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2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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5 <title>The Altus Metrum System</title>
6 <subtitle>An Owner's Manual for Altus Metrum Rocketry Electronics</subtitle>
9 <firstname>Bdale</firstname>
10 <surname>Garbee</surname>
13 <firstname>Keith</firstname>
14 <surname>Packard</surname>
17 <firstname>Bob</firstname>
18 <surname>Finch</surname>
21 <firstname>Anthony</firstname>
22 <surname>Towns</surname>
26 <holder>Bdale Garbee and Keith Packard</holder>
30 This document is released under the terms of the
31 <ulink url="http://creativecommons.org/licenses/by-sa/3.0/">
32 Creative Commons ShareAlike 3.0
39 <revnumber>1.3</revnumber>
40 <date>12 November 2013</date>
42 Updated for software version 1.3. Version 1.3 adds support
43 for TeleMega, TeleMetrum v2.0, TeleMini v2.0 and EasyMini
44 and fixes bugs in AltosUI and the AltOS firmware.
48 <revnumber>1.2.1</revnumber>
49 <date>21 May 2013</date>
51 Updated for software version 1.2. Version 1.2 adds support
52 for TeleBT and AltosDroid. It also adds a few minor features
53 and fixes bugs in AltosUI and the AltOS firmware.
57 <revnumber>1.2</revnumber>
58 <date>18 April 2013</date>
60 Updated for software version 1.2. Version 1.2 adds support
61 for MicroPeak and the MicroPeak USB interface.
65 <revnumber>1.1.1</revnumber>
66 <date>16 September 2012</date>
68 Updated for software version 1.1.1 Version 1.1.1 fixes a few
69 bugs found in version 1.1.
73 <revnumber>1.1</revnumber>
74 <date>13 September 2012</date>
76 Updated for software version 1.1. Version 1.1 has new
77 features but is otherwise compatible with version 1.0.
81 <revnumber>1.0</revnumber>
82 <date>24 August 2011</date>
84 Updated for software version 1.0. Note that 1.0 represents a
85 telemetry format change, meaning both ends of a link
86 (TeleMetrum/TeleMini and TeleDongle) must be updated or
87 communications will fail.
91 <revnumber>0.9</revnumber>
92 <date>18 January 2011</date>
94 Updated for software version 0.9. Note that 0.9 represents a
95 telemetry format change, meaning both ends of a link (TeleMetrum and
96 TeleDongle) must be updated or communications will fail.
100 <revnumber>0.8</revnumber>
101 <date>24 November 2010</date>
102 <revremark>Updated for software version 0.8 </revremark>
107 <title>Acknowledgments</title>
109 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing “The
110 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
111 Kit” which formed the basis of the original Getting Started chapter
112 in this manual. Bob was one of our first customers for a production
113 TeleMetrum, and his continued enthusiasm and contributions
114 are immensely gratifying and highly appreciated!
117 And thanks to Anthony (AJ) Towns for major contributions including
118 the AltosUI graphing and site map code and associated documentation.
119 Free software means that our customers and friends can become our
120 collaborators, and we certainly appreciate this level of
124 Have fun using these products, and we hope to meet all of you
125 out on the rocket flight line somewhere.
128 NAR #87103, TRA #12201
130 Keith Packard, KD7SQG
131 NAR #88757, TRA #12200
136 <title>Introduction and Overview</title>
138 Welcome to the Altus Metrum community! Our circuits and software reflect
139 our passion for both hobby rocketry and Free Software. We hope their
140 capabilities and performance will delight you in every way, but by
141 releasing all of our hardware and software designs under open licenses,
142 we also hope to empower you to take as active a role in our collective
146 The first device created for our community was TeleMetrum, a dual
147 deploy altimeter with fully integrated GPS and radio telemetry
148 as standard features, and a “companion interface” that will
149 support optional capabilities in the future. The latest version
150 of TeleMetrum, v2.0, has all of the same features but with
151 improved sensors and radio to offer increased performance.
154 Our second device was TeleMini, a dual deploy altimeter with
155 radio telemetry and radio direction finding. The first version
156 of this device was only 13mm by 38mm (½ inch by 1½ inches) and
157 could fit easily in an 18mm air-frame. The latest version, v2.0,
158 includes a beeper, USB data download and extended on-board
159 flight logging, along with an improved barometric sensor.
162 TeleMega is our most sophisticated device, including six pyro
163 channels (four of which are fully programmable), integrated GPS,
164 integrated gyroscopes for staging/air-start inhibit and high
165 performance telemetry.
168 EasyMini is a dual-deploy altimeter with logging and built-in
172 TeleDongle was our first ground station, providing a USB to RF
173 interfaces for communicating with the altimeters. Combined with
174 your choice of antenna and notebook computer, TeleDongle and our
175 associated user interface software form a complete ground
176 station capable of logging and displaying in-flight telemetry,
177 aiding rocket recovery, then processing and archiving flight
178 data for analysis and review.
181 For a slightly more portable ground station experience that also
182 provides direct rocket recovery support, TeleBT offers flight
183 monitoring and data logging using a Bluetooth connection between
184 the receiver and an Android device that has the Altos Droid
185 application installed from the Google Play store.
188 More products will be added to the Altus Metrum family over time, and
189 we currently envision that this will be a single, comprehensive manual
190 for the entire product family.
194 <title>Getting Started</title>
196 The first thing to do after you check the inventory of parts in your
197 “starter kit” is to charge the battery.
200 For TeleMetrum and TeleMega, the battery can be charged by plugging it into the
201 corresponding socket of the device and then using the USB
202 cable to plug the flight computer into your computer's USB socket. The
203 on-board circuitry will charge the battery whenever it is plugged
204 in, because the on-off switch does NOT control the
208 On TeleMetrum v1 boards, when the GPS chip is initially
209 searching for satellites, TeleMetrum will consume more current
210 than it can pull from the USB port, so the battery must be
211 attached in order to get satellite lock. Once GPS is locked,
212 the current consumption goes back down enough to enable charging
213 while running. So it's a good idea to fully charge the battery
214 as your first item of business so there is no issue getting and
215 maintaining satellite lock. The yellow charge indicator led
216 will go out when the battery is nearly full and the charger goes
217 to trickle charge. It can take several hours to fully recharge a
218 deeply discharged battery.
221 TeleMetrum v2.0 and TeleMega use a higher power battery charger,
222 allowing them to charge the battery while running the board at
223 maximum power. When the battery is charging, or when the board
224 is consuming a lot of power, the red LED will be lit. When the
225 battery is fully charged, the green LED will be lit. When the
226 battery is damaged or missing, both LEDs will be lit, which
230 The Lithium Polymer TeleMini and EasyMini battery can be charged by
231 disconnecting it from the board and plugging it into a
232 standalone battery charger such as the LipoCharger product
233 included in TeleMini Starter Kits, and connecting that via a USB
234 cable to a laptop or other USB power source.
237 You can also choose to use another battery with TeleMini v2.0
238 and EasyMini, anything supplying between 4 and 12 volts should
239 work fine (like a standard 9V battery), but if you are planning
240 to fire pyro charges, ground testing is required to verify that
241 the battery supplies enough current.
244 The other active device in the starter kit is the TeleDongle USB to
245 RF interface. If you plug it in to your Mac or Linux computer it should
246 “just work”, showing up as a serial port device. Windows systems need
247 driver information that is part of the AltOS download to know that the
248 existing USB modem driver will work. We therefore recommend installing
249 our software before plugging in TeleDongle if you are using a Windows
250 computer. If you are using Linux and are having problems, try moving
251 to a fresher kernel (2.6.33 or newer), as the USB serial driver had
252 ugly bugs in some earlier versions.
255 Next you should obtain and install the AltOS software. These
256 include the AltosUI ground station program, current firmware
257 images for all of the hardware, and a number of standalone
258 utilities that are rarely needed. Pre-built binary packages are
259 available for Linux, Microsoft Windows, and recent MacOSX
260 versions. Full source code and build instructions are also
261 available. The latest version may always be downloaded from
262 <ulink url="http://altusmetrum.org/AltOS"/>.
265 If you're using a TeleBT instead of the TeleDongle, you'll want
266 to go install the Altos Droid application from the Google Play
267 store. You don't need a data plan to use Altos Droid, but
268 without network access, the Map view will be less useful as it
269 won't contain any map data. You can also use TeleBT connected
270 over USB with your laptop computer; it acts exactly like a
271 TeleDongle. Anywhere this manual talks about TeleDongle, you can
272 also read that as 'and TeleBT when connected via USB'.
276 <title>Handling Precautions</title>
278 All Altus Metrum products are sophisticated electronic devices.
279 When handled gently and properly installed in an air-frame, they
280 will deliver impressive results. However, as with all electronic
281 devices, there are some precautions you must take.
284 The Lithium Polymer rechargeable batteries have an
285 extraordinary power density. This is great because we can fly with
286 much less battery mass than if we used alkaline batteries or previous
287 generation rechargeable batteries... but if they are punctured
288 or their leads are allowed to short, they can and will release their
290 Thus we recommend that you take some care when handling our batteries
291 and consider giving them some extra protection in your air-frame. We
292 often wrap them in suitable scraps of closed-cell packing foam before
293 strapping them down, for example.
296 The barometric sensors used on all of our flight computers are
297 sensitive to sunlight. In normal mounting situations, the baro sensor
298 and all of the other surface mount components
299 are “down” towards whatever the underlying mounting surface is, so
300 this is not normally a problem. Please consider this, though, when
301 designing an installation, for example, in an air-frame with a
302 see-through plastic payload bay. It is particularly important to
303 consider this with TeleMini v1.0, both because the baro sensor is on the
304 “top” of the board, and because many model rockets with payload bays
305 use clear plastic for the payload bay! Replacing these with an opaque
306 cardboard tube, painting them, or wrapping them with a layer of masking
307 tape are all reasonable approaches to keep the sensor out of direct
311 The barometric sensor sampling port must be able to “breathe”,
312 both by not being covered by foam or tape or other materials that might
313 directly block the hole on the top of the sensor, and also by having a
314 suitable static vent to outside air.
317 As with all other rocketry electronics, Altus Metrum altimeters must
318 be protected from exposure to corrosive motor exhaust and ejection
323 <title>Altus Metrum Hardware</title>
325 <title>Overview</title>
327 Here's the full set of Altus Metrum products, both in
328 production and retired.
331 <title>Altus Metrum Electronics</title>
332 <?dbfo keep-together="always"?>
333 <tgroup cols='8' align='center' colsep='1' rowsep='1'>
334 <colspec align='center' colwidth='*' colname='Device'/>
335 <colspec align='center' colwidth='*' colname='Barometer'/>
336 <colspec align='center' colwidth='*' colname='Z-axis accelerometer'/>
337 <colspec align='center' colwidth='*' colname='GPS'/>
338 <colspec align='center' colwidth='*' colname='3D sensors'/>
339 <colspec align='center' colwidth='*' colname='Storage'/>
340 <colspec align='center' colwidth='*' colname='RF'/>
341 <colspec align='center' colwidth='*' colname='Battery'/>
344 <entry align='center'>Device</entry>
345 <entry align='center'>Barometer</entry>
346 <entry align='center'>Z-axis accelerometer</entry>
347 <entry align='center'>GPS</entry>
348 <entry align='center'>3D sensors</entry>
349 <entry align='center'>Storage</entry>
350 <entry align='center'>RF Output</entry>
351 <entry align='center'>Battery</entry>
356 <entry>TeleMetrum v1.0</entry>
357 <entry><para>MP3H6115 10km (33k')</para></entry>
358 <entry><para>MMA2202 50g</para></entry>
359 <entry>SkyTraq</entry>
366 <entry>TeleMetrum v1.1</entry>
367 <entry><para>MP3H6115 10km (33k')</para></entry>
368 <entry><para>MMA2202 50g</para></entry>
369 <entry>SkyTraq</entry>
376 <entry>TeleMetrum v1.2</entry>
377 <entry><para>MP3H6115 10km (33k')</para></entry>
378 <entry><para>ADXL78 70g</para></entry>
379 <entry>SkyTraq</entry>
386 <entry>TeleMetrum v2.0</entry>
387 <entry><para>MS5607 30km (100k')</para></entry>
388 <entry><para>MMA6555 102g</para></entry>
389 <entry>uBlox Max-7Q</entry>
396 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
397 <entry><para>MP3H6115 10km (33k')</para></entry>
406 <entry>TeleMini <?linebreak?>v2.0</entry>
407 <entry><para>MS5607 30km (100k')</para></entry>
413 <entry>3.7-12V</entry>
416 <entry>EasyMini <?linebreak?>v1.0</entry>
417 <entry><para>MS5607 30km (100k')</para></entry>
423 <entry>3.7-12V</entry>
426 <entry>TeleMega <?linebreak?>v1.0</entry>
427 <entry><para>MS5607 30km (100k')</para></entry>
428 <entry><para>MMA6555 102g</para></entry>
429 <entry>uBlox Max-7Q</entry>
430 <entry><para>MPU6000 HMC5883</para></entry>
439 <title>Altus Metrum Boards</title>
440 <?dbfo keep-together="always"?>
441 <tgroup cols='6' align='center' colsep='1' rowsep='1'>
442 <colspec align='center' colwidth='*' colname='Device'/>
443 <colspec align='center' colwidth='*' colname='Connectors'/>
444 <colspec align='center' colwidth='*' colname='Screw Terminals'/>
445 <colspec align='center' colwidth='*' colname='Width'/>
446 <colspec align='center' colwidth='*' colname='Length'/>
447 <colspec align='center' colwidth='*' colname='Tube Size'/>
450 <entry align='center'>Device</entry>
451 <entry align='center'>Connectors</entry>
452 <entry align='center'>Screw Terminals</entry>
453 <entry align='center'>Width</entry>
454 <entry align='center'>Length</entry>
455 <entry align='center'>Tube Size</entry>
460 <entry>TeleMetrum</entry>
464 Companion<?linebreak?>
468 <entry><para>Apogee pyro <?linebreak?>Main pyro <?linebreak?>Switch</para></entry>
469 <entry>1 inch (2.54cm)</entry>
470 <entry>2 ¾ inch (6.99cm)</entry>
471 <entry>29mm coupler</entry>
474 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
481 Apogee pyro <?linebreak?>
484 <entry>½ inch (1.27cm)</entry>
485 <entry>1½ inch (3.81cm)</entry>
486 <entry>18mm airframe</entry>
489 <entry>TeleMini <?linebreak?>v2.0</entry>
497 Apogee pyro <?linebreak?>
498 Main pyro <?linebreak?>
499 Battery <?linebreak?>
502 <entry>0.8 inch (2.03cm)</entry>
503 <entry>1½ inch (3.81cm)</entry>
504 <entry>24mm coupler</entry>
507 <entry>EasyMini</entry>
514 Apogee pyro <?linebreak?>
515 Main pyro <?linebreak?>
516 Battery <?linebreak?>
519 <entry>0.8 inch (2.03cm)</entry>
520 <entry>1½ inch (3.81cm)</entry>
521 <entry>24mm coupler</entry>
524 <entry>TeleMega</entry>
528 Companion<?linebreak?>
533 Apogee pyro <?linebreak?>
534 Main pyro<?linebreak?>
535 Pyro A-D<?linebreak?>
539 <entry>1¼ inch (3.18cm)</entry>
540 <entry>3¼ inch (8.26cm)</entry>
541 <entry>38mm coupler</entry>
548 <title>TeleMetrum</title>
550 TeleMetrum is a 1 inch by 2¾ inch circuit board. It was designed to
551 fit inside coupler for 29mm air-frame tubing, but using it in a tube that
552 small in diameter may require some creativity in mounting and wiring
553 to succeed! The presence of an accelerometer means TeleMetrum should
554 be aligned along the flight axis of the airframe, and by default the ¼
555 wave UHF wire antenna should be on the nose-cone end of the board. The
556 antenna wire is about 7 inches long, and wiring for a power switch and
557 the e-matches for apogee and main ejection charges depart from the
558 fin can end of the board, meaning an ideal “simple” avionics
559 bay for TeleMetrum should have at least 10 inches of interior length.
563 <title>TeleMini</title>
565 TeleMini v1.0 is ½ inches by 1½ inches. It was
566 designed to fit inside an 18mm air-frame tube, but using it in
567 a tube that small in diameter may require some creativity in
568 mounting and wiring to succeed! Since there is no
569 accelerometer, TeleMini can be mounted in any convenient
570 orientation. The default ¼ wave UHF wire antenna attached to
571 the center of one end of the board is about 7 inches long. Two
572 wires for the power switch are connected to holes in the
573 middle of the board. Screw terminals for the e-matches for
574 apogee and main ejection charges depart from the other end of
575 the board, meaning an ideal “simple” avionics bay for TeleMini
576 should have at least 9 inches of interior length.
579 TeleMini v2.0 is 0.8 inches by 1½ inches. It adds more
580 on-board data logging memory, a built-in USB connector and
581 screw terminals for the battery and power switch. The larger
582 board fits in a 24mm coupler. There's also a battery connector
583 for a LiPo battery if you want to use one of those.
587 <title>EasyMini</title>
589 EasyMini is built on a 0.8 inch by 1½ inch circuit board. It's
590 designed to fit in a 24mm coupler tube. The connectors and
591 screw terminals match TeleMini, so you can swap an EasyMini
596 <title>TeleMega</title>
598 TeleMega is a 1¼ inch by 3¼ inch circuit board. It was
599 designed to easily fit in a 38mm coupler. Like TeleMetrum,
600 TeleMega has an accelerometer and so it must be mounted so that
601 the board is aligned with the flight axis. It can be mounted
602 either antenna up or down.
606 <title>Flight Data Recording</title>
608 Each flight computer logs data at 100 samples per second
609 during ascent and 10 samples per second during descent, except
610 for TeleMini v1.0, which records ascent at 10 samples per
611 second and descent at 1 sample per second. Data are logged to
612 an on-board flash memory part, which can be partitioned into
613 several equal-sized blocks, one for each flight.
616 <title>Data Storage on Altus Metrum altimeters</title>
617 <?dbfo keep-together="always"?>
618 <tgroup cols='4' align='center' colsep='1' rowsep='1'>
619 <colspec align='center' colwidth='*' colname='Device'/>
620 <colspec align='center' colwidth='*' colname='Bytes per sample'/>
621 <colspec align='center' colwidth='*' colname='Total storage'/>
622 <colspec align='center' colwidth='*' colname='Minutes of
626 <entry align='center'>Device</entry>
627 <entry align='center'>Bytes per Sample</entry>
628 <entry align='center'>Total Storage</entry>
629 <entry align='center'>Minutes at Full Rate</entry>
634 <entry>TeleMetrum v1.0</entry>
640 <entry>TeleMetrum v1.1 v1.2</entry>
646 <entry>TeleMetrum v2.0</entry>
652 <entry>TeleMini v1.0</entry>
658 <entry>TeleMini v2.0</entry>
664 <entry>EasyMini</entry>
670 <entry>TeleMega</entry>
679 The on-board flash is partitioned into separate flight logs,
680 each of a fixed maximum size. Increase the maximum size of
681 each log and you reduce the number of flights that can be
682 stored. Decrease the size and you can store more flights.
685 Configuration data is also stored in the flash memory on
686 TeleMetrum v1.x, TeleMini and EasyMini. This consumes 64kB
687 of flash space. This configuration space is not available
688 for storing flight log data. TeleMetrum v2.0 and TeleMega
689 store configuration data in a bit of eeprom available within
690 the processor chip, leaving that space available in flash for
694 To compute the amount of space needed for a single flight, you
695 can multiply the expected ascent time (in seconds) by 100
696 times bytes-per-sample, multiply the expected descent time (in
697 seconds) by 10 times the bytes per sample and add the two
698 together. That will slightly under-estimate the storage (in
699 bytes) needed for the flight. For instance, a TeleMetrum v2.0 flight spending
700 20 seconds in ascent and 150 seconds in descent will take
701 about (20 * 1600) + (150 * 160) = 56000 bytes of storage. You
702 could store dozens of these flights in the on-board flash.
705 The default size allows for several flights on each flight
706 computer, except for TeleMini v1.0, which only holds data for a
707 single flight. You can adjust the size.
710 Altus Metrum flight computers will not overwrite existing
711 flight data, so be sure to download flight data and erase it
712 from the flight computer before it fills up. The flight
713 computer will still successfully control the flight even if it
714 cannot log data, so the only thing you will lose is the data.
718 <title>Installation</title>
720 A typical installation involves attaching
721 only a suitable battery, a single pole switch for
722 power on/off, and two pairs of wires connecting e-matches for the
723 apogee and main ejection charges. All Altus Metrum products are
724 designed for use with single-cell batteries with 3.7 volts
725 nominal. TeleMini v2.0 and EasyMini may also be used with other
726 batteries as long as they supply between 4 and 12 volts.
729 The battery connectors are a standard 2-pin JST connector and
730 match batteries sold by Spark Fun. These batteries are
731 single-cell Lithium Polymer batteries that nominally provide 3.7
732 volts. Other vendors sell similar batteries for RC aircraft
733 using mating connectors, however the polarity for those is
734 generally reversed from the batteries used by Altus Metrum
735 products. In particular, the Tenergy batteries supplied for use
736 in Featherweight flight computers are not compatible with Altus
737 Metrum flight computers or battery chargers. <emphasis>Check
738 polarity and voltage before connecting any battery not purchased
739 from Altus Metrum or Spark Fun.</emphasis>
742 By default, we use the unregulated output of the battery directly
743 to fire ejection charges. This works marvelously with standard
744 low-current e-matches like the J-Tek from MJG Technologies, and with
745 Quest Q2G2 igniters. However, if you want or need to use a separate
746 pyro battery, check out the “External Pyro Battery” section in this
747 manual for instructions on how to wire that up. The altimeters are
748 designed to work with an external pyro battery of no more than 15 volts.
752 Ejection charges are wired directly to the screw terminal block
753 at the aft end of the altimeter. You'll need a very small straight
754 blade screwdriver for these screws, such as you might find in a
755 jeweler's screwdriver set.
758 Except for TeleMini v1.0, the flight computers also use the
759 screw terminal block for the power switch leads. On TeleMini v1.0,
760 the power switch leads are soldered directly to the board and
761 can be connected directly to a switch.
764 For most air-frames, the integrated antennas are more than
765 adequate. However, if you are installing in a carbon-fiber or
766 metal electronics bay which is opaque to RF signals, you may need to
767 use off-board external antennas instead. In this case, you can
768 order an altimeter with an SMA connector for the UHF antenna
769 connection, and, on TeleMetrum v1, you can unplug the integrated GPS
770 antenna and select an appropriate off-board GPS antenna with
771 cable terminating in a U.FL connector.
776 <title>System Operation</title>
778 <title>Firmware Modes </title>
780 The AltOS firmware build for the altimeters has two
781 fundamental modes, “idle” and “flight”. Which of these modes
782 the firmware operates in is determined at start up time. For
783 TeleMetrum, the mode is controlled by the orientation of the
784 rocket (well, actually the board, of course...) at the time
785 power is switched on. If the rocket is “nose up”, then
786 TeleMetrum assumes it's on a rail or rod being prepared for
787 launch, so the firmware chooses flight mode. However, if the
788 rocket is more or less horizontal, the firmware instead enters
789 idle mode. Since TeleMini v2.0 and EasyMini don't have an
790 accelerometer we can use to determine orientation, “idle” mode
791 is selected if the board is connected via USB to a computer,
792 otherwise the board enters “flight” mode. TeleMini v1.0
793 selects “idle” mode if it receives a command packet within the
794 first five seconds of operation.
797 At power on, you will hear three beeps or see three flashes
798 (“S” in Morse code for start up) and then a pause while
799 the altimeter completes initialization and self test, and decides
800 which mode to enter next.
803 In flight or “pad” mode, the altimeter engages the flight
804 state machine, goes into transmit-only mode to
805 send telemetry, and waits for launch to be detected.
806 Flight mode is indicated by an “di-dah-dah-dit” (“P” for pad)
807 on the beeper or lights, followed by beeps or flashes
808 indicating the state of the pyrotechnic igniter continuity.
809 One beep/flash indicates apogee continuity, two beeps/flashes
810 indicate main continuity, three beeps/flashes indicate both
811 apogee and main continuity, and one longer “brap” sound or
812 rapidly alternating lights indicates no continuity. For a
813 dual deploy flight, make sure you're getting three beeps or
814 flashes before launching! For apogee-only or motor eject
815 flights, do what makes sense.
818 If idle mode is entered, you will hear an audible “di-dit” or
819 see two short flashes (“I” for idle), and the flight state
820 machine is disengaged, thus no ejection charges will fire.
821 The altimeters also listen for the radio link when in idle
822 mode for requests sent via TeleDongle. Commands can be issued
823 in idle mode over either USB or the radio link
824 equivalently. TeleMini v1.0 only has the radio link. Idle
825 mode is useful for configuring the altimeter, for extracting
826 data from the on-board storage chip after flight, and for
827 ground testing pyro charges.
830 One “neat trick” of particular value when TeleMetrum or TeleMega are used with
831 very large air-frames, is that you can power the board up while the
832 rocket is horizontal, such that it comes up in idle mode. Then you can
833 raise the air-frame to launch position, and issue a 'reset' command
834 via TeleDongle over the radio link to cause the altimeter to reboot and
835 come up in flight mode. This is much safer than standing on the top
836 step of a rickety step-ladder or hanging off the side of a launch
837 tower with a screw-driver trying to turn on your avionics before
841 TeleMini v1.0 is configured solely via the radio link. Of course, that
842 means you need to know the TeleMini radio configuration values
843 or you won't be able to communicate with it. For situations
844 when you don't have the radio configuration values, TeleMini v1.0
845 offers an 'emergency recovery' mode. In this mode, TeleMini is
846 configured as follows:
850 Sets the radio frequency to 434.550MHz
855 Sets the radio calibration back to the factory value.
860 Sets the callsign to N0CALL
865 Does not go to 'pad' mode after five seconds.
871 To get into 'emergency recovery' mode, first find the row of
872 four small holes opposite the switch wiring. Using a short
873 piece of small gauge wire, connect the outer two holes
874 together, then power TeleMini up. Once the red LED is lit,
875 disconnect the wire and the board should signal that it's in
876 'idle' mode after the initial five second startup period.
882 TeleMetrum and TeleMega include a complete GPS receiver. A
883 complete explanation of how GPS works is beyond the scope of
884 this manual, but the bottom line is that the GPS receiver
885 needs to lock onto at least four satellites to obtain a solid
886 3 dimensional position fix and know what time it is.
889 The flight computers provide backup power to the GPS chip any time a
890 battery is connected. This allows the receiver to “warm start” on
891 the launch rail much faster than if every power-on were a GPS
892 “cold start”. In typical operations, powering up
893 on the flight line in idle mode while performing final air-frame
894 preparation will be sufficient to allow the GPS receiver to cold
895 start and acquire lock. Then the board can be powered down during
896 RSO review and installation on a launch rod or rail. When the board
897 is turned back on, the GPS system should lock very quickly, typically
898 long before igniter installation and return to the flight line are
903 <title>Controlling An Altimeter Over The Radio Link</title>
905 One of the unique features of the Altus Metrum system is the
906 ability to create a two way command link between TeleDongle
907 and an altimeter using the digital radio transceivers
908 built into each device. This allows you to interact with the
909 altimeter from afar, as if it were directly connected to the
913 Any operation which can be performed with a flight computer can
914 either be done with the device directly connected to the
915 computer via the USB cable, or through the radio
916 link. TeleMini v1.0 doesn't provide a USB connector and so it is
917 always communicated with over radio. Select the appropriate
918 TeleDongle device when the list of devices is presented and
919 AltosUI will interact with an altimeter over the radio link.
922 One oddity in the current interface is how AltosUI selects the
923 frequency for radio communications. Instead of providing
924 an interface to specifically configure the frequency, it uses
925 whatever frequency was most recently selected for the target
926 TeleDongle device in Monitor Flight mode. If you haven't ever
927 used that mode with the TeleDongle in question, select the
928 Monitor Flight button from the top level UI, and pick the
929 appropriate TeleDongle device. Once the flight monitoring
930 window is open, select the desired frequency and then close it
931 down again. All radio communications will now use that frequency.
936 Save Flight Data—Recover flight data from the rocket without
942 Configure altimeter apogee delays, main deploy heights
943 and additional pyro event conditions
944 to respond to changing launch conditions. You can also
945 'reboot' the altimeter. Use this to remotely enable the
946 flight computer by turning TeleMetrum or TeleMega on in “idle” mode,
947 then once the air-frame is oriented for launch, you can
948 reboot the altimeter and have it restart in pad mode
949 without having to climb the scary ladder.
954 Fire Igniters—Test your deployment charges without snaking
955 wires out through holes in the air-frame. Simply assemble the
956 rocket as if for flight with the apogee and main charges
957 loaded, then remotely command the altimeter to fire the
963 Operation over the radio link for configuring an altimeter, ground
964 testing igniters, and so forth uses the same RF frequencies as flight
965 telemetry. To configure the desired TeleDongle frequency, select
966 the monitor flight tab, then use the frequency selector and
967 close the window before performing other desired radio operations.
970 The flight computers only enable radio commanding in 'idle' mode.
971 TeleMetrum and TeleMega use the accelerometer to detect which orientation they
972 start up in, so make sure you have the flight computer lying horizontally when you turn
973 it on. Otherwise, it will start in 'pad' mode ready for
974 flight, and will not be listening for command packets from TeleDongle.
977 TeleMini listens for a command packet for five seconds after
978 first being turned on, if it doesn't hear anything, it enters
979 'pad' mode, ready for flight and will no longer listen for
980 command packets. The easiest way to connect to TeleMini is to
981 initiate the command and select the TeleDongle device. At this
982 point, the TeleDongle will be attempting to communicate with
983 the TeleMini. Now turn TeleMini on, and it should immediately
984 start communicating with the TeleDongle and the desired
985 operation can be performed.
988 You can monitor the operation of the radio link by watching the
989 lights on the devices. The red LED will flash each time a packet
990 is transmitted, while the green LED will light up on TeleDongle when
991 it is waiting to receive a packet from the altimeter.
995 <title>Ground Testing </title>
997 An important aspect of preparing a rocket using electronic deployment
998 for flight is ground testing the recovery system. Thanks
999 to the bi-directional radio link central to the Altus Metrum system,
1000 this can be accomplished in a TeleMega, TeleMetrum or TeleMini equipped rocket
1001 with less work than you may be accustomed to with other systems. It
1005 Just prep the rocket for flight, then power up the altimeter
1006 in “idle” mode (placing air-frame horizontal for TeleMetrum or TeleMega, or
1007 selecting the Configure Altimeter tab for TeleMini). This will cause
1008 the firmware to go into “idle” mode, in which the normal flight
1009 state machine is disabled and charges will not fire without
1010 manual command. You can now command the altimeter to fire the apogee
1011 or main charges from a safe distance using your computer and
1012 TeleDongle and the Fire Igniter tab to complete ejection testing.
1016 <title>Radio Link </title>
1018 The chip our boards are based on incorporates an RF transceiver, but
1019 it's not a full duplex system... each end can only be transmitting or
1020 receiving at any given moment. So we had to decide how to manage the
1024 By design, the altimeter firmware listens for the radio link when
1025 it's in “idle mode”, which
1026 allows us to use the radio link to configure the rocket, do things like
1027 ejection tests, and extract data after a flight without having to
1028 crack open the air-frame. However, when the board is in “flight
1029 mode”, the altimeter only
1030 transmits and doesn't listen at all. That's because we want to put
1031 ultimate priority on event detection and getting telemetry out of
1033 the radio in case the rocket crashes and we aren't able to extract
1037 We don't generally use a 'normal packet radio' mode like APRS
1038 because they're just too inefficient. The GFSK modulation we
1039 use is FSK with the base-band pulses passed through a Gaussian
1040 filter before they go into the modulator to limit the
1041 transmitted bandwidth. When combined with forward error
1042 correction and interleaving, this allows us to have a very
1043 robust 19.2 kilobit data link with only 10-40 milliwatts of
1044 transmit power, a whip antenna in the rocket, and a hand-held
1045 Yagi on the ground. We've had flights to above 21k feet AGL
1046 with great reception, and calculations suggest we should be
1047 good to well over 40k feet AGL with a 5-element yagi on the
1048 ground with our 10mW units and over 100k feet AGL with the
1049 40mW devices. We hope to fly boards to higher altitudes over
1050 time, and would of course appreciate customer feedback on
1051 performance in higher altitude flights!
1054 TeleMetrum v2.0 and TeleMega can send APRS if desired, the
1055 interval between APRS packets can be configured. As each APRS
1056 packet takes a full second to transmit, we recommend an
1057 interval of at least 5 seconds to avoid consuming too much
1058 battery power or radio channel bandwidth.
1062 <title>Configurable Parameters</title>
1064 Configuring an Altus Metrum altimeter for flight is very
1065 simple. Even on our baro-only TeleMini and EasyMini boards, the use of a Kalman
1066 filter means there is no need to set a “mach delay”. The few
1067 configurable parameters can all be set using AltosUI over USB or
1068 or radio link via TeleDongle.
1071 <title>Radio Frequency</title>
1073 Altus Metrum boards support radio frequencies in the 70cm
1074 band. By default, the configuration interface provides a
1075 list of 10 “standard” frequencies in 100kHz channels starting at
1076 434.550MHz. However, the firmware supports use of
1077 any 50kHz multiple within the 70cm band. At any given
1078 launch, we highly recommend coordinating when and by whom each
1079 frequency will be used to avoid interference. And of course, both
1080 altimeter and TeleDongle must be configured to the same
1081 frequency to successfully communicate with each other.
1085 <title>Apogee Delay</title>
1087 Apogee delay is the number of seconds after the altimeter detects flight
1088 apogee that the drogue charge should be fired. In most cases, this
1089 should be left at the default of 0. However, if you are flying
1090 redundant electronics such as for an L3 certification, you may wish
1091 to set one of your altimeters to a positive delay so that both
1092 primary and backup pyrotechnic charges do not fire simultaneously.
1095 The Altus Metrum apogee detection algorithm fires exactly at
1096 apogee. If you are also flying an altimeter like the
1097 PerfectFlite MAWD, which only supports selecting 0 or 1
1098 seconds of apogee delay, you may wish to set the MAWD to 0
1099 seconds delay and set the TeleMetrum to fire your backup 2
1100 or 3 seconds later to avoid any chance of both charges
1101 firing simultaneously. We've flown several air-frames this
1102 way quite happily, including Keith's successful L3 cert.
1106 <title>Main Deployment Altitude</title>
1108 By default, the altimeter will fire the main deployment charge at an
1109 elevation of 250 meters (about 820 feet) above ground. We think this
1110 is a good elevation for most air-frames, but feel free to change this
1111 to suit. In particular, if you are flying two altimeters, you may
1113 deployment elevation for the backup altimeter to be something lower
1114 than the primary so that both pyrotechnic charges don't fire
1119 <title>Maximum Flight Log</title>
1121 Changing this value will set the maximum amount of flight
1122 log storage that an individual flight will use. The
1123 available storage is divided into as many flights of the
1124 specified size as can fit in the available space. You can
1125 download and erase individual flight logs. If you fill up
1126 the available storage, future flights will not get logged
1127 until you erase some of the stored ones.
1131 <title>Ignite Mode</title>
1133 Instead of firing one charge at apogee and another charge at
1134 a fixed height above the ground, you can configure the
1135 altimeter to fire both at apogee or both during
1136 descent. This was added to support an airframe that has two
1137 altimeters, one in the fin can and one in the
1141 Providing the ability to use both igniters for apogee or
1142 main allows some level of redundancy without needing two
1143 flight computers. In Redundant Apogee or Redundant Main
1144 mode, the two charges will be fired two seconds apart.
1148 <title>Pad Orientation</title>
1150 TeleMetrum and TeleMega measure acceleration along the axis
1151 of the board. Which way the board is oriented affects the
1152 sign of the acceleration value. Instead of trying to guess
1153 which way the board is mounted in the air frame, the
1154 altimeter must be explicitly configured for either Antenna
1155 Up or Antenna Down. The default, Antenna Up, expects the end
1156 of the board connected to the 70cm antenna to be nearest the
1157 nose of the rocket, with the end containing the screw
1158 terminals nearest the tail.
1162 <title>Pyro Channels</title>
1164 In addition to the usual Apogee and Main pyro channels,
1165 TeleMega has four additional channels that can be configured
1166 to activate when various flight conditions are
1167 satisfied. You can select as many conditions as necessary;
1168 all of them must be met in order to activate the
1169 channel. The conditions available are:
1174 Acceleration away from the ground. Select a value, and
1175 then choose whether acceleration should be above or
1176 below that value. Acceleration is positive upwards, so
1177 accelerating towards the ground would produce negative
1178 numbers. Acceleration during descent is noisy and
1179 inaccurate, so be careful when using it during these
1180 phases of the flight.
1185 Vertical speed. Select a value, and then choose whether
1186 vertical speed should be above or below that
1187 value. Speed is positive upwards, so moving towards the
1188 ground would produce negative numbers. Speed during
1189 descent is a bit noisy and so be careful when using it
1190 during these phases of the flight.
1195 Height. Select a value, and then choose whether the
1196 height above the launch pad should be above or below
1202 Orientation. TeleMega contains a 3-axis gyroscope and
1203 accelerometer which is used to measure the current
1204 angle. Note that this angle is not the change in angle
1205 from the launch pad, but rather absolute relative to
1206 gravity; the 3-axis accelerometer is used to compute the
1207 angle of the rocket on the launch pad and initialize the
1208 system. Because this value is computed by integrating
1209 rate gyros, it gets progressively less accurate as the
1210 flight goes on. It should have an accumulated error of
1211 less than .2°/second (after 10 seconds of flight, the
1212 error should be less than 2°).
1215 The usual use of the orientation configuration is to
1216 ensure that the rocket is traveling mostly upwards when
1217 deciding whether to ignite air starts or additional
1218 stages. For that, choose a reasonable maximum angle
1219 (like 20°) and set the motor igniter to require an angle
1220 of less than that value.
1225 Flight Time. Time since boost was detected. Select a
1226 value and choose whether to activate the pyro channel
1227 before or after that amount of time.
1232 Ascending. A simple test saying whether the rocket is
1233 going up or not. This is exactly equivalent to testing
1234 whether the speed is > 0.
1239 Descending. A simple test saying whether the rocket is
1240 going down or not. This is exactly equivalent to testing
1241 whether the speed is < 0.
1246 After Motor. The flight software counts each time the
1247 rocket starts accelerating (presumably due to a motor or
1248 motors igniting). Use this value to count ignitions for
1249 multi-staged or multi-airstart launches.
1254 Delay. This value doesn't perform any checks, instead it
1255 inserts a delay between the time when the other
1256 parameters become true and when the pyro channel is
1262 Flight State. The flight software tracks the flight
1263 through a sequence of states:
1267 Boost. The motor has lit and the rocket is
1268 accelerating upwards.
1273 Fast. The motor has burned out and the rocket is
1274 descellerating, but it is going faster than 200m/s.
1279 Coast. The rocket is still moving upwards and
1280 decelerating, but the speed is less than 200m/s.
1285 Drogue. The rocket has reached apogee and is heading
1286 back down, but is above the configured Main
1292 Main. The rocket is still descending, and is below
1298 Landed. The rocket is no longer moving.
1304 You can select a state to limit when the pyro channel
1305 may activate; note that the check is based on when the
1306 rocket transitions <emphasis>into</emphasis> the state, and so checking for
1307 “greater than Boost” means that the rocket is currently
1308 in boost or some later state.
1311 When a motor burns out, the rocket enters either Fast or
1312 Coast state (depending on how fast it is moving). If the
1313 computer detects upwards acceleration again, it will
1314 move back to Boost state.
1324 <title>AltosUI</title>
1326 The AltosUI program provides a graphical user interface for
1327 interacting with the Altus Metrum product family. AltosUI can
1328 monitor telemetry data, configure devices and many other
1329 tasks. The primary interface window provides a selection of
1330 buttons, one for each major activity in the system. This manual
1331 is split into chapters, each of which documents one of the tasks
1332 provided from the top-level toolbar.
1335 <title>Monitor Flight</title>
1336 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
1338 Selecting this item brings up a dialog box listing all of the
1339 connected TeleDongle devices. When you choose one of these,
1340 AltosUI will create a window to display telemetry data as
1341 received by the selected TeleDongle device.
1344 All telemetry data received are automatically recorded in
1345 suitable log files. The name of the files includes the current
1346 date and rocket serial and flight numbers.
1349 The radio frequency being monitored by the TeleDongle device is
1350 displayed at the top of the window. You can configure the
1351 frequency by clicking on the frequency box and selecting the desired
1352 frequency. AltosUI remembers the last frequency selected for each
1353 TeleDongle and selects that automatically the next time you use
1357 Below the TeleDongle frequency selector, the window contains a few
1358 significant pieces of information about the altimeter providing
1359 the telemetry data stream:
1363 <para>The configured call-sign</para>
1366 <para>The device serial number</para>
1369 <para>The flight number. Each altimeter remembers how many
1375 The rocket flight state. Each flight passes through several
1376 states including Pad, Boost, Fast, Coast, Drogue, Main and
1382 The Received Signal Strength Indicator value. This lets
1383 you know how strong a signal TeleDongle is receiving. The
1384 radio inside TeleDongle operates down to about -99dBm;
1385 weaker signals may not be receivable. The packet link uses
1386 error detection and correction techniques which prevent
1387 incorrect data from being reported.
1392 The age of the displayed data, in seconds since the last
1393 successfully received telemetry packet. In normal operation
1394 this will stay in the low single digits. If the number starts
1395 counting up, then you are no longer receiving data over the radio
1396 link from the flight computer.
1401 Finally, the largest portion of the window contains a set of
1402 tabs, each of which contain some information about the rocket.
1403 They're arranged in 'flight order' so that as the flight
1404 progresses, the selected tab automatically switches to display
1405 data relevant to the current state of the flight. You can select
1406 other tabs at any time. The final 'table' tab displays all of
1407 the raw telemetry values in one place in a spreadsheet-like format.
1410 <title>Launch Pad</title>
1412 The 'Launch Pad' tab shows information used to decide when the
1413 rocket is ready for flight. The first elements include red/green
1414 indicators, if any of these is red, you'll want to evaluate
1415 whether the rocket is ready to launch:
1418 <term>Battery Voltage</term>
1421 This indicates whether the Li-Po battery
1422 powering the TeleMetrum has sufficient charge to last for
1423 the duration of the flight. A value of more than
1424 3.8V is required for a 'GO' status.
1429 <term>Apogee Igniter Voltage</term>
1432 This indicates whether the apogee
1433 igniter has continuity. If the igniter has a low
1434 resistance, then the voltage measured here will be close
1435 to the Li-Po battery voltage. A value greater than 3.2V is
1436 required for a 'GO' status.
1441 <term>Main Igniter Voltage</term>
1444 This indicates whether the main
1445 igniter has continuity. If the igniter has a low
1446 resistance, then the voltage measured here will be close
1447 to the Li-Po battery voltage. A value greater than 3.2V is
1448 required for a 'GO' status.
1453 <term>On-board Data Logging</term>
1456 This indicates whether there is
1457 space remaining on-board to store flight data for the
1458 upcoming flight. If you've downloaded data, but failed
1459 to erase flights, there may not be any space
1460 left. TeleMetrum can store multiple flights, depending
1461 on the configured maximum flight log size. TeleMini
1462 stores only a single flight, so it will need to be
1463 downloaded and erased after each flight to capture
1464 data. This only affects on-board flight logging; the
1465 altimeter will still transmit telemetry and fire
1466 ejection charges at the proper times.
1471 <term>GPS Locked</term>
1474 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
1475 currently able to compute position information. GPS requires
1476 at least 4 satellites to compute an accurate position.
1481 <term>GPS Ready</term>
1484 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
1485 10 consecutive positions without losing lock. This ensures
1486 that the GPS receiver has reliable reception from the
1494 The Launchpad tab also shows the computed launch pad position
1495 and altitude, averaging many reported positions to improve the
1496 accuracy of the fix.
1500 <title>Ascent</title>
1502 This tab is shown during Boost, Fast and Coast
1503 phases. The information displayed here helps monitor the
1504 rocket as it heads towards apogee.
1507 The height, speed and acceleration are shown along with the
1508 maximum values for each of them. This allows you to quickly
1509 answer the most commonly asked questions you'll hear during
1513 The current latitude and longitude reported by the TeleMetrum GPS are
1514 also shown. Note that under high acceleration, these values
1515 may not get updated as the GPS receiver loses position
1516 fix. Once the rocket starts coasting, the receiver should
1517 start reporting position again.
1520 Finally, the current igniter voltages are reported as in the
1521 Launch Pad tab. This can help diagnose deployment failures
1522 caused by wiring which comes loose under high acceleration.
1526 <title>Descent</title>
1528 Once the rocket has reached apogee and (we hope) activated the
1529 apogee charge, attention switches to tracking the rocket on
1530 the way back to the ground, and for dual-deploy flights,
1531 waiting for the main charge to fire.
1534 To monitor whether the apogee charge operated correctly, the
1535 current descent rate is reported along with the current
1536 height. Good descent rates vary based on the choice of recovery
1537 components, but generally range from 15-30m/s on drogue and should
1538 be below 10m/s when under the main parachute in a dual-deploy flight.
1541 For TeleMetrum altimeters, you can locate the rocket in the
1542 sky using the elevation and bearing information to figure
1543 out where to look. Elevation is in degrees above the
1544 horizon. Bearing is reported in degrees relative to true
1545 north. Range can help figure out how big the rocket will
1546 appear. Ground Distance shows how far it is to a point
1547 directly under the rocket and can help figure out where the
1548 rocket is likely to land. Note that all of these values are
1549 relative to the pad location. If the elevation is near 90°,
1550 the rocket is over the pad, not over you.
1553 Finally, the igniter voltages are reported in this tab as
1554 well, both to monitor the main charge as well as to see what
1555 the status of the apogee charge is. Note that some commercial
1556 e-matches are designed to retain continuity even after being
1557 fired, and will continue to show as green or return from red to
1562 <title>Landed</title>
1564 Once the rocket is on the ground, attention switches to
1565 recovery. While the radio signal is often lost once the
1566 rocket is on the ground, the last reported GPS position is
1567 generally within a short distance of the actual landing location.
1570 The last reported GPS position is reported both by
1571 latitude and longitude as well as a bearing and distance from
1572 the launch pad. The distance should give you a good idea of
1573 whether to walk or hitch a ride. Take the reported
1574 latitude and longitude and enter them into your hand-held GPS
1575 unit and have that compute a track to the landing location.
1578 Both TeleMini and TeleMetrum will continue to transmit RDF
1579 tones after landing, allowing you to locate the rocket by
1580 following the radio signal if necessary. You may need to get
1581 away from the clutter of the flight line, or even get up on
1582 a hill (or your neighbor's RV roof) to receive the RDF signal.
1585 The maximum height, speed and acceleration reported
1586 during the flight are displayed for your admiring observers.
1587 The accuracy of these immediate values depends on the quality
1588 of your radio link and how many packets were received.
1589 Recovering the on-board data after flight will likely yield
1590 more precise results.
1593 To get more detailed information about the flight, you can
1594 click on the 'Graph Flight' button which will bring up a
1595 graph window for the current flight.
1599 <title>Site Map</title>
1601 When the TeleMetrum has a GPS fix, the Site Map tab will map
1602 the rocket's position to make it easier for you to locate the
1603 rocket, both while it is in the air, and when it has landed. The
1604 rocket's state is indicated by color: white for pad, red for
1605 boost, pink for fast, yellow for coast, light blue for drogue,
1606 dark blue for main, and black for landed.
1609 The map's scale is approximately 3m (10ft) per pixel. The map
1610 can be dragged using the left mouse button. The map will attempt
1611 to keep the rocket roughly centered while data is being received.
1614 Images are fetched automatically via the Google Maps Static API,
1615 and cached on disk for reuse. If map images cannot be downloaded,
1616 the rocket's path will be traced on a dark gray background
1620 You can pre-load images for your favorite launch sites
1621 before you leave home; check out the 'Preload Maps' section below.
1626 <title>Save Flight Data</title>
1628 The altimeter records flight data to its internal flash memory.
1629 TeleMetrum data is recorded at a much higher rate than the telemetry
1630 system can handle, and is not subject to radio drop-outs. As
1631 such, it provides a more complete and precise record of the
1632 flight. The 'Save Flight Data' button allows you to read the
1633 flash memory and write it to disk. As TeleMini has only a barometer, it
1634 records data at the same rate as the telemetry signal, but there will be
1635 no data lost due to telemetry drop-outs.
1638 Clicking on the 'Save Flight Data' button brings up a list of
1639 connected TeleMetrum and TeleDongle devices. If you select a
1640 TeleMetrum device, the flight data will be downloaded from that
1641 device directly. If you select a TeleDongle device, flight data
1642 will be downloaded from an altimeter over radio link via the
1643 specified TeleDongle. See the chapter on Controlling An Altimeter
1644 Over The Radio Link for more information.
1647 After the device has been selected, a dialog showing the
1648 flight data saved in the device will be shown allowing you to
1649 select which flights to download and which to delete. With
1650 version 0.9 or newer firmware, you must erase flights in order
1651 for the space they consume to be reused by another
1652 flight. This prevents accidentally losing flight data
1653 if you neglect to download data before flying again. Note that
1654 if there is no more space available in the device, then no
1655 data will be recorded during the next flight.
1658 The file name for each flight log is computed automatically
1659 from the recorded flight date, altimeter serial number and
1660 flight number information.
1664 <title>Replay Flight</title>
1666 Select this button and you are prompted to select a flight
1667 record file, either a .telem file recording telemetry data or a
1668 .eeprom file containing flight data saved from the altimeter
1672 Once a flight record is selected, the flight monitor interface
1673 is displayed and the flight is re-enacted in real time. Check
1674 the Monitor Flight chapter above to learn how this window operates.
1678 <title>Graph Data</title>
1680 Select this button and you are prompted to select a flight
1681 record file, either a .telem file recording telemetry data or a
1682 .eeprom file containing flight data saved from
1686 Once a flight record is selected, a window with multiple tabs is
1690 <term>Flight Graph</term>
1693 By default, the graph contains acceleration (blue),
1694 velocity (green) and altitude (red).
1699 <term>Configure Graph</term>
1702 This selects which graph elements to show, and, at the
1703 very bottom, lets you switch between metric and
1709 <term>Flight Statistics</term>
1712 Shows overall data computed from the flight.
1720 Shows a satellite image of the flight area overlaid
1721 with the path of the flight. The red concentric
1722 circles mark the launch pad, the black concentric
1723 circles mark the landing location.
1730 The graph can be zoomed into a particular area by clicking and
1731 dragging down and to the right. Once zoomed, the graph can be
1732 reset by clicking and dragging up and to the left. Holding down
1733 control and clicking and dragging allows the graph to be panned.
1734 The right mouse button causes a pop-up menu to be displayed, giving
1735 you the option save or print the plot.
1738 Note that telemetry files will generally produce poor graphs
1739 due to the lower sampling rate and missed telemetry packets.
1740 Use saved flight data in .eeprom files for graphing where possible.
1744 <title>Export Data</title>
1746 This tool takes the raw data files and makes them available for
1747 external analysis. When you select this button, you are prompted to
1749 data file (either .eeprom or .telem will do, remember that
1750 .eeprom files contain higher resolution and more continuous
1751 data). Next, a second dialog appears which is used to select
1752 where to write the resulting file. It has a selector to choose
1753 between CSV and KML file formats.
1756 <title>Comma Separated Value Format</title>
1758 This is a text file containing the data in a form suitable for
1759 import into a spreadsheet or other external data analysis
1760 tool. The first few lines of the file contain the version and
1761 configuration information from the altimeter, then
1762 there is a single header line which labels all of the
1763 fields. All of these lines start with a '#' character which
1764 many tools can be configured to skip over.
1767 The remaining lines of the file contain the data, with each
1768 field separated by a comma and at least one space. All of
1769 the sensor values are converted to standard units, with the
1770 barometric data reported in both pressure, altitude and
1771 height above pad units.
1775 <title>Keyhole Markup Language (for Google Earth)</title>
1777 This is the format used by Google Earth to provide an overlay
1778 within that application. With this, you can use Google Earth to
1779 see the whole flight path in 3D.
1784 <title>Configure Altimeter</title>
1786 Select this button and then select either an altimeter or
1787 TeleDongle Device from the list provided. Selecting a TeleDongle
1788 device will use the radio link to configure a remote altimeter.
1791 The first few lines of the dialog provide information about the
1792 connected device, including the product name,
1793 software version and hardware serial number. Below that are the
1794 individual configuration entries.
1797 At the bottom of the dialog, there are four buttons:
1804 This writes any changes to the
1805 configuration parameter block in flash memory. If you don't
1806 press this button, any changes you make will be lost.
1814 This resets the dialog to the most recently saved values,
1815 erasing any changes you have made.
1823 This reboots the device. Use this to
1824 switch from idle to pad mode by rebooting once the rocket is
1825 oriented for flight, or to confirm changes you think you saved
1834 This closes the dialog. Any unsaved changes will be
1841 The rest of the dialog contains the parameters to be configured.
1844 <title>Main Deploy Altitude</title>
1846 This sets the altitude (above the recorded pad altitude) at
1847 which the 'main' igniter will fire. The drop-down menu shows
1848 some common values, but you can edit the text directly and
1849 choose whatever you like. If the apogee charge fires below
1850 this altitude, then the main charge will fire two seconds
1851 after the apogee charge fires.
1855 <title>Apogee Delay</title>
1857 When flying redundant electronics, it's often important to
1858 ensure that multiple apogee charges don't fire at precisely
1859 the same time, as that can over pressurize the apogee deployment
1860 bay and cause a structural failure of the air-frame. The Apogee
1861 Delay parameter tells the flight computer to fire the apogee
1862 charge a certain number of seconds after apogee has been
1867 <title>Radio Frequency</title>
1869 This configures which of the frequencies to use for both
1870 telemetry and packet command mode. Note that if you set this
1871 value via packet command mode, the TeleDongle frequency will
1872 also be automatically reconfigured to match so that
1873 communication will continue afterwards.
1877 <title>RF Calibration</title>
1879 The radios in every Altus Metrum device are calibrated at the
1880 factory to ensure that they transmit and receive on the
1881 specified frequency. If you need to you can adjust the calibration
1882 by changing this value. Do not do this without understanding what
1883 the value means, read the appendix on calibration and/or the source
1884 code for more information. To change a TeleDongle's calibration,
1885 you must reprogram the unit completely.
1889 <title>Telemetry/RDF/APRS Enable</title>
1891 Enables the radio for transmission during flight. When
1892 disabled, the radio will not transmit anything during flight
1897 <title>APRS Interval</title>
1899 How often to transmit GPS information via APRS. This option
1900 is available on TeleMetrum v2 and TeleMega
1901 boards. TeleMetrum v1 boards cannot transmit APRS
1902 packets. Note that a single APRS packet takes nearly a full
1903 second to transmit, so enabling this option will prevent
1904 sending any other telemetry during that time.
1908 <title>Callsign</title>
1910 This sets the call sign included in each telemetry packet. Set this
1911 as needed to conform to your local radio regulations.
1915 <title>Maximum Flight Log Size</title>
1917 This sets the space (in kilobytes) allocated for each flight
1918 log. The available space will be divided into chunks of this
1919 size. A smaller value will allow more flights to be stored,
1920 a larger value will record data from longer flights.
1924 <title>Ignite Mode</title>
1926 TeleMetrum and TeleMini provide two igniter channels as they
1927 were originally designed as dual-deploy flight
1928 computers. This configuration parameter allows the two
1929 channels to be used in different configurations.
1933 <term>Dual Deploy</term>
1936 This is the usual mode of operation; the
1937 'apogee' channel is fired at apogee and the 'main'
1938 channel at the height above ground specified by the
1939 'Main Deploy Altitude' during descent.
1944 <term>Redundant Apogee</term>
1947 This fires both channels at
1948 apogee, the 'apogee' channel first followed after a two second
1949 delay by the 'main' channel.
1954 <term>Redundant Main</term>
1957 This fires both channels at the
1958 height above ground specified by the Main Deploy
1959 Altitude setting during descent. The 'apogee'
1960 channel is fired first, followed after a two second
1961 delay by the 'main' channel.
1968 <title>Pad Orientation</title>
1970 Because it includes an accelerometer, TeleMetrum and
1971 TeleMega are sensitive to the orientation of the board. By
1972 default, it expects the antenna end to point forward. This
1973 parameter allows that default to be changed, permitting the
1974 board to be mounted with the antenna pointing aft instead.
1978 <term>Antenna Up</term>
1981 In this mode, the antenna end of the
1982 TeleMetrum board must point forward, in line with the
1983 expected flight path.
1988 <term>Antenna Down</term>
1991 In this mode, the antenna end of the
1992 TeleMetrum board must point aft, in line with the
1993 expected flight path.
2000 <title>Configure Pyro Channels</title>
2002 This opens a separate window to configure the additional
2003 pyro channels available on TeleMega. One column is
2004 presented for each channel. Each row represents a single
2005 parameter, if enabled the parameter must meet the specified
2006 test for the pyro channel to be fired. See the Pyro Channels
2007 section in the System Operation chapter above for a
2008 description of these parameters.
2011 Select conditions and set the related value; the pyro
2012 channel will be activated when <emphasis>all</emphasis> of the
2013 conditions are met. Each pyro channel has a separate set of
2014 configuration values, so you can use different values for
2015 the same condition with different channels.
2018 Once you have selected the appropriate configuration for all
2019 of the necessary pyro channels, you can save the pyro
2020 configuration along with the rest of the flight computer
2021 configuration by pressing the 'Save' button in the main
2022 Configure Flight Computer window.
2027 <title>Configure AltosUI</title>
2029 This button presents a dialog so that you can configure the AltosUI global settings.
2032 <title>Voice Settings</title>
2034 AltosUI provides voice announcements during flight so that you
2035 can keep your eyes on the sky and still get information about
2036 the current flight status. However, sometimes you don't want
2041 <para>Enable—turns all voice announcements on and off</para>
2045 Test Voice—Plays a short message allowing you to verify
2046 that the audio system is working and the volume settings
2053 <title>Log Directory</title>
2055 AltosUI logs all telemetry data and saves all TeleMetrum flash
2056 data to this directory. This directory is also used as the
2057 staring point when selecting data files for display or export.
2060 Click on the directory name to bring up a directory choosing
2061 dialog, select a new directory and click 'Select Directory' to
2062 change where AltosUI reads and writes data files.
2066 <title>Callsign</title>
2068 This value is transmitted in each command packet sent from
2069 TeleDongle and received from an altimeter. It is not used in
2070 telemetry mode, as the callsign configured in the altimeter board
2071 is included in all telemetry packets. Configure this
2072 with the AltosUI operators call sign as needed to comply with
2073 your local radio regulations.
2076 Note that to successfully command a flight computer over the radio
2077 (to configure the altimeter, monitor idle, or fire pyro charges),
2078 the callsign configured here must exactly match the callsign
2079 configured in the flight computer. This matching is case
2084 <title>Imperial Units</title>
2086 This switches between metric units (meters) and imperial
2087 units (feet and miles). This affects the display of values
2088 use during flight monitoring, configuration, data graphing
2089 and all of the voice announcements. It does not change the
2090 units used when exporting to CSV files, those are always
2091 produced in metric units.
2095 <title>Font Size</title>
2097 Selects the set of fonts used in the flight monitor
2098 window. Choose between the small, medium and large sets.
2102 <title>Serial Debug</title>
2104 This causes all communication with a connected device to be
2105 dumped to the console from which AltosUI was started. If
2106 you've started it from an icon or menu entry, the output
2107 will simply be discarded. This mode can be useful to debug
2108 various serial communication issues.
2112 <title>Manage Frequencies</title>
2114 This brings up a dialog where you can configure the set of
2115 frequencies shown in the various frequency menus. You can
2116 add as many as you like, or even reconfigure the default
2117 set. Changing this list does not affect the frequency
2118 settings of any devices, it only changes the set of
2119 frequencies shown in the menus.
2124 <title>Configure Groundstation</title>
2126 Select this button and then select a TeleDongle Device from the list provided.
2129 The first few lines of the dialog provide information about the
2130 connected device, including the product name,
2131 software version and hardware serial number. Below that are the
2132 individual configuration entries.
2135 Note that the TeleDongle itself doesn't save any configuration
2136 data, the settings here are recorded on the local machine in
2137 the Java preferences database. Moving the TeleDongle to
2138 another machine, or using a different user account on the same
2139 machine will cause settings made here to have no effect.
2142 At the bottom of the dialog, there are three buttons:
2149 This writes any changes to the
2150 local Java preferences file. If you don't
2151 press this button, any changes you make will be lost.
2159 This resets the dialog to the most recently saved values,
2160 erasing any changes you have made.
2168 This closes the dialog. Any unsaved changes will be
2175 The rest of the dialog contains the parameters to be configured.
2178 <title>Frequency</title>
2180 This configures the frequency to use for both telemetry and
2181 packet command mode. Set this before starting any operation
2182 involving packet command mode so that it will use the right
2183 frequency. Telemetry monitoring mode also provides a menu to
2184 change the frequency, and that menu also sets the same Java
2185 preference value used here.
2189 <title>Radio Calibration</title>
2191 The radios in every Altus Metrum device are calibrated at the
2192 factory to ensure that they transmit and receive on the
2193 specified frequency. To change a TeleDongle's calibration,
2194 you must reprogram the unit completely, so this entry simply
2195 shows the current value and doesn't allow any changes.
2200 <title>Flash Image</title>
2202 This reprograms Altus Metrum device with new
2203 firmware. TeleMetrum v1.x, TeleDongle, TeleMini and TeleBT are
2204 all reprogrammed by using another similar unit as a
2205 programming dongle (pair programming). TeleMega, TeleMetrum v2
2206 and EasyMini are all programmed directly over their USB ports
2207 (self programming). Please read the directions for flashing
2208 devices in the Updating Device Firmware chapter below.
2211 For “self programming”, connect USB to the device to be
2212 programmed and push the 'Flash Image' button. That will
2213 present a dialog box listing all of the connected
2214 devices. Carefully select the device to be programmed.
2217 For “pair programming”, once you have the programmer and
2218 target devices connected, push the 'Flash Image' button. That
2219 will present a dialog box listing all of the connected
2220 devices. Carefully select the programmer device, not the
2221 device to be programmed.
2224 Next, select the image to flash to the device. These are named
2225 with the product name and firmware version. The file selector
2226 will start in the directory containing the firmware included
2227 with the AltosUI package. Navigate to the directory containing
2228 the desired firmware if it isn't there.
2231 Next, a small dialog containing the device serial number and
2232 RF calibration values should appear. If these values are
2233 incorrect (possibly due to a corrupted image in the device),
2234 enter the correct values here.
2237 Finally, a dialog containing a progress bar will follow the
2238 programming process.
2241 When programming is complete, the target device will
2242 reboot. Note that if a pair programmed target device is
2243 connected via USB, you will have to unplug it and then plug it
2244 back in for the USB connection to reset so that you can
2245 communicate with the device again.
2249 <title>Fire Igniter</title>
2251 This activates the igniter circuits in TeleMetrum to help test
2252 recovery systems deployment. Because this command can operate
2253 over the Packet Command Link, you can prepare the rocket as
2254 for flight and then test the recovery system without needing
2255 to snake wires inside the air-frame.
2258 Selecting the 'Fire Igniter' button brings up the usual device
2259 selection dialog. Pick the desired TeleDongle or TeleMetrum
2260 device. This brings up another window which shows the current
2261 continuity test status for both apogee and main charges.
2264 Next, select the desired igniter to fire. This will enable the
2268 Select the 'Arm' button. This enables the 'Fire' button. The
2269 word 'Arm' is replaced by a countdown timer indicating that
2270 you have 10 seconds to press the 'Fire' button or the system
2271 will deactivate, at which point you start over again at
2272 selecting the desired igniter.
2276 <title>Scan Channels</title>
2278 This listens for telemetry packets on all of the configured
2279 frequencies, displaying information about each device it
2280 receives a packet from. You can select which of the three
2281 telemetry formats should be tried; by default, it only listens
2282 for the standard telemetry packets used in v1.0 and later
2287 <title>Load Maps</title>
2289 Before heading out to a new launch site, you can use this to
2290 load satellite images in case you don't have internet
2291 connectivity at the site. This loads a fairly large area
2292 around the launch site, which should cover any flight you're likely to make.
2295 There's a drop-down menu of launch sites we know about; if
2296 your favorites aren't there, please let us know the lat/lon
2297 and name of the site. The contents of this list are actually
2298 downloaded at run-time, so as new sites are sent in, they'll
2299 get automatically added to this list.
2302 If the launch site isn't in the list, you can manually enter the lat/lon values
2305 Clicking the 'Load Map' button will fetch images from Google
2306 Maps; note that Google limits how many images you can fetch at
2307 once, so if you load more than one launch site, you may get
2308 some gray areas in the map which indicate that Google is tired
2309 of sending data to you. Try again later.
2313 <title>Monitor Idle</title>
2315 This brings up a dialog similar to the Monitor Flight UI,
2316 except it works with the altimeter in “idle” mode by sending
2317 query commands to discover the current state rather than
2318 listening for telemetry packets. Because this uses command
2319 mode, it needs to have the TeleDongle and flight computer
2320 callsigns match exactly. If you can receive telemetry, but
2321 cannot manage to run Monitor Idle, then it's very likely that
2322 your callsigns are different in some way.
2327 <title>AltosDroid</title>
2329 AltosDroid provides the same flight monitoring capabilities as
2330 AltosUI, but runs on Android devices and is designed to connect
2331 to a TeleBT receiver over Bluetooth™. Altos Droid monitors
2332 telemetry data, logging it to internal storage in the Android
2333 device, and presents that data in a UI the same way the 'Monitor
2334 Flight' window does in AltosUI.
2337 This manual will explain how to configure AltosDroid, connect
2338 to TeleBT, operate the flight monitoring interface and describe
2339 what the displayed data means.
2342 <title>Installing AltosDroid</title>
2344 AltosDroid is included in the Google Play store. To install
2345 it on your Android device, open open the Google Play Store
2346 application and search for “altosdroid”. Make sure you don't
2347 have a space between “altos” and “droid” or you probably won't
2348 find what you want. That should bring you to the right page
2349 from which you can download and install the application.
2353 <title>Connecting to TeleBT</title>
2355 Press the Android 'Menu' button or soft-key to see the
2356 configuration options available. Select the 'Connect a device'
2357 option and then the 'Scan for devices' entry at the bottom to
2358 look for your TeleBT device. Select your device, and when it
2359 asks for the code, enter '1234'.
2362 Subsequent connections will not require you to enter that
2363 code, and your 'paired' device will appear in the list without
2368 <title>Configuring AltosDroid</title>
2370 The only configuration option available for AltosDroid is
2371 which frequency to listen on. Press the Android 'Menu' button
2372 or soft-key and pick the 'Select radio frequency' entry. That
2373 brings up a menu of pre-set radio frequencies; pick the one
2374 which matches your altimeter.
2378 <title>Altos Droid Flight Monitoring</title>
2380 Altos Droid is designed to mimic the AltosUI flight monitoring
2381 display, providing separate tabs for each stage of your rocket
2382 flight along with a tab containing a map of the local area
2383 with icons marking the current location of the altimeter and
2389 The 'Launch Pad' tab shows information used to decide when the
2390 rocket is ready for flight. The first elements include red/green
2391 indicators, if any of these is red, you'll want to evaluate
2392 whether the rocket is ready to launch:
2395 <term>Battery Voltage</term>
2398 This indicates whether the Li-Po battery
2399 powering the TeleMetrum has sufficient charge to last for
2400 the duration of the flight. A value of more than
2401 3.8V is required for a 'GO' status.
2406 <term>Apogee Igniter Voltage</term>
2409 This indicates whether the apogee
2410 igniter has continuity. If the igniter has a low
2411 resistance, then the voltage measured here will be close
2412 to the Li-Po battery voltage. A value greater than 3.2V is
2413 required for a 'GO' status.
2418 <term>Main Igniter Voltage</term>
2421 This indicates whether the main
2422 igniter has continuity. If the igniter has a low
2423 resistance, then the voltage measured here will be close
2424 to the Li-Po battery voltage. A value greater than 3.2V is
2425 required for a 'GO' status.
2430 <term>On-board Data Logging</term>
2433 This indicates whether there is
2434 space remaining on-board to store flight data for the
2435 upcoming flight. If you've downloaded data, but failed
2436 to erase flights, there may not be any space
2437 left. TeleMetrum can store multiple flights, depending
2438 on the configured maximum flight log size. TeleMini
2439 stores only a single flight, so it will need to be
2440 downloaded and erased after each flight to capture
2441 data. This only affects on-board flight logging; the
2442 altimeter will still transmit telemetry and fire
2443 ejection charges at the proper times.
2448 <term>GPS Locked</term>
2451 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
2452 currently able to compute position information. GPS requires
2453 at least 4 satellites to compute an accurate position.
2458 <term>GPS Ready</term>
2461 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
2462 10 consecutive positions without losing lock. This ensures
2463 that the GPS receiver has reliable reception from the
2471 The Launchpad tab also shows the computed launch pad position
2472 and altitude, averaging many reported positions to improve the
2473 accuracy of the fix.
2478 <title>Downloading Flight Logs</title>
2480 Altos Droid always saves every bit of telemetry data it
2481 receives. To download that to a computer for use with AltosUI,
2482 simply remove the SD card from your Android device, or connect
2483 your device to your computer's USB port and browse the files
2484 on that device. You will find '.telem' files in the TeleMetrum
2485 directory that will work with AltosUI directly.
2490 <title>Using Altus Metrum Products</title>
2492 <title>Being Legal</title>
2494 First off, in the US, you need an <ulink url="http://www.altusmetrum.org/Radio/">amateur radio license</ulink> or
2495 other authorization to legally operate the radio transmitters that are part
2500 <title>In the Rocket</title>
2502 In the rocket itself, you just need a <ulink url="http://www.altusmetrum.org/TeleMetrum/">TeleMetrum</ulink> or
2503 <ulink url="http://www.altusmetrum.org/TeleMini/">TeleMini</ulink> board and
2504 a single-cell, 3.7 volt nominal Li-Po rechargeable battery. An
2505 850mAh battery weighs less than a 9V alkaline battery, and will
2506 run a TeleMetrum for hours.
2507 A 110mAh battery weighs less than a triple A battery and will run a TeleMetrum for
2508 a few hours, or a TeleMini for much (much) longer.
2511 By default, we ship the altimeters with a simple wire antenna. If your
2512 electronics bay or the air-frame it resides within is made of carbon fiber,
2513 which is opaque to RF signals, you may choose to have an SMA connector
2514 installed so that you can run a coaxial cable to an antenna mounted
2515 elsewhere in the rocket.
2519 <title>On the Ground</title>
2521 To receive the data stream from the rocket, you need an antenna and short
2522 feed-line connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. If possible, use an SMA to BNC
2523 adapter instead of feedline between the antenna feedpoint and
2524 TeleDongle, as this will give you the best performance. The
2525 TeleDongle in turn plugs directly into the USB port on a notebook
2526 computer. Because TeleDongle looks like a simple serial port, your computer
2527 does not require special device drivers... just plug it in.
2530 The GUI tool, AltosUI, is written in Java and runs across
2531 Linux, Mac OS and Windows. There's also a suite of C tools
2532 for Linux which can perform most of the same tasks.
2535 After the flight, you can use the radio link to extract the more detailed data
2536 logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
2537 TeleMetrum board directly. Pulling out the data without having to open up
2538 the rocket is pretty cool! A USB cable is also how you charge the Li-Po
2539 battery, so you'll want one of those anyway... the same cable used by lots
2540 of digital cameras and other modern electronic stuff will work fine.
2543 If your TeleMetrum-equipped rocket lands out of sight, you may enjoy having a hand-held GPS
2544 receiver, so that you can put in a way-point for the last reported rocket
2545 position before touch-down. This makes looking for your rocket a lot like
2546 Geo-Caching... just go to the way-point and look around starting from there.
2549 You may also enjoy having a ham radio “HT” that covers the 70cm band... you
2550 can use that with your antenna to direction-find the rocket on the ground
2551 the same way you can use a Walston or Beeline tracker. This can be handy
2552 if the rocket is hiding in sage brush or a tree, or if the last GPS position
2553 doesn't get you close enough because the rocket dropped into a canyon, or
2554 the wind is blowing it across a dry lake bed, or something like that... Keith
2555 currently uses a Yaesu VX-7R, Bdale has a Baofung UV-5R
2556 which isn't as nice, but was a whole lot cheaper.
2559 So, to recap, on the ground the hardware you'll need includes:
2560 <orderedlist inheritnum='inherit' numeration='arabic'>
2563 an antenna and feed-line or adapter
2578 optionally, a hand-held GPS receiver
2583 optionally, an HT or receiver covering 435 MHz
2589 The best hand-held commercial directional antennas we've found for radio
2590 direction finding rockets are from
2591 <ulink url="http://www.arrowantennas.com/" >
2594 The 440-3 and 440-5 are both good choices for finding a
2595 TeleMetrum- or TeleMini- equipped rocket when used with a suitable
2596 70cm HT. TeleDongle and an SMA to BNC adapter fit perfectly
2597 between the driven element and reflector of Arrow antennas.
2601 <title>Data Analysis</title>
2603 Our software makes it easy to log the data from each flight, both the
2604 telemetry received during the flight itself, and the more
2605 complete data log recorded in the flash memory on the altimeter
2606 board. Once this data is on your computer, our post-flight tools make it
2607 easy to quickly get to the numbers everyone wants, like apogee altitude,
2608 max acceleration, and max velocity. You can also generate and view a
2609 standard set of plots showing the altitude, acceleration, and
2610 velocity of the rocket during flight. And you can even export a TeleMetrum data file
2611 usable with Google Maps and Google Earth for visualizing the flight path
2612 in two or three dimensions!
2615 Our ultimate goal is to emit a set of files for each flight that can be
2616 published as a web page per flight, or just viewed on your local disk with
2621 <title>Future Plans</title>
2623 In the future, we intend to offer “companion boards” for the rocket
2624 that will plug in to TeleMetrum to collect additional data, provide
2625 more pyro channels, and so forth.
2628 Also under design is a new flight computer with more sensors, more
2629 pyro channels, and a more powerful radio system designed for use
2630 in multi-stage, complex, and extreme altitude projects.
2633 We are also working on alternatives to TeleDongle. One is a
2634 a stand-alone, hand-held ground terminal that will allow monitoring
2635 the rocket's status, collecting data during flight, and logging data
2636 after flight without the need for a notebook computer on the
2637 flight line. Particularly since it is so difficult to read most
2638 notebook screens in direct sunlight, we think this will be a great
2639 thing to have. We are also working on a TeleDongle variant with
2640 Bluetooth that will work with Android phones and tablets.
2643 Because all of our work is open, both the hardware designs and the
2644 software, if you have some great idea for an addition to the current
2645 Altus Metrum family, feel free to dive in and help! Or let us know
2646 what you'd like to see that we aren't already working on, and maybe
2647 we'll get excited about it too...
2651 <ulink url="http://altusmetrum.org/">web site</ulink> for more news
2652 and information as our family of products evolves!
2657 <title>Altimeter Installation Recommendations</title>
2659 Building high-power rockets that fly safely is hard enough. Mix
2660 in some sophisticated electronics and a bunch of radio energy
2661 and oftentimes you find few perfect solutions. This chapter
2662 contains some suggestions about how to install Altus Metrum
2663 products into the rocket air-frame, including how to safely and
2664 reliably mix a variety of electronics into the same air-frame.
2667 <title>Mounting the Altimeter</title>
2669 The first consideration is to ensure that the altimeter is
2670 securely fastened to the air-frame. For TeleMetrum, we use
2671 nylon standoffs and nylon screws; they're good to at least 50G
2672 and cannot cause any electrical issues on the board. For
2673 TeleMini, we usually cut small pieces of 1/16 inch balsa to fit
2674 under the screw holes, and then take 2x56 nylon screws and
2675 screw them through the TeleMini mounting holes, through the
2676 balsa and into the underlying material.
2678 <orderedlist inheritnum='inherit' numeration='arabic'>
2681 Make sure TeleMetrum is aligned precisely along the axis of
2682 acceleration so that the accelerometer can accurately
2683 capture data during the flight.
2688 Watch for any metal touching components on the
2689 board. Shorting out connections on the bottom of the board
2690 can cause the altimeter to fail during flight.
2696 <title>Dealing with the Antenna</title>
2698 The antenna supplied is just a piece of solid, insulated,
2699 wire. If it gets damaged or broken, it can be easily
2700 replaced. It should be kept straight and not cut; bending or
2701 cutting it will change the resonant frequency and/or
2702 impedance, making it a less efficient radiator and thus
2703 reducing the range of the telemetry signal.
2706 Keeping metal away from the antenna will provide better range
2707 and a more even radiation pattern. In most rockets, it's not
2708 entirely possible to isolate the antenna from metal
2709 components; there are often bolts, all-thread and wires from other
2710 electronics to contend with. Just be aware that the more stuff
2711 like this around the antenna, the lower the range.
2714 Make sure the antenna is not inside a tube made or covered
2715 with conducting material. Carbon fiber is the most common
2716 culprit here -- CF is a good conductor and will effectively
2717 shield the antenna, dramatically reducing signal strength and
2718 range. Metallic flake paint is another effective shielding
2719 material which is to be avoided around any antennas.
2722 If the ebay is large enough, it can be convenient to simply
2723 mount the altimeter at one end and stretch the antenna out
2724 inside. Taping the antenna to the sled can keep it straight
2725 under acceleration. If there are metal rods, keep the
2726 antenna as far away as possible.
2729 For a shorter ebay, it's quite practical to have the antenna
2730 run through a bulkhead and into an adjacent bay. Drill a small
2731 hole in the bulkhead, pass the antenna wire through it and
2732 then seal it up with glue or clay. We've also used acrylic
2733 tubing to create a cavity for the antenna wire. This works a
2734 bit better in that the antenna is known to stay straight and
2735 not get folded by recovery components in the bay. Angle the
2736 tubing towards the side wall of the rocket and it ends up
2737 consuming very little space.
2740 If you need to place the antenna at a distance from the
2741 altimeter, you can replace the antenna with an edge-mounted
2742 SMA connector, and then run 50Ω coax from the board to the
2743 antenna. Building a remote antenna is beyond the scope of this
2748 <title>Preserving GPS Reception</title>
2750 The GPS antenna and receiver in TeleMetrum are highly
2751 sensitive and normally have no trouble tracking enough
2752 satellites to provide accurate position information for
2753 recovering the rocket. However, there are many ways to
2754 attenuate the GPS signal.
2755 <orderedlist inheritnum='inherit' numeration='arabic'>
2758 Conductive tubing or coatings. Carbon fiber and metal
2759 tubing, or metallic paint will all dramatically attenuate the
2760 GPS signal. We've never heard of anyone successfully
2761 receiving GPS from inside these materials.
2766 Metal components near the GPS patch antenna. These will
2767 de-tune the patch antenna, changing the resonant frequency
2768 away from the L1 carrier and reduce the effectiveness of the
2769 antenna. You can place as much stuff as you like beneath the
2770 antenna as that's covered with a ground plane. But, keep
2771 wires and metal out from above the patch antenna.
2778 <title>Radio Frequency Interference</title>
2780 Any altimeter will generate RFI; the digital circuits use
2781 high-frequency clocks that spray radio interference across a
2782 wide band. Altus Metrum altimeters generate intentional radio
2783 signals as well, increasing the amount of RF energy around the board.
2786 Rocketry altimeters also use precise sensors measuring air
2787 pressure and acceleration. Tiny changes in voltage can cause
2788 these sensor readings to vary by a huge amount. When the
2789 sensors start mis-reporting data, the altimeter can either
2790 fire the igniters at the wrong time, or not fire them at all.
2793 Voltages are induced when radio frequency energy is
2794 transmitted from one circuit to another. Here are things that
2795 influence the induced voltage and current:
2800 Keep wires from different circuits apart. Moving circuits
2801 further apart will reduce RFI.
2806 Avoid parallel wires from different circuits. The longer two
2807 wires run parallel to one another, the larger the amount of
2808 transferred energy. Cross wires at right angles to reduce
2814 Twist wires from the same circuits. Two wires the same
2815 distance from the transmitter will get the same amount of
2816 induced energy which will then cancel out. Any time you have
2817 a wire pair running together, twist the pair together to
2818 even out distances and reduce RFI. For altimeters, this
2819 includes battery leads, switch hookups and igniter
2825 Avoid resonant lengths. Know what frequencies are present
2826 in the environment and avoid having wire lengths near a
2827 natural resonant length. Altusmetrum products transmit on the
2828 70cm amateur band, so you should avoid lengths that are a
2829 simple ratio of that length; essentially any multiple of ¼
2830 of the wavelength (17.5cm).
2836 <title>The Barometric Sensor</title>
2838 Altusmetrum altimeters measure altitude with a barometric
2839 sensor, essentially measuring the amount of air above the
2840 rocket to figure out how high it is. A large number of
2841 measurements are taken as the altimeter initializes itself to
2842 figure out the pad altitude. Subsequent measurements are then
2843 used to compute the height above the pad.
2846 To accurately measure atmospheric pressure, the ebay
2847 containing the altimeter must be vented outside the
2848 air-frame. The vent must be placed in a region of linear
2849 airflow, have smooth edges, and away from areas of increasing or
2850 decreasing pressure.
2853 The barometric sensor in the altimeter is quite sensitive to
2854 chemical damage from the products of APCP or BP combustion, so
2855 make sure the ebay is carefully sealed from any compartment
2856 which contains ejection charges or motors.
2860 <title>Ground Testing</title>
2862 The most important aspect of any installation is careful
2863 ground testing. Bringing an air-frame up to the LCO table which
2864 hasn't been ground tested can lead to delays or ejection
2865 charges firing on the pad, or, even worse, a recovery system
2869 Do a 'full systems' test that includes wiring up all igniters
2870 without any BP and turning on all of the electronics in flight
2871 mode. This will catch any mistakes in wiring and any residual
2872 RFI issues that might accidentally fire igniters at the wrong
2873 time. Let the air-frame sit for several minutes, checking for
2874 adequate telemetry signal strength and GPS lock. If any igniters
2875 fire unexpectedly, find and resolve the issue before loading any
2879 Ground test the ejection charges. Prepare the rocket for
2880 flight, loading ejection charges and igniters. Completely
2881 assemble the air-frame and then use the 'Fire Igniters'
2882 interface through a TeleDongle to command each charge to
2883 fire. Make sure the charge is sufficient to robustly separate
2884 the air-frame and deploy the recovery system.
2889 <title>Updating Device Firmware</title>
2891 TeleMega, TeleMetrum v2 and EasyMini are all programmed directly
2892 over their USB connectors (self programming). TeleMetrum v1, TeleMini and
2893 TeleDongle are all programmed by using another device as a
2894 programmer (pair programming). It's important to recognize which
2895 kind of devices you have before trying to reprogram them.
2898 You may wish to begin by ensuring you have current firmware images.
2899 These are distributed as part of the AltOS software bundle that
2900 also includes the AltosUI ground station program. Newer ground
2901 station versions typically work fine with older firmware versions,
2902 so you don't need to update your devices just to try out new
2903 software features. You can always download the most recent
2904 version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
2907 We recommend updating the altimeter first, before updating TeleDongle.
2910 Self-programmable devices (TeleMega, TeleMetrum v2 and EasyMini)
2911 are reprogrammed by connecting them to your computer over USB
2915 Updating TeleMega, TeleMetrum v2 or EasyMini Firmware
2917 <orderedlist inheritnum='inherit' numeration='arabic'>
2920 Attach a battery and power switch to the target
2921 device. Power up the device.
2926 Using a Micro USB cable, connect the target device to your
2927 computer's USB socket.
2932 Run AltosUI, and select 'Flash Image' from the File menu.
2937 Select the target device in the Device Selection dialog.
2942 Select the image you want to flash to the device, which
2943 should have a name in the form
2944 <product>-v<product-version>-<software-version>.ihx, such
2945 as TeleMega-v1.0-1.3.0.ihx.
2950 Make sure the configuration parameters are reasonable
2951 looking. If the serial number and/or RF configuration
2952 values aren't right, you'll need to change them.
2957 Hit the 'OK' button and the software should proceed to flash
2958 the device with new firmware, showing a progress bar.
2963 Verify that the device is working by using the 'Configure
2964 Altimeter' item to check over the configuration.
2969 <title>Recovering From Self-Flashing Failure</title>
2971 If the firmware loading fails, it can leave the device
2972 unable to boot. Not to worry, you can force the device to
2973 start the boot loader instead, which will let you try to
2974 flash the device again.
2977 On each device, connecting two pins from one of the exposed
2978 connectors will force the boot loader to start, even if the
2979 regular operating system has been corrupted in some way.
2983 <term>TeleMega</term>
2986 Connect pin 6 and pin 1 of the companion connector. Pin 1
2987 can be identified by the square pad around it, and then
2988 the pins could sequentially across the board. Be very
2989 careful to <emphasis>not</emphasis> short pin 8 to
2990 anything as that is connected directly to the battery. Pin
2991 7 carries 3.3V and the board will crash if that is
2992 connected to pin 1, but shouldn't damage the board.
2997 <term>TeleMetrum v2</term>
3000 Connect pin 6 and pin 1 of the companion connector. Pin 1
3001 can be identified by the square pad around it, and then
3002 the pins could sequentially across the board. Be very
3003 careful to <emphasis>not</emphasis> short pin 8 to
3004 anything as that is connected directly to the battery. Pin
3005 7 carries 3.3V and the board will crash if that is
3006 connected to pin 1, but shouldn't damage the board.
3011 <term>EasyMini</term>
3014 Connect pin 6 and pin 1 of the debug connector, which is
3015 the six holes next to the beeper. Pin 1 can be identified
3016 by the square pad around it, and then the pins could
3017 sequentially across the board, making Pin 6 the one on the
3018 other end of the row.
3026 <title>Pair Programming</title>
3028 The big concept to understand is that you have to use a
3029 TeleMega, TeleMetrum or TeleDongle as a programmer to update a
3030 pair programmed device. Due to limited memory resources in the
3031 cc1111, we don't support programming directly over USB for these
3036 <title>Updating TeleMetrum v1.x Firmware</title>
3037 <orderedlist inheritnum='inherit' numeration='arabic'>
3040 Find the 'programming cable' that you got as part of the starter
3041 kit, that has a red 8-pin MicroMaTch connector on one end and a
3042 red 4-pin MicroMaTch connector on the other end.
3047 Take the 2 screws out of the TeleDongle case to get access
3048 to the circuit board.
3053 Plug the 8-pin end of the programming cable to the
3054 matching connector on the TeleDongle, and the 4-pin end to the
3055 matching connector on the TeleMetrum.
3056 Note that each MicroMaTch connector has an alignment pin that
3057 goes through a hole in the PC board when you have the cable
3063 Attach a battery to the TeleMetrum board.
3068 Plug the TeleDongle into your computer's USB port, and power
3074 Run AltosUI, and select 'Flash Image' from the File menu.
3079 Pick the TeleDongle device from the list, identifying it as the
3085 Select the image you want put on the TeleMetrum, which should have a
3086 name in the form telemetrum-v1.2-1.0.0.ihx. It should be visible
3087 in the default directory, if not you may have to poke around
3088 your system to find it.
3093 Make sure the configuration parameters are reasonable
3094 looking. If the serial number and/or RF configuration
3095 values aren't right, you'll need to change them.
3100 Hit the 'OK' button and the software should proceed to flash
3101 the TeleMetrum with new firmware, showing a progress bar.
3106 Confirm that the TeleMetrum board seems to have updated OK, which you
3107 can do by plugging in to it over USB and using a terminal program
3108 to connect to the board and issue the 'v' command to check
3114 If something goes wrong, give it another try.
3120 <title>Updating TeleMini Firmware</title>
3121 <orderedlist inheritnum='inherit' numeration='arabic'>
3124 You'll need a special 'programming cable' to reprogram the
3125 TeleMini. It's available on the Altus Metrum web store, or
3126 you can make your own using an 8-pin MicroMaTch connector on
3127 one end and a set of four pins on the other.
3132 Take the 2 screws out of the TeleDongle case to get access
3133 to the circuit board.
3138 Plug the 8-pin end of the programming cable to the matching
3139 connector on the TeleDongle, and the 4-pins into the holes
3140 in the TeleMini circuit board. Note that the MicroMaTch
3141 connector has an alignment pin that goes through a hole in
3142 the PC board when you have the cable oriented correctly, and
3143 that pin 1 on the TeleMini board is marked with a square pad
3144 while the other pins have round pads.
3149 Attach a battery to the TeleMini board.
3154 Plug the TeleDongle into your computer's USB port, and power
3160 Run AltosUI, and select 'Flash Image' from the File menu.
3165 Pick the TeleDongle device from the list, identifying it as the
3171 Select the image you want put on the TeleMini, which should have a
3172 name in the form telemini-v1.0-1.0.0.ihx. It should be visible
3173 in the default directory, if not you may have to poke around
3174 your system to find it.
3179 Make sure the configuration parameters are reasonable
3180 looking. If the serial number and/or RF configuration
3181 values aren't right, you'll need to change them.
3186 Hit the 'OK' button and the software should proceed to flash
3187 the TeleMini with new firmware, showing a progress bar.
3192 Confirm that the TeleMini board seems to have updated OK, which you
3193 can do by configuring it over the radio link through the TeleDongle, or
3194 letting it come up in “flight” mode and listening for telemetry.
3199 If something goes wrong, give it another try.
3205 <title>Updating TeleDongle Firmware</title>
3207 Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
3208 firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
3210 <orderedlist inheritnum='inherit' numeration='arabic'>
3213 Find the 'programming cable' that you got as part of the starter
3214 kit, that has a red 8-pin MicroMaTch connector on one end and a
3215 red 4-pin MicroMaTch connector on the other end.
3220 Find the USB cable that you got as part of the starter kit, and
3221 plug the “mini” end in to the mating connector on TeleMetrum or TeleDongle.
3226 Take the 2 screws out of the TeleDongle case to get access
3227 to the circuit board.
3232 Plug the 8-pin end of the programming cable to the
3233 matching connector on the programmer, and the 4-pin end to the
3234 matching connector on the TeleDongle.
3235 Note that each MicroMaTch connector has an alignment pin that
3236 goes through a hole in the PC board when you have the cable
3242 Attach a battery to the TeleMetrum board if you're using one.
3247 Plug both the programmer and the TeleDongle into your computer's USB
3248 ports, and power up the programmer.
3253 Run AltosUI, and select 'Flash Image' from the File menu.
3258 Pick the programmer device from the list, identifying it as the
3264 Select the image you want put on the TeleDongle, which should have a
3265 name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
3266 in the default directory, if not you may have to poke around
3267 your system to find it.
3272 Make sure the configuration parameters are reasonable
3273 looking. If the serial number and/or RF configuration
3274 values aren't right, you'll need to change them. The TeleDongle
3275 serial number is on the “bottom” of the circuit board, and can
3276 usually be read through the translucent blue plastic case without
3277 needing to remove the board from the case.
3282 Hit the 'OK' button and the software should proceed to flash
3283 the TeleDongle with new firmware, showing a progress bar.
3288 Confirm that the TeleDongle board seems to have updated OK, which you
3289 can do by plugging in to it over USB and using a terminal program
3290 to connect to the board and issue the 'v' command to check
3291 the version, etc. Once you're happy, remove the programming cable
3292 and put the cover back on the TeleDongle.
3297 If something goes wrong, give it another try.
3302 Be careful removing the programming cable from the locking 8-pin
3303 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
3304 screwdriver or knife blade to gently pry the locking ears out
3305 slightly to extract the connector. We used a locking connector on
3306 TeleMetrum to help ensure that the cabling to companion boards
3307 used in a rocket don't ever come loose accidentally in flight.
3312 <title>Hardware Specifications</title>
3315 TeleMega Specifications
3320 Recording altimeter for model rocketry.
3325 Supports dual deployment and four auxiliary pyro channels
3326 (a total of 6 events).
3331 70cm 40mW ham-band transceiver for telemetry down-link.
3336 Barometric pressure sensor good to 100k feet MSL.
3341 1-axis high-g accelerometer for motor characterization, capable of
3347 9-axis IMU including integrated 3-axis accelerometer,
3348 3-axis gyroscope and 3-axis magnetometer.
3353 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
3358 On-board 8 Megabyte non-volatile memory for flight data storage.
3363 USB interface for battery charging, configuration, and data recovery.
3368 Fully integrated support for Li-Po rechargeable batteries.
3373 Uses Li-Po to fire e-matches, can be modified to support
3374 optional separate pyro battery if needed.
3379 3.25 x 1.25 inch board designed to fit inside 38mm air-frame coupler tube.
3386 TeleMetrum v2 Specifications
3391 Recording altimeter for model rocketry.
3396 Supports dual deployment (can fire 2 ejection charges).
3401 70cm, 40mW ham-band transceiver for telemetry down-link.
3406 Barometric pressure sensor good to 100k feet MSL.
3411 1-axis high-g accelerometer for motor characterization, capable of
3417 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
3422 On-board 8 Megabyte non-volatile memory for flight data storage.
3427 USB interface for battery charging, configuration, and data recovery.
3432 Fully integrated support for Li-Po rechargeable batteries.
3437 Uses Li-Po to fire e-matches, can be modified to support
3438 optional separate pyro battery if needed.
3443 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
3449 <title>TeleMetrum v1 Specifications</title>
3453 Recording altimeter for model rocketry.
3458 Supports dual deployment (can fire 2 ejection charges).
3463 70cm, 10mW ham-band transceiver for telemetry down-link.
3468 Barometric pressure sensor good to 45k feet MSL.
3473 1-axis high-g accelerometer for motor characterization, capable of
3474 +/- 50g using default part.
3479 On-board, integrated GPS receiver with 5Hz update rate capability.
3484 On-board 1 megabyte non-volatile memory for flight data storage.
3489 USB interface for battery charging, configuration, and data recovery.
3494 Fully integrated support for Li-Po rechargeable batteries.
3499 Uses Li-Po to fire e-matches, can be modified to support
3500 optional separate pyro battery if needed.
3505 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
3512 TeleMini v2.0 Specifications
3517 Recording altimeter for model rocketry.
3522 Supports dual deployment (can fire 2 ejection charges).
3527 70cm, 10mW ham-band transceiver for telemetry down-link.
3532 Barometric pressure sensor good to 100k feet MSL.
3537 On-board 1 megabyte non-volatile memory for flight data storage.
3542 USB interface for configuration, and data recovery.
3547 Support for Li-Po rechargeable batteries (using an
3548 external charger), or any 3.7-15V external battery.
3553 Uses Li-Po to fire e-matches, can be modified to support
3554 optional separate pyro battery if needed.
3559 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
3566 TeleMini v1.0 Specifications
3571 Recording altimeter for model rocketry.
3576 Supports dual deployment (can fire 2 ejection charges).
3581 70cm, 10mW ham-band transceiver for telemetry down-link.
3586 Barometric pressure sensor good to 45k feet MSL.
3591 On-board 5 kilobyte non-volatile memory for flight data storage.
3596 RF interface for configuration, and data recovery.
3601 Support for Li-Po rechargeable batteries, using an external charger.
3606 Uses Li-Po to fire e-matches, can be modified to support
3607 optional separate pyro battery if needed.
3612 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube.
3619 EasyMini Specifications
3624 Recording altimeter for model rocketry.
3629 Supports dual deployment (can fire 2 ejection charges).
3634 Barometric pressure sensor good to 100k feet MSL.
3639 On-board 1 megabyte non-volatile memory for flight data storage.
3644 USB interface for configuration, and data recovery.
3649 Support for Li-Po rechargeable batteries (using an
3650 external charger), or any 3.7-15V external battery.
3655 Uses Li-Po to fire e-matches, can be modified to support
3656 optional separate pyro battery if needed.
3661 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
3670 TeleMetrum seems to shut off when disconnected from the
3671 computer. Make sure the battery is adequately charged. Remember the
3672 unit will pull more power than the USB port can deliver before the
3673 GPS enters “locked” mode. The battery charges best when TeleMetrum
3677 It's impossible to stop the TeleDongle when it's in “p” mode, I have
3678 to unplug the USB cable? Make sure you have tried to “escape out” of
3679 this mode. If this doesn't work the reboot procedure for the
3680 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
3681 outgoing buffer IF your “escape out” ('~~') does not work.
3682 At this point using either 'ao-view' (or possibly
3683 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
3687 The amber LED (on the TeleMetrum) lights up when both
3688 battery and USB are connected. Does this mean it's charging?
3689 Yes, the yellow LED indicates the charging at the 'regular' rate.
3690 If the led is out but the unit is still plugged into a USB port,
3691 then the battery is being charged at a 'trickle' rate.
3694 There are no “dit-dah-dah-dit” sound or lights like the manual mentions?
3695 That's the “pad” mode. Weak batteries might be the problem.
3696 It is also possible that the TeleMetrum is horizontal and the output
3697 is instead a “dit-dit” meaning 'idle'. For TeleMini, it's possible that
3698 it received a command packet which would have left it in “pad” mode.
3701 How do I save flight data?
3702 Live telemetry is written to file(s) whenever AltosUI is connected
3703 to the TeleDongle. The file area defaults to ~/TeleMetrum
3704 but is easily changed using the menus in AltosUI. The files that
3705 are written end in '.telem'. The after-flight
3706 data-dumped files will end in .eeprom and represent continuous data
3707 unlike the .telem files that are subject to losses
3708 along the RF data path.
3709 See the above instructions on what and how to save the eeprom stored
3710 data after physically retrieving your altimeter. Make sure to save
3711 the on-board data after each flight; while the TeleMetrum can store
3712 multiple flights, you never know when you'll lose the altimeter...
3716 <title>Notes for Older Software</title>
3719 Before AltosUI was written, using Altus Metrum devices required
3720 some finesse with the Linux command line. There was a limited
3721 GUI tool, ao-view, which provided functionality similar to the
3722 Monitor Flight window in AltosUI, but everything else was a
3723 fairly 80's experience. This appendix includes documentation for
3724 using that software.
3728 Both TeleMetrum and TeleDongle can be directly communicated
3729 with using USB ports. The first thing you should try after getting
3730 both units plugged into to your computer's USB port(s) is to run
3731 'ao-list' from a terminal-window to see what port-device-name each
3732 device has been assigned by the operating system.
3733 You will need this information to access the devices via their
3734 respective on-board firmware and data using other command line
3735 programs in the AltOS software suite.
3738 TeleMini can be communicated with through a TeleDongle device
3739 over the radio link. When first booted, TeleMini listens for a
3740 TeleDongle device and if it receives a packet, it goes into
3741 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be
3742 launched. The easiest way to get it talking is to start the
3743 communication link on the TeleDongle and the power up the
3747 To access the device's firmware for configuration you need a terminal
3748 program such as you would use to talk to a modem. The software
3749 authors prefer using the program 'cu' which comes from the UUCP package
3750 on most Unix-like systems such as Linux. An example command line for
3751 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
3752 indicated from running the
3753 ao-list program. Another reasonable terminal program for Linux is
3754 'cutecom'. The default 'escape'
3755 character used by CU (i.e. the character you use to
3756 issue commands to cu itself instead of sending the command as input
3757 to the connected device) is a '~'. You will need this for use in
3758 only two different ways during normal operations. First is to exit
3759 the program by sending a '~.' which is called a 'escape-disconnect'
3760 and allows you to close-out from 'cu'. The
3761 second use will be outlined later.
3764 All of the Altus Metrum devices share the concept of a two level
3765 command set in their firmware.
3766 The first layer has several single letter commands. Once
3767 you are using 'cu' (or 'cutecom') sending (typing) a '?'
3768 returns a full list of these
3769 commands. The second level are configuration sub-commands accessed
3770 using the 'c' command, for
3771 instance typing 'c?' will give you this second level of commands
3772 (all of which require the
3773 letter 'c' to access). Please note that most configuration options
3774 are stored only in Flash memory; TeleDongle doesn't provide any storage
3775 for these options and so they'll all be lost when you unplug it.
3778 Try setting these configuration ('c' or second level menu) values. A good
3779 place to start is by setting your call sign. By default, the boards
3780 use 'N0CALL' which is cute, but not exactly legal!
3781 Spend a few minutes getting comfortable with the units, their
3782 firmware, and 'cu' (or possibly 'cutecom').
3783 For instance, try to send
3784 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
3785 Verify you can connect and disconnect from the units while in your
3786 terminal program by sending the escape-disconnect mentioned above.
3789 To set the radio frequency, use the 'c R' command to specify the
3790 radio transceiver configuration parameter. This parameter is computed
3791 using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
3792 the standard calibration reference frequency, 'S', (normally 434.550MHz):
3796 Round the result to the nearest integer value.
3797 As with all 'c' sub-commands, follow this with a 'c w' to write the
3798 change to the parameter block in the on-board flash on
3799 your altimeter board if you want the change to stay in place across reboots.
3802 To set the apogee delay, use the 'c d' command.
3803 As with all 'c' sub-commands, follow this with a 'c w' to write the
3804 change to the parameter block in the on-board DataFlash chip.
3807 To set the main deployment altitude, use the 'c m' command.
3808 As with all 'c' sub-commands, follow this with a 'c w' to write the
3809 change to the parameter block in the on-board DataFlash chip.
3812 To calibrate the radio frequency, connect the UHF antenna port to a
3813 frequency counter, set the board to 434.550MHz, and use the 'C'
3814 command to generate a CW carrier. Wait for the transmitter temperature
3815 to stabilize and the frequency to settle down.
3816 Then, divide 434.550 MHz by the
3817 measured frequency and multiply by the current radio cal value show
3818 in the 'c s' command. For an unprogrammed board, the default value
3819 is 1186611. Take the resulting integer and program it using the 'c f'
3820 command. Testing with the 'C' command again should show a carrier
3821 within a few tens of Hertz of the intended frequency.
3822 As with all 'c' sub-commands, follow this with a 'c w' to write the
3823 change to the parameter block in the on-board DataFlash chip.
3826 Note that the 'reboot' command, which is very useful on the altimeters,
3827 will likely just cause problems with the dongle. The *correct* way
3828 to reset the dongle is just to unplug and re-plug it.
3831 A fun thing to do at the launch site and something you can do while
3832 learning how to use these units is to play with the radio link access
3833 between an altimeter and the TeleDongle. Be aware that you *must* create
3834 some physical separation between the devices, otherwise the link will
3835 not function due to signal overload in the receivers in each device.
3838 Now might be a good time to take a break and read the rest of this
3839 manual, particularly about the two “modes” that the altimeters
3840 can be placed in. TeleMetrum uses the position of the device when booting
3841 up will determine whether the unit is in “pad” or “idle” mode. TeleMini
3842 enters “idle” mode when it receives a command packet within the first 5 seconds
3843 of being powered up, otherwise it enters “pad” mode.
3846 You can access an altimeter in idle mode from the TeleDongle's USB
3847 connection using the radio link
3848 by issuing a 'p' command to the TeleDongle. Practice connecting and
3849 disconnecting ('~~' while using 'cu') from the altimeter. If
3850 you cannot escape out of the “p” command, (by using a '~~' when in
3851 CU) then it is likely that your kernel has issues. Try a newer version.
3854 Using this radio link allows you to configure the altimeter, test
3855 fire e-matches and igniters from the flight line, check pyro-match
3856 continuity and so forth. You can leave the unit turned on while it
3857 is in 'idle mode' and then place the
3858 rocket vertically on the launch pad, walk away and then issue a
3859 reboot command. The altimeter will reboot and start sending data
3860 having changed to the “pad” mode. If the TeleDongle is not receiving
3861 this data, you can disconnect 'cu' from the TeleDongle using the
3862 procedures mentioned above and THEN connect to the TeleDongle from
3863 inside 'ao-view'. If this doesn't work, disconnect from the
3864 TeleDongle, unplug it, and try again after plugging it back in.
3867 In order to reduce the chance of accidental firing of pyrotechnic
3868 charges, the command to fire a charge is intentionally somewhat
3869 difficult to type, and the built-in help is slightly cryptic to
3870 prevent accidental echoing of characters from the help text back at
3871 the board from firing a charge. The command to fire the apogee
3872 drogue charge is 'i DoIt drogue' and the command to fire the main
3873 charge is 'i DoIt main'.
3876 On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
3877 and 'ao-view' will both auditorily announce and visually indicate
3879 Now you can launch knowing that you have a good data path and
3880 good satellite lock for flight data and recovery. Remember
3881 you MUST tell ao-view to connect to the TeleDongle explicitly in
3882 order for ao-view to be able to receive data.
3885 The altimeters provide RDF (radio direction finding) tones on
3886 the pad, during descent and after landing. These can be used to
3887 locate the rocket using a directional antenna; the signal
3888 strength providing an indication of the direction from receiver to rocket.
3891 TeleMetrum also provides GPS tracking data, which can further simplify
3892 locating the rocket once it has landed. (The last good GPS data
3893 received before touch-down will be on the data screen of 'ao-view'.)
3896 Once you have recovered the rocket you can download the eeprom
3897 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
3898 either a USB cable or over the radio link using TeleDongle.
3899 And by following the man page for 'ao-postflight' you can create
3900 various data output reports, graphs, and even KML data to see the
3901 flight trajectory in Google-earth. (Moving the viewing angle making
3902 sure to connect the yellow lines while in Google-earth is the proper
3906 As for ao-view.... some things are in the menu but don't do anything
3907 very useful. The developers have stopped working on ao-view to focus
3908 on a new, cross-platform ground station program. So ao-view may or
3909 may not be updated in the future. Mostly you just use
3910 the Log and Device menus. It has a wonderful display of the incoming
3911 flight data and I am sure you will enjoy what it has to say to you
3912 once you enable the voice output!
3916 <title>Drill Templates</title>
3918 These images, when printed, provide precise templates for the
3919 mounting holes in Altus Metrum flight computers
3922 <title>TeleMega template</title>
3924 TeleMega has overall dimensions of 1.250 x 3.250 inches, and
3925 the mounting holes are sized for use with 4-40 or M3 screws.
3927 <mediaobject id="TeleMegaTemplate">
3929 <imagedata format="SVG" fileref="telemega-outline.svg"/>
3934 <title>TeleMetrum template</title>
3936 TeleMetrum has overall dimensions of 1.000 x 2.750 inches, and the
3937 mounting holes are sized for use with 4-40 or M3 screws.
3939 <mediaobject id="TeleMetrumTemplate">
3941 <imagedata format="SVG" fileref="telemetrum.svg"/>
3946 <title>TeleMini v2/EasyMini template</title>
3948 TeleMini v2 and EasyMini have overall dimensions of 0.800 x 1.500 inches, and the
3949 mounting holes are sized for use with 4-40 or M3 screws.
3951 <mediaobject id="MiniTemplate">
3953 <imagedata format="SVG" fileref="easymini-outline.svg"/>
3958 <title>TeleMini v1 template</title>
3960 TeleMini has overall dimensions of 0.500 x 1.500 inches, and the
3961 mounting holes are sized for use with 2-56 or M2 screws.
3963 <mediaobject id="TeleMiniTemplate">
3965 <imagedata format="SVG" fileref="telemini.svg"/>
3971 <title>Calibration</title>
3973 There are only two calibrations required for TeleMetrum and
3974 TeleMega, and only one for TeleDongle, TeleMini and EasyMini.
3975 All boards are shipped from the factory pre-calibrated, but
3976 the procedures are documented here in case they are ever
3977 needed. Re-calibration is not supported by AltosUI, you must
3978 connect to the board with a serial terminal program and
3979 interact directly with the on-board command interpreter to
3983 <title>Radio Frequency</title>
3985 The radio frequency is synthesized from a clock based on the
3986 crystal on the board. The actual frequency of this oscillator
3987 must be measured to generate a calibration constant. While our
3989 bandwidth is wide enough to allow boards to communicate even when
3990 their oscillators are not on exactly the same frequency, performance
3991 is best when they are closely matched.
3992 Radio frequency calibration requires a calibrated frequency counter.
3993 Fortunately, once set, the variation in frequency due to aging and
3994 temperature changes is small enough that re-calibration by customers
3995 should generally not be required.
3998 To calibrate the radio frequency, connect the UHF antenna
3999 port to a frequency counter, set the board to 434.550MHz,
4000 and use the 'C' command in the on-board command interpreter
4001 to generate a CW carrier. For USB-enabled boards, this is
4002 best done over USB. For TeleMini v1, note that the only way
4003 to escape the 'C' command is via power cycle since the board
4004 will no longer be listening for commands once it starts
4005 generating a CW carrier.
4008 Wait for the transmitter temperature to stabilize and the frequency
4009 to settle down. Then, divide 434.550 MHz by the
4010 measured frequency and multiply by the current radio cal value show
4011 in the 'c s' command. For an unprogrammed board, the default value
4012 is 1186611. Take the resulting integer and program it using the 'c f'
4013 command. Testing with the 'C' command again should show a carrier
4014 within a few tens of Hertz of the intended frequency.
4015 As with all 'c' sub-commands, follow this with a 'c w' to write the
4016 change to the parameter block in the on-board storage chip.
4019 Note that any time you re-do the radio frequency calibration, the
4020 radio frequency is reset to the default 434.550 Mhz. If you want
4021 to use another frequency, you will have to set that again after
4022 calibration is completed.
4026 <title>TeleMetrum and TeleMega Accelerometers</title>
4028 While barometric sensors are factory-calibrated,
4029 accelerometers are not, and so each must be calibrated once
4030 installed in a flight computer. Explicitly calibrating the
4031 accelerometers also allows us to load any compatible device.
4032 We perform a two-point calibration using gravity.
4035 To calibrate the acceleration sensor, use the 'c a 0' command. You
4036 will be prompted to orient the board vertically with the UHF antenna
4037 up and press a key, then to orient the board vertically with the
4038 UHF antenna down and press a key. Note that the accuracy of this
4039 calibration depends primarily on how perfectly vertical and still
4040 the board is held during the cal process. As with all 'c'
4041 sub-commands, follow this with a 'c w' to write the
4042 change to the parameter block in the on-board DataFlash chip.
4045 The +1g and -1g calibration points are included in each telemetry
4046 frame and are part of the header stored in onboard flash to be
4047 downloaded after flight. We always store and return raw ADC
4048 samples for each sensor... so nothing is permanently “lost” or
4049 “damaged” if the calibration is poor.
4052 In the unlikely event an accel cal goes badly, it is possible
4053 that TeleMetrum or TeleMega may always come up in 'pad mode'
4054 and as such not be listening to either the USB or radio link.
4055 If that happens, there is a special hook in the firmware to
4056 force the board back in to 'idle mode' so you can re-do the
4057 cal. To use this hook, you just need to ground the SPI clock
4058 pin at power-on. This pin is available as pin 2 on the 8-pin
4059 companion connector, and pin 1 is ground. So either
4060 carefully install a fine-gauge wire jumper between the two
4061 pins closest to the index hole end of the 8-pin connector, or
4062 plug in the programming cable to the 8-pin connector and use
4063 a small screwdriver or similar to short the two pins closest
4064 to the index post on the 4-pin end of the programming cable,
4065 and power up the board. It should come up in 'idle mode'
4066 (two beeps), allowing a re-cal.
4071 <title>Release Notes</title>
4073 <title>Version 1.3</title>
4075 xmlns:xi="http://www.w3.org/2001/XInclude"
4076 href="release-notes-1.3.xsl"
4077 xpointer="xpointer(/article/*)"/>
4080 <title>Version 1.2.1</title>
4082 xmlns:xi="http://www.w3.org/2001/XInclude"
4083 href="release-notes-1.2.1.xsl"
4084 xpointer="xpointer(/article/*)"/>
4087 <title>Version 1.2</title>
4089 xmlns:xi="http://www.w3.org/2001/XInclude"
4090 href="release-notes-1.2.xsl"
4091 xpointer="xpointer(/article/*)"/>
4094 <title>Version 1.1.1</title>
4096 xmlns:xi="http://www.w3.org/2001/XInclude"
4097 href="release-notes-1.1.1.xsl"
4098 xpointer="xpointer(/article/*)"/>
4101 <title>Version 1.1</title>
4103 xmlns:xi="http://www.w3.org/2001/XInclude"
4104 href="release-notes-1.1.xsl"
4105 xpointer="xpointer(/article/*)"/>
4108 <title>Version 1.0.1</title>
4110 xmlns:xi="http://www.w3.org/2001/XInclude"
4111 href="release-notes-1.0.1.xsl"
4112 xpointer="xpointer(/article/*)"/>
4115 <title>Version 0.9.2</title>
4117 xmlns:xi="http://www.w3.org/2001/XInclude"
4118 href="release-notes-0.9.2.xsl"
4119 xpointer="xpointer(/article/*)"/>
4122 <title>Version 0.9</title>
4124 xmlns:xi="http://www.w3.org/2001/XInclude"
4125 href="release-notes-0.9.xsl"
4126 xpointer="xpointer(/article/*)"/>
4129 <title>Version 0.8</title>
4131 xmlns:xi="http://www.w3.org/2001/XInclude"
4132 href="release-notes-0.8.xsl"
4133 xpointer="xpointer(/article/*)"/>
4136 <title>Version 0.7.1</title>
4138 xmlns:xi="http://www.w3.org/2001/XInclude"
4139 href="release-notes-0.7.1.xsl"
4140 xpointer="xpointer(/article/*)"/>
4145 <!-- LocalWords: Altusmetrum
projects / fw / altos / blob