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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>1.3.1</revnumber>
40 <date>21 January 2014</date>
42 Bug fixes for TeleMega and TeleMetrum v2.0 along with a few
43 small UI improvements.
47 <revnumber>1.3</revnumber>
48 <date>12 November 2013</date>
50 Updated for software version 1.3. Version 1.3 adds support
51 for TeleMega, TeleMetrum v2.0, TeleMini v2.0 and EasyMini
52 and fixes bugs in AltosUI and the AltOS firmware.
56 <revnumber>1.2.1</revnumber>
57 <date>21 May 2013</date>
59 Updated for software version 1.2. Version 1.2 adds support
60 for TeleBT and AltosDroid. It also adds a few minor features
61 and fixes bugs in AltosUI and the AltOS firmware.
65 <revnumber>1.2</revnumber>
66 <date>18 April 2013</date>
68 Updated for software version 1.2. Version 1.2 adds support
69 for MicroPeak and the MicroPeak USB interface.
73 <revnumber>1.1.1</revnumber>
74 <date>16 September 2012</date>
76 Updated for software version 1.1.1 Version 1.1.1 fixes a few
77 bugs found in version 1.1.
81 <revnumber>1.1</revnumber>
82 <date>13 September 2012</date>
84 Updated for software version 1.1. Version 1.1 has new
85 features but is otherwise compatible with version 1.0.
89 <revnumber>1.0</revnumber>
90 <date>24 August 2011</date>
92 Updated for software version 1.0. Note that 1.0 represents a
93 telemetry format change, meaning both ends of a link
94 (TeleMetrum/TeleMini and TeleDongle) must be updated or
95 communications will fail.
99 <revnumber>0.9</revnumber>
100 <date>18 January 2011</date>
102 Updated for software version 0.9. Note that 0.9 represents a
103 telemetry format change, meaning both ends of a link (TeleMetrum and
104 TeleDongle) must be updated or communications will fail.
108 <revnumber>0.8</revnumber>
109 <date>24 November 2010</date>
110 <revremark>Updated for software version 0.8 </revremark>
115 <title>Acknowledgments</title>
117 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing “The
118 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
119 Kit” which formed the basis of the original Getting Started chapter
120 in this manual. Bob was one of our first customers for a production
121 TeleMetrum, and his continued enthusiasm and contributions
122 are immensely gratifying and highly appreciated!
125 And thanks to Anthony (AJ) Towns for major contributions including
126 the AltosUI graphing and site map code and associated documentation.
127 Free software means that our customers and friends can become our
128 collaborators, and we certainly appreciate this level of
132 Have fun using these products, and we hope to meet all of you
133 out on the rocket flight line somewhere.
136 NAR #87103, TRA #12201
138 Keith Packard, KD7SQG
139 NAR #88757, TRA #12200
144 <title>Introduction and Overview</title>
146 Welcome to the Altus Metrum community! Our circuits and software reflect
147 our passion for both hobby rocketry and Free Software. We hope their
148 capabilities and performance will delight you in every way, but by
149 releasing all of our hardware and software designs under open licenses,
150 we also hope to empower you to take as active a role in our collective
154 The first device created for our community was TeleMetrum, a dual
155 deploy altimeter with fully integrated GPS and radio telemetry
156 as standard features, and a “companion interface” that will
157 support optional capabilities in the future. The latest version
158 of TeleMetrum, v2.0, has all of the same features but with
159 improved sensors and radio to offer increased performance.
162 Our second device was TeleMini, a dual deploy altimeter with
163 radio telemetry and radio direction finding. The first version
164 of this device was only 13mm by 38mm (½ inch by 1½ inches) and
165 could fit easily in an 18mm air-frame. The latest version, v2.0,
166 includes a beeper, USB data download and extended on-board
167 flight logging, along with an improved barometric sensor.
170 TeleMega is our most sophisticated device, including six pyro
171 channels (four of which are fully programmable), integrated GPS,
172 integrated gyroscopes for staging/air-start inhibit and high
173 performance telemetry.
176 EasyMini is a dual-deploy altimeter with logging and built-in
180 TeleDongle was our first ground station, providing a USB to RF
181 interfaces for communicating with the altimeters. Combined with
182 your choice of antenna and notebook computer, TeleDongle and our
183 associated user interface software form a complete ground
184 station capable of logging and displaying in-flight telemetry,
185 aiding rocket recovery, then processing and archiving flight
186 data for analysis and review.
189 For a slightly more portable ground station experience that also
190 provides direct rocket recovery support, TeleBT offers flight
191 monitoring and data logging using a Bluetooth™ connection between
192 the receiver and an Android device that has the AltosDroid
193 application installed from the Google Play store.
196 More products will be added to the Altus Metrum family over time, and
197 we currently envision that this will be a single, comprehensive manual
198 for the entire product family.
202 <title>Getting Started</title>
204 The first thing to do after you check the inventory of parts in your
205 “starter kit” is to charge the battery.
208 For TeleMetrum and TeleMega, the battery can be charged by plugging it into the
209 corresponding socket of the device and then using the USB
210 cable to plug the flight computer into your computer's USB socket. The
211 on-board circuitry will charge the battery whenever it is plugged
212 in, because the on-off switch does NOT control the
216 On TeleMetrum v1 boards, when the GPS chip is initially
217 searching for satellites, TeleMetrum will consume more current
218 than it pulls from the USB port, so the battery must be
219 attached in order to get satellite lock. Once GPS is locked,
220 the current consumption goes back down enough to enable charging
221 while running. So it's a good idea to fully charge the battery
222 as your first item of business so there is no issue getting and
223 maintaining satellite lock. The yellow charge indicator led
224 will go out when the battery is nearly full and the charger goes
225 to trickle charge. It can take several hours to fully recharge a
226 deeply discharged battery.
229 TeleMetrum v2.0 and TeleMega use a higher power battery charger,
230 allowing them to charge the battery while running the board at
231 maximum power. When the battery is charging, or when the board
232 is consuming a lot of power, the red LED will be lit. When the
233 battery is fully charged, the green LED will be lit. When the
234 battery is damaged or missing, both LEDs will be lit, which
238 The Lithium Polymer TeleMini and EasyMini battery can be charged by
239 disconnecting it from the board and plugging it into a
240 standalone battery charger such as the LipoCharger product
241 included in TeleMini Starter Kits, and connecting that via a USB
242 cable to a laptop or other USB power source.
245 You can also choose to use another battery with TeleMini v2.0
246 and EasyMini, anything supplying between 4 and 12 volts should
247 work fine (like a standard 9V battery), but if you are planning
248 to fire pyro charges, ground testing is required to verify that
249 the battery supplies enough current to fire your chosen e-matches.
252 The other active device in the starter kit is the TeleDongle USB to
253 RF interface. If you plug it in to your Mac or Linux computer it should
254 “just work”, showing up as a serial port device. Windows systems need
255 driver information that is part of the AltOS download to know that the
256 existing USB modem driver will work. We therefore recommend installing
257 our software before plugging in TeleDongle if you are using a Windows
258 computer. If you are using an older version of Linux and are having
259 problems, try moving to a fresher kernel (2.6.33 or newer).
262 Next you should obtain and install the AltOS software. The AltOS
263 distribution includes the AltosUI ground station program, current
265 images for all of the hardware, and a number of standalone
266 utilities that are rarely needed. Pre-built binary packages are
267 available for Linux, Microsoft Windows, and recent MacOSX
268 versions. Full source code and build instructions are also
269 available. The latest version may always be downloaded from
270 <ulink url="http://altusmetrum.org/AltOS"/>.
273 If you're using a TeleBT instead of the TeleDongle, you'll want to
274 install the AltosDroid application from the Google Play store on an
275 Android device. You don't need a data plan to use AltosDroid, but
276 without network access, the Map view will be less useful as it
277 won't contain any map data. You can also use TeleBT connected
278 over USB with your laptop computer; it acts exactly like a
279 TeleDongle. Anywhere this manual talks about TeleDongle, you can
280 also read that as 'and TeleBT when connected via USB'.
284 <title>Handling Precautions</title>
286 All Altus Metrum products are sophisticated electronic devices.
287 When handled gently and properly installed in an air-frame, they
288 will deliver impressive results. However, as with all electronic
289 devices, there are some precautions you must take.
292 The Lithium Polymer rechargeable batteries have an
293 extraordinary power density. This is great because we can fly with
294 much less battery mass than if we used alkaline batteries or previous
295 generation rechargeable batteries... but if they are punctured
296 or their leads are allowed to short, they can and will release their
298 Thus we recommend that you take some care when handling our batteries
299 and consider giving them some extra protection in your air-frame. We
300 often wrap them in suitable scraps of closed-cell packing foam before
301 strapping them down, for example.
304 The barometric sensors used on all of our flight computers are
305 sensitive to sunlight. In normal mounting situations, the baro sensor
306 and all of the other surface mount components
307 are “down” towards whatever the underlying mounting surface is, so
308 this is not normally a problem. Please consider this when designing an
309 installation in an air-frame with a see-through plastic payload bay. It
310 is particularly important to
311 consider this with TeleMini v1.0, both because the baro sensor is on the
312 “top” of the board, and because many model rockets with payload bays
313 use clear plastic for the payload bay! Replacing these with an opaque
314 cardboard tube, painting them, or wrapping them with a layer of masking
315 tape are all reasonable approaches to keep the sensor out of direct
319 The barometric sensor sampling port must be able to “breathe”,
320 both by not being covered by foam or tape or other materials that might
321 directly block the hole on the top of the sensor, and also by having a
322 suitable static vent to outside air.
325 As with all other rocketry electronics, Altus Metrum altimeters must
326 be protected from exposure to corrosive motor exhaust and ejection
331 <title>Altus Metrum Hardware</title>
333 <title>Overview</title>
335 Here's the full set of Altus Metrum products, both in
336 production and retired.
339 <title>Altus Metrum Electronics</title>
340 <?dbfo keep-together="always"?>
341 <tgroup cols='8' align='center' colsep='1' rowsep='1'>
342 <colspec align='center' colwidth='*' colname='Device'/>
343 <colspec align='center' colwidth='*' colname='Barometer'/>
344 <colspec align='center' colwidth='*' colname='Z-axis accelerometer'/>
345 <colspec align='center' colwidth='*' colname='GPS'/>
346 <colspec align='center' colwidth='*' colname='3D sensors'/>
347 <colspec align='center' colwidth='*' colname='Storage'/>
348 <colspec align='center' colwidth='*' colname='RF'/>
349 <colspec align='center' colwidth='*' colname='Battery'/>
352 <entry align='center'>Device</entry>
353 <entry align='center'>Barometer</entry>
354 <entry align='center'>Z-axis accelerometer</entry>
355 <entry align='center'>GPS</entry>
356 <entry align='center'>3D sensors</entry>
357 <entry align='center'>Storage</entry>
358 <entry align='center'>RF Output</entry>
359 <entry align='center'>Battery</entry>
364 <entry>TeleMetrum v1.0</entry>
365 <entry><para>MP3H6115 10km (33k')</para></entry>
366 <entry><para>MMA2202 50g</para></entry>
367 <entry>SkyTraq</entry>
374 <entry>TeleMetrum v1.1</entry>
375 <entry><para>MP3H6115 10km (33k')</para></entry>
376 <entry><para>MMA2202 50g</para></entry>
377 <entry>SkyTraq</entry>
384 <entry>TeleMetrum v1.2</entry>
385 <entry><para>MP3H6115 10km (33k')</para></entry>
386 <entry><para>ADXL78 70g</para></entry>
387 <entry>SkyTraq</entry>
394 <entry>TeleMetrum v2.0</entry>
395 <entry><para>MS5607 30km (100k')</para></entry>
396 <entry><para>MMA6555 102g</para></entry>
397 <entry>uBlox Max-7Q</entry>
404 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
405 <entry><para>MP3H6115 10km (33k')</para></entry>
414 <entry>TeleMini <?linebreak?>v2.0</entry>
415 <entry><para>MS5607 30km (100k')</para></entry>
421 <entry>3.7-12V</entry>
424 <entry>EasyMini <?linebreak?>v1.0</entry>
425 <entry><para>MS5607 30km (100k')</para></entry>
431 <entry>3.7-12V</entry>
434 <entry>TeleMega <?linebreak?>v1.0</entry>
435 <entry><para>MS5607 30km (100k')</para></entry>
436 <entry><para>MMA6555 102g</para></entry>
437 <entry>uBlox Max-7Q</entry>
438 <entry><para>MPU6000 HMC5883</para></entry>
447 <title>Altus Metrum Boards</title>
448 <?dbfo keep-together="always"?>
449 <tgroup cols='6' align='center' colsep='1' rowsep='1'>
450 <colspec align='center' colwidth='*' colname='Device'/>
451 <colspec align='center' colwidth='*' colname='Connectors'/>
452 <colspec align='center' colwidth='*' colname='Screw Terminals'/>
453 <colspec align='center' colwidth='*' colname='Width'/>
454 <colspec align='center' colwidth='*' colname='Length'/>
455 <colspec align='center' colwidth='*' colname='Tube Size'/>
458 <entry align='center'>Device</entry>
459 <entry align='center'>Connectors</entry>
460 <entry align='center'>Screw Terminals</entry>
461 <entry align='center'>Width</entry>
462 <entry align='center'>Length</entry>
463 <entry align='center'>Tube Size</entry>
468 <entry>TeleMetrum</entry>
472 Companion<?linebreak?>
476 <entry><para>Apogee pyro <?linebreak?>Main pyro <?linebreak?>Switch</para></entry>
477 <entry>1 inch (2.54cm)</entry>
478 <entry>2 ¾ inch (6.99cm)</entry>
479 <entry>29mm coupler</entry>
482 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
489 Apogee pyro <?linebreak?>
492 <entry>½ inch (1.27cm)</entry>
493 <entry>1½ inch (3.81cm)</entry>
494 <entry>18mm coupler</entry>
497 <entry>TeleMini <?linebreak?>v2.0</entry>
505 Apogee pyro <?linebreak?>
506 Main pyro <?linebreak?>
507 Battery <?linebreak?>
510 <entry>0.8 inch (2.03cm)</entry>
511 <entry>1½ inch (3.81cm)</entry>
512 <entry>24mm coupler</entry>
515 <entry>EasyMini</entry>
522 Apogee pyro <?linebreak?>
523 Main pyro <?linebreak?>
524 Battery <?linebreak?>
527 <entry>0.8 inch (2.03cm)</entry>
528 <entry>1½ inch (3.81cm)</entry>
529 <entry>24mm coupler</entry>
532 <entry>TeleMega</entry>
536 Companion<?linebreak?>
541 Apogee pyro <?linebreak?>
542 Main pyro<?linebreak?>
543 Pyro A-D<?linebreak?>
547 <entry>1¼ inch (3.18cm)</entry>
548 <entry>3¼ inch (8.26cm)</entry>
549 <entry>38mm coupler</entry>
556 <title>TeleMetrum</title>
560 <imagedata fileref="telemetrum-v1.1-thside.jpg" width="5.5in" scalefit="1"/>
565 TeleMetrum is a 1 inch by 2¾ inch circuit board. It was designed to
566 fit inside coupler for 29mm air-frame tubing, but using it in a tube that
567 small in diameter may require some creativity in mounting and wiring
568 to succeed! The presence of an accelerometer means TeleMetrum should
569 be aligned along the flight axis of the airframe, and by default the ¼
570 wave UHF wire antenna should be on the nose-cone end of the board. The
571 antenna wire is about 7 inches long, and wiring for a power switch and
572 the e-matches for apogee and main ejection charges depart from the
573 fin can end of the board, meaning an ideal “simple” avionics
574 bay for TeleMetrum should have at least 10 inches of interior length.
578 <title>TeleMini</title>
582 <imagedata fileref="telemini-v1-top.jpg" width="5.5in" scalefit="1"/>
587 TeleMini v1.0 is ½ inches by 1½ inches. It was
588 designed to fit inside an 18mm air-frame tube, but using it in
589 a tube that small in diameter may require some creativity in
590 mounting and wiring to succeed! Since there is no
591 accelerometer, TeleMini can be mounted in any convenient
592 orientation. The default ¼ wave UHF wire antenna attached to
593 the center of one end of the board is about 7 inches long. Two
594 wires for the power switch are connected to holes in the
595 middle of the board. Screw terminals for the e-matches for
596 apogee and main ejection charges depart from the other end of
597 the board, meaning an ideal “simple” avionics bay for TeleMini
598 should have at least 9 inches of interior length.
603 <imagedata fileref="telemini-v2-top.jpg" width="5.5in" scalefit="1"/>
608 TeleMini v2.0 is 0.8 inches by 1½ inches. It adds more
609 on-board data logging memory, a built-in USB connector and
610 screw terminals for the battery and power switch. The larger
611 board fits in a 24mm coupler. There's also a battery connector
612 for a LiPo battery if you want to use one of those.
616 <title>EasyMini</title>
620 <imagedata fileref="easymini-top.jpg" width="5.5in" scalefit="1"/>
625 EasyMini is built on a 0.8 inch by 1½ inch circuit board. It's
626 designed to fit in a 24mm coupler tube. The connectors and
627 screw terminals match TeleMini v2.0, so you can easily swap between
628 EasyMini and TeleMini.
632 <title>TeleMega</title>
636 <imagedata fileref="telemega-v1.0-top.jpg" width="5.5in" scalefit="1"/>
641 TeleMega is a 1¼ inch by 3¼ inch circuit board. It was
642 designed to easily fit in a 38mm coupler. Like TeleMetrum,
643 TeleMega has an accelerometer and so it must be mounted so that
644 the board is aligned with the flight axis. It can be mounted
645 either antenna up or down.
649 <title>Flight Data Recording</title>
651 Each flight computer logs data at 100 samples per second
652 during ascent and 10 samples per second during descent, except
653 for TeleMini v1.0, which records ascent at 10 samples per
654 second and descent at 1 sample per second. Data are logged to
655 an on-board flash memory part, which can be partitioned into
656 several equal-sized blocks, one for each flight.
659 <title>Data Storage on Altus Metrum altimeters</title>
660 <?dbfo keep-together="always"?>
661 <tgroup cols='4' align='center' colsep='1' rowsep='1'>
662 <colspec align='center' colwidth='*' colname='Device'/>
663 <colspec align='center' colwidth='*' colname='Bytes per sample'/>
664 <colspec align='center' colwidth='*' colname='Total storage'/>
665 <colspec align='center' colwidth='*' colname='Minutes of
669 <entry align='center'>Device</entry>
670 <entry align='center'>Bytes per Sample</entry>
671 <entry align='center'>Total Storage</entry>
672 <entry align='center'>Minutes at Full Rate</entry>
677 <entry>TeleMetrum v1.0</entry>
683 <entry>TeleMetrum v1.1 v1.2</entry>
689 <entry>TeleMetrum v2.0</entry>
695 <entry>TeleMini v1.0</entry>
701 <entry>TeleMini v2.0</entry>
707 <entry>EasyMini</entry>
713 <entry>TeleMega</entry>
722 The on-board flash is partitioned into separate flight logs,
723 each of a fixed maximum size. Increase the maximum size of
724 each log and you reduce the number of flights that can be
725 stored. Decrease the size and you can store more flights.
728 Configuration data is also stored in the flash memory on
729 TeleMetrum v1.x, TeleMini and EasyMini. This consumes 64kB
730 of flash space. This configuration space is not available
731 for storing flight log data. TeleMetrum v2.0 and TeleMega
732 store configuration data in a bit of eeprom available within
733 the processor chip, leaving that space available in flash for
737 To compute the amount of space needed for a single flight, you
738 can multiply the expected ascent time (in seconds) by 100
739 times bytes-per-sample, multiply the expected descent time (in
740 seconds) by 10 times the bytes per sample and add the two
741 together. That will slightly under-estimate the storage (in
742 bytes) needed for the flight. For instance, a TeleMetrum v2.0 flight spending
743 20 seconds in ascent and 150 seconds in descent will take
744 about (20 * 1600) + (150 * 160) = 56000 bytes of storage. You
745 could store dozens of these flights in the on-board flash.
748 The default size allows for several flights on each flight
749 computer, except for TeleMini v1.0, which only holds data for a
750 single flight. You can adjust the size.
753 Altus Metrum flight computers will not overwrite existing
754 flight data, so be sure to download flight data and erase it
755 from the flight computer before it fills up. The flight
756 computer will still successfully control the flight even if it
757 cannot log data, so the only thing you will lose is the data.
761 <title>Installation</title>
763 A typical installation involves attaching
764 only a suitable battery, a single pole switch for
765 power on/off, and two pairs of wires connecting e-matches for the
766 apogee and main ejection charges. All Altus Metrum products are
767 designed for use with single-cell batteries with 3.7 volts
768 nominal. TeleMini v2.0 and EasyMini may also be used with other
769 batteries as long as they supply between 4 and 12 volts.
772 The battery connectors are a standard 2-pin JST connector and
773 match batteries sold by Spark Fun. These batteries are
774 single-cell Lithium Polymer batteries that nominally provide 3.7
775 volts. Other vendors sell similar batteries for RC aircraft
776 using mating connectors, however the polarity for those is
777 generally reversed from the batteries used by Altus Metrum
778 products. In particular, the Tenergy batteries supplied for use
779 in Featherweight flight computers are not compatible with Altus
780 Metrum flight computers or battery chargers. <emphasis>Check
781 polarity and voltage before connecting any battery not purchased
782 from Altus Metrum or Spark Fun.</emphasis>
785 By default, we use the unregulated output of the battery directly
786 to fire ejection charges. This works marvelously with standard
787 low-current e-matches like the J-Tek from MJG Technologies, and with
788 Quest Q2G2 igniters. However, if you want or need to use a separate
789 pyro battery, check out the “External Pyro Battery” section in this
790 manual for instructions on how to wire that up. The altimeters are
791 designed to work with an external pyro battery of no more than 15 volts.
795 Ejection charges are wired directly to the screw terminal block
796 at the aft end of the altimeter. You'll need a very small straight
797 blade screwdriver for these screws, such as you might find in a
798 jeweler's screwdriver set.
801 Except for TeleMini v1.0, the flight computers also use the
802 screw terminal block for the power switch leads. On TeleMini v1.0,
803 the power switch leads are soldered directly to the board and
804 can be connected directly to a switch.
807 For most air-frames, the integrated antennas are more than
808 adequate. However, if you are installing in a carbon-fiber or
809 metal electronics bay which is opaque to RF signals, you may need to
810 use off-board external antennas instead. In this case, you can
811 replace the stock UHF antenna wire with an edge-launched SMA connector,
812 and, on TeleMetrum v1, you can unplug the integrated GPS
813 antenna and select an appropriate off-board GPS antenna with
814 cable terminating in a U.FL connector.
819 <title>System Operation</title>
821 <title>Firmware Modes </title>
823 The AltOS firmware build for the altimeters has two
824 fundamental modes, “idle” and “flight”. Which of these modes
825 the firmware operates in is determined at start up time. For
826 TeleMetrum and TeleMega, which have accelerometers, the mode is
827 controlled by the orientation of the
828 rocket (well, actually the board, of course...) at the time
829 power is switched on. If the rocket is “nose up”, then
830 the flight computer assumes it's on a rail or rod being prepared for
831 launch, so the firmware chooses flight mode. However, if the
832 rocket is more or less horizontal, the firmware instead enters
833 idle mode. Since TeleMini v2.0 and EasyMini don't have an
834 accelerometer we can use to determine orientation, “idle” mode
835 is selected if the board is connected via USB to a computer,
836 otherwise the board enters “flight” mode. TeleMini v1.0
837 selects “idle” mode if it receives a command packet within the
838 first five seconds of operation.
841 At power on, you will hear three beeps or see three flashes
842 (“S” in Morse code for start up) and then a pause while
843 the altimeter completes initialization and self test, and decides
844 which mode to enter next.
847 Here's a short summary of all of the modes and the beeping (or
848 flashing, in the case of TeleMini v1) that accompanies each
849 mode. In the description of the beeping pattern, “dit” means a
850 short beep while "dah" means a long beep (three times as
851 long). “Brap” means a long dissonant tone.
853 <title>AltOS Modes</title>
854 <?dbfo keep-together="always"?>
855 <tgroup cols='4' align='center' colsep='1' rowsep='1'>
856 <colspec align='center' colwidth='*' colname='Mode Name'/>
857 <colspec align='center' colwidth='*' colname='Letter'/>
858 <colspec align='center' colwidth='*' colname='Beeps'/>
859 <colspec align='center' colwidth='*' colname='Description'/>
862 <entry>Mode Name</entry>
863 <entry>Abbreviation</entry>
865 <entry>Description</entry>
870 <entry>Startup</entry>
872 <entry>dit dit dit</entry>
875 Calibrating sensors, detecting orientation.
882 <entry>dit dit</entry>
885 Ready to accept commands over USB or radio link.
892 <entry>dit dah dah dit</entry>
895 Waiting for launch. Not listening for commands.
902 <entry>dah dit dit dit</entry>
905 Accelerating upwards.
912 <entry>dit dit dah dit</entry>
915 Decellerating, but moving faster than 200m/s.
922 <entry>dah dit dah dit</entry>
925 Decellerating, moving slower than 200m/s
930 <entry>Drogue</entry>
932 <entry>dah dit dit</entry>
935 Descending after apogee. Above main height.
942 <entry>dah dah</entry>
945 Descending. Below main height.
950 <entry>Landed</entry>
952 <entry>dit dah dit dit</entry>
955 Stable altitude for at least ten seconds.
960 <entry>Sensor error</entry>
962 <entry>dah dit dit dah</entry>
965 Error detected during sensor calibration.
974 In flight or “pad” mode, the altimeter engages the flight
975 state machine, goes into transmit-only mode to send telemetry,
976 and waits for launch to be detected. Flight mode is indicated
977 by an “di-dah-dah-dit” (“P” for pad) on the beeper or lights,
978 followed by beeps or flashes indicating the state of the
979 pyrotechnic igniter continuity. One beep/flash indicates
980 apogee continuity, two beeps/flashes indicate main continuity,
981 three beeps/flashes indicate both apogee and main continuity,
982 and one longer “brap” sound which is made by rapidly
983 alternating between two tones indicates no continuity. For a
984 dual deploy flight, make sure you're getting three beeps or
985 flashes before launching! For apogee-only or motor eject
986 flights, do what makes sense.
989 If idle mode is entered, you will hear an audible “di-dit” or
990 see two short flashes (“I” for idle), and the flight state
991 machine is disengaged, thus no ejection charges will fire.
992 The altimeters also listen for the radio link when in idle
993 mode for requests sent via TeleDongle. Commands can be issued
994 in idle mode over either USB or the radio link
995 equivalently. TeleMini v1.0 only has the radio link. Idle
996 mode is useful for configuring the altimeter, for extracting
997 data from the on-board storage chip after flight, and for
998 ground testing pyro charges.
1001 In “Idle” and “Pad” modes, once the mode indication
1002 beeps/flashes and continuity indication has been sent, if
1003 there is no space available to log the flight in on-board
1004 memory, the flight computer will emit a warbling tone (much
1005 slower than the “no continuity tone”)
1008 Here's a summary of all of the “pad” and “idle” mode indications.
1010 <title>Pad/Idle Indications</title>
1011 <?dbfo keep-together="always"?>
1012 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
1013 <colspec align='center' colwidth='*' colname='Name'/>
1014 <colspec align='center' colwidth='*' colname='Beeps'/>
1015 <colspec align='center' colwidth='*' colname='Description'/>
1019 <entry>Beeps</entry>
1020 <entry>Description</entry>
1025 <entry>Neither</entry>
1029 No continuity detected on either apogee or main
1035 <entry>Apogee</entry>
1039 Continuity detected only on apogee igniter.
1045 <entry>dit dit</entry>
1048 Continuity detected only on main igniter.
1054 <entry>dit dit dit</entry>
1057 Continuity detected on both igniters.
1062 <entry>Storage Full</entry>
1063 <entry>warble</entry>
1066 On-board data logging storage is full. This will
1067 not prevent the flight computer from safely
1068 controlling the flight or transmitting telemetry
1069 signals, but no record of the flight will be
1070 stored in on-board flash.
1079 Once landed, the flight computer will signal that by emitting
1080 the “Landed” sound described above, after which it will beep
1081 out the apogee height (in meters). Each digit is represented
1082 by a sequence of short “dit” beeps, with a pause between
1083 digits. A zero digit is represented with one long “dah”
1084 beep. The flight computer will continue to report landed mode
1085 and beep out the maximum height until turned off.
1088 One “neat trick” of particular value when TeleMetrum or TeleMega are used with
1089 very large air-frames, is that you can power the board up while the
1090 rocket is horizontal, such that it comes up in idle mode. Then you can
1091 raise the air-frame to launch position, and issue a 'reset' command
1092 via TeleDongle over the radio link to cause the altimeter to reboot and
1093 come up in flight mode. This is much safer than standing on the top
1094 step of a rickety step-ladder or hanging off the side of a launch
1095 tower with a screw-driver trying to turn on your avionics before
1096 installing igniters!
1099 TeleMini v1.0 is configured solely via the radio link. Of course, that
1100 means you need to know the TeleMini radio configuration values
1101 or you won't be able to communicate with it. For situations
1102 when you don't have the radio configuration values, TeleMini v1.0
1103 offers an 'emergency recovery' mode. In this mode, TeleMini is
1104 configured as follows:
1108 Sets the radio frequency to 434.550MHz
1113 Sets the radio calibration back to the factory value.
1118 Sets the callsign to N0CALL
1123 Does not go to 'pad' mode after five seconds.
1129 To get into 'emergency recovery' mode, first find the row of
1130 four small holes opposite the switch wiring. Using a short
1131 piece of small gauge wire, connect the outer two holes
1132 together, then power TeleMini up. Once the red LED is lit,
1133 disconnect the wire and the board should signal that it's in
1134 'idle' mode after the initial five second startup period.
1140 TeleMetrum and TeleMega include a complete GPS receiver. A
1141 complete explanation of how GPS works is beyond the scope of
1142 this manual, but the bottom line is that the GPS receiver
1143 needs to lock onto at least four satellites to obtain a solid
1144 3 dimensional position fix and know what time it is.
1147 The flight computers provide backup power to the GPS chip any time a
1148 battery is connected. This allows the receiver to “warm start” on
1149 the launch rail much faster than if every power-on were a GPS
1150 “cold start”. In typical operations, powering up
1151 on the flight line in idle mode while performing final air-frame
1152 preparation will be sufficient to allow the GPS receiver to cold
1153 start and acquire lock. Then the board can be powered down during
1154 RSO review and installation on a launch rod or rail. When the board
1155 is turned back on, the GPS system should lock very quickly, typically
1156 long before igniter installation and return to the flight line are
1161 <title>Controlling An Altimeter Over The Radio Link</title>
1163 One of the unique features of the Altus Metrum system is the
1164 ability to create a two way command link between TeleDongle
1165 and an altimeter using the digital radio transceivers
1166 built into each device. This allows you to interact with the
1167 altimeter from afar, as if it were directly connected to the
1171 Any operation which can be performed with a flight computer can
1172 either be done with the device directly connected to the
1173 computer via the USB cable, or through the radio
1174 link. TeleMini v1.0 doesn't provide a USB connector and so it is
1175 always communicated with over radio. Select the appropriate
1176 TeleDongle device when the list of devices is presented and
1177 AltosUI will interact with an altimeter over the radio link.
1180 One oddity in the current interface is how AltosUI selects the
1181 frequency for radio communications. Instead of providing
1182 an interface to specifically configure the frequency, it uses
1183 whatever frequency was most recently selected for the target
1184 TeleDongle device in Monitor Flight mode. If you haven't ever
1185 used that mode with the TeleDongle in question, select the
1186 Monitor Flight button from the top level UI, and pick the
1187 appropriate TeleDongle device. Once the flight monitoring
1188 window is open, select the desired frequency and then close it
1189 down again. All radio communications will now use that frequency.
1194 Save Flight Data—Recover flight data from the rocket without
1200 Configure altimeter apogee delays, main deploy heights
1201 and additional pyro event conditions
1202 to respond to changing launch conditions. You can also
1203 'reboot' the altimeter. Use this to remotely enable the
1204 flight computer by turning TeleMetrum or TeleMega on in “idle” mode,
1205 then once the air-frame is oriented for launch, you can
1206 reboot the altimeter and have it restart in pad mode
1207 without having to climb the scary ladder.
1212 Fire Igniters—Test your deployment charges without snaking
1213 wires out through holes in the air-frame. Simply assemble the
1214 rocket as if for flight with the apogee and main charges
1215 loaded, then remotely command the altimeter to fire the
1221 Operation over the radio link for configuring an altimeter, ground
1222 testing igniters, and so forth uses the same RF frequencies as flight
1223 telemetry. To configure the desired TeleDongle frequency, select
1224 the monitor flight tab, then use the frequency selector and
1225 close the window before performing other desired radio operations.
1228 The flight computers only enable radio commanding in 'idle' mode.
1229 TeleMetrum and TeleMega use the accelerometer to detect which orientation they
1230 start up in, so make sure you have the flight computer lying horizontally when you turn
1231 it on. Otherwise, it will start in 'pad' mode ready for
1232 flight, and will not be listening for command packets from TeleDongle.
1235 TeleMini listens for a command packet for five seconds after
1236 first being turned on, if it doesn't hear anything, it enters
1237 'pad' mode, ready for flight and will no longer listen for
1238 command packets. The easiest way to connect to TeleMini is to
1239 initiate the command and select the TeleDongle device. At this
1240 point, the TeleDongle will be attempting to communicate with
1241 the TeleMini. Now turn TeleMini on, and it should immediately
1242 start communicating with the TeleDongle and the desired
1243 operation can be performed.
1246 You can monitor the operation of the radio link by watching the
1247 lights on the devices. The red LED will flash each time a packet
1248 is transmitted, while the green LED will light up on TeleDongle when
1249 it is waiting to receive a packet from the altimeter.
1253 <title>Ground Testing </title>
1255 An important aspect of preparing a rocket using electronic deployment
1256 for flight is ground testing the recovery system. Thanks
1257 to the bi-directional radio link central to the Altus Metrum system,
1258 this can be accomplished in a TeleMega, TeleMetrum or TeleMini equipped rocket
1259 with less work than you may be accustomed to with other systems. It
1263 Just prep the rocket for flight, then power up the altimeter
1264 in “idle” mode (placing air-frame horizontal for TeleMetrum or TeleMega, or
1265 selecting the Configure Altimeter tab for TeleMini). This will cause
1266 the firmware to go into “idle” mode, in which the normal flight
1267 state machine is disabled and charges will not fire without
1268 manual command. You can now command the altimeter to fire the apogee
1269 or main charges from a safe distance using your computer and
1270 TeleDongle and the Fire Igniter tab to complete ejection testing.
1274 <title>Radio Link </title>
1276 Our flight computers all incorporate an RF transceiver, but
1277 it's not a full duplex system... each end can only be transmitting or
1278 receiving at any given moment. So we had to decide how to manage the
1282 By design, the altimeter firmware listens for the radio link when
1283 it's in “idle mode”, which
1284 allows us to use the radio link to configure the rocket, do things like
1285 ejection tests, and extract data after a flight without having to
1286 crack open the air-frame. However, when the board is in “flight
1287 mode”, the altimeter only
1288 transmits and doesn't listen at all. That's because we want to put
1289 ultimate priority on event detection and getting telemetry out of
1291 the radio in case the rocket crashes and we aren't able to extract
1295 We don't generally use a 'normal packet radio' mode like APRS
1296 because they're just too inefficient. The GFSK modulation we
1297 use is FSK with the base-band pulses passed through a Gaussian
1298 filter before they go into the modulator to limit the
1299 transmitted bandwidth. When combined with forward error
1300 correction and interleaving, this allows us to have a very
1301 robust 19.2 kilobit data link with only 10-40 milliwatts of
1302 transmit power, a whip antenna in the rocket, and a hand-held
1303 Yagi on the ground. We've had flights to above 21k feet AGL
1304 with great reception, and calculations suggest we should be
1305 good to well over 40k feet AGL with a 5-element yagi on the
1306 ground with our 10mW units and over 100k feet AGL with the
1307 40mW devices. We hope to fly boards to higher altitudes over
1308 time, and would of course appreciate customer feedback on
1309 performance in higher altitude flights!
1312 TeleMetrum v2.0 and TeleMega can send APRS if desired, and the
1313 interval between APRS packets can be configured. As each APRS
1314 packet takes a full second to transmit, we recommend an
1315 interval of at least 5 seconds to avoid consuming too much
1316 battery power or radio channel bandwidth.
1320 <title>Configurable Parameters</title>
1322 Configuring an Altus Metrum altimeter for flight is very
1323 simple. Even on our baro-only TeleMini and EasyMini boards, the use of a Kalman
1324 filter means there is no need to set a “mach delay”. The few
1325 configurable parameters can all be set using AltosUI over USB or
1326 or radio link via TeleDongle.
1329 <title>Radio Frequency</title>
1331 Altus Metrum boards support radio frequencies in the 70cm
1332 band. By default, the configuration interface provides a
1333 list of 10 “standard” frequencies in 100kHz channels starting at
1334 434.550MHz. However, the firmware supports use of
1335 any 50kHz multiple within the 70cm band. At any given
1336 launch, we highly recommend coordinating when and by whom each
1337 frequency will be used to avoid interference. And of course, both
1338 altimeter and TeleDongle must be configured to the same
1339 frequency to successfully communicate with each other.
1343 <title>Apogee Delay</title>
1345 Apogee delay is the number of seconds after the altimeter detects flight
1346 apogee that the drogue charge should be fired. In most cases, this
1347 should be left at the default of 0. However, if you are flying
1348 redundant electronics such as for an L3 certification, you may wish
1349 to set one of your altimeters to a positive delay so that both
1350 primary and backup pyrotechnic charges do not fire simultaneously.
1353 The Altus Metrum apogee detection algorithm fires exactly at
1354 apogee. If you are also flying an altimeter like the
1355 PerfectFlite MAWD, which only supports selecting 0 or 1
1356 seconds of apogee delay, you may wish to set the MAWD to 0
1357 seconds delay and set the TeleMetrum to fire your backup 2
1358 or 3 seconds later to avoid any chance of both charges
1359 firing simultaneously. We've flown several air-frames this
1360 way quite happily, including Keith's successful L3 cert.
1364 <title>Main Deployment Altitude</title>
1366 By default, the altimeter will fire the main deployment charge at an
1367 elevation of 250 meters (about 820 feet) above ground. We think this
1368 is a good elevation for most air-frames, but feel free to change this
1369 to suit. In particular, if you are flying two altimeters, you may
1371 deployment elevation for the backup altimeter to be something lower
1372 than the primary so that both pyrotechnic charges don't fire
1377 <title>Maximum Flight Log</title>
1379 Changing this value will set the maximum amount of flight
1380 log storage that an individual flight will use. The
1381 available storage is divided into as many flights of the
1382 specified size as can fit in the available space. You can
1383 download and erase individual flight logs. If you fill up
1384 the available storage, future flights will not get logged
1385 until you erase some of the stored ones.
1388 Even though our flight computers (except TeleMini v1.0) can store
1389 multiple flights, we strongly recommend downloading and saving
1390 flight data after each flight.
1394 <title>Ignite Mode</title>
1396 Instead of firing one charge at apogee and another charge at
1397 a fixed height above the ground, you can configure the
1398 altimeter to fire both at apogee or both during
1399 descent. This was added to support an airframe Bdale designed that
1400 had two altimeters, one in the fin can and one in the nose.
1403 Providing the ability to use both igniters for apogee or
1404 main allows some level of redundancy without needing two
1405 flight computers. In Redundant Apogee or Redundant Main
1406 mode, the two charges will be fired two seconds apart.
1410 <title>Pad Orientation</title>
1412 TeleMetrum and TeleMega measure acceleration along the axis
1413 of the board. Which way the board is oriented affects the
1414 sign of the acceleration value. Instead of trying to guess
1415 which way the board is mounted in the air frame, the
1416 altimeter must be explicitly configured for either Antenna
1417 Up or Antenna Down. The default, Antenna Up, expects the end
1418 of the board connected to the 70cm antenna to be nearest the
1419 nose of the rocket, with the end containing the screw
1420 terminals nearest the tail.
1424 <title>Configurable Pyro Channels</title>
1426 In addition to the usual Apogee and Main pyro channels,
1427 TeleMega has four additional channels that can be configured
1428 to activate when various flight conditions are
1429 satisfied. You can select as many conditions as necessary;
1430 all of them must be met in order to activate the
1431 channel. The conditions available are:
1436 Acceleration away from the ground. Select a value, and
1437 then choose whether acceleration should be above or
1438 below that value. Acceleration is positive upwards, so
1439 accelerating towards the ground would produce negative
1440 numbers. Acceleration during descent is noisy and
1441 inaccurate, so be careful when using it during these
1442 phases of the flight.
1447 Vertical speed. Select a value, and then choose whether
1448 vertical speed should be above or below that
1449 value. Speed is positive upwards, so moving towards the
1450 ground would produce negative numbers. Speed during
1451 descent is a bit noisy and so be careful when using it
1452 during these phases of the flight.
1457 Height. Select a value, and then choose whether the
1458 height above the launch pad should be above or below
1464 Orientation. TeleMega contains a 3-axis gyroscope and
1465 accelerometer which is used to measure the current
1466 angle. Note that this angle is not the change in angle
1467 from the launch pad, but rather absolute relative to
1468 gravity; the 3-axis accelerometer is used to compute the
1469 angle of the rocket on the launch pad and initialize the
1470 system. Because this value is computed by integrating
1471 rate gyros, it gets progressively less accurate as the
1472 flight goes on. It should have an accumulated error of
1473 less than 0.2°/second (after 10 seconds of flight, the
1474 error should be less than 2°).
1477 The usual use of the orientation configuration is to
1478 ensure that the rocket is traveling mostly upwards when
1479 deciding whether to ignite air starts or additional
1480 stages. For that, choose a reasonable maximum angle
1481 (like 20°) and set the motor igniter to require an angle
1482 of less than that value.
1487 Flight Time. Time since boost was detected. Select a
1488 value and choose whether to activate the pyro channel
1489 before or after that amount of time.
1494 Ascending. A simple test saying whether the rocket is
1495 going up or not. This is exactly equivalent to testing
1496 whether the speed is > 0.
1501 Descending. A simple test saying whether the rocket is
1502 going down or not. This is exactly equivalent to testing
1503 whether the speed is < 0.
1508 After Motor. The flight software counts each time the
1509 rocket starts accelerating (presumably due to a motor or
1510 motors igniting). Use this value to count ignitions for
1511 multi-staged or multi-airstart launches.
1516 Delay. This value doesn't perform any checks, instead it
1517 inserts a delay between the time when the other
1518 parameters become true and when the pyro channel is
1524 Flight State. The flight software tracks the flight
1525 through a sequence of states:
1529 Boost. The motor has lit and the rocket is
1530 accelerating upwards.
1535 Fast. The motor has burned out and the rocket is
1536 descellerating, but it is going faster than 200m/s.
1541 Coast. The rocket is still moving upwards and
1542 decelerating, but the speed is less than 200m/s.
1547 Drogue. The rocket has reached apogee and is heading
1548 back down, but is above the configured Main
1554 Main. The rocket is still descending, and is below
1560 Landed. The rocket is no longer moving.
1566 You can select a state to limit when the pyro channel
1567 may activate; note that the check is based on when the
1568 rocket transitions <emphasis>into</emphasis> the state, and so checking for
1569 “greater than Boost” means that the rocket is currently
1570 in boost or some later state.
1573 When a motor burns out, the rocket enters either Fast or
1574 Coast state (depending on how fast it is moving). If the
1575 computer detects upwards acceleration again, it will
1576 move back to Boost state.
1585 <title>AltosUI</title>
1589 <imagedata fileref="altosui.png" width="4.6in"/>
1594 The AltosUI program provides a graphical user interface for
1595 interacting with the Altus Metrum product family. AltosUI can
1596 monitor telemetry data, configure devices and many other
1597 tasks. The primary interface window provides a selection of
1598 buttons, one for each major activity in the system. This chapter
1599 is split into sections, each of which documents one of the tasks
1600 provided from the top-level toolbar.
1603 <title>Monitor Flight</title>
1604 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
1606 Selecting this item brings up a dialog box listing all of the
1607 connected TeleDongle devices. When you choose one of these,
1608 AltosUI will create a window to display telemetry data as
1609 received by the selected TeleDongle device.
1614 <imagedata fileref="device-selection.png" width="3.1in"/>
1619 All telemetry data received are automatically recorded in
1620 suitable log files. The name of the files includes the current
1621 date and rocket serial and flight numbers.
1624 The radio frequency being monitored by the TeleDongle device is
1625 displayed at the top of the window. You can configure the
1626 frequency by clicking on the frequency box and selecting the desired
1627 frequency. AltosUI remembers the last frequency selected for each
1628 TeleDongle and selects that automatically the next time you use
1632 Below the TeleDongle frequency selector, the window contains a few
1633 significant pieces of information about the altimeter providing
1634 the telemetry data stream:
1638 <para>The configured call-sign</para>
1641 <para>The device serial number</para>
1644 <para>The flight number. Each altimeter remembers how many
1650 The rocket flight state. Each flight passes through several
1651 states including Pad, Boost, Fast, Coast, Drogue, Main and
1657 The Received Signal Strength Indicator value. This lets
1658 you know how strong a signal TeleDongle is receiving. The
1659 radio inside TeleDongle operates down to about -99dBm;
1660 weaker signals may not be receivable. The packet link uses
1661 error detection and correction techniques which prevent
1662 incorrect data from being reported.
1667 The age of the displayed data, in seconds since the last
1668 successfully received telemetry packet. In normal operation
1669 this will stay in the low single digits. If the number starts
1670 counting up, then you are no longer receiving data over the radio
1671 link from the flight computer.
1676 Finally, the largest portion of the window contains a set of
1677 tabs, each of which contain some information about the rocket.
1678 They're arranged in 'flight order' so that as the flight
1679 progresses, the selected tab automatically switches to display
1680 data relevant to the current state of the flight. You can select
1681 other tabs at any time. The final 'table' tab displays all of
1682 the raw telemetry values in one place in a spreadsheet-like format.
1685 <title>Launch Pad</title>
1689 <imagedata fileref="launch-pad.png" width="5.5in"/>
1694 The 'Launch Pad' tab shows information used to decide when the
1695 rocket is ready for flight. The first elements include red/green
1696 indicators, if any of these is red, you'll want to evaluate
1697 whether the rocket is ready to launch:
1700 <term>Battery Voltage</term>
1703 This indicates whether the Li-Po battery powering the
1704 flight computer has sufficient charge to last for
1705 the duration of the flight. A value of more than
1706 3.8V is required for a 'GO' status.
1711 <term>Apogee Igniter Voltage</term>
1714 This indicates whether the apogee
1715 igniter has continuity. If the igniter has a low
1716 resistance, then the voltage measured here will be close
1717 to the Li-Po battery voltage. A value greater than 3.2V is
1718 required for a 'GO' status.
1723 <term>Main Igniter Voltage</term>
1726 This indicates whether the main
1727 igniter has continuity. If the igniter has a low
1728 resistance, then the voltage measured here will be close
1729 to the Li-Po battery voltage. A value greater than 3.2V is
1730 required for a 'GO' status.
1735 <term>On-board Data Logging</term>
1738 This indicates whether there is
1739 space remaining on-board to store flight data for the
1740 upcoming flight. If you've downloaded data, but failed
1741 to erase flights, there may not be any space
1742 left. Most of our flight computers can store multiple
1743 flights, depending on the configured maximum flight log
1744 size. TeleMini v1.0 stores only a single flight, so it
1746 downloaded and erased after each flight to capture
1747 data. This only affects on-board flight logging; the
1748 altimeter will still transmit telemetry and fire
1749 ejection charges at the proper times even if the flight
1750 data storage is full.
1755 <term>GPS Locked</term>
1758 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
1759 currently able to compute position information. GPS requires
1760 at least 4 satellites to compute an accurate position.
1765 <term>GPS Ready</term>
1768 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
1769 10 consecutive positions without losing lock. This ensures
1770 that the GPS receiver has reliable reception from the
1778 The Launchpad tab also shows the computed launch pad position
1779 and altitude, averaging many reported positions to improve the
1780 accuracy of the fix.
1784 <title>Ascent</title>
1788 <imagedata fileref="ascent.png" width="5.5in"/>
1793 This tab is shown during Boost, Fast and Coast
1794 phases. The information displayed here helps monitor the
1795 rocket as it heads towards apogee.
1798 The height, speed, acceleration and tilt are shown along
1799 with the maximum values for each of them. This allows you to
1800 quickly answer the most commonly asked questions you'll hear
1804 The current latitude and longitude reported by the GPS are
1805 also shown. Note that under high acceleration, these values
1806 may not get updated as the GPS receiver loses position
1807 fix. Once the rocket starts coasting, the receiver should
1808 start reporting position again.
1811 Finally, the current igniter voltages are reported as in the
1812 Launch Pad tab. This can help diagnose deployment failures
1813 caused by wiring which comes loose under high acceleration.
1817 <title>Descent</title>
1821 <imagedata fileref="descent.png" width="5.5in"/>
1826 Once the rocket has reached apogee and (we hope) activated the
1827 apogee charge, attention switches to tracking the rocket on
1828 the way back to the ground, and for dual-deploy flights,
1829 waiting for the main charge to fire.
1832 To monitor whether the apogee charge operated correctly, the
1833 current descent rate is reported along with the current
1834 height. Good descent rates vary based on the choice of recovery
1835 components, but generally range from 15-30m/s on drogue and should
1836 be below 10m/s when under the main parachute in a dual-deploy flight.
1839 With GPS-equipped flight computers, you can locate the rocket in the
1840 sky using the elevation and bearing information to figure
1841 out where to look. Elevation is in degrees above the
1842 horizon. Bearing is reported in degrees relative to true
1843 north. Range can help figure out how big the rocket will
1844 appear. Ground Distance shows how far it is to a point
1845 directly under the rocket and can help figure out where the
1846 rocket is likely to land. Note that all of these values are
1847 relative to the pad location. If the elevation is near 90°,
1848 the rocket is over the pad, not over you.
1851 Finally, the igniter voltages are reported in this tab as
1852 well, both to monitor the main charge as well as to see what
1853 the status of the apogee charge is. Note that some commercial
1854 e-matches are designed to retain continuity even after being
1855 fired, and will continue to show as green or return from red to
1860 <title>Landed</title>
1864 <imagedata fileref="landed.png" width="5.5in"/>
1869 Once the rocket is on the ground, attention switches to
1870 recovery. While the radio signal is often lost once the
1871 rocket is on the ground, the last reported GPS position is
1872 generally within a short distance of the actual landing location.
1875 The last reported GPS position is reported both by
1876 latitude and longitude as well as a bearing and distance from
1877 the launch pad. The distance should give you a good idea of
1878 whether to walk or hitch a ride. Take the reported
1879 latitude and longitude and enter them into your hand-held GPS
1880 unit and have that compute a track to the landing location.
1883 Our flight computers will continue to transmit RDF
1884 tones after landing, allowing you to locate the rocket by
1885 following the radio signal if necessary. You may need to get
1886 away from the clutter of the flight line, or even get up on
1887 a hill (or your neighbor's RV roof) to receive the RDF signal.
1890 The maximum height, speed and acceleration reported
1891 during the flight are displayed for your admiring observers.
1892 The accuracy of these immediate values depends on the quality
1893 of your radio link and how many packets were received.
1894 Recovering the on-board data after flight may yield
1895 more precise results.
1898 To get more detailed information about the flight, you can
1899 click on the 'Graph Flight' button which will bring up a
1900 graph window for the current flight.
1904 <title>Table</title>
1908 <imagedata fileref="table.png" width="5.5in"/>
1913 The table view shows all of the data available from the
1914 flight computer. Probably the most useful data on
1915 this tab is the detailed GPS information, which includes
1916 horizontal dilution of precision information, and
1917 information about the signal being received from the satellites.
1921 <title>Site Map</title>
1925 <imagedata fileref="site-map.png" width="5.5in"/>
1930 When the TeleMetrum has a GPS fix, the Site Map tab will map
1931 the rocket's position to make it easier for you to locate the
1932 rocket, both while it is in the air, and when it has landed. The
1933 rocket's state is indicated by color: white for pad, red for
1934 boost, pink for fast, yellow for coast, light blue for drogue,
1935 dark blue for main, and black for landed.
1938 The map's scale is approximately 3m (10ft) per pixel. The map
1939 can be dragged using the left mouse button. The map will attempt
1940 to keep the rocket roughly centered while data is being received.
1943 Images are fetched automatically via the Google Maps Static API,
1944 and cached on disk for reuse. If map images cannot be downloaded,
1945 the rocket's path will be traced on a dark gray background
1949 You can pre-load images for your favorite launch sites
1950 before you leave home; check out the 'Preload Maps' section below.
1955 <title>Save Flight Data</title>
1957 The altimeter records flight data to its internal flash memory.
1958 TeleMetrum data is recorded at a much higher rate than the telemetry
1959 system can handle, and is not subject to radio drop-outs. As
1960 such, it provides a more complete and precise record of the
1961 flight. The 'Save Flight Data' button allows you to read the
1962 flash memory and write it to disk.
1965 Clicking on the 'Save Flight Data' button brings up a list of
1966 connected flight computers and TeleDongle devices. If you select a
1967 flight computer, the flight data will be downloaded from that
1968 device directly. If you select a TeleDongle device, flight data
1969 will be downloaded from a flight computer over radio link via the
1970 specified TeleDongle. See the chapter on Controlling An Altimeter
1971 Over The Radio Link for more information.
1974 After the device has been selected, a dialog showing the
1975 flight data saved in the device will be shown allowing you to
1976 select which flights to download and which to delete. With
1977 version 0.9 or newer firmware, you must erase flights in order
1978 for the space they consume to be reused by another
1979 flight. This prevents accidentally losing flight data
1980 if you neglect to download data before flying again. Note that
1981 if there is no more space available in the device, then no
1982 data will be recorded during the next flight.
1985 The file name for each flight log is computed automatically
1986 from the recorded flight date, altimeter serial number and
1987 flight number information.
1991 <title>Replay Flight</title>
1993 Select this button and you are prompted to select a flight
1994 record file, either a .telem file recording telemetry data or a
1995 .eeprom file containing flight data saved from the altimeter
1999 Once a flight record is selected, the flight monitor interface
2000 is displayed and the flight is re-enacted in real time. Check
2001 the Monitor Flight chapter above to learn how this window operates.
2005 <title>Graph Data</title>
2007 Select this button and you are prompted to select a flight
2008 record file, either a .telem file recording telemetry data or a
2009 .eeprom file containing flight data saved from
2013 Note that telemetry files will generally produce poor graphs
2014 due to the lower sampling rate and missed telemetry packets.
2015 Use saved flight data in .eeprom files for graphing where possible.
2018 Once a flight record is selected, a window with multiple tabs is
2022 <title>Flight Graph</title>
2026 <imagedata fileref="graph.png" width="6in" scalefit="1"/>
2031 By default, the graph contains acceleration (blue),
2032 velocity (green) and altitude (red).
2035 The graph can be zoomed into a particular area by clicking and
2036 dragging down and to the right. Once zoomed, the graph can be
2037 reset by clicking and dragging up and to the left. Holding down
2038 control and clicking and dragging allows the graph to be panned.
2039 The right mouse button causes a pop-up menu to be displayed, giving
2040 you the option save or print the plot.
2044 <title>Configure Graph</title>
2048 <imagedata fileref="graph-configure.png" width="6in" scalefit="1"/>
2053 This selects which graph elements to show, and, at the
2054 very bottom, lets you switch between metric and
2059 <title>Flight Statistics</title>
2063 <imagedata fileref="graph-stats.png" width="6in" scalefit="1"/>
2068 Shows overall data computed from the flight.
2076 <imagedata fileref="graph-map.png" width="6in" scalefit="1"/>
2081 Shows a satellite image of the flight area overlaid
2082 with the path of the flight. The red concentric
2083 circles mark the launch pad, the black concentric
2084 circles mark the landing location.
2089 <title>Export Data</title>
2091 This tool takes the raw data files and makes them available for
2092 external analysis. When you select this button, you are prompted to
2093 select a flight data file, which can be either a .eeprom or .telem.
2094 The .eeprom files contain higher resolution and more continuous data,
2095 while .telem files contain receiver signal strength information.
2096 Next, a second dialog appears which is used to select
2097 where to write the resulting file. It has a selector to choose
2098 between CSV and KML file formats.
2101 <title>Comma Separated Value Format</title>
2103 This is a text file containing the data in a form suitable for
2104 import into a spreadsheet or other external data analysis
2105 tool. The first few lines of the file contain the version and
2106 configuration information from the altimeter, then
2107 there is a single header line which labels all of the
2108 fields. All of these lines start with a '#' character which
2109 many tools can be configured to skip over.
2112 The remaining lines of the file contain the data, with each
2113 field separated by a comma and at least one space. All of
2114 the sensor values are converted to standard units, with the
2115 barometric data reported in both pressure, altitude and
2116 height above pad units.
2120 <title>Keyhole Markup Language (for Google Earth)</title>
2122 This is the format used by Google Earth to provide an overlay
2123 within that application. With this, you can use Google Earth to
2124 see the whole flight path in 3D.
2129 <title>Configure Altimeter</title>
2133 <imagedata fileref="configure-altimeter.png" width="3.6in" scalefit="1"/>
2138 Select this button and then select either an altimeter or
2139 TeleDongle Device from the list provided. Selecting a TeleDongle
2140 device will use the radio link to configure a remote altimeter.
2143 The first few lines of the dialog provide information about the
2144 connected device, including the product name,
2145 software version and hardware serial number. Below that are the
2146 individual configuration entries.
2149 At the bottom of the dialog, there are four buttons:
2156 This writes any changes to the
2157 configuration parameter block in flash memory. If you don't
2158 press this button, any changes you make will be lost.
2166 This resets the dialog to the most recently saved values,
2167 erasing any changes you have made.
2175 This reboots the device. Use this to
2176 switch from idle to pad mode by rebooting once the rocket is
2177 oriented for flight, or to confirm changes you think you saved
2186 This closes the dialog. Any unsaved changes will be
2193 The rest of the dialog contains the parameters to be configured.
2196 <title>Main Deploy Altitude</title>
2198 This sets the altitude (above the recorded pad altitude) at
2199 which the 'main' igniter will fire. The drop-down menu shows
2200 some common values, but you can edit the text directly and
2201 choose whatever you like. If the apogee charge fires below
2202 this altitude, then the main charge will fire two seconds
2203 after the apogee charge fires.
2207 <title>Apogee Delay</title>
2209 When flying redundant electronics, it's often important to
2210 ensure that multiple apogee charges don't fire at precisely
2211 the same time, as that can over pressurize the apogee deployment
2212 bay and cause a structural failure of the air-frame. The Apogee
2213 Delay parameter tells the flight computer to fire the apogee
2214 charge a certain number of seconds after apogee has been
2219 <title>Radio Frequency</title>
2221 This configures which of the frequencies to use for both
2222 telemetry and packet command mode. Note that if you set this
2223 value via packet command mode, the TeleDongle frequency will
2224 also be automatically reconfigured to match so that
2225 communication will continue afterwards.
2229 <title>RF Calibration</title>
2231 The radios in every Altus Metrum device are calibrated at the
2232 factory to ensure that they transmit and receive on the
2233 specified frequency. If you need to you can adjust the calibration
2234 by changing this value. Do not do this without understanding what
2235 the value means, read the appendix on calibration and/or the source
2236 code for more information. To change a TeleDongle's calibration,
2237 you must reprogram the unit completely.
2241 <title>Telemetry/RDF/APRS Enable</title>
2243 Enables the radio for transmission during flight. When
2244 disabled, the radio will not transmit anything during flight
2249 <title>APRS Interval</title>
2251 How often to transmit GPS information via APRS. This option
2252 is available on TeleMetrum v2 and TeleMega
2253 boards. TeleMetrum v1 boards cannot transmit APRS
2254 packets. Note that a single APRS packet takes nearly a full
2255 second to transmit, so enabling this option will prevent
2256 sending any other telemetry during that time.
2260 <title>Callsign</title>
2262 This sets the call sign included in each telemetry packet. Set this
2263 as needed to conform to your local radio regulations.
2267 <title>Maximum Flight Log Size</title>
2269 This sets the space (in kilobytes) allocated for each flight
2270 log. The available space will be divided into chunks of this
2271 size. A smaller value will allow more flights to be stored,
2272 a larger value will record data from longer flights.
2276 <title>Ignite Mode</title>
2278 TeleMetrum and TeleMini provide two igniter channels as they
2279 were originally designed as dual-deploy flight
2280 computers. This configuration parameter allows the two
2281 channels to be used in different configurations.
2285 <term>Dual Deploy</term>
2288 This is the usual mode of operation; the
2289 'apogee' channel is fired at apogee and the 'main'
2290 channel at the height above ground specified by the
2291 'Main Deploy Altitude' during descent.
2296 <term>Redundant Apogee</term>
2299 This fires both channels at
2300 apogee, the 'apogee' channel first followed after a two second
2301 delay by the 'main' channel.
2306 <term>Redundant Main</term>
2309 This fires both channels at the
2310 height above ground specified by the Main Deploy
2311 Altitude setting during descent. The 'apogee'
2312 channel is fired first, followed after a two second
2313 delay by the 'main' channel.
2320 <title>Pad Orientation</title>
2322 Because they include accelerometers, TeleMetrum and
2323 TeleMega are sensitive to the orientation of the board. By
2324 default, they expect the antenna end to point forward. This
2325 parameter allows that default to be changed, permitting the
2326 board to be mounted with the antenna pointing aft instead.
2330 <term>Antenna Up</term>
2333 In this mode, the antenna end of the
2334 flight computer must point forward, in line with the
2335 expected flight path.
2340 <term>Antenna Down</term>
2343 In this mode, the antenna end of the
2344 flight computer must point aft, in line with the
2345 expected flight path.
2352 <title>Configure Pyro Channels</title>
2356 <imagedata fileref="configure-pyro.png" width="6in" scalefit="1"/>
2361 This opens a separate window to configure the additional
2362 pyro channels available on TeleMega. One column is
2363 presented for each channel. Each row represents a single
2364 parameter, if enabled the parameter must meet the specified
2365 test for the pyro channel to be fired. See the Pyro Channels
2366 section in the System Operation chapter above for a
2367 description of these parameters.
2370 Select conditions and set the related value; the pyro
2371 channel will be activated when <emphasis>all</emphasis> of the
2372 conditions are met. Each pyro channel has a separate set of
2373 configuration values, so you can use different values for
2374 the same condition with different channels.
2377 Once you have selected the appropriate configuration for all
2378 of the necessary pyro channels, you can save the pyro
2379 configuration along with the rest of the flight computer
2380 configuration by pressing the 'Save' button in the main
2381 Configure Flight Computer window.
2386 <title>Configure AltosUI</title>
2390 <imagedata fileref="configure-altosui.png" width="2.4in" scalefit="1"/>
2395 This button presents a dialog so that you can configure the AltosUI global settings.
2398 <title>Voice Settings</title>
2400 AltosUI provides voice announcements during flight so that you
2401 can keep your eyes on the sky and still get information about
2402 the current flight status. However, sometimes you don't want
2409 <para>Turns all voice announcements on and off</para>
2413 <term>Test Voice</term>
2416 Plays a short message allowing you to verify
2417 that the audio system is working and the volume settings
2425 <title>Log Directory</title>
2427 AltosUI logs all telemetry data and saves all TeleMetrum flash
2428 data to this directory. This directory is also used as the
2429 staring point when selecting data files for display or export.
2432 Click on the directory name to bring up a directory choosing
2433 dialog, select a new directory and click 'Select Directory' to
2434 change where AltosUI reads and writes data files.
2438 <title>Callsign</title>
2440 This value is transmitted in each command packet sent from
2441 TeleDongle and received from an altimeter. It is not used in
2442 telemetry mode, as the callsign configured in the altimeter board
2443 is included in all telemetry packets. Configure this
2444 with the AltosUI operators call sign as needed to comply with
2445 your local radio regulations.
2448 Note that to successfully command a flight computer over the radio
2449 (to configure the altimeter, monitor idle, or fire pyro charges),
2450 the callsign configured here must exactly match the callsign
2451 configured in the flight computer. This matching is case
2456 <title>Imperial Units</title>
2458 This switches between metric units (meters) and imperial
2459 units (feet and miles). This affects the display of values
2460 use during flight monitoring, configuration, data graphing
2461 and all of the voice announcements. It does not change the
2462 units used when exporting to CSV files, those are always
2463 produced in metric units.
2467 <title>Font Size</title>
2469 Selects the set of fonts used in the flight monitor
2470 window. Choose between the small, medium and large sets.
2474 <title>Serial Debug</title>
2476 This causes all communication with a connected device to be
2477 dumped to the console from which AltosUI was started. If
2478 you've started it from an icon or menu entry, the output
2479 will simply be discarded. This mode can be useful to debug
2480 various serial communication issues.
2484 <title>Manage Frequencies</title>
2486 This brings up a dialog where you can configure the set of
2487 frequencies shown in the various frequency menus. You can
2488 add as many as you like, or even reconfigure the default
2489 set. Changing this list does not affect the frequency
2490 settings of any devices, it only changes the set of
2491 frequencies shown in the menus.
2496 <title>Configure Groundstation</title>
2500 <imagedata fileref="configure-groundstation.png" width="3.1in" scalefit="1"/>
2505 Select this button and then select a TeleDongle Device from the list provided.
2508 The first few lines of the dialog provide information about the
2509 connected device, including the product name,
2510 software version and hardware serial number. Below that are the
2511 individual configuration entries.
2514 Note that the TeleDongle itself doesn't save any configuration
2515 data, the settings here are recorded on the local machine in
2516 the Java preferences database. Moving the TeleDongle to
2517 another machine, or using a different user account on the same
2518 machine will cause settings made here to have no effect.
2521 At the bottom of the dialog, there are three buttons:
2528 This writes any changes to the
2529 local Java preferences file. If you don't
2530 press this button, any changes you make will be lost.
2538 This resets the dialog to the most recently saved values,
2539 erasing any changes you have made.
2547 This closes the dialog. Any unsaved changes will be
2554 The rest of the dialog contains the parameters to be configured.
2557 <title>Frequency</title>
2559 This configures the frequency to use for both telemetry and
2560 packet command mode. Set this before starting any operation
2561 involving packet command mode so that it will use the right
2562 frequency. Telemetry monitoring mode also provides a menu to
2563 change the frequency, and that menu also sets the same Java
2564 preference value used here.
2568 <title>Radio Calibration</title>
2570 The radios in every Altus Metrum device are calibrated at the
2571 factory to ensure that they transmit and receive on the
2572 specified frequency. To change a TeleDongle's calibration,
2573 you must reprogram the unit completely, so this entry simply
2574 shows the current value and doesn't allow any changes.
2579 <title>Flash Image</title>
2581 This reprograms Altus Metrum devices with new
2582 firmware. TeleMetrum v1.x, TeleDongle, TeleMini and TeleBT are
2583 all reprogrammed by using another similar unit as a
2584 programming dongle (pair programming). TeleMega, TeleMetrum v2
2585 and EasyMini are all programmed directly over their USB ports
2586 (self programming). Please read the directions for flashing
2587 devices in the Updating Device Firmware chapter below.
2591 <title>Fire Igniter</title>
2595 <imagedata fileref="fire-igniter.png" width="1.2in" scalefit="1"/>
2600 This activates the igniter circuits in the flight computer to help
2601 test recovery systems deployment. Because this command can operate
2602 over the Packet Command Link, you can prepare the rocket as
2603 for flight and then test the recovery system without needing
2604 to snake wires inside the air-frame.
2607 Selecting the 'Fire Igniter' button brings up the usual device
2608 selection dialog. Pick the desired device. This brings up another
2609 window which shows the current continuity test status for all
2610 of the pyro channels.
2613 Next, select the desired igniter to fire. This will enable the
2617 Select the 'Arm' button. This enables the 'Fire' button. The
2618 word 'Arm' is replaced by a countdown timer indicating that
2619 you have 10 seconds to press the 'Fire' button or the system
2620 will deactivate, at which point you start over again at
2621 selecting the desired igniter.
2625 <title>Scan Channels</title>
2629 <imagedata fileref="scan-channels.png" width="3.2in" scalefit="1"/>
2634 This listens for telemetry packets on all of the configured
2635 frequencies, displaying information about each device it
2636 receives a packet from. You can select which of the three
2637 telemetry formats should be tried; by default, it only listens
2638 for the standard telemetry packets used in v1.0 and later
2643 <title>Load Maps</title>
2647 <imagedata fileref="load-maps.png" width="5.2in" scalefit="1"/>
2652 Before heading out to a new launch site, you can use this to
2653 load satellite images in case you don't have internet
2654 connectivity at the site. This loads a fairly large area
2655 around the launch site, which should cover any flight you're likely to make.
2658 There's a drop-down menu of launch sites we know about; if
2659 your favorites aren't there, please let us know the lat/lon
2660 and name of the site. The contents of this list are actually
2661 downloaded from our server at run-time, so as new sites are sent
2662 in, they'll get automatically added to this list.
2665 If the launch site isn't in the list, you can manually enter the lat/lon values
2668 Clicking the 'Load Map' button will fetch images from Google
2669 Maps; note that Google limits how many images you can fetch at
2670 once, so if you load more than one launch site, you may get
2671 some gray areas in the map which indicate that Google is tired
2672 of sending data to you. Try again later.
2676 <title>Monitor Idle</title>
2678 This brings up a dialog similar to the Monitor Flight UI,
2679 except it works with the altimeter in “idle” mode by sending
2680 query commands to discover the current state rather than
2681 listening for telemetry packets. Because this uses command
2682 mode, it needs to have the TeleDongle and flight computer
2683 callsigns match exactly. If you can receive telemetry, but
2684 cannot manage to run Monitor Idle, then it's very likely that
2685 your callsigns are different in some way.
2690 <title>AltosDroid</title>
2692 AltosDroid provides the same flight monitoring capabilities as
2693 AltosUI, but runs on Android devices and is designed to connect
2694 to a TeleBT receiver over Bluetooth™. AltosDroid monitors
2695 telemetry data, logging it to internal storage in the Android
2696 device, and presents that data in a UI the same way the 'Monitor
2697 Flight' window does in AltosUI.
2700 This manual will explain how to configure AltosDroid, connect
2701 to TeleBT, operate the flight monitoring interface and describe
2702 what the displayed data means.
2705 <title>Installing AltosDroid</title>
2707 AltosDroid is available from the Google Play store. To install
2708 it on your Android device, open the Google Play Store
2709 application and search for “altosdroid”. Make sure you don't
2710 have a space between “altos” and “droid” or you probably won't
2711 find what you want. That should bring you to the right page
2712 from which you can download and install the application.
2716 <title>Connecting to TeleBT</title>
2718 Press the Android 'Menu' button or soft-key to see the
2719 configuration options available. Select the 'Connect a device'
2720 option and then the 'Scan for devices' entry at the bottom to
2721 look for your TeleBT device. Select your device, and when it
2722 asks for the code, enter '1234'.
2725 Subsequent connections will not require you to enter that
2726 code, and your 'paired' device will appear in the list without
2731 <title>Configuring AltosDroid</title>
2733 The only configuration option available for AltosDroid is
2734 which frequency to listen on. Press the Android 'Menu' button
2735 or soft-key and pick the 'Select radio frequency' entry. That
2736 brings up a menu of pre-set radio frequencies; pick the one
2737 which matches your altimeter.
2741 <title>AltosDroid Flight Monitoring</title>
2743 AltosDroid is designed to mimic the AltosUI flight monitoring
2744 display, providing separate tabs for each stage of your rocket
2745 flight along with a tab containing a map of the local area
2746 with icons marking the current location of the altimeter and
2752 The 'Launch Pad' tab shows information used to decide when the
2753 rocket is ready for flight. The first elements include red/green
2754 indicators, if any of these is red, you'll want to evaluate
2755 whether the rocket is ready to launch:
2758 <term>Battery Voltage</term>
2761 This indicates whether the Li-Po battery
2762 powering the TeleMetrum has sufficient charge to last for
2763 the duration of the flight. A value of more than
2764 3.8V is required for a 'GO' status.
2769 <term>Apogee Igniter Voltage</term>
2772 This indicates whether the apogee
2773 igniter has continuity. If the igniter has a low
2774 resistance, then the voltage measured here will be close
2775 to the Li-Po battery voltage. A value greater than 3.2V is
2776 required for a 'GO' status.
2781 <term>Main Igniter Voltage</term>
2784 This indicates whether the main
2785 igniter has continuity. If the igniter has a low
2786 resistance, then the voltage measured here will be close
2787 to the Li-Po battery voltage. A value greater than 3.2V is
2788 required for a 'GO' status.
2793 <term>On-board Data Logging</term>
2796 This indicates whether there is
2797 space remaining on-board to store flight data for the
2798 upcoming flight. If you've downloaded data, but failed
2799 to erase flights, there may not be any space
2800 left. TeleMetrum can store multiple flights, depending
2801 on the configured maximum flight log size. TeleMini
2802 stores only a single flight, so it will need to be
2803 downloaded and erased after each flight to capture
2804 data. This only affects on-board flight logging; the
2805 altimeter will still transmit telemetry and fire
2806 ejection charges at the proper times.
2811 <term>GPS Locked</term>
2814 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
2815 currently able to compute position information. GPS requires
2816 at least 4 satellites to compute an accurate position.
2821 <term>GPS Ready</term>
2824 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
2825 10 consecutive positions without losing lock. This ensures
2826 that the GPS receiver has reliable reception from the
2834 The Launchpad tab also shows the computed launch pad position
2835 and altitude, averaging many reported positions to improve the
2836 accuracy of the fix.
2841 <title>Downloading Flight Logs</title>
2843 AltosDroid always saves every bit of telemetry data it
2844 receives. To download that to a computer for use with AltosUI,
2845 simply remove the SD card from your Android device, or connect
2846 your device to your computer's USB port and browse the files
2847 on that device. You will find '.telem' files in the TeleMetrum
2848 directory that will work with AltosUI directly.
2853 <title>Using Altus Metrum Products</title>
2855 <title>Being Legal</title>
2857 First off, in the US, you need an <ulink url="http://www.altusmetrum.org/Radio/">amateur radio license</ulink> or
2858 other authorization to legally operate the radio transmitters that are part
2863 <title>In the Rocket</title>
2865 In the rocket itself, you just need a flight computer and
2866 a single-cell, 3.7 volt nominal Li-Po rechargeable battery. An
2867 850mAh battery weighs less than a 9V alkaline battery, and will
2868 run a TeleMetrum or TeleMega for hours.
2869 A 110mAh battery weighs less than a triple A battery and is a good
2870 choice for use with TeleMini.
2873 By default, we ship flight computers with a simple wire antenna.
2874 If your electronics bay or the air-frame it resides within is made
2875 of carbon fiber, which is opaque to RF signals, you may prefer to
2876 install an SMA connector so that you can run a coaxial cable to an
2877 antenna mounted elsewhere in the rocket. However, note that the
2878 GPS antenna is fixed on all current products, so you really want
2879 to install the flight computer in a bay made of RF-transparent
2880 materials if at all possible.
2884 <title>On the Ground</title>
2886 To receive the data stream from the rocket, you need an antenna and short
2887 feed-line connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. If possible, use an SMA to BNC
2888 adapter instead of feedline between the antenna feedpoint and
2889 TeleDongle, as this will give you the best performance. The
2890 TeleDongle in turn plugs directly into the USB port on a notebook
2891 computer. Because TeleDongle looks like a simple serial port, your computer
2892 does not require special device drivers... just plug it in.
2895 The GUI tool, AltosUI, is written in Java and runs across
2896 Linux, Mac OS and Windows. There's also a suite of C tools
2897 for Linux which can perform most of the same tasks.
2900 Alternatively, a TeleBT attached with an SMA to BNC adapter at the
2901 feed point of a hand-held yagi used in conjunction with an Android
2902 device running AltosDroid makes an outstanding ground station.
2905 After the flight, you can use the radio link to extract the more detailed data
2906 logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
2907 TeleMetrum board directly. Pulling out the data without having to open up
2908 the rocket is pretty cool! A USB cable is also how you charge the Li-Po
2909 battery, so you'll want one of those anyway... the same cable used by lots
2910 of digital cameras and other modern electronic stuff will work fine.
2913 If your rocket lands out of sight, you may enjoy having a hand-held
2914 GPS receiver, so that you can put in a way-point for the last
2915 reported rocket position before touch-down. This makes looking for
2916 your rocket a lot like Geo-Caching... just go to the way-point and
2917 look around starting from there. AltosDroid on an Android device
2918 with GPS receiver works great for this, too!
2921 You may also enjoy having a ham radio “HT” that covers the 70cm band... you
2922 can use that with your antenna to direction-find the rocket on the ground
2923 the same way you can use a Walston or Beeline tracker. This can be handy
2924 if the rocket is hiding in sage brush or a tree, or if the last GPS position
2925 doesn't get you close enough because the rocket dropped into a canyon, or
2926 the wind is blowing it across a dry lake bed, or something like that... Keith
2927 currently uses a Yaesu VX-7R, Bdale has a Baofung UV-5R
2928 which isn't as nice, but was a whole lot cheaper.
2931 So, to recap, on the ground the hardware you'll need includes:
2932 <orderedlist inheritnum='inherit' numeration='arabic'>
2935 an antenna and feed-line or adapter
2950 optionally, a hand-held GPS receiver
2955 optionally, an HT or receiver covering 435 MHz
2961 The best hand-held commercial directional antennas we've found for radio
2962 direction finding rockets are from
2963 <ulink url="http://www.arrowantennas.com/" >
2966 The 440-3 and 440-5 are both good choices for finding a
2967 TeleMetrum- or TeleMini- equipped rocket when used with a suitable
2968 70cm HT. TeleDongle and an SMA to BNC adapter fit perfectly
2969 between the driven element and reflector of Arrow antennas.
2973 <title>Data Analysis</title>
2975 Our software makes it easy to log the data from each flight, both the
2976 telemetry received during the flight itself, and the more
2977 complete data log recorded in the flash memory on the altimeter
2978 board. Once this data is on your computer, our post-flight tools make it
2979 easy to quickly get to the numbers everyone wants, like apogee altitude,
2980 max acceleration, and max velocity. You can also generate and view a
2981 standard set of plots showing the altitude, acceleration, and
2982 velocity of the rocket during flight. And you can even export a TeleMetrum data file
2983 usable with Google Maps and Google Earth for visualizing the flight path
2984 in two or three dimensions!
2987 Our ultimate goal is to emit a set of files for each flight that can be
2988 published as a web page per flight, or just viewed on your local disk with
2993 <title>Future Plans</title>
2995 We've designed a simple GPS based radio tracker called TeleGPS.
2996 If all goes well, we hope to introduce this in the first
3000 We have designed and prototyped several “companion boards” that
3001 can attach to the companion connector on TeleMetrum and TeleMega
3002 flight computers to collect more data, provide more pyro channels,
3003 and so forth. We do not yet know if or when any of these boards
3004 will be produced in enough quantity to sell. If you have specific
3005 interests for data collection or control of events in your rockets
3006 beyond the capabilities of our existing productions, please let
3010 Because all of our work is open, both the hardware designs and the
3011 software, if you have some great idea for an addition to the current
3012 Altus Metrum family, feel free to dive in and help! Or let us know
3013 what you'd like to see that we aren't already working on, and maybe
3014 we'll get excited about it too...
3018 <ulink url="http://altusmetrum.org/">web site</ulink> for more news
3019 and information as our family of products evolves!
3024 <title>Altimeter Installation Recommendations</title>
3026 Building high-power rockets that fly safely is hard enough. Mix
3027 in some sophisticated electronics and a bunch of radio energy
3028 and some creativity and/or compromise may be required. This chapter
3029 contains some suggestions about how to install Altus Metrum
3030 products into a rocket air-frame, including how to safely and
3031 reliably mix a variety of electronics into the same air-frame.
3034 <title>Mounting the Altimeter</title>
3036 The first consideration is to ensure that the altimeter is
3037 securely fastened to the air-frame. For most of our products, we
3038 prefer nylon standoffs and nylon screws; they're good to at least 50G
3039 and cannot cause any electrical issues on the board. Metal screws
3040 and standoffs are fine, too, just be careful to avoid electrical
3041 shorts! For TeleMini v1.0, we usually cut small pieces of 1/16 inch
3043 under the screw holes, and then take 2x56 nylon screws and
3044 screw them through the TeleMini mounting holes, through the
3045 balsa and into the underlying material.
3047 <orderedlist inheritnum='inherit' numeration='arabic'>
3050 Make sure accelerometer-equipped products like TeleMetrum and
3051 TeleMega are aligned precisely along the axis of
3052 acceleration so that the accelerometer can accurately
3053 capture data during the flight.
3058 Watch for any metal touching components on the
3059 board. Shorting out connections on the bottom of the board
3060 can cause the altimeter to fail during flight.
3066 <title>Dealing with the Antenna</title>
3068 The antenna supplied is just a piece of solid, insulated,
3069 wire. If it gets damaged or broken, it can be easily
3070 replaced. It should be kept straight and not cut; bending or
3071 cutting it will change the resonant frequency and/or
3072 impedance, making it a less efficient radiator and thus
3073 reducing the range of the telemetry signal.
3076 Keeping metal away from the antenna will provide better range
3077 and a more even radiation pattern. In most rockets, it's not
3078 entirely possible to isolate the antenna from metal
3079 components; there are often bolts, all-thread and wires from other
3080 electronics to contend with. Just be aware that the more stuff
3081 like this around the antenna, the lower the range.
3084 Make sure the antenna is not inside a tube made or covered
3085 with conducting material. Carbon fiber is the most common
3086 culprit here -- CF is a good conductor and will effectively
3087 shield the antenna, dramatically reducing signal strength and
3088 range. Metallic flake paint is another effective shielding
3089 material which should be avoided around any antennas.
3092 If the ebay is large enough, it can be convenient to simply
3093 mount the altimeter at one end and stretch the antenna out
3094 inside. Taping the antenna to the sled can keep it straight
3095 under acceleration. If there are metal rods, keep the
3096 antenna as far away as possible.
3099 For a shorter ebay, it's quite practical to have the antenna
3100 run through a bulkhead and into an adjacent bay. Drill a small
3101 hole in the bulkhead, pass the antenna wire through it and
3102 then seal it up with glue or clay. We've also used acrylic
3103 tubing to create a cavity for the antenna wire. This works a
3104 bit better in that the antenna is known to stay straight and
3105 not get folded by recovery components in the bay. Angle the
3106 tubing towards the side wall of the rocket and it ends up
3107 consuming very little space.
3110 If you need to place the UHF antenna at a distance from the
3111 altimeter, you can replace the antenna with an edge-mounted
3112 SMA connector, and then run 50Ω coax from the board to the
3113 antenna. Building a remote antenna is beyond the scope of this
3118 <title>Preserving GPS Reception</title>
3120 The GPS antenna and receiver used in TeleMetrum and TeleMega is
3121 highly sensitive and normally have no trouble tracking enough
3122 satellites to provide accurate position information for
3123 recovering the rocket. However, there are many ways the GPS signal
3124 can end up attenuated, negatively affecting GPS performance.
3125 <orderedlist inheritnum='inherit' numeration='arabic'>
3128 Conductive tubing or coatings. Carbon fiber and metal
3129 tubing, or metallic paint will all dramatically attenuate the
3130 GPS signal. We've never heard of anyone successfully
3131 receiving GPS from inside these materials.
3136 Metal components near the GPS patch antenna. These will
3137 de-tune the patch antenna, changing the resonant frequency
3138 away from the L1 carrier and reduce the effectiveness of the
3139 antenna. You can place as much stuff as you like beneath the
3140 antenna as that's covered with a ground plane. But, keep
3141 wires and metal out from above the patch antenna.
3148 <title>Radio Frequency Interference</title>
3150 Any altimeter will generate RFI; the digital circuits use
3151 high-frequency clocks that spray radio interference across a
3152 wide band. Altus Metrum altimeters generate intentional radio
3153 signals as well, increasing the amount of RF energy around the board.
3156 Rocketry altimeters also use precise sensors measuring air
3157 pressure and acceleration. Tiny changes in voltage can cause
3158 these sensor readings to vary by a huge amount. When the
3159 sensors start mis-reporting data, the altimeter can either
3160 fire the igniters at the wrong time, or not fire them at all.
3163 Voltages are induced when radio frequency energy is
3164 transmitted from one circuit to another. Here are things that
3165 influence the induced voltage and current:
3170 Keep wires from different circuits apart. Moving circuits
3171 further apart will reduce RFI.
3176 Avoid parallel wires from different circuits. The longer two
3177 wires run parallel to one another, the larger the amount of
3178 transferred energy. Cross wires at right angles to reduce
3184 Twist wires from the same circuits. Two wires the same
3185 distance from the transmitter will get the same amount of
3186 induced energy which will then cancel out. Any time you have
3187 a wire pair running together, twist the pair together to
3188 even out distances and reduce RFI. For altimeters, this
3189 includes battery leads, switch hookups and igniter
3195 Avoid resonant lengths. Know what frequencies are present
3196 in the environment and avoid having wire lengths near a
3197 natural resonant length. Altus Metrum products transmit on the
3198 70cm amateur band, so you should avoid lengths that are a
3199 simple ratio of that length; essentially any multiple of ¼
3200 of the wavelength (17.5cm).
3206 <title>The Barometric Sensor</title>
3208 Altusmetrum altimeters measure altitude with a barometric
3209 sensor, essentially measuring the amount of air above the
3210 rocket to figure out how high it is. A large number of
3211 measurements are taken as the altimeter initializes itself to
3212 figure out the pad altitude. Subsequent measurements are then
3213 used to compute the height above the pad.
3216 To accurately measure atmospheric pressure, the ebay
3217 containing the altimeter must be vented outside the
3218 air-frame. The vent must be placed in a region of linear
3219 airflow, have smooth edges, and away from areas of increasing or
3220 decreasing pressure.
3223 All barometric sensors are quite sensitive to chemical damage from
3224 the products of APCP or BP combustion, so make sure the ebay is
3225 carefully sealed from any compartment which contains ejection
3230 <title>Ground Testing</title>
3232 The most important aspect of any installation is careful
3233 ground testing. Bringing an air-frame up to the LCO table which
3234 hasn't been ground tested can lead to delays or ejection
3235 charges firing on the pad, or, even worse, a recovery system
3239 Do a 'full systems' test that includes wiring up all igniters
3240 without any BP and turning on all of the electronics in flight
3241 mode. This will catch any mistakes in wiring and any residual
3242 RFI issues that might accidentally fire igniters at the wrong
3243 time. Let the air-frame sit for several minutes, checking for
3244 adequate telemetry signal strength and GPS lock. If any igniters
3245 fire unexpectedly, find and resolve the issue before loading any
3249 Ground test the ejection charges. Prepare the rocket for
3250 flight, loading ejection charges and igniters. Completely
3251 assemble the air-frame and then use the 'Fire Igniters'
3252 interface through a TeleDongle to command each charge to
3253 fire. Make sure the charge is sufficient to robustly separate
3254 the air-frame and deploy the recovery system.
3259 <title>Updating Device Firmware</title>
3261 TeleMega, TeleMetrum v2 and EasyMini are all programmed directly
3262 over their USB connectors (self programming). TeleMetrum v1, TeleMini and
3263 TeleDongle are all programmed by using another device as a
3264 programmer (pair programming). It's important to recognize which
3265 kind of devices you have before trying to reprogram them.
3268 You may wish to begin by ensuring you have current firmware images.
3269 These are distributed as part of the AltOS software bundle that
3270 also includes the AltosUI ground station program. Newer ground
3271 station versions typically work fine with older firmware versions,
3272 so you don't need to update your devices just to try out new
3273 software features. You can always download the most recent
3274 version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
3277 If you need to update the firmware on a TeleDongle, we recommend
3278 updating the altimeter first, before updating TeleDongle. However,
3279 note that TeleDongle rarely need to be updated. Any firmware version
3280 1.0.1 or later will work, version 1.2.1 may have improved receiver
3281 performance slightly.
3284 Self-programmable devices (TeleMega, TeleMetrum v2 and EasyMini)
3285 are reprogrammed by connecting them to your computer over USB
3289 Updating TeleMega, TeleMetrum v2 or EasyMini Firmware
3291 <orderedlist inheritnum='inherit' numeration='arabic'>
3294 Attach a battery and power switch to the target
3295 device. Power up the device.
3300 Using a Micro USB cable, connect the target device to your
3301 computer's USB socket.
3306 Run AltosUI, and select 'Flash Image' from the File menu.
3311 Select the target device in the Device Selection dialog.
3316 Select the image you want to flash to the device, which
3317 should have a name in the form
3318 <product>-v<product-version>-<software-version>.ihx, such
3319 as TeleMega-v1.0-1.3.0.ihx.
3324 Make sure the configuration parameters are reasonable
3325 looking. If the serial number and/or RF configuration
3326 values aren't right, you'll need to change them.
3331 Hit the 'OK' button and the software should proceed to flash
3332 the device with new firmware, showing a progress bar.
3337 Verify that the device is working by using the 'Configure
3338 Altimeter' item to check over the configuration.
3343 <title>Recovering From Self-Flashing Failure</title>
3345 If the firmware loading fails, it can leave the device
3346 unable to boot. Not to worry, you can force the device to
3347 start the boot loader instead, which will let you try to
3348 flash the device again.
3351 On each device, connecting two pins from one of the exposed
3352 connectors will force the boot loader to start, even if the
3353 regular operating system has been corrupted in some way.
3357 <term>TeleMega</term>
3360 Connect pin 6 and pin 1 of the companion connector. Pin 1
3361 can be identified by the square pad around it, and then
3362 the pins could sequentially across the board. Be very
3363 careful to <emphasis>not</emphasis> short pin 8 to
3364 anything as that is connected directly to the battery. Pin
3365 7 carries 3.3V and the board will crash if that is
3366 connected to pin 1, but shouldn't damage the board.
3371 <term>TeleMetrum v2</term>
3374 Connect pin 6 and pin 1 of the companion connector. Pin 1
3375 can be identified by the square pad around it, and then
3376 the pins could sequentially across the board. Be very
3377 careful to <emphasis>not</emphasis> short pin 8 to
3378 anything as that is connected directly to the battery. Pin
3379 7 carries 3.3V and the board will crash if that is
3380 connected to pin 1, but shouldn't damage the board.
3385 <term>EasyMini</term>
3388 Connect pin 6 and pin 1 of the debug connector, which is
3389 the six holes next to the beeper. Pin 1 can be identified
3390 by the square pad around it, and then the pins could
3391 sequentially across the board, making Pin 6 the one on the
3392 other end of the row.
3400 <title>Pair Programming</title>
3402 The big concept to understand is that you have to use a
3403 TeleMega, TeleMetrum or TeleDongle as a programmer to update a
3404 pair programmed device. Due to limited memory resources in the
3405 cc1111, we don't support programming directly over USB for these
3410 <title>Updating TeleMetrum v1.x Firmware</title>
3411 <orderedlist inheritnum='inherit' numeration='arabic'>
3414 Find the 'programming cable' that you got as part of the starter
3415 kit, that has a red 8-pin MicroMaTch connector on one end and a
3416 red 4-pin MicroMaTch connector on the other end.
3421 Take the 2 screws out of the TeleDongle case to get access
3422 to the circuit board.
3427 Plug the 8-pin end of the programming cable to the
3428 matching connector on the TeleDongle, and the 4-pin end to the
3429 matching connector on the TeleMetrum.
3430 Note that each MicroMaTch connector has an alignment pin that
3431 goes through a hole in the PC board when you have the cable
3437 Attach a battery to the TeleMetrum board.
3442 Plug the TeleDongle into your computer's USB port, and power
3448 Run AltosUI, and select 'Flash Image' from the File menu.
3453 Pick the TeleDongle device from the list, identifying it as the
3459 Select the image you want put on the TeleMetrum, which should have a
3460 name in the form telemetrum-v1.2-1.0.0.ihx. It should be visible
3461 in the default directory, if not you may have to poke around
3462 your system to find it.
3467 Make sure the configuration parameters are reasonable
3468 looking. If the serial number and/or RF configuration
3469 values aren't right, you'll need to change them.
3474 Hit the 'OK' button and the software should proceed to flash
3475 the TeleMetrum with new firmware, showing a progress bar.
3480 Confirm that the TeleMetrum board seems to have updated OK, which you
3481 can do by plugging in to it over USB and using a terminal program
3482 to connect to the board and issue the 'v' command to check
3488 If something goes wrong, give it another try.
3494 <title>Updating TeleMini Firmware</title>
3495 <orderedlist inheritnum='inherit' numeration='arabic'>
3498 You'll need a special 'programming cable' to reprogram the
3499 TeleMini. You can make your own using an 8-pin MicroMaTch
3500 connector on one end and a set of four pins on the other.
3505 Take the 2 screws out of the TeleDongle case to get access
3506 to the circuit board.
3511 Plug the 8-pin end of the programming cable to the matching
3512 connector on the TeleDongle, and the 4-pins into the holes
3513 in the TeleMini circuit board. Note that the MicroMaTch
3514 connector has an alignment pin that goes through a hole in
3515 the PC board when you have the cable oriented correctly, and
3516 that pin 1 on the TeleMini board is marked with a square pad
3517 while the other pins have round pads.
3522 Attach a battery to the TeleMini board.
3527 Plug the TeleDongle into your computer's USB port, and power
3533 Run AltosUI, and select 'Flash Image' from the File menu.
3538 Pick the TeleDongle device from the list, identifying it as the
3544 Select the image you want put on the TeleMini, which should have a
3545 name in the form telemini-v1.0-1.0.0.ihx. It should be visible
3546 in the default directory, if not you may have to poke around
3547 your system to find it.
3552 Make sure the configuration parameters are reasonable
3553 looking. If the serial number and/or RF configuration
3554 values aren't right, you'll need to change them.
3559 Hit the 'OK' button and the software should proceed to flash
3560 the TeleMini with new firmware, showing a progress bar.
3565 Confirm that the TeleMini board seems to have updated OK, which you
3566 can do by configuring it over the radio link through the TeleDongle, or
3567 letting it come up in “flight” mode and listening for telemetry.
3572 If something goes wrong, give it another try.
3578 <title>Updating TeleDongle Firmware</title>
3580 Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
3581 firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
3583 <orderedlist inheritnum='inherit' numeration='arabic'>
3586 Find the 'programming cable' that you got as part of the starter
3587 kit, that has a red 8-pin MicroMaTch connector on one end and a
3588 red 4-pin MicroMaTch connector on the other end.
3593 Find the USB cable that you got as part of the starter kit, and
3594 plug the “mini” end in to the mating connector on TeleMetrum or TeleDongle.
3599 Take the 2 screws out of the TeleDongle case to get access
3600 to the circuit board.
3605 Plug the 8-pin end of the programming cable to the
3606 matching connector on the programmer, and the 4-pin end to the
3607 matching connector on the TeleDongle.
3608 Note that each MicroMaTch connector has an alignment pin that
3609 goes through a hole in the PC board when you have the cable
3615 Attach a battery to the TeleMetrum board if you're using one.
3620 Plug both the programmer and the TeleDongle into your computer's USB
3621 ports, and power up the programmer.
3626 Run AltosUI, and select 'Flash Image' from the File menu.
3631 Pick the programmer device from the list, identifying it as the
3637 Select the image you want put on the TeleDongle, which should have a
3638 name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
3639 in the default directory, if not you may have to poke around
3640 your system to find it.
3645 Make sure the configuration parameters are reasonable
3646 looking. If the serial number and/or RF configuration
3647 values aren't right, you'll need to change them. The TeleDongle
3648 serial number is on the “bottom” of the circuit board, and can
3649 usually be read through the translucent blue plastic case without
3650 needing to remove the board from the case.
3655 Hit the 'OK' button and the software should proceed to flash
3656 the TeleDongle with new firmware, showing a progress bar.
3661 Confirm that the TeleDongle board seems to have updated OK, which you
3662 can do by plugging in to it over USB and using a terminal program
3663 to connect to the board and issue the 'v' command to check
3664 the version, etc. Once you're happy, remove the programming cable
3665 and put the cover back on the TeleDongle.
3670 If something goes wrong, give it another try.
3675 Be careful removing the programming cable from the locking 8-pin
3676 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
3677 screwdriver or knife blade to gently pry the locking ears out
3678 slightly to extract the connector. We used a locking connector on
3679 TeleMetrum to help ensure that the cabling to companion boards
3680 used in a rocket don't ever come loose accidentally in flight.
3685 <title>Hardware Specifications</title>
3688 TeleMega Specifications
3693 Recording altimeter for model rocketry.
3698 Supports dual deployment and four auxiliary pyro channels
3699 (a total of 6 events).
3704 70cm 40mW ham-band transceiver for telemetry down-link.
3709 Barometric pressure sensor good to 100k feet MSL.
3714 1-axis high-g accelerometer for motor characterization, capable of
3720 9-axis IMU including integrated 3-axis accelerometer,
3721 3-axis gyroscope and 3-axis magnetometer.
3726 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
3731 On-board 8 Megabyte non-volatile memory for flight data storage.
3736 USB interface for battery charging, configuration, and data recovery.
3741 Fully integrated support for Li-Po rechargeable batteries.
3746 Can use either main system Li-Po or optional separate pyro battery
3752 3.25 x 1.25 inch board designed to fit inside 38mm air-frame coupler tube.
3759 TeleMetrum v2 Specifications
3764 Recording altimeter for model rocketry.
3769 Supports dual deployment (can fire 2 ejection charges).
3774 70cm, 40mW ham-band transceiver for telemetry down-link.
3779 Barometric pressure sensor good to 100k feet MSL.
3784 1-axis high-g accelerometer for motor characterization, capable of
3790 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
3795 On-board 8 Megabyte non-volatile memory for flight data storage.
3800 USB interface for battery charging, configuration, and data recovery.
3805 Fully integrated support for Li-Po rechargeable batteries.
3810 Uses Li-Po to fire e-matches, can be modified to support
3811 optional separate pyro battery if needed.
3816 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
3822 <title>TeleMetrum v1 Specifications</title>
3826 Recording altimeter for model rocketry.
3831 Supports dual deployment (can fire 2 ejection charges).
3836 70cm, 10mW ham-band transceiver for telemetry down-link.
3841 Barometric pressure sensor good to 45k feet MSL.
3846 1-axis high-g accelerometer for motor characterization, capable of
3847 +/- 50g using default part.
3852 On-board, integrated GPS receiver with 5Hz update rate capability.
3857 On-board 1 megabyte non-volatile memory for flight data storage.
3862 USB interface for battery charging, configuration, and data recovery.
3867 Fully integrated support for Li-Po rechargeable batteries.
3872 Uses Li-Po to fire e-matches, can be modified to support
3873 optional separate pyro battery if needed.
3878 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
3885 TeleMini v2.0 Specifications
3890 Recording altimeter for model rocketry.
3895 Supports dual deployment (can fire 2 ejection charges).
3900 70cm, 10mW ham-band transceiver for telemetry down-link.
3905 Barometric pressure sensor good to 100k feet MSL.
3910 On-board 1 megabyte non-volatile memory for flight data storage.
3915 USB interface for configuration, and data recovery.
3920 Support for Li-Po rechargeable batteries (using an
3921 external charger), or any 3.7-15V external battery.
3926 Uses Li-Po to fire e-matches, can be modified to support
3927 optional separate pyro battery if needed.
3932 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
3939 TeleMini v1.0 Specifications
3944 Recording altimeter for model rocketry.
3949 Supports dual deployment (can fire 2 ejection charges).
3954 70cm, 10mW ham-band transceiver for telemetry down-link.
3959 Barometric pressure sensor good to 45k feet MSL.
3964 On-board 5 kilobyte non-volatile memory for flight data storage.
3969 RF interface for configuration, and data recovery.
3974 Support for Li-Po rechargeable batteries, using an external charger.
3979 Uses Li-Po to fire e-matches, can be modified to support
3980 optional separate pyro battery if needed.
3985 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube.
3992 EasyMini Specifications
3997 Recording altimeter for model rocketry.
4002 Supports dual deployment (can fire 2 ejection charges).
4007 Barometric pressure sensor good to 100k feet MSL.
4012 On-board 1 megabyte non-volatile memory for flight data storage.
4017 USB interface for configuration, and data recovery.
4022 Support for Li-Po rechargeable batteries (using an
4023 external charger), or any 3.7-15V external battery.
4028 Uses Li-Po to fire e-matches, can be modified to support
4029 optional separate pyro battery if needed.
4034 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
4043 <emphasis>TeleMetrum seems to shut off when disconnected from the
4044 computer.</emphasis> <?linebreak?>
4045 Make sure the battery is adequately charged. Remember the
4046 unit will pull more power than the USB port can deliver before the
4047 GPS enters “locked” mode. The battery charges best when TeleMetrum
4051 <emphasis>It's impossible to stop the TeleDongle when it's in “p” mode, I have
4052 to unplug the USB cable? </emphasis><?linebreak?>
4053 Make sure you have tried to “escape out” of
4054 this mode. If this doesn't work the reboot procedure for the
4055 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
4056 outgoing buffer IF your “escape out” ('~~') does not work.
4057 At this point using either 'ao-view' (or possibly
4058 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
4062 <emphasis>The amber LED (on the TeleMetrum) lights up when both
4063 battery and USB are connected. Does this mean it's charging?
4064 </emphasis><?linebreak?>
4065 Yes, the yellow LED indicates the charging at the 'regular' rate.
4066 If the led is out but the unit is still plugged into a USB port,
4067 then the battery is being charged at a 'trickle' rate.
4070 <emphasis>There are no “dit-dah-dah-dit” sound or lights like the manual
4071 mentions?</emphasis><?linebreak?>
4072 That's the “pad” mode. Weak batteries might be the problem.
4073 It is also possible that the flight computer is horizontal and the
4075 is instead a “dit-dit” meaning 'idle'. For TeleMini, it's possible that
4076 it received a command packet which would have left it in “pad” mode.
4079 <emphasis>How do I save flight data?</emphasis><?linebreak?>
4080 Live telemetry is written to file(s) whenever AltosUI is connected
4081 to the TeleDongle. The file area defaults to ~/TeleMetrum
4082 but is easily changed using the menus in AltosUI. The files that
4083 are written end in '.telem'. The after-flight
4084 data-dumped files will end in .eeprom and represent continuous data
4085 unlike the .telem files that are subject to losses
4086 along the RF data path.
4087 See the above instructions on what and how to save the eeprom stored
4088 data after physically retrieving your altimeter. Make sure to save
4089 the on-board data after each flight; while the TeleMetrum can store
4090 multiple flights, you never know when you'll lose the altimeter...
4094 <title>Notes for Older Software</title>
4097 Before AltosUI was written, using Altus Metrum devices required
4098 some finesse with the Linux command line. There was a limited
4099 GUI tool, ao-view, which provided functionality similar to the
4100 Monitor Flight window in AltosUI, but everything else was a
4101 fairly 80's experience. This appendix includes documentation for
4102 using that software.
4106 Both TeleMetrum and TeleDongle can be directly communicated
4107 with using USB ports. The first thing you should try after getting
4108 both units plugged into to your computer's USB port(s) is to run
4109 'ao-list' from a terminal-window to see what port-device-name each
4110 device has been assigned by the operating system.
4111 You will need this information to access the devices via their
4112 respective on-board firmware and data using other command line
4113 programs in the AltOS software suite.
4116 TeleMini can be communicated with through a TeleDongle device
4117 over the radio link. When first booted, TeleMini listens for a
4118 TeleDongle device and if it receives a packet, it goes into
4119 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be
4120 launched. The easiest way to get it talking is to start the
4121 communication link on the TeleDongle and the power up the
4125 To access the device's firmware for configuration you need a terminal
4126 program such as you would use to talk to a modem. The software
4127 authors prefer using the program 'cu' which comes from the UUCP package
4128 on most Unix-like systems such as Linux. An example command line for
4129 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
4130 indicated from running the
4131 ao-list program. Another reasonable terminal program for Linux is
4132 'cutecom'. The default 'escape'
4133 character used by CU (i.e. the character you use to
4134 issue commands to cu itself instead of sending the command as input
4135 to the connected device) is a '~'. You will need this for use in
4136 only two different ways during normal operations. First is to exit
4137 the program by sending a '~.' which is called a 'escape-disconnect'
4138 and allows you to close-out from 'cu'. The
4139 second use will be outlined later.
4142 All of the Altus Metrum devices share the concept of a two level
4143 command set in their firmware.
4144 The first layer has several single letter commands. Once
4145 you are using 'cu' (or 'cutecom') sending (typing) a '?'
4146 returns a full list of these
4147 commands. The second level are configuration sub-commands accessed
4148 using the 'c' command, for
4149 instance typing 'c?' will give you this second level of commands
4150 (all of which require the
4151 letter 'c' to access). Please note that most configuration options
4152 are stored only in Flash memory; TeleDongle doesn't provide any storage
4153 for these options and so they'll all be lost when you unplug it.
4156 Try setting these configuration ('c' or second level menu) values. A good
4157 place to start is by setting your call sign. By default, the boards
4158 use 'N0CALL' which is cute, but not exactly legal!
4159 Spend a few minutes getting comfortable with the units, their
4160 firmware, and 'cu' (or possibly 'cutecom').
4161 For instance, try to send
4162 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
4163 Verify you can connect and disconnect from the units while in your
4164 terminal program by sending the escape-disconnect mentioned above.
4167 To set the radio frequency, use the 'c R' command to specify the
4168 radio transceiver configuration parameter. This parameter is computed
4169 using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
4170 the standard calibration reference frequency, 'S', (normally 434.550MHz):
4174 Round the result to the nearest integer value.
4175 As with all 'c' sub-commands, follow this with a 'c w' to write the
4176 change to the parameter block in the on-board flash on
4177 your altimeter board if you want the change to stay in place across reboots.
4180 To set the apogee delay, use the 'c d' command.
4181 As with all 'c' sub-commands, follow this with a 'c w' to write the
4182 change to the parameter block in the on-board DataFlash chip.
4185 To set the main deployment altitude, use the 'c m' command.
4186 As with all 'c' sub-commands, follow this with a 'c w' to write the
4187 change to the parameter block in the on-board DataFlash chip.
4190 To calibrate the radio frequency, connect the UHF antenna port to a
4191 frequency counter, set the board to 434.550MHz, and use the 'C'
4192 command to generate a CW carrier. Wait for the transmitter temperature
4193 to stabilize and the frequency to settle down.
4194 Then, divide 434.550 MHz by the
4195 measured frequency and multiply by the current radio cal value show
4196 in the 'c s' command. For an unprogrammed board, the default value
4197 is 1186611 for cc1111 based products and 7119667 for cc1120
4198 based products. Take the resulting integer and program it using the 'c f'
4199 command. Testing with the 'C' command again should show a carrier
4200 within a few tens of Hertz of the intended frequency.
4201 As with all 'c' sub-commands, follow this with a 'c w' to write the
4202 change to the configuration memory.
4205 Note that the 'reboot' command, which is very useful on the altimeters,
4206 will likely just cause problems with the dongle. The *correct* way
4207 to reset the dongle is just to unplug and re-plug it.
4210 A fun thing to do at the launch site and something you can do while
4211 learning how to use these units is to play with the radio link access
4212 between an altimeter and the TeleDongle. Be aware that you *must* create
4213 some physical separation between the devices, otherwise the link will
4214 not function due to signal overload in the receivers in each device.
4217 Now might be a good time to take a break and read the rest of this
4218 manual, particularly about the two “modes” that the altimeters
4219 can be placed in. TeleMetrum uses the position of the device when booting
4220 up will determine whether the unit is in “pad” or “idle” mode. TeleMini
4221 enters “idle” mode when it receives a command packet within the first 5 seconds
4222 of being powered up, otherwise it enters “pad” mode.
4225 You can access an altimeter in idle mode from the TeleDongle's USB
4226 connection using the radio link
4227 by issuing a 'p' command to the TeleDongle. Practice connecting and
4228 disconnecting ('~~' while using 'cu') from the altimeter. If
4229 you cannot escape out of the “p” command, (by using a '~~' when in
4230 CU) then it is likely that your kernel has issues. Try a newer version.
4233 Using this radio link allows you to configure the altimeter, test
4234 fire e-matches and igniters from the flight line, check pyro-match
4235 continuity and so forth. You can leave the unit turned on while it
4236 is in 'idle mode' and then place the
4237 rocket vertically on the launch pad, walk away and then issue a
4238 reboot command. The altimeter will reboot and start sending data
4239 having changed to the “pad” mode. If the TeleDongle is not receiving
4240 this data, you can disconnect 'cu' from the TeleDongle using the
4241 procedures mentioned above and THEN connect to the TeleDongle from
4242 inside 'ao-view'. If this doesn't work, disconnect from the
4243 TeleDongle, unplug it, and try again after plugging it back in.
4246 In order to reduce the chance of accidental firing of pyrotechnic
4247 charges, the command to fire a charge is intentionally somewhat
4248 difficult to type, and the built-in help is slightly cryptic to
4249 prevent accidental echoing of characters from the help text back at
4250 the board from firing a charge. The command to fire the apogee
4251 drogue charge is 'i DoIt drogue' and the command to fire the main
4252 charge is 'i DoIt main'.
4255 On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
4256 and 'ao-view' will both auditorily announce and visually indicate
4258 Now you can launch knowing that you have a good data path and
4259 good satellite lock for flight data and recovery. Remember
4260 you MUST tell ao-view to connect to the TeleDongle explicitly in
4261 order for ao-view to be able to receive data.
4264 The altimeters provide RDF (radio direction finding) tones on
4265 the pad, during descent and after landing. These can be used to
4266 locate the rocket using a directional antenna; the signal
4267 strength providing an indication of the direction from receiver to rocket.
4270 TeleMetrum also provides GPS tracking data, which can further simplify
4271 locating the rocket once it has landed. (The last good GPS data
4272 received before touch-down will be on the data screen of 'ao-view'.)
4275 Once you have recovered the rocket you can download the eeprom
4276 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
4277 either a USB cable or over the radio link using TeleDongle.
4278 And by following the man page for 'ao-postflight' you can create
4279 various data output reports, graphs, and even KML data to see the
4280 flight trajectory in Google-earth. (Moving the viewing angle making
4281 sure to connect the yellow lines while in Google-earth is the proper
4285 As for ao-view.... some things are in the menu but don't do anything
4286 very useful. The developers have stopped working on ao-view to focus
4287 on a new, cross-platform ground station program. So ao-view may or
4288 may not be updated in the future. Mostly you just use
4289 the Log and Device menus. It has a wonderful display of the incoming
4290 flight data and I am sure you will enjoy what it has to say to you
4291 once you enable the voice output!
4295 <title>Drill Templates</title>
4297 These images, when printed, provide precise templates for the
4298 mounting holes in Altus Metrum flight computers
4301 <title>TeleMega template</title>
4303 TeleMega has overall dimensions of 1.250 x 3.250 inches, and
4304 the mounting holes are sized for use with 4-40 or M3 screws.
4307 <mediaobject id="TeleMegaTemplate">
4309 <imagedata format="SVG" fileref="telemega-outline.svg"/>
4315 <title>TeleMetrum template</title>
4317 TeleMetrum has overall dimensions of 1.000 x 2.750 inches, and the
4318 mounting holes are sized for use with 4-40 or M3 screws.
4321 <mediaobject id="TeleMetrumTemplate">
4323 <imagedata format="SVG" fileref="telemetrum.svg"/>
4329 <title>TeleMini v2/EasyMini template</title>
4331 TeleMini v2 and EasyMini have overall dimensions of 0.800 x 1.500 inches, and the
4332 mounting holes are sized for use with 4-40 or M3 screws.
4335 <mediaobject id="MiniTemplate">
4337 <imagedata format="SVG" fileref="easymini-outline.svg"/>
4343 <title>TeleMini v1 template</title>
4345 TeleMini has overall dimensions of 0.500 x 1.500 inches, and the
4346 mounting holes are sized for use with 2-56 or M2 screws.
4349 <mediaobject id="TeleMiniTemplate">
4351 <imagedata format="SVG" fileref="telemini.svg"/>
4358 <title>Calibration</title>
4360 There are only two calibrations required for TeleMetrum and
4361 TeleMega, and only one for TeleDongle, TeleMini and EasyMini.
4362 All boards are shipped from the factory pre-calibrated, but
4363 the procedures are documented here in case they are ever
4364 needed. Re-calibration is not supported by AltosUI, you must
4365 connect to the board with a serial terminal program and
4366 interact directly with the on-board command interpreter to
4370 <title>Radio Frequency</title>
4372 The radio frequency is synthesized from a clock based on the
4373 crystal on the board. The actual frequency of this oscillator
4374 must be measured to generate a calibration constant. While our
4376 bandwidth is wide enough to allow boards to communicate even when
4377 their oscillators are not on exactly the same frequency, performance
4378 is best when they are closely matched.
4379 Radio frequency calibration requires a calibrated frequency counter.
4380 Fortunately, once set, the variation in frequency due to aging and
4381 temperature changes is small enough that re-calibration by customers
4382 should generally not be required.
4385 To calibrate the radio frequency, connect the UHF antenna
4386 port to a frequency counter, set the board to 434.550MHz,
4387 and use the 'C' command in the on-board command interpreter
4388 to generate a CW carrier. For USB-enabled boards, this is
4389 best done over USB. For TeleMini v1, note that the only way
4390 to escape the 'C' command is via power cycle since the board
4391 will no longer be listening for commands once it starts
4392 generating a CW carrier.
4395 Wait for the transmitter temperature to stabilize and the frequency
4396 to settle down. Then, divide 434.550 MHz by the
4397 measured frequency and multiply by the current radio cal value show
4398 in the 'c s' command. For an unprogrammed board, the default value
4399 is 1186611. Take the resulting integer and program it using the 'c f'
4400 command. Testing with the 'C' command again should show a carrier
4401 within a few tens of Hertz of the intended frequency.
4402 As with all 'c' sub-commands, follow this with a 'c w' to write the
4403 change to the parameter block in the on-board storage chip.
4406 Note that any time you re-do the radio frequency calibration, the
4407 radio frequency is reset to the default 434.550 Mhz. If you want
4408 to use another frequency, you will have to set that again after
4409 calibration is completed.
4413 <title>TeleMetrum and TeleMega Accelerometers</title>
4415 While barometric sensors are factory-calibrated,
4416 accelerometers are not, and so each must be calibrated once
4417 installed in a flight computer. Explicitly calibrating the
4418 accelerometers also allows us to load any compatible device.
4419 We perform a two-point calibration using gravity.
4422 To calibrate the acceleration sensor, use the 'c a 0' command. You
4423 will be prompted to orient the board vertically with the UHF antenna
4424 up and press a key, then to orient the board vertically with the
4425 UHF antenna down and press a key. Note that the accuracy of this
4426 calibration depends primarily on how perfectly vertical and still
4427 the board is held during the cal process. As with all 'c'
4428 sub-commands, follow this with a 'c w' to write the
4429 change to the parameter block in the on-board DataFlash chip.
4432 The +1g and -1g calibration points are included in each telemetry
4433 frame and are part of the header stored in onboard flash to be
4434 downloaded after flight. We always store and return raw ADC
4435 samples for each sensor... so nothing is permanently “lost” or
4436 “damaged” if the calibration is poor.
4439 In the unlikely event an accel cal goes badly, it is possible
4440 that TeleMetrum or TeleMega may always come up in 'pad mode'
4441 and as such not be listening to either the USB or radio link.
4442 If that happens, there is a special hook in the firmware to
4443 force the board back in to 'idle mode' so you can re-do the
4444 cal. To use this hook, you just need to ground the SPI clock
4445 pin at power-on. This pin is available as pin 2 on the 8-pin
4446 companion connector, and pin 1 is ground. So either
4447 carefully install a fine-gauge wire jumper between the two
4448 pins closest to the index hole end of the 8-pin connector, or
4449 plug in the programming cable to the 8-pin connector and use
4450 a small screwdriver or similar to short the two pins closest
4451 to the index post on the 4-pin end of the programming cable,
4452 and power up the board. It should come up in 'idle mode'
4453 (two beeps), allowing a re-cal.
4458 <title>Release Notes</title>
4460 <title>Version 1.3.1</title>
4462 xmlns:xi="http://www.w3.org/2001/XInclude"
4463 href="release-notes-1.3.1.xsl"
4464 xpointer="xpointer(/article/*)"/>
4467 <title>Version 1.3</title>
4469 xmlns:xi="http://www.w3.org/2001/XInclude"
4470 href="release-notes-1.3.xsl"
4471 xpointer="xpointer(/article/*)"/>
4474 <title>Version 1.2.1</title>
4476 xmlns:xi="http://www.w3.org/2001/XInclude"
4477 href="release-notes-1.2.1.xsl"
4478 xpointer="xpointer(/article/*)"/>
4481 <title>Version 1.2</title>
4483 xmlns:xi="http://www.w3.org/2001/XInclude"
4484 href="release-notes-1.2.xsl"
4485 xpointer="xpointer(/article/*)"/>
4488 <title>Version 1.1.1</title>
4490 xmlns:xi="http://www.w3.org/2001/XInclude"
4491 href="release-notes-1.1.1.xsl"
4492 xpointer="xpointer(/article/*)"/>
4495 <title>Version 1.1</title>
4497 xmlns:xi="http://www.w3.org/2001/XInclude"
4498 href="release-notes-1.1.xsl"
4499 xpointer="xpointer(/article/*)"/>
4502 <title>Version 1.0.1</title>
4504 xmlns:xi="http://www.w3.org/2001/XInclude"
4505 href="release-notes-1.0.1.xsl"
4506 xpointer="xpointer(/article/*)"/>
4509 <title>Version 0.9.2</title>
4511 xmlns:xi="http://www.w3.org/2001/XInclude"
4512 href="release-notes-0.9.2.xsl"
4513 xpointer="xpointer(/article/*)"/>
4516 <title>Version 0.9</title>
4518 xmlns:xi="http://www.w3.org/2001/XInclude"
4519 href="release-notes-0.9.xsl"
4520 xpointer="xpointer(/article/*)"/>
4523 <title>Version 0.8</title>
4525 xmlns:xi="http://www.w3.org/2001/XInclude"
4526 href="release-notes-0.8.xsl"
4527 xpointer="xpointer(/article/*)"/>
4530 <title>Version 0.7.1</title>
4532 xmlns:xi="http://www.w3.org/2001/XInclude"
4533 href="release-notes-0.7.1.xsl"
4534 xpointer="xpointer(/article/*)"/>
4539 <!-- LocalWords: Altusmetrum
projects / fw / altos / blob