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2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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5 <title>The Altus Metrum System</title>
6 <subtitle>An Owner's Manual for Altus Metrum Rocketry Electronics</subtitle>
9 <firstname>Bdale</firstname>
10 <surname>Garbee</surname>
13 <firstname>Keith</firstname>
14 <surname>Packard</surname>
17 <firstname>Bob</firstname>
18 <surname>Finch</surname>
21 <firstname>Anthony</firstname>
22 <surname>Towns</surname>
26 <holder>Bdale Garbee and Keith Packard</holder>
30 This document is released under the terms of the
31 <ulink url="http://creativecommons.org/licenses/by-sa/3.0/">
32 Creative Commons ShareAlike 3.0
39 <revnumber>1.3</revnumber>
40 <date>12 November 2013</date>
42 Updated for software version 1.3. Version 1.3 adds support
43 for TeleMega, TeleMetrum v2.0, TeleMini v2.0 and EasyMini
44 and fixes bugs in AltosUI and the AltOS firmware.
48 <revnumber>1.2.1</revnumber>
49 <date>21 May 2013</date>
51 Updated for software version 1.2. Version 1.2 adds support
52 for TeleBT and AltosDroid. It also adds a few minor features
53 and fixes bugs in AltosUI and the AltOS firmware.
57 <revnumber>1.2</revnumber>
58 <date>18 April 2013</date>
60 Updated for software version 1.2. Version 1.2 adds support
61 for MicroPeak and the MicroPeak USB interface.
65 <revnumber>1.1.1</revnumber>
66 <date>16 September 2012</date>
68 Updated for software version 1.1.1 Version 1.1.1 fixes a few
69 bugs found in version 1.1.
73 <revnumber>1.1</revnumber>
74 <date>13 September 2012</date>
76 Updated for software version 1.1. Version 1.1 has new
77 features but is otherwise compatible with version 1.0.
81 <revnumber>1.0</revnumber>
82 <date>24 August 2011</date>
84 Updated for software version 1.0. Note that 1.0 represents a
85 telemetry format change, meaning both ends of a link
86 (TeleMetrum/TeleMini and TeleDongle) must be updated or
87 communications will fail.
91 <revnumber>0.9</revnumber>
92 <date>18 January 2011</date>
94 Updated for software version 0.9. Note that 0.9 represents a
95 telemetry format change, meaning both ends of a link (TeleMetrum and
96 TeleDongle) must be updated or communications will fail.
100 <revnumber>0.8</revnumber>
101 <date>24 November 2010</date>
102 <revremark>Updated for software version 0.8 </revremark>
107 <title>Acknowledgments</title>
109 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing “The
110 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
111 Kit” which formed the basis of the original Getting Started chapter
112 in this manual. Bob was one of our first customers for a production
113 TeleMetrum, and his continued enthusiasm and contributions
114 are immensely gratifying and highly appreciated!
117 And thanks to Anthony (AJ) Towns for major contributions including
118 the AltosUI graphing and site map code and associated documentation.
119 Free software means that our customers and friends can become our
120 collaborators, and we certainly appreciate this level of
124 Have fun using these products, and we hope to meet all of you
125 out on the rocket flight line somewhere.
128 NAR #87103, TRA #12201
130 Keith Packard, KD7SQG
131 NAR #88757, TRA #12200
136 <title>Introduction and Overview</title>
138 Welcome to the Altus Metrum community! Our circuits and software reflect
139 our passion for both hobby rocketry and Free Software. We hope their
140 capabilities and performance will delight you in every way, but by
141 releasing all of our hardware and software designs under open licenses,
142 we also hope to empower you to take as active a role in our collective
146 The first device created for our community was TeleMetrum, a dual
147 deploy altimeter with fully integrated GPS and radio telemetry
148 as standard features, and a “companion interface” that will
149 support optional capabilities in the future. The latest version
150 of TeleMetrum, v2.0, has all of the same features but with
151 improved sensors and radio to offer increased performance.
154 Our second device was TeleMini, a dual deploy altimeter with
155 radio telemetry and radio direction finding. The first version
156 of this device was only 13mm by 38mm (½ inch by 1½ inches) and
157 could fit easily in an 18mm air-frame. The latest version, v2.0,
158 includes a beeper, USB data download and extended on-board
159 flight logging, along with an improved barometric sensor.
162 TeleMega is our most sophisticated device, including six pyro
163 channels (four of which are fully programmable), integrated GPS,
164 integrated gyroscopes for staging/air-start inhibit and high
165 performance telemetry.
168 EasyMini is a dual-deploy altimeter with logging and built-in
172 TeleDongle was our first ground station, providing a USB to RF
173 interfaces for communicating with the altimeters. Combined with
174 your choice of antenna and notebook computer, TeleDongle and our
175 associated user interface software form a complete ground
176 station capable of logging and displaying in-flight telemetry,
177 aiding rocket recovery, then processing and archiving flight
178 data for analysis and review.
181 For a slightly more portable ground station experience that also
182 provides direct rocket recovery support, TeleBT offers flight
183 monitoring and data logging using a Bluetooth™ connection between
184 the receiver and an Android device that has the AltosDroid
185 application installed from the Google Play store.
188 More products will be added to the Altus Metrum family over time, and
189 we currently envision that this will be a single, comprehensive manual
190 for the entire product family.
194 <title>Getting Started</title>
196 The first thing to do after you check the inventory of parts in your
197 “starter kit” is to charge the battery.
200 For TeleMetrum and TeleMega, the battery can be charged by plugging it into the
201 corresponding socket of the device and then using the USB
202 cable to plug the flight computer into your computer's USB socket. The
203 on-board circuitry will charge the battery whenever it is plugged
204 in, because the on-off switch does NOT control the
208 On TeleMetrum v1 boards, when the GPS chip is initially
209 searching for satellites, TeleMetrum will consume more current
210 than it pulls from the USB port, so the battery must be
211 attached in order to get satellite lock. Once GPS is locked,
212 the current consumption goes back down enough to enable charging
213 while running. So it's a good idea to fully charge the battery
214 as your first item of business so there is no issue getting and
215 maintaining satellite lock. The yellow charge indicator led
216 will go out when the battery is nearly full and the charger goes
217 to trickle charge. It can take several hours to fully recharge a
218 deeply discharged battery.
221 TeleMetrum v2.0 and TeleMega use a higher power battery charger,
222 allowing them to charge the battery while running the board at
223 maximum power. When the battery is charging, or when the board
224 is consuming a lot of power, the red LED will be lit. When the
225 battery is fully charged, the green LED will be lit. When the
226 battery is damaged or missing, both LEDs will be lit, which
230 The Lithium Polymer TeleMini and EasyMini battery can be charged by
231 disconnecting it from the board and plugging it into a
232 standalone battery charger such as the LipoCharger product
233 included in TeleMini Starter Kits, and connecting that via a USB
234 cable to a laptop or other USB power source.
237 You can also choose to use another battery with TeleMini v2.0
238 and EasyMini, anything supplying between 4 and 12 volts should
239 work fine (like a standard 9V battery), but if you are planning
240 to fire pyro charges, ground testing is required to verify that
241 the battery supplies enough current to fire your chosen e-matches.
244 The other active device in the starter kit is the TeleDongle USB to
245 RF interface. If you plug it in to your Mac or Linux computer it should
246 “just work”, showing up as a serial port device. Windows systems need
247 driver information that is part of the AltOS download to know that the
248 existing USB modem driver will work. We therefore recommend installing
249 our software before plugging in TeleDongle if you are using a Windows
250 computer. If you are using an older version of Linux and are having
251 problems, try moving to a fresher kernel (2.6.33 or newer).
254 Next you should obtain and install the AltOS software. The AltOS
255 distribution includes the AltosUI ground station program, current
257 images for all of the hardware, and a number of standalone
258 utilities that are rarely needed. Pre-built binary packages are
259 available for Linux, Microsoft Windows, and recent MacOSX
260 versions. Full source code and build instructions are also
261 available. The latest version may always be downloaded from
262 <ulink url="http://altusmetrum.org/AltOS"/>.
265 If you're using a TeleBT instead of the TeleDongle, you'll want to
266 install the AltosDroid application from the Google Play store on an
267 Android device. You don't need a data plan to use AltosDroid, but
268 without network access, the Map view will be less useful as it
269 won't contain any map data. You can also use TeleBT connected
270 over USB with your laptop computer; it acts exactly like a
271 TeleDongle. Anywhere this manual talks about TeleDongle, you can
272 also read that as 'and TeleBT when connected via USB'.
276 <title>Handling Precautions</title>
278 All Altus Metrum products are sophisticated electronic devices.
279 When handled gently and properly installed in an air-frame, they
280 will deliver impressive results. However, as with all electronic
281 devices, there are some precautions you must take.
284 The Lithium Polymer rechargeable batteries have an
285 extraordinary power density. This is great because we can fly with
286 much less battery mass than if we used alkaline batteries or previous
287 generation rechargeable batteries... but if they are punctured
288 or their leads are allowed to short, they can and will release their
290 Thus we recommend that you take some care when handling our batteries
291 and consider giving them some extra protection in your air-frame. We
292 often wrap them in suitable scraps of closed-cell packing foam before
293 strapping them down, for example.
296 The barometric sensors used on all of our flight computers are
297 sensitive to sunlight. In normal mounting situations, the baro sensor
298 and all of the other surface mount components
299 are “down” towards whatever the underlying mounting surface is, so
300 this is not normally a problem. Please consider this when designing an
301 installation in an air-frame with a see-through plastic payload bay. It
302 is particularly important to
303 consider this with TeleMini v1.0, both because the baro sensor is on the
304 “top” of the board, and because many model rockets with payload bays
305 use clear plastic for the payload bay! Replacing these with an opaque
306 cardboard tube, painting them, or wrapping them with a layer of masking
307 tape are all reasonable approaches to keep the sensor out of direct
311 The barometric sensor sampling port must be able to “breathe”,
312 both by not being covered by foam or tape or other materials that might
313 directly block the hole on the top of the sensor, and also by having a
314 suitable static vent to outside air.
317 As with all other rocketry electronics, Altus Metrum altimeters must
318 be protected from exposure to corrosive motor exhaust and ejection
323 <title>Altus Metrum Hardware</title>
325 <title>Overview</title>
327 Here's the full set of Altus Metrum products, both in
328 production and retired.
331 <title>Altus Metrum Electronics</title>
332 <?dbfo keep-together="always"?>
333 <tgroup cols='8' align='center' colsep='1' rowsep='1'>
334 <colspec align='center' colwidth='*' colname='Device'/>
335 <colspec align='center' colwidth='*' colname='Barometer'/>
336 <colspec align='center' colwidth='*' colname='Z-axis accelerometer'/>
337 <colspec align='center' colwidth='*' colname='GPS'/>
338 <colspec align='center' colwidth='*' colname='3D sensors'/>
339 <colspec align='center' colwidth='*' colname='Storage'/>
340 <colspec align='center' colwidth='*' colname='RF'/>
341 <colspec align='center' colwidth='*' colname='Battery'/>
344 <entry align='center'>Device</entry>
345 <entry align='center'>Barometer</entry>
346 <entry align='center'>Z-axis accelerometer</entry>
347 <entry align='center'>GPS</entry>
348 <entry align='center'>3D sensors</entry>
349 <entry align='center'>Storage</entry>
350 <entry align='center'>RF Output</entry>
351 <entry align='center'>Battery</entry>
356 <entry>TeleMetrum v1.0</entry>
357 <entry><para>MP3H6115 10km (33k')</para></entry>
358 <entry><para>MMA2202 50g</para></entry>
359 <entry>SkyTraq</entry>
366 <entry>TeleMetrum v1.1</entry>
367 <entry><para>MP3H6115 10km (33k')</para></entry>
368 <entry><para>MMA2202 50g</para></entry>
369 <entry>SkyTraq</entry>
376 <entry>TeleMetrum v1.2</entry>
377 <entry><para>MP3H6115 10km (33k')</para></entry>
378 <entry><para>ADXL78 70g</para></entry>
379 <entry>SkyTraq</entry>
386 <entry>TeleMetrum v2.0</entry>
387 <entry><para>MS5607 30km (100k')</para></entry>
388 <entry><para>MMA6555 102g</para></entry>
389 <entry>uBlox Max-7Q</entry>
396 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
397 <entry><para>MP3H6115 10km (33k')</para></entry>
406 <entry>TeleMini <?linebreak?>v2.0</entry>
407 <entry><para>MS5607 30km (100k')</para></entry>
413 <entry>3.7-12V</entry>
416 <entry>EasyMini <?linebreak?>v1.0</entry>
417 <entry><para>MS5607 30km (100k')</para></entry>
423 <entry>3.7-12V</entry>
426 <entry>TeleMega <?linebreak?>v1.0</entry>
427 <entry><para>MS5607 30km (100k')</para></entry>
428 <entry><para>MMA6555 102g</para></entry>
429 <entry>uBlox Max-7Q</entry>
430 <entry><para>MPU6000 HMC5883</para></entry>
439 <title>Altus Metrum Boards</title>
440 <?dbfo keep-together="always"?>
441 <tgroup cols='6' align='center' colsep='1' rowsep='1'>
442 <colspec align='center' colwidth='*' colname='Device'/>
443 <colspec align='center' colwidth='*' colname='Connectors'/>
444 <colspec align='center' colwidth='*' colname='Screw Terminals'/>
445 <colspec align='center' colwidth='*' colname='Width'/>
446 <colspec align='center' colwidth='*' colname='Length'/>
447 <colspec align='center' colwidth='*' colname='Tube Size'/>
450 <entry align='center'>Device</entry>
451 <entry align='center'>Connectors</entry>
452 <entry align='center'>Screw Terminals</entry>
453 <entry align='center'>Width</entry>
454 <entry align='center'>Length</entry>
455 <entry align='center'>Tube Size</entry>
460 <entry>TeleMetrum</entry>
464 Companion<?linebreak?>
468 <entry><para>Apogee pyro <?linebreak?>Main pyro <?linebreak?>Switch</para></entry>
469 <entry>1 inch (2.54cm)</entry>
470 <entry>2 ¾ inch (6.99cm)</entry>
471 <entry>29mm coupler</entry>
474 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
481 Apogee pyro <?linebreak?>
484 <entry>½ inch (1.27cm)</entry>
485 <entry>1½ inch (3.81cm)</entry>
486 <entry>18mm coupler</entry>
489 <entry>TeleMini <?linebreak?>v2.0</entry>
497 Apogee pyro <?linebreak?>
498 Main pyro <?linebreak?>
499 Battery <?linebreak?>
502 <entry>0.8 inch (2.03cm)</entry>
503 <entry>1½ inch (3.81cm)</entry>
504 <entry>24mm coupler</entry>
507 <entry>EasyMini</entry>
514 Apogee pyro <?linebreak?>
515 Main pyro <?linebreak?>
516 Battery <?linebreak?>
519 <entry>0.8 inch (2.03cm)</entry>
520 <entry>1½ inch (3.81cm)</entry>
521 <entry>24mm coupler</entry>
524 <entry>TeleMega</entry>
528 Companion<?linebreak?>
533 Apogee pyro <?linebreak?>
534 Main pyro<?linebreak?>
535 Pyro A-D<?linebreak?>
539 <entry>1¼ inch (3.18cm)</entry>
540 <entry>3¼ inch (8.26cm)</entry>
541 <entry>38mm coupler</entry>
548 <title>TeleMetrum</title>
552 <imagedata fileref="telemetrum-v1.1-thside.jpg" width="5.5in" scalefit="1"/>
557 TeleMetrum is a 1 inch by 2¾ inch circuit board. It was designed to
558 fit inside coupler for 29mm air-frame tubing, but using it in a tube that
559 small in diameter may require some creativity in mounting and wiring
560 to succeed! The presence of an accelerometer means TeleMetrum should
561 be aligned along the flight axis of the airframe, and by default the ¼
562 wave UHF wire antenna should be on the nose-cone end of the board. The
563 antenna wire is about 7 inches long, and wiring for a power switch and
564 the e-matches for apogee and main ejection charges depart from the
565 fin can end of the board, meaning an ideal “simple” avionics
566 bay for TeleMetrum should have at least 10 inches of interior length.
570 <title>TeleMini</title>
574 <imagedata fileref="telemini-v1-top.jpg" width="5.5in" scalefit="1"/>
579 TeleMini v1.0 is ½ inches by 1½ inches. It was
580 designed to fit inside an 18mm air-frame tube, but using it in
581 a tube that small in diameter may require some creativity in
582 mounting and wiring to succeed! Since there is no
583 accelerometer, TeleMini can be mounted in any convenient
584 orientation. The default ¼ wave UHF wire antenna attached to
585 the center of one end of the board is about 7 inches long. Two
586 wires for the power switch are connected to holes in the
587 middle of the board. Screw terminals for the e-matches for
588 apogee and main ejection charges depart from the other end of
589 the board, meaning an ideal “simple” avionics bay for TeleMini
590 should have at least 9 inches of interior length.
595 <imagedata fileref="telemini-v2-top.jpg" width="5.5in" scalefit="1"/>
600 TeleMini v2.0 is 0.8 inches by 1½ inches. It adds more
601 on-board data logging memory, a built-in USB connector and
602 screw terminals for the battery and power switch. The larger
603 board fits in a 24mm coupler. There's also a battery connector
604 for a LiPo battery if you want to use one of those.
608 <title>EasyMini</title>
612 <imagedata fileref="easymini-top.jpg" width="5.5in" scalefit="1"/>
617 EasyMini is built on a 0.8 inch by 1½ inch circuit board. It's
618 designed to fit in a 24mm coupler tube. The connectors and
619 screw terminals match TeleMini v2.0, so you can easily swap between
620 EasyMini and TeleMini.
624 <title>TeleMega</title>
628 <imagedata fileref="telemega-v1.0-top.jpg" width="5.5in" scalefit="1"/>
633 TeleMega is a 1¼ inch by 3¼ inch circuit board. It was
634 designed to easily fit in a 38mm coupler. Like TeleMetrum,
635 TeleMega has an accelerometer and so it must be mounted so that
636 the board is aligned with the flight axis. It can be mounted
637 either antenna up or down.
641 <title>Flight Data Recording</title>
643 Each flight computer logs data at 100 samples per second
644 during ascent and 10 samples per second during descent, except
645 for TeleMini v1.0, which records ascent at 10 samples per
646 second and descent at 1 sample per second. Data are logged to
647 an on-board flash memory part, which can be partitioned into
648 several equal-sized blocks, one for each flight.
651 <title>Data Storage on Altus Metrum altimeters</title>
652 <?dbfo keep-together="always"?>
653 <tgroup cols='4' align='center' colsep='1' rowsep='1'>
654 <colspec align='center' colwidth='*' colname='Device'/>
655 <colspec align='center' colwidth='*' colname='Bytes per sample'/>
656 <colspec align='center' colwidth='*' colname='Total storage'/>
657 <colspec align='center' colwidth='*' colname='Minutes of
661 <entry align='center'>Device</entry>
662 <entry align='center'>Bytes per Sample</entry>
663 <entry align='center'>Total Storage</entry>
664 <entry align='center'>Minutes at Full Rate</entry>
669 <entry>TeleMetrum v1.0</entry>
675 <entry>TeleMetrum v1.1 v1.2</entry>
681 <entry>TeleMetrum v2.0</entry>
687 <entry>TeleMini v1.0</entry>
693 <entry>TeleMini v2.0</entry>
699 <entry>EasyMini</entry>
705 <entry>TeleMega</entry>
714 The on-board flash is partitioned into separate flight logs,
715 each of a fixed maximum size. Increase the maximum size of
716 each log and you reduce the number of flights that can be
717 stored. Decrease the size and you can store more flights.
720 Configuration data is also stored in the flash memory on
721 TeleMetrum v1.x, TeleMini and EasyMini. This consumes 64kB
722 of flash space. This configuration space is not available
723 for storing flight log data. TeleMetrum v2.0 and TeleMega
724 store configuration data in a bit of eeprom available within
725 the processor chip, leaving that space available in flash for
729 To compute the amount of space needed for a single flight, you
730 can multiply the expected ascent time (in seconds) by 100
731 times bytes-per-sample, multiply the expected descent time (in
732 seconds) by 10 times the bytes per sample and add the two
733 together. That will slightly under-estimate the storage (in
734 bytes) needed for the flight. For instance, a TeleMetrum v2.0 flight spending
735 20 seconds in ascent and 150 seconds in descent will take
736 about (20 * 1600) + (150 * 160) = 56000 bytes of storage. You
737 could store dozens of these flights in the on-board flash.
740 The default size allows for several flights on each flight
741 computer, except for TeleMini v1.0, which only holds data for a
742 single flight. You can adjust the size.
745 Altus Metrum flight computers will not overwrite existing
746 flight data, so be sure to download flight data and erase it
747 from the flight computer before it fills up. The flight
748 computer will still successfully control the flight even if it
749 cannot log data, so the only thing you will lose is the data.
753 <title>Installation</title>
755 A typical installation involves attaching
756 only a suitable battery, a single pole switch for
757 power on/off, and two pairs of wires connecting e-matches for the
758 apogee and main ejection charges. All Altus Metrum products are
759 designed for use with single-cell batteries with 3.7 volts
760 nominal. TeleMini v2.0 and EasyMini may also be used with other
761 batteries as long as they supply between 4 and 12 volts.
764 The battery connectors are a standard 2-pin JST connector and
765 match batteries sold by Spark Fun. These batteries are
766 single-cell Lithium Polymer batteries that nominally provide 3.7
767 volts. Other vendors sell similar batteries for RC aircraft
768 using mating connectors, however the polarity for those is
769 generally reversed from the batteries used by Altus Metrum
770 products. In particular, the Tenergy batteries supplied for use
771 in Featherweight flight computers are not compatible with Altus
772 Metrum flight computers or battery chargers. <emphasis>Check
773 polarity and voltage before connecting any battery not purchased
774 from Altus Metrum or Spark Fun.</emphasis>
777 By default, we use the unregulated output of the battery directly
778 to fire ejection charges. This works marvelously with standard
779 low-current e-matches like the J-Tek from MJG Technologies, and with
780 Quest Q2G2 igniters. However, if you want or need to use a separate
781 pyro battery, check out the “External Pyro Battery” section in this
782 manual for instructions on how to wire that up. The altimeters are
783 designed to work with an external pyro battery of no more than 15 volts.
787 Ejection charges are wired directly to the screw terminal block
788 at the aft end of the altimeter. You'll need a very small straight
789 blade screwdriver for these screws, such as you might find in a
790 jeweler's screwdriver set.
793 Except for TeleMini v1.0, the flight computers also use the
794 screw terminal block for the power switch leads. On TeleMini v1.0,
795 the power switch leads are soldered directly to the board and
796 can be connected directly to a switch.
799 For most air-frames, the integrated antennas are more than
800 adequate. However, if you are installing in a carbon-fiber or
801 metal electronics bay which is opaque to RF signals, you may need to
802 use off-board external antennas instead. In this case, you can
803 replace the stock UHF antenna wire with an edge-launched SMA connector,
804 and, on TeleMetrum v1, you can unplug the integrated GPS
805 antenna and select an appropriate off-board GPS antenna with
806 cable terminating in a U.FL connector.
811 <title>System Operation</title>
813 <title>Firmware Modes </title>
815 The AltOS firmware build for the altimeters has two
816 fundamental modes, “idle” and “flight”. Which of these modes
817 the firmware operates in is determined at start up time. For
818 TeleMetrum and TeleMega, which have accelerometers, the mode is
819 controlled by the orientation of the
820 rocket (well, actually the board, of course...) at the time
821 power is switched on. If the rocket is “nose up”, then
822 the flight computer assumes it's on a rail or rod being prepared for
823 launch, so the firmware chooses flight mode. However, if the
824 rocket is more or less horizontal, the firmware instead enters
825 idle mode. Since TeleMini v2.0 and EasyMini don't have an
826 accelerometer we can use to determine orientation, “idle” mode
827 is selected if the board is connected via USB to a computer,
828 otherwise the board enters “flight” mode. TeleMini v1.0
829 selects “idle” mode if it receives a command packet within the
830 first five seconds of operation.
833 At power on, you will hear three beeps or see three flashes
834 (“S” in Morse code for start up) and then a pause while
835 the altimeter completes initialization and self test, and decides
836 which mode to enter next.
839 Here's a short summary of all of the modes and the beeping (or
840 flashing, in the case of TeleMini v1) that accompanies each
841 mode. In the description of the beeping pattern, “dit” means a
842 short beep while "dah" means a long beep (three times as
843 long). “Brap” means a long dissonant tone.
845 <title>AltOS Modes</title>
846 <?dbfo keep-together="always"?>
847 <tgroup cols='4' align='center' colsep='1' rowsep='1'>
848 <colspec align='center' colwidth='*' colname='Mode Name'/>
849 <colspec align='center' colwidth='*' colname='Letter'/>
850 <colspec align='center' colwidth='*' colname='Beeps'/>
851 <colspec align='center' colwidth='*' colname='Description'/>
854 <entry>Mode Name</entry>
855 <entry>Abbreviation</entry>
857 <entry>Description</entry>
862 <entry>Startup</entry>
864 <entry>dit dit dit</entry>
867 Calibrating sensors, detecting orientation.
874 <entry>dit dit</entry>
877 Ready to accept commands over USB or radio link.
884 <entry>dit dah dah dit</entry>
887 Waiting for launch. Not listening for commands.
894 <entry>dah dit dit dit</entry>
897 Accelerating upwards.
904 <entry>dit dit dah dit</entry>
907 Decellerating, but moving faster than 200m/s.
914 <entry>dah dit dah dit</entry>
917 Decellerating, moving slower than 200m/s
922 <entry>Drogue</entry>
924 <entry>dah dit dit</entry>
927 Descending after apogee. Above main height.
934 <entry>dah dah</entry>
937 Descending. Below main height.
942 <entry>Landed</entry>
944 <entry>dit dah dit dit</entry>
947 Stable altitude for at least ten seconds.
952 <entry>Sensor error</entry>
954 <entry>dah dit dit dah</entry>
957 Error detected during sensor calibration.
966 In flight or “pad” mode, the altimeter engages the flight
967 state machine, goes into transmit-only mode to send telemetry,
968 and waits for launch to be detected. Flight mode is indicated
969 by an “di-dah-dah-dit” (“P” for pad) on the beeper or lights,
970 followed by beeps or flashes indicating the state of the
971 pyrotechnic igniter continuity. One beep/flash indicates
972 apogee continuity, two beeps/flashes indicate main continuity,
973 three beeps/flashes indicate both apogee and main continuity,
974 and one longer “brap” sound which is made by rapidly
975 alternating between two tones indicates no continuity. For a
976 dual deploy flight, make sure you're getting three beeps or
977 flashes before launching! For apogee-only or motor eject
978 flights, do what makes sense.
981 If idle mode is entered, you will hear an audible “di-dit” or
982 see two short flashes (“I” for idle), and the flight state
983 machine is disengaged, thus no ejection charges will fire.
984 The altimeters also listen for the radio link when in idle
985 mode for requests sent via TeleDongle. Commands can be issued
986 in idle mode over either USB or the radio link
987 equivalently. TeleMini v1.0 only has the radio link. Idle
988 mode is useful for configuring the altimeter, for extracting
989 data from the on-board storage chip after flight, and for
990 ground testing pyro charges.
993 In “Idle” and “Pad” modes, once the mode indication
994 beeps/flashes and continuity indication has been sent, if
995 there is no space available to log the flight in on-board
996 memory, the flight computer will emit a warbling tone (much
997 slower than the “no continuity tone”)
1000 Here's a summary of all of the “pad” and “idle” mode indications.
1002 <title>Pad/Idle Indications</title>
1003 <?dbfo keep-together="always"?>
1004 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
1005 <colspec align='center' colwidth='*' colname='Name'/>
1006 <colspec align='center' colwidth='*' colname='Beeps'/>
1007 <colspec align='center' colwidth='*' colname='Description'/>
1011 <entry>Beeps</entry>
1012 <entry>Description</entry>
1017 <entry>Neither</entry>
1021 No continuity detected on either apogee or main
1027 <entry>Apogee</entry>
1031 Continuity detected only on apogee igniter.
1037 <entry>dit dit</entry>
1040 Continuity detected only on main igniter.
1046 <entry>dit dit dit</entry>
1049 Continuity detected on both igniters.
1054 <entry>Storage Full</entry>
1055 <entry>warble</entry>
1058 On-board data logging storage is full. This will
1059 not prevent the flight computer from safely
1060 controlling the flight or transmitting telemetry
1061 signals, but no record of the flight will be
1062 stored in on-board flash.
1071 Once landed, the flight computer will signal that by emitting
1072 the “Landed” sound described above, after which it will beep
1073 out the apogee height (in meters). Each digit is represented
1074 by a sequence of short “dit” beeps, with a pause between
1075 digits. A zero digit is represented with one long “dah”
1076 beep. The flight computer will continue to report landed mode
1077 and beep out the maximum height until turned off.
1080 One “neat trick” of particular value when TeleMetrum or TeleMega are used with
1081 very large air-frames, is that you can power the board up while the
1082 rocket is horizontal, such that it comes up in idle mode. Then you can
1083 raise the air-frame to launch position, and issue a 'reset' command
1084 via TeleDongle over the radio link to cause the altimeter to reboot and
1085 come up in flight mode. This is much safer than standing on the top
1086 step of a rickety step-ladder or hanging off the side of a launch
1087 tower with a screw-driver trying to turn on your avionics before
1088 installing igniters!
1091 TeleMini v1.0 is configured solely via the radio link. Of course, that
1092 means you need to know the TeleMini radio configuration values
1093 or you won't be able to communicate with it. For situations
1094 when you don't have the radio configuration values, TeleMini v1.0
1095 offers an 'emergency recovery' mode. In this mode, TeleMini is
1096 configured as follows:
1100 Sets the radio frequency to 434.550MHz
1105 Sets the radio calibration back to the factory value.
1110 Sets the callsign to N0CALL
1115 Does not go to 'pad' mode after five seconds.
1121 To get into 'emergency recovery' mode, first find the row of
1122 four small holes opposite the switch wiring. Using a short
1123 piece of small gauge wire, connect the outer two holes
1124 together, then power TeleMini up. Once the red LED is lit,
1125 disconnect the wire and the board should signal that it's in
1126 'idle' mode after the initial five second startup period.
1132 TeleMetrum and TeleMega include a complete GPS receiver. A
1133 complete explanation of how GPS works is beyond the scope of
1134 this manual, but the bottom line is that the GPS receiver
1135 needs to lock onto at least four satellites to obtain a solid
1136 3 dimensional position fix and know what time it is.
1139 The flight computers provide backup power to the GPS chip any time a
1140 battery is connected. This allows the receiver to “warm start” on
1141 the launch rail much faster than if every power-on were a GPS
1142 “cold start”. In typical operations, powering up
1143 on the flight line in idle mode while performing final air-frame
1144 preparation will be sufficient to allow the GPS receiver to cold
1145 start and acquire lock. Then the board can be powered down during
1146 RSO review and installation on a launch rod or rail. When the board
1147 is turned back on, the GPS system should lock very quickly, typically
1148 long before igniter installation and return to the flight line are
1153 <title>Controlling An Altimeter Over The Radio Link</title>
1155 One of the unique features of the Altus Metrum system is the
1156 ability to create a two way command link between TeleDongle
1157 and an altimeter using the digital radio transceivers
1158 built into each device. This allows you to interact with the
1159 altimeter from afar, as if it were directly connected to the
1163 Any operation which can be performed with a flight computer can
1164 either be done with the device directly connected to the
1165 computer via the USB cable, or through the radio
1166 link. TeleMini v1.0 doesn't provide a USB connector and so it is
1167 always communicated with over radio. Select the appropriate
1168 TeleDongle device when the list of devices is presented and
1169 AltosUI will interact with an altimeter over the radio link.
1172 One oddity in the current interface is how AltosUI selects the
1173 frequency for radio communications. Instead of providing
1174 an interface to specifically configure the frequency, it uses
1175 whatever frequency was most recently selected for the target
1176 TeleDongle device in Monitor Flight mode. If you haven't ever
1177 used that mode with the TeleDongle in question, select the
1178 Monitor Flight button from the top level UI, and pick the
1179 appropriate TeleDongle device. Once the flight monitoring
1180 window is open, select the desired frequency and then close it
1181 down again. All radio communications will now use that frequency.
1186 Save Flight Data—Recover flight data from the rocket without
1192 Configure altimeter apogee delays, main deploy heights
1193 and additional pyro event conditions
1194 to respond to changing launch conditions. You can also
1195 'reboot' the altimeter. Use this to remotely enable the
1196 flight computer by turning TeleMetrum or TeleMega on in “idle” mode,
1197 then once the air-frame is oriented for launch, you can
1198 reboot the altimeter and have it restart in pad mode
1199 without having to climb the scary ladder.
1204 Fire Igniters—Test your deployment charges without snaking
1205 wires out through holes in the air-frame. Simply assemble the
1206 rocket as if for flight with the apogee and main charges
1207 loaded, then remotely command the altimeter to fire the
1213 Operation over the radio link for configuring an altimeter, ground
1214 testing igniters, and so forth uses the same RF frequencies as flight
1215 telemetry. To configure the desired TeleDongle frequency, select
1216 the monitor flight tab, then use the frequency selector and
1217 close the window before performing other desired radio operations.
1220 The flight computers only enable radio commanding in 'idle' mode.
1221 TeleMetrum and TeleMega use the accelerometer to detect which orientation they
1222 start up in, so make sure you have the flight computer lying horizontally when you turn
1223 it on. Otherwise, it will start in 'pad' mode ready for
1224 flight, and will not be listening for command packets from TeleDongle.
1227 TeleMini listens for a command packet for five seconds after
1228 first being turned on, if it doesn't hear anything, it enters
1229 'pad' mode, ready for flight and will no longer listen for
1230 command packets. The easiest way to connect to TeleMini is to
1231 initiate the command and select the TeleDongle device. At this
1232 point, the TeleDongle will be attempting to communicate with
1233 the TeleMini. Now turn TeleMini on, and it should immediately
1234 start communicating with the TeleDongle and the desired
1235 operation can be performed.
1238 You can monitor the operation of the radio link by watching the
1239 lights on the devices. The red LED will flash each time a packet
1240 is transmitted, while the green LED will light up on TeleDongle when
1241 it is waiting to receive a packet from the altimeter.
1245 <title>Ground Testing </title>
1247 An important aspect of preparing a rocket using electronic deployment
1248 for flight is ground testing the recovery system. Thanks
1249 to the bi-directional radio link central to the Altus Metrum system,
1250 this can be accomplished in a TeleMega, TeleMetrum or TeleMini equipped rocket
1251 with less work than you may be accustomed to with other systems. It
1255 Just prep the rocket for flight, then power up the altimeter
1256 in “idle” mode (placing air-frame horizontal for TeleMetrum or TeleMega, or
1257 selecting the Configure Altimeter tab for TeleMini). This will cause
1258 the firmware to go into “idle” mode, in which the normal flight
1259 state machine is disabled and charges will not fire without
1260 manual command. You can now command the altimeter to fire the apogee
1261 or main charges from a safe distance using your computer and
1262 TeleDongle and the Fire Igniter tab to complete ejection testing.
1266 <title>Radio Link </title>
1268 Our flight computers all incorporate an RF transceiver, but
1269 it's not a full duplex system... each end can only be transmitting or
1270 receiving at any given moment. So we had to decide how to manage the
1274 By design, the altimeter firmware listens for the radio link when
1275 it's in “idle mode”, which
1276 allows us to use the radio link to configure the rocket, do things like
1277 ejection tests, and extract data after a flight without having to
1278 crack open the air-frame. However, when the board is in “flight
1279 mode”, the altimeter only
1280 transmits and doesn't listen at all. That's because we want to put
1281 ultimate priority on event detection and getting telemetry out of
1283 the radio in case the rocket crashes and we aren't able to extract
1287 We don't generally use a 'normal packet radio' mode like APRS
1288 because they're just too inefficient. The GFSK modulation we
1289 use is FSK with the base-band pulses passed through a Gaussian
1290 filter before they go into the modulator to limit the
1291 transmitted bandwidth. When combined with forward error
1292 correction and interleaving, this allows us to have a very
1293 robust 19.2 kilobit data link with only 10-40 milliwatts of
1294 transmit power, a whip antenna in the rocket, and a hand-held
1295 Yagi on the ground. We've had flights to above 21k feet AGL
1296 with great reception, and calculations suggest we should be
1297 good to well over 40k feet AGL with a 5-element yagi on the
1298 ground with our 10mW units and over 100k feet AGL with the
1299 40mW devices. We hope to fly boards to higher altitudes over
1300 time, and would of course appreciate customer feedback on
1301 performance in higher altitude flights!
1304 TeleMetrum v2.0 and TeleMega can send APRS if desired, and the
1305 interval between APRS packets can be configured. As each APRS
1306 packet takes a full second to transmit, we recommend an
1307 interval of at least 5 seconds to avoid consuming too much
1308 battery power or radio channel bandwidth.
1312 <title>Configurable Parameters</title>
1314 Configuring an Altus Metrum altimeter for flight is very
1315 simple. Even on our baro-only TeleMini and EasyMini boards, the use of a Kalman
1316 filter means there is no need to set a “mach delay”. The few
1317 configurable parameters can all be set using AltosUI over USB or
1318 or radio link via TeleDongle.
1321 <title>Radio Frequency</title>
1323 Altus Metrum boards support radio frequencies in the 70cm
1324 band. By default, the configuration interface provides a
1325 list of 10 “standard” frequencies in 100kHz channels starting at
1326 434.550MHz. However, the firmware supports use of
1327 any 50kHz multiple within the 70cm band. At any given
1328 launch, we highly recommend coordinating when and by whom each
1329 frequency will be used to avoid interference. And of course, both
1330 altimeter and TeleDongle must be configured to the same
1331 frequency to successfully communicate with each other.
1335 <title>Apogee Delay</title>
1337 Apogee delay is the number of seconds after the altimeter detects flight
1338 apogee that the drogue charge should be fired. In most cases, this
1339 should be left at the default of 0. However, if you are flying
1340 redundant electronics such as for an L3 certification, you may wish
1341 to set one of your altimeters to a positive delay so that both
1342 primary and backup pyrotechnic charges do not fire simultaneously.
1345 The Altus Metrum apogee detection algorithm fires exactly at
1346 apogee. If you are also flying an altimeter like the
1347 PerfectFlite MAWD, which only supports selecting 0 or 1
1348 seconds of apogee delay, you may wish to set the MAWD to 0
1349 seconds delay and set the TeleMetrum to fire your backup 2
1350 or 3 seconds later to avoid any chance of both charges
1351 firing simultaneously. We've flown several air-frames this
1352 way quite happily, including Keith's successful L3 cert.
1356 <title>Main Deployment Altitude</title>
1358 By default, the altimeter will fire the main deployment charge at an
1359 elevation of 250 meters (about 820 feet) above ground. We think this
1360 is a good elevation for most air-frames, but feel free to change this
1361 to suit. In particular, if you are flying two altimeters, you may
1363 deployment elevation for the backup altimeter to be something lower
1364 than the primary so that both pyrotechnic charges don't fire
1369 <title>Maximum Flight Log</title>
1371 Changing this value will set the maximum amount of flight
1372 log storage that an individual flight will use. The
1373 available storage is divided into as many flights of the
1374 specified size as can fit in the available space. You can
1375 download and erase individual flight logs. If you fill up
1376 the available storage, future flights will not get logged
1377 until you erase some of the stored ones.
1380 Even though our flight computers (except TeleMini v1.0) can store
1381 multiple flights, we strongly recommend downloading and saving
1382 flight data after each flight.
1386 <title>Ignite Mode</title>
1388 Instead of firing one charge at apogee and another charge at
1389 a fixed height above the ground, you can configure the
1390 altimeter to fire both at apogee or both during
1391 descent. This was added to support an airframe Bdale designed that
1392 had two altimeters, one in the fin can and one in the nose.
1395 Providing the ability to use both igniters for apogee or
1396 main allows some level of redundancy without needing two
1397 flight computers. In Redundant Apogee or Redundant Main
1398 mode, the two charges will be fired two seconds apart.
1402 <title>Pad Orientation</title>
1404 TeleMetrum and TeleMega measure acceleration along the axis
1405 of the board. Which way the board is oriented affects the
1406 sign of the acceleration value. Instead of trying to guess
1407 which way the board is mounted in the air frame, the
1408 altimeter must be explicitly configured for either Antenna
1409 Up or Antenna Down. The default, Antenna Up, expects the end
1410 of the board connected to the 70cm antenna to be nearest the
1411 nose of the rocket, with the end containing the screw
1412 terminals nearest the tail.
1416 <title>Configurable Pyro Channels</title>
1418 In addition to the usual Apogee and Main pyro channels,
1419 TeleMega has four additional channels that can be configured
1420 to activate when various flight conditions are
1421 satisfied. You can select as many conditions as necessary;
1422 all of them must be met in order to activate the
1423 channel. The conditions available are:
1428 Acceleration away from the ground. Select a value, and
1429 then choose whether acceleration should be above or
1430 below that value. Acceleration is positive upwards, so
1431 accelerating towards the ground would produce negative
1432 numbers. Acceleration during descent is noisy and
1433 inaccurate, so be careful when using it during these
1434 phases of the flight.
1439 Vertical speed. Select a value, and then choose whether
1440 vertical speed should be above or below that
1441 value. Speed is positive upwards, so moving towards the
1442 ground would produce negative numbers. Speed during
1443 descent is a bit noisy and so be careful when using it
1444 during these phases of the flight.
1449 Height. Select a value, and then choose whether the
1450 height above the launch pad should be above or below
1456 Orientation. TeleMega contains a 3-axis gyroscope and
1457 accelerometer which is used to measure the current
1458 angle. Note that this angle is not the change in angle
1459 from the launch pad, but rather absolute relative to
1460 gravity; the 3-axis accelerometer is used to compute the
1461 angle of the rocket on the launch pad and initialize the
1462 system. Because this value is computed by integrating
1463 rate gyros, it gets progressively less accurate as the
1464 flight goes on. It should have an accumulated error of
1465 less than 0.2°/second (after 10 seconds of flight, the
1466 error should be less than 2°).
1469 The usual use of the orientation configuration is to
1470 ensure that the rocket is traveling mostly upwards when
1471 deciding whether to ignite air starts or additional
1472 stages. For that, choose a reasonable maximum angle
1473 (like 20°) and set the motor igniter to require an angle
1474 of less than that value.
1479 Flight Time. Time since boost was detected. Select a
1480 value and choose whether to activate the pyro channel
1481 before or after that amount of time.
1486 Ascending. A simple test saying whether the rocket is
1487 going up or not. This is exactly equivalent to testing
1488 whether the speed is > 0.
1493 Descending. A simple test saying whether the rocket is
1494 going down or not. This is exactly equivalent to testing
1495 whether the speed is < 0.
1500 After Motor. The flight software counts each time the
1501 rocket starts accelerating (presumably due to a motor or
1502 motors igniting). Use this value to count ignitions for
1503 multi-staged or multi-airstart launches.
1508 Delay. This value doesn't perform any checks, instead it
1509 inserts a delay between the time when the other
1510 parameters become true and when the pyro channel is
1516 Flight State. The flight software tracks the flight
1517 through a sequence of states:
1521 Boost. The motor has lit and the rocket is
1522 accelerating upwards.
1527 Fast. The motor has burned out and the rocket is
1528 descellerating, but it is going faster than 200m/s.
1533 Coast. The rocket is still moving upwards and
1534 decelerating, but the speed is less than 200m/s.
1539 Drogue. The rocket has reached apogee and is heading
1540 back down, but is above the configured Main
1546 Main. The rocket is still descending, and is below
1552 Landed. The rocket is no longer moving.
1558 You can select a state to limit when the pyro channel
1559 may activate; note that the check is based on when the
1560 rocket transitions <emphasis>into</emphasis> the state, and so checking for
1561 “greater than Boost” means that the rocket is currently
1562 in boost or some later state.
1565 When a motor burns out, the rocket enters either Fast or
1566 Coast state (depending on how fast it is moving). If the
1567 computer detects upwards acceleration again, it will
1568 move back to Boost state.
1577 <title>AltosUI</title>
1581 <imagedata fileref="altosui.png" width="4.6in"/>
1586 The AltosUI program provides a graphical user interface for
1587 interacting with the Altus Metrum product family. AltosUI can
1588 monitor telemetry data, configure devices and many other
1589 tasks. The primary interface window provides a selection of
1590 buttons, one for each major activity in the system. This chapter
1591 is split into sections, each of which documents one of the tasks
1592 provided from the top-level toolbar.
1595 <title>Monitor Flight</title>
1596 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
1598 Selecting this item brings up a dialog box listing all of the
1599 connected TeleDongle devices. When you choose one of these,
1600 AltosUI will create a window to display telemetry data as
1601 received by the selected TeleDongle device.
1606 <imagedata fileref="device-selection.png" width="3.1in"/>
1611 All telemetry data received are automatically recorded in
1612 suitable log files. The name of the files includes the current
1613 date and rocket serial and flight numbers.
1616 The radio frequency being monitored by the TeleDongle device is
1617 displayed at the top of the window. You can configure the
1618 frequency by clicking on the frequency box and selecting the desired
1619 frequency. AltosUI remembers the last frequency selected for each
1620 TeleDongle and selects that automatically the next time you use
1624 Below the TeleDongle frequency selector, the window contains a few
1625 significant pieces of information about the altimeter providing
1626 the telemetry data stream:
1630 <para>The configured call-sign</para>
1633 <para>The device serial number</para>
1636 <para>The flight number. Each altimeter remembers how many
1642 The rocket flight state. Each flight passes through several
1643 states including Pad, Boost, Fast, Coast, Drogue, Main and
1649 The Received Signal Strength Indicator value. This lets
1650 you know how strong a signal TeleDongle is receiving. The
1651 radio inside TeleDongle operates down to about -99dBm;
1652 weaker signals may not be receivable. The packet link uses
1653 error detection and correction techniques which prevent
1654 incorrect data from being reported.
1659 The age of the displayed data, in seconds since the last
1660 successfully received telemetry packet. In normal operation
1661 this will stay in the low single digits. If the number starts
1662 counting up, then you are no longer receiving data over the radio
1663 link from the flight computer.
1668 Finally, the largest portion of the window contains a set of
1669 tabs, each of which contain some information about the rocket.
1670 They're arranged in 'flight order' so that as the flight
1671 progresses, the selected tab automatically switches to display
1672 data relevant to the current state of the flight. You can select
1673 other tabs at any time. The final 'table' tab displays all of
1674 the raw telemetry values in one place in a spreadsheet-like format.
1677 <title>Launch Pad</title>
1681 <imagedata fileref="launch-pad.png" width="5.5in"/>
1686 The 'Launch Pad' tab shows information used to decide when the
1687 rocket is ready for flight. The first elements include red/green
1688 indicators, if any of these is red, you'll want to evaluate
1689 whether the rocket is ready to launch:
1692 <term>Battery Voltage</term>
1695 This indicates whether the Li-Po battery powering the
1696 flight computer has sufficient charge to last for
1697 the duration of the flight. A value of more than
1698 3.8V is required for a 'GO' status.
1703 <term>Apogee Igniter Voltage</term>
1706 This indicates whether the apogee
1707 igniter has continuity. If the igniter has a low
1708 resistance, then the voltage measured here will be close
1709 to the Li-Po battery voltage. A value greater than 3.2V is
1710 required for a 'GO' status.
1715 <term>Main Igniter Voltage</term>
1718 This indicates whether the main
1719 igniter has continuity. If the igniter has a low
1720 resistance, then the voltage measured here will be close
1721 to the Li-Po battery voltage. A value greater than 3.2V is
1722 required for a 'GO' status.
1727 <term>On-board Data Logging</term>
1730 This indicates whether there is
1731 space remaining on-board to store flight data for the
1732 upcoming flight. If you've downloaded data, but failed
1733 to erase flights, there may not be any space
1734 left. Most of our flight computers can store multiple
1735 flights, depending on the configured maximum flight log
1736 size. TeleMini v1.0 stores only a single flight, so it
1738 downloaded and erased after each flight to capture
1739 data. This only affects on-board flight logging; the
1740 altimeter will still transmit telemetry and fire
1741 ejection charges at the proper times even if the flight
1742 data storage is full.
1747 <term>GPS Locked</term>
1750 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
1751 currently able to compute position information. GPS requires
1752 at least 4 satellites to compute an accurate position.
1757 <term>GPS Ready</term>
1760 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
1761 10 consecutive positions without losing lock. This ensures
1762 that the GPS receiver has reliable reception from the
1770 The Launchpad tab also shows the computed launch pad position
1771 and altitude, averaging many reported positions to improve the
1772 accuracy of the fix.
1776 <title>Ascent</title>
1780 <imagedata fileref="ascent.png" width="5.5in"/>
1785 This tab is shown during Boost, Fast and Coast
1786 phases. The information displayed here helps monitor the
1787 rocket as it heads towards apogee.
1790 The height, speed and acceleration are shown along with the
1791 maximum values for each of them. This allows you to quickly
1792 answer the most commonly asked questions you'll hear during
1796 The current latitude and longitude reported by the GPS are
1797 also shown. Note that under high acceleration, these values
1798 may not get updated as the GPS receiver loses position
1799 fix. Once the rocket starts coasting, the receiver should
1800 start reporting position again.
1803 Finally, the current igniter voltages are reported as in the
1804 Launch Pad tab. This can help diagnose deployment failures
1805 caused by wiring which comes loose under high acceleration.
1809 <title>Descent</title>
1813 <imagedata fileref="descent.png" width="5.5in"/>
1818 Once the rocket has reached apogee and (we hope) activated the
1819 apogee charge, attention switches to tracking the rocket on
1820 the way back to the ground, and for dual-deploy flights,
1821 waiting for the main charge to fire.
1824 To monitor whether the apogee charge operated correctly, the
1825 current descent rate is reported along with the current
1826 height. Good descent rates vary based on the choice of recovery
1827 components, but generally range from 15-30m/s on drogue and should
1828 be below 10m/s when under the main parachute in a dual-deploy flight.
1831 With GPS-equipped flight computers, you can locate the rocket in the
1832 sky using the elevation and bearing information to figure
1833 out where to look. Elevation is in degrees above the
1834 horizon. Bearing is reported in degrees relative to true
1835 north. Range can help figure out how big the rocket will
1836 appear. Ground Distance shows how far it is to a point
1837 directly under the rocket and can help figure out where the
1838 rocket is likely to land. Note that all of these values are
1839 relative to the pad location. If the elevation is near 90°,
1840 the rocket is over the pad, not over you.
1843 Finally, the igniter voltages are reported in this tab as
1844 well, both to monitor the main charge as well as to see what
1845 the status of the apogee charge is. Note that some commercial
1846 e-matches are designed to retain continuity even after being
1847 fired, and will continue to show as green or return from red to
1852 <title>Landed</title>
1856 <imagedata fileref="landed.png" width="5.5in"/>
1861 Once the rocket is on the ground, attention switches to
1862 recovery. While the radio signal is often lost once the
1863 rocket is on the ground, the last reported GPS position is
1864 generally within a short distance of the actual landing location.
1867 The last reported GPS position is reported both by
1868 latitude and longitude as well as a bearing and distance from
1869 the launch pad. The distance should give you a good idea of
1870 whether to walk or hitch a ride. Take the reported
1871 latitude and longitude and enter them into your hand-held GPS
1872 unit and have that compute a track to the landing location.
1875 Our flight computers will continue to transmit RDF
1876 tones after landing, allowing you to locate the rocket by
1877 following the radio signal if necessary. You may need to get
1878 away from the clutter of the flight line, or even get up on
1879 a hill (or your neighbor's RV roof) to receive the RDF signal.
1882 The maximum height, speed and acceleration reported
1883 during the flight are displayed for your admiring observers.
1884 The accuracy of these immediate values depends on the quality
1885 of your radio link and how many packets were received.
1886 Recovering the on-board data after flight may yield
1887 more precise results.
1890 To get more detailed information about the flight, you can
1891 click on the 'Graph Flight' button which will bring up a
1892 graph window for the current flight.
1896 <title>Table</title>
1900 <imagedata fileref="table.png" width="5.5in"/>
1905 The table view shows all of the data available from the
1906 flight computer. Probably the most useful data on
1907 this tab is the detailed GPS information, which includes
1908 horizontal dilution of precision information, and
1909 information about the signal being received from the satellites.
1913 <title>Site Map</title>
1917 <imagedata fileref="site-map.png" width="5.5in"/>
1922 When the TeleMetrum has a GPS fix, the Site Map tab will map
1923 the rocket's position to make it easier for you to locate the
1924 rocket, both while it is in the air, and when it has landed. The
1925 rocket's state is indicated by color: white for pad, red for
1926 boost, pink for fast, yellow for coast, light blue for drogue,
1927 dark blue for main, and black for landed.
1930 The map's scale is approximately 3m (10ft) per pixel. The map
1931 can be dragged using the left mouse button. The map will attempt
1932 to keep the rocket roughly centered while data is being received.
1935 Images are fetched automatically via the Google Maps Static API,
1936 and cached on disk for reuse. If map images cannot be downloaded,
1937 the rocket's path will be traced on a dark gray background
1941 You can pre-load images for your favorite launch sites
1942 before you leave home; check out the 'Preload Maps' section below.
1947 <title>Save Flight Data</title>
1949 The altimeter records flight data to its internal flash memory.
1950 TeleMetrum data is recorded at a much higher rate than the telemetry
1951 system can handle, and is not subject to radio drop-outs. As
1952 such, it provides a more complete and precise record of the
1953 flight. The 'Save Flight Data' button allows you to read the
1954 flash memory and write it to disk.
1957 Clicking on the 'Save Flight Data' button brings up a list of
1958 connected flight computers and TeleDongle devices. If you select a
1959 flight computer, the flight data will be downloaded from that
1960 device directly. If you select a TeleDongle device, flight data
1961 will be downloaded from a flight computer over radio link via the
1962 specified TeleDongle. See the chapter on Controlling An Altimeter
1963 Over The Radio Link for more information.
1966 After the device has been selected, a dialog showing the
1967 flight data saved in the device will be shown allowing you to
1968 select which flights to download and which to delete. With
1969 version 0.9 or newer firmware, you must erase flights in order
1970 for the space they consume to be reused by another
1971 flight. This prevents accidentally losing flight data
1972 if you neglect to download data before flying again. Note that
1973 if there is no more space available in the device, then no
1974 data will be recorded during the next flight.
1977 The file name for each flight log is computed automatically
1978 from the recorded flight date, altimeter serial number and
1979 flight number information.
1983 <title>Replay Flight</title>
1985 Select this button and you are prompted to select a flight
1986 record file, either a .telem file recording telemetry data or a
1987 .eeprom file containing flight data saved from the altimeter
1991 Once a flight record is selected, the flight monitor interface
1992 is displayed and the flight is re-enacted in real time. Check
1993 the Monitor Flight chapter above to learn how this window operates.
1997 <title>Graph Data</title>
1999 Select this button and you are prompted to select a flight
2000 record file, either a .telem file recording telemetry data or a
2001 .eeprom file containing flight data saved from
2005 Note that telemetry files will generally produce poor graphs
2006 due to the lower sampling rate and missed telemetry packets.
2007 Use saved flight data in .eeprom files for graphing where possible.
2010 Once a flight record is selected, a window with multiple tabs is
2014 <title>Flight Graph</title>
2018 <imagedata fileref="graph.png" width="6in" scalefit="1"/>
2023 By default, the graph contains acceleration (blue),
2024 velocity (green) and altitude (red).
2027 The graph can be zoomed into a particular area by clicking and
2028 dragging down and to the right. Once zoomed, the graph can be
2029 reset by clicking and dragging up and to the left. Holding down
2030 control and clicking and dragging allows the graph to be panned.
2031 The right mouse button causes a pop-up menu to be displayed, giving
2032 you the option save or print the plot.
2036 <title>Configure Graph</title>
2040 <imagedata fileref="graph-configure.png" width="6in" scalefit="1"/>
2045 This selects which graph elements to show, and, at the
2046 very bottom, lets you switch between metric and
2051 <title>Flight Statistics</title>
2055 <imagedata fileref="graph-stats.png" width="6in" scalefit="1"/>
2060 Shows overall data computed from the flight.
2068 <imagedata fileref="graph-map.png" width="6in" scalefit="1"/>
2073 Shows a satellite image of the flight area overlaid
2074 with the path of the flight. The red concentric
2075 circles mark the launch pad, the black concentric
2076 circles mark the landing location.
2081 <title>Export Data</title>
2083 This tool takes the raw data files and makes them available for
2084 external analysis. When you select this button, you are prompted to
2085 select a flight data file, which can be either a .eeprom or .telem.
2086 The .eeprom files contain higher resolution and more continuous data,
2087 while .telem files contain receiver signal strength information.
2088 Next, a second dialog appears which is used to select
2089 where to write the resulting file. It has a selector to choose
2090 between CSV and KML file formats.
2093 <title>Comma Separated Value Format</title>
2095 This is a text file containing the data in a form suitable for
2096 import into a spreadsheet or other external data analysis
2097 tool. The first few lines of the file contain the version and
2098 configuration information from the altimeter, then
2099 there is a single header line which labels all of the
2100 fields. All of these lines start with a '#' character which
2101 many tools can be configured to skip over.
2104 The remaining lines of the file contain the data, with each
2105 field separated by a comma and at least one space. All of
2106 the sensor values are converted to standard units, with the
2107 barometric data reported in both pressure, altitude and
2108 height above pad units.
2112 <title>Keyhole Markup Language (for Google Earth)</title>
2114 This is the format used by Google Earth to provide an overlay
2115 within that application. With this, you can use Google Earth to
2116 see the whole flight path in 3D.
2121 <title>Configure Altimeter</title>
2125 <imagedata fileref="configure-altimeter.png" width="3.6in" scalefit="1"/>
2130 Select this button and then select either an altimeter or
2131 TeleDongle Device from the list provided. Selecting a TeleDongle
2132 device will use the radio link to configure a remote altimeter.
2135 The first few lines of the dialog provide information about the
2136 connected device, including the product name,
2137 software version and hardware serial number. Below that are the
2138 individual configuration entries.
2141 At the bottom of the dialog, there are four buttons:
2148 This writes any changes to the
2149 configuration parameter block in flash memory. If you don't
2150 press this button, any changes you make will be lost.
2158 This resets the dialog to the most recently saved values,
2159 erasing any changes you have made.
2167 This reboots the device. Use this to
2168 switch from idle to pad mode by rebooting once the rocket is
2169 oriented for flight, or to confirm changes you think you saved
2178 This closes the dialog. Any unsaved changes will be
2185 The rest of the dialog contains the parameters to be configured.
2188 <title>Main Deploy Altitude</title>
2190 This sets the altitude (above the recorded pad altitude) at
2191 which the 'main' igniter will fire. The drop-down menu shows
2192 some common values, but you can edit the text directly and
2193 choose whatever you like. If the apogee charge fires below
2194 this altitude, then the main charge will fire two seconds
2195 after the apogee charge fires.
2199 <title>Apogee Delay</title>
2201 When flying redundant electronics, it's often important to
2202 ensure that multiple apogee charges don't fire at precisely
2203 the same time, as that can over pressurize the apogee deployment
2204 bay and cause a structural failure of the air-frame. The Apogee
2205 Delay parameter tells the flight computer to fire the apogee
2206 charge a certain number of seconds after apogee has been
2211 <title>Radio Frequency</title>
2213 This configures which of the frequencies to use for both
2214 telemetry and packet command mode. Note that if you set this
2215 value via packet command mode, the TeleDongle frequency will
2216 also be automatically reconfigured to match so that
2217 communication will continue afterwards.
2221 <title>RF Calibration</title>
2223 The radios in every Altus Metrum device are calibrated at the
2224 factory to ensure that they transmit and receive on the
2225 specified frequency. If you need to you can adjust the calibration
2226 by changing this value. Do not do this without understanding what
2227 the value means, read the appendix on calibration and/or the source
2228 code for more information. To change a TeleDongle's calibration,
2229 you must reprogram the unit completely.
2233 <title>Telemetry/RDF/APRS Enable</title>
2235 Enables the radio for transmission during flight. When
2236 disabled, the radio will not transmit anything during flight
2241 <title>APRS Interval</title>
2243 How often to transmit GPS information via APRS. This option
2244 is available on TeleMetrum v2 and TeleMega
2245 boards. TeleMetrum v1 boards cannot transmit APRS
2246 packets. Note that a single APRS packet takes nearly a full
2247 second to transmit, so enabling this option will prevent
2248 sending any other telemetry during that time.
2252 <title>Callsign</title>
2254 This sets the call sign included in each telemetry packet. Set this
2255 as needed to conform to your local radio regulations.
2259 <title>Maximum Flight Log Size</title>
2261 This sets the space (in kilobytes) allocated for each flight
2262 log. The available space will be divided into chunks of this
2263 size. A smaller value will allow more flights to be stored,
2264 a larger value will record data from longer flights.
2268 <title>Ignite Mode</title>
2270 TeleMetrum and TeleMini provide two igniter channels as they
2271 were originally designed as dual-deploy flight
2272 computers. This configuration parameter allows the two
2273 channels to be used in different configurations.
2277 <term>Dual Deploy</term>
2280 This is the usual mode of operation; the
2281 'apogee' channel is fired at apogee and the 'main'
2282 channel at the height above ground specified by the
2283 'Main Deploy Altitude' during descent.
2288 <term>Redundant Apogee</term>
2291 This fires both channels at
2292 apogee, the 'apogee' channel first followed after a two second
2293 delay by the 'main' channel.
2298 <term>Redundant Main</term>
2301 This fires both channels at the
2302 height above ground specified by the Main Deploy
2303 Altitude setting during descent. The 'apogee'
2304 channel is fired first, followed after a two second
2305 delay by the 'main' channel.
2312 <title>Pad Orientation</title>
2314 Because they include accelerometers, TeleMetrum and
2315 TeleMega are sensitive to the orientation of the board. By
2316 default, they expect the antenna end to point forward. This
2317 parameter allows that default to be changed, permitting the
2318 board to be mounted with the antenna pointing aft instead.
2322 <term>Antenna Up</term>
2325 In this mode, the antenna end of the
2326 flight computer must point forward, in line with the
2327 expected flight path.
2332 <term>Antenna Down</term>
2335 In this mode, the antenna end of the
2336 flight computer must point aft, in line with the
2337 expected flight path.
2344 <title>Configure Pyro Channels</title>
2348 <imagedata fileref="configure-pyro.png" width="6in" scalefit="1"/>
2353 This opens a separate window to configure the additional
2354 pyro channels available on TeleMega. One column is
2355 presented for each channel. Each row represents a single
2356 parameter, if enabled the parameter must meet the specified
2357 test for the pyro channel to be fired. See the Pyro Channels
2358 section in the System Operation chapter above for a
2359 description of these parameters.
2362 Select conditions and set the related value; the pyro
2363 channel will be activated when <emphasis>all</emphasis> of the
2364 conditions are met. Each pyro channel has a separate set of
2365 configuration values, so you can use different values for
2366 the same condition with different channels.
2369 Once you have selected the appropriate configuration for all
2370 of the necessary pyro channels, you can save the pyro
2371 configuration along with the rest of the flight computer
2372 configuration by pressing the 'Save' button in the main
2373 Configure Flight Computer window.
2378 <title>Configure AltosUI</title>
2382 <imagedata fileref="configure-altosui.png" width="2.4in" scalefit="1"/>
2387 This button presents a dialog so that you can configure the AltosUI global settings.
2390 <title>Voice Settings</title>
2392 AltosUI provides voice announcements during flight so that you
2393 can keep your eyes on the sky and still get information about
2394 the current flight status. However, sometimes you don't want
2401 <para>Turns all voice announcements on and off</para>
2405 <term>Test Voice</term>
2408 Plays a short message allowing you to verify
2409 that the audio system is working and the volume settings
2417 <title>Log Directory</title>
2419 AltosUI logs all telemetry data and saves all TeleMetrum flash
2420 data to this directory. This directory is also used as the
2421 staring point when selecting data files for display or export.
2424 Click on the directory name to bring up a directory choosing
2425 dialog, select a new directory and click 'Select Directory' to
2426 change where AltosUI reads and writes data files.
2430 <title>Callsign</title>
2432 This value is transmitted in each command packet sent from
2433 TeleDongle and received from an altimeter. It is not used in
2434 telemetry mode, as the callsign configured in the altimeter board
2435 is included in all telemetry packets. Configure this
2436 with the AltosUI operators call sign as needed to comply with
2437 your local radio regulations.
2440 Note that to successfully command a flight computer over the radio
2441 (to configure the altimeter, monitor idle, or fire pyro charges),
2442 the callsign configured here must exactly match the callsign
2443 configured in the flight computer. This matching is case
2448 <title>Imperial Units</title>
2450 This switches between metric units (meters) and imperial
2451 units (feet and miles). This affects the display of values
2452 use during flight monitoring, configuration, data graphing
2453 and all of the voice announcements. It does not change the
2454 units used when exporting to CSV files, those are always
2455 produced in metric units.
2459 <title>Font Size</title>
2461 Selects the set of fonts used in the flight monitor
2462 window. Choose between the small, medium and large sets.
2466 <title>Serial Debug</title>
2468 This causes all communication with a connected device to be
2469 dumped to the console from which AltosUI was started. If
2470 you've started it from an icon or menu entry, the output
2471 will simply be discarded. This mode can be useful to debug
2472 various serial communication issues.
2476 <title>Manage Frequencies</title>
2478 This brings up a dialog where you can configure the set of
2479 frequencies shown in the various frequency menus. You can
2480 add as many as you like, or even reconfigure the default
2481 set. Changing this list does not affect the frequency
2482 settings of any devices, it only changes the set of
2483 frequencies shown in the menus.
2488 <title>Configure Groundstation</title>
2492 <imagedata fileref="configure-groundstation.png" width="3.1in" scalefit="1"/>
2497 Select this button and then select a TeleDongle Device from the list provided.
2500 The first few lines of the dialog provide information about the
2501 connected device, including the product name,
2502 software version and hardware serial number. Below that are the
2503 individual configuration entries.
2506 Note that the TeleDongle itself doesn't save any configuration
2507 data, the settings here are recorded on the local machine in
2508 the Java preferences database. Moving the TeleDongle to
2509 another machine, or using a different user account on the same
2510 machine will cause settings made here to have no effect.
2513 At the bottom of the dialog, there are three buttons:
2520 This writes any changes to the
2521 local Java preferences file. If you don't
2522 press this button, any changes you make will be lost.
2530 This resets the dialog to the most recently saved values,
2531 erasing any changes you have made.
2539 This closes the dialog. Any unsaved changes will be
2546 The rest of the dialog contains the parameters to be configured.
2549 <title>Frequency</title>
2551 This configures the frequency to use for both telemetry and
2552 packet command mode. Set this before starting any operation
2553 involving packet command mode so that it will use the right
2554 frequency. Telemetry monitoring mode also provides a menu to
2555 change the frequency, and that menu also sets the same Java
2556 preference value used here.
2560 <title>Radio Calibration</title>
2562 The radios in every Altus Metrum device are calibrated at the
2563 factory to ensure that they transmit and receive on the
2564 specified frequency. To change a TeleDongle's calibration,
2565 you must reprogram the unit completely, so this entry simply
2566 shows the current value and doesn't allow any changes.
2571 <title>Flash Image</title>
2573 This reprograms Altus Metrum devices with new
2574 firmware. TeleMetrum v1.x, TeleDongle, TeleMini and TeleBT are
2575 all reprogrammed by using another similar unit as a
2576 programming dongle (pair programming). TeleMega, TeleMetrum v2
2577 and EasyMini are all programmed directly over their USB ports
2578 (self programming). Please read the directions for flashing
2579 devices in the Updating Device Firmware chapter below.
2583 <title>Fire Igniter</title>
2587 <imagedata fileref="fire-igniter.png" width="1.2in" scalefit="1"/>
2592 This activates the igniter circuits in the flight computer to help
2593 test recovery systems deployment. Because this command can operate
2594 over the Packet Command Link, you can prepare the rocket as
2595 for flight and then test the recovery system without needing
2596 to snake wires inside the air-frame.
2599 Selecting the 'Fire Igniter' button brings up the usual device
2600 selection dialog. Pick the desired device. This brings up another
2601 window which shows the current continuity test status for both
2602 apogee and main charges.
2605 Next, select the desired igniter to fire. This will enable the
2609 Select the 'Arm' button. This enables the 'Fire' button. The
2610 word 'Arm' is replaced by a countdown timer indicating that
2611 you have 10 seconds to press the 'Fire' button or the system
2612 will deactivate, at which point you start over again at
2613 selecting the desired igniter.
2617 <title>Scan Channels</title>
2621 <imagedata fileref="scan-channels.png" width="3.2in" scalefit="1"/>
2626 This listens for telemetry packets on all of the configured
2627 frequencies, displaying information about each device it
2628 receives a packet from. You can select which of the three
2629 telemetry formats should be tried; by default, it only listens
2630 for the standard telemetry packets used in v1.0 and later
2635 <title>Load Maps</title>
2639 <imagedata fileref="load-maps.png" width="5.2in" scalefit="1"/>
2644 Before heading out to a new launch site, you can use this to
2645 load satellite images in case you don't have internet
2646 connectivity at the site. This loads a fairly large area
2647 around the launch site, which should cover any flight you're likely to make.
2650 There's a drop-down menu of launch sites we know about; if
2651 your favorites aren't there, please let us know the lat/lon
2652 and name of the site. The contents of this list are actually
2653 downloaded from our server at run-time, so as new sites are sent
2654 in, they'll get automatically added to this list.
2657 If the launch site isn't in the list, you can manually enter the lat/lon values
2660 Clicking the 'Load Map' button will fetch images from Google
2661 Maps; note that Google limits how many images you can fetch at
2662 once, so if you load more than one launch site, you may get
2663 some gray areas in the map which indicate that Google is tired
2664 of sending data to you. Try again later.
2668 <title>Monitor Idle</title>
2670 This brings up a dialog similar to the Monitor Flight UI,
2671 except it works with the altimeter in “idle” mode by sending
2672 query commands to discover the current state rather than
2673 listening for telemetry packets. Because this uses command
2674 mode, it needs to have the TeleDongle and flight computer
2675 callsigns match exactly. If you can receive telemetry, but
2676 cannot manage to run Monitor Idle, then it's very likely that
2677 your callsigns are different in some way.
2682 <title>AltosDroid</title>
2684 AltosDroid provides the same flight monitoring capabilities as
2685 AltosUI, but runs on Android devices and is designed to connect
2686 to a TeleBT receiver over Bluetooth™. AltosDroid monitors
2687 telemetry data, logging it to internal storage in the Android
2688 device, and presents that data in a UI the same way the 'Monitor
2689 Flight' window does in AltosUI.
2692 This manual will explain how to configure AltosDroid, connect
2693 to TeleBT, operate the flight monitoring interface and describe
2694 what the displayed data means.
2697 <title>Installing AltosDroid</title>
2699 AltosDroid is available from the Google Play store. To install
2700 it on your Android device, open the Google Play Store
2701 application and search for “altosdroid”. Make sure you don't
2702 have a space between “altos” and “droid” or you probably won't
2703 find what you want. That should bring you to the right page
2704 from which you can download and install the application.
2708 <title>Connecting to TeleBT</title>
2710 Press the Android 'Menu' button or soft-key to see the
2711 configuration options available. Select the 'Connect a device'
2712 option and then the 'Scan for devices' entry at the bottom to
2713 look for your TeleBT device. Select your device, and when it
2714 asks for the code, enter '1234'.
2717 Subsequent connections will not require you to enter that
2718 code, and your 'paired' device will appear in the list without
2723 <title>Configuring AltosDroid</title>
2725 The only configuration option available for AltosDroid is
2726 which frequency to listen on. Press the Android 'Menu' button
2727 or soft-key and pick the 'Select radio frequency' entry. That
2728 brings up a menu of pre-set radio frequencies; pick the one
2729 which matches your altimeter.
2733 <title>AltosDroid Flight Monitoring</title>
2735 AltosDroid is designed to mimic the AltosUI flight monitoring
2736 display, providing separate tabs for each stage of your rocket
2737 flight along with a tab containing a map of the local area
2738 with icons marking the current location of the altimeter and
2744 The 'Launch Pad' tab shows information used to decide when the
2745 rocket is ready for flight. The first elements include red/green
2746 indicators, if any of these is red, you'll want to evaluate
2747 whether the rocket is ready to launch:
2750 <term>Battery Voltage</term>
2753 This indicates whether the Li-Po battery
2754 powering the TeleMetrum has sufficient charge to last for
2755 the duration of the flight. A value of more than
2756 3.8V is required for a 'GO' status.
2761 <term>Apogee Igniter Voltage</term>
2764 This indicates whether the apogee
2765 igniter has continuity. If the igniter has a low
2766 resistance, then the voltage measured here will be close
2767 to the Li-Po battery voltage. A value greater than 3.2V is
2768 required for a 'GO' status.
2773 <term>Main Igniter Voltage</term>
2776 This indicates whether the main
2777 igniter has continuity. If the igniter has a low
2778 resistance, then the voltage measured here will be close
2779 to the Li-Po battery voltage. A value greater than 3.2V is
2780 required for a 'GO' status.
2785 <term>On-board Data Logging</term>
2788 This indicates whether there is
2789 space remaining on-board to store flight data for the
2790 upcoming flight. If you've downloaded data, but failed
2791 to erase flights, there may not be any space
2792 left. TeleMetrum can store multiple flights, depending
2793 on the configured maximum flight log size. TeleMini
2794 stores only a single flight, so it will need to be
2795 downloaded and erased after each flight to capture
2796 data. This only affects on-board flight logging; the
2797 altimeter will still transmit telemetry and fire
2798 ejection charges at the proper times.
2803 <term>GPS Locked</term>
2806 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
2807 currently able to compute position information. GPS requires
2808 at least 4 satellites to compute an accurate position.
2813 <term>GPS Ready</term>
2816 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
2817 10 consecutive positions without losing lock. This ensures
2818 that the GPS receiver has reliable reception from the
2826 The Launchpad tab also shows the computed launch pad position
2827 and altitude, averaging many reported positions to improve the
2828 accuracy of the fix.
2833 <title>Downloading Flight Logs</title>
2835 AltosDroid always saves every bit of telemetry data it
2836 receives. To download that to a computer for use with AltosUI,
2837 simply remove the SD card from your Android device, or connect
2838 your device to your computer's USB port and browse the files
2839 on that device. You will find '.telem' files in the TeleMetrum
2840 directory that will work with AltosUI directly.
2845 <title>Using Altus Metrum Products</title>
2847 <title>Being Legal</title>
2849 First off, in the US, you need an <ulink url="http://www.altusmetrum.org/Radio/">amateur radio license</ulink> or
2850 other authorization to legally operate the radio transmitters that are part
2855 <title>In the Rocket</title>
2857 In the rocket itself, you just need a flight computer and
2858 a single-cell, 3.7 volt nominal Li-Po rechargeable battery. An
2859 850mAh battery weighs less than a 9V alkaline battery, and will
2860 run a TeleMetrum or TeleMega for hours.
2861 A 110mAh battery weighs less than a triple A battery and is a good
2862 choice for use with TeleMini.
2865 By default, we ship flight computers with a simple wire antenna.
2866 If your electronics bay or the air-frame it resides within is made
2867 of carbon fiber, which is opaque to RF signals, you may prefer to
2868 install an SMA connector so that you can run a coaxial cable to an
2869 antenna mounted elsewhere in the rocket. However, note that the
2870 GPS antenna is fixed on all current products, so you really want
2871 to install the flight computer in a bay made of RF-transparent
2872 materials if at all possible.
2876 <title>On the Ground</title>
2878 To receive the data stream from the rocket, you need an antenna and short
2879 feed-line connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. If possible, use an SMA to BNC
2880 adapter instead of feedline between the antenna feedpoint and
2881 TeleDongle, as this will give you the best performance. The
2882 TeleDongle in turn plugs directly into the USB port on a notebook
2883 computer. Because TeleDongle looks like a simple serial port, your computer
2884 does not require special device drivers... just plug it in.
2887 The GUI tool, AltosUI, is written in Java and runs across
2888 Linux, Mac OS and Windows. There's also a suite of C tools
2889 for Linux which can perform most of the same tasks.
2892 Alternatively, a TeleBT attached with an SMA to BNC adapter at the
2893 feed point of a hand-held yagi used in conjunction with an Android
2894 device running AltosDroid makes an outstanding ground station.
2897 After the flight, you can use the radio link to extract the more detailed data
2898 logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
2899 TeleMetrum board directly. Pulling out the data without having to open up
2900 the rocket is pretty cool! A USB cable is also how you charge the Li-Po
2901 battery, so you'll want one of those anyway... the same cable used by lots
2902 of digital cameras and other modern electronic stuff will work fine.
2905 If your rocket lands out of sight, you may enjoy having a hand-held
2906 GPS receiver, so that you can put in a way-point for the last
2907 reported rocket position before touch-down. This makes looking for
2908 your rocket a lot like Geo-Caching... just go to the way-point and
2909 look around starting from there. AltosDroid on an Android device
2910 with GPS receiver works great for this, too!
2913 You may also enjoy having a ham radio “HT” that covers the 70cm band... you
2914 can use that with your antenna to direction-find the rocket on the ground
2915 the same way you can use a Walston or Beeline tracker. This can be handy
2916 if the rocket is hiding in sage brush or a tree, or if the last GPS position
2917 doesn't get you close enough because the rocket dropped into a canyon, or
2918 the wind is blowing it across a dry lake bed, or something like that... Keith
2919 currently uses a Yaesu VX-7R, Bdale has a Baofung UV-5R
2920 which isn't as nice, but was a whole lot cheaper.
2923 So, to recap, on the ground the hardware you'll need includes:
2924 <orderedlist inheritnum='inherit' numeration='arabic'>
2927 an antenna and feed-line or adapter
2942 optionally, a hand-held GPS receiver
2947 optionally, an HT or receiver covering 435 MHz
2953 The best hand-held commercial directional antennas we've found for radio
2954 direction finding rockets are from
2955 <ulink url="http://www.arrowantennas.com/" >
2958 The 440-3 and 440-5 are both good choices for finding a
2959 TeleMetrum- or TeleMini- equipped rocket when used with a suitable
2960 70cm HT. TeleDongle and an SMA to BNC adapter fit perfectly
2961 between the driven element and reflector of Arrow antennas.
2965 <title>Data Analysis</title>
2967 Our software makes it easy to log the data from each flight, both the
2968 telemetry received during the flight itself, and the more
2969 complete data log recorded in the flash memory on the altimeter
2970 board. Once this data is on your computer, our post-flight tools make it
2971 easy to quickly get to the numbers everyone wants, like apogee altitude,
2972 max acceleration, and max velocity. You can also generate and view a
2973 standard set of plots showing the altitude, acceleration, and
2974 velocity of the rocket during flight. And you can even export a TeleMetrum data file
2975 usable with Google Maps and Google Earth for visualizing the flight path
2976 in two or three dimensions!
2979 Our ultimate goal is to emit a set of files for each flight that can be
2980 published as a web page per flight, or just viewed on your local disk with
2985 <title>Future Plans</title>
2987 We've designed a simple GPS based radio tracker called TeleGPS.
2988 If all goes well, we hope to introduce this in the first
2992 We have designed and prototyped several “companion boards” that
2993 can attach to the companion connector on TeleMetrum and TeleMega
2994 flight computers to collect more data, provide more pyro channels,
2995 and so forth. We do not yet know if or when any of these boards
2996 will be produced in enough quantity to sell. If you have specific
2997 interests for data collection or control of events in your rockets
2998 beyond the capabilities of our existing productions, please let
3002 Because all of our work is open, both the hardware designs and the
3003 software, if you have some great idea for an addition to the current
3004 Altus Metrum family, feel free to dive in and help! Or let us know
3005 what you'd like to see that we aren't already working on, and maybe
3006 we'll get excited about it too...
3010 <ulink url="http://altusmetrum.org/">web site</ulink> for more news
3011 and information as our family of products evolves!
3016 <title>Altimeter Installation Recommendations</title>
3018 Building high-power rockets that fly safely is hard enough. Mix
3019 in some sophisticated electronics and a bunch of radio energy
3020 and some creativity and/or compromise may be required. This chapter
3021 contains some suggestions about how to install Altus Metrum
3022 products into a rocket air-frame, including how to safely and
3023 reliably mix a variety of electronics into the same air-frame.
3026 <title>Mounting the Altimeter</title>
3028 The first consideration is to ensure that the altimeter is
3029 securely fastened to the air-frame. For most of our products, we
3030 prefer nylon standoffs and nylon screws; they're good to at least 50G
3031 and cannot cause any electrical issues on the board. Metal screws
3032 and standoffs are fine, too, just be careful to avoid electrical
3033 shorts! For TeleMini v1.0, we usually cut small pieces of 1/16 inch
3035 under the screw holes, and then take 2x56 nylon screws and
3036 screw them through the TeleMini mounting holes, through the
3037 balsa and into the underlying material.
3039 <orderedlist inheritnum='inherit' numeration='arabic'>
3042 Make sure accelerometer-equipped products like TeleMetrum and
3043 TeleMega are aligned precisely along the axis of
3044 acceleration so that the accelerometer can accurately
3045 capture data during the flight.
3050 Watch for any metal touching components on the
3051 board. Shorting out connections on the bottom of the board
3052 can cause the altimeter to fail during flight.
3058 <title>Dealing with the Antenna</title>
3060 The antenna supplied is just a piece of solid, insulated,
3061 wire. If it gets damaged or broken, it can be easily
3062 replaced. It should be kept straight and not cut; bending or
3063 cutting it will change the resonant frequency and/or
3064 impedance, making it a less efficient radiator and thus
3065 reducing the range of the telemetry signal.
3068 Keeping metal away from the antenna will provide better range
3069 and a more even radiation pattern. In most rockets, it's not
3070 entirely possible to isolate the antenna from metal
3071 components; there are often bolts, all-thread and wires from other
3072 electronics to contend with. Just be aware that the more stuff
3073 like this around the antenna, the lower the range.
3076 Make sure the antenna is not inside a tube made or covered
3077 with conducting material. Carbon fiber is the most common
3078 culprit here -- CF is a good conductor and will effectively
3079 shield the antenna, dramatically reducing signal strength and
3080 range. Metallic flake paint is another effective shielding
3081 material which should be avoided around any antennas.
3084 If the ebay is large enough, it can be convenient to simply
3085 mount the altimeter at one end and stretch the antenna out
3086 inside. Taping the antenna to the sled can keep it straight
3087 under acceleration. If there are metal rods, keep the
3088 antenna as far away as possible.
3091 For a shorter ebay, it's quite practical to have the antenna
3092 run through a bulkhead and into an adjacent bay. Drill a small
3093 hole in the bulkhead, pass the antenna wire through it and
3094 then seal it up with glue or clay. We've also used acrylic
3095 tubing to create a cavity for the antenna wire. This works a
3096 bit better in that the antenna is known to stay straight and
3097 not get folded by recovery components in the bay. Angle the
3098 tubing towards the side wall of the rocket and it ends up
3099 consuming very little space.
3102 If you need to place the UHF antenna at a distance from the
3103 altimeter, you can replace the antenna with an edge-mounted
3104 SMA connector, and then run 50Ω coax from the board to the
3105 antenna. Building a remote antenna is beyond the scope of this
3110 <title>Preserving GPS Reception</title>
3112 The GPS antenna and receiver used in TeleMetrum and TeleMega is
3113 highly sensitive and normally have no trouble tracking enough
3114 satellites to provide accurate position information for
3115 recovering the rocket. However, there are many ways the GPS signal
3116 can end up attenuated, negatively affecting GPS performance.
3117 <orderedlist inheritnum='inherit' numeration='arabic'>
3120 Conductive tubing or coatings. Carbon fiber and metal
3121 tubing, or metallic paint will all dramatically attenuate the
3122 GPS signal. We've never heard of anyone successfully
3123 receiving GPS from inside these materials.
3128 Metal components near the GPS patch antenna. These will
3129 de-tune the patch antenna, changing the resonant frequency
3130 away from the L1 carrier and reduce the effectiveness of the
3131 antenna. You can place as much stuff as you like beneath the
3132 antenna as that's covered with a ground plane. But, keep
3133 wires and metal out from above the patch antenna.
3140 <title>Radio Frequency Interference</title>
3142 Any altimeter will generate RFI; the digital circuits use
3143 high-frequency clocks that spray radio interference across a
3144 wide band. Altus Metrum altimeters generate intentional radio
3145 signals as well, increasing the amount of RF energy around the board.
3148 Rocketry altimeters also use precise sensors measuring air
3149 pressure and acceleration. Tiny changes in voltage can cause
3150 these sensor readings to vary by a huge amount. When the
3151 sensors start mis-reporting data, the altimeter can either
3152 fire the igniters at the wrong time, or not fire them at all.
3155 Voltages are induced when radio frequency energy is
3156 transmitted from one circuit to another. Here are things that
3157 influence the induced voltage and current:
3162 Keep wires from different circuits apart. Moving circuits
3163 further apart will reduce RFI.
3168 Avoid parallel wires from different circuits. The longer two
3169 wires run parallel to one another, the larger the amount of
3170 transferred energy. Cross wires at right angles to reduce
3176 Twist wires from the same circuits. Two wires the same
3177 distance from the transmitter will get the same amount of
3178 induced energy which will then cancel out. Any time you have
3179 a wire pair running together, twist the pair together to
3180 even out distances and reduce RFI. For altimeters, this
3181 includes battery leads, switch hookups and igniter
3187 Avoid resonant lengths. Know what frequencies are present
3188 in the environment and avoid having wire lengths near a
3189 natural resonant length. Altus Metrum products transmit on the
3190 70cm amateur band, so you should avoid lengths that are a
3191 simple ratio of that length; essentially any multiple of ¼
3192 of the wavelength (17.5cm).
3198 <title>The Barometric Sensor</title>
3200 Altusmetrum altimeters measure altitude with a barometric
3201 sensor, essentially measuring the amount of air above the
3202 rocket to figure out how high it is. A large number of
3203 measurements are taken as the altimeter initializes itself to
3204 figure out the pad altitude. Subsequent measurements are then
3205 used to compute the height above the pad.
3208 To accurately measure atmospheric pressure, the ebay
3209 containing the altimeter must be vented outside the
3210 air-frame. The vent must be placed in a region of linear
3211 airflow, have smooth edges, and away from areas of increasing or
3212 decreasing pressure.
3215 All barometric sensors are quite sensitive to chemical damage from
3216 the products of APCP or BP combustion, so make sure the ebay is
3217 carefully sealed from any compartment which contains ejection
3222 <title>Ground Testing</title>
3224 The most important aspect of any installation is careful
3225 ground testing. Bringing an air-frame up to the LCO table which
3226 hasn't been ground tested can lead to delays or ejection
3227 charges firing on the pad, or, even worse, a recovery system
3231 Do a 'full systems' test that includes wiring up all igniters
3232 without any BP and turning on all of the electronics in flight
3233 mode. This will catch any mistakes in wiring and any residual
3234 RFI issues that might accidentally fire igniters at the wrong
3235 time. Let the air-frame sit for several minutes, checking for
3236 adequate telemetry signal strength and GPS lock. If any igniters
3237 fire unexpectedly, find and resolve the issue before loading any
3241 Ground test the ejection charges. Prepare the rocket for
3242 flight, loading ejection charges and igniters. Completely
3243 assemble the air-frame and then use the 'Fire Igniters'
3244 interface through a TeleDongle to command each charge to
3245 fire. Make sure the charge is sufficient to robustly separate
3246 the air-frame and deploy the recovery system.
3251 <title>Updating Device Firmware</title>
3253 TeleMega, TeleMetrum v2 and EasyMini are all programmed directly
3254 over their USB connectors (self programming). TeleMetrum v1, TeleMini and
3255 TeleDongle are all programmed by using another device as a
3256 programmer (pair programming). It's important to recognize which
3257 kind of devices you have before trying to reprogram them.
3260 You may wish to begin by ensuring you have current firmware images.
3261 These are distributed as part of the AltOS software bundle that
3262 also includes the AltosUI ground station program. Newer ground
3263 station versions typically work fine with older firmware versions,
3264 so you don't need to update your devices just to try out new
3265 software features. You can always download the most recent
3266 version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
3269 If you need to update the firmware on a TeleDongle, we recommend
3270 updating the altimeter first, before updating TeleDongle. However,
3271 note that TeleDongle rarely need to be updated. Any firmware version
3272 1.0.1 or later will work, version 1.2.1 may have improved receiver
3273 performance slightly.
3276 Self-programmable devices (TeleMega, TeleMetrum v2 and EasyMini)
3277 are reprogrammed by connecting them to your computer over USB
3281 Updating TeleMega, TeleMetrum v2 or EasyMini Firmware
3283 <orderedlist inheritnum='inherit' numeration='arabic'>
3286 Attach a battery and power switch to the target
3287 device. Power up the device.
3292 Using a Micro USB cable, connect the target device to your
3293 computer's USB socket.
3298 Run AltosUI, and select 'Flash Image' from the File menu.
3303 Select the target device in the Device Selection dialog.
3308 Select the image you want to flash to the device, which
3309 should have a name in the form
3310 <product>-v<product-version>-<software-version>.ihx, such
3311 as TeleMega-v1.0-1.3.0.ihx.
3316 Make sure the configuration parameters are reasonable
3317 looking. If the serial number and/or RF configuration
3318 values aren't right, you'll need to change them.
3323 Hit the 'OK' button and the software should proceed to flash
3324 the device with new firmware, showing a progress bar.
3329 Verify that the device is working by using the 'Configure
3330 Altimeter' item to check over the configuration.
3335 <title>Recovering From Self-Flashing Failure</title>
3337 If the firmware loading fails, it can leave the device
3338 unable to boot. Not to worry, you can force the device to
3339 start the boot loader instead, which will let you try to
3340 flash the device again.
3343 On each device, connecting two pins from one of the exposed
3344 connectors will force the boot loader to start, even if the
3345 regular operating system has been corrupted in some way.
3349 <term>TeleMega</term>
3352 Connect pin 6 and pin 1 of the companion connector. Pin 1
3353 can be identified by the square pad around it, and then
3354 the pins could sequentially across the board. Be very
3355 careful to <emphasis>not</emphasis> short pin 8 to
3356 anything as that is connected directly to the battery. Pin
3357 7 carries 3.3V and the board will crash if that is
3358 connected to pin 1, but shouldn't damage the board.
3363 <term>TeleMetrum v2</term>
3366 Connect pin 6 and pin 1 of the companion connector. Pin 1
3367 can be identified by the square pad around it, and then
3368 the pins could sequentially across the board. Be very
3369 careful to <emphasis>not</emphasis> short pin 8 to
3370 anything as that is connected directly to the battery. Pin
3371 7 carries 3.3V and the board will crash if that is
3372 connected to pin 1, but shouldn't damage the board.
3377 <term>EasyMini</term>
3380 Connect pin 6 and pin 1 of the debug connector, which is
3381 the six holes next to the beeper. Pin 1 can be identified
3382 by the square pad around it, and then the pins could
3383 sequentially across the board, making Pin 6 the one on the
3384 other end of the row.
3392 <title>Pair Programming</title>
3394 The big concept to understand is that you have to use a
3395 TeleMega, TeleMetrum or TeleDongle as a programmer to update a
3396 pair programmed device. Due to limited memory resources in the
3397 cc1111, we don't support programming directly over USB for these
3402 <title>Updating TeleMetrum v1.x Firmware</title>
3403 <orderedlist inheritnum='inherit' numeration='arabic'>
3406 Find the 'programming cable' that you got as part of the starter
3407 kit, that has a red 8-pin MicroMaTch connector on one end and a
3408 red 4-pin MicroMaTch connector on the other end.
3413 Take the 2 screws out of the TeleDongle case to get access
3414 to the circuit board.
3419 Plug the 8-pin end of the programming cable to the
3420 matching connector on the TeleDongle, and the 4-pin end to the
3421 matching connector on the TeleMetrum.
3422 Note that each MicroMaTch connector has an alignment pin that
3423 goes through a hole in the PC board when you have the cable
3429 Attach a battery to the TeleMetrum board.
3434 Plug the TeleDongle into your computer's USB port, and power
3440 Run AltosUI, and select 'Flash Image' from the File menu.
3445 Pick the TeleDongle device from the list, identifying it as the
3451 Select the image you want put on the TeleMetrum, which should have a
3452 name in the form telemetrum-v1.2-1.0.0.ihx. It should be visible
3453 in the default directory, if not you may have to poke around
3454 your system to find it.
3459 Make sure the configuration parameters are reasonable
3460 looking. If the serial number and/or RF configuration
3461 values aren't right, you'll need to change them.
3466 Hit the 'OK' button and the software should proceed to flash
3467 the TeleMetrum with new firmware, showing a progress bar.
3472 Confirm that the TeleMetrum board seems to have updated OK, which you
3473 can do by plugging in to it over USB and using a terminal program
3474 to connect to the board and issue the 'v' command to check
3480 If something goes wrong, give it another try.
3486 <title>Updating TeleMini Firmware</title>
3487 <orderedlist inheritnum='inherit' numeration='arabic'>
3490 You'll need a special 'programming cable' to reprogram the
3491 TeleMini. You can make your own using an 8-pin MicroMaTch
3492 connector on one end and a set of four pins on the other.
3497 Take the 2 screws out of the TeleDongle case to get access
3498 to the circuit board.
3503 Plug the 8-pin end of the programming cable to the matching
3504 connector on the TeleDongle, and the 4-pins into the holes
3505 in the TeleMini circuit board. Note that the MicroMaTch
3506 connector has an alignment pin that goes through a hole in
3507 the PC board when you have the cable oriented correctly, and
3508 that pin 1 on the TeleMini board is marked with a square pad
3509 while the other pins have round pads.
3514 Attach a battery to the TeleMini board.
3519 Plug the TeleDongle into your computer's USB port, and power
3525 Run AltosUI, and select 'Flash Image' from the File menu.
3530 Pick the TeleDongle device from the list, identifying it as the
3536 Select the image you want put on the TeleMini, which should have a
3537 name in the form telemini-v1.0-1.0.0.ihx. It should be visible
3538 in the default directory, if not you may have to poke around
3539 your system to find it.
3544 Make sure the configuration parameters are reasonable
3545 looking. If the serial number and/or RF configuration
3546 values aren't right, you'll need to change them.
3551 Hit the 'OK' button and the software should proceed to flash
3552 the TeleMini with new firmware, showing a progress bar.
3557 Confirm that the TeleMini board seems to have updated OK, which you
3558 can do by configuring it over the radio link through the TeleDongle, or
3559 letting it come up in “flight” mode and listening for telemetry.
3564 If something goes wrong, give it another try.
3570 <title>Updating TeleDongle Firmware</title>
3572 Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
3573 firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
3575 <orderedlist inheritnum='inherit' numeration='arabic'>
3578 Find the 'programming cable' that you got as part of the starter
3579 kit, that has a red 8-pin MicroMaTch connector on one end and a
3580 red 4-pin MicroMaTch connector on the other end.
3585 Find the USB cable that you got as part of the starter kit, and
3586 plug the “mini” end in to the mating connector on TeleMetrum or TeleDongle.
3591 Take the 2 screws out of the TeleDongle case to get access
3592 to the circuit board.
3597 Plug the 8-pin end of the programming cable to the
3598 matching connector on the programmer, and the 4-pin end to the
3599 matching connector on the TeleDongle.
3600 Note that each MicroMaTch connector has an alignment pin that
3601 goes through a hole in the PC board when you have the cable
3607 Attach a battery to the TeleMetrum board if you're using one.
3612 Plug both the programmer and the TeleDongle into your computer's USB
3613 ports, and power up the programmer.
3618 Run AltosUI, and select 'Flash Image' from the File menu.
3623 Pick the programmer device from the list, identifying it as the
3629 Select the image you want put on the TeleDongle, which should have a
3630 name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
3631 in the default directory, if not you may have to poke around
3632 your system to find it.
3637 Make sure the configuration parameters are reasonable
3638 looking. If the serial number and/or RF configuration
3639 values aren't right, you'll need to change them. The TeleDongle
3640 serial number is on the “bottom” of the circuit board, and can
3641 usually be read through the translucent blue plastic case without
3642 needing to remove the board from the case.
3647 Hit the 'OK' button and the software should proceed to flash
3648 the TeleDongle with new firmware, showing a progress bar.
3653 Confirm that the TeleDongle board seems to have updated OK, which you
3654 can do by plugging in to it over USB and using a terminal program
3655 to connect to the board and issue the 'v' command to check
3656 the version, etc. Once you're happy, remove the programming cable
3657 and put the cover back on the TeleDongle.
3662 If something goes wrong, give it another try.
3667 Be careful removing the programming cable from the locking 8-pin
3668 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
3669 screwdriver or knife blade to gently pry the locking ears out
3670 slightly to extract the connector. We used a locking connector on
3671 TeleMetrum to help ensure that the cabling to companion boards
3672 used in a rocket don't ever come loose accidentally in flight.
3677 <title>Hardware Specifications</title>
3680 TeleMega Specifications
3685 Recording altimeter for model rocketry.
3690 Supports dual deployment and four auxiliary pyro channels
3691 (a total of 6 events).
3696 70cm 40mW ham-band transceiver for telemetry down-link.
3701 Barometric pressure sensor good to 100k feet MSL.
3706 1-axis high-g accelerometer for motor characterization, capable of
3712 9-axis IMU including integrated 3-axis accelerometer,
3713 3-axis gyroscope and 3-axis magnetometer.
3718 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
3723 On-board 8 Megabyte non-volatile memory for flight data storage.
3728 USB interface for battery charging, configuration, and data recovery.
3733 Fully integrated support for Li-Po rechargeable batteries.
3738 Can use either main system Li-Po or optional separate pyro battery
3744 3.25 x 1.25 inch board designed to fit inside 38mm air-frame coupler tube.
3751 TeleMetrum v2 Specifications
3756 Recording altimeter for model rocketry.
3761 Supports dual deployment (can fire 2 ejection charges).
3766 70cm, 40mW ham-band transceiver for telemetry down-link.
3771 Barometric pressure sensor good to 100k feet MSL.
3776 1-axis high-g accelerometer for motor characterization, capable of
3782 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
3787 On-board 8 Megabyte non-volatile memory for flight data storage.
3792 USB interface for battery charging, configuration, and data recovery.
3797 Fully integrated support for Li-Po rechargeable batteries.
3802 Uses Li-Po to fire e-matches, can be modified to support
3803 optional separate pyro battery if needed.
3808 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
3814 <title>TeleMetrum v1 Specifications</title>
3818 Recording altimeter for model rocketry.
3823 Supports dual deployment (can fire 2 ejection charges).
3828 70cm, 10mW ham-band transceiver for telemetry down-link.
3833 Barometric pressure sensor good to 45k feet MSL.
3838 1-axis high-g accelerometer for motor characterization, capable of
3839 +/- 50g using default part.
3844 On-board, integrated GPS receiver with 5Hz update rate capability.
3849 On-board 1 megabyte non-volatile memory for flight data storage.
3854 USB interface for battery charging, configuration, and data recovery.
3859 Fully integrated support for Li-Po rechargeable batteries.
3864 Uses Li-Po to fire e-matches, can be modified to support
3865 optional separate pyro battery if needed.
3870 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
3877 TeleMini v2.0 Specifications
3882 Recording altimeter for model rocketry.
3887 Supports dual deployment (can fire 2 ejection charges).
3892 70cm, 10mW ham-band transceiver for telemetry down-link.
3897 Barometric pressure sensor good to 100k feet MSL.
3902 On-board 1 megabyte non-volatile memory for flight data storage.
3907 USB interface for configuration, and data recovery.
3912 Support for Li-Po rechargeable batteries (using an
3913 external charger), or any 3.7-15V external battery.
3918 Uses Li-Po to fire e-matches, can be modified to support
3919 optional separate pyro battery if needed.
3924 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
3931 TeleMini v1.0 Specifications
3936 Recording altimeter for model rocketry.
3941 Supports dual deployment (can fire 2 ejection charges).
3946 70cm, 10mW ham-band transceiver for telemetry down-link.
3951 Barometric pressure sensor good to 45k feet MSL.
3956 On-board 5 kilobyte non-volatile memory for flight data storage.
3961 RF interface for configuration, and data recovery.
3966 Support for Li-Po rechargeable batteries, using an external charger.
3971 Uses Li-Po to fire e-matches, can be modified to support
3972 optional separate pyro battery if needed.
3977 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube.
3984 EasyMini Specifications
3989 Recording altimeter for model rocketry.
3994 Supports dual deployment (can fire 2 ejection charges).
3999 Barometric pressure sensor good to 100k feet MSL.
4004 On-board 1 megabyte non-volatile memory for flight data storage.
4009 USB interface for configuration, and data recovery.
4014 Support for Li-Po rechargeable batteries (using an
4015 external charger), or any 3.7-15V external battery.
4020 Uses Li-Po to fire e-matches, can be modified to support
4021 optional separate pyro battery if needed.
4026 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
4035 <emphasis>TeleMetrum seems to shut off when disconnected from the
4036 computer.</emphasis> <?linebreak?>
4037 Make sure the battery is adequately charged. Remember the
4038 unit will pull more power than the USB port can deliver before the
4039 GPS enters “locked” mode. The battery charges best when TeleMetrum
4043 <emphasis>It's impossible to stop the TeleDongle when it's in “p” mode, I have
4044 to unplug the USB cable? </emphasis><?linebreak?>
4045 Make sure you have tried to “escape out” of
4046 this mode. If this doesn't work the reboot procedure for the
4047 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
4048 outgoing buffer IF your “escape out” ('~~') does not work.
4049 At this point using either 'ao-view' (or possibly
4050 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
4054 <emphasis>The amber LED (on the TeleMetrum) lights up when both
4055 battery and USB are connected. Does this mean it's charging?
4056 </emphasis><?linebreak?>
4057 Yes, the yellow LED indicates the charging at the 'regular' rate.
4058 If the led is out but the unit is still plugged into a USB port,
4059 then the battery is being charged at a 'trickle' rate.
4062 <emphasis>There are no “dit-dah-dah-dit” sound or lights like the manual
4063 mentions?</emphasis><?linebreak?>
4064 That's the “pad” mode. Weak batteries might be the problem.
4065 It is also possible that the flight computer is horizontal and the
4067 is instead a “dit-dit” meaning 'idle'. For TeleMini, it's possible that
4068 it received a command packet which would have left it in “pad” mode.
4071 <emphasis>How do I save flight data?</emphasis><?linebreak?>
4072 Live telemetry is written to file(s) whenever AltosUI is connected
4073 to the TeleDongle. The file area defaults to ~/TeleMetrum
4074 but is easily changed using the menus in AltosUI. The files that
4075 are written end in '.telem'. The after-flight
4076 data-dumped files will end in .eeprom and represent continuous data
4077 unlike the .telem files that are subject to losses
4078 along the RF data path.
4079 See the above instructions on what and how to save the eeprom stored
4080 data after physically retrieving your altimeter. Make sure to save
4081 the on-board data after each flight; while the TeleMetrum can store
4082 multiple flights, you never know when you'll lose the altimeter...
4086 <title>Notes for Older Software</title>
4089 Before AltosUI was written, using Altus Metrum devices required
4090 some finesse with the Linux command line. There was a limited
4091 GUI tool, ao-view, which provided functionality similar to the
4092 Monitor Flight window in AltosUI, but everything else was a
4093 fairly 80's experience. This appendix includes documentation for
4094 using that software.
4098 Both TeleMetrum and TeleDongle can be directly communicated
4099 with using USB ports. The first thing you should try after getting
4100 both units plugged into to your computer's USB port(s) is to run
4101 'ao-list' from a terminal-window to see what port-device-name each
4102 device has been assigned by the operating system.
4103 You will need this information to access the devices via their
4104 respective on-board firmware and data using other command line
4105 programs in the AltOS software suite.
4108 TeleMini can be communicated with through a TeleDongle device
4109 over the radio link. When first booted, TeleMini listens for a
4110 TeleDongle device and if it receives a packet, it goes into
4111 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be
4112 launched. The easiest way to get it talking is to start the
4113 communication link on the TeleDongle and the power up the
4117 To access the device's firmware for configuration you need a terminal
4118 program such as you would use to talk to a modem. The software
4119 authors prefer using the program 'cu' which comes from the UUCP package
4120 on most Unix-like systems such as Linux. An example command line for
4121 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
4122 indicated from running the
4123 ao-list program. Another reasonable terminal program for Linux is
4124 'cutecom'. The default 'escape'
4125 character used by CU (i.e. the character you use to
4126 issue commands to cu itself instead of sending the command as input
4127 to the connected device) is a '~'. You will need this for use in
4128 only two different ways during normal operations. First is to exit
4129 the program by sending a '~.' which is called a 'escape-disconnect'
4130 and allows you to close-out from 'cu'. The
4131 second use will be outlined later.
4134 All of the Altus Metrum devices share the concept of a two level
4135 command set in their firmware.
4136 The first layer has several single letter commands. Once
4137 you are using 'cu' (or 'cutecom') sending (typing) a '?'
4138 returns a full list of these
4139 commands. The second level are configuration sub-commands accessed
4140 using the 'c' command, for
4141 instance typing 'c?' will give you this second level of commands
4142 (all of which require the
4143 letter 'c' to access). Please note that most configuration options
4144 are stored only in Flash memory; TeleDongle doesn't provide any storage
4145 for these options and so they'll all be lost when you unplug it.
4148 Try setting these configuration ('c' or second level menu) values. A good
4149 place to start is by setting your call sign. By default, the boards
4150 use 'N0CALL' which is cute, but not exactly legal!
4151 Spend a few minutes getting comfortable with the units, their
4152 firmware, and 'cu' (or possibly 'cutecom').
4153 For instance, try to send
4154 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
4155 Verify you can connect and disconnect from the units while in your
4156 terminal program by sending the escape-disconnect mentioned above.
4159 To set the radio frequency, use the 'c R' command to specify the
4160 radio transceiver configuration parameter. This parameter is computed
4161 using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
4162 the standard calibration reference frequency, 'S', (normally 434.550MHz):
4166 Round the result to the nearest integer value.
4167 As with all 'c' sub-commands, follow this with a 'c w' to write the
4168 change to the parameter block in the on-board flash on
4169 your altimeter board if you want the change to stay in place across reboots.
4172 To set the apogee delay, use the 'c d' command.
4173 As with all 'c' sub-commands, follow this with a 'c w' to write the
4174 change to the parameter block in the on-board DataFlash chip.
4177 To set the main deployment altitude, use the 'c m' command.
4178 As with all 'c' sub-commands, follow this with a 'c w' to write the
4179 change to the parameter block in the on-board DataFlash chip.
4182 To calibrate the radio frequency, connect the UHF antenna port to a
4183 frequency counter, set the board to 434.550MHz, and use the 'C'
4184 command to generate a CW carrier. Wait for the transmitter temperature
4185 to stabilize and the frequency to settle down.
4186 Then, divide 434.550 MHz by the
4187 measured frequency and multiply by the current radio cal value show
4188 in the 'c s' command. For an unprogrammed board, the default value
4189 is 1186611. Take the resulting integer and program it using the 'c f'
4190 command. Testing with the 'C' command again should show a carrier
4191 within a few tens of Hertz of the intended frequency.
4192 As with all 'c' sub-commands, follow this with a 'c w' to write the
4193 change to the parameter block in the on-board DataFlash chip.
4196 Note that the 'reboot' command, which is very useful on the altimeters,
4197 will likely just cause problems with the dongle. The *correct* way
4198 to reset the dongle is just to unplug and re-plug it.
4201 A fun thing to do at the launch site and something you can do while
4202 learning how to use these units is to play with the radio link access
4203 between an altimeter and the TeleDongle. Be aware that you *must* create
4204 some physical separation between the devices, otherwise the link will
4205 not function due to signal overload in the receivers in each device.
4208 Now might be a good time to take a break and read the rest of this
4209 manual, particularly about the two “modes” that the altimeters
4210 can be placed in. TeleMetrum uses the position of the device when booting
4211 up will determine whether the unit is in “pad” or “idle” mode. TeleMini
4212 enters “idle” mode when it receives a command packet within the first 5 seconds
4213 of being powered up, otherwise it enters “pad” mode.
4216 You can access an altimeter in idle mode from the TeleDongle's USB
4217 connection using the radio link
4218 by issuing a 'p' command to the TeleDongle. Practice connecting and
4219 disconnecting ('~~' while using 'cu') from the altimeter. If
4220 you cannot escape out of the “p” command, (by using a '~~' when in
4221 CU) then it is likely that your kernel has issues. Try a newer version.
4224 Using this radio link allows you to configure the altimeter, test
4225 fire e-matches and igniters from the flight line, check pyro-match
4226 continuity and so forth. You can leave the unit turned on while it
4227 is in 'idle mode' and then place the
4228 rocket vertically on the launch pad, walk away and then issue a
4229 reboot command. The altimeter will reboot and start sending data
4230 having changed to the “pad” mode. If the TeleDongle is not receiving
4231 this data, you can disconnect 'cu' from the TeleDongle using the
4232 procedures mentioned above and THEN connect to the TeleDongle from
4233 inside 'ao-view'. If this doesn't work, disconnect from the
4234 TeleDongle, unplug it, and try again after plugging it back in.
4237 In order to reduce the chance of accidental firing of pyrotechnic
4238 charges, the command to fire a charge is intentionally somewhat
4239 difficult to type, and the built-in help is slightly cryptic to
4240 prevent accidental echoing of characters from the help text back at
4241 the board from firing a charge. The command to fire the apogee
4242 drogue charge is 'i DoIt drogue' and the command to fire the main
4243 charge is 'i DoIt main'.
4246 On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
4247 and 'ao-view' will both auditorily announce and visually indicate
4249 Now you can launch knowing that you have a good data path and
4250 good satellite lock for flight data and recovery. Remember
4251 you MUST tell ao-view to connect to the TeleDongle explicitly in
4252 order for ao-view to be able to receive data.
4255 The altimeters provide RDF (radio direction finding) tones on
4256 the pad, during descent and after landing. These can be used to
4257 locate the rocket using a directional antenna; the signal
4258 strength providing an indication of the direction from receiver to rocket.
4261 TeleMetrum also provides GPS tracking data, which can further simplify
4262 locating the rocket once it has landed. (The last good GPS data
4263 received before touch-down will be on the data screen of 'ao-view'.)
4266 Once you have recovered the rocket you can download the eeprom
4267 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
4268 either a USB cable or over the radio link using TeleDongle.
4269 And by following the man page for 'ao-postflight' you can create
4270 various data output reports, graphs, and even KML data to see the
4271 flight trajectory in Google-earth. (Moving the viewing angle making
4272 sure to connect the yellow lines while in Google-earth is the proper
4276 As for ao-view.... some things are in the menu but don't do anything
4277 very useful. The developers have stopped working on ao-view to focus
4278 on a new, cross-platform ground station program. So ao-view may or
4279 may not be updated in the future. Mostly you just use
4280 the Log and Device menus. It has a wonderful display of the incoming
4281 flight data and I am sure you will enjoy what it has to say to you
4282 once you enable the voice output!
4286 <title>Drill Templates</title>
4288 These images, when printed, provide precise templates for the
4289 mounting holes in Altus Metrum flight computers
4292 <title>TeleMega template</title>
4294 TeleMega has overall dimensions of 1.250 x 3.250 inches, and
4295 the mounting holes are sized for use with 4-40 or M3 screws.
4298 <mediaobject id="TeleMegaTemplate">
4300 <imagedata format="SVG" fileref="telemega-outline.svg"/>
4306 <title>TeleMetrum template</title>
4308 TeleMetrum has overall dimensions of 1.000 x 2.750 inches, and the
4309 mounting holes are sized for use with 4-40 or M3 screws.
4312 <mediaobject id="TeleMetrumTemplate">
4314 <imagedata format="SVG" fileref="telemetrum.svg"/>
4320 <title>TeleMini v2/EasyMini template</title>
4322 TeleMini v2 and EasyMini have overall dimensions of 0.800 x 1.500 inches, and the
4323 mounting holes are sized for use with 4-40 or M3 screws.
4326 <mediaobject id="MiniTemplate">
4328 <imagedata format="SVG" fileref="easymini-outline.svg"/>
4334 <title>TeleMini v1 template</title>
4336 TeleMini has overall dimensions of 0.500 x 1.500 inches, and the
4337 mounting holes are sized for use with 2-56 or M2 screws.
4340 <mediaobject id="TeleMiniTemplate">
4342 <imagedata format="SVG" fileref="telemini.svg"/>
4349 <title>Calibration</title>
4351 There are only two calibrations required for TeleMetrum and
4352 TeleMega, and only one for TeleDongle, TeleMini and EasyMini.
4353 All boards are shipped from the factory pre-calibrated, but
4354 the procedures are documented here in case they are ever
4355 needed. Re-calibration is not supported by AltosUI, you must
4356 connect to the board with a serial terminal program and
4357 interact directly with the on-board command interpreter to
4361 <title>Radio Frequency</title>
4363 The radio frequency is synthesized from a clock based on the
4364 crystal on the board. The actual frequency of this oscillator
4365 must be measured to generate a calibration constant. While our
4367 bandwidth is wide enough to allow boards to communicate even when
4368 their oscillators are not on exactly the same frequency, performance
4369 is best when they are closely matched.
4370 Radio frequency calibration requires a calibrated frequency counter.
4371 Fortunately, once set, the variation in frequency due to aging and
4372 temperature changes is small enough that re-calibration by customers
4373 should generally not be required.
4376 To calibrate the radio frequency, connect the UHF antenna
4377 port to a frequency counter, set the board to 434.550MHz,
4378 and use the 'C' command in the on-board command interpreter
4379 to generate a CW carrier. For USB-enabled boards, this is
4380 best done over USB. For TeleMini v1, note that the only way
4381 to escape the 'C' command is via power cycle since the board
4382 will no longer be listening for commands once it starts
4383 generating a CW carrier.
4386 Wait for the transmitter temperature to stabilize and the frequency
4387 to settle down. Then, divide 434.550 MHz by the
4388 measured frequency and multiply by the current radio cal value show
4389 in the 'c s' command. For an unprogrammed board, the default value
4390 is 1186611. Take the resulting integer and program it using the 'c f'
4391 command. Testing with the 'C' command again should show a carrier
4392 within a few tens of Hertz of the intended frequency.
4393 As with all 'c' sub-commands, follow this with a 'c w' to write the
4394 change to the parameter block in the on-board storage chip.
4397 Note that any time you re-do the radio frequency calibration, the
4398 radio frequency is reset to the default 434.550 Mhz. If you want
4399 to use another frequency, you will have to set that again after
4400 calibration is completed.
4404 <title>TeleMetrum and TeleMega Accelerometers</title>
4406 While barometric sensors are factory-calibrated,
4407 accelerometers are not, and so each must be calibrated once
4408 installed in a flight computer. Explicitly calibrating the
4409 accelerometers also allows us to load any compatible device.
4410 We perform a two-point calibration using gravity.
4413 To calibrate the acceleration sensor, use the 'c a 0' command. You
4414 will be prompted to orient the board vertically with the UHF antenna
4415 up and press a key, then to orient the board vertically with the
4416 UHF antenna down and press a key. Note that the accuracy of this
4417 calibration depends primarily on how perfectly vertical and still
4418 the board is held during the cal process. As with all 'c'
4419 sub-commands, follow this with a 'c w' to write the
4420 change to the parameter block in the on-board DataFlash chip.
4423 The +1g and -1g calibration points are included in each telemetry
4424 frame and are part of the header stored in onboard flash to be
4425 downloaded after flight. We always store and return raw ADC
4426 samples for each sensor... so nothing is permanently “lost” or
4427 “damaged” if the calibration is poor.
4430 In the unlikely event an accel cal goes badly, it is possible
4431 that TeleMetrum or TeleMega may always come up in 'pad mode'
4432 and as such not be listening to either the USB or radio link.
4433 If that happens, there is a special hook in the firmware to
4434 force the board back in to 'idle mode' so you can re-do the
4435 cal. To use this hook, you just need to ground the SPI clock
4436 pin at power-on. This pin is available as pin 2 on the 8-pin
4437 companion connector, and pin 1 is ground. So either
4438 carefully install a fine-gauge wire jumper between the two
4439 pins closest to the index hole end of the 8-pin connector, or
4440 plug in the programming cable to the 8-pin connector and use
4441 a small screwdriver or similar to short the two pins closest
4442 to the index post on the 4-pin end of the programming cable,
4443 and power up the board. It should come up in 'idle mode'
4444 (two beeps), allowing a re-cal.
4449 <title>Release Notes</title>
4451 <title>Version 1.3</title>
4453 xmlns:xi="http://www.w3.org/2001/XInclude"
4454 href="release-notes-1.3.xsl"
4455 xpointer="xpointer(/article/*)"/>
4458 <title>Version 1.2.1</title>
4460 xmlns:xi="http://www.w3.org/2001/XInclude"
4461 href="release-notes-1.2.1.xsl"
4462 xpointer="xpointer(/article/*)"/>
4465 <title>Version 1.2</title>
4467 xmlns:xi="http://www.w3.org/2001/XInclude"
4468 href="release-notes-1.2.xsl"
4469 xpointer="xpointer(/article/*)"/>
4472 <title>Version 1.1.1</title>
4474 xmlns:xi="http://www.w3.org/2001/XInclude"
4475 href="release-notes-1.1.1.xsl"
4476 xpointer="xpointer(/article/*)"/>
4479 <title>Version 1.1</title>
4481 xmlns:xi="http://www.w3.org/2001/XInclude"
4482 href="release-notes-1.1.xsl"
4483 xpointer="xpointer(/article/*)"/>
4486 <title>Version 1.0.1</title>
4488 xmlns:xi="http://www.w3.org/2001/XInclude"
4489 href="release-notes-1.0.1.xsl"
4490 xpointer="xpointer(/article/*)"/>
4493 <title>Version 0.9.2</title>
4495 xmlns:xi="http://www.w3.org/2001/XInclude"
4496 href="release-notes-0.9.2.xsl"
4497 xpointer="xpointer(/article/*)"/>
4500 <title>Version 0.9</title>
4502 xmlns:xi="http://www.w3.org/2001/XInclude"
4503 href="release-notes-0.9.xsl"
4504 xpointer="xpointer(/article/*)"/>
4507 <title>Version 0.8</title>
4509 xmlns:xi="http://www.w3.org/2001/XInclude"
4510 href="release-notes-0.8.xsl"
4511 xpointer="xpointer(/article/*)"/>
4514 <title>Version 0.7.1</title>
4516 xmlns:xi="http://www.w3.org/2001/XInclude"
4517 href="release-notes-0.7.1.xsl"
4518 xpointer="xpointer(/article/*)"/>
4523 <!-- LocalWords: Altusmetrum
projects / fw / altos / blob