1 <?xml version="1.0" encoding="utf-8"?>
2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
3 "/usr/share/xml/docbook/schema/dtd/4.5/docbookx.dtd">
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>1.3.2</revnumber>
40 <date>24 January 2014</date>
42 Bug fixes for TeleMega and AltosUI.
46 <revnumber>1.3.1</revnumber>
47 <date>21 January 2014</date>
49 Bug fixes for TeleMega and TeleMetrum v2.0 along with a few
50 small UI improvements.
54 <revnumber>1.3</revnumber>
55 <date>12 November 2013</date>
57 Updated for software version 1.3. Version 1.3 adds support
58 for TeleMega, TeleMetrum v2.0, TeleMini v2.0 and EasyMini
59 and fixes bugs in AltosUI and the AltOS firmware.
63 <revnumber>1.2.1</revnumber>
64 <date>21 May 2013</date>
66 Updated for software version 1.2. Version 1.2 adds support
67 for TeleBT and AltosDroid. It also adds a few minor features
68 and fixes bugs in AltosUI and the AltOS firmware.
72 <revnumber>1.2</revnumber>
73 <date>18 April 2013</date>
75 Updated for software version 1.2. Version 1.2 adds support
76 for MicroPeak and the MicroPeak USB interface.
80 <revnumber>1.1.1</revnumber>
81 <date>16 September 2012</date>
83 Updated for software version 1.1.1 Version 1.1.1 fixes a few
84 bugs found in version 1.1.
88 <revnumber>1.1</revnumber>
89 <date>13 September 2012</date>
91 Updated for software version 1.1. Version 1.1 has new
92 features but is otherwise compatible with version 1.0.
96 <revnumber>1.0</revnumber>
97 <date>24 August 2011</date>
99 Updated for software version 1.0. Note that 1.0 represents a
100 telemetry format change, meaning both ends of a link
101 (TeleMetrum/TeleMini and TeleDongle) must be updated or
102 communications will fail.
106 <revnumber>0.9</revnumber>
107 <date>18 January 2011</date>
109 Updated for software version 0.9. Note that 0.9 represents a
110 telemetry format change, meaning both ends of a link (TeleMetrum and
111 TeleDongle) must be updated or communications will fail.
115 <revnumber>0.8</revnumber>
116 <date>24 November 2010</date>
117 <revremark>Updated for software version 0.8 </revremark>
122 <title>Acknowledgments</title>
124 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing “The
125 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
126 Kit” which formed the basis of the original Getting Started chapter
127 in this manual. Bob was one of our first customers for a production
128 TeleMetrum, and his continued enthusiasm and contributions
129 are immensely gratifying and highly appreciated!
132 And thanks to Anthony (AJ) Towns for major contributions including
133 the AltosUI graphing and site map code and associated documentation.
134 Free software means that our customers and friends can become our
135 collaborators, and we certainly appreciate this level of
139 Have fun using these products, and we hope to meet all of you
140 out on the rocket flight line somewhere.
143 NAR #87103, TRA #12201
145 Keith Packard, KD7SQG
146 NAR #88757, TRA #12200
151 <title>Introduction and Overview</title>
153 Welcome to the Altus Metrum community! Our circuits and software reflect
154 our passion for both hobby rocketry and Free Software. We hope their
155 capabilities and performance will delight you in every way, but by
156 releasing all of our hardware and software designs under open licenses,
157 we also hope to empower you to take as active a role in our collective
161 The first device created for our community was TeleMetrum, a dual
162 deploy altimeter with fully integrated GPS and radio telemetry
163 as standard features, and a “companion interface” that will
164 support optional capabilities in the future. The latest version
165 of TeleMetrum, v2.0, has all of the same features but with
166 improved sensors and radio to offer increased performance.
169 Our second device was TeleMini, a dual deploy altimeter with
170 radio telemetry and radio direction finding. The first version
171 of this device was only 13mm by 38mm (½ inch by 1½ inches) and
172 could fit easily in an 18mm air-frame. The latest version, v2.0,
173 includes a beeper, USB data download and extended on-board
174 flight logging, along with an improved barometric sensor.
177 TeleMega is our most sophisticated device, including six pyro
178 channels (four of which are fully programmable), integrated GPS,
179 integrated gyroscopes for staging/air-start inhibit and high
180 performance telemetry.
183 EasyMini is a dual-deploy altimeter with logging and built-in
187 TeleDongle was our first ground station, providing a USB to RF
188 interfaces for communicating with the altimeters. Combined with
189 your choice of antenna and notebook computer, TeleDongle and our
190 associated user interface software form a complete ground
191 station capable of logging and displaying in-flight telemetry,
192 aiding rocket recovery, then processing and archiving flight
193 data for analysis and review.
196 For a slightly more portable ground station experience that also
197 provides direct rocket recovery support, TeleBT offers flight
198 monitoring and data logging using a Bluetooth™ connection between
199 the receiver and an Android device that has the AltosDroid
200 application installed from the Google Play store.
203 More products will be added to the Altus Metrum family over time, and
204 we currently envision that this will be a single, comprehensive manual
205 for the entire product family.
209 <title>Getting Started</title>
211 The first thing to do after you check the inventory of parts in your
212 “starter kit” is to charge the battery.
215 For TeleMetrum and TeleMega, the battery can be charged by plugging it into the
216 corresponding socket of the device and then using the USB
217 cable to plug the flight computer into your computer's USB socket. The
218 on-board circuitry will charge the battery whenever it is plugged
219 in, because the on-off switch does NOT control the
223 On TeleMetrum v1 boards, when the GPS chip is initially
224 searching for satellites, TeleMetrum will consume more current
225 than it pulls from the USB port, so the battery must be
226 attached in order to get satellite lock. Once GPS is locked,
227 the current consumption goes back down enough to enable charging
228 while running. So it's a good idea to fully charge the battery
229 as your first item of business so there is no issue getting and
230 maintaining satellite lock. The yellow charge indicator led
231 will go out when the battery is nearly full and the charger goes
232 to trickle charge. It can take several hours to fully recharge a
233 deeply discharged battery.
236 TeleMetrum v2.0 and TeleMega use a higher power battery charger,
237 allowing them to charge the battery while running the board at
238 maximum power. When the battery is charging, or when the board
239 is consuming a lot of power, the red LED will be lit. When the
240 battery is fully charged, the green LED will be lit. When the
241 battery is damaged or missing, both LEDs will be lit, which
245 The Lithium Polymer TeleMini and EasyMini battery can be charged by
246 disconnecting it from the board and plugging it into a
247 standalone battery charger such as the LipoCharger product
248 included in TeleMini Starter Kits, and connecting that via a USB
249 cable to a laptop or other USB power source.
252 You can also choose to use another battery with TeleMini v2.0
253 and EasyMini, anything supplying between 4 and 12 volts should
254 work fine (like a standard 9V battery), but if you are planning
255 to fire pyro charges, ground testing is required to verify that
256 the battery supplies enough current to fire your chosen e-matches.
259 The other active device in the starter kit is the TeleDongle USB to
260 RF interface. If you plug it in to your Mac or Linux computer it should
261 “just work”, showing up as a serial port device. Windows systems need
262 driver information that is part of the AltOS download to know that the
263 existing USB modem driver will work. We therefore recommend installing
264 our software before plugging in TeleDongle if you are using a Windows
265 computer. If you are using an older version of Linux and are having
266 problems, try moving to a fresher kernel (2.6.33 or newer).
269 Next you should obtain and install the AltOS software. The AltOS
270 distribution includes the AltosUI ground station program, current
272 images for all of the hardware, and a number of standalone
273 utilities that are rarely needed. Pre-built binary packages are
274 available for Linux, Microsoft Windows, and recent MacOSX
275 versions. Full source code and build instructions are also
276 available. The latest version may always be downloaded from
277 <ulink url="http://altusmetrum.org/AltOS"/>.
280 If you're using a TeleBT instead of the TeleDongle, you'll want to
281 install the AltosDroid application from the Google Play store on an
282 Android device. You don't need a data plan to use AltosDroid, but
283 without network access, the Map view will be less useful as it
284 won't contain any map data. You can also use TeleBT connected
285 over USB with your laptop computer; it acts exactly like a
286 TeleDongle. Anywhere this manual talks about TeleDongle, you can
287 also read that as 'and TeleBT when connected via USB'.
291 <title>Handling Precautions</title>
293 All Altus Metrum products are sophisticated electronic devices.
294 When handled gently and properly installed in an air-frame, they
295 will deliver impressive results. However, as with all electronic
296 devices, there are some precautions you must take.
299 The Lithium Polymer rechargeable batteries have an
300 extraordinary power density. This is great because we can fly with
301 much less battery mass than if we used alkaline batteries or previous
302 generation rechargeable batteries... but if they are punctured
303 or their leads are allowed to short, they can and will release their
305 Thus we recommend that you take some care when handling our batteries
306 and consider giving them some extra protection in your air-frame. We
307 often wrap them in suitable scraps of closed-cell packing foam before
308 strapping them down, for example.
311 The barometric sensors used on all of our flight computers are
312 sensitive to sunlight. In normal mounting situations, the baro sensor
313 and all of the other surface mount components
314 are “down” towards whatever the underlying mounting surface is, so
315 this is not normally a problem. Please consider this when designing an
316 installation in an air-frame with a see-through plastic payload bay. It
317 is particularly important to
318 consider this with TeleMini v1.0, both because the baro sensor is on the
319 “top” of the board, and because many model rockets with payload bays
320 use clear plastic for the payload bay! Replacing these with an opaque
321 cardboard tube, painting them, or wrapping them with a layer of masking
322 tape are all reasonable approaches to keep the sensor out of direct
326 The barometric sensor sampling port must be able to “breathe”,
327 both by not being covered by foam or tape or other materials that might
328 directly block the hole on the top of the sensor, and also by having a
329 suitable static vent to outside air.
332 As with all other rocketry electronics, Altus Metrum altimeters must
333 be protected from exposure to corrosive motor exhaust and ejection
338 <title>Altus Metrum Hardware</title>
340 <title>Overview</title>
342 Here's the full set of Altus Metrum products, both in
343 production and retired.
346 <title>Altus Metrum Electronics</title>
347 <?dbfo keep-together="always"?>
348 <tgroup cols='8' align='center' colsep='1' rowsep='1'>
349 <colspec align='center' colwidth='*' colname='Device'/>
350 <colspec align='center' colwidth='*' colname='Barometer'/>
351 <colspec align='center' colwidth='*' colname='Z-axis accelerometer'/>
352 <colspec align='center' colwidth='*' colname='GPS'/>
353 <colspec align='center' colwidth='*' colname='3D sensors'/>
354 <colspec align='center' colwidth='*' colname='Storage'/>
355 <colspec align='center' colwidth='*' colname='RF'/>
356 <colspec align='center' colwidth='*' colname='Battery'/>
359 <entry align='center'>Device</entry>
360 <entry align='center'>Barometer</entry>
361 <entry align='center'>Z-axis accelerometer</entry>
362 <entry align='center'>GPS</entry>
363 <entry align='center'>3D sensors</entry>
364 <entry align='center'>Storage</entry>
365 <entry align='center'>RF Output</entry>
366 <entry align='center'>Battery</entry>
371 <entry>TeleMetrum v1.0</entry>
372 <entry><para>MP3H6115 10km (33k')</para></entry>
373 <entry><para>MMA2202 50g</para></entry>
374 <entry>SkyTraq</entry>
381 <entry>TeleMetrum v1.1</entry>
382 <entry><para>MP3H6115 10km (33k')</para></entry>
383 <entry><para>MMA2202 50g</para></entry>
384 <entry>SkyTraq</entry>
391 <entry>TeleMetrum v1.2</entry>
392 <entry><para>MP3H6115 10km (33k')</para></entry>
393 <entry><para>ADXL78 70g</para></entry>
394 <entry>SkyTraq</entry>
401 <entry>TeleMetrum v2.0</entry>
402 <entry><para>MS5607 30km (100k')</para></entry>
403 <entry><para>MMA6555 102g</para></entry>
404 <entry>uBlox Max-7Q</entry>
411 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
412 <entry><para>MP3H6115 10km (33k')</para></entry>
421 <entry>TeleMini <?linebreak?>v2.0</entry>
422 <entry><para>MS5607 30km (100k')</para></entry>
428 <entry>3.7-12V</entry>
431 <entry>EasyMini <?linebreak?>v1.0</entry>
432 <entry><para>MS5607 30km (100k')</para></entry>
438 <entry>3.7-12V</entry>
441 <entry>TeleMega <?linebreak?>v1.0</entry>
442 <entry><para>MS5607 30km (100k')</para></entry>
443 <entry><para>MMA6555 102g</para></entry>
444 <entry>uBlox Max-7Q</entry>
445 <entry><para>MPU6000 HMC5883</para></entry>
454 <title>Altus Metrum Boards</title>
455 <?dbfo keep-together="always"?>
456 <tgroup cols='6' align='center' colsep='1' rowsep='1'>
457 <colspec align='center' colwidth='*' colname='Device'/>
458 <colspec align='center' colwidth='*' colname='Connectors'/>
459 <colspec align='center' colwidth='*' colname='Screw Terminals'/>
460 <colspec align='center' colwidth='*' colname='Width'/>
461 <colspec align='center' colwidth='*' colname='Length'/>
462 <colspec align='center' colwidth='*' colname='Tube Size'/>
465 <entry align='center'>Device</entry>
466 <entry align='center'>Connectors</entry>
467 <entry align='center'>Screw Terminals</entry>
468 <entry align='center'>Width</entry>
469 <entry align='center'>Length</entry>
470 <entry align='center'>Tube Size</entry>
475 <entry>TeleMetrum</entry>
479 Companion<?linebreak?>
483 <entry><para>Apogee pyro <?linebreak?>Main pyro <?linebreak?>Switch</para></entry>
484 <entry>1 inch (2.54cm)</entry>
485 <entry>2 ¾ inch (6.99cm)</entry>
486 <entry>29mm coupler</entry>
489 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
496 Apogee pyro <?linebreak?>
499 <entry>½ inch (1.27cm)</entry>
500 <entry>1½ inch (3.81cm)</entry>
501 <entry>18mm coupler</entry>
504 <entry>TeleMini <?linebreak?>v2.0</entry>
512 Apogee pyro <?linebreak?>
513 Main pyro <?linebreak?>
514 Battery <?linebreak?>
517 <entry>0.8 inch (2.03cm)</entry>
518 <entry>1½ inch (3.81cm)</entry>
519 <entry>24mm coupler</entry>
522 <entry>EasyMini</entry>
529 Apogee pyro <?linebreak?>
530 Main pyro <?linebreak?>
531 Battery <?linebreak?>
534 <entry>0.8 inch (2.03cm)</entry>
535 <entry>1½ inch (3.81cm)</entry>
536 <entry>24mm coupler</entry>
539 <entry>TeleMega</entry>
543 Companion<?linebreak?>
548 Apogee pyro <?linebreak?>
549 Main pyro<?linebreak?>
550 Pyro A-D<?linebreak?>
554 <entry>1¼ inch (3.18cm)</entry>
555 <entry>3¼ inch (8.26cm)</entry>
556 <entry>38mm coupler</entry>
563 <title>TeleMetrum</title>
567 <imagedata fileref="telemetrum-v1.1-thside.jpg" width="5.5in" scalefit="1"/>
572 TeleMetrum is a 1 inch by 2¾ inch circuit board. It was designed to
573 fit inside coupler for 29mm air-frame tubing, but using it in a tube that
574 small in diameter may require some creativity in mounting and wiring
575 to succeed! The presence of an accelerometer means TeleMetrum should
576 be aligned along the flight axis of the airframe, and by default the ¼
577 wave UHF wire antenna should be on the nose-cone end of the board. The
578 antenna wire is about 7 inches long, and wiring for a power switch and
579 the e-matches for apogee and main ejection charges depart from the
580 fin can end of the board, meaning an ideal “simple” avionics
581 bay for TeleMetrum should have at least 10 inches of interior length.
585 <title>TeleMini</title>
589 <imagedata fileref="telemini-v1-top.jpg" width="5.5in" scalefit="1"/>
594 TeleMini v1.0 is ½ inches by 1½ inches. It was
595 designed to fit inside an 18mm air-frame tube, but using it in
596 a tube that small in diameter may require some creativity in
597 mounting and wiring to succeed! Since there is no
598 accelerometer, TeleMini can be mounted in any convenient
599 orientation. The default ¼ wave UHF wire antenna attached to
600 the center of one end of the board is about 7 inches long. Two
601 wires for the power switch are connected to holes in the
602 middle of the board. Screw terminals for the e-matches for
603 apogee and main ejection charges depart from the other end of
604 the board, meaning an ideal “simple” avionics bay for TeleMini
605 should have at least 9 inches of interior length.
610 <imagedata fileref="telemini-v2-top.jpg" width="5.5in" scalefit="1"/>
615 TeleMini v2.0 is 0.8 inches by 1½ inches. It adds more
616 on-board data logging memory, a built-in USB connector and
617 screw terminals for the battery and power switch. The larger
618 board fits in a 24mm coupler. There's also a battery connector
619 for a LiPo battery if you want to use one of those.
623 <title>EasyMini</title>
627 <imagedata fileref="easymini-top.jpg" width="5.5in" scalefit="1"/>
632 EasyMini is built on a 0.8 inch by 1½ inch circuit board. It's
633 designed to fit in a 24mm coupler tube. The connectors and
634 screw terminals match TeleMini v2.0, so you can easily swap between
635 EasyMini and TeleMini.
639 <title>TeleMega</title>
643 <imagedata fileref="telemega-v1.0-top.jpg" width="5.5in" scalefit="1"/>
648 TeleMega is a 1¼ inch by 3¼ inch circuit board. It was
649 designed to easily fit in a 38mm coupler. Like TeleMetrum,
650 TeleMega has an accelerometer and so it must be mounted so that
651 the board is aligned with the flight axis. It can be mounted
652 either antenna up or down.
656 <title>Flight Data Recording</title>
658 Each flight computer logs data at 100 samples per second
659 during ascent and 10 samples per second during descent, except
660 for TeleMini v1.0, which records ascent at 10 samples per
661 second and descent at 1 sample per second. Data are logged to
662 an on-board flash memory part, which can be partitioned into
663 several equal-sized blocks, one for each flight.
666 <title>Data Storage on Altus Metrum altimeters</title>
667 <?dbfo keep-together="always"?>
668 <tgroup cols='4' align='center' colsep='1' rowsep='1'>
669 <colspec align='center' colwidth='*' colname='Device'/>
670 <colspec align='center' colwidth='*' colname='Bytes per sample'/>
671 <colspec align='center' colwidth='*' colname='Total storage'/>
672 <colspec align='center' colwidth='*' colname='Minutes of
676 <entry align='center'>Device</entry>
677 <entry align='center'>Bytes per Sample</entry>
678 <entry align='center'>Total Storage</entry>
679 <entry align='center'>Minutes at Full Rate</entry>
684 <entry>TeleMetrum v1.0</entry>
690 <entry>TeleMetrum v1.1 v1.2</entry>
696 <entry>TeleMetrum v2.0</entry>
702 <entry>TeleMini v1.0</entry>
708 <entry>TeleMini v2.0</entry>
714 <entry>EasyMini</entry>
720 <entry>TeleMega</entry>
729 The on-board flash is partitioned into separate flight logs,
730 each of a fixed maximum size. Increase the maximum size of
731 each log and you reduce the number of flights that can be
732 stored. Decrease the size and you can store more flights.
735 Configuration data is also stored in the flash memory on
736 TeleMetrum v1.x, TeleMini and EasyMini. This consumes 64kB
737 of flash space. This configuration space is not available
738 for storing flight log data. TeleMetrum v2.0 and TeleMega
739 store configuration data in a bit of eeprom available within
740 the processor chip, leaving that space available in flash for
744 To compute the amount of space needed for a single flight, you
745 can multiply the expected ascent time (in seconds) by 100
746 times bytes-per-sample, multiply the expected descent time (in
747 seconds) by 10 times the bytes per sample and add the two
748 together. That will slightly under-estimate the storage (in
749 bytes) needed for the flight. For instance, a TeleMetrum v2.0 flight spending
750 20 seconds in ascent and 150 seconds in descent will take
751 about (20 * 1600) + (150 * 160) = 56000 bytes of storage. You
752 could store dozens of these flights in the on-board flash.
755 The default size allows for several flights on each flight
756 computer, except for TeleMini v1.0, which only holds data for a
757 single flight. You can adjust the size.
760 Altus Metrum flight computers will not overwrite existing
761 flight data, so be sure to download flight data and erase it
762 from the flight computer before it fills up. The flight
763 computer will still successfully control the flight even if it
764 cannot log data, so the only thing you will lose is the data.
768 <title>Installation</title>
770 A typical installation involves attaching
771 only a suitable battery, a single pole switch for
772 power on/off, and two pairs of wires connecting e-matches for the
773 apogee and main ejection charges. All Altus Metrum products are
774 designed for use with single-cell batteries with 3.7 volts
775 nominal. TeleMini v2.0 and EasyMini may also be used with other
776 batteries as long as they supply between 4 and 12 volts.
779 The battery connectors are a standard 2-pin JST connector and
780 match batteries sold by Spark Fun. These batteries are
781 single-cell Lithium Polymer batteries that nominally provide 3.7
782 volts. Other vendors sell similar batteries for RC aircraft
783 using mating connectors, however the polarity for those is
784 generally reversed from the batteries used by Altus Metrum
785 products. In particular, the Tenergy batteries supplied for use
786 in Featherweight flight computers are not compatible with Altus
787 Metrum flight computers or battery chargers. <emphasis>Check
788 polarity and voltage before connecting any battery not purchased
789 from Altus Metrum or Spark Fun.</emphasis>
792 By default, we use the unregulated output of the battery directly
793 to fire ejection charges. This works marvelously with standard
794 low-current e-matches like the J-Tek from MJG Technologies, and with
795 Quest Q2G2 igniters. However, if you want or need to use a separate
796 pyro battery, check out the “External Pyro Battery” section in this
797 manual for instructions on how to wire that up. The altimeters are
798 designed to work with an external pyro battery of no more than 15 volts.
802 Ejection charges are wired directly to the screw terminal block
803 at the aft end of the altimeter. You'll need a very small straight
804 blade screwdriver for these screws, such as you might find in a
805 jeweler's screwdriver set.
808 Except for TeleMini v1.0, the flight computers also use the
809 screw terminal block for the power switch leads. On TeleMini v1.0,
810 the power switch leads are soldered directly to the board and
811 can be connected directly to a switch.
814 For most air-frames, the integrated antennas are more than
815 adequate. However, if you are installing in a carbon-fiber or
816 metal electronics bay which is opaque to RF signals, you may need to
817 use off-board external antennas instead. In this case, you can
818 replace the stock UHF antenna wire with an edge-launched SMA connector,
819 and, on TeleMetrum v1, you can unplug the integrated GPS
820 antenna and select an appropriate off-board GPS antenna with
821 cable terminating in a U.FL connector.
826 <title>System Operation</title>
828 <title>Firmware Modes </title>
830 The AltOS firmware build for the altimeters has two
831 fundamental modes, “idle” and “flight”. Which of these modes
832 the firmware operates in is determined at start up time. For
833 TeleMetrum and TeleMega, which have accelerometers, the mode is
834 controlled by the orientation of the
835 rocket (well, actually the board, of course...) at the time
836 power is switched on. If the rocket is “nose up”, then
837 the flight computer assumes it's on a rail or rod being prepared for
838 launch, so the firmware chooses flight mode. However, if the
839 rocket is more or less horizontal, the firmware instead enters
840 idle mode. Since TeleMini v2.0 and EasyMini don't have an
841 accelerometer we can use to determine orientation, “idle” mode
842 is selected if the board is connected via USB to a computer,
843 otherwise the board enters “flight” mode. TeleMini v1.0
844 selects “idle” mode if it receives a command packet within the
845 first five seconds of operation.
848 At power on, you will hear three beeps or see three flashes
849 (“S” in Morse code for start up) and then a pause while
850 the altimeter completes initialization and self test, and decides
851 which mode to enter next.
854 Here's a short summary of all of the modes and the beeping (or
855 flashing, in the case of TeleMini v1) that accompanies each
856 mode. In the description of the beeping pattern, “dit” means a
857 short beep while "dah" means a long beep (three times as
858 long). “Brap” means a long dissonant tone.
860 <title>AltOS Modes</title>
861 <?dbfo keep-together="always"?>
862 <tgroup cols='4' align='center' colsep='1' rowsep='1'>
863 <colspec align='center' colwidth='*' colname='Mode Name'/>
864 <colspec align='center' colwidth='*' colname='Letter'/>
865 <colspec align='center' colwidth='*' colname='Beeps'/>
866 <colspec align='center' colwidth='*' colname='Description'/>
869 <entry>Mode Name</entry>
870 <entry>Abbreviation</entry>
872 <entry>Description</entry>
877 <entry>Startup</entry>
879 <entry>dit dit dit</entry>
882 Calibrating sensors, detecting orientation.
889 <entry>dit dit</entry>
892 Ready to accept commands over USB or radio link.
899 <entry>dit dah dah dit</entry>
902 Waiting for launch. Not listening for commands.
909 <entry>dah dit dit dit</entry>
912 Accelerating upwards.
919 <entry>dit dit dah dit</entry>
922 Decellerating, but moving faster than 200m/s.
929 <entry>dah dit dah dit</entry>
932 Decellerating, moving slower than 200m/s
937 <entry>Drogue</entry>
939 <entry>dah dit dit</entry>
942 Descending after apogee. Above main height.
949 <entry>dah dah</entry>
952 Descending. Below main height.
957 <entry>Landed</entry>
959 <entry>dit dah dit dit</entry>
962 Stable altitude for at least ten seconds.
967 <entry>Sensor error</entry>
969 <entry>dah dit dit dah</entry>
972 Error detected during sensor calibration.
981 In flight or “pad” mode, the altimeter engages the flight
982 state machine, goes into transmit-only mode to send telemetry,
983 and waits for launch to be detected. Flight mode is indicated
984 by an “di-dah-dah-dit” (“P” for pad) on the beeper or lights,
985 followed by beeps or flashes indicating the state of the
986 pyrotechnic igniter continuity. One beep/flash indicates
987 apogee continuity, two beeps/flashes indicate main continuity,
988 three beeps/flashes indicate both apogee and main continuity,
989 and one longer “brap” sound which is made by rapidly
990 alternating between two tones indicates no continuity. For a
991 dual deploy flight, make sure you're getting three beeps or
992 flashes before launching! For apogee-only or motor eject
993 flights, do what makes sense.
996 If idle mode is entered, you will hear an audible “di-dit” or
997 see two short flashes (“I” for idle), and the flight state
998 machine is disengaged, thus no ejection charges will fire.
999 The altimeters also listen for the radio link when in idle
1000 mode for requests sent via TeleDongle. Commands can be issued
1001 in idle mode over either USB or the radio link
1002 equivalently. TeleMini v1.0 only has the radio link. Idle
1003 mode is useful for configuring the altimeter, for extracting
1004 data from the on-board storage chip after flight, and for
1005 ground testing pyro charges.
1008 In “Idle” and “Pad” modes, once the mode indication
1009 beeps/flashes and continuity indication has been sent, if
1010 there is no space available to log the flight in on-board
1011 memory, the flight computer will emit a warbling tone (much
1012 slower than the “no continuity tone”)
1015 Here's a summary of all of the “pad” and “idle” mode indications.
1017 <title>Pad/Idle Indications</title>
1018 <?dbfo keep-together="always"?>
1019 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
1020 <colspec align='center' colwidth='*' colname='Name'/>
1021 <colspec align='center' colwidth='*' colname='Beeps'/>
1022 <colspec align='center' colwidth='*' colname='Description'/>
1026 <entry>Beeps</entry>
1027 <entry>Description</entry>
1032 <entry>Neither</entry>
1036 No continuity detected on either apogee or main
1042 <entry>Apogee</entry>
1046 Continuity detected only on apogee igniter.
1052 <entry>dit dit</entry>
1055 Continuity detected only on main igniter.
1061 <entry>dit dit dit</entry>
1064 Continuity detected on both igniters.
1069 <entry>Storage Full</entry>
1070 <entry>warble</entry>
1073 On-board data logging storage is full. This will
1074 not prevent the flight computer from safely
1075 controlling the flight or transmitting telemetry
1076 signals, but no record of the flight will be
1077 stored in on-board flash.
1086 Once landed, the flight computer will signal that by emitting
1087 the “Landed” sound described above, after which it will beep
1088 out the apogee height (in meters). Each digit is represented
1089 by a sequence of short “dit” beeps, with a pause between
1090 digits. A zero digit is represented with one long “dah”
1091 beep. The flight computer will continue to report landed mode
1092 and beep out the maximum height until turned off.
1095 One “neat trick” of particular value when TeleMetrum or TeleMega are used with
1096 very large air-frames, is that you can power the board up while the
1097 rocket is horizontal, such that it comes up in idle mode. Then you can
1098 raise the air-frame to launch position, and issue a 'reset' command
1099 via TeleDongle over the radio link to cause the altimeter to reboot and
1100 come up in flight mode. This is much safer than standing on the top
1101 step of a rickety step-ladder or hanging off the side of a launch
1102 tower with a screw-driver trying to turn on your avionics before
1103 installing igniters!
1106 TeleMini v1.0 is configured solely via the radio link. Of course, that
1107 means you need to know the TeleMini radio configuration values
1108 or you won't be able to communicate with it. For situations
1109 when you don't have the radio configuration values, TeleMini v1.0
1110 offers an 'emergency recovery' mode. In this mode, TeleMini is
1111 configured as follows:
1115 Sets the radio frequency to 434.550MHz
1120 Sets the radio calibration back to the factory value.
1125 Sets the callsign to N0CALL
1130 Does not go to 'pad' mode after five seconds.
1136 To get into 'emergency recovery' mode, first find the row of
1137 four small holes opposite the switch wiring. Using a short
1138 piece of small gauge wire, connect the outer two holes
1139 together, then power TeleMini up. Once the red LED is lit,
1140 disconnect the wire and the board should signal that it's in
1141 'idle' mode after the initial five second startup period.
1147 TeleMetrum and TeleMega include a complete GPS receiver. A
1148 complete explanation of how GPS works is beyond the scope of
1149 this manual, but the bottom line is that the GPS receiver
1150 needs to lock onto at least four satellites to obtain a solid
1151 3 dimensional position fix and know what time it is.
1154 The flight computers provide backup power to the GPS chip any time a
1155 battery is connected. This allows the receiver to “warm start” on
1156 the launch rail much faster than if every power-on were a GPS
1157 “cold start”. In typical operations, powering up
1158 on the flight line in idle mode while performing final air-frame
1159 preparation will be sufficient to allow the GPS receiver to cold
1160 start and acquire lock. Then the board can be powered down during
1161 RSO review and installation on a launch rod or rail. When the board
1162 is turned back on, the GPS system should lock very quickly, typically
1163 long before igniter installation and return to the flight line are
1168 <title>Controlling An Altimeter Over The Radio Link</title>
1170 One of the unique features of the Altus Metrum system is the
1171 ability to create a two way command link between TeleDongle
1172 and an altimeter using the digital radio transceivers
1173 built into each device. This allows you to interact with the
1174 altimeter from afar, as if it were directly connected to the
1178 Any operation which can be performed with a flight computer can
1179 either be done with the device directly connected to the
1180 computer via the USB cable, or through the radio
1181 link. TeleMini v1.0 doesn't provide a USB connector and so it is
1182 always communicated with over radio. Select the appropriate
1183 TeleDongle device when the list of devices is presented and
1184 AltosUI will interact with an altimeter over the radio link.
1187 One oddity in the current interface is how AltosUI selects the
1188 frequency for radio communications. Instead of providing
1189 an interface to specifically configure the frequency, it uses
1190 whatever frequency was most recently selected for the target
1191 TeleDongle device in Monitor Flight mode. If you haven't ever
1192 used that mode with the TeleDongle in question, select the
1193 Monitor Flight button from the top level UI, and pick the
1194 appropriate TeleDongle device. Once the flight monitoring
1195 window is open, select the desired frequency and then close it
1196 down again. All radio communications will now use that frequency.
1201 Save Flight Data—Recover flight data from the rocket without
1207 Configure altimeter apogee delays, main deploy heights
1208 and additional pyro event conditions
1209 to respond to changing launch conditions. You can also
1210 'reboot' the altimeter. Use this to remotely enable the
1211 flight computer by turning TeleMetrum or TeleMega on in “idle” mode,
1212 then once the air-frame is oriented for launch, you can
1213 reboot the altimeter and have it restart in pad mode
1214 without having to climb the scary ladder.
1219 Fire Igniters—Test your deployment charges without snaking
1220 wires out through holes in the air-frame. Simply assemble the
1221 rocket as if for flight with the apogee and main charges
1222 loaded, then remotely command the altimeter to fire the
1228 Operation over the radio link for configuring an altimeter, ground
1229 testing igniters, and so forth uses the same RF frequencies as flight
1230 telemetry. To configure the desired TeleDongle frequency, select
1231 the monitor flight tab, then use the frequency selector and
1232 close the window before performing other desired radio operations.
1235 The flight computers only enable radio commanding in 'idle' mode.
1236 TeleMetrum and TeleMega use the accelerometer to detect which orientation they
1237 start up in, so make sure you have the flight computer lying horizontally when you turn
1238 it on. Otherwise, it will start in 'pad' mode ready for
1239 flight, and will not be listening for command packets from TeleDongle.
1242 TeleMini listens for a command packet for five seconds after
1243 first being turned on, if it doesn't hear anything, it enters
1244 'pad' mode, ready for flight and will no longer listen for
1245 command packets. The easiest way to connect to TeleMini is to
1246 initiate the command and select the TeleDongle device. At this
1247 point, the TeleDongle will be attempting to communicate with
1248 the TeleMini. Now turn TeleMini on, and it should immediately
1249 start communicating with the TeleDongle and the desired
1250 operation can be performed.
1253 You can monitor the operation of the radio link by watching the
1254 lights on the devices. The red LED will flash each time a packet
1255 is transmitted, while the green LED will light up on TeleDongle when
1256 it is waiting to receive a packet from the altimeter.
1260 <title>Ground Testing </title>
1262 An important aspect of preparing a rocket using electronic deployment
1263 for flight is ground testing the recovery system. Thanks
1264 to the bi-directional radio link central to the Altus Metrum system,
1265 this can be accomplished in a TeleMega, TeleMetrum or TeleMini equipped rocket
1266 with less work than you may be accustomed to with other systems. It
1270 Just prep the rocket for flight, then power up the altimeter
1271 in “idle” mode (placing air-frame horizontal for TeleMetrum or TeleMega, or
1272 selecting the Configure Altimeter tab for TeleMini). This will cause
1273 the firmware to go into “idle” mode, in which the normal flight
1274 state machine is disabled and charges will not fire without
1275 manual command. You can now command the altimeter to fire the apogee
1276 or main charges from a safe distance using your computer and
1277 TeleDongle and the Fire Igniter tab to complete ejection testing.
1281 <title>Radio Link </title>
1283 Our flight computers all incorporate an RF transceiver, but
1284 it's not a full duplex system... each end can only be transmitting or
1285 receiving at any given moment. So we had to decide how to manage the
1289 By design, the altimeter firmware listens for the radio link when
1290 it's in “idle mode”, which
1291 allows us to use the radio link to configure the rocket, do things like
1292 ejection tests, and extract data after a flight without having to
1293 crack open the air-frame. However, when the board is in “flight
1294 mode”, the altimeter only
1295 transmits and doesn't listen at all. That's because we want to put
1296 ultimate priority on event detection and getting telemetry out of
1298 the radio in case the rocket crashes and we aren't able to extract
1302 We don't generally use a 'normal packet radio' mode like APRS
1303 because they're just too inefficient. The GFSK modulation we
1304 use is FSK with the base-band pulses passed through a Gaussian
1305 filter before they go into the modulator to limit the
1306 transmitted bandwidth. When combined with forward error
1307 correction and interleaving, this allows us to have a very
1308 robust 19.2 kilobit data link with only 10-40 milliwatts of
1309 transmit power, a whip antenna in the rocket, and a hand-held
1310 Yagi on the ground. We've had flights to above 21k feet AGL
1311 with great reception, and calculations suggest we should be
1312 good to well over 40k feet AGL with a 5-element yagi on the
1313 ground with our 10mW units and over 100k feet AGL with the
1314 40mW devices. We hope to fly boards to higher altitudes over
1315 time, and would of course appreciate customer feedback on
1316 performance in higher altitude flights!
1319 TeleMetrum v2.0 and TeleMega can send APRS if desired, and the
1320 interval between APRS packets can be configured. As each APRS
1321 packet takes a full second to transmit, we recommend an
1322 interval of at least 5 seconds to avoid consuming too much
1323 battery power or radio channel bandwidth.
1327 <title>Configurable Parameters</title>
1329 Configuring an Altus Metrum altimeter for flight is very
1330 simple. Even on our baro-only TeleMini and EasyMini boards, the use of a Kalman
1331 filter means there is no need to set a “mach delay”. The few
1332 configurable parameters can all be set using AltosUI over USB or
1333 or radio link via TeleDongle.
1336 <title>Radio Frequency</title>
1338 Altus Metrum boards support radio frequencies in the 70cm
1339 band. By default, the configuration interface provides a
1340 list of 10 “standard” frequencies in 100kHz channels starting at
1341 434.550MHz. However, the firmware supports use of
1342 any 50kHz multiple within the 70cm band. At any given
1343 launch, we highly recommend coordinating when and by whom each
1344 frequency will be used to avoid interference. And of course, both
1345 altimeter and TeleDongle must be configured to the same
1346 frequency to successfully communicate with each other.
1350 <title>Apogee Delay</title>
1352 Apogee delay is the number of seconds after the altimeter detects flight
1353 apogee that the drogue charge should be fired. In most cases, this
1354 should be left at the default of 0. However, if you are flying
1355 redundant electronics such as for an L3 certification, you may wish
1356 to set one of your altimeters to a positive delay so that both
1357 primary and backup pyrotechnic charges do not fire simultaneously.
1360 The Altus Metrum apogee detection algorithm fires exactly at
1361 apogee. If you are also flying an altimeter like the
1362 PerfectFlite MAWD, which only supports selecting 0 or 1
1363 seconds of apogee delay, you may wish to set the MAWD to 0
1364 seconds delay and set the TeleMetrum to fire your backup 2
1365 or 3 seconds later to avoid any chance of both charges
1366 firing simultaneously. We've flown several air-frames this
1367 way quite happily, including Keith's successful L3 cert.
1371 <title>Main Deployment Altitude</title>
1373 By default, the altimeter will fire the main deployment charge at an
1374 elevation of 250 meters (about 820 feet) above ground. We think this
1375 is a good elevation for most air-frames, but feel free to change this
1376 to suit. In particular, if you are flying two altimeters, you may
1378 deployment elevation for the backup altimeter to be something lower
1379 than the primary so that both pyrotechnic charges don't fire
1384 <title>Maximum Flight Log</title>
1386 Changing this value will set the maximum amount of flight
1387 log storage that an individual flight will use. The
1388 available storage is divided into as many flights of the
1389 specified size as can fit in the available space. You can
1390 download and erase individual flight logs. If you fill up
1391 the available storage, future flights will not get logged
1392 until you erase some of the stored ones.
1395 Even though our flight computers (except TeleMini v1.0) can store
1396 multiple flights, we strongly recommend downloading and saving
1397 flight data after each flight.
1401 <title>Ignite Mode</title>
1403 Instead of firing one charge at apogee and another charge at
1404 a fixed height above the ground, you can configure the
1405 altimeter to fire both at apogee or both during
1406 descent. This was added to support an airframe Bdale designed that
1407 had two altimeters, one in the fin can and one in the nose.
1410 Providing the ability to use both igniters for apogee or
1411 main allows some level of redundancy without needing two
1412 flight computers. In Redundant Apogee or Redundant Main
1413 mode, the two charges will be fired two seconds apart.
1417 <title>Pad Orientation</title>
1419 TeleMetrum and TeleMega measure acceleration along the axis
1420 of the board. Which way the board is oriented affects the
1421 sign of the acceleration value. Instead of trying to guess
1422 which way the board is mounted in the air frame, the
1423 altimeter must be explicitly configured for either Antenna
1424 Up or Antenna Down. The default, Antenna Up, expects the end
1425 of the board connected to the 70cm antenna to be nearest the
1426 nose of the rocket, with the end containing the screw
1427 terminals nearest the tail.
1431 <title>Configurable Pyro Channels</title>
1433 In addition to the usual Apogee and Main pyro channels,
1434 TeleMega has four additional channels that can be configured
1435 to activate when various flight conditions are
1436 satisfied. You can select as many conditions as necessary;
1437 all of them must be met in order to activate the
1438 channel. The conditions available are:
1443 Acceleration away from the ground. Select a value, and
1444 then choose whether acceleration should be above or
1445 below that value. Acceleration is positive upwards, so
1446 accelerating towards the ground would produce negative
1447 numbers. Acceleration during descent is noisy and
1448 inaccurate, so be careful when using it during these
1449 phases of the flight.
1454 Vertical speed. Select a value, and then choose whether
1455 vertical speed should be above or below that
1456 value. Speed is positive upwards, so moving towards the
1457 ground would produce negative numbers. Speed during
1458 descent is a bit noisy and so be careful when using it
1459 during these phases of the flight.
1464 Height. Select a value, and then choose whether the
1465 height above the launch pad should be above or below
1471 Orientation. TeleMega contains a 3-axis gyroscope and
1472 accelerometer which is used to measure the current
1473 angle. Note that this angle is not the change in angle
1474 from the launch pad, but rather absolute relative to
1475 gravity; the 3-axis accelerometer is used to compute the
1476 angle of the rocket on the launch pad and initialize the
1477 system. Because this value is computed by integrating
1478 rate gyros, it gets progressively less accurate as the
1479 flight goes on. It should have an accumulated error of
1480 less than 0.2°/second (after 10 seconds of flight, the
1481 error should be less than 2°).
1484 The usual use of the orientation configuration is to
1485 ensure that the rocket is traveling mostly upwards when
1486 deciding whether to ignite air starts or additional
1487 stages. For that, choose a reasonable maximum angle
1488 (like 20°) and set the motor igniter to require an angle
1489 of less than that value.
1494 Flight Time. Time since boost was detected. Select a
1495 value and choose whether to activate the pyro channel
1496 before or after that amount of time.
1501 Ascending. A simple test saying whether the rocket is
1502 going up or not. This is exactly equivalent to testing
1503 whether the speed is > 0.
1508 Descending. A simple test saying whether the rocket is
1509 going down or not. This is exactly equivalent to testing
1510 whether the speed is < 0.
1515 After Motor. The flight software counts each time the
1516 rocket starts accelerating (presumably due to a motor or
1517 motors igniting). Use this value to count ignitions for
1518 multi-staged or multi-airstart launches.
1523 Delay. This value doesn't perform any checks, instead it
1524 inserts a delay between the time when the other
1525 parameters become true and when the pyro channel is
1531 Flight State. The flight software tracks the flight
1532 through a sequence of states:
1536 Boost. The motor has lit and the rocket is
1537 accelerating upwards.
1542 Fast. The motor has burned out and the rocket is
1543 descellerating, but it is going faster than 200m/s.
1548 Coast. The rocket is still moving upwards and
1549 decelerating, but the speed is less than 200m/s.
1554 Drogue. The rocket has reached apogee and is heading
1555 back down, but is above the configured Main
1561 Main. The rocket is still descending, and is below
1567 Landed. The rocket is no longer moving.
1573 You can select a state to limit when the pyro channel
1574 may activate; note that the check is based on when the
1575 rocket transitions <emphasis>into</emphasis> the state, and so checking for
1576 “greater than Boost” means that the rocket is currently
1577 in boost or some later state.
1580 When a motor burns out, the rocket enters either Fast or
1581 Coast state (depending on how fast it is moving). If the
1582 computer detects upwards acceleration again, it will
1583 move back to Boost state.
1592 <title>AltosUI</title>
1596 <imagedata fileref="altosui.png" width="4.6in"/>
1601 The AltosUI program provides a graphical user interface for
1602 interacting with the Altus Metrum product family. AltosUI can
1603 monitor telemetry data, configure devices and many other
1604 tasks. The primary interface window provides a selection of
1605 buttons, one for each major activity in the system. This chapter
1606 is split into sections, each of which documents one of the tasks
1607 provided from the top-level toolbar.
1610 <title>Monitor Flight</title>
1611 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
1613 Selecting this item brings up a dialog box listing all of the
1614 connected TeleDongle devices. When you choose one of these,
1615 AltosUI will create a window to display telemetry data as
1616 received by the selected TeleDongle device.
1621 <imagedata fileref="device-selection.png" width="3.1in"/>
1626 All telemetry data received are automatically recorded in
1627 suitable log files. The name of the files includes the current
1628 date and rocket serial and flight numbers.
1631 The radio frequency being monitored by the TeleDongle device is
1632 displayed at the top of the window. You can configure the
1633 frequency by clicking on the frequency box and selecting the desired
1634 frequency. AltosUI remembers the last frequency selected for each
1635 TeleDongle and selects that automatically the next time you use
1639 Below the TeleDongle frequency selector, the window contains a few
1640 significant pieces of information about the altimeter providing
1641 the telemetry data stream:
1645 <para>The configured call-sign</para>
1648 <para>The device serial number</para>
1651 <para>The flight number. Each altimeter remembers how many
1657 The rocket flight state. Each flight passes through several
1658 states including Pad, Boost, Fast, Coast, Drogue, Main and
1664 The Received Signal Strength Indicator value. This lets
1665 you know how strong a signal TeleDongle is receiving. The
1666 radio inside TeleDongle operates down to about -99dBm;
1667 weaker signals may not be receivable. The packet link uses
1668 error detection and correction techniques which prevent
1669 incorrect data from being reported.
1674 The age of the displayed data, in seconds since the last
1675 successfully received telemetry packet. In normal operation
1676 this will stay in the low single digits. If the number starts
1677 counting up, then you are no longer receiving data over the radio
1678 link from the flight computer.
1683 Finally, the largest portion of the window contains a set of
1684 tabs, each of which contain some information about the rocket.
1685 They're arranged in 'flight order' so that as the flight
1686 progresses, the selected tab automatically switches to display
1687 data relevant to the current state of the flight. You can select
1688 other tabs at any time. The final 'table' tab displays all of
1689 the raw telemetry values in one place in a spreadsheet-like format.
1692 <title>Launch Pad</title>
1696 <imagedata fileref="launch-pad.png" width="5.5in"/>
1701 The 'Launch Pad' tab shows information used to decide when the
1702 rocket is ready for flight. The first elements include red/green
1703 indicators, if any of these is red, you'll want to evaluate
1704 whether the rocket is ready to launch:
1707 <term>Battery Voltage</term>
1710 This indicates whether the Li-Po battery powering the
1711 flight computer has sufficient charge to last for
1712 the duration of the flight. A value of more than
1713 3.8V is required for a 'GO' status.
1718 <term>Apogee Igniter Voltage</term>
1721 This indicates whether the apogee
1722 igniter has continuity. If the igniter has a low
1723 resistance, then the voltage measured here will be close
1724 to the Li-Po battery voltage. A value greater than 3.2V is
1725 required for a 'GO' status.
1730 <term>Main Igniter Voltage</term>
1733 This indicates whether the main
1734 igniter has continuity. If the igniter has a low
1735 resistance, then the voltage measured here will be close
1736 to the Li-Po battery voltage. A value greater than 3.2V is
1737 required for a 'GO' status.
1742 <term>On-board Data Logging</term>
1745 This indicates whether there is
1746 space remaining on-board to store flight data for the
1747 upcoming flight. If you've downloaded data, but failed
1748 to erase flights, there may not be any space
1749 left. Most of our flight computers can store multiple
1750 flights, depending on the configured maximum flight log
1751 size. TeleMini v1.0 stores only a single flight, so it
1753 downloaded and erased after each flight to capture
1754 data. This only affects on-board flight logging; the
1755 altimeter will still transmit telemetry and fire
1756 ejection charges at the proper times even if the flight
1757 data storage is full.
1762 <term>GPS Locked</term>
1765 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
1766 currently able to compute position information. GPS requires
1767 at least 4 satellites to compute an accurate position.
1772 <term>GPS Ready</term>
1775 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
1776 10 consecutive positions without losing lock. This ensures
1777 that the GPS receiver has reliable reception from the
1785 The Launchpad tab also shows the computed launch pad position
1786 and altitude, averaging many reported positions to improve the
1787 accuracy of the fix.
1791 <title>Ascent</title>
1795 <imagedata fileref="ascent.png" width="5.5in"/>
1800 This tab is shown during Boost, Fast and Coast
1801 phases. The information displayed here helps monitor the
1802 rocket as it heads towards apogee.
1805 The height, speed, acceleration and tilt are shown along
1806 with the maximum values for each of them. This allows you to
1807 quickly answer the most commonly asked questions you'll hear
1811 The current latitude and longitude reported by the GPS are
1812 also shown. Note that under high acceleration, these values
1813 may not get updated as the GPS receiver loses position
1814 fix. Once the rocket starts coasting, the receiver should
1815 start reporting position again.
1818 Finally, the current igniter voltages are reported as in the
1819 Launch Pad tab. This can help diagnose deployment failures
1820 caused by wiring which comes loose under high acceleration.
1824 <title>Descent</title>
1828 <imagedata fileref="descent.png" width="5.5in"/>
1833 Once the rocket has reached apogee and (we hope) activated the
1834 apogee charge, attention switches to tracking the rocket on
1835 the way back to the ground, and for dual-deploy flights,
1836 waiting for the main charge to fire.
1839 To monitor whether the apogee charge operated correctly, the
1840 current descent rate is reported along with the current
1841 height. Good descent rates vary based on the choice of recovery
1842 components, but generally range from 15-30m/s on drogue and should
1843 be below 10m/s when under the main parachute in a dual-deploy flight.
1846 With GPS-equipped flight computers, you can locate the rocket in the
1847 sky using the elevation and bearing information to figure
1848 out where to look. Elevation is in degrees above the
1849 horizon. Bearing is reported in degrees relative to true
1850 north. Range can help figure out how big the rocket will
1851 appear. Ground Distance shows how far it is to a point
1852 directly under the rocket and can help figure out where the
1853 rocket is likely to land. Note that all of these values are
1854 relative to the pad location. If the elevation is near 90°,
1855 the rocket is over the pad, not over you.
1858 Finally, the igniter voltages are reported in this tab as
1859 well, both to monitor the main charge as well as to see what
1860 the status of the apogee charge is. Note that some commercial
1861 e-matches are designed to retain continuity even after being
1862 fired, and will continue to show as green or return from red to
1867 <title>Landed</title>
1871 <imagedata fileref="landed.png" width="5.5in"/>
1876 Once the rocket is on the ground, attention switches to
1877 recovery. While the radio signal is often lost once the
1878 rocket is on the ground, the last reported GPS position is
1879 generally within a short distance of the actual landing location.
1882 The last reported GPS position is reported both by
1883 latitude and longitude as well as a bearing and distance from
1884 the launch pad. The distance should give you a good idea of
1885 whether to walk or hitch a ride. Take the reported
1886 latitude and longitude and enter them into your hand-held GPS
1887 unit and have that compute a track to the landing location.
1890 Our flight computers will continue to transmit RDF
1891 tones after landing, allowing you to locate the rocket by
1892 following the radio signal if necessary. You may need to get
1893 away from the clutter of the flight line, or even get up on
1894 a hill (or your neighbor's RV roof) to receive the RDF signal.
1897 The maximum height, speed and acceleration reported
1898 during the flight are displayed for your admiring observers.
1899 The accuracy of these immediate values depends on the quality
1900 of your radio link and how many packets were received.
1901 Recovering the on-board data after flight may yield
1902 more precise results.
1905 To get more detailed information about the flight, you can
1906 click on the 'Graph Flight' button which will bring up a
1907 graph window for the current flight.
1911 <title>Table</title>
1915 <imagedata fileref="table.png" width="5.5in"/>
1920 The table view shows all of the data available from the
1921 flight computer. Probably the most useful data on
1922 this tab is the detailed GPS information, which includes
1923 horizontal dilution of precision information, and
1924 information about the signal being received from the satellites.
1928 <title>Site Map</title>
1932 <imagedata fileref="site-map.png" width="5.5in"/>
1937 When the TeleMetrum has a GPS fix, the Site Map tab will map
1938 the rocket's position to make it easier for you to locate the
1939 rocket, both while it is in the air, and when it has landed. The
1940 rocket's state is indicated by color: white for pad, red for
1941 boost, pink for fast, yellow for coast, light blue for drogue,
1942 dark blue for main, and black for landed.
1945 The map's scale is approximately 3m (10ft) per pixel. The map
1946 can be dragged using the left mouse button. The map will attempt
1947 to keep the rocket roughly centered while data is being received.
1950 Images are fetched automatically via the Google Maps Static API,
1951 and cached on disk for reuse. If map images cannot be downloaded,
1952 the rocket's path will be traced on a dark gray background
1956 You can pre-load images for your favorite launch sites
1957 before you leave home; check out the 'Preload Maps' section below.
1962 <title>Save Flight Data</title>
1964 The altimeter records flight data to its internal flash memory.
1965 TeleMetrum data is recorded at a much higher rate than the telemetry
1966 system can handle, and is not subject to radio drop-outs. As
1967 such, it provides a more complete and precise record of the
1968 flight. The 'Save Flight Data' button allows you to read the
1969 flash memory and write it to disk.
1972 Clicking on the 'Save Flight Data' button brings up a list of
1973 connected flight computers and TeleDongle devices. If you select a
1974 flight computer, the flight data will be downloaded from that
1975 device directly. If you select a TeleDongle device, flight data
1976 will be downloaded from a flight computer over radio link via the
1977 specified TeleDongle. See the chapter on Controlling An Altimeter
1978 Over The Radio Link for more information.
1981 After the device has been selected, a dialog showing the
1982 flight data saved in the device will be shown allowing you to
1983 select which flights to download and which to delete. With
1984 version 0.9 or newer firmware, you must erase flights in order
1985 for the space they consume to be reused by another
1986 flight. This prevents accidentally losing flight data
1987 if you neglect to download data before flying again. Note that
1988 if there is no more space available in the device, then no
1989 data will be recorded during the next flight.
1992 The file name for each flight log is computed automatically
1993 from the recorded flight date, altimeter serial number and
1994 flight number information.
1998 <title>Replay Flight</title>
2000 Select this button and you are prompted to select a flight
2001 record file, either a .telem file recording telemetry data or a
2002 .eeprom file containing flight data saved from the altimeter
2006 Once a flight record is selected, the flight monitor interface
2007 is displayed and the flight is re-enacted in real time. Check
2008 the Monitor Flight chapter above to learn how this window operates.
2012 <title>Graph Data</title>
2014 Select this button and you are prompted to select a flight
2015 record file, either a .telem file recording telemetry data or a
2016 .eeprom file containing flight data saved from
2020 Note that telemetry files will generally produce poor graphs
2021 due to the lower sampling rate and missed telemetry packets.
2022 Use saved flight data in .eeprom files for graphing where possible.
2025 Once a flight record is selected, a window with multiple tabs is
2029 <title>Flight Graph</title>
2033 <imagedata fileref="graph.png" width="6in" scalefit="1"/>
2038 By default, the graph contains acceleration (blue),
2039 velocity (green) and altitude (red).
2042 The graph can be zoomed into a particular area by clicking and
2043 dragging down and to the right. Once zoomed, the graph can be
2044 reset by clicking and dragging up and to the left. Holding down
2045 control and clicking and dragging allows the graph to be panned.
2046 The right mouse button causes a pop-up menu to be displayed, giving
2047 you the option save or print the plot.
2051 <title>Configure Graph</title>
2055 <imagedata fileref="graph-configure.png" width="6in" scalefit="1"/>
2060 This selects which graph elements to show, and, at the
2061 very bottom, lets you switch between metric and
2066 <title>Flight Statistics</title>
2070 <imagedata fileref="graph-stats.png" width="6in" scalefit="1"/>
2075 Shows overall data computed from the flight.
2083 <imagedata fileref="graph-map.png" width="6in" scalefit="1"/>
2088 Shows a satellite image of the flight area overlaid
2089 with the path of the flight. The red concentric
2090 circles mark the launch pad, the black concentric
2091 circles mark the landing location.
2096 <title>Export Data</title>
2098 This tool takes the raw data files and makes them available for
2099 external analysis. When you select this button, you are prompted to
2100 select a flight data file, which can be either a .eeprom or .telem.
2101 The .eeprom files contain higher resolution and more continuous data,
2102 while .telem files contain receiver signal strength information.
2103 Next, a second dialog appears which is used to select
2104 where to write the resulting file. It has a selector to choose
2105 between CSV and KML file formats.
2108 <title>Comma Separated Value Format</title>
2110 This is a text file containing the data in a form suitable for
2111 import into a spreadsheet or other external data analysis
2112 tool. The first few lines of the file contain the version and
2113 configuration information from the altimeter, then
2114 there is a single header line which labels all of the
2115 fields. All of these lines start with a '#' character which
2116 many tools can be configured to skip over.
2119 The remaining lines of the file contain the data, with each
2120 field separated by a comma and at least one space. All of
2121 the sensor values are converted to standard units, with the
2122 barometric data reported in both pressure, altitude and
2123 height above pad units.
2127 <title>Keyhole Markup Language (for Google Earth)</title>
2129 This is the format used by Google Earth to provide an overlay
2130 within that application. With this, you can use Google Earth to
2131 see the whole flight path in 3D.
2136 <title>Configure Altimeter</title>
2140 <imagedata fileref="configure-altimeter.png" width="3.6in" scalefit="1"/>
2145 Select this button and then select either an altimeter or
2146 TeleDongle Device from the list provided. Selecting a TeleDongle
2147 device will use the radio link to configure a remote altimeter.
2150 The first few lines of the dialog provide information about the
2151 connected device, including the product name,
2152 software version and hardware serial number. Below that are the
2153 individual configuration entries.
2156 At the bottom of the dialog, there are four buttons:
2163 This writes any changes to the
2164 configuration parameter block in flash memory. If you don't
2165 press this button, any changes you make will be lost.
2173 This resets the dialog to the most recently saved values,
2174 erasing any changes you have made.
2182 This reboots the device. Use this to
2183 switch from idle to pad mode by rebooting once the rocket is
2184 oriented for flight, or to confirm changes you think you saved
2193 This closes the dialog. Any unsaved changes will be
2200 The rest of the dialog contains the parameters to be configured.
2203 <title>Main Deploy Altitude</title>
2205 This sets the altitude (above the recorded pad altitude) at
2206 which the 'main' igniter will fire. The drop-down menu shows
2207 some common values, but you can edit the text directly and
2208 choose whatever you like. If the apogee charge fires below
2209 this altitude, then the main charge will fire two seconds
2210 after the apogee charge fires.
2214 <title>Apogee Delay</title>
2216 When flying redundant electronics, it's often important to
2217 ensure that multiple apogee charges don't fire at precisely
2218 the same time, as that can over pressurize the apogee deployment
2219 bay and cause a structural failure of the air-frame. The Apogee
2220 Delay parameter tells the flight computer to fire the apogee
2221 charge a certain number of seconds after apogee has been
2226 <title>Radio Frequency</title>
2228 This configures which of the frequencies to use for both
2229 telemetry and packet command mode. Note that if you set this
2230 value via packet command mode, the TeleDongle frequency will
2231 also be automatically reconfigured to match so that
2232 communication will continue afterwards.
2236 <title>RF Calibration</title>
2238 The radios in every Altus Metrum device are calibrated at the
2239 factory to ensure that they transmit and receive on the
2240 specified frequency. If you need to you can adjust the calibration
2241 by changing this value. Do not do this without understanding what
2242 the value means, read the appendix on calibration and/or the source
2243 code for more information. To change a TeleDongle's calibration,
2244 you must reprogram the unit completely.
2248 <title>Telemetry/RDF/APRS Enable</title>
2250 Enables the radio for transmission during flight. When
2251 disabled, the radio will not transmit anything during flight
2256 <title>APRS Interval</title>
2258 How often to transmit GPS information via APRS. This option
2259 is available on TeleMetrum v2 and TeleMega
2260 boards. TeleMetrum v1 boards cannot transmit APRS
2261 packets. Note that a single APRS packet takes nearly a full
2262 second to transmit, so enabling this option will prevent
2263 sending any other telemetry during that time.
2267 <title>Callsign</title>
2269 This sets the call sign included in each telemetry packet. Set this
2270 as needed to conform to your local radio regulations.
2274 <title>Maximum Flight Log Size</title>
2276 This sets the space (in kilobytes) allocated for each flight
2277 log. The available space will be divided into chunks of this
2278 size. A smaller value will allow more flights to be stored,
2279 a larger value will record data from longer flights.
2283 <title>Ignite Mode</title>
2285 TeleMetrum and TeleMini provide two igniter channels as they
2286 were originally designed as dual-deploy flight
2287 computers. This configuration parameter allows the two
2288 channels to be used in different configurations.
2292 <term>Dual Deploy</term>
2295 This is the usual mode of operation; the
2296 'apogee' channel is fired at apogee and the 'main'
2297 channel at the height above ground specified by the
2298 'Main Deploy Altitude' during descent.
2303 <term>Redundant Apogee</term>
2306 This fires both channels at
2307 apogee, the 'apogee' channel first followed after a two second
2308 delay by the 'main' channel.
2313 <term>Redundant Main</term>
2316 This fires both channels at the
2317 height above ground specified by the Main Deploy
2318 Altitude setting during descent. The 'apogee'
2319 channel is fired first, followed after a two second
2320 delay by the 'main' channel.
2327 <title>Pad Orientation</title>
2329 Because they include accelerometers, TeleMetrum and
2330 TeleMega are sensitive to the orientation of the board. By
2331 default, they expect the antenna end to point forward. This
2332 parameter allows that default to be changed, permitting the
2333 board to be mounted with the antenna pointing aft instead.
2337 <term>Antenna Up</term>
2340 In this mode, the antenna end of the
2341 flight computer must point forward, in line with the
2342 expected flight path.
2347 <term>Antenna Down</term>
2350 In this mode, the antenna end of the
2351 flight computer must point aft, in line with the
2352 expected flight path.
2359 <title>Configure Pyro Channels</title>
2363 <imagedata fileref="configure-pyro.png" width="6in" scalefit="1"/>
2368 This opens a separate window to configure the additional
2369 pyro channels available on TeleMega. One column is
2370 presented for each channel. Each row represents a single
2371 parameter, if enabled the parameter must meet the specified
2372 test for the pyro channel to be fired. See the Pyro Channels
2373 section in the System Operation chapter above for a
2374 description of these parameters.
2377 Select conditions and set the related value; the pyro
2378 channel will be activated when <emphasis>all</emphasis> of the
2379 conditions are met. Each pyro channel has a separate set of
2380 configuration values, so you can use different values for
2381 the same condition with different channels.
2384 Once you have selected the appropriate configuration for all
2385 of the necessary pyro channels, you can save the pyro
2386 configuration along with the rest of the flight computer
2387 configuration by pressing the 'Save' button in the main
2388 Configure Flight Computer window.
2393 <title>Configure AltosUI</title>
2397 <imagedata fileref="configure-altosui.png" width="2.4in" scalefit="1"/>
2402 This button presents a dialog so that you can configure the AltosUI global settings.
2405 <title>Voice Settings</title>
2407 AltosUI provides voice announcements during flight so that you
2408 can keep your eyes on the sky and still get information about
2409 the current flight status. However, sometimes you don't want
2416 <para>Turns all voice announcements on and off</para>
2420 <term>Test Voice</term>
2423 Plays a short message allowing you to verify
2424 that the audio system is working and the volume settings
2432 <title>Log Directory</title>
2434 AltosUI logs all telemetry data and saves all TeleMetrum flash
2435 data to this directory. This directory is also used as the
2436 staring point when selecting data files for display or export.
2439 Click on the directory name to bring up a directory choosing
2440 dialog, select a new directory and click 'Select Directory' to
2441 change where AltosUI reads and writes data files.
2445 <title>Callsign</title>
2447 This value is transmitted in each command packet sent from
2448 TeleDongle and received from an altimeter. It is not used in
2449 telemetry mode, as the callsign configured in the altimeter board
2450 is included in all telemetry packets. Configure this
2451 with the AltosUI operators call sign as needed to comply with
2452 your local radio regulations.
2455 Note that to successfully command a flight computer over the radio
2456 (to configure the altimeter, monitor idle, or fire pyro charges),
2457 the callsign configured here must exactly match the callsign
2458 configured in the flight computer. This matching is case
2463 <title>Imperial Units</title>
2465 This switches between metric units (meters) and imperial
2466 units (feet and miles). This affects the display of values
2467 use during flight monitoring, configuration, data graphing
2468 and all of the voice announcements. It does not change the
2469 units used when exporting to CSV files, those are always
2470 produced in metric units.
2474 <title>Font Size</title>
2476 Selects the set of fonts used in the flight monitor
2477 window. Choose between the small, medium and large sets.
2481 <title>Serial Debug</title>
2483 This causes all communication with a connected device to be
2484 dumped to the console from which AltosUI was started. If
2485 you've started it from an icon or menu entry, the output
2486 will simply be discarded. This mode can be useful to debug
2487 various serial communication issues.
2491 <title>Manage Frequencies</title>
2493 This brings up a dialog where you can configure the set of
2494 frequencies shown in the various frequency menus. You can
2495 add as many as you like, or even reconfigure the default
2496 set. Changing this list does not affect the frequency
2497 settings of any devices, it only changes the set of
2498 frequencies shown in the menus.
2503 <title>Configure Groundstation</title>
2507 <imagedata fileref="configure-groundstation.png" width="3.1in" scalefit="1"/>
2512 Select this button and then select a TeleDongle Device from the list provided.
2515 The first few lines of the dialog provide information about the
2516 connected device, including the product name,
2517 software version and hardware serial number. Below that are the
2518 individual configuration entries.
2521 Note that the TeleDongle itself doesn't save any configuration
2522 data, the settings here are recorded on the local machine in
2523 the Java preferences database. Moving the TeleDongle to
2524 another machine, or using a different user account on the same
2525 machine will cause settings made here to have no effect.
2528 At the bottom of the dialog, there are three buttons:
2535 This writes any changes to the
2536 local Java preferences file. If you don't
2537 press this button, any changes you make will be lost.
2545 This resets the dialog to the most recently saved values,
2546 erasing any changes you have made.
2554 This closes the dialog. Any unsaved changes will be
2561 The rest of the dialog contains the parameters to be configured.
2564 <title>Frequency</title>
2566 This configures the frequency to use for both telemetry and
2567 packet command mode. Set this before starting any operation
2568 involving packet command mode so that it will use the right
2569 frequency. Telemetry monitoring mode also provides a menu to
2570 change the frequency, and that menu also sets the same Java
2571 preference value used here.
2575 <title>Radio Calibration</title>
2577 The radios in every Altus Metrum device are calibrated at the
2578 factory to ensure that they transmit and receive on the
2579 specified frequency. To change a TeleDongle's calibration,
2580 you must reprogram the unit completely, so this entry simply
2581 shows the current value and doesn't allow any changes.
2586 <title>Flash Image</title>
2588 This reprograms Altus Metrum devices with new
2589 firmware. TeleMetrum v1.x, TeleDongle, TeleMini and TeleBT are
2590 all reprogrammed by using another similar unit as a
2591 programming dongle (pair programming). TeleMega, TeleMetrum v2
2592 and EasyMini are all programmed directly over their USB ports
2593 (self programming). Please read the directions for flashing
2594 devices in the Updating Device Firmware chapter below.
2598 <title>Fire Igniter</title>
2602 <imagedata fileref="fire-igniter.png" width="1.2in" scalefit="1"/>
2607 This activates the igniter circuits in the flight computer to help
2608 test recovery systems deployment. Because this command can operate
2609 over the Packet Command Link, you can prepare the rocket as
2610 for flight and then test the recovery system without needing
2611 to snake wires inside the air-frame.
2614 Selecting the 'Fire Igniter' button brings up the usual device
2615 selection dialog. Pick the desired device. This brings up another
2616 window which shows the current continuity test status for all
2617 of the pyro channels.
2620 Next, select the desired igniter to fire. This will enable the
2624 Select the 'Arm' button. This enables the 'Fire' button. The
2625 word 'Arm' is replaced by a countdown timer indicating that
2626 you have 10 seconds to press the 'Fire' button or the system
2627 will deactivate, at which point you start over again at
2628 selecting the desired igniter.
2632 <title>Scan Channels</title>
2636 <imagedata fileref="scan-channels.png" width="3.2in" scalefit="1"/>
2641 This listens for telemetry packets on all of the configured
2642 frequencies, displaying information about each device it
2643 receives a packet from. You can select which of the three
2644 telemetry formats should be tried; by default, it only listens
2645 for the standard telemetry packets used in v1.0 and later
2650 <title>Load Maps</title>
2654 <imagedata fileref="load-maps.png" width="5.2in" scalefit="1"/>
2659 Before heading out to a new launch site, you can use this to
2660 load satellite images in case you don't have internet
2661 connectivity at the site. This loads a fairly large area
2662 around the launch site, which should cover any flight you're likely to make.
2665 There's a drop-down menu of launch sites we know about; if
2666 your favorites aren't there, please let us know the lat/lon
2667 and name of the site. The contents of this list are actually
2668 downloaded from our server at run-time, so as new sites are sent
2669 in, they'll get automatically added to this list.
2672 If the launch site isn't in the list, you can manually enter the lat/lon values
2675 Clicking the 'Load Map' button will fetch images from Google
2676 Maps; note that Google limits how many images you can fetch at
2677 once, so if you load more than one launch site, you may get
2678 some gray areas in the map which indicate that Google is tired
2679 of sending data to you. Try again later.
2683 <title>Monitor Idle</title>
2685 This brings up a dialog similar to the Monitor Flight UI,
2686 except it works with the altimeter in “idle” mode by sending
2687 query commands to discover the current state rather than
2688 listening for telemetry packets. Because this uses command
2689 mode, it needs to have the TeleDongle and flight computer
2690 callsigns match exactly. If you can receive telemetry, but
2691 cannot manage to run Monitor Idle, then it's very likely that
2692 your callsigns are different in some way.
2697 <title>AltosDroid</title>
2699 AltosDroid provides the same flight monitoring capabilities as
2700 AltosUI, but runs on Android devices and is designed to connect
2701 to a TeleBT receiver over Bluetooth™. AltosDroid monitors
2702 telemetry data, logging it to internal storage in the Android
2703 device, and presents that data in a UI the same way the 'Monitor
2704 Flight' window does in AltosUI.
2707 This manual will explain how to configure AltosDroid, connect
2708 to TeleBT, operate the flight monitoring interface and describe
2709 what the displayed data means.
2712 <title>Installing AltosDroid</title>
2714 AltosDroid is available from the Google Play store. To install
2715 it on your Android device, open the Google Play Store
2716 application and search for “altosdroid”. Make sure you don't
2717 have a space between “altos” and “droid” or you probably won't
2718 find what you want. That should bring you to the right page
2719 from which you can download and install the application.
2723 <title>Connecting to TeleBT</title>
2725 Press the Android 'Menu' button or soft-key to see the
2726 configuration options available. Select the 'Connect a device'
2727 option and then the 'Scan for devices' entry at the bottom to
2728 look for your TeleBT device. Select your device, and when it
2729 asks for the code, enter '1234'.
2732 Subsequent connections will not require you to enter that
2733 code, and your 'paired' device will appear in the list without
2738 <title>Configuring AltosDroid</title>
2740 The only configuration option available for AltosDroid is
2741 which frequency to listen on. Press the Android 'Menu' button
2742 or soft-key and pick the 'Select radio frequency' entry. That
2743 brings up a menu of pre-set radio frequencies; pick the one
2744 which matches your altimeter.
2748 <title>AltosDroid Flight Monitoring</title>
2750 AltosDroid is designed to mimic the AltosUI flight monitoring
2751 display, providing separate tabs for each stage of your rocket
2752 flight along with a tab containing a map of the local area
2753 with icons marking the current location of the altimeter and
2759 The 'Launch Pad' tab shows information used to decide when the
2760 rocket is ready for flight. The first elements include red/green
2761 indicators, if any of these is red, you'll want to evaluate
2762 whether the rocket is ready to launch:
2765 <term>Battery Voltage</term>
2768 This indicates whether the Li-Po battery
2769 powering the TeleMetrum has sufficient charge to last for
2770 the duration of the flight. A value of more than
2771 3.8V is required for a 'GO' status.
2776 <term>Apogee Igniter Voltage</term>
2779 This indicates whether the apogee
2780 igniter has continuity. If the igniter has a low
2781 resistance, then the voltage measured here will be close
2782 to the Li-Po battery voltage. A value greater than 3.2V is
2783 required for a 'GO' status.
2788 <term>Main Igniter Voltage</term>
2791 This indicates whether the main
2792 igniter has continuity. If the igniter has a low
2793 resistance, then the voltage measured here will be close
2794 to the Li-Po battery voltage. A value greater than 3.2V is
2795 required for a 'GO' status.
2800 <term>On-board Data Logging</term>
2803 This indicates whether there is
2804 space remaining on-board to store flight data for the
2805 upcoming flight. If you've downloaded data, but failed
2806 to erase flights, there may not be any space
2807 left. TeleMetrum can store multiple flights, depending
2808 on the configured maximum flight log size. TeleMini
2809 stores only a single flight, so it will need to be
2810 downloaded and erased after each flight to capture
2811 data. This only affects on-board flight logging; the
2812 altimeter will still transmit telemetry and fire
2813 ejection charges at the proper times.
2818 <term>GPS Locked</term>
2821 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
2822 currently able to compute position information. GPS requires
2823 at least 4 satellites to compute an accurate position.
2828 <term>GPS Ready</term>
2831 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
2832 10 consecutive positions without losing lock. This ensures
2833 that the GPS receiver has reliable reception from the
2841 The Launchpad tab also shows the computed launch pad position
2842 and altitude, averaging many reported positions to improve the
2843 accuracy of the fix.
2848 <title>Downloading Flight Logs</title>
2850 AltosDroid always saves every bit of telemetry data it
2851 receives. To download that to a computer for use with AltosUI,
2852 simply remove the SD card from your Android device, or connect
2853 your device to your computer's USB port and browse the files
2854 on that device. You will find '.telem' files in the TeleMetrum
2855 directory that will work with AltosUI directly.
2860 <title>Using Altus Metrum Products</title>
2862 <title>Being Legal</title>
2864 First off, in the US, you need an <ulink url="http://www.altusmetrum.org/Radio/">amateur radio license</ulink> or
2865 other authorization to legally operate the radio transmitters that are part
2870 <title>In the Rocket</title>
2872 In the rocket itself, you just need a flight computer and
2873 a single-cell, 3.7 volt nominal Li-Po rechargeable battery. An
2874 850mAh battery weighs less than a 9V alkaline battery, and will
2875 run a TeleMetrum or TeleMega for hours.
2876 A 110mAh battery weighs less than a triple A battery and is a good
2877 choice for use with TeleMini.
2880 By default, we ship flight computers with a simple wire antenna.
2881 If your electronics bay or the air-frame it resides within is made
2882 of carbon fiber, which is opaque to RF signals, you may prefer to
2883 install an SMA connector so that you can run a coaxial cable to an
2884 antenna mounted elsewhere in the rocket. However, note that the
2885 GPS antenna is fixed on all current products, so you really want
2886 to install the flight computer in a bay made of RF-transparent
2887 materials if at all possible.
2891 <title>On the Ground</title>
2893 To receive the data stream from the rocket, you need an antenna and short
2894 feed-line connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. If possible, use an SMA to BNC
2895 adapter instead of feedline between the antenna feedpoint and
2896 TeleDongle, as this will give you the best performance. The
2897 TeleDongle in turn plugs directly into the USB port on a notebook
2898 computer. Because TeleDongle looks like a simple serial port, your computer
2899 does not require special device drivers... just plug it in.
2902 The GUI tool, AltosUI, is written in Java and runs across
2903 Linux, Mac OS and Windows. There's also a suite of C tools
2904 for Linux which can perform most of the same tasks.
2907 Alternatively, a TeleBT attached with an SMA to BNC adapter at the
2908 feed point of a hand-held yagi used in conjunction with an Android
2909 device running AltosDroid makes an outstanding ground station.
2912 After the flight, you can use the radio link to extract the more detailed data
2913 logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
2914 TeleMetrum board directly. Pulling out the data without having to open up
2915 the rocket is pretty cool! A USB cable is also how you charge the Li-Po
2916 battery, so you'll want one of those anyway... the same cable used by lots
2917 of digital cameras and other modern electronic stuff will work fine.
2920 If your rocket lands out of sight, you may enjoy having a hand-held
2921 GPS receiver, so that you can put in a way-point for the last
2922 reported rocket position before touch-down. This makes looking for
2923 your rocket a lot like Geo-Caching... just go to the way-point and
2924 look around starting from there. AltosDroid on an Android device
2925 with GPS receiver works great for this, too!
2928 You may also enjoy having a ham radio “HT” that covers the 70cm band... you
2929 can use that with your antenna to direction-find the rocket on the ground
2930 the same way you can use a Walston or Beeline tracker. This can be handy
2931 if the rocket is hiding in sage brush or a tree, or if the last GPS position
2932 doesn't get you close enough because the rocket dropped into a canyon, or
2933 the wind is blowing it across a dry lake bed, or something like that... Keith
2934 currently uses a Yaesu VX-7R, Bdale has a Baofung UV-5R
2935 which isn't as nice, but was a whole lot cheaper.
2938 So, to recap, on the ground the hardware you'll need includes:
2939 <orderedlist inheritnum='inherit' numeration='arabic'>
2942 an antenna and feed-line or adapter
2957 optionally, a hand-held GPS receiver
2962 optionally, an HT or receiver covering 435 MHz
2968 The best hand-held commercial directional antennas we've found for radio
2969 direction finding rockets are from
2970 <ulink url="http://www.arrowantennas.com/" >
2973 The 440-3 and 440-5 are both good choices for finding a
2974 TeleMetrum- or TeleMini- equipped rocket when used with a suitable
2975 70cm HT. TeleDongle and an SMA to BNC adapter fit perfectly
2976 between the driven element and reflector of Arrow antennas.
2980 <title>Data Analysis</title>
2982 Our software makes it easy to log the data from each flight, both the
2983 telemetry received during the flight itself, and the more
2984 complete data log recorded in the flash memory on the altimeter
2985 board. Once this data is on your computer, our post-flight tools make it
2986 easy to quickly get to the numbers everyone wants, like apogee altitude,
2987 max acceleration, and max velocity. You can also generate and view a
2988 standard set of plots showing the altitude, acceleration, and
2989 velocity of the rocket during flight. And you can even export a TeleMetrum data file
2990 usable with Google Maps and Google Earth for visualizing the flight path
2991 in two or three dimensions!
2994 Our ultimate goal is to emit a set of files for each flight that can be
2995 published as a web page per flight, or just viewed on your local disk with
3000 <title>Future Plans</title>
3002 We've designed a simple GPS based radio tracker called TeleGPS.
3003 If all goes well, we hope to introduce this in the first
3007 We have designed and prototyped several “companion boards” that
3008 can attach to the companion connector on TeleMetrum and TeleMega
3009 flight computers to collect more data, provide more pyro channels,
3010 and so forth. We do not yet know if or when any of these boards
3011 will be produced in enough quantity to sell. If you have specific
3012 interests for data collection or control of events in your rockets
3013 beyond the capabilities of our existing productions, please let
3017 Because all of our work is open, both the hardware designs and the
3018 software, if you have some great idea for an addition to the current
3019 Altus Metrum family, feel free to dive in and help! Or let us know
3020 what you'd like to see that we aren't already working on, and maybe
3021 we'll get excited about it too...
3025 <ulink url="http://altusmetrum.org/">web site</ulink> for more news
3026 and information as our family of products evolves!
3031 <title>Altimeter Installation Recommendations</title>
3033 Building high-power rockets that fly safely is hard enough. Mix
3034 in some sophisticated electronics and a bunch of radio energy
3035 and some creativity and/or compromise may be required. This chapter
3036 contains some suggestions about how to install Altus Metrum
3037 products into a rocket air-frame, including how to safely and
3038 reliably mix a variety of electronics into the same air-frame.
3041 <title>Mounting the Altimeter</title>
3043 The first consideration is to ensure that the altimeter is
3044 securely fastened to the air-frame. For most of our products, we
3045 prefer nylon standoffs and nylon screws; they're good to at least 50G
3046 and cannot cause any electrical issues on the board. Metal screws
3047 and standoffs are fine, too, just be careful to avoid electrical
3048 shorts! For TeleMini v1.0, we usually cut small pieces of 1/16 inch
3050 under the screw holes, and then take 2x56 nylon screws and
3051 screw them through the TeleMini mounting holes, through the
3052 balsa and into the underlying material.
3054 <orderedlist inheritnum='inherit' numeration='arabic'>
3057 Make sure accelerometer-equipped products like TeleMetrum and
3058 TeleMega are aligned precisely along the axis of
3059 acceleration so that the accelerometer can accurately
3060 capture data during the flight.
3065 Watch for any metal touching components on the
3066 board. Shorting out connections on the bottom of the board
3067 can cause the altimeter to fail during flight.
3073 <title>Dealing with the Antenna</title>
3075 The antenna supplied is just a piece of solid, insulated,
3076 wire. If it gets damaged or broken, it can be easily
3077 replaced. It should be kept straight and not cut; bending or
3078 cutting it will change the resonant frequency and/or
3079 impedance, making it a less efficient radiator and thus
3080 reducing the range of the telemetry signal.
3083 Keeping metal away from the antenna will provide better range
3084 and a more even radiation pattern. In most rockets, it's not
3085 entirely possible to isolate the antenna from metal
3086 components; there are often bolts, all-thread and wires from other
3087 electronics to contend with. Just be aware that the more stuff
3088 like this around the antenna, the lower the range.
3091 Make sure the antenna is not inside a tube made or covered
3092 with conducting material. Carbon fiber is the most common
3093 culprit here -- CF is a good conductor and will effectively
3094 shield the antenna, dramatically reducing signal strength and
3095 range. Metallic flake paint is another effective shielding
3096 material which should be avoided around any antennas.
3099 If the ebay is large enough, it can be convenient to simply
3100 mount the altimeter at one end and stretch the antenna out
3101 inside. Taping the antenna to the sled can keep it straight
3102 under acceleration. If there are metal rods, keep the
3103 antenna as far away as possible.
3106 For a shorter ebay, it's quite practical to have the antenna
3107 run through a bulkhead and into an adjacent bay. Drill a small
3108 hole in the bulkhead, pass the antenna wire through it and
3109 then seal it up with glue or clay. We've also used acrylic
3110 tubing to create a cavity for the antenna wire. This works a
3111 bit better in that the antenna is known to stay straight and
3112 not get folded by recovery components in the bay. Angle the
3113 tubing towards the side wall of the rocket and it ends up
3114 consuming very little space.
3117 If you need to place the UHF antenna at a distance from the
3118 altimeter, you can replace the antenna with an edge-mounted
3119 SMA connector, and then run 50Ω coax from the board to the
3120 antenna. Building a remote antenna is beyond the scope of this
3125 <title>Preserving GPS Reception</title>
3127 The GPS antenna and receiver used in TeleMetrum and TeleMega is
3128 highly sensitive and normally have no trouble tracking enough
3129 satellites to provide accurate position information for
3130 recovering the rocket. However, there are many ways the GPS signal
3131 can end up attenuated, negatively affecting GPS performance.
3132 <orderedlist inheritnum='inherit' numeration='arabic'>
3135 Conductive tubing or coatings. Carbon fiber and metal
3136 tubing, or metallic paint will all dramatically attenuate the
3137 GPS signal. We've never heard of anyone successfully
3138 receiving GPS from inside these materials.
3143 Metal components near the GPS patch antenna. These will
3144 de-tune the patch antenna, changing the resonant frequency
3145 away from the L1 carrier and reduce the effectiveness of the
3146 antenna. You can place as much stuff as you like beneath the
3147 antenna as that's covered with a ground plane. But, keep
3148 wires and metal out from above the patch antenna.
3155 <title>Radio Frequency Interference</title>
3157 Any altimeter will generate RFI; the digital circuits use
3158 high-frequency clocks that spray radio interference across a
3159 wide band. Altus Metrum altimeters generate intentional radio
3160 signals as well, increasing the amount of RF energy around the board.
3163 Rocketry altimeters also use precise sensors measuring air
3164 pressure and acceleration. Tiny changes in voltage can cause
3165 these sensor readings to vary by a huge amount. When the
3166 sensors start mis-reporting data, the altimeter can either
3167 fire the igniters at the wrong time, or not fire them at all.
3170 Voltages are induced when radio frequency energy is
3171 transmitted from one circuit to another. Here are things that
3172 influence the induced voltage and current:
3177 Keep wires from different circuits apart. Moving circuits
3178 further apart will reduce RFI.
3183 Avoid parallel wires from different circuits. The longer two
3184 wires run parallel to one another, the larger the amount of
3185 transferred energy. Cross wires at right angles to reduce
3191 Twist wires from the same circuits. Two wires the same
3192 distance from the transmitter will get the same amount of
3193 induced energy which will then cancel out. Any time you have
3194 a wire pair running together, twist the pair together to
3195 even out distances and reduce RFI. For altimeters, this
3196 includes battery leads, switch hookups and igniter
3202 Avoid resonant lengths. Know what frequencies are present
3203 in the environment and avoid having wire lengths near a
3204 natural resonant length. Altus Metrum products transmit on the
3205 70cm amateur band, so you should avoid lengths that are a
3206 simple ratio of that length; essentially any multiple of ¼
3207 of the wavelength (17.5cm).
3213 <title>The Barometric Sensor</title>
3215 Altusmetrum altimeters measure altitude with a barometric
3216 sensor, essentially measuring the amount of air above the
3217 rocket to figure out how high it is. A large number of
3218 measurements are taken as the altimeter initializes itself to
3219 figure out the pad altitude. Subsequent measurements are then
3220 used to compute the height above the pad.
3223 To accurately measure atmospheric pressure, the ebay
3224 containing the altimeter must be vented outside the
3225 air-frame. The vent must be placed in a region of linear
3226 airflow, have smooth edges, and away from areas of increasing or
3227 decreasing pressure.
3230 All barometric sensors are quite sensitive to chemical damage from
3231 the products of APCP or BP combustion, so make sure the ebay is
3232 carefully sealed from any compartment which contains ejection
3237 <title>Ground Testing</title>
3239 The most important aspect of any installation is careful
3240 ground testing. Bringing an air-frame up to the LCO table which
3241 hasn't been ground tested can lead to delays or ejection
3242 charges firing on the pad, or, even worse, a recovery system
3246 Do a 'full systems' test that includes wiring up all igniters
3247 without any BP and turning on all of the electronics in flight
3248 mode. This will catch any mistakes in wiring and any residual
3249 RFI issues that might accidentally fire igniters at the wrong
3250 time. Let the air-frame sit for several minutes, checking for
3251 adequate telemetry signal strength and GPS lock. If any igniters
3252 fire unexpectedly, find and resolve the issue before loading any
3256 Ground test the ejection charges. Prepare the rocket for
3257 flight, loading ejection charges and igniters. Completely
3258 assemble the air-frame and then use the 'Fire Igniters'
3259 interface through a TeleDongle to command each charge to
3260 fire. Make sure the charge is sufficient to robustly separate
3261 the air-frame and deploy the recovery system.
3266 <title>Updating Device Firmware</title>
3268 TeleMega, TeleMetrum v2 and EasyMini are all programmed directly
3269 over their USB connectors (self programming). TeleMetrum v1, TeleMini and
3270 TeleDongle are all programmed by using another device as a
3271 programmer (pair programming). It's important to recognize which
3272 kind of devices you have before trying to reprogram them.
3275 You may wish to begin by ensuring you have current firmware images.
3276 These are distributed as part of the AltOS software bundle that
3277 also includes the AltosUI ground station program. Newer ground
3278 station versions typically work fine with older firmware versions,
3279 so you don't need to update your devices just to try out new
3280 software features. You can always download the most recent
3281 version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
3284 If you need to update the firmware on a TeleDongle, we recommend
3285 updating the altimeter first, before updating TeleDongle. However,
3286 note that TeleDongle rarely need to be updated. Any firmware version
3287 1.0.1 or later will work, version 1.2.1 may have improved receiver
3288 performance slightly.
3291 Self-programmable devices (TeleMega, TeleMetrum v2 and EasyMini)
3292 are reprogrammed by connecting them to your computer over USB
3296 Updating TeleMega, TeleMetrum v2 or EasyMini Firmware
3298 <orderedlist inheritnum='inherit' numeration='arabic'>
3301 Attach a battery and power switch to the target
3302 device. Power up the device.
3307 Using a Micro USB cable, connect the target device to your
3308 computer's USB socket.
3313 Run AltosUI, and select 'Flash Image' from the File menu.
3318 Select the target device in the Device Selection dialog.
3323 Select the image you want to flash to the device, which
3324 should have a name in the form
3325 <product>-v<product-version>-<software-version>.ihx, such
3326 as TeleMega-v1.0-1.3.0.ihx.
3331 Make sure the configuration parameters are reasonable
3332 looking. If the serial number and/or RF configuration
3333 values aren't right, you'll need to change them.
3338 Hit the 'OK' button and the software should proceed to flash
3339 the device with new firmware, showing a progress bar.
3344 Verify that the device is working by using the 'Configure
3345 Altimeter' item to check over the configuration.
3350 <title>Recovering From Self-Flashing Failure</title>
3352 If the firmware loading fails, it can leave the device
3353 unable to boot. Not to worry, you can force the device to
3354 start the boot loader instead, which will let you try to
3355 flash the device again.
3358 On each device, connecting two pins from one of the exposed
3359 connectors will force the boot loader to start, even if the
3360 regular operating system has been corrupted in some way.
3364 <term>TeleMega</term>
3367 Connect pin 6 and pin 1 of the companion connector. Pin 1
3368 can be identified by the square pad around it, and then
3369 the pins could sequentially across the board. Be very
3370 careful to <emphasis>not</emphasis> short pin 8 to
3371 anything as that is connected directly to the battery. Pin
3372 7 carries 3.3V and the board will crash if that is
3373 connected to pin 1, but shouldn't damage the board.
3378 <term>TeleMetrum v2</term>
3381 Connect pin 6 and pin 1 of the companion connector. Pin 1
3382 can be identified by the square pad around it, and then
3383 the pins could sequentially across the board. Be very
3384 careful to <emphasis>not</emphasis> short pin 8 to
3385 anything as that is connected directly to the battery. Pin
3386 7 carries 3.3V and the board will crash if that is
3387 connected to pin 1, but shouldn't damage the board.
3392 <term>EasyMini</term>
3395 Connect pin 6 and pin 1 of the debug connector, which is
3396 the six holes next to the beeper. Pin 1 can be identified
3397 by the square pad around it, and then the pins could
3398 sequentially across the board, making Pin 6 the one on the
3399 other end of the row.
3407 <title>Pair Programming</title>
3409 The big concept to understand is that you have to use a
3410 TeleMega, TeleMetrum or TeleDongle as a programmer to update a
3411 pair programmed device. Due to limited memory resources in the
3412 cc1111, we don't support programming directly over USB for these
3417 <title>Updating TeleMetrum v1.x Firmware</title>
3418 <orderedlist inheritnum='inherit' numeration='arabic'>
3421 Find the 'programming cable' that you got as part of the starter
3422 kit, that has a red 8-pin MicroMaTch connector on one end and a
3423 red 4-pin MicroMaTch connector on the other end.
3428 Take the 2 screws out of the TeleDongle case to get access
3429 to the circuit board.
3434 Plug the 8-pin end of the programming cable to the
3435 matching connector on the TeleDongle, and the 4-pin end to the
3436 matching connector on the TeleMetrum.
3437 Note that each MicroMaTch connector has an alignment pin that
3438 goes through a hole in the PC board when you have the cable
3444 Attach a battery to the TeleMetrum board.
3449 Plug the TeleDongle into your computer's USB port, and power
3455 Run AltosUI, and select 'Flash Image' from the File menu.
3460 Pick the TeleDongle device from the list, identifying it as the
3466 Select the image you want put on the TeleMetrum, which should have a
3467 name in the form telemetrum-v1.2-1.0.0.ihx. It should be visible
3468 in the default directory, if not you may have to poke around
3469 your system to find it.
3474 Make sure the configuration parameters are reasonable
3475 looking. If the serial number and/or RF configuration
3476 values aren't right, you'll need to change them.
3481 Hit the 'OK' button and the software should proceed to flash
3482 the TeleMetrum with new firmware, showing a progress bar.
3487 Confirm that the TeleMetrum board seems to have updated OK, which you
3488 can do by plugging in to it over USB and using a terminal program
3489 to connect to the board and issue the 'v' command to check
3495 If something goes wrong, give it another try.
3501 <title>Updating TeleMini Firmware</title>
3502 <orderedlist inheritnum='inherit' numeration='arabic'>
3505 You'll need a special 'programming cable' to reprogram the
3506 TeleMini. You can make your own using an 8-pin MicroMaTch
3507 connector on one end and a set of four pins on the other.
3512 Take the 2 screws out of the TeleDongle case to get access
3513 to the circuit board.
3518 Plug the 8-pin end of the programming cable to the matching
3519 connector on the TeleDongle, and the 4-pins into the holes
3520 in the TeleMini circuit board. Note that the MicroMaTch
3521 connector has an alignment pin that goes through a hole in
3522 the PC board when you have the cable oriented correctly, and
3523 that pin 1 on the TeleMini board is marked with a square pad
3524 while the other pins have round pads.
3529 Attach a battery to the TeleMini board.
3534 Plug the TeleDongle into your computer's USB port, and power
3540 Run AltosUI, and select 'Flash Image' from the File menu.
3545 Pick the TeleDongle device from the list, identifying it as the
3551 Select the image you want put on the TeleMini, which should have a
3552 name in the form telemini-v1.0-1.0.0.ihx. It should be visible
3553 in the default directory, if not you may have to poke around
3554 your system to find it.
3559 Make sure the configuration parameters are reasonable
3560 looking. If the serial number and/or RF configuration
3561 values aren't right, you'll need to change them.
3566 Hit the 'OK' button and the software should proceed to flash
3567 the TeleMini with new firmware, showing a progress bar.
3572 Confirm that the TeleMini board seems to have updated OK, which you
3573 can do by configuring it over the radio link through the TeleDongle, or
3574 letting it come up in “flight” mode and listening for telemetry.
3579 If something goes wrong, give it another try.
3585 <title>Updating TeleDongle Firmware</title>
3587 Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
3588 firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
3590 <orderedlist inheritnum='inherit' numeration='arabic'>
3593 Find the 'programming cable' that you got as part of the starter
3594 kit, that has a red 8-pin MicroMaTch connector on one end and a
3595 red 4-pin MicroMaTch connector on the other end.
3600 Find the USB cable that you got as part of the starter kit, and
3601 plug the “mini” end in to the mating connector on TeleMetrum or TeleDongle.
3606 Take the 2 screws out of the TeleDongle case to get access
3607 to the circuit board.
3612 Plug the 8-pin end of the programming cable to the
3613 matching connector on the programmer, and the 4-pin end to the
3614 matching connector on the TeleDongle.
3615 Note that each MicroMaTch connector has an alignment pin that
3616 goes through a hole in the PC board when you have the cable
3622 Attach a battery to the TeleMetrum board if you're using one.
3627 Plug both the programmer and the TeleDongle into your computer's USB
3628 ports, and power up the programmer.
3633 Run AltosUI, and select 'Flash Image' from the File menu.
3638 Pick the programmer device from the list, identifying it as the
3644 Select the image you want put on the TeleDongle, which should have a
3645 name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
3646 in the default directory, if not you may have to poke around
3647 your system to find it.
3652 Make sure the configuration parameters are reasonable
3653 looking. If the serial number and/or RF configuration
3654 values aren't right, you'll need to change them. The TeleDongle
3655 serial number is on the “bottom” of the circuit board, and can
3656 usually be read through the translucent blue plastic case without
3657 needing to remove the board from the case.
3662 Hit the 'OK' button and the software should proceed to flash
3663 the TeleDongle with new firmware, showing a progress bar.
3668 Confirm that the TeleDongle board seems to have updated OK, which you
3669 can do by plugging in to it over USB and using a terminal program
3670 to connect to the board and issue the 'v' command to check
3671 the version, etc. Once you're happy, remove the programming cable
3672 and put the cover back on the TeleDongle.
3677 If something goes wrong, give it another try.
3682 Be careful removing the programming cable from the locking 8-pin
3683 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
3684 screwdriver or knife blade to gently pry the locking ears out
3685 slightly to extract the connector. We used a locking connector on
3686 TeleMetrum to help ensure that the cabling to companion boards
3687 used in a rocket don't ever come loose accidentally in flight.
3692 <title>Hardware Specifications</title>
3695 TeleMega Specifications
3700 Recording altimeter for model rocketry.
3705 Supports dual deployment and four auxiliary pyro channels
3706 (a total of 6 events).
3711 70cm 40mW ham-band transceiver for telemetry down-link.
3716 Barometric pressure sensor good to 100k feet MSL.
3721 1-axis high-g accelerometer for motor characterization, capable of
3727 9-axis IMU including integrated 3-axis accelerometer,
3728 3-axis gyroscope and 3-axis magnetometer.
3733 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
3738 On-board 8 Megabyte non-volatile memory for flight data storage.
3743 USB interface for battery charging, configuration, and data recovery.
3748 Fully integrated support for Li-Po rechargeable batteries.
3753 Can use either main system Li-Po or optional separate pyro battery
3759 3.25 x 1.25 inch board designed to fit inside 38mm air-frame coupler tube.
3766 TeleMetrum v2 Specifications
3771 Recording altimeter for model rocketry.
3776 Supports dual deployment (can fire 2 ejection charges).
3781 70cm, 40mW ham-band transceiver for telemetry down-link.
3786 Barometric pressure sensor good to 100k feet MSL.
3791 1-axis high-g accelerometer for motor characterization, capable of
3797 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
3802 On-board 8 Megabyte non-volatile memory for flight data storage.
3807 USB interface for battery charging, configuration, and data recovery.
3812 Fully integrated support for Li-Po rechargeable batteries.
3817 Uses Li-Po to fire e-matches, can be modified to support
3818 optional separate pyro battery if needed.
3823 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
3829 <title>TeleMetrum v1 Specifications</title>
3833 Recording altimeter for model rocketry.
3838 Supports dual deployment (can fire 2 ejection charges).
3843 70cm, 10mW ham-band transceiver for telemetry down-link.
3848 Barometric pressure sensor good to 45k feet MSL.
3853 1-axis high-g accelerometer for motor characterization, capable of
3854 +/- 50g using default part.
3859 On-board, integrated GPS receiver with 5Hz update rate capability.
3864 On-board 1 megabyte non-volatile memory for flight data storage.
3869 USB interface for battery charging, configuration, and data recovery.
3874 Fully integrated support for Li-Po rechargeable batteries.
3879 Uses Li-Po to fire e-matches, can be modified to support
3880 optional separate pyro battery if needed.
3885 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
3892 TeleMini v2.0 Specifications
3897 Recording altimeter for model rocketry.
3902 Supports dual deployment (can fire 2 ejection charges).
3907 70cm, 10mW ham-band transceiver for telemetry down-link.
3912 Barometric pressure sensor good to 100k feet MSL.
3917 On-board 1 megabyte non-volatile memory for flight data storage.
3922 USB interface for configuration, and data recovery.
3927 Support for Li-Po rechargeable batteries (using an
3928 external charger), or any 3.7-15V external battery.
3933 Uses Li-Po to fire e-matches, can be modified to support
3934 optional separate pyro battery if needed.
3939 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
3946 TeleMini v1.0 Specifications
3951 Recording altimeter for model rocketry.
3956 Supports dual deployment (can fire 2 ejection charges).
3961 70cm, 10mW ham-band transceiver for telemetry down-link.
3966 Barometric pressure sensor good to 45k feet MSL.
3971 On-board 5 kilobyte non-volatile memory for flight data storage.
3976 RF interface for configuration, and data recovery.
3981 Support for Li-Po rechargeable batteries, using an external charger.
3986 Uses Li-Po to fire e-matches, can be modified to support
3987 optional separate pyro battery if needed.
3992 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube.
3999 EasyMini Specifications
4004 Recording altimeter for model rocketry.
4009 Supports dual deployment (can fire 2 ejection charges).
4014 Barometric pressure sensor good to 100k feet MSL.
4019 On-board 1 megabyte non-volatile memory for flight data storage.
4024 USB interface for configuration, and data recovery.
4029 Support for Li-Po rechargeable batteries (using an
4030 external charger), or any 3.7-15V external battery.
4035 Uses Li-Po to fire e-matches, can be modified to support
4036 optional separate pyro battery if needed.
4041 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
4050 <emphasis>TeleMetrum seems to shut off when disconnected from the
4051 computer.</emphasis> <?linebreak?>
4052 Make sure the battery is adequately charged. Remember the
4053 unit will pull more power than the USB port can deliver before the
4054 GPS enters “locked” mode. The battery charges best when TeleMetrum
4058 <emphasis>It's impossible to stop the TeleDongle when it's in “p” mode, I have
4059 to unplug the USB cable? </emphasis><?linebreak?>
4060 Make sure you have tried to “escape out” of
4061 this mode. If this doesn't work the reboot procedure for the
4062 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
4063 outgoing buffer IF your “escape out” ('~~') does not work.
4064 At this point using either 'ao-view' (or possibly
4065 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
4069 <emphasis>The amber LED (on the TeleMetrum) lights up when both
4070 battery and USB are connected. Does this mean it's charging?
4071 </emphasis><?linebreak?>
4072 Yes, the yellow LED indicates the charging at the 'regular' rate.
4073 If the led is out but the unit is still plugged into a USB port,
4074 then the battery is being charged at a 'trickle' rate.
4077 <emphasis>There are no “dit-dah-dah-dit” sound or lights like the manual
4078 mentions?</emphasis><?linebreak?>
4079 That's the “pad” mode. Weak batteries might be the problem.
4080 It is also possible that the flight computer is horizontal and the
4082 is instead a “dit-dit” meaning 'idle'. For TeleMini, it's possible that
4083 it received a command packet which would have left it in “pad” mode.
4086 <emphasis>How do I save flight data?</emphasis><?linebreak?>
4087 Live telemetry is written to file(s) whenever AltosUI is connected
4088 to the TeleDongle. The file area defaults to ~/TeleMetrum
4089 but is easily changed using the menus in AltosUI. The files that
4090 are written end in '.telem'. The after-flight
4091 data-dumped files will end in .eeprom and represent continuous data
4092 unlike the .telem files that are subject to losses
4093 along the RF data path.
4094 See the above instructions on what and how to save the eeprom stored
4095 data after physically retrieving your altimeter. Make sure to save
4096 the on-board data after each flight; while the TeleMetrum can store
4097 multiple flights, you never know when you'll lose the altimeter...
4101 <title>Notes for Older Software</title>
4104 Before AltosUI was written, using Altus Metrum devices required
4105 some finesse with the Linux command line. There was a limited
4106 GUI tool, ao-view, which provided functionality similar to the
4107 Monitor Flight window in AltosUI, but everything else was a
4108 fairly 80's experience. This appendix includes documentation for
4109 using that software.
4113 Both TeleMetrum and TeleDongle can be directly communicated
4114 with using USB ports. The first thing you should try after getting
4115 both units plugged into to your computer's USB port(s) is to run
4116 'ao-list' from a terminal-window to see what port-device-name each
4117 device has been assigned by the operating system.
4118 You will need this information to access the devices via their
4119 respective on-board firmware and data using other command line
4120 programs in the AltOS software suite.
4123 TeleMini can be communicated with through a TeleDongle device
4124 over the radio link. When first booted, TeleMini listens for a
4125 TeleDongle device and if it receives a packet, it goes into
4126 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be
4127 launched. The easiest way to get it talking is to start the
4128 communication link on the TeleDongle and the power up the
4132 To access the device's firmware for configuration you need a terminal
4133 program such as you would use to talk to a modem. The software
4134 authors prefer using the program 'cu' which comes from the UUCP package
4135 on most Unix-like systems such as Linux. An example command line for
4136 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
4137 indicated from running the
4138 ao-list program. Another reasonable terminal program for Linux is
4139 'cutecom'. The default 'escape'
4140 character used by CU (i.e. the character you use to
4141 issue commands to cu itself instead of sending the command as input
4142 to the connected device) is a '~'. You will need this for use in
4143 only two different ways during normal operations. First is to exit
4144 the program by sending a '~.' which is called a 'escape-disconnect'
4145 and allows you to close-out from 'cu'. The
4146 second use will be outlined later.
4149 All of the Altus Metrum devices share the concept of a two level
4150 command set in their firmware.
4151 The first layer has several single letter commands. Once
4152 you are using 'cu' (or 'cutecom') sending (typing) a '?'
4153 returns a full list of these
4154 commands. The second level are configuration sub-commands accessed
4155 using the 'c' command, for
4156 instance typing 'c?' will give you this second level of commands
4157 (all of which require the
4158 letter 'c' to access). Please note that most configuration options
4159 are stored only in Flash memory; TeleDongle doesn't provide any storage
4160 for these options and so they'll all be lost when you unplug it.
4163 Try setting these configuration ('c' or second level menu) values. A good
4164 place to start is by setting your call sign. By default, the boards
4165 use 'N0CALL' which is cute, but not exactly legal!
4166 Spend a few minutes getting comfortable with the units, their
4167 firmware, and 'cu' (or possibly 'cutecom').
4168 For instance, try to send
4169 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
4170 Verify you can connect and disconnect from the units while in your
4171 terminal program by sending the escape-disconnect mentioned above.
4174 To set the radio frequency, use the 'c R' command to specify the
4175 radio transceiver configuration parameter. This parameter is computed
4176 using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
4177 the standard calibration reference frequency, 'S', (normally 434.550MHz):
4181 Round the result to the nearest integer value.
4182 As with all 'c' sub-commands, follow this with a 'c w' to write the
4183 change to the parameter block in the on-board flash on
4184 your altimeter board if you want the change to stay in place across reboots.
4187 To set the apogee delay, use the 'c d' command.
4188 As with all 'c' sub-commands, follow this with a 'c w' to write the
4189 change to the parameter block in the on-board DataFlash chip.
4192 To set the main deployment altitude, use the 'c m' command.
4193 As with all 'c' sub-commands, follow this with a 'c w' to write the
4194 change to the parameter block in the on-board DataFlash chip.
4197 To calibrate the radio frequency, connect the UHF antenna port to a
4198 frequency counter, set the board to 434.550MHz, and use the 'C'
4199 command to generate a CW carrier. Wait for the transmitter temperature
4200 to stabilize and the frequency to settle down.
4201 Then, divide 434.550 MHz by the
4202 measured frequency and multiply by the current radio cal value show
4203 in the 'c s' command. For an unprogrammed board, the default value
4204 is 1186611 for cc1111 based products and 7119667 for cc1120
4205 based products. Take the resulting integer and program it using the 'c f'
4206 command. Testing with the 'C' command again should show a carrier
4207 within a few tens of Hertz of the intended frequency.
4208 As with all 'c' sub-commands, follow this with a 'c w' to write the
4209 change to the configuration memory.
4212 Note that the 'reboot' command, which is very useful on the altimeters,
4213 will likely just cause problems with the dongle. The *correct* way
4214 to reset the dongle is just to unplug and re-plug it.
4217 A fun thing to do at the launch site and something you can do while
4218 learning how to use these units is to play with the radio link access
4219 between an altimeter and the TeleDongle. Be aware that you *must* create
4220 some physical separation between the devices, otherwise the link will
4221 not function due to signal overload in the receivers in each device.
4224 Now might be a good time to take a break and read the rest of this
4225 manual, particularly about the two “modes” that the altimeters
4226 can be placed in. TeleMetrum uses the position of the device when booting
4227 up will determine whether the unit is in “pad” or “idle” mode. TeleMini
4228 enters “idle” mode when it receives a command packet within the first 5 seconds
4229 of being powered up, otherwise it enters “pad” mode.
4232 You can access an altimeter in idle mode from the TeleDongle's USB
4233 connection using the radio link
4234 by issuing a 'p' command to the TeleDongle. Practice connecting and
4235 disconnecting ('~~' while using 'cu') from the altimeter. If
4236 you cannot escape out of the “p” command, (by using a '~~' when in
4237 CU) then it is likely that your kernel has issues. Try a newer version.
4240 Using this radio link allows you to configure the altimeter, test
4241 fire e-matches and igniters from the flight line, check pyro-match
4242 continuity and so forth. You can leave the unit turned on while it
4243 is in 'idle mode' and then place the
4244 rocket vertically on the launch pad, walk away and then issue a
4245 reboot command. The altimeter will reboot and start sending data
4246 having changed to the “pad” mode. If the TeleDongle is not receiving
4247 this data, you can disconnect 'cu' from the TeleDongle using the
4248 procedures mentioned above and THEN connect to the TeleDongle from
4249 inside 'ao-view'. If this doesn't work, disconnect from the
4250 TeleDongle, unplug it, and try again after plugging it back in.
4253 In order to reduce the chance of accidental firing of pyrotechnic
4254 charges, the command to fire a charge is intentionally somewhat
4255 difficult to type, and the built-in help is slightly cryptic to
4256 prevent accidental echoing of characters from the help text back at
4257 the board from firing a charge. The command to fire the apogee
4258 drogue charge is 'i DoIt drogue' and the command to fire the main
4259 charge is 'i DoIt main'.
4262 On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
4263 and 'ao-view' will both auditorily announce and visually indicate
4265 Now you can launch knowing that you have a good data path and
4266 good satellite lock for flight data and recovery. Remember
4267 you MUST tell ao-view to connect to the TeleDongle explicitly in
4268 order for ao-view to be able to receive data.
4271 The altimeters provide RDF (radio direction finding) tones on
4272 the pad, during descent and after landing. These can be used to
4273 locate the rocket using a directional antenna; the signal
4274 strength providing an indication of the direction from receiver to rocket.
4277 TeleMetrum also provides GPS tracking data, which can further simplify
4278 locating the rocket once it has landed. (The last good GPS data
4279 received before touch-down will be on the data screen of 'ao-view'.)
4282 Once you have recovered the rocket you can download the eeprom
4283 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
4284 either a USB cable or over the radio link using TeleDongle.
4285 And by following the man page for 'ao-postflight' you can create
4286 various data output reports, graphs, and even KML data to see the
4287 flight trajectory in Google-earth. (Moving the viewing angle making
4288 sure to connect the yellow lines while in Google-earth is the proper
4292 As for ao-view.... some things are in the menu but don't do anything
4293 very useful. The developers have stopped working on ao-view to focus
4294 on a new, cross-platform ground station program. So ao-view may or
4295 may not be updated in the future. Mostly you just use
4296 the Log and Device menus. It has a wonderful display of the incoming
4297 flight data and I am sure you will enjoy what it has to say to you
4298 once you enable the voice output!
4302 <title>Drill Templates</title>
4304 These images, when printed, provide precise templates for the
4305 mounting holes in Altus Metrum flight computers
4308 <title>TeleMega template</title>
4310 TeleMega has overall dimensions of 1.250 x 3.250 inches, and
4311 the mounting holes are sized for use with 4-40 or M3 screws.
4314 <mediaobject id="TeleMegaTemplate">
4316 <imagedata format="SVG" fileref="telemega-outline.svg"/>
4322 <title>TeleMetrum template</title>
4324 TeleMetrum has overall dimensions of 1.000 x 2.750 inches, and the
4325 mounting holes are sized for use with 4-40 or M3 screws.
4328 <mediaobject id="TeleMetrumTemplate">
4330 <imagedata format="SVG" fileref="telemetrum.svg"/>
4336 <title>TeleMini v2/EasyMini template</title>
4338 TeleMini v2 and EasyMini have overall dimensions of 0.800 x 1.500 inches, and the
4339 mounting holes are sized for use with 4-40 or M3 screws.
4342 <mediaobject id="MiniTemplate">
4344 <imagedata format="SVG" fileref="easymini-outline.svg"/>
4350 <title>TeleMini v1 template</title>
4352 TeleMini has overall dimensions of 0.500 x 1.500 inches, and the
4353 mounting holes are sized for use with 2-56 or M2 screws.
4356 <mediaobject id="TeleMiniTemplate">
4358 <imagedata format="SVG" fileref="telemini.svg"/>
4365 <title>Calibration</title>
4367 There are only two calibrations required for TeleMetrum and
4368 TeleMega, and only one for TeleDongle, TeleMini and EasyMini.
4369 All boards are shipped from the factory pre-calibrated, but
4370 the procedures are documented here in case they are ever
4371 needed. Re-calibration is not supported by AltosUI, you must
4372 connect to the board with a serial terminal program and
4373 interact directly with the on-board command interpreter to
4377 <title>Radio Frequency</title>
4379 The radio frequency is synthesized from a clock based on the
4380 crystal on the board. The actual frequency of this oscillator
4381 must be measured to generate a calibration constant. While our
4383 bandwidth is wide enough to allow boards to communicate even when
4384 their oscillators are not on exactly the same frequency, performance
4385 is best when they are closely matched.
4386 Radio frequency calibration requires a calibrated frequency counter.
4387 Fortunately, once set, the variation in frequency due to aging and
4388 temperature changes is small enough that re-calibration by customers
4389 should generally not be required.
4392 To calibrate the radio frequency, connect the UHF antenna
4393 port to a frequency counter, set the board to 434.550MHz,
4394 and use the 'C' command in the on-board command interpreter
4395 to generate a CW carrier. For USB-enabled boards, this is
4396 best done over USB. For TeleMini v1, note that the only way
4397 to escape the 'C' command is via power cycle since the board
4398 will no longer be listening for commands once it starts
4399 generating a CW carrier.
4402 Wait for the transmitter temperature to stabilize and the frequency
4403 to settle down. Then, divide 434.550 MHz by the
4404 measured frequency and multiply by the current radio cal value show
4405 in the 'c s' command. For an unprogrammed board, the default value
4406 is 1186611. Take the resulting integer and program it using the 'c f'
4407 command. Testing with the 'C' command again should show a carrier
4408 within a few tens of Hertz of the intended frequency.
4409 As with all 'c' sub-commands, follow this with a 'c w' to write the
4410 change to the parameter block in the on-board storage chip.
4413 Note that any time you re-do the radio frequency calibration, the
4414 radio frequency is reset to the default 434.550 Mhz. If you want
4415 to use another frequency, you will have to set that again after
4416 calibration is completed.
4420 <title>TeleMetrum and TeleMega Accelerometers</title>
4422 While barometric sensors are factory-calibrated,
4423 accelerometers are not, and so each must be calibrated once
4424 installed in a flight computer. Explicitly calibrating the
4425 accelerometers also allows us to load any compatible device.
4426 We perform a two-point calibration using gravity.
4429 To calibrate the acceleration sensor, use the 'c a 0' command. You
4430 will be prompted to orient the board vertically with the UHF antenna
4431 up and press a key, then to orient the board vertically with the
4432 UHF antenna down and press a key. Note that the accuracy of this
4433 calibration depends primarily on how perfectly vertical and still
4434 the board is held during the cal process. As with all 'c'
4435 sub-commands, follow this with a 'c w' to write the
4436 change to the parameter block in the on-board DataFlash chip.
4439 The +1g and -1g calibration points are included in each telemetry
4440 frame and are part of the header stored in onboard flash to be
4441 downloaded after flight. We always store and return raw ADC
4442 samples for each sensor... so nothing is permanently “lost” or
4443 “damaged” if the calibration is poor.
4446 In the unlikely event an accel cal goes badly, it is possible
4447 that TeleMetrum or TeleMega may always come up in 'pad mode'
4448 and as such not be listening to either the USB or radio link.
4449 If that happens, there is a special hook in the firmware to
4450 force the board back in to 'idle mode' so you can re-do the
4451 cal. To use this hook, you just need to ground the SPI clock
4452 pin at power-on. This pin is available as pin 2 on the 8-pin
4453 companion connector, and pin 1 is ground. So either
4454 carefully install a fine-gauge wire jumper between the two
4455 pins closest to the index hole end of the 8-pin connector, or
4456 plug in the programming cable to the 8-pin connector and use
4457 a small screwdriver or similar to short the two pins closest
4458 to the index post on the 4-pin end of the programming cable,
4459 and power up the board. It should come up in 'idle mode'
4460 (two beeps), allowing a re-cal.
4465 <title>Release Notes</title>
4467 <title>Version 1.3.2</title>
4469 xmlns:xi="http://www.w3.org/2001/XInclude"
4470 href="release-notes-1.3.2.xsl"
4471 xpointer="xpointer(/article/*)"/>
4474 <title>Version 1.3.1</title>
4476 xmlns:xi="http://www.w3.org/2001/XInclude"
4477 href="release-notes-1.3.1.xsl"
4478 xpointer="xpointer(/article/*)"/>
4481 <title>Version 1.3</title>
4483 xmlns:xi="http://www.w3.org/2001/XInclude"
4484 href="release-notes-1.3.xsl"
4485 xpointer="xpointer(/article/*)"/>
4488 <title>Version 1.2.1</title>
4490 xmlns:xi="http://www.w3.org/2001/XInclude"
4491 href="release-notes-1.2.1.xsl"
4492 xpointer="xpointer(/article/*)"/>
4495 <title>Version 1.2</title>
4497 xmlns:xi="http://www.w3.org/2001/XInclude"
4498 href="release-notes-1.2.xsl"
4499 xpointer="xpointer(/article/*)"/>
4502 <title>Version 1.1.1</title>
4504 xmlns:xi="http://www.w3.org/2001/XInclude"
4505 href="release-notes-1.1.1.xsl"
4506 xpointer="xpointer(/article/*)"/>
4509 <title>Version 1.1</title>
4511 xmlns:xi="http://www.w3.org/2001/XInclude"
4512 href="release-notes-1.1.xsl"
4513 xpointer="xpointer(/article/*)"/>
4516 <title>Version 1.0.1</title>
4518 xmlns:xi="http://www.w3.org/2001/XInclude"
4519 href="release-notes-1.0.1.xsl"
4520 xpointer="xpointer(/article/*)"/>
4523 <title>Version 0.9.2</title>
4525 xmlns:xi="http://www.w3.org/2001/XInclude"
4526 href="release-notes-0.9.2.xsl"
4527 xpointer="xpointer(/article/*)"/>
4530 <title>Version 0.9</title>
4532 xmlns:xi="http://www.w3.org/2001/XInclude"
4533 href="release-notes-0.9.xsl"
4534 xpointer="xpointer(/article/*)"/>
4537 <title>Version 0.8</title>
4539 xmlns:xi="http://www.w3.org/2001/XInclude"
4540 href="release-notes-0.8.xsl"
4541 xpointer="xpointer(/article/*)"/>
4544 <title>Version 0.7.1</title>
4546 xmlns:xi="http://www.w3.org/2001/XInclude"
4547 href="release-notes-0.7.1.xsl"
4548 xpointer="xpointer(/article/*)"/>
4553 <!-- LocalWords: Altusmetrum
projects / fw / altos / blob