screws out of the TeleDongle case to get access
1389 to the circuit board.
1390 </li><li class="listitem">
1391 Plug the 8-pin end of the programming cable to the
1392 matching connector on the programmer, and the 4-pin end to the
1393 matching connector on the TeleDongle.
1394 Note that each MicroMaTch connector has an alignment pin that
1395 goes through a hole in the PC board when you have the cable
1397 </li><li class="listitem">
1398 Attach a battery to the TeleMetrum board if you're using one.
1399 </li><li class="listitem">
1400 Plug both the programmer and the TeleDongle into your computer's USB
1401 ports, and power up the programmer.
1402 </li><li class="listitem">
1403 Run AltosUI, and select 'Flash Image' from the File menu.
1404 </li><li class="listitem">
1405 Pick the programmer device from the list, identifying it as the
1407 </li><li class="listitem">
1408 Select the image you want put on the TeleDongle, which should have a
1409 name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
1410 in the default directory, if not you may have to poke around
1411 your system to find it.
1412 </li><li class="listitem">
1413 Make sure the configuration parameters are reasonable
1414 looking. If the serial number and/or RF configuration
1415 values aren't right, you'll need to change them. The TeleDongle
1416 serial number is on the "bottom" of the circuit board, and can
1417 usually be read through the translucent blue plastic case without
1418 needing to remove the board from the case.
1419 </li><li class="listitem">
1420 Hit the 'OK' button and the software should proceed to flash
1421 the TeleDongle with new firmware, showing a progress bar.
1422 </li><li class="listitem">
1423 Confirm that the TeleDongle board seems to have updated OK, which you
1424 can do by plugging in to it over USB and using a terminal program
1425 to connect to the board and issue the 'v' command to check
1426 the version, etc. Once you're happy, remove the programming cable
1427 and put the cover back on the TeleDongle.
1428 </li><li class="listitem">
1429 If something goes wrong, give it another try.
1431 Be careful removing the programming cable from the locking 8-pin
1432 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
1433 screwdriver or knife blade to gently pry the locking ears out
1434 slightly to extract the connector. We used a locking connector on
1435 TeleMetrum to help ensure that the cabling to companion boards
1436 used in a rocket don't ever come loose accidentally in flight.
1437 </p></div></div><div class="chapter" title="Chapter 10. Hardware Specifications"><div class="titlepage"><div><div><h2 class="title"><a name="idp2742616"></a>Chapter 10. Hardware Specifications</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#idp3450088">1. TeleMetrum Specifications</a></span></dt><dt><span class="section"><a href="#idp2397848">2. TeleMini Specifications</a></span></dt></dl></div><div class="section" title="1. TeleMetrum Specifications"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp3450088"></a>1. TeleMetrum Specifications</h2></div></div></div><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>
1438 Recording altimeter for model rocketry.
1439 </p></li><li class="listitem"><p>
1440 Supports dual deployment (can fire 2 ejection charges).
1441 </p></li><li class="listitem"><p>
1442 70cm ham-band transceiver for telemetry down-link.
1443 </p></li><li class="listitem"><p>
1444 Barometric pressure sensor good to 45k feet MSL.
1445 </p></li><li class="listitem"><p>
1446 1-axis high-g accelerometer for motor characterization, capable of
1447 +/- 50g using default part.
1448 </p></li><li class="listitem"><p>
1449 On-board, integrated GPS receiver with 5Hz update rate capability.
1450 </p></li><li class="listitem"><p>
1451 On-board 1 megabyte non-volatile memory for flight data storage.
1452 </p></li><li class="listitem"><p>
1453 USB interface for battery charging, configuration, and data recovery.
1454 </p></li><li class="listitem"><p>
1455 Fully integrated support for Li-Po rechargeable batteries.
1456 </p></li><li class="listitem"><p>
1457 Uses Li-Po to fire e-matches, can be modified to support
1458 optional separate pyro battery if needed.
1459 </p></li><li class="listitem"><p>
1460 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
1461 </p></li></ul></div></div><div class="section" title="2. TeleMini Specifications"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp2397848"></a>2. TeleMini Specifications</h2></div></div></div><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>
1462 Recording altimeter for model rocketry.
1463 </p></li><li class="listitem"><p>
1464 Supports dual deployment (can fire 2 ejection charges).
1465 </p></li><li class="listitem"><p>
1466 70cm ham-band transceiver for telemetry down-link.
1467 </p></li><li class="listitem"><p>
1468 Barometric pressure sensor good to 45k feet MSL.
1469 </p></li><li class="listitem"><p>
1470 On-board 5 kilobyte non-volatile memory for flight data storage.
1471 </p></li><li class="listitem"><p>
1472 RF interface for battery charging, configuration, and data recovery.
1473 </p></li><li class="listitem"><p>
1474 Support for Li-Po rechargeable batteries, using an external charger.
1475 </p></li><li class="listitem"><p>
1476 Uses Li-Po to fire e-matches, can be modified to support
1477 optional separate pyro battery if needed.
1478 </p></li><li class="listitem"><p>
1479 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube.
1480 </p></li></ul></div></div></div><div class="chapter" title="Chapter 11. FAQ"><div class="titlepage"><div><div><h2 class="title"><a name="idp3517088"></a>Chapter 11. FAQ</h2></div></div></div><p>
1481 TeleMetrum seems to shut off when disconnected from the
1482 computer. Make sure the battery is adequately charged. Remember the
1483 unit will pull more power than the USB port can deliver before the
1484 GPS enters "locked" mode. The battery charges best when TeleMetrum
1487 It's impossible to stop the TeleDongle when it's in "p" mode, I have
1488 to unplug the USB cable? Make sure you have tried to "escape out" of
1489 this mode. If this doesn't work the reboot procedure for the
1490 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
1491 outgoing buffer IF your "escape out" ('~~') does not work.
1492 At this point using either 'ao-view' (or possibly
1493 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
1496 The amber LED (on the TeleMetrum) lights up when both
1497 battery and USB are connected. Does this mean it's charging?
1498 Yes, the yellow LED indicates the charging at the 'regular' rate.
1499 If the led is out but the unit is still plugged into a USB port,
1500 then the battery is being charged at a 'trickle' rate.
1502 There are no "dit-dah-dah-dit" sound or lights like the manual mentions?
1503 That's the "pad" mode. Weak batteries might be the problem.
1504 It is also possible that the TeleMetrum is horizontal and the output
1505 is instead a "dit-dit" meaning 'idle'. For TeleMini, it's possible that
1506 it received a command packet which would have left it in "pad" mode.
1508 How do I save flight data?
1509 Live telemetry is written to file(s) whenever AltosUI is connected
1510 to the TeleDongle. The file area defaults to ~/TeleMetrum
1511 but is easily changed using the menus in AltosUI. The files that
1512 are written end in '.telem'. The after-flight
1513 data-dumped files will end in .eeprom and represent continuous data
1514 unlike the .telem files that are subject to losses
1515 along the RF data path.
1516 See the above instructions on what and how to save the eeprom stored
1517 data after physically retrieving your altimeter. Make sure to save
1518 the on-board data after each flight; while the TeleMetrum can store
1519 multiple flights, you never know when you'll lose the altimeter...
1520 </p></div><div class="appendix" title="Appendix A. Notes for Older Software"><div class="titlepage"><div><div><h2 class="title"><a name="idp2358816"></a>Appendix A. Notes for Older Software</h2></div></div></div><p>
1521 <span class="emphasis"><em>
1522 Before AltosUI was written, using Altus Metrum devices required
1523 some finesse with the Linux command line. There was a limited
1524 GUI tool, ao-view, which provided functionality similar to the
1525 Monitor Flight window in AltosUI, but everything else was a
1526 fairly 80's experience. This appendix includes documentation for
1527 using that software.
1530 Both TeleMetrum and TeleDongle can be directly communicated
1531 with using USB ports. The first thing you should try after getting
1532 both units plugged into to your computer's USB port(s) is to run
1533 'ao-list' from a terminal-window to see what port-device-name each
1534 device has been assigned by the operating system.
1535 You will need this information to access the devices via their
1536 respective on-board firmware and data using other command line
1537 programs in the AltOS software suite.
1539 TeleMini can be communicated with through a TeleDongle device
1540 over the radio link. When first booted, TeleMini listens for a
1541 TeleDongle device and if it receives a packet, it goes into
1542 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be
1543 launched. The easiest way to get it talking is to start the
1544 communication link on the TeleDongle and the power up the
1547 To access the device's firmware for configuration you need a terminal
1548 program such as you would use to talk to a modem. The software
1549 authors prefer using the program 'cu' which comes from the UUCP package
1550 on most Unix-like systems such as Linux. An example command line for
1551 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
1552 indicated from running the
1553 ao-list program. Another reasonable terminal program for Linux is
1554 'cutecom'. The default 'escape'
1555 character used by CU (i.e. the character you use to
1556 issue commands to cu itself instead of sending the command as input
1557 to the connected device) is a '~'. You will need this for use in
1558 only two different ways during normal operations. First is to exit
1559 the program by sending a '~.' which is called a 'escape-disconnect'
1560 and allows you to close-out from 'cu'. The
1561 second use will be outlined later.
1563 All of the Altus Metrum devices share the concept of a two level
1564 command set in their firmware.
1565 The first layer has several single letter commands. Once
1566 you are using 'cu' (or 'cutecom') sending (typing) a '?'
1567 returns a full list of these
1568 commands. The second level are configuration sub-commands accessed
1569 using the 'c' command, for
1570 instance typing 'c?' will give you this second level of commands
1571 (all of which require the
1572 letter 'c' to access). Please note that most configuration options
1573 are stored only in Flash memory; TeleDongle doesn't provide any storage
1574 for these options and so they'll all be lost when you unplug it.
1576 Try setting these configuration ('c' or second level menu) values. A good
1577 place to start is by setting your call sign. By default, the boards
1578 use 'N0CALL' which is cute, but not exactly legal!
1579 Spend a few minutes getting comfortable with the units, their
1580 firmware, and 'cu' (or possibly 'cutecom').
1581 For instance, try to send
1582 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
1583 Verify you can connect and disconnect from the units while in your
1584 terminal program by sending the escape-disconnect mentioned above.
1586 To set the radio frequency, use the 'c R' command to specify the
1587 radio transceiver configuration parameter. This parameter is computed
1588 using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
1589 the standard calibration reference frequency, 'S', (normally 434.550MHz):
1590 </p><pre class="programlisting">
1593 Round the result to the nearest integer value.
1594 As with all 'c' sub-commands, follow this with a 'c w' to write the
1595 change to the parameter block in the on-board flash on
1596 your altimeter board if you want the change to stay in place across reboots.
1598 To set the apogee delay, use the 'c d' command.
1599 As with all 'c' sub-commands, follow this with a 'c w' to write the
1600 change to the parameter block in the on-board DataFlash chip.
1602 To set the main deployment altitude, use the 'c m' command.
1603 As with all 'c' sub-commands, follow this with a 'c w' to write the
1604 change to the parameter block in the on-board DataFlash chip.
1606 To calibrate the radio frequency, connect the UHF antenna port to a
1607 frequency counter, set the board to 434.550MHz, and use the 'C'
1608 command to generate a CW carrier. Wait for the transmitter temperature
1609 to stabilize and the frequency to settle down.
1610 Then, divide 434.550 MHz by the
1611 measured frequency and multiply by the current radio cal value show
1612 in the 'c s' command. For an unprogrammed board, the default value
1613 is 1186611. Take the resulting integer and program it using the 'c f'
1614 command. Testing with the 'C' command again should show a carrier
1615 within a few tens of Hertz of the intended frequency.
1616 As with all 'c' sub-commands, follow this with a 'c w' to write the
1617 change to the parameter block in the on-board DataFlash chip.
1619 Note that the 'reboot' command, which is very useful on the altimeters,
1620 will likely just cause problems with the dongle. The *correct* way
1621 to reset the dongle is just to unplug and re-plug it.
1623 A fun thing to do at the launch site and something you can do while
1624 learning how to use these units is to play with the radio link access
1625 between an altimeter and the TeleDongle. Be aware that you *must* create
1626 some physical separation between the devices, otherwise the link will
1627 not function due to signal overload in the receivers in each device.
1629 Now might be a good time to take a break and read the rest of this
1630 manual, particularly about the two "modes" that the altimeters
1631 can be placed in. TeleMetrum uses the position of the device when booting
1632 up will determine whether the unit is in "pad" or "idle" mode. TeleMini
1633 enters "idle" mode when it receives a command packet within the first 5 seconds
1634 of being powered up, otherwise it enters "pad" mode.
1636 You can access an altimeter in idle mode from the TeleDongle's USB
1637 connection using the radio link
1638 by issuing a 'p' command to the TeleDongle. Practice connecting and
1639 disconnecting ('~~' while using 'cu') from the altimeter. If
1640 you cannot escape out of the "p" command, (by using a '~~' when in
1641 CU) then it is likely that your kernel has issues. Try a newer version.
1643 Using this radio link allows you to configure the altimeter, test
1644 fire e-matches and igniters from the flight line, check pyro-match
1645 continuity and so forth. You can leave the unit turned on while it
1646 is in 'idle mode' and then place the
1647 rocket vertically on the launch pad, walk away and then issue a
1648 reboot command. The altimeter will reboot and start sending data
1649 having changed to the "pad" mode. If the TeleDongle is not receiving
1650 this data, you can disconnect 'cu' from the TeleDongle using the
1651 procedures mentioned above and THEN connect to the TeleDongle from
1652 inside 'ao-view'. If this doesn't work, disconnect from the
1653 TeleDongle, unplug it, and try again after plugging it back in.
1655 In order to reduce the chance of accidental firing of pyrotechnic
1656 charges, the command to fire a charge is intentionally somewhat
1657 difficult to type, and the built-in help is slightly cryptic to
1658 prevent accidental echoing of characters from the help text back at
1659 the board from firing a charge. The command to fire the apogee
1660 drogue charge is 'i DoIt drogue' and the command to fire the main
1661 charge is 'i DoIt main'.
1663 On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
1664 and 'ao-view' will both auditorily announce and visually indicate
1666 Now you can launch knowing that you have a good data path and
1667 good satellite lock for flight data and recovery. Remember
1668 you MUST tell ao-view to connect to the TeleDongle explicitly in
1669 order for ao-view to be able to receive data.
1671 The altimeters provide RDF (radio direction finding) tones on
1672 the pad, during descent and after landing. These can be used to
1673 locate the rocket using a directional antenna; the signal
1674 strength providing an indication of the direction from receiver to rocket.
1676 TeleMetrum also provides GPS tracking data, which can further simplify
1677 locating the rocket once it has landed. (The last good GPS data
1678 received before touch-down will be on the data screen of 'ao-view'.)
1680 Once you have recovered the rocket you can download the eeprom
1681 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
1682 either a USB cable or over the radio link using TeleDongle.
1683 And by following the man page for 'ao-postflight' you can create
1684 various data output reports, graphs, and even KML data to see the
1685 flight trajectory in Google-earth. (Moving the viewing angle making
1686 sure to connect the yellow lines while in Google-earth is the proper
1689 As for ao-view.... some things are in the menu but don't do anything
1690 very useful. The developers have stopped working on ao-view to focus
1691 on a new, cross-platform ground station program. So ao-view may or
1692 may not be updated in the future. Mostly you just use
1693 the Log and Device menus. It has a wonderful display of the incoming
1694 flight data and I am sure you will enjoy what it has to say to you
1695 once you enable the voice output!
1696 </p></div><div class="appendix" title="Appendix B. Calibration"><div class="titlepage"><div><div><h2 class="title"><a name="idp2555760"></a>Appendix B. Calibration</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#idp1119368">1. Radio Frequency</a></span></dt><dt><span class="section"><a href="#idp3257080">2. TeleMetrum Accelerometer</a></span></dt></dl></div><p>
1697 There are only two calibrations required for a TeleMetrum board, and
1698 only one for TeleDongle and TeleMini. All boards are shipped from
1699 the factory pre-calibrated, but the procedures are documented here
1700 in case they are ever needed. Re-calibration is not supported by
1701 AltosUI, you must connect to the board with a serial terminal program
1702 and interact directly with the on-board command interpreter to effect
1704 </p><div class="section" title="1. Radio Frequency"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp1119368"></a>1. Radio Frequency</h2></div></div></div><p>
1705 The radio frequency is synthesized from a clock based on the 48 MHz
1706 crystal on the board. The actual frequency of this oscillator
1707 must be measured to generate a calibration constant. While our
1709 bandwidth is wide enough to allow boards to communicate even when
1710 their oscillators are not on exactly the same frequency, performance
1711 is best when they are closely matched.
1712 Radio frequency calibration requires a calibrated frequency counter.
1713 Fortunately, once set, the variation in frequency due to aging and
1714 temperature changes is small enough that re-calibration by customers
1715 should generally not be required.
1717 To calibrate the radio frequency, connect the UHF antenna port to a
1718 frequency counter, set the board to 434.550MHz, and use the 'C'
1719 command in the on-board command interpreter to generate a CW
1720 carrier. For TeleMetrum, this is best done over USB. For TeleMini,
1721 note that the only way to escape the 'C' command is via power cycle
1722 since the board will no longer be listening for commands once it
1723 starts generating a CW carrier.
1725 Wait for the transmitter temperature to stabilize and the frequency
1726 to settle down. Then, divide 434.550 MHz by the
1727 measured frequency and multiply by the current radio cal value show
1728 in the 'c s' command. For an unprogrammed board, the default value
1729 is 1186611. Take the resulting integer and program it using the 'c f'
1730 command. Testing with the 'C' command again should show a carrier
1731 within a few tens of Hertz of the intended frequency.
1732 As with all 'c' sub-commands, follow this with a 'c w' to write the
1733 change to the parameter block in the on-board DataFlash chip.
1735 Note that any time you re-do the radio frequency calibration, the
1736 radio frequency is reset to the default 434.550 Mhz. If you want
1737 to use another frequency, you will have to set that again after
1738 calibration is completed.
1739 </p></div><div class="section" title="2. TeleMetrum Accelerometer"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idp3257080"></a>2. TeleMetrum Accelerometer</h2></div></div></div><p>
1740 The TeleMetrum accelerometer we use has its own 5 volt power
1742 the output must be passed through a resistive voltage divider to match
1743 the input of our 3.3 volt ADC. This means that unlike the barometric
1744 sensor, the output of the acceleration sensor is not ratio-metric to
1745 the ADC converter, and calibration is required. Explicitly
1746 calibrating the accelerometers also allows us to load any device
1747 from a Freescale family that includes at least +/- 40g, 50g, 100g,
1748 and 200g parts. Using gravity,
1749 a simple 2-point calibration yields acceptable results capturing both
1750 the different sensitivities and ranges of the different accelerometer
1751 parts and any variation in power supply voltages or resistor values
1752 in the divider network.
1754 To calibrate the acceleration sensor, use the 'c a 0' command. You
1755 will be prompted to orient the board vertically with the UHF antenna
1756 up and press a key, then to orient the board vertically with the
1757 UHF antenna down and press a key. Note that the accuracy of this
1758 calibration depends primarily on how perfectly vertical and still
1759 the board is held during the cal process. As with all 'c'
1760 sub-commands, follow this with a 'c w' to write the
1761 change to the parameter block in the on-board DataFlash chip.
1763 The +1g and -1g calibration points are included in each telemetry
1764 frame and are part of the header stored in onboard flash to be
1765 downloaded after flight. We always store and return raw ADC
1766 samples for each sensor... so nothing is permanently "lost" or
1767 "damaged" if the calibration is poor.
1769 In the unlikely event an accel cal goes badly, it is possible
1770 that TeleMetrum may always come up in 'pad mode' and as such not be
1771 listening to either the USB or radio link. If that happens,
1772 there is a special hook in the firmware to force the board back
1773 in to 'idle mode' so you can re-do the cal. To use this hook, you
1774 just need to ground the SPI clock pin at power-on. This pin is
1775 available as pin 2 on the 8-pin companion connector, and pin 1 is
1776 ground. So either carefully install a fine-gauge wire jumper
1777 between the two pins closest to the index hole end of the 8-pin
1778 connector, or plug in the programming cable to the 8-pin connector
1779 and use a small screwdriver or similar to short the two pins closest
1780 to the index post on the 4-pin end of the programming cable, and
1781 power up the board. It should come up in 'idle mode' (two beeps),
1783 </p></div></div><div class="appendix" title="Appendix C. Release Notes"><div class="titlepage"><div><div><h2 class="title"><a name="idp2653672"></a>Appendix C. Release Notes</h2></div></div></div><span style="color: red"><xi:include></xi:include></span><p>
1784 Version 0.9.2 is an AltosUI bug-fix release, with no firmware changes.
1785 </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
1786 Fix plotting problems due to missing file in the Mac OS install image.
1787 </li><li class="listitem">
1788 Always read whole eeprom blocks, mark empty records invalid, display parsing errors to user.
1789 </li><li class="listitem">
1790 Add software version to Configure AltosUI dialog
1792 Version 0.9 adds a few new firmware features and accompanying
1793 AltosUI changes, along with new hardware support.
1794 </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
1795 Support for TeleMetrum v1.1 hardware. Sources for the flash
1796 memory part used in v1.0 dried up, so v1.1 uses a different part
1797 which required a new driver and support for explicit flight log
1799 </li><li class="listitem">
1800 Multiple flight log support. This stores more than one flight
1801 log in the on-board flash memory. It also requires the user to
1802 explicitly erase flights so that you won't lose flight logs just
1803 because you fly the same board twice in one day.
1804 </li><li class="listitem">
1805 Telemetry support for devices with serial number >=
1806 256. Previous versions used a telemetry packet format that
1807 provided only 8 bits for the device serial number. This change
1808 requires that both ends of the telemetry link be running the 0.9
1809 firmware or they will not communicate.
1811 Version 0.8 offers a major upgrade in the AltosUI
1812 interface. Significant new features include:
1813 </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
1814 Post-flight graphing tool. This lets you explore the behaviour
1815 of your rocket after flight with a scroll-able and zoom-able
1816 chart showing the altitude, speed and acceleration of the
1817 airframe along with events recorded by the flight computer. You
1818 can export graphs to PNG files, or print them directly.
1819 </li><li class="listitem">
1820 Real-time moving map which overlays the in-progress flight on
1821 satellite imagery fetched from Google Maps. This lets you see in
1822 pictures where your rocket has landed, allowing you to plan
1823 recovery activities more accurately.
1824 </li><li class="listitem">
1825 Wireless recovery system testing. Prep your rocket for flight
1826 and test fire the deployment charges to make sure things work as
1827 expected. All without threading wires through holes in your
1829 </li><li class="listitem">
1830 Optimized flight status displays. Each flight state now has it's
1831 own custom 'tab' in the flight monitoring window so you can
1832 focus on the most important details. Pre-flight, the system
1833 shows a set of red/green status indicators for battery voltage,
1834 apogee/main igniter continutity and GPS reception. Wait until
1835 they're all green and your rocket is ready for flight. There are
1836 also tabs for ascent, descent and landing along with the
1837 original tabular view of the data.
1838 </li><li class="listitem">
1839 Monitor multiple flights simultaneously. If you have more than
1840 one TeleDongle, you can monitor a flight with each one on the
1842 </li><li class="listitem">
1843 Automatic flight monitoring at startup. Plug TeleDongle into the
1844 machine before starting AltosUI and it will automatically
1845 connect to it and prepare to monitor a flight.
1846 </li><li class="listitem">
1847 Exports Google Earth flight tracks. Using the Keyhole Markup
1848 Language (.kml) file format, this provides a 3D view of your
1849 rocket flight through the Google Earth program.
1851 Version 0.7.1 is the first release containing our new cross-platform Java-based user interface. AltosUI can:
1852 </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
1853 Receive and log telemetry from a connected TeleDongle
1854 device. All data received is saved to log files named with the
1855 current date and the connected rocket serial and flight
1856 numbers. There is no mode in which telemetry data will not be
1858 </li><li class="listitem">
1859 Download logged data from TeleMetrum devices, either through a
1860 direct USB connection or over the air through a TeleDongle
1862 </li><li class="listitem">
1863 Configure a TeleMetrum device, setting the radio channel,
1864 callsign, apogee delay and main deploy height. This can be done
1865 through either a USB connection or over a radio link via a
1867 </li><li class="listitem">
1868 Replay a flight in real-time. This takes a saved telemetry log
1869 or eeprom download and replays it through the user interface so
1870 you can relive your favorite rocket flights.
1871 </li><li class="listitem">
1872 Reprogram Altus Metrum devices. Using an Altus Metrum device
1873 connected via USB, another Altus Metrum device can be
1874 reprogrammed using the supplied programming cable between the
1876 </li><li class="listitem">
1877 Export Flight data to a comma-separated-values file. This takes
1878 either telemetry or on-board flight data and generates data
1879 suitable for use in external applications. All data is exported
1880 using standard units so that no device-specific knowledge is
1881 needed to handle the data.
1882 </li><li class="listitem">
1883 Speak to you during the flight. Instead of spending the flight
1884 hunched over your laptop looking at the screen, enjoy the view
1885 while the computer tells you what’s going on up there. During
1886 ascent, you hear the current flight state and altitude
1887 information. During descent, you get azimuth, elevation and
1888 range information to try and help you find your rocket in the
1889 air. Once on the ground, the direction and distance are
1891 </li></ul></div></div></div></body></html>
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