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2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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5 <title>The Altus Metrum System</title>
6 <subtitle>An Owner's Manual for Altus Metrum Rocketry Electronics</subtitle>
9 <firstname>Bdale</firstname>
10 <surname>Garbee</surname>
13 <firstname>Keith</firstname>
14 <surname>Packard</surname>
17 <firstname>Bob</firstname>
18 <surname>Finch</surname>
21 <firstname>Anthony</firstname>
22 <surname>Towns</surname>
26 <holder>Bdale Garbee and Keith Packard</holder>
30 This document is released under the terms of the
31 <ulink url="http://creativecommons.org/licenses/by-sa/3.0/">
32 Creative Commons ShareAlike 3.0
39 <revnumber>1.3</revnumber>
40 <date>12 November 2013</date>
42 Updated for software version 1.3. Version 1.3 adds support
43 for TeleMega, TeleMetrum v2.0, TeleMini v2.0 and EasyMini
44 and fixes bugs in AltosUI and the AltOS firmware.
48 <revnumber>1.2.1</revnumber>
49 <date>21 May 2013</date>
51 Updated for software version 1.2. Version 1.2 adds support
52 for TeleBT and AltosDroid. It also adds a few minor features
53 and fixes bugs in AltosUI and the AltOS firmware.
57 <revnumber>1.2</revnumber>
58 <date>18 April 2013</date>
60 Updated for software version 1.2. Version 1.2 adds support
61 for MicroPeak and the MicroPeak USB interface.
65 <revnumber>1.1.1</revnumber>
66 <date>16 September 2012</date>
68 Updated for software version 1.1.1 Version 1.1.1 fixes a few
69 bugs found in version 1.1.
73 <revnumber>1.1</revnumber>
74 <date>13 September 2012</date>
76 Updated for software version 1.1. Version 1.1 has new
77 features but is otherwise compatible with version 1.0.
81 <revnumber>1.0</revnumber>
82 <date>24 August 2011</date>
84 Updated for software version 1.0. Note that 1.0 represents a
85 telemetry format change, meaning both ends of a link
86 (TeleMetrum/TeleMini and TeleDongle) must be updated or
87 communications will fail.
91 <revnumber>0.9</revnumber>
92 <date>18 January 2011</date>
94 Updated for software version 0.9. Note that 0.9 represents a
95 telemetry format change, meaning both ends of a link (TeleMetrum and
96 TeleDongle) must be updated or communications will fail.
100 <revnumber>0.8</revnumber>
101 <date>24 November 2010</date>
102 <revremark>Updated for software version 0.8 </revremark>
107 <title>Acknowledgments</title>
109 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing “The
110 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
111 Kit” which formed the basis of the original Getting Started chapter
112 in this manual. Bob was one of our first customers for a production
113 TeleMetrum, and his continued enthusiasm and contributions
114 are immensely gratifying and highly appreciated!
117 And thanks to Anthony (AJ) Towns for major contributions including
118 the AltosUI graphing and site map code and associated documentation.
119 Free software means that our customers and friends can become our
120 collaborators, and we certainly appreciate this level of
124 Have fun using these products, and we hope to meet all of you
125 out on the rocket flight line somewhere.
128 NAR #87103, TRA #12201
130 Keith Packard, KD7SQG
131 NAR #88757, TRA #12200
136 <title>Introduction and Overview</title>
138 Welcome to the Altus Metrum community! Our circuits and software reflect
139 our passion for both hobby rocketry and Free Software. We hope their
140 capabilities and performance will delight you in every way, but by
141 releasing all of our hardware and software designs under open licenses,
142 we also hope to empower you to take as active a role in our collective
146 The first device created for our community was TeleMetrum, a dual
147 deploy altimeter with fully integrated GPS and radio telemetry
148 as standard features, and a “companion interface” that will
149 support optional capabilities in the future. The latest version
150 of TeleMetrum, v2.0, has all of the same features but with
151 improved sensors and radio to offer increased performance.
154 Our second device was TeleMini, a dual deploy altimeter with
155 radio telemetry and radio direction finding. The first version
156 of this device was only 13mm by 38mm (½ inch by 1½ inches) and
157 could fit easily in an 18mm air-frame. The latest version, v2.0,
158 includes a beeper, USB data download and extended on-board
159 flight logging, along with an improved barometric sensor.
162 TeleMega is our most sophisticated device, including six pyro
163 channels (four of which are fully programmable), integrated GPS,
164 integrated gyroscopes for staging/air-start inhibit and high
165 performance telemetry.
168 EasyMini is a dual-deploy altimeter with logging and built-in
172 TeleDongle was our first ground station, providing a USB to RF
173 interfaces for communicating with the altimeters. Combined with
174 your choice of antenna and notebook computer, TeleDongle and our
175 associated user interface software form a complete ground
176 station capable of logging and displaying in-flight telemetry,
177 aiding rocket recovery, then processing and archiving flight
178 data for analysis and review.
181 For a slightly more portable ground station experience that also
182 provides direct rocket recovery support, TeleBT offers flight
183 monitoring and data logging using a Bluetooth™ connection between
184 the receiver and an Android device that has the AltosDroid
185 application installed from the Google Play store.
188 More products will be added to the Altus Metrum family over time, and
189 we currently envision that this will be a single, comprehensive manual
190 for the entire product family.
194 <title>Getting Started</title>
196 The first thing to do after you check the inventory of parts in your
197 “starter kit” is to charge the battery.
200 For TeleMetrum and TeleMega, the battery can be charged by plugging it into the
201 corresponding socket of the device and then using the USB
202 cable to plug the flight computer into your computer's USB socket. The
203 on-board circuitry will charge the battery whenever it is plugged
204 in, because the on-off switch does NOT control the
208 On TeleMetrum v1 boards, when the GPS chip is initially
209 searching for satellites, TeleMetrum will consume more current
210 than it pulls from the USB port, so the battery must be
211 attached in order to get satellite lock. Once GPS is locked,
212 the current consumption goes back down enough to enable charging
213 while running. So it's a good idea to fully charge the battery
214 as your first item of business so there is no issue getting and
215 maintaining satellite lock. The yellow charge indicator led
216 will go out when the battery is nearly full and the charger goes
217 to trickle charge. It can take several hours to fully recharge a
218 deeply discharged battery.
221 TeleMetrum v2.0 and TeleMega use a higher power battery charger,
222 allowing them to charge the battery while running the board at
223 maximum power. When the battery is charging, or when the board
224 is consuming a lot of power, the red LED will be lit. When the
225 battery is fully charged, the green LED will be lit. When the
226 battery is damaged or missing, both LEDs will be lit, which
230 The Lithium Polymer TeleMini and EasyMini battery can be charged by
231 disconnecting it from the board and plugging it into a
232 standalone battery charger such as the LipoCharger product
233 included in TeleMini Starter Kits, and connecting that via a USB
234 cable to a laptop or other USB power source.
237 You can also choose to use another battery with TeleMini v2.0
238 and EasyMini, anything supplying between 4 and 12 volts should
239 work fine (like a standard 9V battery), but if you are planning
240 to fire pyro charges, ground testing is required to verify that
241 the battery supplies enough current to fire your chosen e-matches.
244 The other active device in the starter kit is the TeleDongle USB to
245 RF interface. If you plug it in to your Mac or Linux computer it should
246 “just work”, showing up as a serial port device. Windows systems need
247 driver information that is part of the AltOS download to know that the
248 existing USB modem driver will work. We therefore recommend installing
249 our software before plugging in TeleDongle if you are using a Windows
250 computer. If you are using an older version of Linux and are having
251 problems, try moving to a fresher kernel (2.6.33 or newer).
254 Next you should obtain and install the AltOS software. The AltOS
255 distribution includes the AltosUI ground station program, current
257 images for all of the hardware, and a number of standalone
258 utilities that are rarely needed. Pre-built binary packages are
259 available for Linux, Microsoft Windows, and recent MacOSX
260 versions. Full source code and build instructions are also
261 available. The latest version may always be downloaded from
262 <ulink url="http://altusmetrum.org/AltOS"/>.
265 If you're using a TeleBT instead of the TeleDongle, you'll want to
266 install the AltosDroid application from the Google Play store on an
267 Android device. You don't need a data plan to use AltosDroid, but
268 without network access, the Map view will be less useful as it
269 won't contain any map data. You can also use TeleBT connected
270 over USB with your laptop computer; it acts exactly like a
271 TeleDongle. Anywhere this manual talks about TeleDongle, you can
272 also read that as 'and TeleBT when connected via USB'.
276 <title>Handling Precautions</title>
278 All Altus Metrum products are sophisticated electronic devices.
279 When handled gently and properly installed in an air-frame, they
280 will deliver impressive results. However, as with all electronic
281 devices, there are some precautions you must take.
284 The Lithium Polymer rechargeable batteries have an
285 extraordinary power density. This is great because we can fly with
286 much less battery mass than if we used alkaline batteries or previous
287 generation rechargeable batteries... but if they are punctured
288 or their leads are allowed to short, they can and will release their
290 Thus we recommend that you take some care when handling our batteries
291 and consider giving them some extra protection in your air-frame. We
292 often wrap them in suitable scraps of closed-cell packing foam before
293 strapping them down, for example.
296 The barometric sensors used on all of our flight computers are
297 sensitive to sunlight. In normal mounting situations, the baro sensor
298 and all of the other surface mount components
299 are “down” towards whatever the underlying mounting surface is, so
300 this is not normally a problem. Please consider this when designing an
301 installation in an air-frame with a see-through plastic payload bay. It
302 is particularly important to
303 consider this with TeleMini v1.0, both because the baro sensor is on the
304 “top” of the board, and because many model rockets with payload bays
305 use clear plastic for the payload bay! Replacing these with an opaque
306 cardboard tube, painting them, or wrapping them with a layer of masking
307 tape are all reasonable approaches to keep the sensor out of direct
311 The barometric sensor sampling port must be able to “breathe”,
312 both by not being covered by foam or tape or other materials that might
313 directly block the hole on the top of the sensor, and also by having a
314 suitable static vent to outside air.
317 As with all other rocketry electronics, Altus Metrum altimeters must
318 be protected from exposure to corrosive motor exhaust and ejection
323 <title>Altus Metrum Hardware</title>
325 <title>Overview</title>
327 Here's the full set of Altus Metrum products, both in
328 production and retired.
331 <title>Altus Metrum Electronics</title>
332 <?dbfo keep-together="always"?>
333 <tgroup cols='8' align='center' colsep='1' rowsep='1'>
334 <colspec align='center' colwidth='*' colname='Device'/>
335 <colspec align='center' colwidth='*' colname='Barometer'/>
336 <colspec align='center' colwidth='*' colname='Z-axis accelerometer'/>
337 <colspec align='center' colwidth='*' colname='GPS'/>
338 <colspec align='center' colwidth='*' colname='3D sensors'/>
339 <colspec align='center' colwidth='*' colname='Storage'/>
340 <colspec align='center' colwidth='*' colname='RF'/>
341 <colspec align='center' colwidth='*' colname='Battery'/>
344 <entry align='center'>Device</entry>
345 <entry align='center'>Barometer</entry>
346 <entry align='center'>Z-axis accelerometer</entry>
347 <entry align='center'>GPS</entry>
348 <entry align='center'>3D sensors</entry>
349 <entry align='center'>Storage</entry>
350 <entry align='center'>RF Output</entry>
351 <entry align='center'>Battery</entry>
356 <entry>TeleMetrum v1.0</entry>
357 <entry><para>MP3H6115 10km (33k')</para></entry>
358 <entry><para>MMA2202 50g</para></entry>
359 <entry>SkyTraq</entry>
366 <entry>TeleMetrum v1.1</entry>
367 <entry><para>MP3H6115 10km (33k')</para></entry>
368 <entry><para>MMA2202 50g</para></entry>
369 <entry>SkyTraq</entry>
376 <entry>TeleMetrum v1.2</entry>
377 <entry><para>MP3H6115 10km (33k')</para></entry>
378 <entry><para>ADXL78 70g</para></entry>
379 <entry>SkyTraq</entry>
386 <entry>TeleMetrum v2.0</entry>
387 <entry><para>MS5607 30km (100k')</para></entry>
388 <entry><para>MMA6555 102g</para></entry>
389 <entry>uBlox Max-7Q</entry>
396 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
397 <entry><para>MP3H6115 10km (33k')</para></entry>
406 <entry>TeleMini <?linebreak?>v2.0</entry>
407 <entry><para>MS5607 30km (100k')</para></entry>
413 <entry>3.7-12V</entry>
416 <entry>EasyMini <?linebreak?>v1.0</entry>
417 <entry><para>MS5607 30km (100k')</para></entry>
423 <entry>3.7-12V</entry>
426 <entry>TeleMega <?linebreak?>v1.0</entry>
427 <entry><para>MS5607 30km (100k')</para></entry>
428 <entry><para>MMA6555 102g</para></entry>
429 <entry>uBlox Max-7Q</entry>
430 <entry><para>MPU6000 HMC5883</para></entry>
439 <title>Altus Metrum Boards</title>
440 <?dbfo keep-together="always"?>
441 <tgroup cols='6' align='center' colsep='1' rowsep='1'>
442 <colspec align='center' colwidth='*' colname='Device'/>
443 <colspec align='center' colwidth='*' colname='Connectors'/>
444 <colspec align='center' colwidth='*' colname='Screw Terminals'/>
445 <colspec align='center' colwidth='*' colname='Width'/>
446 <colspec align='center' colwidth='*' colname='Length'/>
447 <colspec align='center' colwidth='*' colname='Tube Size'/>
450 <entry align='center'>Device</entry>
451 <entry align='center'>Connectors</entry>
452 <entry align='center'>Screw Terminals</entry>
453 <entry align='center'>Width</entry>
454 <entry align='center'>Length</entry>
455 <entry align='center'>Tube Size</entry>
460 <entry>TeleMetrum</entry>
464 Companion<?linebreak?>
468 <entry><para>Apogee pyro <?linebreak?>Main pyro <?linebreak?>Switch</para></entry>
469 <entry>1 inch (2.54cm)</entry>
470 <entry>2 ¾ inch (6.99cm)</entry>
471 <entry>29mm coupler</entry>
474 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
481 Apogee pyro <?linebreak?>
484 <entry>½ inch (1.27cm)</entry>
485 <entry>1½ inch (3.81cm)</entry>
486 <entry>18mm coupler</entry>
489 <entry>TeleMini <?linebreak?>v2.0</entry>
497 Apogee pyro <?linebreak?>
498 Main pyro <?linebreak?>
499 Battery <?linebreak?>
502 <entry>0.8 inch (2.03cm)</entry>
503 <entry>1½ inch (3.81cm)</entry>
504 <entry>24mm coupler</entry>
507 <entry>EasyMini</entry>
514 Apogee pyro <?linebreak?>
515 Main pyro <?linebreak?>
516 Battery <?linebreak?>
519 <entry>0.8 inch (2.03cm)</entry>
520 <entry>1½ inch (3.81cm)</entry>
521 <entry>24mm coupler</entry>
524 <entry>TeleMega</entry>
528 Companion<?linebreak?>
533 Apogee pyro <?linebreak?>
534 Main pyro<?linebreak?>
535 Pyro A-D<?linebreak?>
539 <entry>1¼ inch (3.18cm)</entry>
540 <entry>3¼ inch (8.26cm)</entry>
541 <entry>38mm coupler</entry>
548 <title>TeleMetrum</title>
551 <imagedata fileref="telemetrum-v1.1-thside.jpg" width="5.5in" scalefit="1"/>
555 TeleMetrum is a 1 inch by 2¾ inch circuit board. It was designed to
556 fit inside coupler for 29mm air-frame tubing, but using it in a tube that
557 small in diameter may require some creativity in mounting and wiring
558 to succeed! The presence of an accelerometer means TeleMetrum should
559 be aligned along the flight axis of the airframe, and by default the ¼
560 wave UHF wire antenna should be on the nose-cone end of the board. The
561 antenna wire is about 7 inches long, and wiring for a power switch and
562 the e-matches for apogee and main ejection charges depart from the
563 fin can end of the board, meaning an ideal “simple” avionics
564 bay for TeleMetrum should have at least 10 inches of interior length.
568 <title>TeleMini</title>
571 <imagedata fileref="telemini-v1-top.jpg" width="5.5in" scalefit="1"/>
575 TeleMini v1.0 is ½ inches by 1½ inches. It was
576 designed to fit inside an 18mm air-frame tube, but using it in
577 a tube that small in diameter may require some creativity in
578 mounting and wiring to succeed! Since there is no
579 accelerometer, TeleMini can be mounted in any convenient
580 orientation. The default ¼ wave UHF wire antenna attached to
581 the center of one end of the board is about 7 inches long. Two
582 wires for the power switch are connected to holes in the
583 middle of the board. Screw terminals for the e-matches for
584 apogee and main ejection charges depart from the other end of
585 the board, meaning an ideal “simple” avionics bay for TeleMini
586 should have at least 9 inches of interior length.
590 <imagedata fileref="telemini-v2-top.jpg" width="5.5in" scalefit="1"/>
594 TeleMini v2.0 is 0.8 inches by 1½ inches. It adds more
595 on-board data logging memory, a built-in USB connector and
596 screw terminals for the battery and power switch. The larger
597 board fits in a 24mm coupler. There's also a battery connector
598 for a LiPo battery if you want to use one of those.
602 <title>EasyMini</title>
605 <imagedata fileref="easymini-top.jpg" width="5.5in" scalefit="1"/>
609 EasyMini is built on a 0.8 inch by 1½ inch circuit board. It's
610 designed to fit in a 24mm coupler tube. The connectors and
611 screw terminals match TeleMini v2.0, so you can easily swap between
612 EasyMini and TeleMini.
616 <title>TeleMega</title>
619 <imagedata fileref="telemega-v1.0-top.jpg" width="5.5in" scalefit="1"/>
623 TeleMega is a 1¼ inch by 3¼ inch circuit board. It was
624 designed to easily fit in a 38mm coupler. Like TeleMetrum,
625 TeleMega has an accelerometer and so it must be mounted so that
626 the board is aligned with the flight axis. It can be mounted
627 either antenna up or down.
631 <title>Flight Data Recording</title>
633 Each flight computer logs data at 100 samples per second
634 during ascent and 10 samples per second during descent, except
635 for TeleMini v1.0, which records ascent at 10 samples per
636 second and descent at 1 sample per second. Data are logged to
637 an on-board flash memory part, which can be partitioned into
638 several equal-sized blocks, one for each flight.
641 <title>Data Storage on Altus Metrum altimeters</title>
642 <?dbfo keep-together="always"?>
643 <tgroup cols='4' align='center' colsep='1' rowsep='1'>
644 <colspec align='center' colwidth='*' colname='Device'/>
645 <colspec align='center' colwidth='*' colname='Bytes per sample'/>
646 <colspec align='center' colwidth='*' colname='Total storage'/>
647 <colspec align='center' colwidth='*' colname='Minutes of
651 <entry align='center'>Device</entry>
652 <entry align='center'>Bytes per Sample</entry>
653 <entry align='center'>Total Storage</entry>
654 <entry align='center'>Minutes at Full Rate</entry>
659 <entry>TeleMetrum v1.0</entry>
665 <entry>TeleMetrum v1.1 v1.2</entry>
671 <entry>TeleMetrum v2.0</entry>
677 <entry>TeleMini v1.0</entry>
683 <entry>TeleMini v2.0</entry>
689 <entry>EasyMini</entry>
695 <entry>TeleMega</entry>
704 The on-board flash is partitioned into separate flight logs,
705 each of a fixed maximum size. Increase the maximum size of
706 each log and you reduce the number of flights that can be
707 stored. Decrease the size and you can store more flights.
710 Configuration data is also stored in the flash memory on
711 TeleMetrum v1.x, TeleMini and EasyMini. This consumes 64kB
712 of flash space. This configuration space is not available
713 for storing flight log data. TeleMetrum v2.0 and TeleMega
714 store configuration data in a bit of eeprom available within
715 the processor chip, leaving that space available in flash for
719 To compute the amount of space needed for a single flight, you
720 can multiply the expected ascent time (in seconds) by 100
721 times bytes-per-sample, multiply the expected descent time (in
722 seconds) by 10 times the bytes per sample and add the two
723 together. That will slightly under-estimate the storage (in
724 bytes) needed for the flight. For instance, a TeleMetrum v2.0 flight spending
725 20 seconds in ascent and 150 seconds in descent will take
726 about (20 * 1600) + (150 * 160) = 56000 bytes of storage. You
727 could store dozens of these flights in the on-board flash.
730 The default size allows for several flights on each flight
731 computer, except for TeleMini v1.0, which only holds data for a
732 single flight. You can adjust the size.
735 Altus Metrum flight computers will not overwrite existing
736 flight data, so be sure to download flight data and erase it
737 from the flight computer before it fills up. The flight
738 computer will still successfully control the flight even if it
739 cannot log data, so the only thing you will lose is the data.
743 <title>Installation</title>
745 A typical installation involves attaching
746 only a suitable battery, a single pole switch for
747 power on/off, and two pairs of wires connecting e-matches for the
748 apogee and main ejection charges. All Altus Metrum products are
749 designed for use with single-cell batteries with 3.7 volts
750 nominal. TeleMini v2.0 and EasyMini may also be used with other
751 batteries as long as they supply between 4 and 12 volts.
754 The battery connectors are a standard 2-pin JST connector and
755 match batteries sold by Spark Fun. These batteries are
756 single-cell Lithium Polymer batteries that nominally provide 3.7
757 volts. Other vendors sell similar batteries for RC aircraft
758 using mating connectors, however the polarity for those is
759 generally reversed from the batteries used by Altus Metrum
760 products. In particular, the Tenergy batteries supplied for use
761 in Featherweight flight computers are not compatible with Altus
762 Metrum flight computers or battery chargers. <emphasis>Check
763 polarity and voltage before connecting any battery not purchased
764 from Altus Metrum or Spark Fun.</emphasis>
767 By default, we use the unregulated output of the battery directly
768 to fire ejection charges. This works marvelously with standard
769 low-current e-matches like the J-Tek from MJG Technologies, and with
770 Quest Q2G2 igniters. However, if you want or need to use a separate
771 pyro battery, check out the “External Pyro Battery” section in this
772 manual for instructions on how to wire that up. The altimeters are
773 designed to work with an external pyro battery of no more than 15 volts.
777 Ejection charges are wired directly to the screw terminal block
778 at the aft end of the altimeter. You'll need a very small straight
779 blade screwdriver for these screws, such as you might find in a
780 jeweler's screwdriver set.
783 Except for TeleMini v1.0, the flight computers also use the
784 screw terminal block for the power switch leads. On TeleMini v1.0,
785 the power switch leads are soldered directly to the board and
786 can be connected directly to a switch.
789 For most air-frames, the integrated antennas are more than
790 adequate. However, if you are installing in a carbon-fiber or
791 metal electronics bay which is opaque to RF signals, you may need to
792 use off-board external antennas instead. In this case, you can
793 replace the stock UHF antenna wire with an edge-launched SMA connector,
794 and, on TeleMetrum v1, you can unplug the integrated GPS
795 antenna and select an appropriate off-board GPS antenna with
796 cable terminating in a U.FL connector.
801 <title>System Operation</title>
803 <title>Firmware Modes </title>
805 The AltOS firmware build for the altimeters has two
806 fundamental modes, “idle” and “flight”. Which of these modes
807 the firmware operates in is determined at start up time. For
808 TeleMetrum and TeleMega, which have accelerometers, the mode is
809 controlled by the orientation of the
810 rocket (well, actually the board, of course...) at the time
811 power is switched on. If the rocket is “nose up”, then
812 the flight computer assumes it's on a rail or rod being prepared for
813 launch, so the firmware chooses flight mode. However, if the
814 rocket is more or less horizontal, the firmware instead enters
815 idle mode. Since TeleMini v2.0 and EasyMini don't have an
816 accelerometer we can use to determine orientation, “idle” mode
817 is selected if the board is connected via USB to a computer,
818 otherwise the board enters “flight” mode. TeleMini v1.0
819 selects “idle” mode if it receives a command packet within the
820 first five seconds of operation.
823 At power on, you will hear three beeps or see three flashes
824 (“S” in Morse code for start up) and then a pause while
825 the altimeter completes initialization and self test, and decides
826 which mode to enter next.
829 In flight or “pad” mode, the altimeter engages the flight
830 state machine, goes into transmit-only mode to
831 send telemetry, and waits for launch to be detected.
832 Flight mode is indicated by an “di-dah-dah-dit” (“P” for pad)
833 on the beeper or lights, followed by beeps or flashes
834 indicating the state of the pyrotechnic igniter continuity.
835 One beep/flash indicates apogee continuity, two beeps/flashes
836 indicate main continuity, three beeps/flashes indicate both
837 apogee and main continuity, and one longer “brap” sound or
838 rapidly alternating lights indicates no continuity. For a
839 dual deploy flight, make sure you're getting three beeps or
840 flashes before launching! For apogee-only or motor eject
841 flights, do what makes sense.
844 If idle mode is entered, you will hear an audible “di-dit” or
845 see two short flashes (“I” for idle), and the flight state
846 machine is disengaged, thus no ejection charges will fire.
847 The altimeters also listen for the radio link when in idle
848 mode for requests sent via TeleDongle. Commands can be issued
849 in idle mode over either USB or the radio link
850 equivalently. TeleMini v1.0 only has the radio link. Idle
851 mode is useful for configuring the altimeter, for extracting
852 data from the on-board storage chip after flight, and for
853 ground testing pyro charges.
856 One “neat trick” of particular value when TeleMetrum or TeleMega are used with
857 very large air-frames, is that you can power the board up while the
858 rocket is horizontal, such that it comes up in idle mode. Then you can
859 raise the air-frame to launch position, and issue a 'reset' command
860 via TeleDongle over the radio link to cause the altimeter to reboot and
861 come up in flight mode. This is much safer than standing on the top
862 step of a rickety step-ladder or hanging off the side of a launch
863 tower with a screw-driver trying to turn on your avionics before
867 TeleMini v1.0 is configured solely via the radio link. Of course, that
868 means you need to know the TeleMini radio configuration values
869 or you won't be able to communicate with it. For situations
870 when you don't have the radio configuration values, TeleMini v1.0
871 offers an 'emergency recovery' mode. In this mode, TeleMini is
872 configured as follows:
876 Sets the radio frequency to 434.550MHz
881 Sets the radio calibration back to the factory value.
886 Sets the callsign to N0CALL
891 Does not go to 'pad' mode after five seconds.
897 To get into 'emergency recovery' mode, first find the row of
898 four small holes opposite the switch wiring. Using a short
899 piece of small gauge wire, connect the outer two holes
900 together, then power TeleMini up. Once the red LED is lit,
901 disconnect the wire and the board should signal that it's in
902 'idle' mode after the initial five second startup period.
908 TeleMetrum and TeleMega include a complete GPS receiver. A
909 complete explanation of how GPS works is beyond the scope of
910 this manual, but the bottom line is that the GPS receiver
911 needs to lock onto at least four satellites to obtain a solid
912 3 dimensional position fix and know what time it is.
915 The flight computers provide backup power to the GPS chip any time a
916 battery is connected. This allows the receiver to “warm start” on
917 the launch rail much faster than if every power-on were a GPS
918 “cold start”. In typical operations, powering up
919 on the flight line in idle mode while performing final air-frame
920 preparation will be sufficient to allow the GPS receiver to cold
921 start and acquire lock. Then the board can be powered down during
922 RSO review and installation on a launch rod or rail. When the board
923 is turned back on, the GPS system should lock very quickly, typically
924 long before igniter installation and return to the flight line are
929 <title>Controlling An Altimeter Over The Radio Link</title>
931 One of the unique features of the Altus Metrum system is the
932 ability to create a two way command link between TeleDongle
933 and an altimeter using the digital radio transceivers
934 built into each device. This allows you to interact with the
935 altimeter from afar, as if it were directly connected to the
939 Any operation which can be performed with a flight computer can
940 either be done with the device directly connected to the
941 computer via the USB cable, or through the radio
942 link. TeleMini v1.0 doesn't provide a USB connector and so it is
943 always communicated with over radio. Select the appropriate
944 TeleDongle device when the list of devices is presented and
945 AltosUI will interact with an altimeter over the radio link.
948 One oddity in the current interface is how AltosUI selects the
949 frequency for radio communications. Instead of providing
950 an interface to specifically configure the frequency, it uses
951 whatever frequency was most recently selected for the target
952 TeleDongle device in Monitor Flight mode. If you haven't ever
953 used that mode with the TeleDongle in question, select the
954 Monitor Flight button from the top level UI, and pick the
955 appropriate TeleDongle device. Once the flight monitoring
956 window is open, select the desired frequency and then close it
957 down again. All radio communications will now use that frequency.
962 Save Flight Data—Recover flight data from the rocket without
968 Configure altimeter apogee delays, main deploy heights
969 and additional pyro event conditions
970 to respond to changing launch conditions. You can also
971 'reboot' the altimeter. Use this to remotely enable the
972 flight computer by turning TeleMetrum or TeleMega on in “idle” mode,
973 then once the air-frame is oriented for launch, you can
974 reboot the altimeter and have it restart in pad mode
975 without having to climb the scary ladder.
980 Fire Igniters—Test your deployment charges without snaking
981 wires out through holes in the air-frame. Simply assemble the
982 rocket as if for flight with the apogee and main charges
983 loaded, then remotely command the altimeter to fire the
989 Operation over the radio link for configuring an altimeter, ground
990 testing igniters, and so forth uses the same RF frequencies as flight
991 telemetry. To configure the desired TeleDongle frequency, select
992 the monitor flight tab, then use the frequency selector and
993 close the window before performing other desired radio operations.
996 The flight computers only enable radio commanding in 'idle' mode.
997 TeleMetrum and TeleMega use the accelerometer to detect which orientation they
998 start up in, so make sure you have the flight computer lying horizontally when you turn
999 it on. Otherwise, it will start in 'pad' mode ready for
1000 flight, and will not be listening for command packets from TeleDongle.
1003 TeleMini listens for a command packet for five seconds after
1004 first being turned on, if it doesn't hear anything, it enters
1005 'pad' mode, ready for flight and will no longer listen for
1006 command packets. The easiest way to connect to TeleMini is to
1007 initiate the command and select the TeleDongle device. At this
1008 point, the TeleDongle will be attempting to communicate with
1009 the TeleMini. Now turn TeleMini on, and it should immediately
1010 start communicating with the TeleDongle and the desired
1011 operation can be performed.
1014 You can monitor the operation of the radio link by watching the
1015 lights on the devices. The red LED will flash each time a packet
1016 is transmitted, while the green LED will light up on TeleDongle when
1017 it is waiting to receive a packet from the altimeter.
1021 <title>Ground Testing </title>
1023 An important aspect of preparing a rocket using electronic deployment
1024 for flight is ground testing the recovery system. Thanks
1025 to the bi-directional radio link central to the Altus Metrum system,
1026 this can be accomplished in a TeleMega, TeleMetrum or TeleMini equipped rocket
1027 with less work than you may be accustomed to with other systems. It
1031 Just prep the rocket for flight, then power up the altimeter
1032 in “idle” mode (placing air-frame horizontal for TeleMetrum or TeleMega, or
1033 selecting the Configure Altimeter tab for TeleMini). This will cause
1034 the firmware to go into “idle” mode, in which the normal flight
1035 state machine is disabled and charges will not fire without
1036 manual command. You can now command the altimeter to fire the apogee
1037 or main charges from a safe distance using your computer and
1038 TeleDongle and the Fire Igniter tab to complete ejection testing.
1042 <title>Radio Link </title>
1044 Our flight computers all incorporate an RF transceiver, but
1045 it's not a full duplex system... each end can only be transmitting or
1046 receiving at any given moment. So we had to decide how to manage the
1050 By design, the altimeter firmware listens for the radio link when
1051 it's in “idle mode”, which
1052 allows us to use the radio link to configure the rocket, do things like
1053 ejection tests, and extract data after a flight without having to
1054 crack open the air-frame. However, when the board is in “flight
1055 mode”, the altimeter only
1056 transmits and doesn't listen at all. That's because we want to put
1057 ultimate priority on event detection and getting telemetry out of
1059 the radio in case the rocket crashes and we aren't able to extract
1063 We don't generally use a 'normal packet radio' mode like APRS
1064 because they're just too inefficient. The GFSK modulation we
1065 use is FSK with the base-band pulses passed through a Gaussian
1066 filter before they go into the modulator to limit the
1067 transmitted bandwidth. When combined with forward error
1068 correction and interleaving, this allows us to have a very
1069 robust 19.2 kilobit data link with only 10-40 milliwatts of
1070 transmit power, a whip antenna in the rocket, and a hand-held
1071 Yagi on the ground. We've had flights to above 21k feet AGL
1072 with great reception, and calculations suggest we should be
1073 good to well over 40k feet AGL with a 5-element yagi on the
1074 ground with our 10mW units and over 100k feet AGL with the
1075 40mW devices. We hope to fly boards to higher altitudes over
1076 time, and would of course appreciate customer feedback on
1077 performance in higher altitude flights!
1080 TeleMetrum v2.0 and TeleMega can send APRS if desired, and the
1081 interval between APRS packets can be configured. As each APRS
1082 packet takes a full second to transmit, we recommend an
1083 interval of at least 5 seconds to avoid consuming too much
1084 battery power or radio channel bandwidth.
1088 <title>Configurable Parameters</title>
1090 Configuring an Altus Metrum altimeter for flight is very
1091 simple. Even on our baro-only TeleMini and EasyMini boards, the use of a Kalman
1092 filter means there is no need to set a “mach delay”. The few
1093 configurable parameters can all be set using AltosUI over USB or
1094 or radio link via TeleDongle.
1097 <title>Radio Frequency</title>
1099 Altus Metrum boards support radio frequencies in the 70cm
1100 band. By default, the configuration interface provides a
1101 list of 10 “standard” frequencies in 100kHz channels starting at
1102 434.550MHz. However, the firmware supports use of
1103 any 50kHz multiple within the 70cm band. At any given
1104 launch, we highly recommend coordinating when and by whom each
1105 frequency will be used to avoid interference. And of course, both
1106 altimeter and TeleDongle must be configured to the same
1107 frequency to successfully communicate with each other.
1111 <title>Apogee Delay</title>
1113 Apogee delay is the number of seconds after the altimeter detects flight
1114 apogee that the drogue charge should be fired. In most cases, this
1115 should be left at the default of 0. However, if you are flying
1116 redundant electronics such as for an L3 certification, you may wish
1117 to set one of your altimeters to a positive delay so that both
1118 primary and backup pyrotechnic charges do not fire simultaneously.
1121 The Altus Metrum apogee detection algorithm fires exactly at
1122 apogee. If you are also flying an altimeter like the
1123 PerfectFlite MAWD, which only supports selecting 0 or 1
1124 seconds of apogee delay, you may wish to set the MAWD to 0
1125 seconds delay and set the TeleMetrum to fire your backup 2
1126 or 3 seconds later to avoid any chance of both charges
1127 firing simultaneously. We've flown several air-frames this
1128 way quite happily, including Keith's successful L3 cert.
1132 <title>Main Deployment Altitude</title>
1134 By default, the altimeter will fire the main deployment charge at an
1135 elevation of 250 meters (about 820 feet) above ground. We think this
1136 is a good elevation for most air-frames, but feel free to change this
1137 to suit. In particular, if you are flying two altimeters, you may
1139 deployment elevation for the backup altimeter to be something lower
1140 than the primary so that both pyrotechnic charges don't fire
1145 <title>Maximum Flight Log</title>
1147 Changing this value will set the maximum amount of flight
1148 log storage that an individual flight will use. The
1149 available storage is divided into as many flights of the
1150 specified size as can fit in the available space. You can
1151 download and erase individual flight logs. If you fill up
1152 the available storage, future flights will not get logged
1153 until you erase some of the stored ones.
1156 Even though our flight computers (except TeleMini v1.0) can store
1157 multiple flights, we strongly recommend downloading and saving
1158 flight data after each flight.
1162 <title>Ignite Mode</title>
1164 Instead of firing one charge at apogee and another charge at
1165 a fixed height above the ground, you can configure the
1166 altimeter to fire both at apogee or both during
1167 descent. This was added to support an airframe Bdale designed that
1168 had two altimeters, one in the fin can and one in the nose.
1171 Providing the ability to use both igniters for apogee or
1172 main allows some level of redundancy without needing two
1173 flight computers. In Redundant Apogee or Redundant Main
1174 mode, the two charges will be fired two seconds apart.
1178 <title>Pad Orientation</title>
1180 TeleMetrum and TeleMega measure acceleration along the axis
1181 of the board. Which way the board is oriented affects the
1182 sign of the acceleration value. Instead of trying to guess
1183 which way the board is mounted in the air frame, the
1184 altimeter must be explicitly configured for either Antenna
1185 Up or Antenna Down. The default, Antenna Up, expects the end
1186 of the board connected to the 70cm antenna to be nearest the
1187 nose of the rocket, with the end containing the screw
1188 terminals nearest the tail.
1192 <title>Configurable Pyro Channels</title>
1194 In addition to the usual Apogee and Main pyro channels,
1195 TeleMega has four additional channels that can be configured
1196 to activate when various flight conditions are
1197 satisfied. You can select as many conditions as necessary;
1198 all of them must be met in order to activate the
1199 channel. The conditions available are:
1204 Acceleration away from the ground. Select a value, and
1205 then choose whether acceleration should be above or
1206 below that value. Acceleration is positive upwards, so
1207 accelerating towards the ground would produce negative
1208 numbers. Acceleration during descent is noisy and
1209 inaccurate, so be careful when using it during these
1210 phases of the flight.
1215 Vertical speed. Select a value, and then choose whether
1216 vertical speed should be above or below that
1217 value. Speed is positive upwards, so moving towards the
1218 ground would produce negative numbers. Speed during
1219 descent is a bit noisy and so be careful when using it
1220 during these phases of the flight.
1225 Height. Select a value, and then choose whether the
1226 height above the launch pad should be above or below
1232 Orientation. TeleMega contains a 3-axis gyroscope and
1233 accelerometer which is used to measure the current
1234 angle. Note that this angle is not the change in angle
1235 from the launch pad, but rather absolute relative to
1236 gravity; the 3-axis accelerometer is used to compute the
1237 angle of the rocket on the launch pad and initialize the
1238 system. Because this value is computed by integrating
1239 rate gyros, it gets progressively less accurate as the
1240 flight goes on. It should have an accumulated error of
1241 less than 0.2°/second (after 10 seconds of flight, the
1242 error should be less than 2°).
1245 The usual use of the orientation configuration is to
1246 ensure that the rocket is traveling mostly upwards when
1247 deciding whether to ignite air starts or additional
1248 stages. For that, choose a reasonable maximum angle
1249 (like 20°) and set the motor igniter to require an angle
1250 of less than that value.
1255 Flight Time. Time since boost was detected. Select a
1256 value and choose whether to activate the pyro channel
1257 before or after that amount of time.
1262 Ascending. A simple test saying whether the rocket is
1263 going up or not. This is exactly equivalent to testing
1264 whether the speed is > 0.
1269 Descending. A simple test saying whether the rocket is
1270 going down or not. This is exactly equivalent to testing
1271 whether the speed is < 0.
1276 After Motor. The flight software counts each time the
1277 rocket starts accelerating (presumably due to a motor or
1278 motors igniting). Use this value to count ignitions for
1279 multi-staged or multi-airstart launches.
1284 Delay. This value doesn't perform any checks, instead it
1285 inserts a delay between the time when the other
1286 parameters become true and when the pyro channel is
1292 Flight State. The flight software tracks the flight
1293 through a sequence of states:
1297 Boost. The motor has lit and the rocket is
1298 accelerating upwards.
1303 Fast. The motor has burned out and the rocket is
1304 descellerating, but it is going faster than 200m/s.
1309 Coast. The rocket is still moving upwards and
1310 decelerating, but the speed is less than 200m/s.
1315 Drogue. The rocket has reached apogee and is heading
1316 back down, but is above the configured Main
1322 Main. The rocket is still descending, and is below
1328 Landed. The rocket is no longer moving.
1334 You can select a state to limit when the pyro channel
1335 may activate; note that the check is based on when the
1336 rocket transitions <emphasis>into</emphasis> the state, and so checking for
1337 “greater than Boost” means that the rocket is currently
1338 in boost or some later state.
1341 When a motor burns out, the rocket enters either Fast or
1342 Coast state (depending on how fast it is moving). If the
1343 computer detects upwards acceleration again, it will
1344 move back to Boost state.
1354 <title>AltosUI</title>
1356 The AltosUI program provides a graphical user interface for
1357 interacting with the Altus Metrum product family. AltosUI can
1358 monitor telemetry data, configure devices and many other
1359 tasks. The primary interface window provides a selection of
1360 buttons, one for each major activity in the system. This chapter
1361 is split into sections, each of which documents one of the tasks
1362 provided from the top-level toolbar.
1365 <title>Monitor Flight</title>
1366 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
1368 Selecting this item brings up a dialog box listing all of the
1369 connected TeleDongle devices. When you choose one of these,
1370 AltosUI will create a window to display telemetry data as
1371 received by the selected TeleDongle device.
1374 All telemetry data received are automatically recorded in
1375 suitable log files. The name of the files includes the current
1376 date and rocket serial and flight numbers.
1379 The radio frequency being monitored by the TeleDongle device is
1380 displayed at the top of the window. You can configure the
1381 frequency by clicking on the frequency box and selecting the desired
1382 frequency. AltosUI remembers the last frequency selected for each
1383 TeleDongle and selects that automatically the next time you use
1387 Below the TeleDongle frequency selector, the window contains a few
1388 significant pieces of information about the altimeter providing
1389 the telemetry data stream:
1393 <para>The configured call-sign</para>
1396 <para>The device serial number</para>
1399 <para>The flight number. Each altimeter remembers how many
1405 The rocket flight state. Each flight passes through several
1406 states including Pad, Boost, Fast, Coast, Drogue, Main and
1412 The Received Signal Strength Indicator value. This lets
1413 you know how strong a signal TeleDongle is receiving. The
1414 radio inside TeleDongle operates down to about -99dBm;
1415 weaker signals may not be receivable. The packet link uses
1416 error detection and correction techniques which prevent
1417 incorrect data from being reported.
1422 The age of the displayed data, in seconds since the last
1423 successfully received telemetry packet. In normal operation
1424 this will stay in the low single digits. If the number starts
1425 counting up, then you are no longer receiving data over the radio
1426 link from the flight computer.
1431 Finally, the largest portion of the window contains a set of
1432 tabs, each of which contain some information about the rocket.
1433 They're arranged in 'flight order' so that as the flight
1434 progresses, the selected tab automatically switches to display
1435 data relevant to the current state of the flight. You can select
1436 other tabs at any time. The final 'table' tab displays all of
1437 the raw telemetry values in one place in a spreadsheet-like format.
1440 <title>Launch Pad</title>
1442 The 'Launch Pad' tab shows information used to decide when the
1443 rocket is ready for flight. The first elements include red/green
1444 indicators, if any of these is red, you'll want to evaluate
1445 whether the rocket is ready to launch:
1448 <term>Battery Voltage</term>
1451 This indicates whether the Li-Po battery powering the
1452 flight computer has sufficient charge to last for
1453 the duration of the flight. A value of more than
1454 3.8V is required for a 'GO' status.
1459 <term>Apogee Igniter Voltage</term>
1462 This indicates whether the apogee
1463 igniter has continuity. If the igniter has a low
1464 resistance, then the voltage measured here will be close
1465 to the Li-Po battery voltage. A value greater than 3.2V is
1466 required for a 'GO' status.
1471 <term>Main Igniter Voltage</term>
1474 This indicates whether the main
1475 igniter has continuity. If the igniter has a low
1476 resistance, then the voltage measured here will be close
1477 to the Li-Po battery voltage. A value greater than 3.2V is
1478 required for a 'GO' status.
1483 <term>On-board Data Logging</term>
1486 This indicates whether there is
1487 space remaining on-board to store flight data for the
1488 upcoming flight. If you've downloaded data, but failed
1489 to erase flights, there may not be any space
1490 left. Most of our flight computers can store multiple
1491 flights, depending on the configured maximum flight log
1492 size. TeleMini v1.0 stores only a single flight, so it
1494 downloaded and erased after each flight to capture
1495 data. This only affects on-board flight logging; the
1496 altimeter will still transmit telemetry and fire
1497 ejection charges at the proper times even if the flight
1498 data storage is full.
1503 <term>GPS Locked</term>
1506 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
1507 currently able to compute position information. GPS requires
1508 at least 4 satellites to compute an accurate position.
1513 <term>GPS Ready</term>
1516 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
1517 10 consecutive positions without losing lock. This ensures
1518 that the GPS receiver has reliable reception from the
1526 The Launchpad tab also shows the computed launch pad position
1527 and altitude, averaging many reported positions to improve the
1528 accuracy of the fix.
1532 <title>Ascent</title>
1534 This tab is shown during Boost, Fast and Coast
1535 phases. The information displayed here helps monitor the
1536 rocket as it heads towards apogee.
1539 The height, speed and acceleration are shown along with the
1540 maximum values for each of them. This allows you to quickly
1541 answer the most commonly asked questions you'll hear during
1545 The current latitude and longitude reported by the GPS are
1546 also shown. Note that under high acceleration, these values
1547 may not get updated as the GPS receiver loses position
1548 fix. Once the rocket starts coasting, the receiver should
1549 start reporting position again.
1552 Finally, the current igniter voltages are reported as in the
1553 Launch Pad tab. This can help diagnose deployment failures
1554 caused by wiring which comes loose under high acceleration.
1558 <title>Descent</title>
1560 Once the rocket has reached apogee and (we hope) activated the
1561 apogee charge, attention switches to tracking the rocket on
1562 the way back to the ground, and for dual-deploy flights,
1563 waiting for the main charge to fire.
1566 To monitor whether the apogee charge operated correctly, the
1567 current descent rate is reported along with the current
1568 height. Good descent rates vary based on the choice of recovery
1569 components, but generally range from 15-30m/s on drogue and should
1570 be below 10m/s when under the main parachute in a dual-deploy flight.
1573 With GPS-equipped flight computers, you can locate the rocket in the
1574 sky using the elevation and bearing information to figure
1575 out where to look. Elevation is in degrees above the
1576 horizon. Bearing is reported in degrees relative to true
1577 north. Range can help figure out how big the rocket will
1578 appear. Ground Distance shows how far it is to a point
1579 directly under the rocket and can help figure out where the
1580 rocket is likely to land. Note that all of these values are
1581 relative to the pad location. If the elevation is near 90°,
1582 the rocket is over the pad, not over you.
1585 Finally, the igniter voltages are reported in this tab as
1586 well, both to monitor the main charge as well as to see what
1587 the status of the apogee charge is. Note that some commercial
1588 e-matches are designed to retain continuity even after being
1589 fired, and will continue to show as green or return from red to
1594 <title>Landed</title>
1596 Once the rocket is on the ground, attention switches to
1597 recovery. While the radio signal is often lost once the
1598 rocket is on the ground, the last reported GPS position is
1599 generally within a short distance of the actual landing location.
1602 The last reported GPS position is reported both by
1603 latitude and longitude as well as a bearing and distance from
1604 the launch pad. The distance should give you a good idea of
1605 whether to walk or hitch a ride. Take the reported
1606 latitude and longitude and enter them into your hand-held GPS
1607 unit and have that compute a track to the landing location.
1610 Our flight computers will continue to transmit RDF
1611 tones after landing, allowing you to locate the rocket by
1612 following the radio signal if necessary. You may need to get
1613 away from the clutter of the flight line, or even get up on
1614 a hill (or your neighbor's RV roof) to receive the RDF signal.
1617 The maximum height, speed and acceleration reported
1618 during the flight are displayed for your admiring observers.
1619 The accuracy of these immediate values depends on the quality
1620 of your radio link and how many packets were received.
1621 Recovering the on-board data after flight may yield
1622 more precise results.
1625 To get more detailed information about the flight, you can
1626 click on the 'Graph Flight' button which will bring up a
1627 graph window for the current flight.
1631 <title>Site Map</title>
1633 When the TeleMetrum has a GPS fix, the Site Map tab will map
1634 the rocket's position to make it easier for you to locate the
1635 rocket, both while it is in the air, and when it has landed. The
1636 rocket's state is indicated by color: white for pad, red for
1637 boost, pink for fast, yellow for coast, light blue for drogue,
1638 dark blue for main, and black for landed.
1641 The map's scale is approximately 3m (10ft) per pixel. The map
1642 can be dragged using the left mouse button. The map will attempt
1643 to keep the rocket roughly centered while data is being received.
1646 Images are fetched automatically via the Google Maps Static API,
1647 and cached on disk for reuse. If map images cannot be downloaded,
1648 the rocket's path will be traced on a dark gray background
1652 You can pre-load images for your favorite launch sites
1653 before you leave home; check out the 'Preload Maps' section below.
1658 <title>Save Flight Data</title>
1660 The altimeter records flight data to its internal flash memory.
1661 TeleMetrum data is recorded at a much higher rate than the telemetry
1662 system can handle, and is not subject to radio drop-outs. As
1663 such, it provides a more complete and precise record of the
1664 flight. The 'Save Flight Data' button allows you to read the
1665 flash memory and write it to disk.
1668 Clicking on the 'Save Flight Data' button brings up a list of
1669 connected flight computers and TeleDongle devices. If you select a
1670 flight computer, the flight data will be downloaded from that
1671 device directly. If you select a TeleDongle device, flight data
1672 will be downloaded from a flight computer over radio link via the
1673 specified TeleDongle. See the chapter on Controlling An Altimeter
1674 Over The Radio Link for more information.
1677 After the device has been selected, a dialog showing the
1678 flight data saved in the device will be shown allowing you to
1679 select which flights to download and which to delete. With
1680 version 0.9 or newer firmware, you must erase flights in order
1681 for the space they consume to be reused by another
1682 flight. This prevents accidentally losing flight data
1683 if you neglect to download data before flying again. Note that
1684 if there is no more space available in the device, then no
1685 data will be recorded during the next flight.
1688 The file name for each flight log is computed automatically
1689 from the recorded flight date, altimeter serial number and
1690 flight number information.
1694 <title>Replay Flight</title>
1696 Select this button and you are prompted to select a flight
1697 record file, either a .telem file recording telemetry data or a
1698 .eeprom file containing flight data saved from the altimeter
1702 Once a flight record is selected, the flight monitor interface
1703 is displayed and the flight is re-enacted in real time. Check
1704 the Monitor Flight chapter above to learn how this window operates.
1708 <title>Graph Data</title>
1710 Select this button and you are prompted to select a flight
1711 record file, either a .telem file recording telemetry data or a
1712 .eeprom file containing flight data saved from
1716 Once a flight record is selected, a window with multiple tabs is
1720 <term>Flight Graph</term>
1723 By default, the graph contains acceleration (blue),
1724 velocity (green) and altitude (red).
1729 <term>Configure Graph</term>
1732 This selects which graph elements to show, and, at the
1733 very bottom, lets you switch between metric and
1739 <term>Flight Statistics</term>
1742 Shows overall data computed from the flight.
1750 Shows a satellite image of the flight area overlaid
1751 with the path of the flight. The red concentric
1752 circles mark the launch pad, the black concentric
1753 circles mark the landing location.
1760 The graph can be zoomed into a particular area by clicking and
1761 dragging down and to the right. Once zoomed, the graph can be
1762 reset by clicking and dragging up and to the left. Holding down
1763 control and clicking and dragging allows the graph to be panned.
1764 The right mouse button causes a pop-up menu to be displayed, giving
1765 you the option save or print the plot.
1768 Note that telemetry files will generally produce poor graphs
1769 due to the lower sampling rate and missed telemetry packets.
1770 Use saved flight data in .eeprom files for graphing where possible.
1774 <title>Export Data</title>
1776 This tool takes the raw data files and makes them available for
1777 external analysis. When you select this button, you are prompted to
1778 select a flight data file, which can be either a .eeprom or .telem.
1779 The .eeprom files contain higher resolution and more continuous data,
1780 while .telem files contain receiver signal strength information.
1781 Next, a second dialog appears which is used to select
1782 where to write the resulting file. It has a selector to choose
1783 between CSV and KML file formats.
1786 <title>Comma Separated Value Format</title>
1788 This is a text file containing the data in a form suitable for
1789 import into a spreadsheet or other external data analysis
1790 tool. The first few lines of the file contain the version and
1791 configuration information from the altimeter, then
1792 there is a single header line which labels all of the
1793 fields. All of these lines start with a '#' character which
1794 many tools can be configured to skip over.
1797 The remaining lines of the file contain the data, with each
1798 field separated by a comma and at least one space. All of
1799 the sensor values are converted to standard units, with the
1800 barometric data reported in both pressure, altitude and
1801 height above pad units.
1805 <title>Keyhole Markup Language (for Google Earth)</title>
1807 This is the format used by Google Earth to provide an overlay
1808 within that application. With this, you can use Google Earth to
1809 see the whole flight path in 3D.
1814 <title>Configure Altimeter</title>
1816 Select this button and then select either an altimeter or
1817 TeleDongle Device from the list provided. Selecting a TeleDongle
1818 device will use the radio link to configure a remote altimeter.
1821 The first few lines of the dialog provide information about the
1822 connected device, including the product name,
1823 software version and hardware serial number. Below that are the
1824 individual configuration entries.
1827 At the bottom of the dialog, there are four buttons:
1834 This writes any changes to the
1835 configuration parameter block in flash memory. If you don't
1836 press this button, any changes you make will be lost.
1844 This resets the dialog to the most recently saved values,
1845 erasing any changes you have made.
1853 This reboots the device. Use this to
1854 switch from idle to pad mode by rebooting once the rocket is
1855 oriented for flight, or to confirm changes you think you saved
1864 This closes the dialog. Any unsaved changes will be
1871 The rest of the dialog contains the parameters to be configured.
1874 <title>Main Deploy Altitude</title>
1876 This sets the altitude (above the recorded pad altitude) at
1877 which the 'main' igniter will fire. The drop-down menu shows
1878 some common values, but you can edit the text directly and
1879 choose whatever you like. If the apogee charge fires below
1880 this altitude, then the main charge will fire two seconds
1881 after the apogee charge fires.
1885 <title>Apogee Delay</title>
1887 When flying redundant electronics, it's often important to
1888 ensure that multiple apogee charges don't fire at precisely
1889 the same time, as that can over pressurize the apogee deployment
1890 bay and cause a structural failure of the air-frame. The Apogee
1891 Delay parameter tells the flight computer to fire the apogee
1892 charge a certain number of seconds after apogee has been
1897 <title>Radio Frequency</title>
1899 This configures which of the frequencies to use for both
1900 telemetry and packet command mode. Note that if you set this
1901 value via packet command mode, the TeleDongle frequency will
1902 also be automatically reconfigured to match so that
1903 communication will continue afterwards.
1907 <title>RF Calibration</title>
1909 The radios in every Altus Metrum device are calibrated at the
1910 factory to ensure that they transmit and receive on the
1911 specified frequency. If you need to you can adjust the calibration
1912 by changing this value. Do not do this without understanding what
1913 the value means, read the appendix on calibration and/or the source
1914 code for more information. To change a TeleDongle's calibration,
1915 you must reprogram the unit completely.
1919 <title>Telemetry/RDF/APRS Enable</title>
1921 Enables the radio for transmission during flight. When
1922 disabled, the radio will not transmit anything during flight
1927 <title>APRS Interval</title>
1929 How often to transmit GPS information via APRS. This option
1930 is available on TeleMetrum v2 and TeleMega
1931 boards. TeleMetrum v1 boards cannot transmit APRS
1932 packets. Note that a single APRS packet takes nearly a full
1933 second to transmit, so enabling this option will prevent
1934 sending any other telemetry during that time.
1938 <title>Callsign</title>
1940 This sets the call sign included in each telemetry packet. Set this
1941 as needed to conform to your local radio regulations.
1945 <title>Maximum Flight Log Size</title>
1947 This sets the space (in kilobytes) allocated for each flight
1948 log. The available space will be divided into chunks of this
1949 size. A smaller value will allow more flights to be stored,
1950 a larger value will record data from longer flights.
1954 <title>Ignite Mode</title>
1956 TeleMetrum and TeleMini provide two igniter channels as they
1957 were originally designed as dual-deploy flight
1958 computers. This configuration parameter allows the two
1959 channels to be used in different configurations.
1963 <term>Dual Deploy</term>
1966 This is the usual mode of operation; the
1967 'apogee' channel is fired at apogee and the 'main'
1968 channel at the height above ground specified by the
1969 'Main Deploy Altitude' during descent.
1974 <term>Redundant Apogee</term>
1977 This fires both channels at
1978 apogee, the 'apogee' channel first followed after a two second
1979 delay by the 'main' channel.
1984 <term>Redundant Main</term>
1987 This fires both channels at the
1988 height above ground specified by the Main Deploy
1989 Altitude setting during descent. The 'apogee'
1990 channel is fired first, followed after a two second
1991 delay by the 'main' channel.
1998 <title>Pad Orientation</title>
2000 Because they include accelerometers, TeleMetrum and
2001 TeleMega are sensitive to the orientation of the board. By
2002 default, they expect the antenna end to point forward. This
2003 parameter allows that default to be changed, permitting the
2004 board to be mounted with the antenna pointing aft instead.
2008 <term>Antenna Up</term>
2011 In this mode, the antenna end of the
2012 flight computer must point forward, in line with the
2013 expected flight path.
2018 <term>Antenna Down</term>
2021 In this mode, the antenna end of the
2022 flight computer must point aft, in line with the
2023 expected flight path.
2030 <title>Configure Pyro Channels</title>
2032 This opens a separate window to configure the additional
2033 pyro channels available on TeleMega. One column is
2034 presented for each channel. Each row represents a single
2035 parameter, if enabled the parameter must meet the specified
2036 test for the pyro channel to be fired. See the Pyro Channels
2037 section in the System Operation chapter above for a
2038 description of these parameters.
2041 Select conditions and set the related value; the pyro
2042 channel will be activated when <emphasis>all</emphasis> of the
2043 conditions are met. Each pyro channel has a separate set of
2044 configuration values, so you can use different values for
2045 the same condition with different channels.
2048 Once you have selected the appropriate configuration for all
2049 of the necessary pyro channels, you can save the pyro
2050 configuration along with the rest of the flight computer
2051 configuration by pressing the 'Save' button in the main
2052 Configure Flight Computer window.
2057 <title>Configure AltosUI</title>
2059 This button presents a dialog so that you can configure the AltosUI global settings.
2062 <title>Voice Settings</title>
2064 AltosUI provides voice announcements during flight so that you
2065 can keep your eyes on the sky and still get information about
2066 the current flight status. However, sometimes you don't want
2071 <para>Enable—turns all voice announcements on and off</para>
2075 Test Voice—Plays a short message allowing you to verify
2076 that the audio system is working and the volume settings
2083 <title>Log Directory</title>
2085 AltosUI logs all telemetry data and saves all TeleMetrum flash
2086 data to this directory. This directory is also used as the
2087 staring point when selecting data files for display or export.
2090 Click on the directory name to bring up a directory choosing
2091 dialog, select a new directory and click 'Select Directory' to
2092 change where AltosUI reads and writes data files.
2096 <title>Callsign</title>
2098 This value is transmitted in each command packet sent from
2099 TeleDongle and received from an altimeter. It is not used in
2100 telemetry mode, as the callsign configured in the altimeter board
2101 is included in all telemetry packets. Configure this
2102 with the AltosUI operators call sign as needed to comply with
2103 your local radio regulations.
2106 Note that to successfully command a flight computer over the radio
2107 (to configure the altimeter, monitor idle, or fire pyro charges),
2108 the callsign configured here must exactly match the callsign
2109 configured in the flight computer. This matching is case
2114 <title>Imperial Units</title>
2116 This switches between metric units (meters) and imperial
2117 units (feet and miles). This affects the display of values
2118 use during flight monitoring, configuration, data graphing
2119 and all of the voice announcements. It does not change the
2120 units used when exporting to CSV files, those are always
2121 produced in metric units.
2125 <title>Font Size</title>
2127 Selects the set of fonts used in the flight monitor
2128 window. Choose between the small, medium and large sets.
2132 <title>Serial Debug</title>
2134 This causes all communication with a connected device to be
2135 dumped to the console from which AltosUI was started. If
2136 you've started it from an icon or menu entry, the output
2137 will simply be discarded. This mode can be useful to debug
2138 various serial communication issues.
2142 <title>Manage Frequencies</title>
2144 This brings up a dialog where you can configure the set of
2145 frequencies shown in the various frequency menus. You can
2146 add as many as you like, or even reconfigure the default
2147 set. Changing this list does not affect the frequency
2148 settings of any devices, it only changes the set of
2149 frequencies shown in the menus.
2154 <title>Configure Groundstation</title>
2156 Select this button and then select a TeleDongle Device from the list provided.
2159 The first few lines of the dialog provide information about the
2160 connected device, including the product name,
2161 software version and hardware serial number. Below that are the
2162 individual configuration entries.
2165 Note that the TeleDongle itself doesn't save any configuration
2166 data, the settings here are recorded on the local machine in
2167 the Java preferences database. Moving the TeleDongle to
2168 another machine, or using a different user account on the same
2169 machine will cause settings made here to have no effect.
2172 At the bottom of the dialog, there are three buttons:
2179 This writes any changes to the
2180 local Java preferences file. If you don't
2181 press this button, any changes you make will be lost.
2189 This resets the dialog to the most recently saved values,
2190 erasing any changes you have made.
2198 This closes the dialog. Any unsaved changes will be
2205 The rest of the dialog contains the parameters to be configured.
2208 <title>Frequency</title>
2210 This configures the frequency to use for both telemetry and
2211 packet command mode. Set this before starting any operation
2212 involving packet command mode so that it will use the right
2213 frequency. Telemetry monitoring mode also provides a menu to
2214 change the frequency, and that menu also sets the same Java
2215 preference value used here.
2219 <title>Radio Calibration</title>
2221 The radios in every Altus Metrum device are calibrated at the
2222 factory to ensure that they transmit and receive on the
2223 specified frequency. To change a TeleDongle's calibration,
2224 you must reprogram the unit completely, so this entry simply
2225 shows the current value and doesn't allow any changes.
2230 <title>Flash Image</title>
2232 This reprograms Altus Metrum devices with new
2233 firmware. TeleMetrum v1.x, TeleDongle, TeleMini and TeleBT are
2234 all reprogrammed by using another similar unit as a
2235 programming dongle (pair programming). TeleMega, TeleMetrum v2
2236 and EasyMini are all programmed directly over their USB ports
2237 (self programming). Please read the directions for flashing
2238 devices in the Updating Device Firmware chapter below.
2241 For “self programming”, connect USB to the device to be
2242 programmed and push the 'Flash Image' button. That will
2243 present a dialog box listing all of the connected
2244 devices. Carefully select the device to be programmed.
2247 For “pair programming”, once you have the programmer and
2248 target devices connected, push the 'Flash Image' button. That
2249 will present a dialog box listing all of the connected
2250 devices. Carefully select the programmer device, not the
2251 device to be programmed.
2254 Next, select the image to flash to the device. These are named
2255 with the product name and firmware version. The file selector
2256 will start in the directory containing the firmware included
2257 with the AltosUI package. Navigate to the directory containing
2258 the desired firmware if it isn't there.
2261 Next, a small dialog containing the device serial number and
2262 RF calibration values should appear. If these values are
2263 incorrect (possibly due to a corrupted image in the device),
2264 enter the correct values here.
2267 Finally, a dialog containing a progress bar will follow the
2268 programming process.
2271 When programming is complete, the target device will
2272 reboot. Note that if a pair programmed target device is
2273 connected via USB, you will have to unplug it and then plug it
2274 back in for the USB connection to reset so that you can
2275 communicate with the device again.
2279 <title>Fire Igniter</title>
2281 This activates the igniter circuits in the flight computer to help
2282 test recovery systems deployment. Because this command can operate
2283 over the Packet Command Link, you can prepare the rocket as
2284 for flight and then test the recovery system without needing
2285 to snake wires inside the air-frame.
2288 Selecting the 'Fire Igniter' button brings up the usual device
2289 selection dialog. Pick the desired device. This brings up another
2290 window which shows the current continuity test status for both
2291 apogee and main charges.
2294 Next, select the desired igniter to fire. This will enable the
2298 Select the 'Arm' button. This enables the 'Fire' button. The
2299 word 'Arm' is replaced by a countdown timer indicating that
2300 you have 10 seconds to press the 'Fire' button or the system
2301 will deactivate, at which point you start over again at
2302 selecting the desired igniter.
2306 <title>Scan Channels</title>
2308 This listens for telemetry packets on all of the configured
2309 frequencies, displaying information about each device it
2310 receives a packet from. You can select which of the three
2311 telemetry formats should be tried; by default, it only listens
2312 for the standard telemetry packets used in v1.0 and later
2317 <title>Load Maps</title>
2319 Before heading out to a new launch site, you can use this to
2320 load satellite images in case you don't have internet
2321 connectivity at the site. This loads a fairly large area
2322 around the launch site, which should cover any flight you're likely to make.
2325 There's a drop-down menu of launch sites we know about; if
2326 your favorites aren't there, please let us know the lat/lon
2327 and name of the site. The contents of this list are actually
2328 downloaded from our server at run-time, so as new sites are sent
2329 in, they'll get automatically added to this list.
2332 If the launch site isn't in the list, you can manually enter the lat/lon values
2335 Clicking the 'Load Map' button will fetch images from Google
2336 Maps; note that Google limits how many images you can fetch at
2337 once, so if you load more than one launch site, you may get
2338 some gray areas in the map which indicate that Google is tired
2339 of sending data to you. Try again later.
2343 <title>Monitor Idle</title>
2345 This brings up a dialog similar to the Monitor Flight UI,
2346 except it works with the altimeter in “idle” mode by sending
2347 query commands to discover the current state rather than
2348 listening for telemetry packets. Because this uses command
2349 mode, it needs to have the TeleDongle and flight computer
2350 callsigns match exactly. If you can receive telemetry, but
2351 cannot manage to run Monitor Idle, then it's very likely that
2352 your callsigns are different in some way.
2357 <title>AltosDroid</title>
2359 AltosDroid provides the same flight monitoring capabilities as
2360 AltosUI, but runs on Android devices and is designed to connect
2361 to a TeleBT receiver over Bluetooth™. AltosDroid monitors
2362 telemetry data, logging it to internal storage in the Android
2363 device, and presents that data in a UI the same way the 'Monitor
2364 Flight' window does in AltosUI.
2367 This manual will explain how to configure AltosDroid, connect
2368 to TeleBT, operate the flight monitoring interface and describe
2369 what the displayed data means.
2372 <title>Installing AltosDroid</title>
2374 AltosDroid is available from the Google Play store. To install
2375 it on your Android device, open the Google Play Store
2376 application and search for “altosdroid”. Make sure you don't
2377 have a space between “altos” and “droid” or you probably won't
2378 find what you want. That should bring you to the right page
2379 from which you can download and install the application.
2383 <title>Connecting to TeleBT</title>
2385 Press the Android 'Menu' button or soft-key to see the
2386 configuration options available. Select the 'Connect a device'
2387 option and then the 'Scan for devices' entry at the bottom to
2388 look for your TeleBT device. Select your device, and when it
2389 asks for the code, enter '1234'.
2392 Subsequent connections will not require you to enter that
2393 code, and your 'paired' device will appear in the list without
2398 <title>Configuring AltosDroid</title>
2400 The only configuration option available for AltosDroid is
2401 which frequency to listen on. Press the Android 'Menu' button
2402 or soft-key and pick the 'Select radio frequency' entry. That
2403 brings up a menu of pre-set radio frequencies; pick the one
2404 which matches your altimeter.
2408 <title>AltosDroid Flight Monitoring</title>
2410 AltosDroid is designed to mimic the AltosUI flight monitoring
2411 display, providing separate tabs for each stage of your rocket
2412 flight along with a tab containing a map of the local area
2413 with icons marking the current location of the altimeter and
2419 The 'Launch Pad' tab shows information used to decide when the
2420 rocket is ready for flight. The first elements include red/green
2421 indicators, if any of these is red, you'll want to evaluate
2422 whether the rocket is ready to launch:
2425 <term>Battery Voltage</term>
2428 This indicates whether the Li-Po battery
2429 powering the TeleMetrum has sufficient charge to last for
2430 the duration of the flight. A value of more than
2431 3.8V is required for a 'GO' status.
2436 <term>Apogee Igniter Voltage</term>
2439 This indicates whether the apogee
2440 igniter has continuity. If the igniter has a low
2441 resistance, then the voltage measured here will be close
2442 to the Li-Po battery voltage. A value greater than 3.2V is
2443 required for a 'GO' status.
2448 <term>Main Igniter Voltage</term>
2451 This indicates whether the main
2452 igniter has continuity. If the igniter has a low
2453 resistance, then the voltage measured here will be close
2454 to the Li-Po battery voltage. A value greater than 3.2V is
2455 required for a 'GO' status.
2460 <term>On-board Data Logging</term>
2463 This indicates whether there is
2464 space remaining on-board to store flight data for the
2465 upcoming flight. If you've downloaded data, but failed
2466 to erase flights, there may not be any space
2467 left. TeleMetrum can store multiple flights, depending
2468 on the configured maximum flight log size. TeleMini
2469 stores only a single flight, so it will need to be
2470 downloaded and erased after each flight to capture
2471 data. This only affects on-board flight logging; the
2472 altimeter will still transmit telemetry and fire
2473 ejection charges at the proper times.
2478 <term>GPS Locked</term>
2481 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
2482 currently able to compute position information. GPS requires
2483 at least 4 satellites to compute an accurate position.
2488 <term>GPS Ready</term>
2491 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
2492 10 consecutive positions without losing lock. This ensures
2493 that the GPS receiver has reliable reception from the
2501 The Launchpad tab also shows the computed launch pad position
2502 and altitude, averaging many reported positions to improve the
2503 accuracy of the fix.
2508 <title>Downloading Flight Logs</title>
2510 AltosDroid always saves every bit of telemetry data it
2511 receives. To download that to a computer for use with AltosUI,
2512 simply remove the SD card from your Android device, or connect
2513 your device to your computer's USB port and browse the files
2514 on that device. You will find '.telem' files in the TeleMetrum
2515 directory that will work with AltosUI directly.
2520 <title>Using Altus Metrum Products</title>
2522 <title>Being Legal</title>
2524 First off, in the US, you need an <ulink url="http://www.altusmetrum.org/Radio/">amateur radio license</ulink> or
2525 other authorization to legally operate the radio transmitters that are part
2530 <title>In the Rocket</title>
2532 In the rocket itself, you just need a flight computer and
2533 a single-cell, 3.7 volt nominal Li-Po rechargeable battery. An
2534 850mAh battery weighs less than a 9V alkaline battery, and will
2535 run a TeleMetrum or TeleMega for hours.
2536 A 110mAh battery weighs less than a triple A battery and is a good
2537 choice for use with TeleMini.
2540 By default, we ship flight computers with a simple wire antenna.
2541 If your electronics bay or the air-frame it resides within is made
2542 of carbon fiber, which is opaque to RF signals, you may prefer to
2543 install an SMA connector so that you can run a coaxial cable to an
2544 antenna mounted elsewhere in the rocket. However, note that the
2545 GPS antenna is fixed on all current products, so you really want
2546 to install the flight computer in a bay made of RF-transparent
2547 materials if at all possible.
2551 <title>On the Ground</title>
2553 To receive the data stream from the rocket, you need an antenna and short
2554 feed-line connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. If possible, use an SMA to BNC
2555 adapter instead of feedline between the antenna feedpoint and
2556 TeleDongle, as this will give you the best performance. The
2557 TeleDongle in turn plugs directly into the USB port on a notebook
2558 computer. Because TeleDongle looks like a simple serial port, your computer
2559 does not require special device drivers... just plug it in.
2562 The GUI tool, AltosUI, is written in Java and runs across
2563 Linux, Mac OS and Windows. There's also a suite of C tools
2564 for Linux which can perform most of the same tasks.
2567 Alternatively, a TeleBT attached with an SMA to BNC adapter at the
2568 feed point of a hand-held yagi used in conjunction with an Android
2569 device running AltosDroid makes an outstanding ground station.
2572 After the flight, you can use the radio link to extract the more detailed data
2573 logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
2574 TeleMetrum board directly. Pulling out the data without having to open up
2575 the rocket is pretty cool! A USB cable is also how you charge the Li-Po
2576 battery, so you'll want one of those anyway... the same cable used by lots
2577 of digital cameras and other modern electronic stuff will work fine.
2580 If your rocket lands out of sight, you may enjoy having a hand-held
2581 GPS receiver, so that you can put in a way-point for the last
2582 reported rocket position before touch-down. This makes looking for
2583 your rocket a lot like Geo-Caching... just go to the way-point and
2584 look around starting from there. AltosDroid on an Android device
2585 with GPS receiver works great for this, too!
2588 You may also enjoy having a ham radio “HT” that covers the 70cm band... you
2589 can use that with your antenna to direction-find the rocket on the ground
2590 the same way you can use a Walston or Beeline tracker. This can be handy
2591 if the rocket is hiding in sage brush or a tree, or if the last GPS position
2592 doesn't get you close enough because the rocket dropped into a canyon, or
2593 the wind is blowing it across a dry lake bed, or something like that... Keith
2594 currently uses a Yaesu VX-7R, Bdale has a Baofung UV-5R
2595 which isn't as nice, but was a whole lot cheaper.
2598 So, to recap, on the ground the hardware you'll need includes:
2599 <orderedlist inheritnum='inherit' numeration='arabic'>
2602 an antenna and feed-line or adapter
2617 optionally, a hand-held GPS receiver
2622 optionally, an HT or receiver covering 435 MHz
2628 The best hand-held commercial directional antennas we've found for radio
2629 direction finding rockets are from
2630 <ulink url="http://www.arrowantennas.com/" >
2633 The 440-3 and 440-5 are both good choices for finding a
2634 TeleMetrum- or TeleMini- equipped rocket when used with a suitable
2635 70cm HT. TeleDongle and an SMA to BNC adapter fit perfectly
2636 between the driven element and reflector of Arrow antennas.
2640 <title>Data Analysis</title>
2642 Our software makes it easy to log the data from each flight, both the
2643 telemetry received during the flight itself, and the more
2644 complete data log recorded in the flash memory on the altimeter
2645 board. Once this data is on your computer, our post-flight tools make it
2646 easy to quickly get to the numbers everyone wants, like apogee altitude,
2647 max acceleration, and max velocity. You can also generate and view a
2648 standard set of plots showing the altitude, acceleration, and
2649 velocity of the rocket during flight. And you can even export a TeleMetrum data file
2650 usable with Google Maps and Google Earth for visualizing the flight path
2651 in two or three dimensions!
2654 Our ultimate goal is to emit a set of files for each flight that can be
2655 published as a web page per flight, or just viewed on your local disk with
2660 <title>Future Plans</title>
2662 We've designed a simple GPS based radio tracker called TeleGPS.
2663 If all goes well, we hope to introduce this in the first
2667 We have designed and prototyped several “companion boards” that
2668 can attach to the companion connector on TeleMetrum and TeleMega
2669 flight computers to collect more data, provide more pyro channels,
2670 and so forth. We do not yet know if or when any of these boards
2671 will be produced in enough quantity to sell. If you have specific
2672 interests for data collection or control of events in your rockets
2673 beyond the capabilities of our existing productions, please let
2677 Because all of our work is open, both the hardware designs and the
2678 software, if you have some great idea for an addition to the current
2679 Altus Metrum family, feel free to dive in and help! Or let us know
2680 what you'd like to see that we aren't already working on, and maybe
2681 we'll get excited about it too...
2685 <ulink url="http://altusmetrum.org/">web site</ulink> for more news
2686 and information as our family of products evolves!
2691 <title>Altimeter Installation Recommendations</title>
2693 Building high-power rockets that fly safely is hard enough. Mix
2694 in some sophisticated electronics and a bunch of radio energy
2695 and some creativity and/or compromise may be required. This chapter
2696 contains some suggestions about how to install Altus Metrum
2697 products into a rocket air-frame, including how to safely and
2698 reliably mix a variety of electronics into the same air-frame.
2701 <title>Mounting the Altimeter</title>
2703 The first consideration is to ensure that the altimeter is
2704 securely fastened to the air-frame. For most of our products, we
2705 prefer nylon standoffs and nylon screws; they're good to at least 50G
2706 and cannot cause any electrical issues on the board. Metal screws
2707 and standoffs are fine, too, just be careful to avoid electrical
2708 shorts! For TeleMini v1.0, we usually cut small pieces of 1/16 inch
2710 under the screw holes, and then take 2x56 nylon screws and
2711 screw them through the TeleMini mounting holes, through the
2712 balsa and into the underlying material.
2714 <orderedlist inheritnum='inherit' numeration='arabic'>
2717 Make sure accelerometer-equipped products like TeleMetrum and
2718 TeleMega are aligned precisely along the axis of
2719 acceleration so that the accelerometer can accurately
2720 capture data during the flight.
2725 Watch for any metal touching components on the
2726 board. Shorting out connections on the bottom of the board
2727 can cause the altimeter to fail during flight.
2733 <title>Dealing with the Antenna</title>
2735 The antenna supplied is just a piece of solid, insulated,
2736 wire. If it gets damaged or broken, it can be easily
2737 replaced. It should be kept straight and not cut; bending or
2738 cutting it will change the resonant frequency and/or
2739 impedance, making it a less efficient radiator and thus
2740 reducing the range of the telemetry signal.
2743 Keeping metal away from the antenna will provide better range
2744 and a more even radiation pattern. In most rockets, it's not
2745 entirely possible to isolate the antenna from metal
2746 components; there are often bolts, all-thread and wires from other
2747 electronics to contend with. Just be aware that the more stuff
2748 like this around the antenna, the lower the range.
2751 Make sure the antenna is not inside a tube made or covered
2752 with conducting material. Carbon fiber is the most common
2753 culprit here -- CF is a good conductor and will effectively
2754 shield the antenna, dramatically reducing signal strength and
2755 range. Metallic flake paint is another effective shielding
2756 material which should be avoided around any antennas.
2759 If the ebay is large enough, it can be convenient to simply
2760 mount the altimeter at one end and stretch the antenna out
2761 inside. Taping the antenna to the sled can keep it straight
2762 under acceleration. If there are metal rods, keep the
2763 antenna as far away as possible.
2766 For a shorter ebay, it's quite practical to have the antenna
2767 run through a bulkhead and into an adjacent bay. Drill a small
2768 hole in the bulkhead, pass the antenna wire through it and
2769 then seal it up with glue or clay. We've also used acrylic
2770 tubing to create a cavity for the antenna wire. This works a
2771 bit better in that the antenna is known to stay straight and
2772 not get folded by recovery components in the bay. Angle the
2773 tubing towards the side wall of the rocket and it ends up
2774 consuming very little space.
2777 If you need to place the UHF antenna at a distance from the
2778 altimeter, you can replace the antenna with an edge-mounted
2779 SMA connector, and then run 50Ω coax from the board to the
2780 antenna. Building a remote antenna is beyond the scope of this
2785 <title>Preserving GPS Reception</title>
2787 The GPS antenna and receiver used in TeleMetrum and TeleMega is
2788 highly sensitive and normally have no trouble tracking enough
2789 satellites to provide accurate position information for
2790 recovering the rocket. However, there are many ways the GPS signal
2791 can end up attenuated, negatively affecting GPS performance.
2792 <orderedlist inheritnum='inherit' numeration='arabic'>
2795 Conductive tubing or coatings. Carbon fiber and metal
2796 tubing, or metallic paint will all dramatically attenuate the
2797 GPS signal. We've never heard of anyone successfully
2798 receiving GPS from inside these materials.
2803 Metal components near the GPS patch antenna. These will
2804 de-tune the patch antenna, changing the resonant frequency
2805 away from the L1 carrier and reduce the effectiveness of the
2806 antenna. You can place as much stuff as you like beneath the
2807 antenna as that's covered with a ground plane. But, keep
2808 wires and metal out from above the patch antenna.
2815 <title>Radio Frequency Interference</title>
2817 Any altimeter will generate RFI; the digital circuits use
2818 high-frequency clocks that spray radio interference across a
2819 wide band. Altus Metrum altimeters generate intentional radio
2820 signals as well, increasing the amount of RF energy around the board.
2823 Rocketry altimeters also use precise sensors measuring air
2824 pressure and acceleration. Tiny changes in voltage can cause
2825 these sensor readings to vary by a huge amount. When the
2826 sensors start mis-reporting data, the altimeter can either
2827 fire the igniters at the wrong time, or not fire them at all.
2830 Voltages are induced when radio frequency energy is
2831 transmitted from one circuit to another. Here are things that
2832 influence the induced voltage and current:
2837 Keep wires from different circuits apart. Moving circuits
2838 further apart will reduce RFI.
2843 Avoid parallel wires from different circuits. The longer two
2844 wires run parallel to one another, the larger the amount of
2845 transferred energy. Cross wires at right angles to reduce
2851 Twist wires from the same circuits. Two wires the same
2852 distance from the transmitter will get the same amount of
2853 induced energy which will then cancel out. Any time you have
2854 a wire pair running together, twist the pair together to
2855 even out distances and reduce RFI. For altimeters, this
2856 includes battery leads, switch hookups and igniter
2862 Avoid resonant lengths. Know what frequencies are present
2863 in the environment and avoid having wire lengths near a
2864 natural resonant length. Altus Metrum products transmit on the
2865 70cm amateur band, so you should avoid lengths that are a
2866 simple ratio of that length; essentially any multiple of ¼
2867 of the wavelength (17.5cm).
2873 <title>The Barometric Sensor</title>
2875 Altusmetrum altimeters measure altitude with a barometric
2876 sensor, essentially measuring the amount of air above the
2877 rocket to figure out how high it is. A large number of
2878 measurements are taken as the altimeter initializes itself to
2879 figure out the pad altitude. Subsequent measurements are then
2880 used to compute the height above the pad.
2883 To accurately measure atmospheric pressure, the ebay
2884 containing the altimeter must be vented outside the
2885 air-frame. The vent must be placed in a region of linear
2886 airflow, have smooth edges, and away from areas of increasing or
2887 decreasing pressure.
2890 All barometric sensors are quite sensitive to chemical damage from
2891 the products of APCP or BP combustion, so make sure the ebay is
2892 carefully sealed from any compartment which contains ejection
2897 <title>Ground Testing</title>
2899 The most important aspect of any installation is careful
2900 ground testing. Bringing an air-frame up to the LCO table which
2901 hasn't been ground tested can lead to delays or ejection
2902 charges firing on the pad, or, even worse, a recovery system
2906 Do a 'full systems' test that includes wiring up all igniters
2907 without any BP and turning on all of the electronics in flight
2908 mode. This will catch any mistakes in wiring and any residual
2909 RFI issues that might accidentally fire igniters at the wrong
2910 time. Let the air-frame sit for several minutes, checking for
2911 adequate telemetry signal strength and GPS lock. If any igniters
2912 fire unexpectedly, find and resolve the issue before loading any
2916 Ground test the ejection charges. Prepare the rocket for
2917 flight, loading ejection charges and igniters. Completely
2918 assemble the air-frame and then use the 'Fire Igniters'
2919 interface through a TeleDongle to command each charge to
2920 fire. Make sure the charge is sufficient to robustly separate
2921 the air-frame and deploy the recovery system.
2926 <title>Updating Device Firmware</title>
2928 TeleMega, TeleMetrum v2 and EasyMini are all programmed directly
2929 over their USB connectors (self programming). TeleMetrum v1, TeleMini and
2930 TeleDongle are all programmed by using another device as a
2931 programmer (pair programming). It's important to recognize which
2932 kind of devices you have before trying to reprogram them.
2935 You may wish to begin by ensuring you have current firmware images.
2936 These are distributed as part of the AltOS software bundle that
2937 also includes the AltosUI ground station program. Newer ground
2938 station versions typically work fine with older firmware versions,
2939 so you don't need to update your devices just to try out new
2940 software features. You can always download the most recent
2941 version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
2944 If you need to update the firmware on a TeleDongle, we recommend
2945 updating the altimeter first, before updating TeleDongle. However,
2946 note that TeleDongle rarely need to be updated. Any firmware version
2947 1.0.1 or later will work, version 1.2.1 may have improved receiver
2948 performance slightly.
2951 Self-programmable devices (TeleMega, TeleMetrum v2 and EasyMini)
2952 are reprogrammed by connecting them to your computer over USB
2956 Updating TeleMega, TeleMetrum v2 or EasyMini Firmware
2958 <orderedlist inheritnum='inherit' numeration='arabic'>
2961 Attach a battery and power switch to the target
2962 device. Power up the device.
2967 Using a Micro USB cable, connect the target device to your
2968 computer's USB socket.
2973 Run AltosUI, and select 'Flash Image' from the File menu.
2978 Select the target device in the Device Selection dialog.
2983 Select the image you want to flash to the device, which
2984 should have a name in the form
2985 <product>-v<product-version>-<software-version>.ihx, such
2986 as TeleMega-v1.0-1.3.0.ihx.
2991 Make sure the configuration parameters are reasonable
2992 looking. If the serial number and/or RF configuration
2993 values aren't right, you'll need to change them.
2998 Hit the 'OK' button and the software should proceed to flash
2999 the device with new firmware, showing a progress bar.
3004 Verify that the device is working by using the 'Configure
3005 Altimeter' item to check over the configuration.
3010 <title>Recovering From Self-Flashing Failure</title>
3012 If the firmware loading fails, it can leave the device
3013 unable to boot. Not to worry, you can force the device to
3014 start the boot loader instead, which will let you try to
3015 flash the device again.
3018 On each device, connecting two pins from one of the exposed
3019 connectors will force the boot loader to start, even if the
3020 regular operating system has been corrupted in some way.
3024 <term>TeleMega</term>
3027 Connect pin 6 and pin 1 of the companion connector. Pin 1
3028 can be identified by the square pad around it, and then
3029 the pins could sequentially across the board. Be very
3030 careful to <emphasis>not</emphasis> short pin 8 to
3031 anything as that is connected directly to the battery. Pin
3032 7 carries 3.3V and the board will crash if that is
3033 connected to pin 1, but shouldn't damage the board.
3038 <term>TeleMetrum v2</term>
3041 Connect pin 6 and pin 1 of the companion connector. Pin 1
3042 can be identified by the square pad around it, and then
3043 the pins could sequentially across the board. Be very
3044 careful to <emphasis>not</emphasis> short pin 8 to
3045 anything as that is connected directly to the battery. Pin
3046 7 carries 3.3V and the board will crash if that is
3047 connected to pin 1, but shouldn't damage the board.
3052 <term>EasyMini</term>
3055 Connect pin 6 and pin 1 of the debug connector, which is
3056 the six holes next to the beeper. Pin 1 can be identified
3057 by the square pad around it, and then the pins could
3058 sequentially across the board, making Pin 6 the one on the
3059 other end of the row.
3067 <title>Pair Programming</title>
3069 The big concept to understand is that you have to use a
3070 TeleMega, TeleMetrum or TeleDongle as a programmer to update a
3071 pair programmed device. Due to limited memory resources in the
3072 cc1111, we don't support programming directly over USB for these
3077 <title>Updating TeleMetrum v1.x Firmware</title>
3078 <orderedlist inheritnum='inherit' numeration='arabic'>
3081 Find the 'programming cable' that you got as part of the starter
3082 kit, that has a red 8-pin MicroMaTch connector on one end and a
3083 red 4-pin MicroMaTch connector on the other end.
3088 Take the 2 screws out of the TeleDongle case to get access
3089 to the circuit board.
3094 Plug the 8-pin end of the programming cable to the
3095 matching connector on the TeleDongle, and the 4-pin end to the
3096 matching connector on the TeleMetrum.
3097 Note that each MicroMaTch connector has an alignment pin that
3098 goes through a hole in the PC board when you have the cable
3104 Attach a battery to the TeleMetrum board.
3109 Plug the TeleDongle into your computer's USB port, and power
3115 Run AltosUI, and select 'Flash Image' from the File menu.
3120 Pick the TeleDongle device from the list, identifying it as the
3126 Select the image you want put on the TeleMetrum, which should have a
3127 name in the form telemetrum-v1.2-1.0.0.ihx. It should be visible
3128 in the default directory, if not you may have to poke around
3129 your system to find it.
3134 Make sure the configuration parameters are reasonable
3135 looking. If the serial number and/or RF configuration
3136 values aren't right, you'll need to change them.
3141 Hit the 'OK' button and the software should proceed to flash
3142 the TeleMetrum with new firmware, showing a progress bar.
3147 Confirm that the TeleMetrum board seems to have updated OK, which you
3148 can do by plugging in to it over USB and using a terminal program
3149 to connect to the board and issue the 'v' command to check
3155 If something goes wrong, give it another try.
3161 <title>Updating TeleMini Firmware</title>
3162 <orderedlist inheritnum='inherit' numeration='arabic'>
3165 You'll need a special 'programming cable' to reprogram the
3166 TeleMini. You can make your own using an 8-pin MicroMaTch
3167 connector on one end and a set of four pins on the other.
3172 Take the 2 screws out of the TeleDongle case to get access
3173 to the circuit board.
3178 Plug the 8-pin end of the programming cable to the matching
3179 connector on the TeleDongle, and the 4-pins into the holes
3180 in the TeleMini circuit board. Note that the MicroMaTch
3181 connector has an alignment pin that goes through a hole in
3182 the PC board when you have the cable oriented correctly, and
3183 that pin 1 on the TeleMini board is marked with a square pad
3184 while the other pins have round pads.
3189 Attach a battery to the TeleMini board.
3194 Plug the TeleDongle into your computer's USB port, and power
3200 Run AltosUI, and select 'Flash Image' from the File menu.
3205 Pick the TeleDongle device from the list, identifying it as the
3211 Select the image you want put on the TeleMini, which should have a
3212 name in the form telemini-v1.0-1.0.0.ihx. It should be visible
3213 in the default directory, if not you may have to poke around
3214 your system to find it.
3219 Make sure the configuration parameters are reasonable
3220 looking. If the serial number and/or RF configuration
3221 values aren't right, you'll need to change them.
3226 Hit the 'OK' button and the software should proceed to flash
3227 the TeleMini with new firmware, showing a progress bar.
3232 Confirm that the TeleMini board seems to have updated OK, which you
3233 can do by configuring it over the radio link through the TeleDongle, or
3234 letting it come up in “flight” mode and listening for telemetry.
3239 If something goes wrong, give it another try.
3245 <title>Updating TeleDongle Firmware</title>
3247 Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
3248 firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
3250 <orderedlist inheritnum='inherit' numeration='arabic'>
3253 Find the 'programming cable' that you got as part of the starter
3254 kit, that has a red 8-pin MicroMaTch connector on one end and a
3255 red 4-pin MicroMaTch connector on the other end.
3260 Find the USB cable that you got as part of the starter kit, and
3261 plug the “mini” end in to the mating connector on TeleMetrum or TeleDongle.
3266 Take the 2 screws out of the TeleDongle case to get access
3267 to the circuit board.
3272 Plug the 8-pin end of the programming cable to the
3273 matching connector on the programmer, and the 4-pin end to the
3274 matching connector on the TeleDongle.
3275 Note that each MicroMaTch connector has an alignment pin that
3276 goes through a hole in the PC board when you have the cable
3282 Attach a battery to the TeleMetrum board if you're using one.
3287 Plug both the programmer and the TeleDongle into your computer's USB
3288 ports, and power up the programmer.
3293 Run AltosUI, and select 'Flash Image' from the File menu.
3298 Pick the programmer device from the list, identifying it as the
3304 Select the image you want put on the TeleDongle, which should have a
3305 name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
3306 in the default directory, if not you may have to poke around
3307 your system to find it.
3312 Make sure the configuration parameters are reasonable
3313 looking. If the serial number and/or RF configuration
3314 values aren't right, you'll need to change them. The TeleDongle
3315 serial number is on the “bottom” of the circuit board, and can
3316 usually be read through the translucent blue plastic case without
3317 needing to remove the board from the case.
3322 Hit the 'OK' button and the software should proceed to flash
3323 the TeleDongle with new firmware, showing a progress bar.
3328 Confirm that the TeleDongle board seems to have updated OK, which you
3329 can do by plugging in to it over USB and using a terminal program
3330 to connect to the board and issue the 'v' command to check
3331 the version, etc. Once you're happy, remove the programming cable
3332 and put the cover back on the TeleDongle.
3337 If something goes wrong, give it another try.
3342 Be careful removing the programming cable from the locking 8-pin
3343 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
3344 screwdriver or knife blade to gently pry the locking ears out
3345 slightly to extract the connector. We used a locking connector on
3346 TeleMetrum to help ensure that the cabling to companion boards
3347 used in a rocket don't ever come loose accidentally in flight.
3352 <title>Hardware Specifications</title>
3355 TeleMega Specifications
3360 Recording altimeter for model rocketry.
3365 Supports dual deployment and four auxiliary pyro channels
3366 (a total of 6 events).
3371 70cm 40mW ham-band transceiver for telemetry down-link.
3376 Barometric pressure sensor good to 100k feet MSL.
3381 1-axis high-g accelerometer for motor characterization, capable of
3387 9-axis IMU including integrated 3-axis accelerometer,
3388 3-axis gyroscope and 3-axis magnetometer.
3393 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
3398 On-board 8 Megabyte non-volatile memory for flight data storage.
3403 USB interface for battery charging, configuration, and data recovery.
3408 Fully integrated support for Li-Po rechargeable batteries.
3413 Can use either main system Li-Po or optional separate pyro battery
3419 3.25 x 1.25 inch board designed to fit inside 38mm air-frame coupler tube.
3426 TeleMetrum v2 Specifications
3431 Recording altimeter for model rocketry.
3436 Supports dual deployment (can fire 2 ejection charges).
3441 70cm, 40mW ham-band transceiver for telemetry down-link.
3446 Barometric pressure sensor good to 100k feet MSL.
3451 1-axis high-g accelerometer for motor characterization, capable of
3457 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
3462 On-board 8 Megabyte non-volatile memory for flight data storage.
3467 USB interface for battery charging, configuration, and data recovery.
3472 Fully integrated support for Li-Po rechargeable batteries.
3477 Uses Li-Po to fire e-matches, can be modified to support
3478 optional separate pyro battery if needed.
3483 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
3489 <title>TeleMetrum v1 Specifications</title>
3493 Recording altimeter for model rocketry.
3498 Supports dual deployment (can fire 2 ejection charges).
3503 70cm, 10mW ham-band transceiver for telemetry down-link.
3508 Barometric pressure sensor good to 45k feet MSL.
3513 1-axis high-g accelerometer for motor characterization, capable of
3514 +/- 50g using default part.
3519 On-board, integrated GPS receiver with 5Hz update rate capability.
3524 On-board 1 megabyte non-volatile memory for flight data storage.
3529 USB interface for battery charging, configuration, and data recovery.
3534 Fully integrated support for Li-Po rechargeable batteries.
3539 Uses Li-Po to fire e-matches, can be modified to support
3540 optional separate pyro battery if needed.
3545 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
3552 TeleMini v2.0 Specifications
3557 Recording altimeter for model rocketry.
3562 Supports dual deployment (can fire 2 ejection charges).
3567 70cm, 10mW ham-band transceiver for telemetry down-link.
3572 Barometric pressure sensor good to 100k feet MSL.
3577 On-board 1 megabyte non-volatile memory for flight data storage.
3582 USB interface for configuration, and data recovery.
3587 Support for Li-Po rechargeable batteries (using an
3588 external charger), or any 3.7-15V external battery.
3593 Uses Li-Po to fire e-matches, can be modified to support
3594 optional separate pyro battery if needed.
3599 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
3606 TeleMini v1.0 Specifications
3611 Recording altimeter for model rocketry.
3616 Supports dual deployment (can fire 2 ejection charges).
3621 70cm, 10mW ham-band transceiver for telemetry down-link.
3626 Barometric pressure sensor good to 45k feet MSL.
3631 On-board 5 kilobyte non-volatile memory for flight data storage.
3636 RF interface for configuration, and data recovery.
3641 Support for Li-Po rechargeable batteries, using an external charger.
3646 Uses Li-Po to fire e-matches, can be modified to support
3647 optional separate pyro battery if needed.
3652 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube.
3659 EasyMini Specifications
3664 Recording altimeter for model rocketry.
3669 Supports dual deployment (can fire 2 ejection charges).
3674 Barometric pressure sensor good to 100k feet MSL.
3679 On-board 1 megabyte non-volatile memory for flight data storage.
3684 USB interface for configuration, and data recovery.
3689 Support for Li-Po rechargeable batteries (using an
3690 external charger), or any 3.7-15V external battery.
3695 Uses Li-Po to fire e-matches, can be modified to support
3696 optional separate pyro battery if needed.
3701 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
3710 <emphasis>TeleMetrum seems to shut off when disconnected from the
3711 computer.</emphasis> <?linebreak?>
3712 Make sure the battery is adequately charged. Remember the
3713 unit will pull more power than the USB port can deliver before the
3714 GPS enters “locked” mode. The battery charges best when TeleMetrum
3718 <emphasis>It's impossible to stop the TeleDongle when it's in “p” mode, I have
3719 to unplug the USB cable? </emphasis><?linebreak?>
3720 Make sure you have tried to “escape out” of
3721 this mode. If this doesn't work the reboot procedure for the
3722 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
3723 outgoing buffer IF your “escape out” ('~~') does not work.
3724 At this point using either 'ao-view' (or possibly
3725 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
3729 <emphasis>The amber LED (on the TeleMetrum) lights up when both
3730 battery and USB are connected. Does this mean it's charging?
3731 </emphasis><?linebreak?>
3732 Yes, the yellow LED indicates the charging at the 'regular' rate.
3733 If the led is out but the unit is still plugged into a USB port,
3734 then the battery is being charged at a 'trickle' rate.
3737 <emphasis>There are no “dit-dah-dah-dit” sound or lights like the manual
3738 mentions?</emphasis><?linebreak?>
3739 That's the “pad” mode. Weak batteries might be the problem.
3740 It is also possible that the flight computer is horizontal and the
3742 is instead a “dit-dit” meaning 'idle'. For TeleMini, it's possible that
3743 it received a command packet which would have left it in “pad” mode.
3746 <emphasis>How do I save flight data?</emphasis><?linebreak?>
3747 Live telemetry is written to file(s) whenever AltosUI is connected
3748 to the TeleDongle. The file area defaults to ~/TeleMetrum
3749 but is easily changed using the menus in AltosUI. The files that
3750 are written end in '.telem'. The after-flight
3751 data-dumped files will end in .eeprom and represent continuous data
3752 unlike the .telem files that are subject to losses
3753 along the RF data path.
3754 See the above instructions on what and how to save the eeprom stored
3755 data after physically retrieving your altimeter. Make sure to save
3756 the on-board data after each flight; while the TeleMetrum can store
3757 multiple flights, you never know when you'll lose the altimeter...
3761 <title>Notes for Older Software</title>
3764 Before AltosUI was written, using Altus Metrum devices required
3765 some finesse with the Linux command line. There was a limited
3766 GUI tool, ao-view, which provided functionality similar to the
3767 Monitor Flight window in AltosUI, but everything else was a
3768 fairly 80's experience. This appendix includes documentation for
3769 using that software.
3773 Both TeleMetrum and TeleDongle can be directly communicated
3774 with using USB ports. The first thing you should try after getting
3775 both units plugged into to your computer's USB port(s) is to run
3776 'ao-list' from a terminal-window to see what port-device-name each
3777 device has been assigned by the operating system.
3778 You will need this information to access the devices via their
3779 respective on-board firmware and data using other command line
3780 programs in the AltOS software suite.
3783 TeleMini can be communicated with through a TeleDongle device
3784 over the radio link. When first booted, TeleMini listens for a
3785 TeleDongle device and if it receives a packet, it goes into
3786 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be
3787 launched. The easiest way to get it talking is to start the
3788 communication link on the TeleDongle and the power up the
3792 To access the device's firmware for configuration you need a terminal
3793 program such as you would use to talk to a modem. The software
3794 authors prefer using the program 'cu' which comes from the UUCP package
3795 on most Unix-like systems such as Linux. An example command line for
3796 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
3797 indicated from running the
3798 ao-list program. Another reasonable terminal program for Linux is
3799 'cutecom'. The default 'escape'
3800 character used by CU (i.e. the character you use to
3801 issue commands to cu itself instead of sending the command as input
3802 to the connected device) is a '~'. You will need this for use in
3803 only two different ways during normal operations. First is to exit
3804 the program by sending a '~.' which is called a 'escape-disconnect'
3805 and allows you to close-out from 'cu'. The
3806 second use will be outlined later.
3809 All of the Altus Metrum devices share the concept of a two level
3810 command set in their firmware.
3811 The first layer has several single letter commands. Once
3812 you are using 'cu' (or 'cutecom') sending (typing) a '?'
3813 returns a full list of these
3814 commands. The second level are configuration sub-commands accessed
3815 using the 'c' command, for
3816 instance typing 'c?' will give you this second level of commands
3817 (all of which require the
3818 letter 'c' to access). Please note that most configuration options
3819 are stored only in Flash memory; TeleDongle doesn't provide any storage
3820 for these options and so they'll all be lost when you unplug it.
3823 Try setting these configuration ('c' or second level menu) values. A good
3824 place to start is by setting your call sign. By default, the boards
3825 use 'N0CALL' which is cute, but not exactly legal!
3826 Spend a few minutes getting comfortable with the units, their
3827 firmware, and 'cu' (or possibly 'cutecom').
3828 For instance, try to send
3829 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
3830 Verify you can connect and disconnect from the units while in your
3831 terminal program by sending the escape-disconnect mentioned above.
3834 To set the radio frequency, use the 'c R' command to specify the
3835 radio transceiver configuration parameter. This parameter is computed
3836 using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
3837 the standard calibration reference frequency, 'S', (normally 434.550MHz):
3841 Round the result to the nearest integer value.
3842 As with all 'c' sub-commands, follow this with a 'c w' to write the
3843 change to the parameter block in the on-board flash on
3844 your altimeter board if you want the change to stay in place across reboots.
3847 To set the apogee delay, use the 'c d' command.
3848 As with all 'c' sub-commands, follow this with a 'c w' to write the
3849 change to the parameter block in the on-board DataFlash chip.
3852 To set the main deployment altitude, use the 'c m' command.
3853 As with all 'c' sub-commands, follow this with a 'c w' to write the
3854 change to the parameter block in the on-board DataFlash chip.
3857 To calibrate the radio frequency, connect the UHF antenna port to a
3858 frequency counter, set the board to 434.550MHz, and use the 'C'
3859 command to generate a CW carrier. Wait for the transmitter temperature
3860 to stabilize and the frequency to settle down.
3861 Then, divide 434.550 MHz by the
3862 measured frequency and multiply by the current radio cal value show
3863 in the 'c s' command. For an unprogrammed board, the default value
3864 is 1186611. Take the resulting integer and program it using the 'c f'
3865 command. Testing with the 'C' command again should show a carrier
3866 within a few tens of Hertz of the intended frequency.
3867 As with all 'c' sub-commands, follow this with a 'c w' to write the
3868 change to the parameter block in the on-board DataFlash chip.
3871 Note that the 'reboot' command, which is very useful on the altimeters,
3872 will likely just cause problems with the dongle. The *correct* way
3873 to reset the dongle is just to unplug and re-plug it.
3876 A fun thing to do at the launch site and something you can do while
3877 learning how to use these units is to play with the radio link access
3878 between an altimeter and the TeleDongle. Be aware that you *must* create
3879 some physical separation between the devices, otherwise the link will
3880 not function due to signal overload in the receivers in each device.
3883 Now might be a good time to take a break and read the rest of this
3884 manual, particularly about the two “modes” that the altimeters
3885 can be placed in. TeleMetrum uses the position of the device when booting
3886 up will determine whether the unit is in “pad” or “idle” mode. TeleMini
3887 enters “idle” mode when it receives a command packet within the first 5 seconds
3888 of being powered up, otherwise it enters “pad” mode.
3891 You can access an altimeter in idle mode from the TeleDongle's USB
3892 connection using the radio link
3893 by issuing a 'p' command to the TeleDongle. Practice connecting and
3894 disconnecting ('~~' while using 'cu') from the altimeter. If
3895 you cannot escape out of the “p” command, (by using a '~~' when in
3896 CU) then it is likely that your kernel has issues. Try a newer version.
3899 Using this radio link allows you to configure the altimeter, test
3900 fire e-matches and igniters from the flight line, check pyro-match
3901 continuity and so forth. You can leave the unit turned on while it
3902 is in 'idle mode' and then place the
3903 rocket vertically on the launch pad, walk away and then issue a
3904 reboot command. The altimeter will reboot and start sending data
3905 having changed to the “pad” mode. If the TeleDongle is not receiving
3906 this data, you can disconnect 'cu' from the TeleDongle using the
3907 procedures mentioned above and THEN connect to the TeleDongle from
3908 inside 'ao-view'. If this doesn't work, disconnect from the
3909 TeleDongle, unplug it, and try again after plugging it back in.
3912 In order to reduce the chance of accidental firing of pyrotechnic
3913 charges, the command to fire a charge is intentionally somewhat
3914 difficult to type, and the built-in help is slightly cryptic to
3915 prevent accidental echoing of characters from the help text back at
3916 the board from firing a charge. The command to fire the apogee
3917 drogue charge is 'i DoIt drogue' and the command to fire the main
3918 charge is 'i DoIt main'.
3921 On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
3922 and 'ao-view' will both auditorily announce and visually indicate
3924 Now you can launch knowing that you have a good data path and
3925 good satellite lock for flight data and recovery. Remember
3926 you MUST tell ao-view to connect to the TeleDongle explicitly in
3927 order for ao-view to be able to receive data.
3930 The altimeters provide RDF (radio direction finding) tones on
3931 the pad, during descent and after landing. These can be used to
3932 locate the rocket using a directional antenna; the signal
3933 strength providing an indication of the direction from receiver to rocket.
3936 TeleMetrum also provides GPS tracking data, which can further simplify
3937 locating the rocket once it has landed. (The last good GPS data
3938 received before touch-down will be on the data screen of 'ao-view'.)
3941 Once you have recovered the rocket you can download the eeprom
3942 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
3943 either a USB cable or over the radio link using TeleDongle.
3944 And by following the man page for 'ao-postflight' you can create
3945 various data output reports, graphs, and even KML data to see the
3946 flight trajectory in Google-earth. (Moving the viewing angle making
3947 sure to connect the yellow lines while in Google-earth is the proper
3951 As for ao-view.... some things are in the menu but don't do anything
3952 very useful. The developers have stopped working on ao-view to focus
3953 on a new, cross-platform ground station program. So ao-view may or
3954 may not be updated in the future. Mostly you just use
3955 the Log and Device menus. It has a wonderful display of the incoming
3956 flight data and I am sure you will enjoy what it has to say to you
3957 once you enable the voice output!
3961 <title>Drill Templates</title>
3963 These images, when printed, provide precise templates for the
3964 mounting holes in Altus Metrum flight computers
3967 <title>TeleMega template</title>
3969 TeleMega has overall dimensions of 1.250 x 3.250 inches, and
3970 the mounting holes are sized for use with 4-40 or M3 screws.
3972 <mediaobject id="TeleMegaTemplate">
3974 <imagedata format="SVG" fileref="telemega-outline.svg"/>
3979 <title>TeleMetrum template</title>
3981 TeleMetrum has overall dimensions of 1.000 x 2.750 inches, and the
3982 mounting holes are sized for use with 4-40 or M3 screws.
3984 <mediaobject id="TeleMetrumTemplate">
3986 <imagedata format="SVG" fileref="telemetrum.svg"/>
3991 <title>TeleMini v2/EasyMini template</title>
3993 TeleMini v2 and EasyMini have overall dimensions of 0.800 x 1.500 inches, and the
3994 mounting holes are sized for use with 4-40 or M3 screws.
3996 <mediaobject id="MiniTemplate">
3998 <imagedata format="SVG" fileref="easymini-outline.svg"/>
4003 <title>TeleMini v1 template</title>
4005 TeleMini has overall dimensions of 0.500 x 1.500 inches, and the
4006 mounting holes are sized for use with 2-56 or M2 screws.
4008 <mediaobject id="TeleMiniTemplate">
4010 <imagedata format="SVG" fileref="telemini.svg"/>
4016 <title>Calibration</title>
4018 There are only two calibrations required for TeleMetrum and
4019 TeleMega, and only one for TeleDongle, TeleMini and EasyMini.
4020 All boards are shipped from the factory pre-calibrated, but
4021 the procedures are documented here in case they are ever
4022 needed. Re-calibration is not supported by AltosUI, you must
4023 connect to the board with a serial terminal program and
4024 interact directly with the on-board command interpreter to
4028 <title>Radio Frequency</title>
4030 The radio frequency is synthesized from a clock based on the
4031 crystal on the board. The actual frequency of this oscillator
4032 must be measured to generate a calibration constant. While our
4034 bandwidth is wide enough to allow boards to communicate even when
4035 their oscillators are not on exactly the same frequency, performance
4036 is best when they are closely matched.
4037 Radio frequency calibration requires a calibrated frequency counter.
4038 Fortunately, once set, the variation in frequency due to aging and
4039 temperature changes is small enough that re-calibration by customers
4040 should generally not be required.
4043 To calibrate the radio frequency, connect the UHF antenna
4044 port to a frequency counter, set the board to 434.550MHz,
4045 and use the 'C' command in the on-board command interpreter
4046 to generate a CW carrier. For USB-enabled boards, this is
4047 best done over USB. For TeleMini v1, note that the only way
4048 to escape the 'C' command is via power cycle since the board
4049 will no longer be listening for commands once it starts
4050 generating a CW carrier.
4053 Wait for the transmitter temperature to stabilize and the frequency
4054 to settle down. Then, divide 434.550 MHz by the
4055 measured frequency and multiply by the current radio cal value show
4056 in the 'c s' command. For an unprogrammed board, the default value
4057 is 1186611. Take the resulting integer and program it using the 'c f'
4058 command. Testing with the 'C' command again should show a carrier
4059 within a few tens of Hertz of the intended frequency.
4060 As with all 'c' sub-commands, follow this with a 'c w' to write the
4061 change to the parameter block in the on-board storage chip.
4064 Note that any time you re-do the radio frequency calibration, the
4065 radio frequency is reset to the default 434.550 Mhz. If you want
4066 to use another frequency, you will have to set that again after
4067 calibration is completed.
4071 <title>TeleMetrum and TeleMega Accelerometers</title>
4073 While barometric sensors are factory-calibrated,
4074 accelerometers are not, and so each must be calibrated once
4075 installed in a flight computer. Explicitly calibrating the
4076 accelerometers also allows us to load any compatible device.
4077 We perform a two-point calibration using gravity.
4080 To calibrate the acceleration sensor, use the 'c a 0' command. You
4081 will be prompted to orient the board vertically with the UHF antenna
4082 up and press a key, then to orient the board vertically with the
4083 UHF antenna down and press a key. Note that the accuracy of this
4084 calibration depends primarily on how perfectly vertical and still
4085 the board is held during the cal process. As with all 'c'
4086 sub-commands, follow this with a 'c w' to write the
4087 change to the parameter block in the on-board DataFlash chip.
4090 The +1g and -1g calibration points are included in each telemetry
4091 frame and are part of the header stored in onboard flash to be
4092 downloaded after flight. We always store and return raw ADC
4093 samples for each sensor... so nothing is permanently “lost” or
4094 “damaged” if the calibration is poor.
4097 In the unlikely event an accel cal goes badly, it is possible
4098 that TeleMetrum or TeleMega may always come up in 'pad mode'
4099 and as such not be listening to either the USB or radio link.
4100 If that happens, there is a special hook in the firmware to
4101 force the board back in to 'idle mode' so you can re-do the
4102 cal. To use this hook, you just need to ground the SPI clock
4103 pin at power-on. This pin is available as pin 2 on the 8-pin
4104 companion connector, and pin 1 is ground. So either
4105 carefully install a fine-gauge wire jumper between the two
4106 pins closest to the index hole end of the 8-pin connector, or
4107 plug in the programming cable to the 8-pin connector and use
4108 a small screwdriver or similar to short the two pins closest
4109 to the index post on the 4-pin end of the programming cable,
4110 and power up the board. It should come up in 'idle mode'
4111 (two beeps), allowing a re-cal.
4116 <title>Release Notes</title>
4118 <title>Version 1.3</title>
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4121 href="release-notes-1.3.xsl"
4122 xpointer="xpointer(/article/*)"/>
4125 <title>Version 1.2.1</title>
4127 xmlns:xi="http://www.w3.org/2001/XInclude"
4128 href="release-notes-1.2.1.xsl"
4129 xpointer="xpointer(/article/*)"/>
4132 <title>Version 1.2</title>
4134 xmlns:xi="http://www.w3.org/2001/XInclude"
4135 href="release-notes-1.2.xsl"
4136 xpointer="xpointer(/article/*)"/>
4139 <title>Version 1.1.1</title>
4141 xmlns:xi="http://www.w3.org/2001/XInclude"
4142 href="release-notes-1.1.1.xsl"
4143 xpointer="xpointer(/article/*)"/>
4146 <title>Version 1.1</title>
4148 xmlns:xi="http://www.w3.org/2001/XInclude"
4149 href="release-notes-1.1.xsl"
4150 xpointer="xpointer(/article/*)"/>
4153 <title>Version 1.0.1</title>
4155 xmlns:xi="http://www.w3.org/2001/XInclude"
4156 href="release-notes-1.0.1.xsl"
4157 xpointer="xpointer(/article/*)"/>
4160 <title>Version 0.9.2</title>
4162 xmlns:xi="http://www.w3.org/2001/XInclude"
4163 href="release-notes-0.9.2.xsl"
4164 xpointer="xpointer(/article/*)"/>
4167 <title>Version 0.9</title>
4169 xmlns:xi="http://www.w3.org/2001/XInclude"
4170 href="release-notes-0.9.xsl"
4171 xpointer="xpointer(/article/*)"/>
4174 <title>Version 0.8</title>
4176 xmlns:xi="http://www.w3.org/2001/XInclude"
4177 href="release-notes-0.8.xsl"
4178 xpointer="xpointer(/article/*)"/>
4181 <title>Version 0.7.1</title>
4183 xmlns:xi="http://www.w3.org/2001/XInclude"
4184 href="release-notes-0.7.1.xsl"
4185 xpointer="xpointer(/article/*)"/>
4190 <!-- LocalWords: Altusmetrum
projects / fw / altos / blob