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2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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5 <title>The Altus Metrum System</title>
6 <subtitle>An Owner's Manual for Altus Metrum Rocketry Electronics</subtitle>
9 <firstname>Bdale</firstname>
10 <surname>Garbee</surname>
13 <firstname>Keith</firstname>
14 <surname>Packard</surname>
17 <firstname>Bob</firstname>
18 <surname>Finch</surname>
21 <firstname>Anthony</firstname>
22 <surname>Towns</surname>
26 <holder>Bdale Garbee and Keith Packard</holder>
30 This document is released under the terms of the
31 <ulink url="http://creativecommons.org/licenses/by-sa/3.0/">
32 Creative Commons ShareAlike 3.0
39 <revnumber>1.3</revnumber>
40 <date>12 November 2013</date>
42 Updated for software version 1.3. Version 1.3 adds support
43 for TeleMega, TeleMetrum v2.0, TeleMini v2.0 and EasyMini
44 and fixes bugs in AltosUI and the AltOS firmware.
48 <revnumber>1.2.1</revnumber>
49 <date>21 May 2013</date>
51 Updated for software version 1.2. Version 1.2 adds support
52 for TeleBT and AltosDroid. It also adds a few minor features
53 and fixes bugs in AltosUI and the AltOS firmware.
57 <revnumber>1.2</revnumber>
58 <date>18 April 2013</date>
60 Updated for software version 1.2. Version 1.2 adds support
61 for MicroPeak and the MicroPeak USB interface.
65 <revnumber>1.1.1</revnumber>
66 <date>16 September 2012</date>
68 Updated for software version 1.1.1 Version 1.1.1 fixes a few
69 bugs found in version 1.1.
73 <revnumber>1.1</revnumber>
74 <date>13 September 2012</date>
76 Updated for software version 1.1. Version 1.1 has new
77 features but is otherwise compatible with version 1.0.
81 <revnumber>1.0</revnumber>
82 <date>24 August 2011</date>
84 Updated for software version 1.0. Note that 1.0 represents a
85 telemetry format change, meaning both ends of a link
86 (TeleMetrum/TeleMini and TeleDongle) must be updated or
87 communications will fail.
91 <revnumber>0.9</revnumber>
92 <date>18 January 2011</date>
94 Updated for software version 0.9. Note that 0.9 represents a
95 telemetry format change, meaning both ends of a link (TeleMetrum and
96 TeleDongle) must be updated or communications will fail.
100 <revnumber>0.8</revnumber>
101 <date>24 November 2010</date>
102 <revremark>Updated for software version 0.8 </revremark>
107 <title>Acknowledgments</title>
109 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing “The
110 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
111 Kit” which formed the basis of the original Getting Started chapter
112 in this manual. Bob was one of our first customers for a production
113 TeleMetrum, and his continued enthusiasm and contributions
114 are immensely gratifying and highly appreciated!
117 And thanks to Anthony (AJ) Towns for major contributions including
118 the AltosUI graphing and site map code and associated documentation.
119 Free software means that our customers and friends can become our
120 collaborators, and we certainly appreciate this level of
124 Have fun using these products, and we hope to meet all of you
125 out on the rocket flight line somewhere.
128 NAR #87103, TRA #12201
130 Keith Packard, KD7SQG
131 NAR #88757, TRA #12200
136 <title>Introduction and Overview</title>
138 Welcome to the Altus Metrum community! Our circuits and software reflect
139 our passion for both hobby rocketry and Free Software. We hope their
140 capabilities and performance will delight you in every way, but by
141 releasing all of our hardware and software designs under open licenses,
142 we also hope to empower you to take as active a role in our collective
146 The first device created for our community was TeleMetrum, a dual
147 deploy altimeter with fully integrated GPS and radio telemetry
148 as standard features, and a “companion interface” that will
149 support optional capabilities in the future. The latest version
150 of TeleMetrum, v2.0, has all of the same features but with
151 improved sensors and radio to offer increased performance.
154 Our second device was TeleMini, a dual deploy altimeter with
155 radio telemetry and radio direction finding. The first version
156 of this device was only 13mm by 38mm (½ inch by 1½ inches) and
157 could fit easily in an 18mm air-frame. The latest version, v2.0,
158 includes a beeper, USB data download and extended on-board
159 flight logging, along with an improved barometric sensor.
162 TeleMega is our most sophisticated device, including six pyro
163 channels (four of which are fully programmable), integrated GPS,
164 integrated gyroscopes for staging/air-start inhibit and high
165 performance telemetry.
168 EasyMini is a dual-deploy altimeter with logging and built-in
172 TeleDongle was our first ground station, providing a USB to RF
173 interfaces for communicating with the altimeters. Combined with
174 your choice of antenna and notebook computer, TeleDongle and our
175 associated user interface software form a complete ground
176 station capable of logging and displaying in-flight telemetry,
177 aiding rocket recovery, then processing and archiving flight
178 data for analysis and review.
181 For a slightly more portable ground station experience that also
182 provides direct rocket recovery support, TeleBT offers flight
183 monitoring and data logging using a Bluetooth connection between
184 the receiver and an Android device that has the Altos Droid
185 application installed from the Google Play store.
188 More products will be added to the Altus Metrum family over time, and
189 we currently envision that this will be a single, comprehensive manual
190 for the entire product family.
194 <title>Getting Started</title>
196 The first thing to do after you check the inventory of parts in your
197 “starter kit” is to charge the battery.
200 For TeleMetrum and TeleMega, the battery can be charged by plugging it into the
201 corresponding socket of the device and then using the USB
202 cable to plug the flight computer into your computer's USB socket. The
203 on-board circuitry will charge the battery whenever it is plugged
204 in, because the on-off switch does NOT control the
208 On TeleMetrum v1 boards, when the GPS chip is initially
209 searching for satellites, TeleMetrum will consume more current
210 than it can pull from the USB port, so the battery must be
211 attached in order to get satellite lock. Once GPS is locked,
212 the current consumption goes back down enough to enable charging
213 while running. So it's a good idea to fully charge the battery
214 as your first item of business so there is no issue getting and
215 maintaining satellite lock. The yellow charge indicator led
216 will go out when the battery is nearly full and the charger goes
217 to trickle charge. It can take several hours to fully recharge a
218 deeply discharged battery.
221 TeleMetrum v2.0 and TeleMega use a higher power battery charger,
222 allowing them to charge the battery while running the board at
223 maximum power. When the battery is charging, or when the board
224 is consuming a lot of power, the red LED will be lit. When the
225 battery is fully charged, the green LED will be lit. When the
226 battery is damaged or missing, both LEDs will be lit, which
230 The Lithium Polymer TeleMini and EasyMini battery can be charged by
231 disconnecting it from the board and plugging it into a
232 standalone battery charger such as the LipoCharger product
233 included in TeleMini Starter Kits, and connecting that via a USB
234 cable to a laptop or other USB power source.
237 You can also choose to use another battery with TeleMini v2.0
238 and EasyMini, anything supplying between 4 and 12 volts should
239 work fine (like a standard 9V battery), but if you are planning
240 to fire pyro charges, ground testing is required to verify that
241 the battery supplies enough current.
244 The other active device in the starter kit is the TeleDongle USB to
245 RF interface. If you plug it in to your Mac or Linux computer it should
246 “just work”, showing up as a serial port device. Windows systems need
247 driver information that is part of the AltOS download to know that the
248 existing USB modem driver will work. We therefore recommend installing
249 our software before plugging in TeleDongle if you are using a Windows
250 computer. If you are using Linux and are having problems, try moving
251 to a fresher kernel (2.6.33 or newer), as the USB serial driver had
252 ugly bugs in some earlier versions.
255 Next you should obtain and install the AltOS software. These
256 include the AltosUI ground station program, current firmware
257 images for all of the hardware, and a number of standalone
258 utilities that are rarely needed. Pre-built binary packages are
259 available for Linux, Microsoft Windows, and recent MacOSX
260 versions. Full source code and build instructions are also
261 available. The latest version may always be downloaded from
262 <ulink url="http://altusmetrum.org/AltOS"/>.
265 If you're using a TeleBT instead of the TeleDongle, you'll want
266 to go install the Altos Droid application from the Google Play
267 store. You don't need a data plan to use Altos Droid, but
268 without network access, the Map view will be less useful as it
269 won't contain any map data. You can also use TeleBT connected
270 over USB with your laptop computer; it acts exactly like a
271 TeleDongle. Anywhere this manual talks about TeleDongle, you can
272 also read that as 'and TeleBT when connected via USB'.
276 <title>Handling Precautions</title>
278 All Altus Metrum products are sophisticated electronic devices.
279 When handled gently and properly installed in an air-frame, they
280 will deliver impressive results. However, as with all electronic
281 devices, there are some precautions you must take.
284 The Lithium Polymer rechargeable batteries have an
285 extraordinary power density. This is great because we can fly with
286 much less battery mass than if we used alkaline batteries or previous
287 generation rechargeable batteries... but if they are punctured
288 or their leads are allowed to short, they can and will release their
290 Thus we recommend that you take some care when handling our batteries
291 and consider giving them some extra protection in your air-frame. We
292 often wrap them in suitable scraps of closed-cell packing foam before
293 strapping them down, for example.
296 The barometric sensors used on all of our flight computers are
297 sensitive to sunlight. In normal mounting situations, the baro sensor
298 and all of the other surface mount components
299 are “down” towards whatever the underlying mounting surface is, so
300 this is not normally a problem. Please consider this, though, when
301 designing an installation, for example, in an air-frame with a
302 see-through plastic payload bay. It is particularly important to
303 consider this with TeleMini v1.0, both because the baro sensor is on the
304 “top” of the board, and because many model rockets with payload bays
305 use clear plastic for the payload bay! Replacing these with an opaque
306 cardboard tube, painting them, or wrapping them with a layer of masking
307 tape are all reasonable approaches to keep the sensor out of direct
311 The barometric sensor sampling port must be able to “breathe”,
312 both by not being covered by foam or tape or other materials that might
313 directly block the hole on the top of the sensor, and also by having a
314 suitable static vent to outside air.
317 As with all other rocketry electronics, Altus Metrum altimeters must
318 be protected from exposure to corrosive motor exhaust and ejection
323 <title>Altus Metrum Hardware</title>
325 <title>Overview</title>
327 Here's the full set of Altus Metrum products, both in
328 production and retired.
331 <title>Altus Metrum Electronics</title>
332 <?dbfo keep-together="always"?>
333 <tgroup cols='8' align='center' colsep='1' rowsep='1'>
334 <colspec align='center' colwidth='*' colname='Device'/>
335 <colspec align='center' colwidth='*' colname='Barometer'/>
336 <colspec align='center' colwidth='*' colname='Z-axis accelerometer'/>
337 <colspec align='center' colwidth='*' colname='GPS'/>
338 <colspec align='center' colwidth='*' colname='3D sensors'/>
339 <colspec align='center' colwidth='*' colname='Storage'/>
340 <colspec align='center' colwidth='*' colname='RF'/>
341 <colspec align='center' colwidth='*' colname='Battery'/>
344 <entry align='center'>Device</entry>
345 <entry align='center'>Barometer</entry>
346 <entry align='center'>Z-axis accelerometer</entry>
347 <entry align='center'>GPS</entry>
348 <entry align='center'>3D sensors</entry>
349 <entry align='center'>Storage</entry>
350 <entry align='center'>RF Output</entry>
351 <entry align='center'>Battery</entry>
356 <entry>TeleMetrum v1.0</entry>
357 <entry><para>MP3H6115 10km (33k')</para></entry>
358 <entry><para>MMA2202 50g</para></entry>
359 <entry>SkyTraq</entry>
366 <entry>TeleMetrum v1.1</entry>
367 <entry><para>MP3H6115 10km (33k')</para></entry>
368 <entry><para>MMA2202 50g</para></entry>
369 <entry>SkyTraq</entry>
376 <entry>TeleMetrum v1.2</entry>
377 <entry><para>MP3H6115 10km (33k')</para></entry>
378 <entry><para>ADXL78 70g</para></entry>
379 <entry>SkyTraq</entry>
386 <entry>TeleMetrum v2.0</entry>
387 <entry><para>MS5607 30km (100k')</para></entry>
388 <entry><para>MMA6555 102g</para></entry>
389 <entry>uBlox Max-7Q</entry>
396 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
397 <entry><para>MP3H6115 10km (33k')</para></entry>
406 <entry>TeleMini <?linebreak?>v2.0</entry>
407 <entry><para>MS5607 30km (100k')</para></entry>
413 <entry>3.7-12V</entry>
416 <entry>EasyMini <?linebreak?>v1.0</entry>
417 <entry><para>MS5607 30km (100k')</para></entry>
423 <entry>3.7-12V</entry>
426 <entry>TeleMega <?linebreak?>v1.0</entry>
427 <entry><para>MS5607 30km (100k')</para></entry>
428 <entry><para>MMA6555 102g</para></entry>
429 <entry>uBlox Max-7Q</entry>
430 <entry><para>MPU6000 HMC5883</para></entry>
439 <title>Altus Metrum Boards</title>
440 <?dbfo keep-together="always"?>
441 <tgroup cols='6' align='center' colsep='1' rowsep='1'>
442 <colspec align='center' colwidth='*' colname='Device'/>
443 <colspec align='center' colwidth='*' colname='Connectors'/>
444 <colspec align='center' colwidth='*' colname='Screw Terminals'/>
445 <colspec align='center' colwidth='*' colname='Width'/>
446 <colspec align='center' colwidth='*' colname='Length'/>
447 <colspec align='center' colwidth='*' colname='Tube Size'/>
450 <entry align='center'>Device</entry>
451 <entry align='center'>Connectors</entry>
452 <entry align='center'>Screw Terminals</entry>
453 <entry align='center'>Width</entry>
454 <entry align='center'>Length</entry>
455 <entry align='center'>Tube Size</entry>
460 <entry>TeleMetrum</entry>
464 Companion<?linebreak?>
468 <entry><para>Apogee pyro <?linebreak?>Main pyro <?linebreak?>Switch</para></entry>
469 <entry>1 inch (2.54cm)</entry>
470 <entry>2 ¾ inch (6.99cm)</entry>
471 <entry>29mm coupler</entry>
474 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
481 Apogee pyro <?linebreak?>
484 <entry>½ inch (1.27cm)</entry>
485 <entry>1½ inch (3.81cm)</entry>
486 <entry>18mm airframe</entry>
489 <entry>TeleMini <?linebreak?>v2.0</entry>
497 Apogee pyro <?linebreak?>
498 Main pyro <?linebreak?>
499 Battery <?linebreak?>
502 <entry>0.8 inch (2.03cm)</entry>
503 <entry>1½ inch (3.81cm)</entry>
504 <entry>24mm coupler</entry>
507 <entry>EasyMini</entry>
514 Apogee pyro <?linebreak?>
515 Main pyro <?linebreak?>
516 Battery <?linebreak?>
519 <entry>0.8 inch (2.03cm)</entry>
520 <entry>1½ inch (3.81cm)</entry>
521 <entry>24mm coupler</entry>
524 <entry>TeleMega</entry>
528 Companion<?linebreak?>
533 Apogee pyro <?linebreak?>
534 Main pyro<?linebreak?>
535 Pyro A-D<?linebreak?>
539 <entry>1¼ inch (3.18cm)</entry>
540 <entry>3¼ inch (8.26cm)</entry>
541 <entry>38mm coupler</entry>
548 <title>TeleMetrum</title>
551 <imagedata fileref="telemetrum-v1.1-thside.jpg" width="5.5in" scalefit="1"/>
555 TeleMetrum is a 1 inch by 2¾ inch circuit board. It was designed to
556 fit inside coupler for 29mm air-frame tubing, but using it in a tube that
557 small in diameter may require some creativity in mounting and wiring
558 to succeed! The presence of an accelerometer means TeleMetrum should
559 be aligned along the flight axis of the airframe, and by default the ¼
560 wave UHF wire antenna should be on the nose-cone end of the board. The
561 antenna wire is about 7 inches long, and wiring for a power switch and
562 the e-matches for apogee and main ejection charges depart from the
563 fin can end of the board, meaning an ideal “simple” avionics
564 bay for TeleMetrum should have at least 10 inches of interior length.
568 <title>TeleMini</title>
571 <imagedata fileref="telemini-v1-top.jpg" width="5.5in" scalefit="1"/>
575 TeleMini v1.0 is ½ inches by 1½ inches. It was
576 designed to fit inside an 18mm air-frame tube, but using it in
577 a tube that small in diameter may require some creativity in
578 mounting and wiring to succeed! Since there is no
579 accelerometer, TeleMini can be mounted in any convenient
580 orientation. The default ¼ wave UHF wire antenna attached to
581 the center of one end of the board is about 7 inches long. Two
582 wires for the power switch are connected to holes in the
583 middle of the board. Screw terminals for the e-matches for
584 apogee and main ejection charges depart from the other end of
585 the board, meaning an ideal “simple” avionics bay for TeleMini
586 should have at least 9 inches of interior length.
590 <imagedata fileref="telemini-v2-top.jpg" width="5.5in" scalefit="1"/>
594 TeleMini v2.0 is 0.8 inches by 1½ inches. It adds more
595 on-board data logging memory, a built-in USB connector and
596 screw terminals for the battery and power switch. The larger
597 board fits in a 24mm coupler. There's also a battery connector
598 for a LiPo battery if you want to use one of those.
602 <title>EasyMini</title>
605 <imagedata fileref="easymini-top.jpg" width="5.5in" scalefit="1"/>
609 EasyMini is built on a 0.8 inch by 1½ inch circuit board. It's
610 designed to fit in a 24mm coupler tube. The connectors and
611 screw terminals match TeleMini, so you can swap an EasyMini
616 <title>TeleMega</title>
619 <imagedata fileref="telemega-v1.0-top.jpg" width="5.5in" scalefit="1"/>
623 TeleMega is a 1¼ inch by 3¼ inch circuit board. It was
624 designed to easily fit in a 38mm coupler. Like TeleMetrum,
625 TeleMega has an accelerometer and so it must be mounted so that
626 the board is aligned with the flight axis. It can be mounted
627 either antenna up or down.
631 <title>Flight Data Recording</title>
633 Each flight computer logs data at 100 samples per second
634 during ascent and 10 samples per second during descent, except
635 for TeleMini v1.0, which records ascent at 10 samples per
636 second and descent at 1 sample per second. Data are logged to
637 an on-board flash memory part, which can be partitioned into
638 several equal-sized blocks, one for each flight.
641 <title>Data Storage on Altus Metrum altimeters</title>
642 <?dbfo keep-together="always"?>
643 <tgroup cols='4' align='center' colsep='1' rowsep='1'>
644 <colspec align='center' colwidth='*' colname='Device'/>
645 <colspec align='center' colwidth='*' colname='Bytes per sample'/>
646 <colspec align='center' colwidth='*' colname='Total storage'/>
647 <colspec align='center' colwidth='*' colname='Minutes of
651 <entry align='center'>Device</entry>
652 <entry align='center'>Bytes per Sample</entry>
653 <entry align='center'>Total Storage</entry>
654 <entry align='center'>Minutes at Full Rate</entry>
659 <entry>TeleMetrum v1.0</entry>
665 <entry>TeleMetrum v1.1 v1.2</entry>
671 <entry>TeleMetrum v2.0</entry>
677 <entry>TeleMini v1.0</entry>
683 <entry>TeleMini v2.0</entry>
689 <entry>EasyMini</entry>
695 <entry>TeleMega</entry>
704 The on-board flash is partitioned into separate flight logs,
705 each of a fixed maximum size. Increase the maximum size of
706 each log and you reduce the number of flights that can be
707 stored. Decrease the size and you can store more flights.
710 Configuration data is also stored in the flash memory on
711 TeleMetrum v1.x, TeleMini and EasyMini. This consumes 64kB
712 of flash space. This configuration space is not available
713 for storing flight log data. TeleMetrum v2.0 and TeleMega
714 store configuration data in a bit of eeprom available within
715 the processor chip, leaving that space available in flash for
719 To compute the amount of space needed for a single flight, you
720 can multiply the expected ascent time (in seconds) by 100
721 times bytes-per-sample, multiply the expected descent time (in
722 seconds) by 10 times the bytes per sample and add the two
723 together. That will slightly under-estimate the storage (in
724 bytes) needed for the flight. For instance, a TeleMetrum v2.0 flight spending
725 20 seconds in ascent and 150 seconds in descent will take
726 about (20 * 1600) + (150 * 160) = 56000 bytes of storage. You
727 could store dozens of these flights in the on-board flash.
730 The default size allows for several flights on each flight
731 computer, except for TeleMini v1.0, which only holds data for a
732 single flight. You can adjust the size.
735 Altus Metrum flight computers will not overwrite existing
736 flight data, so be sure to download flight data and erase it
737 from the flight computer before it fills up. The flight
738 computer will still successfully control the flight even if it
739 cannot log data, so the only thing you will lose is the data.
743 <title>Installation</title>
745 A typical installation involves attaching
746 only a suitable battery, a single pole switch for
747 power on/off, and two pairs of wires connecting e-matches for the
748 apogee and main ejection charges. All Altus Metrum products are
749 designed for use with single-cell batteries with 3.7 volts
750 nominal. TeleMini v2.0 and EasyMini may also be used with other
751 batteries as long as they supply between 4 and 12 volts.
754 The battery connectors are a standard 2-pin JST connector and
755 match batteries sold by Spark Fun. These batteries are
756 single-cell Lithium Polymer batteries that nominally provide 3.7
757 volts. Other vendors sell similar batteries for RC aircraft
758 using mating connectors, however the polarity for those is
759 generally reversed from the batteries used by Altus Metrum
760 products. In particular, the Tenergy batteries supplied for use
761 in Featherweight flight computers are not compatible with Altus
762 Metrum flight computers or battery chargers. <emphasis>Check
763 polarity and voltage before connecting any battery not purchased
764 from Altus Metrum or Spark Fun.</emphasis>
767 By default, we use the unregulated output of the battery directly
768 to fire ejection charges. This works marvelously with standard
769 low-current e-matches like the J-Tek from MJG Technologies, and with
770 Quest Q2G2 igniters. However, if you want or need to use a separate
771 pyro battery, check out the “External Pyro Battery” section in this
772 manual for instructions on how to wire that up. The altimeters are
773 designed to work with an external pyro battery of no more than 15 volts.
777 Ejection charges are wired directly to the screw terminal block
778 at the aft end of the altimeter. You'll need a very small straight
779 blade screwdriver for these screws, such as you might find in a
780 jeweler's screwdriver set.
783 Except for TeleMini v1.0, the flight computers also use the
784 screw terminal block for the power switch leads. On TeleMini v1.0,
785 the power switch leads are soldered directly to the board and
786 can be connected directly to a switch.
789 For most air-frames, the integrated antennas are more than
790 adequate. However, if you are installing in a carbon-fiber or
791 metal electronics bay which is opaque to RF signals, you may need to
792 use off-board external antennas instead. In this case, you can
793 order an altimeter with an SMA connector for the UHF antenna
794 connection, and, on TeleMetrum v1, you can unplug the integrated GPS
795 antenna and select an appropriate off-board GPS antenna with
796 cable terminating in a U.FL connector.
801 <title>System Operation</title>
803 <title>Firmware Modes </title>
805 The AltOS firmware build for the altimeters has two
806 fundamental modes, “idle” and “flight”. Which of these modes
807 the firmware operates in is determined at start up time. For
808 TeleMetrum, the mode is controlled by the orientation of the
809 rocket (well, actually the board, of course...) at the time
810 power is switched on. If the rocket is “nose up”, then
811 TeleMetrum assumes it's on a rail or rod being prepared for
812 launch, so the firmware chooses flight mode. However, if the
813 rocket is more or less horizontal, the firmware instead enters
814 idle mode. Since TeleMini v2.0 and EasyMini don't have an
815 accelerometer we can use to determine orientation, “idle” mode
816 is selected if the board is connected via USB to a computer,
817 otherwise the board enters “flight” mode. TeleMini v1.0
818 selects “idle” mode if it receives a command packet within the
819 first five seconds of operation.
822 At power on, you will hear three beeps or see three flashes
823 (“S” in Morse code for start up) and then a pause while
824 the altimeter completes initialization and self test, and decides
825 which mode to enter next.
828 In flight or “pad” mode, the altimeter engages the flight
829 state machine, goes into transmit-only mode to
830 send telemetry, and waits for launch to be detected.
831 Flight mode is indicated by an “di-dah-dah-dit” (“P” for pad)
832 on the beeper or lights, followed by beeps or flashes
833 indicating the state of the pyrotechnic igniter continuity.
834 One beep/flash indicates apogee continuity, two beeps/flashes
835 indicate main continuity, three beeps/flashes indicate both
836 apogee and main continuity, and one longer “brap” sound or
837 rapidly alternating lights indicates no continuity. For a
838 dual deploy flight, make sure you're getting three beeps or
839 flashes before launching! For apogee-only or motor eject
840 flights, do what makes sense.
843 If idle mode is entered, you will hear an audible “di-dit” or
844 see two short flashes (“I” for idle), and the flight state
845 machine is disengaged, thus no ejection charges will fire.
846 The altimeters also listen for the radio link when in idle
847 mode for requests sent via TeleDongle. Commands can be issued
848 in idle mode over either USB or the radio link
849 equivalently. TeleMini v1.0 only has the radio link. Idle
850 mode is useful for configuring the altimeter, for extracting
851 data from the on-board storage chip after flight, and for
852 ground testing pyro charges.
855 One “neat trick” of particular value when TeleMetrum or TeleMega are used with
856 very large air-frames, is that you can power the board up while the
857 rocket is horizontal, such that it comes up in idle mode. Then you can
858 raise the air-frame to launch position, and issue a 'reset' command
859 via TeleDongle over the radio link to cause the altimeter to reboot and
860 come up in flight mode. This is much safer than standing on the top
861 step of a rickety step-ladder or hanging off the side of a launch
862 tower with a screw-driver trying to turn on your avionics before
866 TeleMini v1.0 is configured solely via the radio link. Of course, that
867 means you need to know the TeleMini radio configuration values
868 or you won't be able to communicate with it. For situations
869 when you don't have the radio configuration values, TeleMini v1.0
870 offers an 'emergency recovery' mode. In this mode, TeleMini is
871 configured as follows:
875 Sets the radio frequency to 434.550MHz
880 Sets the radio calibration back to the factory value.
885 Sets the callsign to N0CALL
890 Does not go to 'pad' mode after five seconds.
896 To get into 'emergency recovery' mode, first find the row of
897 four small holes opposite the switch wiring. Using a short
898 piece of small gauge wire, connect the outer two holes
899 together, then power TeleMini up. Once the red LED is lit,
900 disconnect the wire and the board should signal that it's in
901 'idle' mode after the initial five second startup period.
907 TeleMetrum and TeleMega include a complete GPS receiver. A
908 complete explanation of how GPS works is beyond the scope of
909 this manual, but the bottom line is that the GPS receiver
910 needs to lock onto at least four satellites to obtain a solid
911 3 dimensional position fix and know what time it is.
914 The flight computers provide backup power to the GPS chip any time a
915 battery is connected. This allows the receiver to “warm start” on
916 the launch rail much faster than if every power-on were a GPS
917 “cold start”. In typical operations, powering up
918 on the flight line in idle mode while performing final air-frame
919 preparation will be sufficient to allow the GPS receiver to cold
920 start and acquire lock. Then the board can be powered down during
921 RSO review and installation on a launch rod or rail. When the board
922 is turned back on, the GPS system should lock very quickly, typically
923 long before igniter installation and return to the flight line are
928 <title>Controlling An Altimeter Over The Radio Link</title>
930 One of the unique features of the Altus Metrum system is the
931 ability to create a two way command link between TeleDongle
932 and an altimeter using the digital radio transceivers
933 built into each device. This allows you to interact with the
934 altimeter from afar, as if it were directly connected to the
938 Any operation which can be performed with a flight computer can
939 either be done with the device directly connected to the
940 computer via the USB cable, or through the radio
941 link. TeleMini v1.0 doesn't provide a USB connector and so it is
942 always communicated with over radio. Select the appropriate
943 TeleDongle device when the list of devices is presented and
944 AltosUI will interact with an altimeter over the radio link.
947 One oddity in the current interface is how AltosUI selects the
948 frequency for radio communications. Instead of providing
949 an interface to specifically configure the frequency, it uses
950 whatever frequency was most recently selected for the target
951 TeleDongle device in Monitor Flight mode. If you haven't ever
952 used that mode with the TeleDongle in question, select the
953 Monitor Flight button from the top level UI, and pick the
954 appropriate TeleDongle device. Once the flight monitoring
955 window is open, select the desired frequency and then close it
956 down again. All radio communications will now use that frequency.
961 Save Flight Data—Recover flight data from the rocket without
967 Configure altimeter apogee delays, main deploy heights
968 and additional pyro event conditions
969 to respond to changing launch conditions. You can also
970 'reboot' the altimeter. Use this to remotely enable the
971 flight computer by turning TeleMetrum or TeleMega on in “idle” mode,
972 then once the air-frame is oriented for launch, you can
973 reboot the altimeter and have it restart in pad mode
974 without having to climb the scary ladder.
979 Fire Igniters—Test your deployment charges without snaking
980 wires out through holes in the air-frame. Simply assemble the
981 rocket as if for flight with the apogee and main charges
982 loaded, then remotely command the altimeter to fire the
988 Operation over the radio link for configuring an altimeter, ground
989 testing igniters, and so forth uses the same RF frequencies as flight
990 telemetry. To configure the desired TeleDongle frequency, select
991 the monitor flight tab, then use the frequency selector and
992 close the window before performing other desired radio operations.
995 The flight computers only enable radio commanding in 'idle' mode.
996 TeleMetrum and TeleMega use the accelerometer to detect which orientation they
997 start up in, so make sure you have the flight computer lying horizontally when you turn
998 it on. Otherwise, it will start in 'pad' mode ready for
999 flight, and will not be listening for command packets from TeleDongle.
1002 TeleMini listens for a command packet for five seconds after
1003 first being turned on, if it doesn't hear anything, it enters
1004 'pad' mode, ready for flight and will no longer listen for
1005 command packets. The easiest way to connect to TeleMini is to
1006 initiate the command and select the TeleDongle device. At this
1007 point, the TeleDongle will be attempting to communicate with
1008 the TeleMini. Now turn TeleMini on, and it should immediately
1009 start communicating with the TeleDongle and the desired
1010 operation can be performed.
1013 You can monitor the operation of the radio link by watching the
1014 lights on the devices. The red LED will flash each time a packet
1015 is transmitted, while the green LED will light up on TeleDongle when
1016 it is waiting to receive a packet from the altimeter.
1020 <title>Ground Testing </title>
1022 An important aspect of preparing a rocket using electronic deployment
1023 for flight is ground testing the recovery system. Thanks
1024 to the bi-directional radio link central to the Altus Metrum system,
1025 this can be accomplished in a TeleMega, TeleMetrum or TeleMini equipped rocket
1026 with less work than you may be accustomed to with other systems. It
1030 Just prep the rocket for flight, then power up the altimeter
1031 in “idle” mode (placing air-frame horizontal for TeleMetrum or TeleMega, or
1032 selecting the Configure Altimeter tab for TeleMini). This will cause
1033 the firmware to go into “idle” mode, in which the normal flight
1034 state machine is disabled and charges will not fire without
1035 manual command. You can now command the altimeter to fire the apogee
1036 or main charges from a safe distance using your computer and
1037 TeleDongle and the Fire Igniter tab to complete ejection testing.
1041 <title>Radio Link </title>
1043 The chip our boards are based on incorporates an RF transceiver, but
1044 it's not a full duplex system... each end can only be transmitting or
1045 receiving at any given moment. So we had to decide how to manage the
1049 By design, the altimeter firmware listens for the radio link when
1050 it's in “idle mode”, which
1051 allows us to use the radio link to configure the rocket, do things like
1052 ejection tests, and extract data after a flight without having to
1053 crack open the air-frame. However, when the board is in “flight
1054 mode”, the altimeter only
1055 transmits and doesn't listen at all. That's because we want to put
1056 ultimate priority on event detection and getting telemetry out of
1058 the radio in case the rocket crashes and we aren't able to extract
1062 We don't generally use a 'normal packet radio' mode like APRS
1063 because they're just too inefficient. The GFSK modulation we
1064 use is FSK with the base-band pulses passed through a Gaussian
1065 filter before they go into the modulator to limit the
1066 transmitted bandwidth. When combined with forward error
1067 correction and interleaving, this allows us to have a very
1068 robust 19.2 kilobit data link with only 10-40 milliwatts of
1069 transmit power, a whip antenna in the rocket, and a hand-held
1070 Yagi on the ground. We've had flights to above 21k feet AGL
1071 with great reception, and calculations suggest we should be
1072 good to well over 40k feet AGL with a 5-element yagi on the
1073 ground with our 10mW units and over 100k feet AGL with the
1074 40mW devices. We hope to fly boards to higher altitudes over
1075 time, and would of course appreciate customer feedback on
1076 performance in higher altitude flights!
1079 TeleMetrum v2.0 and TeleMega can send APRS if desired, the
1080 interval between APRS packets can be configured. As each APRS
1081 packet takes a full second to transmit, we recommend an
1082 interval of at least 5 seconds to avoid consuming too much
1083 battery power or radio channel bandwidth.
1087 <title>Configurable Parameters</title>
1089 Configuring an Altus Metrum altimeter for flight is very
1090 simple. Even on our baro-only TeleMini and EasyMini boards, the use of a Kalman
1091 filter means there is no need to set a “mach delay”. The few
1092 configurable parameters can all be set using AltosUI over USB or
1093 or radio link via TeleDongle.
1096 <title>Radio Frequency</title>
1098 Altus Metrum boards support radio frequencies in the 70cm
1099 band. By default, the configuration interface provides a
1100 list of 10 “standard” frequencies in 100kHz channels starting at
1101 434.550MHz. However, the firmware supports use of
1102 any 50kHz multiple within the 70cm band. At any given
1103 launch, we highly recommend coordinating when and by whom each
1104 frequency will be used to avoid interference. And of course, both
1105 altimeter and TeleDongle must be configured to the same
1106 frequency to successfully communicate with each other.
1110 <title>Apogee Delay</title>
1112 Apogee delay is the number of seconds after the altimeter detects flight
1113 apogee that the drogue charge should be fired. In most cases, this
1114 should be left at the default of 0. However, if you are flying
1115 redundant electronics such as for an L3 certification, you may wish
1116 to set one of your altimeters to a positive delay so that both
1117 primary and backup pyrotechnic charges do not fire simultaneously.
1120 The Altus Metrum apogee detection algorithm fires exactly at
1121 apogee. If you are also flying an altimeter like the
1122 PerfectFlite MAWD, which only supports selecting 0 or 1
1123 seconds of apogee delay, you may wish to set the MAWD to 0
1124 seconds delay and set the TeleMetrum to fire your backup 2
1125 or 3 seconds later to avoid any chance of both charges
1126 firing simultaneously. We've flown several air-frames this
1127 way quite happily, including Keith's successful L3 cert.
1131 <title>Main Deployment Altitude</title>
1133 By default, the altimeter will fire the main deployment charge at an
1134 elevation of 250 meters (about 820 feet) above ground. We think this
1135 is a good elevation for most air-frames, but feel free to change this
1136 to suit. In particular, if you are flying two altimeters, you may
1138 deployment elevation for the backup altimeter to be something lower
1139 than the primary so that both pyrotechnic charges don't fire
1144 <title>Maximum Flight Log</title>
1146 Changing this value will set the maximum amount of flight
1147 log storage that an individual flight will use. The
1148 available storage is divided into as many flights of the
1149 specified size as can fit in the available space. You can
1150 download and erase individual flight logs. If you fill up
1151 the available storage, future flights will not get logged
1152 until you erase some of the stored ones.
1156 <title>Ignite Mode</title>
1158 Instead of firing one charge at apogee and another charge at
1159 a fixed height above the ground, you can configure the
1160 altimeter to fire both at apogee or both during
1161 descent. This was added to support an airframe that has two
1162 altimeters, one in the fin can and one in the
1166 Providing the ability to use both igniters for apogee or
1167 main allows some level of redundancy without needing two
1168 flight computers. In Redundant Apogee or Redundant Main
1169 mode, the two charges will be fired two seconds apart.
1173 <title>Pad Orientation</title>
1175 TeleMetrum and TeleMega measure acceleration along the axis
1176 of the board. Which way the board is oriented affects the
1177 sign of the acceleration value. Instead of trying to guess
1178 which way the board is mounted in the air frame, the
1179 altimeter must be explicitly configured for either Antenna
1180 Up or Antenna Down. The default, Antenna Up, expects the end
1181 of the board connected to the 70cm antenna to be nearest the
1182 nose of the rocket, with the end containing the screw
1183 terminals nearest the tail.
1187 <title>Pyro Channels</title>
1189 In addition to the usual Apogee and Main pyro channels,
1190 TeleMega has four additional channels that can be configured
1191 to activate when various flight conditions are
1192 satisfied. You can select as many conditions as necessary;
1193 all of them must be met in order to activate the
1194 channel. The conditions available are:
1199 Acceleration away from the ground. Select a value, and
1200 then choose whether acceleration should be above or
1201 below that value. Acceleration is positive upwards, so
1202 accelerating towards the ground would produce negative
1203 numbers. Acceleration during descent is noisy and
1204 inaccurate, so be careful when using it during these
1205 phases of the flight.
1210 Vertical speed. Select a value, and then choose whether
1211 vertical speed should be above or below that
1212 value. Speed is positive upwards, so moving towards the
1213 ground would produce negative numbers. Speed during
1214 descent is a bit noisy and so be careful when using it
1215 during these phases of the flight.
1220 Height. Select a value, and then choose whether the
1221 height above the launch pad should be above or below
1227 Orientation. TeleMega contains a 3-axis gyroscope and
1228 accelerometer which is used to measure the current
1229 angle. Note that this angle is not the change in angle
1230 from the launch pad, but rather absolute relative to
1231 gravity; the 3-axis accelerometer is used to compute the
1232 angle of the rocket on the launch pad and initialize the
1233 system. Because this value is computed by integrating
1234 rate gyros, it gets progressively less accurate as the
1235 flight goes on. It should have an accumulated error of
1236 less than .2°/second (after 10 seconds of flight, the
1237 error should be less than 2°).
1240 The usual use of the orientation configuration is to
1241 ensure that the rocket is traveling mostly upwards when
1242 deciding whether to ignite air starts or additional
1243 stages. For that, choose a reasonable maximum angle
1244 (like 20°) and set the motor igniter to require an angle
1245 of less than that value.
1250 Flight Time. Time since boost was detected. Select a
1251 value and choose whether to activate the pyro channel
1252 before or after that amount of time.
1257 Ascending. A simple test saying whether the rocket is
1258 going up or not. This is exactly equivalent to testing
1259 whether the speed is > 0.
1264 Descending. A simple test saying whether the rocket is
1265 going down or not. This is exactly equivalent to testing
1266 whether the speed is < 0.
1271 After Motor. The flight software counts each time the
1272 rocket starts accelerating (presumably due to a motor or
1273 motors igniting). Use this value to count ignitions for
1274 multi-staged or multi-airstart launches.
1279 Delay. This value doesn't perform any checks, instead it
1280 inserts a delay between the time when the other
1281 parameters become true and when the pyro channel is
1287 Flight State. The flight software tracks the flight
1288 through a sequence of states:
1292 Boost. The motor has lit and the rocket is
1293 accelerating upwards.
1298 Fast. The motor has burned out and the rocket is
1299 descellerating, but it is going faster than 200m/s.
1304 Coast. The rocket is still moving upwards and
1305 decelerating, but the speed is less than 200m/s.
1310 Drogue. The rocket has reached apogee and is heading
1311 back down, but is above the configured Main
1317 Main. The rocket is still descending, and is below
1323 Landed. The rocket is no longer moving.
1329 You can select a state to limit when the pyro channel
1330 may activate; note that the check is based on when the
1331 rocket transitions <emphasis>into</emphasis> the state, and so checking for
1332 “greater than Boost” means that the rocket is currently
1333 in boost or some later state.
1336 When a motor burns out, the rocket enters either Fast or
1337 Coast state (depending on how fast it is moving). If the
1338 computer detects upwards acceleration again, it will
1339 move back to Boost state.
1349 <title>AltosUI</title>
1351 The AltosUI program provides a graphical user interface for
1352 interacting with the Altus Metrum product family. AltosUI can
1353 monitor telemetry data, configure devices and many other
1354 tasks. The primary interface window provides a selection of
1355 buttons, one for each major activity in the system. This manual
1356 is split into chapters, each of which documents one of the tasks
1357 provided from the top-level toolbar.
1360 <title>Monitor Flight</title>
1361 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
1363 Selecting this item brings up a dialog box listing all of the
1364 connected TeleDongle devices. When you choose one of these,
1365 AltosUI will create a window to display telemetry data as
1366 received by the selected TeleDongle device.
1369 All telemetry data received are automatically recorded in
1370 suitable log files. The name of the files includes the current
1371 date and rocket serial and flight numbers.
1374 The radio frequency being monitored by the TeleDongle device is
1375 displayed at the top of the window. You can configure the
1376 frequency by clicking on the frequency box and selecting the desired
1377 frequency. AltosUI remembers the last frequency selected for each
1378 TeleDongle and selects that automatically the next time you use
1382 Below the TeleDongle frequency selector, the window contains a few
1383 significant pieces of information about the altimeter providing
1384 the telemetry data stream:
1388 <para>The configured call-sign</para>
1391 <para>The device serial number</para>
1394 <para>The flight number. Each altimeter remembers how many
1400 The rocket flight state. Each flight passes through several
1401 states including Pad, Boost, Fast, Coast, Drogue, Main and
1407 The Received Signal Strength Indicator value. This lets
1408 you know how strong a signal TeleDongle is receiving. The
1409 radio inside TeleDongle operates down to about -99dBm;
1410 weaker signals may not be receivable. The packet link uses
1411 error detection and correction techniques which prevent
1412 incorrect data from being reported.
1417 The age of the displayed data, in seconds since the last
1418 successfully received telemetry packet. In normal operation
1419 this will stay in the low single digits. If the number starts
1420 counting up, then you are no longer receiving data over the radio
1421 link from the flight computer.
1426 Finally, the largest portion of the window contains a set of
1427 tabs, each of which contain some information about the rocket.
1428 They're arranged in 'flight order' so that as the flight
1429 progresses, the selected tab automatically switches to display
1430 data relevant to the current state of the flight. You can select
1431 other tabs at any time. The final 'table' tab displays all of
1432 the raw telemetry values in one place in a spreadsheet-like format.
1435 <title>Launch Pad</title>
1437 The 'Launch Pad' tab shows information used to decide when the
1438 rocket is ready for flight. The first elements include red/green
1439 indicators, if any of these is red, you'll want to evaluate
1440 whether the rocket is ready to launch:
1443 <term>Battery Voltage</term>
1446 This indicates whether the Li-Po battery
1447 powering the TeleMetrum has sufficient charge to last for
1448 the duration of the flight. A value of more than
1449 3.8V is required for a 'GO' status.
1454 <term>Apogee Igniter Voltage</term>
1457 This indicates whether the apogee
1458 igniter has continuity. If the igniter has a low
1459 resistance, then the voltage measured here will be close
1460 to the Li-Po battery voltage. A value greater than 3.2V is
1461 required for a 'GO' status.
1466 <term>Main Igniter Voltage</term>
1469 This indicates whether the main
1470 igniter has continuity. If the igniter has a low
1471 resistance, then the voltage measured here will be close
1472 to the Li-Po battery voltage. A value greater than 3.2V is
1473 required for a 'GO' status.
1478 <term>On-board Data Logging</term>
1481 This indicates whether there is
1482 space remaining on-board to store flight data for the
1483 upcoming flight. If you've downloaded data, but failed
1484 to erase flights, there may not be any space
1485 left. TeleMetrum can store multiple flights, depending
1486 on the configured maximum flight log size. TeleMini
1487 stores only a single flight, so it will need to be
1488 downloaded and erased after each flight to capture
1489 data. This only affects on-board flight logging; the
1490 altimeter will still transmit telemetry and fire
1491 ejection charges at the proper times.
1496 <term>GPS Locked</term>
1499 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
1500 currently able to compute position information. GPS requires
1501 at least 4 satellites to compute an accurate position.
1506 <term>GPS Ready</term>
1509 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
1510 10 consecutive positions without losing lock. This ensures
1511 that the GPS receiver has reliable reception from the
1519 The Launchpad tab also shows the computed launch pad position
1520 and altitude, averaging many reported positions to improve the
1521 accuracy of the fix.
1525 <title>Ascent</title>
1527 This tab is shown during Boost, Fast and Coast
1528 phases. The information displayed here helps monitor the
1529 rocket as it heads towards apogee.
1532 The height, speed and acceleration are shown along with the
1533 maximum values for each of them. This allows you to quickly
1534 answer the most commonly asked questions you'll hear during
1538 The current latitude and longitude reported by the TeleMetrum GPS are
1539 also shown. Note that under high acceleration, these values
1540 may not get updated as the GPS receiver loses position
1541 fix. Once the rocket starts coasting, the receiver should
1542 start reporting position again.
1545 Finally, the current igniter voltages are reported as in the
1546 Launch Pad tab. This can help diagnose deployment failures
1547 caused by wiring which comes loose under high acceleration.
1551 <title>Descent</title>
1553 Once the rocket has reached apogee and (we hope) activated the
1554 apogee charge, attention switches to tracking the rocket on
1555 the way back to the ground, and for dual-deploy flights,
1556 waiting for the main charge to fire.
1559 To monitor whether the apogee charge operated correctly, the
1560 current descent rate is reported along with the current
1561 height. Good descent rates vary based on the choice of recovery
1562 components, but generally range from 15-30m/s on drogue and should
1563 be below 10m/s when under the main parachute in a dual-deploy flight.
1566 For TeleMetrum altimeters, you can locate the rocket in the
1567 sky using the elevation and bearing information to figure
1568 out where to look. Elevation is in degrees above the
1569 horizon. Bearing is reported in degrees relative to true
1570 north. Range can help figure out how big the rocket will
1571 appear. Ground Distance shows how far it is to a point
1572 directly under the rocket and can help figure out where the
1573 rocket is likely to land. Note that all of these values are
1574 relative to the pad location. If the elevation is near 90°,
1575 the rocket is over the pad, not over you.
1578 Finally, the igniter voltages are reported in this tab as
1579 well, both to monitor the main charge as well as to see what
1580 the status of the apogee charge is. Note that some commercial
1581 e-matches are designed to retain continuity even after being
1582 fired, and will continue to show as green or return from red to
1587 <title>Landed</title>
1589 Once the rocket is on the ground, attention switches to
1590 recovery. While the radio signal is often lost once the
1591 rocket is on the ground, the last reported GPS position is
1592 generally within a short distance of the actual landing location.
1595 The last reported GPS position is reported both by
1596 latitude and longitude as well as a bearing and distance from
1597 the launch pad. The distance should give you a good idea of
1598 whether to walk or hitch a ride. Take the reported
1599 latitude and longitude and enter them into your hand-held GPS
1600 unit and have that compute a track to the landing location.
1603 Both TeleMini and TeleMetrum will continue to transmit RDF
1604 tones after landing, allowing you to locate the rocket by
1605 following the radio signal if necessary. You may need to get
1606 away from the clutter of the flight line, or even get up on
1607 a hill (or your neighbor's RV roof) to receive the RDF signal.
1610 The maximum height, speed and acceleration reported
1611 during the flight are displayed for your admiring observers.
1612 The accuracy of these immediate values depends on the quality
1613 of your radio link and how many packets were received.
1614 Recovering the on-board data after flight will likely yield
1615 more precise results.
1618 To get more detailed information about the flight, you can
1619 click on the 'Graph Flight' button which will bring up a
1620 graph window for the current flight.
1624 <title>Site Map</title>
1626 When the TeleMetrum has a GPS fix, the Site Map tab will map
1627 the rocket's position to make it easier for you to locate the
1628 rocket, both while it is in the air, and when it has landed. The
1629 rocket's state is indicated by color: white for pad, red for
1630 boost, pink for fast, yellow for coast, light blue for drogue,
1631 dark blue for main, and black for landed.
1634 The map's scale is approximately 3m (10ft) per pixel. The map
1635 can be dragged using the left mouse button. The map will attempt
1636 to keep the rocket roughly centered while data is being received.
1639 Images are fetched automatically via the Google Maps Static API,
1640 and cached on disk for reuse. If map images cannot be downloaded,
1641 the rocket's path will be traced on a dark gray background
1645 You can pre-load images for your favorite launch sites
1646 before you leave home; check out the 'Preload Maps' section below.
1651 <title>Save Flight Data</title>
1653 The altimeter records flight data to its internal flash memory.
1654 TeleMetrum data is recorded at a much higher rate than the telemetry
1655 system can handle, and is not subject to radio drop-outs. As
1656 such, it provides a more complete and precise record of the
1657 flight. The 'Save Flight Data' button allows you to read the
1658 flash memory and write it to disk. As TeleMini has only a barometer, it
1659 records data at the same rate as the telemetry signal, but there will be
1660 no data lost due to telemetry drop-outs.
1663 Clicking on the 'Save Flight Data' button brings up a list of
1664 connected TeleMetrum and TeleDongle devices. If you select a
1665 TeleMetrum device, the flight data will be downloaded from that
1666 device directly. If you select a TeleDongle device, flight data
1667 will be downloaded from an altimeter over radio link via the
1668 specified TeleDongle. See the chapter on Controlling An Altimeter
1669 Over The Radio Link for more information.
1672 After the device has been selected, a dialog showing the
1673 flight data saved in the device will be shown allowing you to
1674 select which flights to download and which to delete. With
1675 version 0.9 or newer firmware, you must erase flights in order
1676 for the space they consume to be reused by another
1677 flight. This prevents accidentally losing flight data
1678 if you neglect to download data before flying again. Note that
1679 if there is no more space available in the device, then no
1680 data will be recorded during the next flight.
1683 The file name for each flight log is computed automatically
1684 from the recorded flight date, altimeter serial number and
1685 flight number information.
1689 <title>Replay Flight</title>
1691 Select this button and you are prompted to select a flight
1692 record file, either a .telem file recording telemetry data or a
1693 .eeprom file containing flight data saved from the altimeter
1697 Once a flight record is selected, the flight monitor interface
1698 is displayed and the flight is re-enacted in real time. Check
1699 the Monitor Flight chapter above to learn how this window operates.
1703 <title>Graph Data</title>
1705 Select this button and you are prompted to select a flight
1706 record file, either a .telem file recording telemetry data or a
1707 .eeprom file containing flight data saved from
1711 Once a flight record is selected, a window with multiple tabs is
1715 <term>Flight Graph</term>
1718 By default, the graph contains acceleration (blue),
1719 velocity (green) and altitude (red).
1724 <term>Configure Graph</term>
1727 This selects which graph elements to show, and, at the
1728 very bottom, lets you switch between metric and
1734 <term>Flight Statistics</term>
1737 Shows overall data computed from the flight.
1745 Shows a satellite image of the flight area overlaid
1746 with the path of the flight. The red concentric
1747 circles mark the launch pad, the black concentric
1748 circles mark the landing location.
1755 The graph can be zoomed into a particular area by clicking and
1756 dragging down and to the right. Once zoomed, the graph can be
1757 reset by clicking and dragging up and to the left. Holding down
1758 control and clicking and dragging allows the graph to be panned.
1759 The right mouse button causes a pop-up menu to be displayed, giving
1760 you the option save or print the plot.
1763 Note that telemetry files will generally produce poor graphs
1764 due to the lower sampling rate and missed telemetry packets.
1765 Use saved flight data in .eeprom files for graphing where possible.
1769 <title>Export Data</title>
1771 This tool takes the raw data files and makes them available for
1772 external analysis. When you select this button, you are prompted to
1774 data file (either .eeprom or .telem will do, remember that
1775 .eeprom files contain higher resolution and more continuous
1776 data). Next, a second dialog appears which is used to select
1777 where to write the resulting file. It has a selector to choose
1778 between CSV and KML file formats.
1781 <title>Comma Separated Value Format</title>
1783 This is a text file containing the data in a form suitable for
1784 import into a spreadsheet or other external data analysis
1785 tool. The first few lines of the file contain the version and
1786 configuration information from the altimeter, then
1787 there is a single header line which labels all of the
1788 fields. All of these lines start with a '#' character which
1789 many tools can be configured to skip over.
1792 The remaining lines of the file contain the data, with each
1793 field separated by a comma and at least one space. All of
1794 the sensor values are converted to standard units, with the
1795 barometric data reported in both pressure, altitude and
1796 height above pad units.
1800 <title>Keyhole Markup Language (for Google Earth)</title>
1802 This is the format used by Google Earth to provide an overlay
1803 within that application. With this, you can use Google Earth to
1804 see the whole flight path in 3D.
1809 <title>Configure Altimeter</title>
1811 Select this button and then select either an altimeter or
1812 TeleDongle Device from the list provided. Selecting a TeleDongle
1813 device will use the radio link to configure a remote altimeter.
1816 The first few lines of the dialog provide information about the
1817 connected device, including the product name,
1818 software version and hardware serial number. Below that are the
1819 individual configuration entries.
1822 At the bottom of the dialog, there are four buttons:
1829 This writes any changes to the
1830 configuration parameter block in flash memory. If you don't
1831 press this button, any changes you make will be lost.
1839 This resets the dialog to the most recently saved values,
1840 erasing any changes you have made.
1848 This reboots the device. Use this to
1849 switch from idle to pad mode by rebooting once the rocket is
1850 oriented for flight, or to confirm changes you think you saved
1859 This closes the dialog. Any unsaved changes will be
1866 The rest of the dialog contains the parameters to be configured.
1869 <title>Main Deploy Altitude</title>
1871 This sets the altitude (above the recorded pad altitude) at
1872 which the 'main' igniter will fire. The drop-down menu shows
1873 some common values, but you can edit the text directly and
1874 choose whatever you like. If the apogee charge fires below
1875 this altitude, then the main charge will fire two seconds
1876 after the apogee charge fires.
1880 <title>Apogee Delay</title>
1882 When flying redundant electronics, it's often important to
1883 ensure that multiple apogee charges don't fire at precisely
1884 the same time, as that can over pressurize the apogee deployment
1885 bay and cause a structural failure of the air-frame. The Apogee
1886 Delay parameter tells the flight computer to fire the apogee
1887 charge a certain number of seconds after apogee has been
1892 <title>Radio Frequency</title>
1894 This configures which of the frequencies to use for both
1895 telemetry and packet command mode. Note that if you set this
1896 value via packet command mode, the TeleDongle frequency will
1897 also be automatically reconfigured to match so that
1898 communication will continue afterwards.
1902 <title>RF Calibration</title>
1904 The radios in every Altus Metrum device are calibrated at the
1905 factory to ensure that they transmit and receive on the
1906 specified frequency. If you need to you can adjust the calibration
1907 by changing this value. Do not do this without understanding what
1908 the value means, read the appendix on calibration and/or the source
1909 code for more information. To change a TeleDongle's calibration,
1910 you must reprogram the unit completely.
1914 <title>Telemetry/RDF/APRS Enable</title>
1916 Enables the radio for transmission during flight. When
1917 disabled, the radio will not transmit anything during flight
1922 <title>APRS Interval</title>
1924 How often to transmit GPS information via APRS. This option
1925 is available on TeleMetrum v2 and TeleMega
1926 boards. TeleMetrum v1 boards cannot transmit APRS
1927 packets. Note that a single APRS packet takes nearly a full
1928 second to transmit, so enabling this option will prevent
1929 sending any other telemetry during that time.
1933 <title>Callsign</title>
1935 This sets the call sign included in each telemetry packet. Set this
1936 as needed to conform to your local radio regulations.
1940 <title>Maximum Flight Log Size</title>
1942 This sets the space (in kilobytes) allocated for each flight
1943 log. The available space will be divided into chunks of this
1944 size. A smaller value will allow more flights to be stored,
1945 a larger value will record data from longer flights.
1949 <title>Ignite Mode</title>
1951 TeleMetrum and TeleMini provide two igniter channels as they
1952 were originally designed as dual-deploy flight
1953 computers. This configuration parameter allows the two
1954 channels to be used in different configurations.
1958 <term>Dual Deploy</term>
1961 This is the usual mode of operation; the
1962 'apogee' channel is fired at apogee and the 'main'
1963 channel at the height above ground specified by the
1964 'Main Deploy Altitude' during descent.
1969 <term>Redundant Apogee</term>
1972 This fires both channels at
1973 apogee, the 'apogee' channel first followed after a two second
1974 delay by the 'main' channel.
1979 <term>Redundant Main</term>
1982 This fires both channels at the
1983 height above ground specified by the Main Deploy
1984 Altitude setting during descent. The 'apogee'
1985 channel is fired first, followed after a two second
1986 delay by the 'main' channel.
1993 <title>Pad Orientation</title>
1995 Because it includes an accelerometer, TeleMetrum and
1996 TeleMega are sensitive to the orientation of the board. By
1997 default, it expects the antenna end to point forward. This
1998 parameter allows that default to be changed, permitting the
1999 board to be mounted with the antenna pointing aft instead.
2003 <term>Antenna Up</term>
2006 In this mode, the antenna end of the
2007 TeleMetrum board must point forward, in line with the
2008 expected flight path.
2013 <term>Antenna Down</term>
2016 In this mode, the antenna end of the
2017 TeleMetrum board must point aft, in line with the
2018 expected flight path.
2025 <title>Configure Pyro Channels</title>
2027 This opens a separate window to configure the additional
2028 pyro channels available on TeleMega. One column is
2029 presented for each channel. Each row represents a single
2030 parameter, if enabled the parameter must meet the specified
2031 test for the pyro channel to be fired. See the Pyro Channels
2032 section in the System Operation chapter above for a
2033 description of these parameters.
2036 Select conditions and set the related value; the pyro
2037 channel will be activated when <emphasis>all</emphasis> of the
2038 conditions are met. Each pyro channel has a separate set of
2039 configuration values, so you can use different values for
2040 the same condition with different channels.
2043 Once you have selected the appropriate configuration for all
2044 of the necessary pyro channels, you can save the pyro
2045 configuration along with the rest of the flight computer
2046 configuration by pressing the 'Save' button in the main
2047 Configure Flight Computer window.
2052 <title>Configure AltosUI</title>
2054 This button presents a dialog so that you can configure the AltosUI global settings.
2057 <title>Voice Settings</title>
2059 AltosUI provides voice announcements during flight so that you
2060 can keep your eyes on the sky and still get information about
2061 the current flight status. However, sometimes you don't want
2066 <para>Enable—turns all voice announcements on and off</para>
2070 Test Voice—Plays a short message allowing you to verify
2071 that the audio system is working and the volume settings
2078 <title>Log Directory</title>
2080 AltosUI logs all telemetry data and saves all TeleMetrum flash
2081 data to this directory. This directory is also used as the
2082 staring point when selecting data files for display or export.
2085 Click on the directory name to bring up a directory choosing
2086 dialog, select a new directory and click 'Select Directory' to
2087 change where AltosUI reads and writes data files.
2091 <title>Callsign</title>
2093 This value is transmitted in each command packet sent from
2094 TeleDongle and received from an altimeter. It is not used in
2095 telemetry mode, as the callsign configured in the altimeter board
2096 is included in all telemetry packets. Configure this
2097 with the AltosUI operators call sign as needed to comply with
2098 your local radio regulations.
2101 Note that to successfully command a flight computer over the radio
2102 (to configure the altimeter, monitor idle, or fire pyro charges),
2103 the callsign configured here must exactly match the callsign
2104 configured in the flight computer. This matching is case
2109 <title>Imperial Units</title>
2111 This switches between metric units (meters) and imperial
2112 units (feet and miles). This affects the display of values
2113 use during flight monitoring, configuration, data graphing
2114 and all of the voice announcements. It does not change the
2115 units used when exporting to CSV files, those are always
2116 produced in metric units.
2120 <title>Font Size</title>
2122 Selects the set of fonts used in the flight monitor
2123 window. Choose between the small, medium and large sets.
2127 <title>Serial Debug</title>
2129 This causes all communication with a connected device to be
2130 dumped to the console from which AltosUI was started. If
2131 you've started it from an icon or menu entry, the output
2132 will simply be discarded. This mode can be useful to debug
2133 various serial communication issues.
2137 <title>Manage Frequencies</title>
2139 This brings up a dialog where you can configure the set of
2140 frequencies shown in the various frequency menus. You can
2141 add as many as you like, or even reconfigure the default
2142 set. Changing this list does not affect the frequency
2143 settings of any devices, it only changes the set of
2144 frequencies shown in the menus.
2149 <title>Configure Groundstation</title>
2151 Select this button and then select a TeleDongle Device from the list provided.
2154 The first few lines of the dialog provide information about the
2155 connected device, including the product name,
2156 software version and hardware serial number. Below that are the
2157 individual configuration entries.
2160 Note that the TeleDongle itself doesn't save any configuration
2161 data, the settings here are recorded on the local machine in
2162 the Java preferences database. Moving the TeleDongle to
2163 another machine, or using a different user account on the same
2164 machine will cause settings made here to have no effect.
2167 At the bottom of the dialog, there are three buttons:
2174 This writes any changes to the
2175 local Java preferences file. If you don't
2176 press this button, any changes you make will be lost.
2184 This resets the dialog to the most recently saved values,
2185 erasing any changes you have made.
2193 This closes the dialog. Any unsaved changes will be
2200 The rest of the dialog contains the parameters to be configured.
2203 <title>Frequency</title>
2205 This configures the frequency to use for both telemetry and
2206 packet command mode. Set this before starting any operation
2207 involving packet command mode so that it will use the right
2208 frequency. Telemetry monitoring mode also provides a menu to
2209 change the frequency, and that menu also sets the same Java
2210 preference value used here.
2214 <title>Radio Calibration</title>
2216 The radios in every Altus Metrum device are calibrated at the
2217 factory to ensure that they transmit and receive on the
2218 specified frequency. To change a TeleDongle's calibration,
2219 you must reprogram the unit completely, so this entry simply
2220 shows the current value and doesn't allow any changes.
2225 <title>Flash Image</title>
2227 This reprograms Altus Metrum device with new
2228 firmware. TeleMetrum v1.x, TeleDongle, TeleMini and TeleBT are
2229 all reprogrammed by using another similar unit as a
2230 programming dongle (pair programming). TeleMega, TeleMetrum v2
2231 and EasyMini are all programmed directly over their USB ports
2232 (self programming). Please read the directions for flashing
2233 devices in the Updating Device Firmware chapter below.
2236 For “self programming”, connect USB to the device to be
2237 programmed and push the 'Flash Image' button. That will
2238 present a dialog box listing all of the connected
2239 devices. Carefully select the device to be programmed.
2242 For “pair programming”, once you have the programmer and
2243 target devices connected, push the 'Flash Image' button. That
2244 will present a dialog box listing all of the connected
2245 devices. Carefully select the programmer device, not the
2246 device to be programmed.
2249 Next, select the image to flash to the device. These are named
2250 with the product name and firmware version. The file selector
2251 will start in the directory containing the firmware included
2252 with the AltosUI package. Navigate to the directory containing
2253 the desired firmware if it isn't there.
2256 Next, a small dialog containing the device serial number and
2257 RF calibration values should appear. If these values are
2258 incorrect (possibly due to a corrupted image in the device),
2259 enter the correct values here.
2262 Finally, a dialog containing a progress bar will follow the
2263 programming process.
2266 When programming is complete, the target device will
2267 reboot. Note that if a pair programmed target device is
2268 connected via USB, you will have to unplug it and then plug it
2269 back in for the USB connection to reset so that you can
2270 communicate with the device again.
2274 <title>Fire Igniter</title>
2276 This activates the igniter circuits in TeleMetrum to help test
2277 recovery systems deployment. Because this command can operate
2278 over the Packet Command Link, you can prepare the rocket as
2279 for flight and then test the recovery system without needing
2280 to snake wires inside the air-frame.
2283 Selecting the 'Fire Igniter' button brings up the usual device
2284 selection dialog. Pick the desired TeleDongle or TeleMetrum
2285 device. This brings up another window which shows the current
2286 continuity test status for both apogee and main charges.
2289 Next, select the desired igniter to fire. This will enable the
2293 Select the 'Arm' button. This enables the 'Fire' button. The
2294 word 'Arm' is replaced by a countdown timer indicating that
2295 you have 10 seconds to press the 'Fire' button or the system
2296 will deactivate, at which point you start over again at
2297 selecting the desired igniter.
2301 <title>Scan Channels</title>
2303 This listens for telemetry packets on all of the configured
2304 frequencies, displaying information about each device it
2305 receives a packet from. You can select which of the three
2306 telemetry formats should be tried; by default, it only listens
2307 for the standard telemetry packets used in v1.0 and later
2312 <title>Load Maps</title>
2314 Before heading out to a new launch site, you can use this to
2315 load satellite images in case you don't have internet
2316 connectivity at the site. This loads a fairly large area
2317 around the launch site, which should cover any flight you're likely to make.
2320 There's a drop-down menu of launch sites we know about; if
2321 your favorites aren't there, please let us know the lat/lon
2322 and name of the site. The contents of this list are actually
2323 downloaded at run-time, so as new sites are sent in, they'll
2324 get automatically added to this list.
2327 If the launch site isn't in the list, you can manually enter the lat/lon values
2330 Clicking the 'Load Map' button will fetch images from Google
2331 Maps; note that Google limits how many images you can fetch at
2332 once, so if you load more than one launch site, you may get
2333 some gray areas in the map which indicate that Google is tired
2334 of sending data to you. Try again later.
2338 <title>Monitor Idle</title>
2340 This brings up a dialog similar to the Monitor Flight UI,
2341 except it works with the altimeter in “idle” mode by sending
2342 query commands to discover the current state rather than
2343 listening for telemetry packets. Because this uses command
2344 mode, it needs to have the TeleDongle and flight computer
2345 callsigns match exactly. If you can receive telemetry, but
2346 cannot manage to run Monitor Idle, then it's very likely that
2347 your callsigns are different in some way.
2352 <title>AltosDroid</title>
2354 AltosDroid provides the same flight monitoring capabilities as
2355 AltosUI, but runs on Android devices and is designed to connect
2356 to a TeleBT receiver over Bluetooth™. Altos Droid monitors
2357 telemetry data, logging it to internal storage in the Android
2358 device, and presents that data in a UI the same way the 'Monitor
2359 Flight' window does in AltosUI.
2362 This manual will explain how to configure AltosDroid, connect
2363 to TeleBT, operate the flight monitoring interface and describe
2364 what the displayed data means.
2367 <title>Installing AltosDroid</title>
2369 AltosDroid is included in the Google Play store. To install
2370 it on your Android device, open open the Google Play Store
2371 application and search for “altosdroid”. Make sure you don't
2372 have a space between “altos” and “droid” or you probably won't
2373 find what you want. That should bring you to the right page
2374 from which you can download and install the application.
2378 <title>Connecting to TeleBT</title>
2380 Press the Android 'Menu' button or soft-key to see the
2381 configuration options available. Select the 'Connect a device'
2382 option and then the 'Scan for devices' entry at the bottom to
2383 look for your TeleBT device. Select your device, and when it
2384 asks for the code, enter '1234'.
2387 Subsequent connections will not require you to enter that
2388 code, and your 'paired' device will appear in the list without
2393 <title>Configuring AltosDroid</title>
2395 The only configuration option available for AltosDroid is
2396 which frequency to listen on. Press the Android 'Menu' button
2397 or soft-key and pick the 'Select radio frequency' entry. That
2398 brings up a menu of pre-set radio frequencies; pick the one
2399 which matches your altimeter.
2403 <title>Altos Droid Flight Monitoring</title>
2405 Altos Droid is designed to mimic the AltosUI flight monitoring
2406 display, providing separate tabs for each stage of your rocket
2407 flight along with a tab containing a map of the local area
2408 with icons marking the current location of the altimeter and
2414 The 'Launch Pad' tab shows information used to decide when the
2415 rocket is ready for flight. The first elements include red/green
2416 indicators, if any of these is red, you'll want to evaluate
2417 whether the rocket is ready to launch:
2420 <term>Battery Voltage</term>
2423 This indicates whether the Li-Po battery
2424 powering the TeleMetrum has sufficient charge to last for
2425 the duration of the flight. A value of more than
2426 3.8V is required for a 'GO' status.
2431 <term>Apogee Igniter Voltage</term>
2434 This indicates whether the apogee
2435 igniter has continuity. If the igniter has a low
2436 resistance, then the voltage measured here will be close
2437 to the Li-Po battery voltage. A value greater than 3.2V is
2438 required for a 'GO' status.
2443 <term>Main Igniter Voltage</term>
2446 This indicates whether the main
2447 igniter has continuity. If the igniter has a low
2448 resistance, then the voltage measured here will be close
2449 to the Li-Po battery voltage. A value greater than 3.2V is
2450 required for a 'GO' status.
2455 <term>On-board Data Logging</term>
2458 This indicates whether there is
2459 space remaining on-board to store flight data for the
2460 upcoming flight. If you've downloaded data, but failed
2461 to erase flights, there may not be any space
2462 left. TeleMetrum can store multiple flights, depending
2463 on the configured maximum flight log size. TeleMini
2464 stores only a single flight, so it will need to be
2465 downloaded and erased after each flight to capture
2466 data. This only affects on-board flight logging; the
2467 altimeter will still transmit telemetry and fire
2468 ejection charges at the proper times.
2473 <term>GPS Locked</term>
2476 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
2477 currently able to compute position information. GPS requires
2478 at least 4 satellites to compute an accurate position.
2483 <term>GPS Ready</term>
2486 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
2487 10 consecutive positions without losing lock. This ensures
2488 that the GPS receiver has reliable reception from the
2496 The Launchpad tab also shows the computed launch pad position
2497 and altitude, averaging many reported positions to improve the
2498 accuracy of the fix.
2503 <title>Downloading Flight Logs</title>
2505 Altos Droid always saves every bit of telemetry data it
2506 receives. To download that to a computer for use with AltosUI,
2507 simply remove the SD card from your Android device, or connect
2508 your device to your computer's USB port and browse the files
2509 on that device. You will find '.telem' files in the TeleMetrum
2510 directory that will work with AltosUI directly.
2515 <title>Using Altus Metrum Products</title>
2517 <title>Being Legal</title>
2519 First off, in the US, you need an <ulink url="http://www.altusmetrum.org/Radio/">amateur radio license</ulink> or
2520 other authorization to legally operate the radio transmitters that are part
2525 <title>In the Rocket</title>
2527 In the rocket itself, you just need a <ulink url="http://www.altusmetrum.org/TeleMetrum/">TeleMetrum</ulink> or
2528 <ulink url="http://www.altusmetrum.org/TeleMini/">TeleMini</ulink> board and
2529 a single-cell, 3.7 volt nominal Li-Po rechargeable battery. An
2530 850mAh battery weighs less than a 9V alkaline battery, and will
2531 run a TeleMetrum for hours.
2532 A 110mAh battery weighs less than a triple A battery and will run a TeleMetrum for
2533 a few hours, or a TeleMini for much (much) longer.
2536 By default, we ship the altimeters with a simple wire antenna. If your
2537 electronics bay or the air-frame it resides within is made of carbon fiber,
2538 which is opaque to RF signals, you may choose to have an SMA connector
2539 installed so that you can run a coaxial cable to an antenna mounted
2540 elsewhere in the rocket.
2544 <title>On the Ground</title>
2546 To receive the data stream from the rocket, you need an antenna and short
2547 feed-line connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. If possible, use an SMA to BNC
2548 adapter instead of feedline between the antenna feedpoint and
2549 TeleDongle, as this will give you the best performance. The
2550 TeleDongle in turn plugs directly into the USB port on a notebook
2551 computer. Because TeleDongle looks like a simple serial port, your computer
2552 does not require special device drivers... just plug it in.
2555 The GUI tool, AltosUI, is written in Java and runs across
2556 Linux, Mac OS and Windows. There's also a suite of C tools
2557 for Linux which can perform most of the same tasks.
2560 After the flight, you can use the radio link to extract the more detailed data
2561 logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
2562 TeleMetrum board directly. Pulling out the data without having to open up
2563 the rocket is pretty cool! A USB cable is also how you charge the Li-Po
2564 battery, so you'll want one of those anyway... the same cable used by lots
2565 of digital cameras and other modern electronic stuff will work fine.
2568 If your TeleMetrum-equipped rocket lands out of sight, you may enjoy having a hand-held GPS
2569 receiver, so that you can put in a way-point for the last reported rocket
2570 position before touch-down. This makes looking for your rocket a lot like
2571 Geo-Caching... just go to the way-point and look around starting from there.
2574 You may also enjoy having a ham radio “HT” that covers the 70cm band... you
2575 can use that with your antenna to direction-find the rocket on the ground
2576 the same way you can use a Walston or Beeline tracker. This can be handy
2577 if the rocket is hiding in sage brush or a tree, or if the last GPS position
2578 doesn't get you close enough because the rocket dropped into a canyon, or
2579 the wind is blowing it across a dry lake bed, or something like that... Keith
2580 currently uses a Yaesu VX-7R, Bdale has a Baofung UV-5R
2581 which isn't as nice, but was a whole lot cheaper.
2584 So, to recap, on the ground the hardware you'll need includes:
2585 <orderedlist inheritnum='inherit' numeration='arabic'>
2588 an antenna and feed-line or adapter
2603 optionally, a hand-held GPS receiver
2608 optionally, an HT or receiver covering 435 MHz
2614 The best hand-held commercial directional antennas we've found for radio
2615 direction finding rockets are from
2616 <ulink url="http://www.arrowantennas.com/" >
2619 The 440-3 and 440-5 are both good choices for finding a
2620 TeleMetrum- or TeleMini- equipped rocket when used with a suitable
2621 70cm HT. TeleDongle and an SMA to BNC adapter fit perfectly
2622 between the driven element and reflector of Arrow antennas.
2626 <title>Data Analysis</title>
2628 Our software makes it easy to log the data from each flight, both the
2629 telemetry received during the flight itself, and the more
2630 complete data log recorded in the flash memory on the altimeter
2631 board. Once this data is on your computer, our post-flight tools make it
2632 easy to quickly get to the numbers everyone wants, like apogee altitude,
2633 max acceleration, and max velocity. You can also generate and view a
2634 standard set of plots showing the altitude, acceleration, and
2635 velocity of the rocket during flight. And you can even export a TeleMetrum data file
2636 usable with Google Maps and Google Earth for visualizing the flight path
2637 in two or three dimensions!
2640 Our ultimate goal is to emit a set of files for each flight that can be
2641 published as a web page per flight, or just viewed on your local disk with
2646 <title>Future Plans</title>
2648 In the future, we intend to offer “companion boards” for the rocket
2649 that will plug in to TeleMetrum to collect additional data, provide
2650 more pyro channels, and so forth.
2653 Also under design is a new flight computer with more sensors, more
2654 pyro channels, and a more powerful radio system designed for use
2655 in multi-stage, complex, and extreme altitude projects.
2658 We are also working on alternatives to TeleDongle. One is a
2659 a stand-alone, hand-held ground terminal that will allow monitoring
2660 the rocket's status, collecting data during flight, and logging data
2661 after flight without the need for a notebook computer on the
2662 flight line. Particularly since it is so difficult to read most
2663 notebook screens in direct sunlight, we think this will be a great
2664 thing to have. We are also working on a TeleDongle variant with
2665 Bluetooth that will work with Android phones and tablets.
2668 Because all of our work is open, both the hardware designs and the
2669 software, if you have some great idea for an addition to the current
2670 Altus Metrum family, feel free to dive in and help! Or let us know
2671 what you'd like to see that we aren't already working on, and maybe
2672 we'll get excited about it too...
2676 <ulink url="http://altusmetrum.org/">web site</ulink> for more news
2677 and information as our family of products evolves!
2682 <title>Altimeter Installation Recommendations</title>
2684 Building high-power rockets that fly safely is hard enough. Mix
2685 in some sophisticated electronics and a bunch of radio energy
2686 and oftentimes you find few perfect solutions. This chapter
2687 contains some suggestions about how to install Altus Metrum
2688 products into the rocket air-frame, including how to safely and
2689 reliably mix a variety of electronics into the same air-frame.
2692 <title>Mounting the Altimeter</title>
2694 The first consideration is to ensure that the altimeter is
2695 securely fastened to the air-frame. For TeleMetrum, we use
2696 nylon standoffs and nylon screws; they're good to at least 50G
2697 and cannot cause any electrical issues on the board. For
2698 TeleMini, we usually cut small pieces of 1/16 inch balsa to fit
2699 under the screw holes, and then take 2x56 nylon screws and
2700 screw them through the TeleMini mounting holes, through the
2701 balsa and into the underlying material.
2703 <orderedlist inheritnum='inherit' numeration='arabic'>
2706 Make sure TeleMetrum is aligned precisely along the axis of
2707 acceleration so that the accelerometer can accurately
2708 capture data during the flight.
2713 Watch for any metal touching components on the
2714 board. Shorting out connections on the bottom of the board
2715 can cause the altimeter to fail during flight.
2721 <title>Dealing with the Antenna</title>
2723 The antenna supplied is just a piece of solid, insulated,
2724 wire. If it gets damaged or broken, it can be easily
2725 replaced. It should be kept straight and not cut; bending or
2726 cutting it will change the resonant frequency and/or
2727 impedance, making it a less efficient radiator and thus
2728 reducing the range of the telemetry signal.
2731 Keeping metal away from the antenna will provide better range
2732 and a more even radiation pattern. In most rockets, it's not
2733 entirely possible to isolate the antenna from metal
2734 components; there are often bolts, all-thread and wires from other
2735 electronics to contend with. Just be aware that the more stuff
2736 like this around the antenna, the lower the range.
2739 Make sure the antenna is not inside a tube made or covered
2740 with conducting material. Carbon fiber is the most common
2741 culprit here -- CF is a good conductor and will effectively
2742 shield the antenna, dramatically reducing signal strength and
2743 range. Metallic flake paint is another effective shielding
2744 material which is to be avoided around any antennas.
2747 If the ebay is large enough, it can be convenient to simply
2748 mount the altimeter at one end and stretch the antenna out
2749 inside. Taping the antenna to the sled can keep it straight
2750 under acceleration. If there are metal rods, keep the
2751 antenna as far away as possible.
2754 For a shorter ebay, it's quite practical to have the antenna
2755 run through a bulkhead and into an adjacent bay. Drill a small
2756 hole in the bulkhead, pass the antenna wire through it and
2757 then seal it up with glue or clay. We've also used acrylic
2758 tubing to create a cavity for the antenna wire. This works a
2759 bit better in that the antenna is known to stay straight and
2760 not get folded by recovery components in the bay. Angle the
2761 tubing towards the side wall of the rocket and it ends up
2762 consuming very little space.
2765 If you need to place the antenna at a distance from the
2766 altimeter, you can replace the antenna with an edge-mounted
2767 SMA connector, and then run 50Ω coax from the board to the
2768 antenna. Building a remote antenna is beyond the scope of this
2773 <title>Preserving GPS Reception</title>
2775 The GPS antenna and receiver in TeleMetrum are highly
2776 sensitive and normally have no trouble tracking enough
2777 satellites to provide accurate position information for
2778 recovering the rocket. However, there are many ways to
2779 attenuate the GPS signal.
2780 <orderedlist inheritnum='inherit' numeration='arabic'>
2783 Conductive tubing or coatings. Carbon fiber and metal
2784 tubing, or metallic paint will all dramatically attenuate the
2785 GPS signal. We've never heard of anyone successfully
2786 receiving GPS from inside these materials.
2791 Metal components near the GPS patch antenna. These will
2792 de-tune the patch antenna, changing the resonant frequency
2793 away from the L1 carrier and reduce the effectiveness of the
2794 antenna. You can place as much stuff as you like beneath the
2795 antenna as that's covered with a ground plane. But, keep
2796 wires and metal out from above the patch antenna.
2803 <title>Radio Frequency Interference</title>
2805 Any altimeter will generate RFI; the digital circuits use
2806 high-frequency clocks that spray radio interference across a
2807 wide band. Altus Metrum altimeters generate intentional radio
2808 signals as well, increasing the amount of RF energy around the board.
2811 Rocketry altimeters also use precise sensors measuring air
2812 pressure and acceleration. Tiny changes in voltage can cause
2813 these sensor readings to vary by a huge amount. When the
2814 sensors start mis-reporting data, the altimeter can either
2815 fire the igniters at the wrong time, or not fire them at all.
2818 Voltages are induced when radio frequency energy is
2819 transmitted from one circuit to another. Here are things that
2820 influence the induced voltage and current:
2825 Keep wires from different circuits apart. Moving circuits
2826 further apart will reduce RFI.
2831 Avoid parallel wires from different circuits. The longer two
2832 wires run parallel to one another, the larger the amount of
2833 transferred energy. Cross wires at right angles to reduce
2839 Twist wires from the same circuits. Two wires the same
2840 distance from the transmitter will get the same amount of
2841 induced energy which will then cancel out. Any time you have
2842 a wire pair running together, twist the pair together to
2843 even out distances and reduce RFI. For altimeters, this
2844 includes battery leads, switch hookups and igniter
2850 Avoid resonant lengths. Know what frequencies are present
2851 in the environment and avoid having wire lengths near a
2852 natural resonant length. Altusmetrum products transmit on the
2853 70cm amateur band, so you should avoid lengths that are a
2854 simple ratio of that length; essentially any multiple of ¼
2855 of the wavelength (17.5cm).
2861 <title>The Barometric Sensor</title>
2863 Altusmetrum altimeters measure altitude with a barometric
2864 sensor, essentially measuring the amount of air above the
2865 rocket to figure out how high it is. A large number of
2866 measurements are taken as the altimeter initializes itself to
2867 figure out the pad altitude. Subsequent measurements are then
2868 used to compute the height above the pad.
2871 To accurately measure atmospheric pressure, the ebay
2872 containing the altimeter must be vented outside the
2873 air-frame. The vent must be placed in a region of linear
2874 airflow, have smooth edges, and away from areas of increasing or
2875 decreasing pressure.
2878 The barometric sensor in the altimeter is quite sensitive to
2879 chemical damage from the products of APCP or BP combustion, so
2880 make sure the ebay is carefully sealed from any compartment
2881 which contains ejection charges or motors.
2885 <title>Ground Testing</title>
2887 The most important aspect of any installation is careful
2888 ground testing. Bringing an air-frame up to the LCO table which
2889 hasn't been ground tested can lead to delays or ejection
2890 charges firing on the pad, or, even worse, a recovery system
2894 Do a 'full systems' test that includes wiring up all igniters
2895 without any BP and turning on all of the electronics in flight
2896 mode. This will catch any mistakes in wiring and any residual
2897 RFI issues that might accidentally fire igniters at the wrong
2898 time. Let the air-frame sit for several minutes, checking for
2899 adequate telemetry signal strength and GPS lock. If any igniters
2900 fire unexpectedly, find and resolve the issue before loading any
2904 Ground test the ejection charges. Prepare the rocket for
2905 flight, loading ejection charges and igniters. Completely
2906 assemble the air-frame and then use the 'Fire Igniters'
2907 interface through a TeleDongle to command each charge to
2908 fire. Make sure the charge is sufficient to robustly separate
2909 the air-frame and deploy the recovery system.
2914 <title>Updating Device Firmware</title>
2916 TeleMega, TeleMetrum v2 and EasyMini are all programmed directly
2917 over their USB connectors (self programming). TeleMetrum v1, TeleMini and
2918 TeleDongle are all programmed by using another device as a
2919 programmer (pair programming). It's important to recognize which
2920 kind of devices you have before trying to reprogram them.
2923 You may wish to begin by ensuring you have current firmware images.
2924 These are distributed as part of the AltOS software bundle that
2925 also includes the AltosUI ground station program. Newer ground
2926 station versions typically work fine with older firmware versions,
2927 so you don't need to update your devices just to try out new
2928 software features. You can always download the most recent
2929 version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
2932 We recommend updating the altimeter first, before updating TeleDongle.
2935 Self-programmable devices (TeleMega, TeleMetrum v2 and EasyMini)
2936 are reprogrammed by connecting them to your computer over USB
2940 Updating TeleMega, TeleMetrum v2 or EasyMini Firmware
2942 <orderedlist inheritnum='inherit' numeration='arabic'>
2945 Attach a battery and power switch to the target
2946 device. Power up the device.
2951 Using a Micro USB cable, connect the target device to your
2952 computer's USB socket.
2957 Run AltosUI, and select 'Flash Image' from the File menu.
2962 Select the target device in the Device Selection dialog.
2967 Select the image you want to flash to the device, which
2968 should have a name in the form
2969 <product>-v<product-version>-<software-version>.ihx, such
2970 as TeleMega-v1.0-1.3.0.ihx.
2975 Make sure the configuration parameters are reasonable
2976 looking. If the serial number and/or RF configuration
2977 values aren't right, you'll need to change them.
2982 Hit the 'OK' button and the software should proceed to flash
2983 the device with new firmware, showing a progress bar.
2988 Verify that the device is working by using the 'Configure
2989 Altimeter' item to check over the configuration.
2994 <title>Recovering From Self-Flashing Failure</title>
2996 If the firmware loading fails, it can leave the device
2997 unable to boot. Not to worry, you can force the device to
2998 start the boot loader instead, which will let you try to
2999 flash the device again.
3002 On each device, connecting two pins from one of the exposed
3003 connectors will force the boot loader to start, even if the
3004 regular operating system has been corrupted in some way.
3008 <term>TeleMega</term>
3011 Connect pin 6 and pin 1 of the companion connector. Pin 1
3012 can be identified by the square pad around it, and then
3013 the pins could sequentially across the board. Be very
3014 careful to <emphasis>not</emphasis> short pin 8 to
3015 anything as that is connected directly to the battery. Pin
3016 7 carries 3.3V and the board will crash if that is
3017 connected to pin 1, but shouldn't damage the board.
3022 <term>TeleMetrum v2</term>
3025 Connect pin 6 and pin 1 of the companion connector. Pin 1
3026 can be identified by the square pad around it, and then
3027 the pins could sequentially across the board. Be very
3028 careful to <emphasis>not</emphasis> short pin 8 to
3029 anything as that is connected directly to the battery. Pin
3030 7 carries 3.3V and the board will crash if that is
3031 connected to pin 1, but shouldn't damage the board.
3036 <term>EasyMini</term>
3039 Connect pin 6 and pin 1 of the debug connector, which is
3040 the six holes next to the beeper. Pin 1 can be identified
3041 by the square pad around it, and then the pins could
3042 sequentially across the board, making Pin 6 the one on the
3043 other end of the row.
3051 <title>Pair Programming</title>
3053 The big concept to understand is that you have to use a
3054 TeleMega, TeleMetrum or TeleDongle as a programmer to update a
3055 pair programmed device. Due to limited memory resources in the
3056 cc1111, we don't support programming directly over USB for these
3061 <title>Updating TeleMetrum v1.x Firmware</title>
3062 <orderedlist inheritnum='inherit' numeration='arabic'>
3065 Find the 'programming cable' that you got as part of the starter
3066 kit, that has a red 8-pin MicroMaTch connector on one end and a
3067 red 4-pin MicroMaTch connector on the other end.
3072 Take the 2 screws out of the TeleDongle case to get access
3073 to the circuit board.
3078 Plug the 8-pin end of the programming cable to the
3079 matching connector on the TeleDongle, and the 4-pin end to the
3080 matching connector on the TeleMetrum.
3081 Note that each MicroMaTch connector has an alignment pin that
3082 goes through a hole in the PC board when you have the cable
3088 Attach a battery to the TeleMetrum board.
3093 Plug the TeleDongle into your computer's USB port, and power
3099 Run AltosUI, and select 'Flash Image' from the File menu.
3104 Pick the TeleDongle device from the list, identifying it as the
3110 Select the image you want put on the TeleMetrum, which should have a
3111 name in the form telemetrum-v1.2-1.0.0.ihx. It should be visible
3112 in the default directory, if not you may have to poke around
3113 your system to find it.
3118 Make sure the configuration parameters are reasonable
3119 looking. If the serial number and/or RF configuration
3120 values aren't right, you'll need to change them.
3125 Hit the 'OK' button and the software should proceed to flash
3126 the TeleMetrum with new firmware, showing a progress bar.
3131 Confirm that the TeleMetrum board seems to have updated OK, which you
3132 can do by plugging in to it over USB and using a terminal program
3133 to connect to the board and issue the 'v' command to check
3139 If something goes wrong, give it another try.
3145 <title>Updating TeleMini Firmware</title>
3146 <orderedlist inheritnum='inherit' numeration='arabic'>
3149 You'll need a special 'programming cable' to reprogram the
3150 TeleMini. It's available on the Altus Metrum web store, or
3151 you can make your own using an 8-pin MicroMaTch connector on
3152 one end and a set of four pins on the other.
3157 Take the 2 screws out of the TeleDongle case to get access
3158 to the circuit board.
3163 Plug the 8-pin end of the programming cable to the matching
3164 connector on the TeleDongle, and the 4-pins into the holes
3165 in the TeleMini circuit board. Note that the MicroMaTch
3166 connector has an alignment pin that goes through a hole in
3167 the PC board when you have the cable oriented correctly, and
3168 that pin 1 on the TeleMini board is marked with a square pad
3169 while the other pins have round pads.
3174 Attach a battery to the TeleMini board.
3179 Plug the TeleDongle into your computer's USB port, and power
3185 Run AltosUI, and select 'Flash Image' from the File menu.
3190 Pick the TeleDongle device from the list, identifying it as the
3196 Select the image you want put on the TeleMini, which should have a
3197 name in the form telemini-v1.0-1.0.0.ihx. It should be visible
3198 in the default directory, if not you may have to poke around
3199 your system to find it.
3204 Make sure the configuration parameters are reasonable
3205 looking. If the serial number and/or RF configuration
3206 values aren't right, you'll need to change them.
3211 Hit the 'OK' button and the software should proceed to flash
3212 the TeleMini with new firmware, showing a progress bar.
3217 Confirm that the TeleMini board seems to have updated OK, which you
3218 can do by configuring it over the radio link through the TeleDongle, or
3219 letting it come up in “flight” mode and listening for telemetry.
3224 If something goes wrong, give it another try.
3230 <title>Updating TeleDongle Firmware</title>
3232 Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
3233 firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
3235 <orderedlist inheritnum='inherit' numeration='arabic'>
3238 Find the 'programming cable' that you got as part of the starter
3239 kit, that has a red 8-pin MicroMaTch connector on one end and a
3240 red 4-pin MicroMaTch connector on the other end.
3245 Find the USB cable that you got as part of the starter kit, and
3246 plug the “mini” end in to the mating connector on TeleMetrum or TeleDongle.
3251 Take the 2 screws out of the TeleDongle case to get access
3252 to the circuit board.
3257 Plug the 8-pin end of the programming cable to the
3258 matching connector on the programmer, and the 4-pin end to the
3259 matching connector on the TeleDongle.
3260 Note that each MicroMaTch connector has an alignment pin that
3261 goes through a hole in the PC board when you have the cable
3267 Attach a battery to the TeleMetrum board if you're using one.
3272 Plug both the programmer and the TeleDongle into your computer's USB
3273 ports, and power up the programmer.
3278 Run AltosUI, and select 'Flash Image' from the File menu.
3283 Pick the programmer device from the list, identifying it as the
3289 Select the image you want put on the TeleDongle, which should have a
3290 name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
3291 in the default directory, if not you may have to poke around
3292 your system to find it.
3297 Make sure the configuration parameters are reasonable
3298 looking. If the serial number and/or RF configuration
3299 values aren't right, you'll need to change them. The TeleDongle
3300 serial number is on the “bottom” of the circuit board, and can
3301 usually be read through the translucent blue plastic case without
3302 needing to remove the board from the case.
3307 Hit the 'OK' button and the software should proceed to flash
3308 the TeleDongle with new firmware, showing a progress bar.
3313 Confirm that the TeleDongle board seems to have updated OK, which you
3314 can do by plugging in to it over USB and using a terminal program
3315 to connect to the board and issue the 'v' command to check
3316 the version, etc. Once you're happy, remove the programming cable
3317 and put the cover back on the TeleDongle.
3322 If something goes wrong, give it another try.
3327 Be careful removing the programming cable from the locking 8-pin
3328 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
3329 screwdriver or knife blade to gently pry the locking ears out
3330 slightly to extract the connector. We used a locking connector on
3331 TeleMetrum to help ensure that the cabling to companion boards
3332 used in a rocket don't ever come loose accidentally in flight.
3337 <title>Hardware Specifications</title>
3340 TeleMega Specifications
3345 Recording altimeter for model rocketry.
3350 Supports dual deployment and four auxiliary pyro channels
3351 (a total of 6 events).
3356 70cm 40mW ham-band transceiver for telemetry down-link.
3361 Barometric pressure sensor good to 100k feet MSL.
3366 1-axis high-g accelerometer for motor characterization, capable of
3372 9-axis IMU including integrated 3-axis accelerometer,
3373 3-axis gyroscope and 3-axis magnetometer.
3378 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
3383 On-board 8 Megabyte non-volatile memory for flight data storage.
3388 USB interface for battery charging, configuration, and data recovery.
3393 Fully integrated support for Li-Po rechargeable batteries.
3398 Uses Li-Po to fire e-matches, can be modified to support
3399 optional separate pyro battery if needed.
3404 3.25 x 1.25 inch board designed to fit inside 38mm air-frame coupler tube.
3411 TeleMetrum v2 Specifications
3416 Recording altimeter for model rocketry.
3421 Supports dual deployment (can fire 2 ejection charges).
3426 70cm, 40mW ham-band transceiver for telemetry down-link.
3431 Barometric pressure sensor good to 100k feet MSL.
3436 1-axis high-g accelerometer for motor characterization, capable of
3442 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
3447 On-board 8 Megabyte non-volatile memory for flight data storage.
3452 USB interface for battery charging, configuration, and data recovery.
3457 Fully integrated support for Li-Po rechargeable batteries.
3462 Uses Li-Po to fire e-matches, can be modified to support
3463 optional separate pyro battery if needed.
3468 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
3474 <title>TeleMetrum v1 Specifications</title>
3478 Recording altimeter for model rocketry.
3483 Supports dual deployment (can fire 2 ejection charges).
3488 70cm, 10mW ham-band transceiver for telemetry down-link.
3493 Barometric pressure sensor good to 45k feet MSL.
3498 1-axis high-g accelerometer for motor characterization, capable of
3499 +/- 50g using default part.
3504 On-board, integrated GPS receiver with 5Hz update rate capability.
3509 On-board 1 megabyte non-volatile memory for flight data storage.
3514 USB interface for battery charging, configuration, and data recovery.
3519 Fully integrated support for Li-Po rechargeable batteries.
3524 Uses Li-Po to fire e-matches, can be modified to support
3525 optional separate pyro battery if needed.
3530 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
3537 TeleMini v2.0 Specifications
3542 Recording altimeter for model rocketry.
3547 Supports dual deployment (can fire 2 ejection charges).
3552 70cm, 10mW ham-band transceiver for telemetry down-link.
3557 Barometric pressure sensor good to 100k feet MSL.
3562 On-board 1 megabyte non-volatile memory for flight data storage.
3567 USB interface for configuration, and data recovery.
3572 Support for Li-Po rechargeable batteries (using an
3573 external charger), or any 3.7-15V external battery.
3578 Uses Li-Po to fire e-matches, can be modified to support
3579 optional separate pyro battery if needed.
3584 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
3591 TeleMini v1.0 Specifications
3596 Recording altimeter for model rocketry.
3601 Supports dual deployment (can fire 2 ejection charges).
3606 70cm, 10mW ham-band transceiver for telemetry down-link.
3611 Barometric pressure sensor good to 45k feet MSL.
3616 On-board 5 kilobyte non-volatile memory for flight data storage.
3621 RF interface for configuration, and data recovery.
3626 Support for Li-Po rechargeable batteries, using an external charger.
3631 Uses Li-Po to fire e-matches, can be modified to support
3632 optional separate pyro battery if needed.
3637 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube.
3644 EasyMini Specifications
3649 Recording altimeter for model rocketry.
3654 Supports dual deployment (can fire 2 ejection charges).
3659 Barometric pressure sensor good to 100k feet MSL.
3664 On-board 1 megabyte non-volatile memory for flight data storage.
3669 USB interface for configuration, and data recovery.
3674 Support for Li-Po rechargeable batteries (using an
3675 external charger), or any 3.7-15V external battery.
3680 Uses Li-Po to fire e-matches, can be modified to support
3681 optional separate pyro battery if needed.
3686 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
3695 TeleMetrum seems to shut off when disconnected from the
3696 computer. Make sure the battery is adequately charged. Remember the
3697 unit will pull more power than the USB port can deliver before the
3698 GPS enters “locked” mode. The battery charges best when TeleMetrum
3702 It's impossible to stop the TeleDongle when it's in “p” mode, I have
3703 to unplug the USB cable? Make sure you have tried to “escape out” of
3704 this mode. If this doesn't work the reboot procedure for the
3705 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
3706 outgoing buffer IF your “escape out” ('~~') does not work.
3707 At this point using either 'ao-view' (or possibly
3708 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
3712 The amber LED (on the TeleMetrum) lights up when both
3713 battery and USB are connected. Does this mean it's charging?
3714 Yes, the yellow LED indicates the charging at the 'regular' rate.
3715 If the led is out but the unit is still plugged into a USB port,
3716 then the battery is being charged at a 'trickle' rate.
3719 There are no “dit-dah-dah-dit” sound or lights like the manual mentions?
3720 That's the “pad” mode. Weak batteries might be the problem.
3721 It is also possible that the TeleMetrum is horizontal and the output
3722 is instead a “dit-dit” meaning 'idle'. For TeleMini, it's possible that
3723 it received a command packet which would have left it in “pad” mode.
3726 How do I save flight data?
3727 Live telemetry is written to file(s) whenever AltosUI is connected
3728 to the TeleDongle. The file area defaults to ~/TeleMetrum
3729 but is easily changed using the menus in AltosUI. The files that
3730 are written end in '.telem'. The after-flight
3731 data-dumped files will end in .eeprom and represent continuous data
3732 unlike the .telem files that are subject to losses
3733 along the RF data path.
3734 See the above instructions on what and how to save the eeprom stored
3735 data after physically retrieving your altimeter. Make sure to save
3736 the on-board data after each flight; while the TeleMetrum can store
3737 multiple flights, you never know when you'll lose the altimeter...
3741 <title>Notes for Older Software</title>
3744 Before AltosUI was written, using Altus Metrum devices required
3745 some finesse with the Linux command line. There was a limited
3746 GUI tool, ao-view, which provided functionality similar to the
3747 Monitor Flight window in AltosUI, but everything else was a
3748 fairly 80's experience. This appendix includes documentation for
3749 using that software.
3753 Both TeleMetrum and TeleDongle can be directly communicated
3754 with using USB ports. The first thing you should try after getting
3755 both units plugged into to your computer's USB port(s) is to run
3756 'ao-list' from a terminal-window to see what port-device-name each
3757 device has been assigned by the operating system.
3758 You will need this information to access the devices via their
3759 respective on-board firmware and data using other command line
3760 programs in the AltOS software suite.
3763 TeleMini can be communicated with through a TeleDongle device
3764 over the radio link. When first booted, TeleMini listens for a
3765 TeleDongle device and if it receives a packet, it goes into
3766 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be
3767 launched. The easiest way to get it talking is to start the
3768 communication link on the TeleDongle and the power up the
3772 To access the device's firmware for configuration you need a terminal
3773 program such as you would use to talk to a modem. The software
3774 authors prefer using the program 'cu' which comes from the UUCP package
3775 on most Unix-like systems such as Linux. An example command line for
3776 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
3777 indicated from running the
3778 ao-list program. Another reasonable terminal program for Linux is
3779 'cutecom'. The default 'escape'
3780 character used by CU (i.e. the character you use to
3781 issue commands to cu itself instead of sending the command as input
3782 to the connected device) is a '~'. You will need this for use in
3783 only two different ways during normal operations. First is to exit
3784 the program by sending a '~.' which is called a 'escape-disconnect'
3785 and allows you to close-out from 'cu'. The
3786 second use will be outlined later.
3789 All of the Altus Metrum devices share the concept of a two level
3790 command set in their firmware.
3791 The first layer has several single letter commands. Once
3792 you are using 'cu' (or 'cutecom') sending (typing) a '?'
3793 returns a full list of these
3794 commands. The second level are configuration sub-commands accessed
3795 using the 'c' command, for
3796 instance typing 'c?' will give you this second level of commands
3797 (all of which require the
3798 letter 'c' to access). Please note that most configuration options
3799 are stored only in Flash memory; TeleDongle doesn't provide any storage
3800 for these options and so they'll all be lost when you unplug it.
3803 Try setting these configuration ('c' or second level menu) values. A good
3804 place to start is by setting your call sign. By default, the boards
3805 use 'N0CALL' which is cute, but not exactly legal!
3806 Spend a few minutes getting comfortable with the units, their
3807 firmware, and 'cu' (or possibly 'cutecom').
3808 For instance, try to send
3809 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
3810 Verify you can connect and disconnect from the units while in your
3811 terminal program by sending the escape-disconnect mentioned above.
3814 To set the radio frequency, use the 'c R' command to specify the
3815 radio transceiver configuration parameter. This parameter is computed
3816 using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
3817 the standard calibration reference frequency, 'S', (normally 434.550MHz):
3821 Round the result to the nearest integer value.
3822 As with all 'c' sub-commands, follow this with a 'c w' to write the
3823 change to the parameter block in the on-board flash on
3824 your altimeter board if you want the change to stay in place across reboots.
3827 To set the apogee delay, use the 'c d' command.
3828 As with all 'c' sub-commands, follow this with a 'c w' to write the
3829 change to the parameter block in the on-board DataFlash chip.
3832 To set the main deployment altitude, use the 'c m' command.
3833 As with all 'c' sub-commands, follow this with a 'c w' to write the
3834 change to the parameter block in the on-board DataFlash chip.
3837 To calibrate the radio frequency, connect the UHF antenna port to a
3838 frequency counter, set the board to 434.550MHz, and use the 'C'
3839 command to generate a CW carrier. Wait for the transmitter temperature
3840 to stabilize and the frequency to settle down.
3841 Then, divide 434.550 MHz by the
3842 measured frequency and multiply by the current radio cal value show
3843 in the 'c s' command. For an unprogrammed board, the default value
3844 is 1186611. Take the resulting integer and program it using the 'c f'
3845 command. Testing with the 'C' command again should show a carrier
3846 within a few tens of Hertz of the intended frequency.
3847 As with all 'c' sub-commands, follow this with a 'c w' to write the
3848 change to the parameter block in the on-board DataFlash chip.
3851 Note that the 'reboot' command, which is very useful on the altimeters,
3852 will likely just cause problems with the dongle. The *correct* way
3853 to reset the dongle is just to unplug and re-plug it.
3856 A fun thing to do at the launch site and something you can do while
3857 learning how to use these units is to play with the radio link access
3858 between an altimeter and the TeleDongle. Be aware that you *must* create
3859 some physical separation between the devices, otherwise the link will
3860 not function due to signal overload in the receivers in each device.
3863 Now might be a good time to take a break and read the rest of this
3864 manual, particularly about the two “modes” that the altimeters
3865 can be placed in. TeleMetrum uses the position of the device when booting
3866 up will determine whether the unit is in “pad” or “idle” mode. TeleMini
3867 enters “idle” mode when it receives a command packet within the first 5 seconds
3868 of being powered up, otherwise it enters “pad” mode.
3871 You can access an altimeter in idle mode from the TeleDongle's USB
3872 connection using the radio link
3873 by issuing a 'p' command to the TeleDongle. Practice connecting and
3874 disconnecting ('~~' while using 'cu') from the altimeter. If
3875 you cannot escape out of the “p” command, (by using a '~~' when in
3876 CU) then it is likely that your kernel has issues. Try a newer version.
3879 Using this radio link allows you to configure the altimeter, test
3880 fire e-matches and igniters from the flight line, check pyro-match
3881 continuity and so forth. You can leave the unit turned on while it
3882 is in 'idle mode' and then place the
3883 rocket vertically on the launch pad, walk away and then issue a
3884 reboot command. The altimeter will reboot and start sending data
3885 having changed to the “pad” mode. If the TeleDongle is not receiving
3886 this data, you can disconnect 'cu' from the TeleDongle using the
3887 procedures mentioned above and THEN connect to the TeleDongle from
3888 inside 'ao-view'. If this doesn't work, disconnect from the
3889 TeleDongle, unplug it, and try again after plugging it back in.
3892 In order to reduce the chance of accidental firing of pyrotechnic
3893 charges, the command to fire a charge is intentionally somewhat
3894 difficult to type, and the built-in help is slightly cryptic to
3895 prevent accidental echoing of characters from the help text back at
3896 the board from firing a charge. The command to fire the apogee
3897 drogue charge is 'i DoIt drogue' and the command to fire the main
3898 charge is 'i DoIt main'.
3901 On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
3902 and 'ao-view' will both auditorily announce and visually indicate
3904 Now you can launch knowing that you have a good data path and
3905 good satellite lock for flight data and recovery. Remember
3906 you MUST tell ao-view to connect to the TeleDongle explicitly in
3907 order for ao-view to be able to receive data.
3910 The altimeters provide RDF (radio direction finding) tones on
3911 the pad, during descent and after landing. These can be used to
3912 locate the rocket using a directional antenna; the signal
3913 strength providing an indication of the direction from receiver to rocket.
3916 TeleMetrum also provides GPS tracking data, which can further simplify
3917 locating the rocket once it has landed. (The last good GPS data
3918 received before touch-down will be on the data screen of 'ao-view'.)
3921 Once you have recovered the rocket you can download the eeprom
3922 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
3923 either a USB cable or over the radio link using TeleDongle.
3924 And by following the man page for 'ao-postflight' you can create
3925 various data output reports, graphs, and even KML data to see the
3926 flight trajectory in Google-earth. (Moving the viewing angle making
3927 sure to connect the yellow lines while in Google-earth is the proper
3931 As for ao-view.... some things are in the menu but don't do anything
3932 very useful. The developers have stopped working on ao-view to focus
3933 on a new, cross-platform ground station program. So ao-view may or
3934 may not be updated in the future. Mostly you just use
3935 the Log and Device menus. It has a wonderful display of the incoming
3936 flight data and I am sure you will enjoy what it has to say to you
3937 once you enable the voice output!
3941 <title>Drill Templates</title>
3943 These images, when printed, provide precise templates for the
3944 mounting holes in Altus Metrum flight computers
3947 <title>TeleMega template</title>
3949 TeleMega has overall dimensions of 1.250 x 3.250 inches, and
3950 the mounting holes are sized for use with 4-40 or M3 screws.
3952 <mediaobject id="TeleMegaTemplate">
3954 <imagedata format="SVG" fileref="telemega-outline.svg"/>
3959 <title>TeleMetrum template</title>
3961 TeleMetrum has overall dimensions of 1.000 x 2.750 inches, and the
3962 mounting holes are sized for use with 4-40 or M3 screws.
3964 <mediaobject id="TeleMetrumTemplate">
3966 <imagedata format="SVG" fileref="telemetrum.svg"/>
3971 <title>TeleMini v2/EasyMini template</title>
3973 TeleMini v2 and EasyMini have overall dimensions of 0.800 x 1.500 inches, and the
3974 mounting holes are sized for use with 4-40 or M3 screws.
3976 <mediaobject id="MiniTemplate">
3978 <imagedata format="SVG" fileref="easymini-outline.svg"/>
3983 <title>TeleMini v1 template</title>
3985 TeleMini has overall dimensions of 0.500 x 1.500 inches, and the
3986 mounting holes are sized for use with 2-56 or M2 screws.
3988 <mediaobject id="TeleMiniTemplate">
3990 <imagedata format="SVG" fileref="telemini.svg"/>
3996 <title>Calibration</title>
3998 There are only two calibrations required for TeleMetrum and
3999 TeleMega, and only one for TeleDongle, TeleMini and EasyMini.
4000 All boards are shipped from the factory pre-calibrated, but
4001 the procedures are documented here in case they are ever
4002 needed. Re-calibration is not supported by AltosUI, you must
4003 connect to the board with a serial terminal program and
4004 interact directly with the on-board command interpreter to
4008 <title>Radio Frequency</title>
4010 The radio frequency is synthesized from a clock based on the
4011 crystal on the board. The actual frequency of this oscillator
4012 must be measured to generate a calibration constant. While our
4014 bandwidth is wide enough to allow boards to communicate even when
4015 their oscillators are not on exactly the same frequency, performance
4016 is best when they are closely matched.
4017 Radio frequency calibration requires a calibrated frequency counter.
4018 Fortunately, once set, the variation in frequency due to aging and
4019 temperature changes is small enough that re-calibration by customers
4020 should generally not be required.
4023 To calibrate the radio frequency, connect the UHF antenna
4024 port to a frequency counter, set the board to 434.550MHz,
4025 and use the 'C' command in the on-board command interpreter
4026 to generate a CW carrier. For USB-enabled boards, this is
4027 best done over USB. For TeleMini v1, note that the only way
4028 to escape the 'C' command is via power cycle since the board
4029 will no longer be listening for commands once it starts
4030 generating a CW carrier.
4033 Wait for the transmitter temperature to stabilize and the frequency
4034 to settle down. Then, divide 434.550 MHz by the
4035 measured frequency and multiply by the current radio cal value show
4036 in the 'c s' command. For an unprogrammed board, the default value
4037 is 1186611. Take the resulting integer and program it using the 'c f'
4038 command. Testing with the 'C' command again should show a carrier
4039 within a few tens of Hertz of the intended frequency.
4040 As with all 'c' sub-commands, follow this with a 'c w' to write the
4041 change to the parameter block in the on-board storage chip.
4044 Note that any time you re-do the radio frequency calibration, the
4045 radio frequency is reset to the default 434.550 Mhz. If you want
4046 to use another frequency, you will have to set that again after
4047 calibration is completed.
4051 <title>TeleMetrum and TeleMega Accelerometers</title>
4053 While barometric sensors are factory-calibrated,
4054 accelerometers are not, and so each must be calibrated once
4055 installed in a flight computer. Explicitly calibrating the
4056 accelerometers also allows us to load any compatible device.
4057 We perform a two-point calibration using gravity.
4060 To calibrate the acceleration sensor, use the 'c a 0' command. You
4061 will be prompted to orient the board vertically with the UHF antenna
4062 up and press a key, then to orient the board vertically with the
4063 UHF antenna down and press a key. Note that the accuracy of this
4064 calibration depends primarily on how perfectly vertical and still
4065 the board is held during the cal process. As with all 'c'
4066 sub-commands, follow this with a 'c w' to write the
4067 change to the parameter block in the on-board DataFlash chip.
4070 The +1g and -1g calibration points are included in each telemetry
4071 frame and are part of the header stored in onboard flash to be
4072 downloaded after flight. We always store and return raw ADC
4073 samples for each sensor... so nothing is permanently “lost” or
4074 “damaged” if the calibration is poor.
4077 In the unlikely event an accel cal goes badly, it is possible
4078 that TeleMetrum or TeleMega may always come up in 'pad mode'
4079 and as such not be listening to either the USB or radio link.
4080 If that happens, there is a special hook in the firmware to
4081 force the board back in to 'idle mode' so you can re-do the
4082 cal. To use this hook, you just need to ground the SPI clock
4083 pin at power-on. This pin is available as pin 2 on the 8-pin
4084 companion connector, and pin 1 is ground. So either
4085 carefully install a fine-gauge wire jumper between the two
4086 pins closest to the index hole end of the 8-pin connector, or
4087 plug in the programming cable to the 8-pin connector and use
4088 a small screwdriver or similar to short the two pins closest
4089 to the index post on the 4-pin end of the programming cable,
4090 and power up the board. It should come up in 'idle mode'
4091 (two beeps), allowing a re-cal.
4096 <title>Release Notes</title>
4098 <title>Version 1.3</title>
4100 xmlns:xi="http://www.w3.org/2001/XInclude"
4101 href="release-notes-1.3.xsl"
4102 xpointer="xpointer(/article/*)"/>
4105 <title>Version 1.2.1</title>
4107 xmlns:xi="http://www.w3.org/2001/XInclude"
4108 href="release-notes-1.2.1.xsl"
4109 xpointer="xpointer(/article/*)"/>
4112 <title>Version 1.2</title>
4114 xmlns:xi="http://www.w3.org/2001/XInclude"
4115 href="release-notes-1.2.xsl"
4116 xpointer="xpointer(/article/*)"/>
4119 <title>Version 1.1.1</title>
4121 xmlns:xi="http://www.w3.org/2001/XInclude"
4122 href="release-notes-1.1.1.xsl"
4123 xpointer="xpointer(/article/*)"/>
4126 <title>Version 1.1</title>
4128 xmlns:xi="http://www.w3.org/2001/XInclude"
4129 href="release-notes-1.1.xsl"
4130 xpointer="xpointer(/article/*)"/>
4133 <title>Version 1.0.1</title>
4135 xmlns:xi="http://www.w3.org/2001/XInclude"
4136 href="release-notes-1.0.1.xsl"
4137 xpointer="xpointer(/article/*)"/>
4140 <title>Version 0.9.2</title>
4142 xmlns:xi="http://www.w3.org/2001/XInclude"
4143 href="release-notes-0.9.2.xsl"
4144 xpointer="xpointer(/article/*)"/>
4147 <title>Version 0.9</title>
4149 xmlns:xi="http://www.w3.org/2001/XInclude"
4150 href="release-notes-0.9.xsl"
4151 xpointer="xpointer(/article/*)"/>
4154 <title>Version 0.8</title>
4156 xmlns:xi="http://www.w3.org/2001/XInclude"
4157 href="release-notes-0.8.xsl"
4158 xpointer="xpointer(/article/*)"/>
4161 <title>Version 0.7.1</title>
4163 xmlns:xi="http://www.w3.org/2001/XInclude"
4164 href="release-notes-0.7.1.xsl"
4165 xpointer="xpointer(/article/*)"/>
4170 <!-- LocalWords: Altusmetrum
projects / fw / altos / blob