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2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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5 <title>The Altus Metrum System</title>
6 <subtitle>An Owner's Manual for Altus Metrum Rocketry Electronics</subtitle>
9 <firstname>Bdale</firstname>
10 <surname>Garbee</surname>
13 <firstname>Keith</firstname>
14 <surname>Packard</surname>
17 <firstname>Bob</firstname>
18 <surname>Finch</surname>
21 <firstname>Anthony</firstname>
22 <surname>Towns</surname>
26 <holder>Bdale Garbee and Keith Packard</holder>
30 This document is released under the terms of the
31 <ulink url="http://creativecommons.org/licenses/by-sa/3.0/">
32 Creative Commons ShareAlike 3.0
39 <revnumber>1.3</revnumber>
40 <date>12 November 2013</date>
42 Updated for software version 1.3. Version 1.3 adds support
43 for TeleMega, TeleMetrum v2.0, TeleMini v2.0 and EasyMini
44 and fixes bugs in AltosUI and the AltOS firmware.
48 <revnumber>1.2.1</revnumber>
49 <date>21 May 2013</date>
51 Updated for software version 1.2. Version 1.2 adds support
52 for TeleBT and AltosDroid. It also adds a few minor features
53 and fixes bugs in AltosUI and the AltOS firmware.
57 <revnumber>1.2</revnumber>
58 <date>18 April 2013</date>
60 Updated for software version 1.2. Version 1.2 adds support
61 for MicroPeak and the MicroPeak USB interface.
65 <revnumber>1.1.1</revnumber>
66 <date>16 September 2012</date>
68 Updated for software version 1.1.1 Version 1.1.1 fixes a few
69 bugs found in version 1.1.
73 <revnumber>1.1</revnumber>
74 <date>13 September 2012</date>
76 Updated for software version 1.1. Version 1.1 has new
77 features but is otherwise compatible with version 1.0.
81 <revnumber>1.0</revnumber>
82 <date>24 August 2011</date>
84 Updated for software version 1.0. Note that 1.0 represents a
85 telemetry format change, meaning both ends of a link
86 (TeleMetrum/TeleMini and TeleDongle) must be updated or
87 communications will fail.
91 <revnumber>0.9</revnumber>
92 <date>18 January 2011</date>
94 Updated for software version 0.9. Note that 0.9 represents a
95 telemetry format change, meaning both ends of a link (TeleMetrum and
96 TeleDongle) must be updated or communications will fail.
100 <revnumber>0.8</revnumber>
101 <date>24 November 2010</date>
102 <revremark>Updated for software version 0.8 </revremark>
107 <title>Acknowledgments</title>
109 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing “The
110 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
111 Kit” which formed the basis of the original Getting Started chapter
112 in this manual. Bob was one of our first customers for a production
113 TeleMetrum, and his continued enthusiasm and contributions
114 are immensely gratifying and highly appreciated!
117 And thanks to Anthony (AJ) Towns for major contributions including
118 the AltosUI graphing and site map code and associated documentation.
119 Free software means that our customers and friends can become our
120 collaborators, and we certainly appreciate this level of
124 Have fun using these products, and we hope to meet all of you
125 out on the rocket flight line somewhere.
128 NAR #87103, TRA #12201
130 Keith Packard, KD7SQG
131 NAR #88757, TRA #12200
136 <title>Introduction and Overview</title>
138 Welcome to the Altus Metrum community! Our circuits and software reflect
139 our passion for both hobby rocketry and Free Software. We hope their
140 capabilities and performance will delight you in every way, but by
141 releasing all of our hardware and software designs under open licenses,
142 we also hope to empower you to take as active a role in our collective
146 The first device created for our community was TeleMetrum, a dual
147 deploy altimeter with fully integrated GPS and radio telemetry
148 as standard features, and a “companion interface” that will
149 support optional capabilities in the future. The latest version
150 of TeleMetrum, v2.0, has all of the same features but with
151 improved sensors and radio to offer increased performance.
154 Our second device was TeleMini, a dual deploy altimeter with
155 radio telemetry and radio direction finding. The first version
156 of this device was only 13mm by 38mm (½ inch by 1½ inches) and
157 could fit easily in an 18mm air-frame. The latest version, v2.0,
158 includes a beeper, USB data download and extended on-board
159 flight logging, along with an improved barometric sensor.
162 TeleMega is our most sophisticated device, including six pyro
163 channels (four of which are fully programmable), integrated GPS,
164 integrated gyroscopes for staging/air-start inhibit and high
165 performance telemetry.
168 EasyMini is a dual-deploy altimeter with logging and built-in
172 TeleDongle was our first ground station, providing a USB to RF
173 interfaces for communicating with the altimeters. Combined with
174 your choice of antenna and notebook computer, TeleDongle and our
175 associated user interface software form a complete ground
176 station capable of logging and displaying in-flight telemetry,
177 aiding rocket recovery, then processing and archiving flight
178 data for analysis and review.
181 For a slightly more portable ground station experience that also
182 provides direct rocket recovery support, TeleBT offers flight
183 monitoring and data logging using a Bluetooth™ connection between
184 the receiver and an Android device that has the AltosDroid
185 application installed from the Google Play store.
188 More products will be added to the Altus Metrum family over time, and
189 we currently envision that this will be a single, comprehensive manual
190 for the entire product family.
194 <title>Getting Started</title>
196 The first thing to do after you check the inventory of parts in your
197 “starter kit” is to charge the battery.
200 For TeleMetrum and TeleMega, the battery can be charged by plugging it into the
201 corresponding socket of the device and then using the USB
202 cable to plug the flight computer into your computer's USB socket. The
203 on-board circuitry will charge the battery whenever it is plugged
204 in, because the on-off switch does NOT control the
208 On TeleMetrum v1 boards, when the GPS chip is initially
209 searching for satellites, TeleMetrum will consume more current
210 than it pulls from the USB port, so the battery must be
211 attached in order to get satellite lock. Once GPS is locked,
212 the current consumption goes back down enough to enable charging
213 while running. So it's a good idea to fully charge the battery
214 as your first item of business so there is no issue getting and
215 maintaining satellite lock. The yellow charge indicator led
216 will go out when the battery is nearly full and the charger goes
217 to trickle charge. It can take several hours to fully recharge a
218 deeply discharged battery.
221 TeleMetrum v2.0 and TeleMega use a higher power battery charger,
222 allowing them to charge the battery while running the board at
223 maximum power. When the battery is charging, or when the board
224 is consuming a lot of power, the red LED will be lit. When the
225 battery is fully charged, the green LED will be lit. When the
226 battery is damaged or missing, both LEDs will be lit, which
230 The Lithium Polymer TeleMini and EasyMini battery can be charged by
231 disconnecting it from the board and plugging it into a
232 standalone battery charger such as the LipoCharger product
233 included in TeleMini Starter Kits, and connecting that via a USB
234 cable to a laptop or other USB power source.
237 You can also choose to use another battery with TeleMini v2.0
238 and EasyMini, anything supplying between 4 and 12 volts should
239 work fine (like a standard 9V battery), but if you are planning
240 to fire pyro charges, ground testing is required to verify that
241 the battery supplies enough current to fire your chosen e-matches.
244 The other active device in the starter kit is the TeleDongle USB to
245 RF interface. If you plug it in to your Mac or Linux computer it should
246 “just work”, showing up as a serial port device. Windows systems need
247 driver information that is part of the AltOS download to know that the
248 existing USB modem driver will work. We therefore recommend installing
249 our software before plugging in TeleDongle if you are using a Windows
250 computer. If you are using an older version of Linux and are having
251 problems, try moving to a fresher kernel (2.6.33 or newer).
254 Next you should obtain and install the AltOS software. The AltOS
255 distribution includes the AltosUI ground station program, current
257 images for all of the hardware, and a number of standalone
258 utilities that are rarely needed. Pre-built binary packages are
259 available for Linux, Microsoft Windows, and recent MacOSX
260 versions. Full source code and build instructions are also
261 available. The latest version may always be downloaded from
262 <ulink url="http://altusmetrum.org/AltOS"/>.
265 If you're using a TeleBT instead of the TeleDongle, you'll want to
266 install the AltosDroid application from the Google Play store on an
267 Android device. You don't need a data plan to use AltosDroid, but
268 without network access, the Map view will be less useful as it
269 won't contain any map data. You can also use TeleBT connected
270 over USB with your laptop computer; it acts exactly like a
271 TeleDongle. Anywhere this manual talks about TeleDongle, you can
272 also read that as 'and TeleBT when connected via USB'.
276 <title>Handling Precautions</title>
278 All Altus Metrum products are sophisticated electronic devices.
279 When handled gently and properly installed in an air-frame, they
280 will deliver impressive results. However, as with all electronic
281 devices, there are some precautions you must take.
284 The Lithium Polymer rechargeable batteries have an
285 extraordinary power density. This is great because we can fly with
286 much less battery mass than if we used alkaline batteries or previous
287 generation rechargeable batteries... but if they are punctured
288 or their leads are allowed to short, they can and will release their
290 Thus we recommend that you take some care when handling our batteries
291 and consider giving them some extra protection in your air-frame. We
292 often wrap them in suitable scraps of closed-cell packing foam before
293 strapping them down, for example.
296 The barometric sensors used on all of our flight computers are
297 sensitive to sunlight. In normal mounting situations, the baro sensor
298 and all of the other surface mount components
299 are “down” towards whatever the underlying mounting surface is, so
300 this is not normally a problem. Please consider this when designing an
301 installation in an air-frame with a see-through plastic payload bay. It
302 is particularly important to
303 consider this with TeleMini v1.0, both because the baro sensor is on the
304 “top” of the board, and because many model rockets with payload bays
305 use clear plastic for the payload bay! Replacing these with an opaque
306 cardboard tube, painting them, or wrapping them with a layer of masking
307 tape are all reasonable approaches to keep the sensor out of direct
311 The barometric sensor sampling port must be able to “breathe”,
312 both by not being covered by foam or tape or other materials that might
313 directly block the hole on the top of the sensor, and also by having a
314 suitable static vent to outside air.
317 As with all other rocketry electronics, Altus Metrum altimeters must
318 be protected from exposure to corrosive motor exhaust and ejection
323 <title>Altus Metrum Hardware</title>
325 <title>Overview</title>
327 Here's the full set of Altus Metrum products, both in
328 production and retired.
331 <title>Altus Metrum Electronics</title>
332 <?dbfo keep-together="always"?>
333 <tgroup cols='8' align='center' colsep='1' rowsep='1'>
334 <colspec align='center' colwidth='*' colname='Device'/>
335 <colspec align='center' colwidth='*' colname='Barometer'/>
336 <colspec align='center' colwidth='*' colname='Z-axis accelerometer'/>
337 <colspec align='center' colwidth='*' colname='GPS'/>
338 <colspec align='center' colwidth='*' colname='3D sensors'/>
339 <colspec align='center' colwidth='*' colname='Storage'/>
340 <colspec align='center' colwidth='*' colname='RF'/>
341 <colspec align='center' colwidth='*' colname='Battery'/>
344 <entry align='center'>Device</entry>
345 <entry align='center'>Barometer</entry>
346 <entry align='center'>Z-axis accelerometer</entry>
347 <entry align='center'>GPS</entry>
348 <entry align='center'>3D sensors</entry>
349 <entry align='center'>Storage</entry>
350 <entry align='center'>RF Output</entry>
351 <entry align='center'>Battery</entry>
356 <entry>TeleMetrum v1.0</entry>
357 <entry><para>MP3H6115 10km (33k')</para></entry>
358 <entry><para>MMA2202 50g</para></entry>
359 <entry>SkyTraq</entry>
366 <entry>TeleMetrum v1.1</entry>
367 <entry><para>MP3H6115 10km (33k')</para></entry>
368 <entry><para>MMA2202 50g</para></entry>
369 <entry>SkyTraq</entry>
376 <entry>TeleMetrum v1.2</entry>
377 <entry><para>MP3H6115 10km (33k')</para></entry>
378 <entry><para>ADXL78 70g</para></entry>
379 <entry>SkyTraq</entry>
386 <entry>TeleMetrum v2.0</entry>
387 <entry><para>MS5607 30km (100k')</para></entry>
388 <entry><para>MMA6555 102g</para></entry>
389 <entry>uBlox Max-7Q</entry>
396 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
397 <entry><para>MP3H6115 10km (33k')</para></entry>
406 <entry>TeleMini <?linebreak?>v2.0</entry>
407 <entry><para>MS5607 30km (100k')</para></entry>
413 <entry>3.7-12V</entry>
416 <entry>EasyMini <?linebreak?>v1.0</entry>
417 <entry><para>MS5607 30km (100k')</para></entry>
423 <entry>3.7-12V</entry>
426 <entry>TeleMega <?linebreak?>v1.0</entry>
427 <entry><para>MS5607 30km (100k')</para></entry>
428 <entry><para>MMA6555 102g</para></entry>
429 <entry>uBlox Max-7Q</entry>
430 <entry><para>MPU6000 HMC5883</para></entry>
439 <title>Altus Metrum Boards</title>
440 <?dbfo keep-together="always"?>
441 <tgroup cols='6' align='center' colsep='1' rowsep='1'>
442 <colspec align='center' colwidth='*' colname='Device'/>
443 <colspec align='center' colwidth='*' colname='Connectors'/>
444 <colspec align='center' colwidth='*' colname='Screw Terminals'/>
445 <colspec align='center' colwidth='*' colname='Width'/>
446 <colspec align='center' colwidth='*' colname='Length'/>
447 <colspec align='center' colwidth='*' colname='Tube Size'/>
450 <entry align='center'>Device</entry>
451 <entry align='center'>Connectors</entry>
452 <entry align='center'>Screw Terminals</entry>
453 <entry align='center'>Width</entry>
454 <entry align='center'>Length</entry>
455 <entry align='center'>Tube Size</entry>
460 <entry>TeleMetrum</entry>
464 Companion<?linebreak?>
468 <entry><para>Apogee pyro <?linebreak?>Main pyro <?linebreak?>Switch</para></entry>
469 <entry>1 inch (2.54cm)</entry>
470 <entry>2 ¾ inch (6.99cm)</entry>
471 <entry>29mm coupler</entry>
474 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
481 Apogee pyro <?linebreak?>
484 <entry>½ inch (1.27cm)</entry>
485 <entry>1½ inch (3.81cm)</entry>
486 <entry>18mm coupler</entry>
489 <entry>TeleMini <?linebreak?>v2.0</entry>
497 Apogee pyro <?linebreak?>
498 Main pyro <?linebreak?>
499 Battery <?linebreak?>
502 <entry>0.8 inch (2.03cm)</entry>
503 <entry>1½ inch (3.81cm)</entry>
504 <entry>24mm coupler</entry>
507 <entry>EasyMini</entry>
514 Apogee pyro <?linebreak?>
515 Main pyro <?linebreak?>
516 Battery <?linebreak?>
519 <entry>0.8 inch (2.03cm)</entry>
520 <entry>1½ inch (3.81cm)</entry>
521 <entry>24mm coupler</entry>
524 <entry>TeleMega</entry>
528 Companion<?linebreak?>
533 Apogee pyro <?linebreak?>
534 Main pyro<?linebreak?>
535 Pyro A-D<?linebreak?>
539 <entry>1¼ inch (3.18cm)</entry>
540 <entry>3¼ inch (8.26cm)</entry>
541 <entry>38mm coupler</entry>
548 <title>TeleMetrum</title>
552 <imagedata fileref="telemetrum-v1.1-thside.jpg" width="5.5in" scalefit="1"/>
557 TeleMetrum is a 1 inch by 2¾ inch circuit board. It was designed to
558 fit inside coupler for 29mm air-frame tubing, but using it in a tube that
559 small in diameter may require some creativity in mounting and wiring
560 to succeed! The presence of an accelerometer means TeleMetrum should
561 be aligned along the flight axis of the airframe, and by default the ¼
562 wave UHF wire antenna should be on the nose-cone end of the board. The
563 antenna wire is about 7 inches long, and wiring for a power switch and
564 the e-matches for apogee and main ejection charges depart from the
565 fin can end of the board, meaning an ideal “simple” avionics
566 bay for TeleMetrum should have at least 10 inches of interior length.
570 <title>TeleMini</title>
574 <imagedata fileref="telemini-v1-top.jpg" width="5.5in" scalefit="1"/>
579 TeleMini v1.0 is ½ inches by 1½ inches. It was
580 designed to fit inside an 18mm air-frame tube, but using it in
581 a tube that small in diameter may require some creativity in
582 mounting and wiring to succeed! Since there is no
583 accelerometer, TeleMini can be mounted in any convenient
584 orientation. The default ¼ wave UHF wire antenna attached to
585 the center of one end of the board is about 7 inches long. Two
586 wires for the power switch are connected to holes in the
587 middle of the board. Screw terminals for the e-matches for
588 apogee and main ejection charges depart from the other end of
589 the board, meaning an ideal “simple” avionics bay for TeleMini
590 should have at least 9 inches of interior length.
595 <imagedata fileref="telemini-v2-top.jpg" width="5.5in" scalefit="1"/>
600 TeleMini v2.0 is 0.8 inches by 1½ inches. It adds more
601 on-board data logging memory, a built-in USB connector and
602 screw terminals for the battery and power switch. The larger
603 board fits in a 24mm coupler. There's also a battery connector
604 for a LiPo battery if you want to use one of those.
608 <title>EasyMini</title>
612 <imagedata fileref="easymini-top.jpg" width="5.5in" scalefit="1"/>
617 EasyMini is built on a 0.8 inch by 1½ inch circuit board. It's
618 designed to fit in a 24mm coupler tube. The connectors and
619 screw terminals match TeleMini v2.0, so you can easily swap between
620 EasyMini and TeleMini.
624 <title>TeleMega</title>
628 <imagedata fileref="telemega-v1.0-top.jpg" width="5.5in" scalefit="1"/>
633 TeleMega is a 1¼ inch by 3¼ inch circuit board. It was
634 designed to easily fit in a 38mm coupler. Like TeleMetrum,
635 TeleMega has an accelerometer and so it must be mounted so that
636 the board is aligned with the flight axis. It can be mounted
637 either antenna up or down.
641 <title>Flight Data Recording</title>
643 Each flight computer logs data at 100 samples per second
644 during ascent and 10 samples per second during descent, except
645 for TeleMini v1.0, which records ascent at 10 samples per
646 second and descent at 1 sample per second. Data are logged to
647 an on-board flash memory part, which can be partitioned into
648 several equal-sized blocks, one for each flight.
651 <title>Data Storage on Altus Metrum altimeters</title>
652 <?dbfo keep-together="always"?>
653 <tgroup cols='4' align='center' colsep='1' rowsep='1'>
654 <colspec align='center' colwidth='*' colname='Device'/>
655 <colspec align='center' colwidth='*' colname='Bytes per sample'/>
656 <colspec align='center' colwidth='*' colname='Total storage'/>
657 <colspec align='center' colwidth='*' colname='Minutes of
661 <entry align='center'>Device</entry>
662 <entry align='center'>Bytes per Sample</entry>
663 <entry align='center'>Total Storage</entry>
664 <entry align='center'>Minutes at Full Rate</entry>
669 <entry>TeleMetrum v1.0</entry>
675 <entry>TeleMetrum v1.1 v1.2</entry>
681 <entry>TeleMetrum v2.0</entry>
687 <entry>TeleMini v1.0</entry>
693 <entry>TeleMini v2.0</entry>
699 <entry>EasyMini</entry>
705 <entry>TeleMega</entry>
714 The on-board flash is partitioned into separate flight logs,
715 each of a fixed maximum size. Increase the maximum size of
716 each log and you reduce the number of flights that can be
717 stored. Decrease the size and you can store more flights.
720 Configuration data is also stored in the flash memory on
721 TeleMetrum v1.x, TeleMini and EasyMini. This consumes 64kB
722 of flash space. This configuration space is not available
723 for storing flight log data. TeleMetrum v2.0 and TeleMega
724 store configuration data in a bit of eeprom available within
725 the processor chip, leaving that space available in flash for
729 To compute the amount of space needed for a single flight, you
730 can multiply the expected ascent time (in seconds) by 100
731 times bytes-per-sample, multiply the expected descent time (in
732 seconds) by 10 times the bytes per sample and add the two
733 together. That will slightly under-estimate the storage (in
734 bytes) needed for the flight. For instance, a TeleMetrum v2.0 flight spending
735 20 seconds in ascent and 150 seconds in descent will take
736 about (20 * 1600) + (150 * 160) = 56000 bytes of storage. You
737 could store dozens of these flights in the on-board flash.
740 The default size allows for several flights on each flight
741 computer, except for TeleMini v1.0, which only holds data for a
742 single flight. You can adjust the size.
745 Altus Metrum flight computers will not overwrite existing
746 flight data, so be sure to download flight data and erase it
747 from the flight computer before it fills up. The flight
748 computer will still successfully control the flight even if it
749 cannot log data, so the only thing you will lose is the data.
753 <title>Installation</title>
755 A typical installation involves attaching
756 only a suitable battery, a single pole switch for
757 power on/off, and two pairs of wires connecting e-matches for the
758 apogee and main ejection charges. All Altus Metrum products are
759 designed for use with single-cell batteries with 3.7 volts
760 nominal. TeleMini v2.0 and EasyMini may also be used with other
761 batteries as long as they supply between 4 and 12 volts.
764 The battery connectors are a standard 2-pin JST connector and
765 match batteries sold by Spark Fun. These batteries are
766 single-cell Lithium Polymer batteries that nominally provide 3.7
767 volts. Other vendors sell similar batteries for RC aircraft
768 using mating connectors, however the polarity for those is
769 generally reversed from the batteries used by Altus Metrum
770 products. In particular, the Tenergy batteries supplied for use
771 in Featherweight flight computers are not compatible with Altus
772 Metrum flight computers or battery chargers. <emphasis>Check
773 polarity and voltage before connecting any battery not purchased
774 from Altus Metrum or Spark Fun.</emphasis>
777 By default, we use the unregulated output of the battery directly
778 to fire ejection charges. This works marvelously with standard
779 low-current e-matches like the J-Tek from MJG Technologies, and with
780 Quest Q2G2 igniters. However, if you want or need to use a separate
781 pyro battery, check out the “External Pyro Battery” section in this
782 manual for instructions on how to wire that up. The altimeters are
783 designed to work with an external pyro battery of no more than 15 volts.
787 Ejection charges are wired directly to the screw terminal block
788 at the aft end of the altimeter. You'll need a very small straight
789 blade screwdriver for these screws, such as you might find in a
790 jeweler's screwdriver set.
793 Except for TeleMini v1.0, the flight computers also use the
794 screw terminal block for the power switch leads. On TeleMini v1.0,
795 the power switch leads are soldered directly to the board and
796 can be connected directly to a switch.
799 For most air-frames, the integrated antennas are more than
800 adequate. However, if you are installing in a carbon-fiber or
801 metal electronics bay which is opaque to RF signals, you may need to
802 use off-board external antennas instead. In this case, you can
803 replace the stock UHF antenna wire with an edge-launched SMA connector,
804 and, on TeleMetrum v1, you can unplug the integrated GPS
805 antenna and select an appropriate off-board GPS antenna with
806 cable terminating in a U.FL connector.
811 <title>System Operation</title>
813 <title>Firmware Modes </title>
815 The AltOS firmware build for the altimeters has two
816 fundamental modes, “idle” and “flight”. Which of these modes
817 the firmware operates in is determined at start up time. For
818 TeleMetrum and TeleMega, which have accelerometers, the mode is
819 controlled by the orientation of the
820 rocket (well, actually the board, of course...) at the time
821 power is switched on. If the rocket is “nose up”, then
822 the flight computer assumes it's on a rail or rod being prepared for
823 launch, so the firmware chooses flight mode. However, if the
824 rocket is more or less horizontal, the firmware instead enters
825 idle mode. Since TeleMini v2.0 and EasyMini don't have an
826 accelerometer we can use to determine orientation, “idle” mode
827 is selected if the board is connected via USB to a computer,
828 otherwise the board enters “flight” mode. TeleMini v1.0
829 selects “idle” mode if it receives a command packet within the
830 first five seconds of operation.
833 At power on, you will hear three beeps or see three flashes
834 (“S” in Morse code for start up) and then a pause while
835 the altimeter completes initialization and self test, and decides
836 which mode to enter next.
839 In flight or “pad” mode, the altimeter engages the flight
840 state machine, goes into transmit-only mode to
841 send telemetry, and waits for launch to be detected.
842 Flight mode is indicated by an “di-dah-dah-dit” (“P” for pad)
843 on the beeper or lights, followed by beeps or flashes
844 indicating the state of the pyrotechnic igniter continuity.
845 One beep/flash indicates apogee continuity, two beeps/flashes
846 indicate main continuity, three beeps/flashes indicate both
847 apogee and main continuity, and one longer “brap” sound or
848 rapidly alternating lights indicates no continuity. For a
849 dual deploy flight, make sure you're getting three beeps or
850 flashes before launching! For apogee-only or motor eject
851 flights, do what makes sense.
854 If idle mode is entered, you will hear an audible “di-dit” or
855 see two short flashes (“I” for idle), and the flight state
856 machine is disengaged, thus no ejection charges will fire.
857 The altimeters also listen for the radio link when in idle
858 mode for requests sent via TeleDongle. Commands can be issued
859 in idle mode over either USB or the radio link
860 equivalently. TeleMini v1.0 only has the radio link. Idle
861 mode is useful for configuring the altimeter, for extracting
862 data from the on-board storage chip after flight, and for
863 ground testing pyro charges.
866 One “neat trick” of particular value when TeleMetrum or TeleMega are used with
867 very large air-frames, is that you can power the board up while the
868 rocket is horizontal, such that it comes up in idle mode. Then you can
869 raise the air-frame to launch position, and issue a 'reset' command
870 via TeleDongle over the radio link to cause the altimeter to reboot and
871 come up in flight mode. This is much safer than standing on the top
872 step of a rickety step-ladder or hanging off the side of a launch
873 tower with a screw-driver trying to turn on your avionics before
877 TeleMini v1.0 is configured solely via the radio link. Of course, that
878 means you need to know the TeleMini radio configuration values
879 or you won't be able to communicate with it. For situations
880 when you don't have the radio configuration values, TeleMini v1.0
881 offers an 'emergency recovery' mode. In this mode, TeleMini is
882 configured as follows:
886 Sets the radio frequency to 434.550MHz
891 Sets the radio calibration back to the factory value.
896 Sets the callsign to N0CALL
901 Does not go to 'pad' mode after five seconds.
907 To get into 'emergency recovery' mode, first find the row of
908 four small holes opposite the switch wiring. Using a short
909 piece of small gauge wire, connect the outer two holes
910 together, then power TeleMini up. Once the red LED is lit,
911 disconnect the wire and the board should signal that it's in
912 'idle' mode after the initial five second startup period.
918 TeleMetrum and TeleMega include a complete GPS receiver. A
919 complete explanation of how GPS works is beyond the scope of
920 this manual, but the bottom line is that the GPS receiver
921 needs to lock onto at least four satellites to obtain a solid
922 3 dimensional position fix and know what time it is.
925 The flight computers provide backup power to the GPS chip any time a
926 battery is connected. This allows the receiver to “warm start” on
927 the launch rail much faster than if every power-on were a GPS
928 “cold start”. In typical operations, powering up
929 on the flight line in idle mode while performing final air-frame
930 preparation will be sufficient to allow the GPS receiver to cold
931 start and acquire lock. Then the board can be powered down during
932 RSO review and installation on a launch rod or rail. When the board
933 is turned back on, the GPS system should lock very quickly, typically
934 long before igniter installation and return to the flight line are
939 <title>Controlling An Altimeter Over The Radio Link</title>
941 One of the unique features of the Altus Metrum system is the
942 ability to create a two way command link between TeleDongle
943 and an altimeter using the digital radio transceivers
944 built into each device. This allows you to interact with the
945 altimeter from afar, as if it were directly connected to the
949 Any operation which can be performed with a flight computer can
950 either be done with the device directly connected to the
951 computer via the USB cable, or through the radio
952 link. TeleMini v1.0 doesn't provide a USB connector and so it is
953 always communicated with over radio. Select the appropriate
954 TeleDongle device when the list of devices is presented and
955 AltosUI will interact with an altimeter over the radio link.
958 One oddity in the current interface is how AltosUI selects the
959 frequency for radio communications. Instead of providing
960 an interface to specifically configure the frequency, it uses
961 whatever frequency was most recently selected for the target
962 TeleDongle device in Monitor Flight mode. If you haven't ever
963 used that mode with the TeleDongle in question, select the
964 Monitor Flight button from the top level UI, and pick the
965 appropriate TeleDongle device. Once the flight monitoring
966 window is open, select the desired frequency and then close it
967 down again. All radio communications will now use that frequency.
972 Save Flight Data—Recover flight data from the rocket without
978 Configure altimeter apogee delays, main deploy heights
979 and additional pyro event conditions
980 to respond to changing launch conditions. You can also
981 'reboot' the altimeter. Use this to remotely enable the
982 flight computer by turning TeleMetrum or TeleMega on in “idle” mode,
983 then once the air-frame is oriented for launch, you can
984 reboot the altimeter and have it restart in pad mode
985 without having to climb the scary ladder.
990 Fire Igniters—Test your deployment charges without snaking
991 wires out through holes in the air-frame. Simply assemble the
992 rocket as if for flight with the apogee and main charges
993 loaded, then remotely command the altimeter to fire the
999 Operation over the radio link for configuring an altimeter, ground
1000 testing igniters, and so forth uses the same RF frequencies as flight
1001 telemetry. To configure the desired TeleDongle frequency, select
1002 the monitor flight tab, then use the frequency selector and
1003 close the window before performing other desired radio operations.
1006 The flight computers only enable radio commanding in 'idle' mode.
1007 TeleMetrum and TeleMega use the accelerometer to detect which orientation they
1008 start up in, so make sure you have the flight computer lying horizontally when you turn
1009 it on. Otherwise, it will start in 'pad' mode ready for
1010 flight, and will not be listening for command packets from TeleDongle.
1013 TeleMini listens for a command packet for five seconds after
1014 first being turned on, if it doesn't hear anything, it enters
1015 'pad' mode, ready for flight and will no longer listen for
1016 command packets. The easiest way to connect to TeleMini is to
1017 initiate the command and select the TeleDongle device. At this
1018 point, the TeleDongle will be attempting to communicate with
1019 the TeleMini. Now turn TeleMini on, and it should immediately
1020 start communicating with the TeleDongle and the desired
1021 operation can be performed.
1024 You can monitor the operation of the radio link by watching the
1025 lights on the devices. The red LED will flash each time a packet
1026 is transmitted, while the green LED will light up on TeleDongle when
1027 it is waiting to receive a packet from the altimeter.
1031 <title>Ground Testing </title>
1033 An important aspect of preparing a rocket using electronic deployment
1034 for flight is ground testing the recovery system. Thanks
1035 to the bi-directional radio link central to the Altus Metrum system,
1036 this can be accomplished in a TeleMega, TeleMetrum or TeleMini equipped rocket
1037 with less work than you may be accustomed to with other systems. It
1041 Just prep the rocket for flight, then power up the altimeter
1042 in “idle” mode (placing air-frame horizontal for TeleMetrum or TeleMega, or
1043 selecting the Configure Altimeter tab for TeleMini). This will cause
1044 the firmware to go into “idle” mode, in which the normal flight
1045 state machine is disabled and charges will not fire without
1046 manual command. You can now command the altimeter to fire the apogee
1047 or main charges from a safe distance using your computer and
1048 TeleDongle and the Fire Igniter tab to complete ejection testing.
1052 <title>Radio Link </title>
1054 Our flight computers all incorporate an RF transceiver, but
1055 it's not a full duplex system... each end can only be transmitting or
1056 receiving at any given moment. So we had to decide how to manage the
1060 By design, the altimeter firmware listens for the radio link when
1061 it's in “idle mode”, which
1062 allows us to use the radio link to configure the rocket, do things like
1063 ejection tests, and extract data after a flight without having to
1064 crack open the air-frame. However, when the board is in “flight
1065 mode”, the altimeter only
1066 transmits and doesn't listen at all. That's because we want to put
1067 ultimate priority on event detection and getting telemetry out of
1069 the radio in case the rocket crashes and we aren't able to extract
1073 We don't generally use a 'normal packet radio' mode like APRS
1074 because they're just too inefficient. The GFSK modulation we
1075 use is FSK with the base-band pulses passed through a Gaussian
1076 filter before they go into the modulator to limit the
1077 transmitted bandwidth. When combined with forward error
1078 correction and interleaving, this allows us to have a very
1079 robust 19.2 kilobit data link with only 10-40 milliwatts of
1080 transmit power, a whip antenna in the rocket, and a hand-held
1081 Yagi on the ground. We've had flights to above 21k feet AGL
1082 with great reception, and calculations suggest we should be
1083 good to well over 40k feet AGL with a 5-element yagi on the
1084 ground with our 10mW units and over 100k feet AGL with the
1085 40mW devices. We hope to fly boards to higher altitudes over
1086 time, and would of course appreciate customer feedback on
1087 performance in higher altitude flights!
1090 TeleMetrum v2.0 and TeleMega can send APRS if desired, and the
1091 interval between APRS packets can be configured. As each APRS
1092 packet takes a full second to transmit, we recommend an
1093 interval of at least 5 seconds to avoid consuming too much
1094 battery power or radio channel bandwidth.
1098 <title>Configurable Parameters</title>
1100 Configuring an Altus Metrum altimeter for flight is very
1101 simple. Even on our baro-only TeleMini and EasyMini boards, the use of a Kalman
1102 filter means there is no need to set a “mach delay”. The few
1103 configurable parameters can all be set using AltosUI over USB or
1104 or radio link via TeleDongle.
1107 <title>Radio Frequency</title>
1109 Altus Metrum boards support radio frequencies in the 70cm
1110 band. By default, the configuration interface provides a
1111 list of 10 “standard” frequencies in 100kHz channels starting at
1112 434.550MHz. However, the firmware supports use of
1113 any 50kHz multiple within the 70cm band. At any given
1114 launch, we highly recommend coordinating when and by whom each
1115 frequency will be used to avoid interference. And of course, both
1116 altimeter and TeleDongle must be configured to the same
1117 frequency to successfully communicate with each other.
1121 <title>Apogee Delay</title>
1123 Apogee delay is the number of seconds after the altimeter detects flight
1124 apogee that the drogue charge should be fired. In most cases, this
1125 should be left at the default of 0. However, if you are flying
1126 redundant electronics such as for an L3 certification, you may wish
1127 to set one of your altimeters to a positive delay so that both
1128 primary and backup pyrotechnic charges do not fire simultaneously.
1131 The Altus Metrum apogee detection algorithm fires exactly at
1132 apogee. If you are also flying an altimeter like the
1133 PerfectFlite MAWD, which only supports selecting 0 or 1
1134 seconds of apogee delay, you may wish to set the MAWD to 0
1135 seconds delay and set the TeleMetrum to fire your backup 2
1136 or 3 seconds later to avoid any chance of both charges
1137 firing simultaneously. We've flown several air-frames this
1138 way quite happily, including Keith's successful L3 cert.
1142 <title>Main Deployment Altitude</title>
1144 By default, the altimeter will fire the main deployment charge at an
1145 elevation of 250 meters (about 820 feet) above ground. We think this
1146 is a good elevation for most air-frames, but feel free to change this
1147 to suit. In particular, if you are flying two altimeters, you may
1149 deployment elevation for the backup altimeter to be something lower
1150 than the primary so that both pyrotechnic charges don't fire
1155 <title>Maximum Flight Log</title>
1157 Changing this value will set the maximum amount of flight
1158 log storage that an individual flight will use. The
1159 available storage is divided into as many flights of the
1160 specified size as can fit in the available space. You can
1161 download and erase individual flight logs. If you fill up
1162 the available storage, future flights will not get logged
1163 until you erase some of the stored ones.
1166 Even though our flight computers (except TeleMini v1.0) can store
1167 multiple flights, we strongly recommend downloading and saving
1168 flight data after each flight.
1172 <title>Ignite Mode</title>
1174 Instead of firing one charge at apogee and another charge at
1175 a fixed height above the ground, you can configure the
1176 altimeter to fire both at apogee or both during
1177 descent. This was added to support an airframe Bdale designed that
1178 had two altimeters, one in the fin can and one in the nose.
1181 Providing the ability to use both igniters for apogee or
1182 main allows some level of redundancy without needing two
1183 flight computers. In Redundant Apogee or Redundant Main
1184 mode, the two charges will be fired two seconds apart.
1188 <title>Pad Orientation</title>
1190 TeleMetrum and TeleMega measure acceleration along the axis
1191 of the board. Which way the board is oriented affects the
1192 sign of the acceleration value. Instead of trying to guess
1193 which way the board is mounted in the air frame, the
1194 altimeter must be explicitly configured for either Antenna
1195 Up or Antenna Down. The default, Antenna Up, expects the end
1196 of the board connected to the 70cm antenna to be nearest the
1197 nose of the rocket, with the end containing the screw
1198 terminals nearest the tail.
1202 <title>Configurable Pyro Channels</title>
1204 In addition to the usual Apogee and Main pyro channels,
1205 TeleMega has four additional channels that can be configured
1206 to activate when various flight conditions are
1207 satisfied. You can select as many conditions as necessary;
1208 all of them must be met in order to activate the
1209 channel. The conditions available are:
1214 Acceleration away from the ground. Select a value, and
1215 then choose whether acceleration should be above or
1216 below that value. Acceleration is positive upwards, so
1217 accelerating towards the ground would produce negative
1218 numbers. Acceleration during descent is noisy and
1219 inaccurate, so be careful when using it during these
1220 phases of the flight.
1225 Vertical speed. Select a value, and then choose whether
1226 vertical speed should be above or below that
1227 value. Speed is positive upwards, so moving towards the
1228 ground would produce negative numbers. Speed during
1229 descent is a bit noisy and so be careful when using it
1230 during these phases of the flight.
1235 Height. Select a value, and then choose whether the
1236 height above the launch pad should be above or below
1242 Orientation. TeleMega contains a 3-axis gyroscope and
1243 accelerometer which is used to measure the current
1244 angle. Note that this angle is not the change in angle
1245 from the launch pad, but rather absolute relative to
1246 gravity; the 3-axis accelerometer is used to compute the
1247 angle of the rocket on the launch pad and initialize the
1248 system. Because this value is computed by integrating
1249 rate gyros, it gets progressively less accurate as the
1250 flight goes on. It should have an accumulated error of
1251 less than 0.2°/second (after 10 seconds of flight, the
1252 error should be less than 2°).
1255 The usual use of the orientation configuration is to
1256 ensure that the rocket is traveling mostly upwards when
1257 deciding whether to ignite air starts or additional
1258 stages. For that, choose a reasonable maximum angle
1259 (like 20°) and set the motor igniter to require an angle
1260 of less than that value.
1265 Flight Time. Time since boost was detected. Select a
1266 value and choose whether to activate the pyro channel
1267 before or after that amount of time.
1272 Ascending. A simple test saying whether the rocket is
1273 going up or not. This is exactly equivalent to testing
1274 whether the speed is > 0.
1279 Descending. A simple test saying whether the rocket is
1280 going down or not. This is exactly equivalent to testing
1281 whether the speed is < 0.
1286 After Motor. The flight software counts each time the
1287 rocket starts accelerating (presumably due to a motor or
1288 motors igniting). Use this value to count ignitions for
1289 multi-staged or multi-airstart launches.
1294 Delay. This value doesn't perform any checks, instead it
1295 inserts a delay between the time when the other
1296 parameters become true and when the pyro channel is
1302 Flight State. The flight software tracks the flight
1303 through a sequence of states:
1307 Boost. The motor has lit and the rocket is
1308 accelerating upwards.
1313 Fast. The motor has burned out and the rocket is
1314 descellerating, but it is going faster than 200m/s.
1319 Coast. The rocket is still moving upwards and
1320 decelerating, but the speed is less than 200m/s.
1325 Drogue. The rocket has reached apogee and is heading
1326 back down, but is above the configured Main
1332 Main. The rocket is still descending, and is below
1338 Landed. The rocket is no longer moving.
1344 You can select a state to limit when the pyro channel
1345 may activate; note that the check is based on when the
1346 rocket transitions <emphasis>into</emphasis> the state, and so checking for
1347 “greater than Boost” means that the rocket is currently
1348 in boost or some later state.
1351 When a motor burns out, the rocket enters either Fast or
1352 Coast state (depending on how fast it is moving). If the
1353 computer detects upwards acceleration again, it will
1354 move back to Boost state.
1363 <title>AltosUI</title>
1367 <imagedata fileref="altosui.png" width="5.5in"/>
1372 The AltosUI program provides a graphical user interface for
1373 interacting with the Altus Metrum product family. AltosUI can
1374 monitor telemetry data, configure devices and many other
1375 tasks. The primary interface window provides a selection of
1376 buttons, one for each major activity in the system. This chapter
1377 is split into sections, each of which documents one of the tasks
1378 provided from the top-level toolbar.
1381 <title>Monitor Flight</title>
1382 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
1384 Selecting this item brings up a dialog box listing all of the
1385 connected TeleDongle devices. When you choose one of these,
1386 AltosUI will create a window to display telemetry data as
1387 received by the selected TeleDongle device.
1392 <imagedata fileref="device-selection.png" width="3.5in"/>
1397 All telemetry data received are automatically recorded in
1398 suitable log files. The name of the files includes the current
1399 date and rocket serial and flight numbers.
1402 The radio frequency being monitored by the TeleDongle device is
1403 displayed at the top of the window. You can configure the
1404 frequency by clicking on the frequency box and selecting the desired
1405 frequency. AltosUI remembers the last frequency selected for each
1406 TeleDongle and selects that automatically the next time you use
1410 Below the TeleDongle frequency selector, the window contains a few
1411 significant pieces of information about the altimeter providing
1412 the telemetry data stream:
1416 <para>The configured call-sign</para>
1419 <para>The device serial number</para>
1422 <para>The flight number. Each altimeter remembers how many
1428 The rocket flight state. Each flight passes through several
1429 states including Pad, Boost, Fast, Coast, Drogue, Main and
1435 The Received Signal Strength Indicator value. This lets
1436 you know how strong a signal TeleDongle is receiving. The
1437 radio inside TeleDongle operates down to about -99dBm;
1438 weaker signals may not be receivable. The packet link uses
1439 error detection and correction techniques which prevent
1440 incorrect data from being reported.
1445 The age of the displayed data, in seconds since the last
1446 successfully received telemetry packet. In normal operation
1447 this will stay in the low single digits. If the number starts
1448 counting up, then you are no longer receiving data over the radio
1449 link from the flight computer.
1454 Finally, the largest portion of the window contains a set of
1455 tabs, each of which contain some information about the rocket.
1456 They're arranged in 'flight order' so that as the flight
1457 progresses, the selected tab automatically switches to display
1458 data relevant to the current state of the flight. You can select
1459 other tabs at any time. The final 'table' tab displays all of
1460 the raw telemetry values in one place in a spreadsheet-like format.
1463 <title>Launch Pad</title>
1467 <imagedata fileref="launch-pad.png" width="5.5in"/>
1472 The 'Launch Pad' tab shows information used to decide when the
1473 rocket is ready for flight. The first elements include red/green
1474 indicators, if any of these is red, you'll want to evaluate
1475 whether the rocket is ready to launch:
1478 <term>Battery Voltage</term>
1481 This indicates whether the Li-Po battery powering the
1482 flight computer has sufficient charge to last for
1483 the duration of the flight. A value of more than
1484 3.8V is required for a 'GO' status.
1489 <term>Apogee Igniter Voltage</term>
1492 This indicates whether the apogee
1493 igniter has continuity. If the igniter has a low
1494 resistance, then the voltage measured here will be close
1495 to the Li-Po battery voltage. A value greater than 3.2V is
1496 required for a 'GO' status.
1501 <term>Main Igniter Voltage</term>
1504 This indicates whether the main
1505 igniter has continuity. If the igniter has a low
1506 resistance, then the voltage measured here will be close
1507 to the Li-Po battery voltage. A value greater than 3.2V is
1508 required for a 'GO' status.
1513 <term>On-board Data Logging</term>
1516 This indicates whether there is
1517 space remaining on-board to store flight data for the
1518 upcoming flight. If you've downloaded data, but failed
1519 to erase flights, there may not be any space
1520 left. Most of our flight computers can store multiple
1521 flights, depending on the configured maximum flight log
1522 size. TeleMini v1.0 stores only a single flight, so it
1524 downloaded and erased after each flight to capture
1525 data. This only affects on-board flight logging; the
1526 altimeter will still transmit telemetry and fire
1527 ejection charges at the proper times even if the flight
1528 data storage is full.
1533 <term>GPS Locked</term>
1536 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
1537 currently able to compute position information. GPS requires
1538 at least 4 satellites to compute an accurate position.
1543 <term>GPS Ready</term>
1546 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
1547 10 consecutive positions without losing lock. This ensures
1548 that the GPS receiver has reliable reception from the
1556 The Launchpad tab also shows the computed launch pad position
1557 and altitude, averaging many reported positions to improve the
1558 accuracy of the fix.
1562 <title>Ascent</title>
1566 <imagedata fileref="ascent.png" width="5.5in"/>
1571 This tab is shown during Boost, Fast and Coast
1572 phases. The information displayed here helps monitor the
1573 rocket as it heads towards apogee.
1576 The height, speed and acceleration are shown along with the
1577 maximum values for each of them. This allows you to quickly
1578 answer the most commonly asked questions you'll hear during
1582 The current latitude and longitude reported by the GPS are
1583 also shown. Note that under high acceleration, these values
1584 may not get updated as the GPS receiver loses position
1585 fix. Once the rocket starts coasting, the receiver should
1586 start reporting position again.
1589 Finally, the current igniter voltages are reported as in the
1590 Launch Pad tab. This can help diagnose deployment failures
1591 caused by wiring which comes loose under high acceleration.
1595 <title>Descent</title>
1599 <imagedata fileref="descent.png" width="5.5in"/>
1604 Once the rocket has reached apogee and (we hope) activated the
1605 apogee charge, attention switches to tracking the rocket on
1606 the way back to the ground, and for dual-deploy flights,
1607 waiting for the main charge to fire.
1610 To monitor whether the apogee charge operated correctly, the
1611 current descent rate is reported along with the current
1612 height. Good descent rates vary based on the choice of recovery
1613 components, but generally range from 15-30m/s on drogue and should
1614 be below 10m/s when under the main parachute in a dual-deploy flight.
1617 With GPS-equipped flight computers, you can locate the rocket in the
1618 sky using the elevation and bearing information to figure
1619 out where to look. Elevation is in degrees above the
1620 horizon. Bearing is reported in degrees relative to true
1621 north. Range can help figure out how big the rocket will
1622 appear. Ground Distance shows how far it is to a point
1623 directly under the rocket and can help figure out where the
1624 rocket is likely to land. Note that all of these values are
1625 relative to the pad location. If the elevation is near 90°,
1626 the rocket is over the pad, not over you.
1629 Finally, the igniter voltages are reported in this tab as
1630 well, both to monitor the main charge as well as to see what
1631 the status of the apogee charge is. Note that some commercial
1632 e-matches are designed to retain continuity even after being
1633 fired, and will continue to show as green or return from red to
1638 <title>Landed</title>
1642 <imagedata fileref="landed.png" width="5.5in"/>
1647 Once the rocket is on the ground, attention switches to
1648 recovery. While the radio signal is often lost once the
1649 rocket is on the ground, the last reported GPS position is
1650 generally within a short distance of the actual landing location.
1653 The last reported GPS position is reported both by
1654 latitude and longitude as well as a bearing and distance from
1655 the launch pad. The distance should give you a good idea of
1656 whether to walk or hitch a ride. Take the reported
1657 latitude and longitude and enter them into your hand-held GPS
1658 unit and have that compute a track to the landing location.
1661 Our flight computers will continue to transmit RDF
1662 tones after landing, allowing you to locate the rocket by
1663 following the radio signal if necessary. You may need to get
1664 away from the clutter of the flight line, or even get up on
1665 a hill (or your neighbor's RV roof) to receive the RDF signal.
1668 The maximum height, speed and acceleration reported
1669 during the flight are displayed for your admiring observers.
1670 The accuracy of these immediate values depends on the quality
1671 of your radio link and how many packets were received.
1672 Recovering the on-board data after flight may yield
1673 more precise results.
1676 To get more detailed information about the flight, you can
1677 click on the 'Graph Flight' button which will bring up a
1678 graph window for the current flight.
1682 <title>Table</title>
1686 <imagedata fileref="table.png" width="5.5in"/>
1691 The table view shows all of the data available from the
1692 flight computer. Probably the most useful data on
1693 this tab is the detailed GPS information, which includes
1694 horizontal dilution of precision information, and
1695 information about the signal being received from the satellites.
1699 <title>Site Map</title>
1703 <imagedata fileref="site-map.png" width="5.5in"/>
1708 When the TeleMetrum has a GPS fix, the Site Map tab will map
1709 the rocket's position to make it easier for you to locate the
1710 rocket, both while it is in the air, and when it has landed. The
1711 rocket's state is indicated by color: white for pad, red for
1712 boost, pink for fast, yellow for coast, light blue for drogue,
1713 dark blue for main, and black for landed.
1716 The map's scale is approximately 3m (10ft) per pixel. The map
1717 can be dragged using the left mouse button. The map will attempt
1718 to keep the rocket roughly centered while data is being received.
1721 Images are fetched automatically via the Google Maps Static API,
1722 and cached on disk for reuse. If map images cannot be downloaded,
1723 the rocket's path will be traced on a dark gray background
1727 You can pre-load images for your favorite launch sites
1728 before you leave home; check out the 'Preload Maps' section below.
1733 <title>Save Flight Data</title>
1735 The altimeter records flight data to its internal flash memory.
1736 TeleMetrum data is recorded at a much higher rate than the telemetry
1737 system can handle, and is not subject to radio drop-outs. As
1738 such, it provides a more complete and precise record of the
1739 flight. The 'Save Flight Data' button allows you to read the
1740 flash memory and write it to disk.
1743 Clicking on the 'Save Flight Data' button brings up a list of
1744 connected flight computers and TeleDongle devices. If you select a
1745 flight computer, the flight data will be downloaded from that
1746 device directly. If you select a TeleDongle device, flight data
1747 will be downloaded from a flight computer over radio link via the
1748 specified TeleDongle. See the chapter on Controlling An Altimeter
1749 Over The Radio Link for more information.
1752 After the device has been selected, a dialog showing the
1753 flight data saved in the device will be shown allowing you to
1754 select which flights to download and which to delete. With
1755 version 0.9 or newer firmware, you must erase flights in order
1756 for the space they consume to be reused by another
1757 flight. This prevents accidentally losing flight data
1758 if you neglect to download data before flying again. Note that
1759 if there is no more space available in the device, then no
1760 data will be recorded during the next flight.
1763 The file name for each flight log is computed automatically
1764 from the recorded flight date, altimeter serial number and
1765 flight number information.
1769 <title>Replay Flight</title>
1771 Select this button and you are prompted to select a flight
1772 record file, either a .telem file recording telemetry data or a
1773 .eeprom file containing flight data saved from the altimeter
1777 Once a flight record is selected, the flight monitor interface
1778 is displayed and the flight is re-enacted in real time. Check
1779 the Monitor Flight chapter above to learn how this window operates.
1783 <title>Graph Data</title>
1785 Select this button and you are prompted to select a flight
1786 record file, either a .telem file recording telemetry data or a
1787 .eeprom file containing flight data saved from
1791 Note that telemetry files will generally produce poor graphs
1792 due to the lower sampling rate and missed telemetry packets.
1793 Use saved flight data in .eeprom files for graphing where possible.
1796 Once a flight record is selected, a window with multiple tabs is
1800 <title>Flight Graph</title>
1804 <imagedata fileref="graph.png" width="5.5in" scalefit="1"/>
1809 By default, the graph contains acceleration (blue),
1810 velocity (green) and altitude (red).
1813 The graph can be zoomed into a particular area by clicking and
1814 dragging down and to the right. Once zoomed, the graph can be
1815 reset by clicking and dragging up and to the left. Holding down
1816 control and clicking and dragging allows the graph to be panned.
1817 The right mouse button causes a pop-up menu to be displayed, giving
1818 you the option save or print the plot.
1822 <title>Configure Graph</title>
1826 <imagedata fileref="graph-configure.png" width="5.5in" scalefit="1"/>
1831 This selects which graph elements to show, and, at the
1832 very bottom, lets you switch between metric and
1837 <title>Flight Statistics</title>
1841 <imagedata fileref="graph-stats.png" width="5.5in" scalefit="1"/>
1846 Shows overall data computed from the flight.
1854 <imagedata fileref="graph-map.png" width="5.5in" scalefit="1"/>
1859 Shows a satellite image of the flight area overlaid
1860 with the path of the flight. The red concentric
1861 circles mark the launch pad, the black concentric
1862 circles mark the landing location.
1867 <title>Export Data</title>
1869 This tool takes the raw data files and makes them available for
1870 external analysis. When you select this button, you are prompted to
1871 select a flight data file, which can be either a .eeprom or .telem.
1872 The .eeprom files contain higher resolution and more continuous data,
1873 while .telem files contain receiver signal strength information.
1874 Next, a second dialog appears which is used to select
1875 where to write the resulting file. It has a selector to choose
1876 between CSV and KML file formats.
1879 <title>Comma Separated Value Format</title>
1881 This is a text file containing the data in a form suitable for
1882 import into a spreadsheet or other external data analysis
1883 tool. The first few lines of the file contain the version and
1884 configuration information from the altimeter, then
1885 there is a single header line which labels all of the
1886 fields. All of these lines start with a '#' character which
1887 many tools can be configured to skip over.
1890 The remaining lines of the file contain the data, with each
1891 field separated by a comma and at least one space. All of
1892 the sensor values are converted to standard units, with the
1893 barometric data reported in both pressure, altitude and
1894 height above pad units.
1898 <title>Keyhole Markup Language (for Google Earth)</title>
1900 This is the format used by Google Earth to provide an overlay
1901 within that application. With this, you can use Google Earth to
1902 see the whole flight path in 3D.
1907 <title>Configure Altimeter</title>
1911 <imagedata fileref="configure-altimeter.png" width="3in" scalefit="1"/>
1916 Select this button and then select either an altimeter or
1917 TeleDongle Device from the list provided. Selecting a TeleDongle
1918 device will use the radio link to configure a remote altimeter.
1921 The first few lines of the dialog provide information about the
1922 connected device, including the product name,
1923 software version and hardware serial number. Below that are the
1924 individual configuration entries.
1927 At the bottom of the dialog, there are four buttons:
1934 This writes any changes to the
1935 configuration parameter block in flash memory. If you don't
1936 press this button, any changes you make will be lost.
1944 This resets the dialog to the most recently saved values,
1945 erasing any changes you have made.
1953 This reboots the device. Use this to
1954 switch from idle to pad mode by rebooting once the rocket is
1955 oriented for flight, or to confirm changes you think you saved
1964 This closes the dialog. Any unsaved changes will be
1971 The rest of the dialog contains the parameters to be configured.
1974 <title>Main Deploy Altitude</title>
1976 This sets the altitude (above the recorded pad altitude) at
1977 which the 'main' igniter will fire. The drop-down menu shows
1978 some common values, but you can edit the text directly and
1979 choose whatever you like. If the apogee charge fires below
1980 this altitude, then the main charge will fire two seconds
1981 after the apogee charge fires.
1985 <title>Apogee Delay</title>
1987 When flying redundant electronics, it's often important to
1988 ensure that multiple apogee charges don't fire at precisely
1989 the same time, as that can over pressurize the apogee deployment
1990 bay and cause a structural failure of the air-frame. The Apogee
1991 Delay parameter tells the flight computer to fire the apogee
1992 charge a certain number of seconds after apogee has been
1997 <title>Radio Frequency</title>
1999 This configures which of the frequencies to use for both
2000 telemetry and packet command mode. Note that if you set this
2001 value via packet command mode, the TeleDongle frequency will
2002 also be automatically reconfigured to match so that
2003 communication will continue afterwards.
2007 <title>RF Calibration</title>
2009 The radios in every Altus Metrum device are calibrated at the
2010 factory to ensure that they transmit and receive on the
2011 specified frequency. If you need to you can adjust the calibration
2012 by changing this value. Do not do this without understanding what
2013 the value means, read the appendix on calibration and/or the source
2014 code for more information. To change a TeleDongle's calibration,
2015 you must reprogram the unit completely.
2019 <title>Telemetry/RDF/APRS Enable</title>
2021 Enables the radio for transmission during flight. When
2022 disabled, the radio will not transmit anything during flight
2027 <title>APRS Interval</title>
2029 How often to transmit GPS information via APRS. This option
2030 is available on TeleMetrum v2 and TeleMega
2031 boards. TeleMetrum v1 boards cannot transmit APRS
2032 packets. Note that a single APRS packet takes nearly a full
2033 second to transmit, so enabling this option will prevent
2034 sending any other telemetry during that time.
2038 <title>Callsign</title>
2040 This sets the call sign included in each telemetry packet. Set this
2041 as needed to conform to your local radio regulations.
2045 <title>Maximum Flight Log Size</title>
2047 This sets the space (in kilobytes) allocated for each flight
2048 log. The available space will be divided into chunks of this
2049 size. A smaller value will allow more flights to be stored,
2050 a larger value will record data from longer flights.
2054 <title>Ignite Mode</title>
2056 TeleMetrum and TeleMini provide two igniter channels as they
2057 were originally designed as dual-deploy flight
2058 computers. This configuration parameter allows the two
2059 channels to be used in different configurations.
2063 <term>Dual Deploy</term>
2066 This is the usual mode of operation; the
2067 'apogee' channel is fired at apogee and the 'main'
2068 channel at the height above ground specified by the
2069 'Main Deploy Altitude' during descent.
2074 <term>Redundant Apogee</term>
2077 This fires both channels at
2078 apogee, the 'apogee' channel first followed after a two second
2079 delay by the 'main' channel.
2084 <term>Redundant Main</term>
2087 This fires both channels at the
2088 height above ground specified by the Main Deploy
2089 Altitude setting during descent. The 'apogee'
2090 channel is fired first, followed after a two second
2091 delay by the 'main' channel.
2098 <title>Pad Orientation</title>
2100 Because they include accelerometers, TeleMetrum and
2101 TeleMega are sensitive to the orientation of the board. By
2102 default, they expect the antenna end to point forward. This
2103 parameter allows that default to be changed, permitting the
2104 board to be mounted with the antenna pointing aft instead.
2108 <term>Antenna Up</term>
2111 In this mode, the antenna end of the
2112 flight computer must point forward, in line with the
2113 expected flight path.
2118 <term>Antenna Down</term>
2121 In this mode, the antenna end of the
2122 flight computer must point aft, in line with the
2123 expected flight path.
2130 <title>Configure Pyro Channels</title>
2134 <imagedata fileref="configure-pyro.png" width="6in" scalefit="1"/>
2139 This opens a separate window to configure the additional
2140 pyro channels available on TeleMega. One column is
2141 presented for each channel. Each row represents a single
2142 parameter, if enabled the parameter must meet the specified
2143 test for the pyro channel to be fired. See the Pyro Channels
2144 section in the System Operation chapter above for a
2145 description of these parameters.
2148 Select conditions and set the related value; the pyro
2149 channel will be activated when <emphasis>all</emphasis> of the
2150 conditions are met. Each pyro channel has a separate set of
2151 configuration values, so you can use different values for
2152 the same condition with different channels.
2155 Once you have selected the appropriate configuration for all
2156 of the necessary pyro channels, you can save the pyro
2157 configuration along with the rest of the flight computer
2158 configuration by pressing the 'Save' button in the main
2159 Configure Flight Computer window.
2164 <title>Configure AltosUI</title>
2168 <imagedata fileref="configure-altosui.png" width="2.5in" scalefit="1"/>
2173 This button presents a dialog so that you can configure the AltosUI global settings.
2176 <title>Voice Settings</title>
2178 AltosUI provides voice announcements during flight so that you
2179 can keep your eyes on the sky and still get information about
2180 the current flight status. However, sometimes you don't want
2187 <para>Turns all voice announcements on and off</para>
2191 <term>Test Voice</term>
2194 Plays a short message allowing you to verify
2195 that the audio system is working and the volume settings
2203 <title>Log Directory</title>
2205 AltosUI logs all telemetry data and saves all TeleMetrum flash
2206 data to this directory. This directory is also used as the
2207 staring point when selecting data files for display or export.
2210 Click on the directory name to bring up a directory choosing
2211 dialog, select a new directory and click 'Select Directory' to
2212 change where AltosUI reads and writes data files.
2216 <title>Callsign</title>
2218 This value is transmitted in each command packet sent from
2219 TeleDongle and received from an altimeter. It is not used in
2220 telemetry mode, as the callsign configured in the altimeter board
2221 is included in all telemetry packets. Configure this
2222 with the AltosUI operators call sign as needed to comply with
2223 your local radio regulations.
2226 Note that to successfully command a flight computer over the radio
2227 (to configure the altimeter, monitor idle, or fire pyro charges),
2228 the callsign configured here must exactly match the callsign
2229 configured in the flight computer. This matching is case
2234 <title>Imperial Units</title>
2236 This switches between metric units (meters) and imperial
2237 units (feet and miles). This affects the display of values
2238 use during flight monitoring, configuration, data graphing
2239 and all of the voice announcements. It does not change the
2240 units used when exporting to CSV files, those are always
2241 produced in metric units.
2245 <title>Font Size</title>
2247 Selects the set of fonts used in the flight monitor
2248 window. Choose between the small, medium and large sets.
2252 <title>Serial Debug</title>
2254 This causes all communication with a connected device to be
2255 dumped to the console from which AltosUI was started. If
2256 you've started it from an icon or menu entry, the output
2257 will simply be discarded. This mode can be useful to debug
2258 various serial communication issues.
2262 <title>Manage Frequencies</title>
2264 This brings up a dialog where you can configure the set of
2265 frequencies shown in the various frequency menus. You can
2266 add as many as you like, or even reconfigure the default
2267 set. Changing this list does not affect the frequency
2268 settings of any devices, it only changes the set of
2269 frequencies shown in the menus.
2274 <title>Configure Groundstation</title>
2278 <imagedata fileref="configure-groundstation.png" width="3in" scalefit="1"/>
2283 Select this button and then select a TeleDongle Device from the list provided.
2286 The first few lines of the dialog provide information about the
2287 connected device, including the product name,
2288 software version and hardware serial number. Below that are the
2289 individual configuration entries.
2292 Note that the TeleDongle itself doesn't save any configuration
2293 data, the settings here are recorded on the local machine in
2294 the Java preferences database. Moving the TeleDongle to
2295 another machine, or using a different user account on the same
2296 machine will cause settings made here to have no effect.
2299 At the bottom of the dialog, there are three buttons:
2306 This writes any changes to the
2307 local Java preferences file. If you don't
2308 press this button, any changes you make will be lost.
2316 This resets the dialog to the most recently saved values,
2317 erasing any changes you have made.
2325 This closes the dialog. Any unsaved changes will be
2332 The rest of the dialog contains the parameters to be configured.
2335 <title>Frequency</title>
2337 This configures the frequency to use for both telemetry and
2338 packet command mode. Set this before starting any operation
2339 involving packet command mode so that it will use the right
2340 frequency. Telemetry monitoring mode also provides a menu to
2341 change the frequency, and that menu also sets the same Java
2342 preference value used here.
2346 <title>Radio Calibration</title>
2348 The radios in every Altus Metrum device are calibrated at the
2349 factory to ensure that they transmit and receive on the
2350 specified frequency. To change a TeleDongle's calibration,
2351 you must reprogram the unit completely, so this entry simply
2352 shows the current value and doesn't allow any changes.
2357 <title>Flash Image</title>
2359 This reprograms Altus Metrum devices with new
2360 firmware. TeleMetrum v1.x, TeleDongle, TeleMini and TeleBT are
2361 all reprogrammed by using another similar unit as a
2362 programming dongle (pair programming). TeleMega, TeleMetrum v2
2363 and EasyMini are all programmed directly over their USB ports
2364 (self programming). Please read the directions for flashing
2365 devices in the Updating Device Firmware chapter below.
2369 <title>Fire Igniter</title>
2373 <imagedata fileref="fire-igniter.png" width="1in" scalefit="1"/>
2378 This activates the igniter circuits in the flight computer to help
2379 test recovery systems deployment. Because this command can operate
2380 over the Packet Command Link, you can prepare the rocket as
2381 for flight and then test the recovery system without needing
2382 to snake wires inside the air-frame.
2385 Selecting the 'Fire Igniter' button brings up the usual device
2386 selection dialog. Pick the desired device. This brings up another
2387 window which shows the current continuity test status for both
2388 apogee and main charges.
2391 Next, select the desired igniter to fire. This will enable the
2395 Select the 'Arm' button. This enables the 'Fire' button. The
2396 word 'Arm' is replaced by a countdown timer indicating that
2397 you have 10 seconds to press the 'Fire' button or the system
2398 will deactivate, at which point you start over again at
2399 selecting the desired igniter.
2403 <title>Scan Channels</title>
2407 <imagedata fileref="scan-channels.png" width="2.75in" scalefit="1"/>
2412 This listens for telemetry packets on all of the configured
2413 frequencies, displaying information about each device it
2414 receives a packet from. You can select which of the three
2415 telemetry formats should be tried; by default, it only listens
2416 for the standard telemetry packets used in v1.0 and later
2421 <title>Load Maps</title>
2425 <imagedata fileref="load-maps.png" width="5.5in" scalefit="1"/>
2430 Before heading out to a new launch site, you can use this to
2431 load satellite images in case you don't have internet
2432 connectivity at the site. This loads a fairly large area
2433 around the launch site, which should cover any flight you're likely to make.
2436 There's a drop-down menu of launch sites we know about; if
2437 your favorites aren't there, please let us know the lat/lon
2438 and name of the site. The contents of this list are actually
2439 downloaded from our server at run-time, so as new sites are sent
2440 in, they'll get automatically added to this list.
2443 If the launch site isn't in the list, you can manually enter the lat/lon values
2446 Clicking the 'Load Map' button will fetch images from Google
2447 Maps; note that Google limits how many images you can fetch at
2448 once, so if you load more than one launch site, you may get
2449 some gray areas in the map which indicate that Google is tired
2450 of sending data to you. Try again later.
2454 <title>Monitor Idle</title>
2456 This brings up a dialog similar to the Monitor Flight UI,
2457 except it works with the altimeter in “idle” mode by sending
2458 query commands to discover the current state rather than
2459 listening for telemetry packets. Because this uses command
2460 mode, it needs to have the TeleDongle and flight computer
2461 callsigns match exactly. If you can receive telemetry, but
2462 cannot manage to run Monitor Idle, then it's very likely that
2463 your callsigns are different in some way.
2468 <title>AltosDroid</title>
2470 AltosDroid provides the same flight monitoring capabilities as
2471 AltosUI, but runs on Android devices and is designed to connect
2472 to a TeleBT receiver over Bluetooth™. AltosDroid monitors
2473 telemetry data, logging it to internal storage in the Android
2474 device, and presents that data in a UI the same way the 'Monitor
2475 Flight' window does in AltosUI.
2478 This manual will explain how to configure AltosDroid, connect
2479 to TeleBT, operate the flight monitoring interface and describe
2480 what the displayed data means.
2483 <title>Installing AltosDroid</title>
2485 AltosDroid is available from the Google Play store. To install
2486 it on your Android device, open the Google Play Store
2487 application and search for “altosdroid”. Make sure you don't
2488 have a space between “altos” and “droid” or you probably won't
2489 find what you want. That should bring you to the right page
2490 from which you can download and install the application.
2494 <title>Connecting to TeleBT</title>
2496 Press the Android 'Menu' button or soft-key to see the
2497 configuration options available. Select the 'Connect a device'
2498 option and then the 'Scan for devices' entry at the bottom to
2499 look for your TeleBT device. Select your device, and when it
2500 asks for the code, enter '1234'.
2503 Subsequent connections will not require you to enter that
2504 code, and your 'paired' device will appear in the list without
2509 <title>Configuring AltosDroid</title>
2511 The only configuration option available for AltosDroid is
2512 which frequency to listen on. Press the Android 'Menu' button
2513 or soft-key and pick the 'Select radio frequency' entry. That
2514 brings up a menu of pre-set radio frequencies; pick the one
2515 which matches your altimeter.
2519 <title>AltosDroid Flight Monitoring</title>
2521 AltosDroid is designed to mimic the AltosUI flight monitoring
2522 display, providing separate tabs for each stage of your rocket
2523 flight along with a tab containing a map of the local area
2524 with icons marking the current location of the altimeter and
2530 The 'Launch Pad' tab shows information used to decide when the
2531 rocket is ready for flight. The first elements include red/green
2532 indicators, if any of these is red, you'll want to evaluate
2533 whether the rocket is ready to launch:
2536 <term>Battery Voltage</term>
2539 This indicates whether the Li-Po battery
2540 powering the TeleMetrum has sufficient charge to last for
2541 the duration of the flight. A value of more than
2542 3.8V is required for a 'GO' status.
2547 <term>Apogee Igniter Voltage</term>
2550 This indicates whether the apogee
2551 igniter has continuity. If the igniter has a low
2552 resistance, then the voltage measured here will be close
2553 to the Li-Po battery voltage. A value greater than 3.2V is
2554 required for a 'GO' status.
2559 <term>Main Igniter Voltage</term>
2562 This indicates whether the main
2563 igniter has continuity. If the igniter has a low
2564 resistance, then the voltage measured here will be close
2565 to the Li-Po battery voltage. A value greater than 3.2V is
2566 required for a 'GO' status.
2571 <term>On-board Data Logging</term>
2574 This indicates whether there is
2575 space remaining on-board to store flight data for the
2576 upcoming flight. If you've downloaded data, but failed
2577 to erase flights, there may not be any space
2578 left. TeleMetrum can store multiple flights, depending
2579 on the configured maximum flight log size. TeleMini
2580 stores only a single flight, so it will need to be
2581 downloaded and erased after each flight to capture
2582 data. This only affects on-board flight logging; the
2583 altimeter will still transmit telemetry and fire
2584 ejection charges at the proper times.
2589 <term>GPS Locked</term>
2592 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
2593 currently able to compute position information. GPS requires
2594 at least 4 satellites to compute an accurate position.
2599 <term>GPS Ready</term>
2602 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
2603 10 consecutive positions without losing lock. This ensures
2604 that the GPS receiver has reliable reception from the
2612 The Launchpad tab also shows the computed launch pad position
2613 and altitude, averaging many reported positions to improve the
2614 accuracy of the fix.
2619 <title>Downloading Flight Logs</title>
2621 AltosDroid always saves every bit of telemetry data it
2622 receives. To download that to a computer for use with AltosUI,
2623 simply remove the SD card from your Android device, or connect
2624 your device to your computer's USB port and browse the files
2625 on that device. You will find '.telem' files in the TeleMetrum
2626 directory that will work with AltosUI directly.
2631 <title>Using Altus Metrum Products</title>
2633 <title>Being Legal</title>
2635 First off, in the US, you need an <ulink url="http://www.altusmetrum.org/Radio/">amateur radio license</ulink> or
2636 other authorization to legally operate the radio transmitters that are part
2641 <title>In the Rocket</title>
2643 In the rocket itself, you just need a flight computer and
2644 a single-cell, 3.7 volt nominal Li-Po rechargeable battery. An
2645 850mAh battery weighs less than a 9V alkaline battery, and will
2646 run a TeleMetrum or TeleMega for hours.
2647 A 110mAh battery weighs less than a triple A battery and is a good
2648 choice for use with TeleMini.
2651 By default, we ship flight computers with a simple wire antenna.
2652 If your electronics bay or the air-frame it resides within is made
2653 of carbon fiber, which is opaque to RF signals, you may prefer to
2654 install an SMA connector so that you can run a coaxial cable to an
2655 antenna mounted elsewhere in the rocket. However, note that the
2656 GPS antenna is fixed on all current products, so you really want
2657 to install the flight computer in a bay made of RF-transparent
2658 materials if at all possible.
2662 <title>On the Ground</title>
2664 To receive the data stream from the rocket, you need an antenna and short
2665 feed-line connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. If possible, use an SMA to BNC
2666 adapter instead of feedline between the antenna feedpoint and
2667 TeleDongle, as this will give you the best performance. The
2668 TeleDongle in turn plugs directly into the USB port on a notebook
2669 computer. Because TeleDongle looks like a simple serial port, your computer
2670 does not require special device drivers... just plug it in.
2673 The GUI tool, AltosUI, is written in Java and runs across
2674 Linux, Mac OS and Windows. There's also a suite of C tools
2675 for Linux which can perform most of the same tasks.
2678 Alternatively, a TeleBT attached with an SMA to BNC adapter at the
2679 feed point of a hand-held yagi used in conjunction with an Android
2680 device running AltosDroid makes an outstanding ground station.
2683 After the flight, you can use the radio link to extract the more detailed data
2684 logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
2685 TeleMetrum board directly. Pulling out the data without having to open up
2686 the rocket is pretty cool! A USB cable is also how you charge the Li-Po
2687 battery, so you'll want one of those anyway... the same cable used by lots
2688 of digital cameras and other modern electronic stuff will work fine.
2691 If your rocket lands out of sight, you may enjoy having a hand-held
2692 GPS receiver, so that you can put in a way-point for the last
2693 reported rocket position before touch-down. This makes looking for
2694 your rocket a lot like Geo-Caching... just go to the way-point and
2695 look around starting from there. AltosDroid on an Android device
2696 with GPS receiver works great for this, too!
2699 You may also enjoy having a ham radio “HT” that covers the 70cm band... you
2700 can use that with your antenna to direction-find the rocket on the ground
2701 the same way you can use a Walston or Beeline tracker. This can be handy
2702 if the rocket is hiding in sage brush or a tree, or if the last GPS position
2703 doesn't get you close enough because the rocket dropped into a canyon, or
2704 the wind is blowing it across a dry lake bed, or something like that... Keith
2705 currently uses a Yaesu VX-7R, Bdale has a Baofung UV-5R
2706 which isn't as nice, but was a whole lot cheaper.
2709 So, to recap, on the ground the hardware you'll need includes:
2710 <orderedlist inheritnum='inherit' numeration='arabic'>
2713 an antenna and feed-line or adapter
2728 optionally, a hand-held GPS receiver
2733 optionally, an HT or receiver covering 435 MHz
2739 The best hand-held commercial directional antennas we've found for radio
2740 direction finding rockets are from
2741 <ulink url="http://www.arrowantennas.com/" >
2744 The 440-3 and 440-5 are both good choices for finding a
2745 TeleMetrum- or TeleMini- equipped rocket when used with a suitable
2746 70cm HT. TeleDongle and an SMA to BNC adapter fit perfectly
2747 between the driven element and reflector of Arrow antennas.
2751 <title>Data Analysis</title>
2753 Our software makes it easy to log the data from each flight, both the
2754 telemetry received during the flight itself, and the more
2755 complete data log recorded in the flash memory on the altimeter
2756 board. Once this data is on your computer, our post-flight tools make it
2757 easy to quickly get to the numbers everyone wants, like apogee altitude,
2758 max acceleration, and max velocity. You can also generate and view a
2759 standard set of plots showing the altitude, acceleration, and
2760 velocity of the rocket during flight. And you can even export a TeleMetrum data file
2761 usable with Google Maps and Google Earth for visualizing the flight path
2762 in two or three dimensions!
2765 Our ultimate goal is to emit a set of files for each flight that can be
2766 published as a web page per flight, or just viewed on your local disk with
2771 <title>Future Plans</title>
2773 We've designed a simple GPS based radio tracker called TeleGPS.
2774 If all goes well, we hope to introduce this in the first
2778 We have designed and prototyped several “companion boards” that
2779 can attach to the companion connector on TeleMetrum and TeleMega
2780 flight computers to collect more data, provide more pyro channels,
2781 and so forth. We do not yet know if or when any of these boards
2782 will be produced in enough quantity to sell. If you have specific
2783 interests for data collection or control of events in your rockets
2784 beyond the capabilities of our existing productions, please let
2788 Because all of our work is open, both the hardware designs and the
2789 software, if you have some great idea for an addition to the current
2790 Altus Metrum family, feel free to dive in and help! Or let us know
2791 what you'd like to see that we aren't already working on, and maybe
2792 we'll get excited about it too...
2796 <ulink url="http://altusmetrum.org/">web site</ulink> for more news
2797 and information as our family of products evolves!
2802 <title>Altimeter Installation Recommendations</title>
2804 Building high-power rockets that fly safely is hard enough. Mix
2805 in some sophisticated electronics and a bunch of radio energy
2806 and some creativity and/or compromise may be required. This chapter
2807 contains some suggestions about how to install Altus Metrum
2808 products into a rocket air-frame, including how to safely and
2809 reliably mix a variety of electronics into the same air-frame.
2812 <title>Mounting the Altimeter</title>
2814 The first consideration is to ensure that the altimeter is
2815 securely fastened to the air-frame. For most of our products, we
2816 prefer nylon standoffs and nylon screws; they're good to at least 50G
2817 and cannot cause any electrical issues on the board. Metal screws
2818 and standoffs are fine, too, just be careful to avoid electrical
2819 shorts! For TeleMini v1.0, we usually cut small pieces of 1/16 inch
2821 under the screw holes, and then take 2x56 nylon screws and
2822 screw them through the TeleMini mounting holes, through the
2823 balsa and into the underlying material.
2825 <orderedlist inheritnum='inherit' numeration='arabic'>
2828 Make sure accelerometer-equipped products like TeleMetrum and
2829 TeleMega are aligned precisely along the axis of
2830 acceleration so that the accelerometer can accurately
2831 capture data during the flight.
2836 Watch for any metal touching components on the
2837 board. Shorting out connections on the bottom of the board
2838 can cause the altimeter to fail during flight.
2844 <title>Dealing with the Antenna</title>
2846 The antenna supplied is just a piece of solid, insulated,
2847 wire. If it gets damaged or broken, it can be easily
2848 replaced. It should be kept straight and not cut; bending or
2849 cutting it will change the resonant frequency and/or
2850 impedance, making it a less efficient radiator and thus
2851 reducing the range of the telemetry signal.
2854 Keeping metal away from the antenna will provide better range
2855 and a more even radiation pattern. In most rockets, it's not
2856 entirely possible to isolate the antenna from metal
2857 components; there are often bolts, all-thread and wires from other
2858 electronics to contend with. Just be aware that the more stuff
2859 like this around the antenna, the lower the range.
2862 Make sure the antenna is not inside a tube made or covered
2863 with conducting material. Carbon fiber is the most common
2864 culprit here -- CF is a good conductor and will effectively
2865 shield the antenna, dramatically reducing signal strength and
2866 range. Metallic flake paint is another effective shielding
2867 material which should be avoided around any antennas.
2870 If the ebay is large enough, it can be convenient to simply
2871 mount the altimeter at one end and stretch the antenna out
2872 inside. Taping the antenna to the sled can keep it straight
2873 under acceleration. If there are metal rods, keep the
2874 antenna as far away as possible.
2877 For a shorter ebay, it's quite practical to have the antenna
2878 run through a bulkhead and into an adjacent bay. Drill a small
2879 hole in the bulkhead, pass the antenna wire through it and
2880 then seal it up with glue or clay. We've also used acrylic
2881 tubing to create a cavity for the antenna wire. This works a
2882 bit better in that the antenna is known to stay straight and
2883 not get folded by recovery components in the bay. Angle the
2884 tubing towards the side wall of the rocket and it ends up
2885 consuming very little space.
2888 If you need to place the UHF antenna at a distance from the
2889 altimeter, you can replace the antenna with an edge-mounted
2890 SMA connector, and then run 50Ω coax from the board to the
2891 antenna. Building a remote antenna is beyond the scope of this
2896 <title>Preserving GPS Reception</title>
2898 The GPS antenna and receiver used in TeleMetrum and TeleMega is
2899 highly sensitive and normally have no trouble tracking enough
2900 satellites to provide accurate position information for
2901 recovering the rocket. However, there are many ways the GPS signal
2902 can end up attenuated, negatively affecting GPS performance.
2903 <orderedlist inheritnum='inherit' numeration='arabic'>
2906 Conductive tubing or coatings. Carbon fiber and metal
2907 tubing, or metallic paint will all dramatically attenuate the
2908 GPS signal. We've never heard of anyone successfully
2909 receiving GPS from inside these materials.
2914 Metal components near the GPS patch antenna. These will
2915 de-tune the patch antenna, changing the resonant frequency
2916 away from the L1 carrier and reduce the effectiveness of the
2917 antenna. You can place as much stuff as you like beneath the
2918 antenna as that's covered with a ground plane. But, keep
2919 wires and metal out from above the patch antenna.
2926 <title>Radio Frequency Interference</title>
2928 Any altimeter will generate RFI; the digital circuits use
2929 high-frequency clocks that spray radio interference across a
2930 wide band. Altus Metrum altimeters generate intentional radio
2931 signals as well, increasing the amount of RF energy around the board.
2934 Rocketry altimeters also use precise sensors measuring air
2935 pressure and acceleration. Tiny changes in voltage can cause
2936 these sensor readings to vary by a huge amount. When the
2937 sensors start mis-reporting data, the altimeter can either
2938 fire the igniters at the wrong time, or not fire them at all.
2941 Voltages are induced when radio frequency energy is
2942 transmitted from one circuit to another. Here are things that
2943 influence the induced voltage and current:
2948 Keep wires from different circuits apart. Moving circuits
2949 further apart will reduce RFI.
2954 Avoid parallel wires from different circuits. The longer two
2955 wires run parallel to one another, the larger the amount of
2956 transferred energy. Cross wires at right angles to reduce
2962 Twist wires from the same circuits. Two wires the same
2963 distance from the transmitter will get the same amount of
2964 induced energy which will then cancel out. Any time you have
2965 a wire pair running together, twist the pair together to
2966 even out distances and reduce RFI. For altimeters, this
2967 includes battery leads, switch hookups and igniter
2973 Avoid resonant lengths. Know what frequencies are present
2974 in the environment and avoid having wire lengths near a
2975 natural resonant length. Altus Metrum products transmit on the
2976 70cm amateur band, so you should avoid lengths that are a
2977 simple ratio of that length; essentially any multiple of ¼
2978 of the wavelength (17.5cm).
2984 <title>The Barometric Sensor</title>
2986 Altusmetrum altimeters measure altitude with a barometric
2987 sensor, essentially measuring the amount of air above the
2988 rocket to figure out how high it is. A large number of
2989 measurements are taken as the altimeter initializes itself to
2990 figure out the pad altitude. Subsequent measurements are then
2991 used to compute the height above the pad.
2994 To accurately measure atmospheric pressure, the ebay
2995 containing the altimeter must be vented outside the
2996 air-frame. The vent must be placed in a region of linear
2997 airflow, have smooth edges, and away from areas of increasing or
2998 decreasing pressure.
3001 All barometric sensors are quite sensitive to chemical damage from
3002 the products of APCP or BP combustion, so make sure the ebay is
3003 carefully sealed from any compartment which contains ejection
3008 <title>Ground Testing</title>
3010 The most important aspect of any installation is careful
3011 ground testing. Bringing an air-frame up to the LCO table which
3012 hasn't been ground tested can lead to delays or ejection
3013 charges firing on the pad, or, even worse, a recovery system
3017 Do a 'full systems' test that includes wiring up all igniters
3018 without any BP and turning on all of the electronics in flight
3019 mode. This will catch any mistakes in wiring and any residual
3020 RFI issues that might accidentally fire igniters at the wrong
3021 time. Let the air-frame sit for several minutes, checking for
3022 adequate telemetry signal strength and GPS lock. If any igniters
3023 fire unexpectedly, find and resolve the issue before loading any
3027 Ground test the ejection charges. Prepare the rocket for
3028 flight, loading ejection charges and igniters. Completely
3029 assemble the air-frame and then use the 'Fire Igniters'
3030 interface through a TeleDongle to command each charge to
3031 fire. Make sure the charge is sufficient to robustly separate
3032 the air-frame and deploy the recovery system.
3037 <title>Updating Device Firmware</title>
3039 TeleMega, TeleMetrum v2 and EasyMini are all programmed directly
3040 over their USB connectors (self programming). TeleMetrum v1, TeleMini and
3041 TeleDongle are all programmed by using another device as a
3042 programmer (pair programming). It's important to recognize which
3043 kind of devices you have before trying to reprogram them.
3046 You may wish to begin by ensuring you have current firmware images.
3047 These are distributed as part of the AltOS software bundle that
3048 also includes the AltosUI ground station program. Newer ground
3049 station versions typically work fine with older firmware versions,
3050 so you don't need to update your devices just to try out new
3051 software features. You can always download the most recent
3052 version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
3055 If you need to update the firmware on a TeleDongle, we recommend
3056 updating the altimeter first, before updating TeleDongle. However,
3057 note that TeleDongle rarely need to be updated. Any firmware version
3058 1.0.1 or later will work, version 1.2.1 may have improved receiver
3059 performance slightly.
3062 Self-programmable devices (TeleMega, TeleMetrum v2 and EasyMini)
3063 are reprogrammed by connecting them to your computer over USB
3067 Updating TeleMega, TeleMetrum v2 or EasyMini Firmware
3069 <orderedlist inheritnum='inherit' numeration='arabic'>
3072 Attach a battery and power switch to the target
3073 device. Power up the device.
3078 Using a Micro USB cable, connect the target device to your
3079 computer's USB socket.
3084 Run AltosUI, and select 'Flash Image' from the File menu.
3089 Select the target device in the Device Selection dialog.
3094 Select the image you want to flash to the device, which
3095 should have a name in the form
3096 <product>-v<product-version>-<software-version>.ihx, such
3097 as TeleMega-v1.0-1.3.0.ihx.
3102 Make sure the configuration parameters are reasonable
3103 looking. If the serial number and/or RF configuration
3104 values aren't right, you'll need to change them.
3109 Hit the 'OK' button and the software should proceed to flash
3110 the device with new firmware, showing a progress bar.
3115 Verify that the device is working by using the 'Configure
3116 Altimeter' item to check over the configuration.
3121 <title>Recovering From Self-Flashing Failure</title>
3123 If the firmware loading fails, it can leave the device
3124 unable to boot. Not to worry, you can force the device to
3125 start the boot loader instead, which will let you try to
3126 flash the device again.
3129 On each device, connecting two pins from one of the exposed
3130 connectors will force the boot loader to start, even if the
3131 regular operating system has been corrupted in some way.
3135 <term>TeleMega</term>
3138 Connect pin 6 and pin 1 of the companion connector. Pin 1
3139 can be identified by the square pad around it, and then
3140 the pins could sequentially across the board. Be very
3141 careful to <emphasis>not</emphasis> short pin 8 to
3142 anything as that is connected directly to the battery. Pin
3143 7 carries 3.3V and the board will crash if that is
3144 connected to pin 1, but shouldn't damage the board.
3149 <term>TeleMetrum v2</term>
3152 Connect pin 6 and pin 1 of the companion connector. Pin 1
3153 can be identified by the square pad around it, and then
3154 the pins could sequentially across the board. Be very
3155 careful to <emphasis>not</emphasis> short pin 8 to
3156 anything as that is connected directly to the battery. Pin
3157 7 carries 3.3V and the board will crash if that is
3158 connected to pin 1, but shouldn't damage the board.
3163 <term>EasyMini</term>
3166 Connect pin 6 and pin 1 of the debug connector, which is
3167 the six holes next to the beeper. Pin 1 can be identified
3168 by the square pad around it, and then the pins could
3169 sequentially across the board, making Pin 6 the one on the
3170 other end of the row.
3178 <title>Pair Programming</title>
3180 The big concept to understand is that you have to use a
3181 TeleMega, TeleMetrum or TeleDongle as a programmer to update a
3182 pair programmed device. Due to limited memory resources in the
3183 cc1111, we don't support programming directly over USB for these
3188 <title>Updating TeleMetrum v1.x Firmware</title>
3189 <orderedlist inheritnum='inherit' numeration='arabic'>
3192 Find the 'programming cable' that you got as part of the starter
3193 kit, that has a red 8-pin MicroMaTch connector on one end and a
3194 red 4-pin MicroMaTch connector on the other end.
3199 Take the 2 screws out of the TeleDongle case to get access
3200 to the circuit board.
3205 Plug the 8-pin end of the programming cable to the
3206 matching connector on the TeleDongle, and the 4-pin end to the
3207 matching connector on the TeleMetrum.
3208 Note that each MicroMaTch connector has an alignment pin that
3209 goes through a hole in the PC board when you have the cable
3215 Attach a battery to the TeleMetrum board.
3220 Plug the TeleDongle into your computer's USB port, and power
3226 Run AltosUI, and select 'Flash Image' from the File menu.
3231 Pick the TeleDongle device from the list, identifying it as the
3237 Select the image you want put on the TeleMetrum, which should have a
3238 name in the form telemetrum-v1.2-1.0.0.ihx. It should be visible
3239 in the default directory, if not you may have to poke around
3240 your system to find it.
3245 Make sure the configuration parameters are reasonable
3246 looking. If the serial number and/or RF configuration
3247 values aren't right, you'll need to change them.
3252 Hit the 'OK' button and the software should proceed to flash
3253 the TeleMetrum with new firmware, showing a progress bar.
3258 Confirm that the TeleMetrum board seems to have updated OK, which you
3259 can do by plugging in to it over USB and using a terminal program
3260 to connect to the board and issue the 'v' command to check
3266 If something goes wrong, give it another try.
3272 <title>Updating TeleMini Firmware</title>
3273 <orderedlist inheritnum='inherit' numeration='arabic'>
3276 You'll need a special 'programming cable' to reprogram the
3277 TeleMini. You can make your own using an 8-pin MicroMaTch
3278 connector on one end and a set of four pins on the other.
3283 Take the 2 screws out of the TeleDongle case to get access
3284 to the circuit board.
3289 Plug the 8-pin end of the programming cable to the matching
3290 connector on the TeleDongle, and the 4-pins into the holes
3291 in the TeleMini circuit board. Note that the MicroMaTch
3292 connector has an alignment pin that goes through a hole in
3293 the PC board when you have the cable oriented correctly, and
3294 that pin 1 on the TeleMini board is marked with a square pad
3295 while the other pins have round pads.
3300 Attach a battery to the TeleMini board.
3305 Plug the TeleDongle into your computer's USB port, and power
3311 Run AltosUI, and select 'Flash Image' from the File menu.
3316 Pick the TeleDongle device from the list, identifying it as the
3322 Select the image you want put on the TeleMini, which should have a
3323 name in the form telemini-v1.0-1.0.0.ihx. It should be visible
3324 in the default directory, if not you may have to poke around
3325 your system to find it.
3330 Make sure the configuration parameters are reasonable
3331 looking. If the serial number and/or RF configuration
3332 values aren't right, you'll need to change them.
3337 Hit the 'OK' button and the software should proceed to flash
3338 the TeleMini with new firmware, showing a progress bar.
3343 Confirm that the TeleMini board seems to have updated OK, which you
3344 can do by configuring it over the radio link through the TeleDongle, or
3345 letting it come up in “flight” mode and listening for telemetry.
3350 If something goes wrong, give it another try.
3356 <title>Updating TeleDongle Firmware</title>
3358 Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
3359 firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
3361 <orderedlist inheritnum='inherit' numeration='arabic'>
3364 Find the 'programming cable' that you got as part of the starter
3365 kit, that has a red 8-pin MicroMaTch connector on one end and a
3366 red 4-pin MicroMaTch connector on the other end.
3371 Find the USB cable that you got as part of the starter kit, and
3372 plug the “mini” end in to the mating connector on TeleMetrum or TeleDongle.
3377 Take the 2 screws out of the TeleDongle case to get access
3378 to the circuit board.
3383 Plug the 8-pin end of the programming cable to the
3384 matching connector on the programmer, and the 4-pin end to the
3385 matching connector on the TeleDongle.
3386 Note that each MicroMaTch connector has an alignment pin that
3387 goes through a hole in the PC board when you have the cable
3393 Attach a battery to the TeleMetrum board if you're using one.
3398 Plug both the programmer and the TeleDongle into your computer's USB
3399 ports, and power up the programmer.
3404 Run AltosUI, and select 'Flash Image' from the File menu.
3409 Pick the programmer device from the list, identifying it as the
3415 Select the image you want put on the TeleDongle, which should have a
3416 name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
3417 in the default directory, if not you may have to poke around
3418 your system to find it.
3423 Make sure the configuration parameters are reasonable
3424 looking. If the serial number and/or RF configuration
3425 values aren't right, you'll need to change them. The TeleDongle
3426 serial number is on the “bottom” of the circuit board, and can
3427 usually be read through the translucent blue plastic case without
3428 needing to remove the board from the case.
3433 Hit the 'OK' button and the software should proceed to flash
3434 the TeleDongle with new firmware, showing a progress bar.
3439 Confirm that the TeleDongle board seems to have updated OK, which you
3440 can do by plugging in to it over USB and using a terminal program
3441 to connect to the board and issue the 'v' command to check
3442 the version, etc. Once you're happy, remove the programming cable
3443 and put the cover back on the TeleDongle.
3448 If something goes wrong, give it another try.
3453 Be careful removing the programming cable from the locking 8-pin
3454 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
3455 screwdriver or knife blade to gently pry the locking ears out
3456 slightly to extract the connector. We used a locking connector on
3457 TeleMetrum to help ensure that the cabling to companion boards
3458 used in a rocket don't ever come loose accidentally in flight.
3463 <title>Hardware Specifications</title>
3466 TeleMega Specifications
3471 Recording altimeter for model rocketry.
3476 Supports dual deployment and four auxiliary pyro channels
3477 (a total of 6 events).
3482 70cm 40mW ham-band transceiver for telemetry down-link.
3487 Barometric pressure sensor good to 100k feet MSL.
3492 1-axis high-g accelerometer for motor characterization, capable of
3498 9-axis IMU including integrated 3-axis accelerometer,
3499 3-axis gyroscope and 3-axis magnetometer.
3504 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
3509 On-board 8 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 Can use either main system Li-Po or optional separate pyro battery
3530 3.25 x 1.25 inch board designed to fit inside 38mm air-frame coupler tube.
3537 TeleMetrum v2 Specifications
3542 Recording altimeter for model rocketry.
3547 Supports dual deployment (can fire 2 ejection charges).
3552 70cm, 40mW ham-band transceiver for telemetry down-link.
3557 Barometric pressure sensor good to 100k feet MSL.
3562 1-axis high-g accelerometer for motor characterization, capable of
3568 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
3573 On-board 8 Megabyte non-volatile memory for flight data storage.
3578 USB interface for battery charging, configuration, and data recovery.
3583 Fully integrated support for Li-Po rechargeable batteries.
3588 Uses Li-Po to fire e-matches, can be modified to support
3589 optional separate pyro battery if needed.
3594 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
3600 <title>TeleMetrum v1 Specifications</title>
3604 Recording altimeter for model rocketry.
3609 Supports dual deployment (can fire 2 ejection charges).
3614 70cm, 10mW ham-band transceiver for telemetry down-link.
3619 Barometric pressure sensor good to 45k feet MSL.
3624 1-axis high-g accelerometer for motor characterization, capable of
3625 +/- 50g using default part.
3630 On-board, integrated GPS receiver with 5Hz update rate capability.
3635 On-board 1 megabyte non-volatile memory for flight data storage.
3640 USB interface for battery charging, configuration, and data recovery.
3645 Fully integrated support for Li-Po rechargeable batteries.
3650 Uses Li-Po to fire e-matches, can be modified to support
3651 optional separate pyro battery if needed.
3656 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
3663 TeleMini v2.0 Specifications
3668 Recording altimeter for model rocketry.
3673 Supports dual deployment (can fire 2 ejection charges).
3678 70cm, 10mW ham-band transceiver for telemetry down-link.
3683 Barometric pressure sensor good to 100k feet MSL.
3688 On-board 1 megabyte non-volatile memory for flight data storage.
3693 USB interface for configuration, and data recovery.
3698 Support for Li-Po rechargeable batteries (using an
3699 external charger), or any 3.7-15V external battery.
3704 Uses Li-Po to fire e-matches, can be modified to support
3705 optional separate pyro battery if needed.
3710 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
3717 TeleMini v1.0 Specifications
3722 Recording altimeter for model rocketry.
3727 Supports dual deployment (can fire 2 ejection charges).
3732 70cm, 10mW ham-band transceiver for telemetry down-link.
3737 Barometric pressure sensor good to 45k feet MSL.
3742 On-board 5 kilobyte non-volatile memory for flight data storage.
3747 RF interface for configuration, and data recovery.
3752 Support for Li-Po rechargeable batteries, using an external charger.
3757 Uses Li-Po to fire e-matches, can be modified to support
3758 optional separate pyro battery if needed.
3763 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube.
3770 EasyMini Specifications
3775 Recording altimeter for model rocketry.
3780 Supports dual deployment (can fire 2 ejection charges).
3785 Barometric pressure sensor good to 100k feet MSL.
3790 On-board 1 megabyte non-volatile memory for flight data storage.
3795 USB interface for configuration, and data recovery.
3800 Support for Li-Po rechargeable batteries (using an
3801 external charger), or any 3.7-15V external battery.
3806 Uses Li-Po to fire e-matches, can be modified to support
3807 optional separate pyro battery if needed.
3812 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
3821 <emphasis>TeleMetrum seems to shut off when disconnected from the
3822 computer.</emphasis> <?linebreak?>
3823 Make sure the battery is adequately charged. Remember the
3824 unit will pull more power than the USB port can deliver before the
3825 GPS enters “locked” mode. The battery charges best when TeleMetrum
3829 <emphasis>It's impossible to stop the TeleDongle when it's in “p” mode, I have
3830 to unplug the USB cable? </emphasis><?linebreak?>
3831 Make sure you have tried to “escape out” of
3832 this mode. If this doesn't work the reboot procedure for the
3833 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
3834 outgoing buffer IF your “escape out” ('~~') does not work.
3835 At this point using either 'ao-view' (or possibly
3836 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
3840 <emphasis>The amber LED (on the TeleMetrum) lights up when both
3841 battery and USB are connected. Does this mean it's charging?
3842 </emphasis><?linebreak?>
3843 Yes, the yellow LED indicates the charging at the 'regular' rate.
3844 If the led is out but the unit is still plugged into a USB port,
3845 then the battery is being charged at a 'trickle' rate.
3848 <emphasis>There are no “dit-dah-dah-dit” sound or lights like the manual
3849 mentions?</emphasis><?linebreak?>
3850 That's the “pad” mode. Weak batteries might be the problem.
3851 It is also possible that the flight computer is horizontal and the
3853 is instead a “dit-dit” meaning 'idle'. For TeleMini, it's possible that
3854 it received a command packet which would have left it in “pad” mode.
3857 <emphasis>How do I save flight data?</emphasis><?linebreak?>
3858 Live telemetry is written to file(s) whenever AltosUI is connected
3859 to the TeleDongle. The file area defaults to ~/TeleMetrum
3860 but is easily changed using the menus in AltosUI. The files that
3861 are written end in '.telem'. The after-flight
3862 data-dumped files will end in .eeprom and represent continuous data
3863 unlike the .telem files that are subject to losses
3864 along the RF data path.
3865 See the above instructions on what and how to save the eeprom stored
3866 data after physically retrieving your altimeter. Make sure to save
3867 the on-board data after each flight; while the TeleMetrum can store
3868 multiple flights, you never know when you'll lose the altimeter...
3872 <title>Notes for Older Software</title>
3875 Before AltosUI was written, using Altus Metrum devices required
3876 some finesse with the Linux command line. There was a limited
3877 GUI tool, ao-view, which provided functionality similar to the
3878 Monitor Flight window in AltosUI, but everything else was a
3879 fairly 80's experience. This appendix includes documentation for
3880 using that software.
3884 Both TeleMetrum and TeleDongle can be directly communicated
3885 with using USB ports. The first thing you should try after getting
3886 both units plugged into to your computer's USB port(s) is to run
3887 'ao-list' from a terminal-window to see what port-device-name each
3888 device has been assigned by the operating system.
3889 You will need this information to access the devices via their
3890 respective on-board firmware and data using other command line
3891 programs in the AltOS software suite.
3894 TeleMini can be communicated with through a TeleDongle device
3895 over the radio link. When first booted, TeleMini listens for a
3896 TeleDongle device and if it receives a packet, it goes into
3897 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be
3898 launched. The easiest way to get it talking is to start the
3899 communication link on the TeleDongle and the power up the
3903 To access the device's firmware for configuration you need a terminal
3904 program such as you would use to talk to a modem. The software
3905 authors prefer using the program 'cu' which comes from the UUCP package
3906 on most Unix-like systems such as Linux. An example command line for
3907 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
3908 indicated from running the
3909 ao-list program. Another reasonable terminal program for Linux is
3910 'cutecom'. The default 'escape'
3911 character used by CU (i.e. the character you use to
3912 issue commands to cu itself instead of sending the command as input
3913 to the connected device) is a '~'. You will need this for use in
3914 only two different ways during normal operations. First is to exit
3915 the program by sending a '~.' which is called a 'escape-disconnect'
3916 and allows you to close-out from 'cu'. The
3917 second use will be outlined later.
3920 All of the Altus Metrum devices share the concept of a two level
3921 command set in their firmware.
3922 The first layer has several single letter commands. Once
3923 you are using 'cu' (or 'cutecom') sending (typing) a '?'
3924 returns a full list of these
3925 commands. The second level are configuration sub-commands accessed
3926 using the 'c' command, for
3927 instance typing 'c?' will give you this second level of commands
3928 (all of which require the
3929 letter 'c' to access). Please note that most configuration options
3930 are stored only in Flash memory; TeleDongle doesn't provide any storage
3931 for these options and so they'll all be lost when you unplug it.
3934 Try setting these configuration ('c' or second level menu) values. A good
3935 place to start is by setting your call sign. By default, the boards
3936 use 'N0CALL' which is cute, but not exactly legal!
3937 Spend a few minutes getting comfortable with the units, their
3938 firmware, and 'cu' (or possibly 'cutecom').
3939 For instance, try to send
3940 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
3941 Verify you can connect and disconnect from the units while in your
3942 terminal program by sending the escape-disconnect mentioned above.
3945 To set the radio frequency, use the 'c R' command to specify the
3946 radio transceiver configuration parameter. This parameter is computed
3947 using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
3948 the standard calibration reference frequency, 'S', (normally 434.550MHz):
3952 Round the result to the nearest integer value.
3953 As with all 'c' sub-commands, follow this with a 'c w' to write the
3954 change to the parameter block in the on-board flash on
3955 your altimeter board if you want the change to stay in place across reboots.
3958 To set the apogee delay, use the 'c d' command.
3959 As with all 'c' sub-commands, follow this with a 'c w' to write the
3960 change to the parameter block in the on-board DataFlash chip.
3963 To set the main deployment altitude, use the 'c m' command.
3964 As with all 'c' sub-commands, follow this with a 'c w' to write the
3965 change to the parameter block in the on-board DataFlash chip.
3968 To calibrate the radio frequency, connect the UHF antenna port to a
3969 frequency counter, set the board to 434.550MHz, and use the 'C'
3970 command to generate a CW carrier. Wait for the transmitter temperature
3971 to stabilize and the frequency to settle down.
3972 Then, divide 434.550 MHz by the
3973 measured frequency and multiply by the current radio cal value show
3974 in the 'c s' command. For an unprogrammed board, the default value
3975 is 1186611. Take the resulting integer and program it using the 'c f'
3976 command. Testing with the 'C' command again should show a carrier
3977 within a few tens of Hertz of the intended frequency.
3978 As with all 'c' sub-commands, follow this with a 'c w' to write the
3979 change to the parameter block in the on-board DataFlash chip.
3982 Note that the 'reboot' command, which is very useful on the altimeters,
3983 will likely just cause problems with the dongle. The *correct* way
3984 to reset the dongle is just to unplug and re-plug it.
3987 A fun thing to do at the launch site and something you can do while
3988 learning how to use these units is to play with the radio link access
3989 between an altimeter and the TeleDongle. Be aware that you *must* create
3990 some physical separation between the devices, otherwise the link will
3991 not function due to signal overload in the receivers in each device.
3994 Now might be a good time to take a break and read the rest of this
3995 manual, particularly about the two “modes” that the altimeters
3996 can be placed in. TeleMetrum uses the position of the device when booting
3997 up will determine whether the unit is in “pad” or “idle” mode. TeleMini
3998 enters “idle” mode when it receives a command packet within the first 5 seconds
3999 of being powered up, otherwise it enters “pad” mode.
4002 You can access an altimeter in idle mode from the TeleDongle's USB
4003 connection using the radio link
4004 by issuing a 'p' command to the TeleDongle. Practice connecting and
4005 disconnecting ('~~' while using 'cu') from the altimeter. If
4006 you cannot escape out of the “p” command, (by using a '~~' when in
4007 CU) then it is likely that your kernel has issues. Try a newer version.
4010 Using this radio link allows you to configure the altimeter, test
4011 fire e-matches and igniters from the flight line, check pyro-match
4012 continuity and so forth. You can leave the unit turned on while it
4013 is in 'idle mode' and then place the
4014 rocket vertically on the launch pad, walk away and then issue a
4015 reboot command. The altimeter will reboot and start sending data
4016 having changed to the “pad” mode. If the TeleDongle is not receiving
4017 this data, you can disconnect 'cu' from the TeleDongle using the
4018 procedures mentioned above and THEN connect to the TeleDongle from
4019 inside 'ao-view'. If this doesn't work, disconnect from the
4020 TeleDongle, unplug it, and try again after plugging it back in.
4023 In order to reduce the chance of accidental firing of pyrotechnic
4024 charges, the command to fire a charge is intentionally somewhat
4025 difficult to type, and the built-in help is slightly cryptic to
4026 prevent accidental echoing of characters from the help text back at
4027 the board from firing a charge. The command to fire the apogee
4028 drogue charge is 'i DoIt drogue' and the command to fire the main
4029 charge is 'i DoIt main'.
4032 On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
4033 and 'ao-view' will both auditorily announce and visually indicate
4035 Now you can launch knowing that you have a good data path and
4036 good satellite lock for flight data and recovery. Remember
4037 you MUST tell ao-view to connect to the TeleDongle explicitly in
4038 order for ao-view to be able to receive data.
4041 The altimeters provide RDF (radio direction finding) tones on
4042 the pad, during descent and after landing. These can be used to
4043 locate the rocket using a directional antenna; the signal
4044 strength providing an indication of the direction from receiver to rocket.
4047 TeleMetrum also provides GPS tracking data, which can further simplify
4048 locating the rocket once it has landed. (The last good GPS data
4049 received before touch-down will be on the data screen of 'ao-view'.)
4052 Once you have recovered the rocket you can download the eeprom
4053 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
4054 either a USB cable or over the radio link using TeleDongle.
4055 And by following the man page for 'ao-postflight' you can create
4056 various data output reports, graphs, and even KML data to see the
4057 flight trajectory in Google-earth. (Moving the viewing angle making
4058 sure to connect the yellow lines while in Google-earth is the proper
4062 As for ao-view.... some things are in the menu but don't do anything
4063 very useful. The developers have stopped working on ao-view to focus
4064 on a new, cross-platform ground station program. So ao-view may or
4065 may not be updated in the future. Mostly you just use
4066 the Log and Device menus. It has a wonderful display of the incoming
4067 flight data and I am sure you will enjoy what it has to say to you
4068 once you enable the voice output!
4072 <title>Drill Templates</title>
4074 These images, when printed, provide precise templates for the
4075 mounting holes in Altus Metrum flight computers
4078 <title>TeleMega template</title>
4080 TeleMega has overall dimensions of 1.250 x 3.250 inches, and
4081 the mounting holes are sized for use with 4-40 or M3 screws.
4084 <mediaobject id="TeleMegaTemplate">
4086 <imagedata format="SVG" fileref="telemega-outline.svg"/>
4092 <title>TeleMetrum template</title>
4094 TeleMetrum has overall dimensions of 1.000 x 2.750 inches, and the
4095 mounting holes are sized for use with 4-40 or M3 screws.
4098 <mediaobject id="TeleMetrumTemplate">
4100 <imagedata format="SVG" fileref="telemetrum.svg"/>
4106 <title>TeleMini v2/EasyMini template</title>
4108 TeleMini v2 and EasyMini have overall dimensions of 0.800 x 1.500 inches, and the
4109 mounting holes are sized for use with 4-40 or M3 screws.
4112 <mediaobject id="MiniTemplate">
4114 <imagedata format="SVG" fileref="easymini-outline.svg"/>
4120 <title>TeleMini v1 template</title>
4122 TeleMini has overall dimensions of 0.500 x 1.500 inches, and the
4123 mounting holes are sized for use with 2-56 or M2 screws.
4126 <mediaobject id="TeleMiniTemplate">
4128 <imagedata format="SVG" fileref="telemini.svg"/>
4135 <title>Calibration</title>
4137 There are only two calibrations required for TeleMetrum and
4138 TeleMega, and only one for TeleDongle, TeleMini and EasyMini.
4139 All boards are shipped from the factory pre-calibrated, but
4140 the procedures are documented here in case they are ever
4141 needed. Re-calibration is not supported by AltosUI, you must
4142 connect to the board with a serial terminal program and
4143 interact directly with the on-board command interpreter to
4147 <title>Radio Frequency</title>
4149 The radio frequency is synthesized from a clock based on the
4150 crystal on the board. The actual frequency of this oscillator
4151 must be measured to generate a calibration constant. While our
4153 bandwidth is wide enough to allow boards to communicate even when
4154 their oscillators are not on exactly the same frequency, performance
4155 is best when they are closely matched.
4156 Radio frequency calibration requires a calibrated frequency counter.
4157 Fortunately, once set, the variation in frequency due to aging and
4158 temperature changes is small enough that re-calibration by customers
4159 should generally not be required.
4162 To calibrate the radio frequency, connect the UHF antenna
4163 port to a frequency counter, set the board to 434.550MHz,
4164 and use the 'C' command in the on-board command interpreter
4165 to generate a CW carrier. For USB-enabled boards, this is
4166 best done over USB. For TeleMini v1, note that the only way
4167 to escape the 'C' command is via power cycle since the board
4168 will no longer be listening for commands once it starts
4169 generating a CW carrier.
4172 Wait for the transmitter temperature to stabilize and the frequency
4173 to settle down. Then, divide 434.550 MHz by the
4174 measured frequency and multiply by the current radio cal value show
4175 in the 'c s' command. For an unprogrammed board, the default value
4176 is 1186611. Take the resulting integer and program it using the 'c f'
4177 command. Testing with the 'C' command again should show a carrier
4178 within a few tens of Hertz of the intended frequency.
4179 As with all 'c' sub-commands, follow this with a 'c w' to write the
4180 change to the parameter block in the on-board storage chip.
4183 Note that any time you re-do the radio frequency calibration, the
4184 radio frequency is reset to the default 434.550 Mhz. If you want
4185 to use another frequency, you will have to set that again after
4186 calibration is completed.
4190 <title>TeleMetrum and TeleMega Accelerometers</title>
4192 While barometric sensors are factory-calibrated,
4193 accelerometers are not, and so each must be calibrated once
4194 installed in a flight computer. Explicitly calibrating the
4195 accelerometers also allows us to load any compatible device.
4196 We perform a two-point calibration using gravity.
4199 To calibrate the acceleration sensor, use the 'c a 0' command. You
4200 will be prompted to orient the board vertically with the UHF antenna
4201 up and press a key, then to orient the board vertically with the
4202 UHF antenna down and press a key. Note that the accuracy of this
4203 calibration depends primarily on how perfectly vertical and still
4204 the board is held during the cal process. As with all 'c'
4205 sub-commands, follow this with a 'c w' to write the
4206 change to the parameter block in the on-board DataFlash chip.
4209 The +1g and -1g calibration points are included in each telemetry
4210 frame and are part of the header stored in onboard flash to be
4211 downloaded after flight. We always store and return raw ADC
4212 samples for each sensor... so nothing is permanently “lost” or
4213 “damaged” if the calibration is poor.
4216 In the unlikely event an accel cal goes badly, it is possible
4217 that TeleMetrum or TeleMega may always come up in 'pad mode'
4218 and as such not be listening to either the USB or radio link.
4219 If that happens, there is a special hook in the firmware to
4220 force the board back in to 'idle mode' so you can re-do the
4221 cal. To use this hook, you just need to ground the SPI clock
4222 pin at power-on. This pin is available as pin 2 on the 8-pin
4223 companion connector, and pin 1 is ground. So either
4224 carefully install a fine-gauge wire jumper between the two
4225 pins closest to the index hole end of the 8-pin connector, or
4226 plug in the programming cable to the 8-pin connector and use
4227 a small screwdriver or similar to short the two pins closest
4228 to the index post on the 4-pin end of the programming cable,
4229 and power up the board. It should come up in 'idle mode'
4230 (two beeps), allowing a re-cal.
4235 <title>Release Notes</title>
4237 <title>Version 1.3</title>
4239 xmlns:xi="http://www.w3.org/2001/XInclude"
4240 href="release-notes-1.3.xsl"
4241 xpointer="xpointer(/article/*)"/>
4244 <title>Version 1.2.1</title>
4246 xmlns:xi="http://www.w3.org/2001/XInclude"
4247 href="release-notes-1.2.1.xsl"
4248 xpointer="xpointer(/article/*)"/>
4251 <title>Version 1.2</title>
4253 xmlns:xi="http://www.w3.org/2001/XInclude"
4254 href="release-notes-1.2.xsl"
4255 xpointer="xpointer(/article/*)"/>
4258 <title>Version 1.1.1</title>
4260 xmlns:xi="http://www.w3.org/2001/XInclude"
4261 href="release-notes-1.1.1.xsl"
4262 xpointer="xpointer(/article/*)"/>
4265 <title>Version 1.1</title>
4267 xmlns:xi="http://www.w3.org/2001/XInclude"
4268 href="release-notes-1.1.xsl"
4269 xpointer="xpointer(/article/*)"/>
4272 <title>Version 1.0.1</title>
4274 xmlns:xi="http://www.w3.org/2001/XInclude"
4275 href="release-notes-1.0.1.xsl"
4276 xpointer="xpointer(/article/*)"/>
4279 <title>Version 0.9.2</title>
4281 xmlns:xi="http://www.w3.org/2001/XInclude"
4282 href="release-notes-0.9.2.xsl"
4283 xpointer="xpointer(/article/*)"/>
4286 <title>Version 0.9</title>
4288 xmlns:xi="http://www.w3.org/2001/XInclude"
4289 href="release-notes-0.9.xsl"
4290 xpointer="xpointer(/article/*)"/>
4293 <title>Version 0.8</title>
4295 xmlns:xi="http://www.w3.org/2001/XInclude"
4296 href="release-notes-0.8.xsl"
4297 xpointer="xpointer(/article/*)"/>
4300 <title>Version 0.7.1</title>
4302 xmlns:xi="http://www.w3.org/2001/XInclude"
4303 href="release-notes-0.7.1.xsl"
4304 xpointer="xpointer(/article/*)"/>
4309 <!-- LocalWords: Altusmetrum
projects / fw / altos / blob