1 <?xml version="1.0" encoding="utf-8"?>
2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
3 "/usr/share/xml/docbook/schema/dtd/4.5/docbookx.dtd">
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 <imagedata fileref="../themes/background.png" width="6.0in"/>
35 This document is released under the terms of the
36 <ulink url="http://creativecommons.org/licenses/by-sa/3.0/">
37 Creative Commons ShareAlike 3.0
44 <revnumber>1.4.1</revnumber>
45 <date>20 June 2014</date>
47 Minor release fixing some installation bugs.
51 <revnumber>1.4</revnumber>
52 <date>15 June 2014</date>
54 Major release adding TeleGPS support.
58 <revnumber>1.3.2</revnumber>
59 <date>24 January 2014</date>
61 Bug fixes for TeleMega and AltosUI.
65 <revnumber>1.3.1</revnumber>
66 <date>21 January 2014</date>
68 Bug fixes for TeleMega and TeleMetrum v2.0 along with a few
69 small UI improvements.
73 <revnumber>1.3</revnumber>
74 <date>12 November 2013</date>
76 Updated for software version 1.3. Version 1.3 adds support
77 for TeleMega, TeleMetrum v2.0, TeleMini v2.0 and EasyMini
78 and fixes bugs in AltosUI and the AltOS firmware.
82 <revnumber>1.2.1</revnumber>
83 <date>21 May 2013</date>
85 Updated for software version 1.2. Version 1.2 adds support
86 for TeleBT and AltosDroid. It also adds a few minor features
87 and fixes bugs in AltosUI and the AltOS firmware.
91 <revnumber>1.2</revnumber>
92 <date>18 April 2013</date>
94 Updated for software version 1.2. Version 1.2 adds support
95 for MicroPeak and the MicroPeak USB interface.
99 <revnumber>1.1.1</revnumber>
100 <date>16 September 2012</date>
102 Updated for software version 1.1.1 Version 1.1.1 fixes a few
103 bugs found in version 1.1.
107 <revnumber>1.1</revnumber>
108 <date>13 September 2012</date>
110 Updated for software version 1.1. Version 1.1 has new
111 features but is otherwise compatible with version 1.0.
115 <revnumber>1.0</revnumber>
116 <date>24 August 2011</date>
118 Updated for software version 1.0. Note that 1.0 represents a
119 telemetry format change, meaning both ends of a link
120 (TeleMetrum/TeleMini and TeleDongle) must be updated or
121 communications will fail.
125 <revnumber>0.9</revnumber>
126 <date>18 January 2011</date>
128 Updated for software version 0.9. Note that 0.9 represents a
129 telemetry format change, meaning both ends of a link (TeleMetrum and
130 TeleDongle) must be updated or communications will fail.
134 <revnumber>0.8</revnumber>
135 <date>24 November 2010</date>
136 <revremark>Updated for software version 0.8 </revremark>
141 <title>Acknowledgments</title>
143 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing “The
144 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
145 Kit” which formed the basis of the original Getting Started chapter
146 in this manual. Bob was one of our first customers for a production
147 TeleMetrum, and his continued enthusiasm and contributions
148 are immensely gratifying and highly appreciated!
151 And thanks to Anthony (AJ) Towns for major contributions including
152 the AltosUI graphing and site map code and associated documentation.
153 Free software means that our customers and friends can become our
154 collaborators, and we certainly appreciate this level of
158 Have fun using these products, and we hope to meet all of you
159 out on the rocket flight line somewhere.
162 NAR #87103, TRA #12201
164 Keith Packard, KD7SQG
165 NAR #88757, TRA #12200
170 <title>Introduction and Overview</title>
172 Welcome to the Altus Metrum community! Our circuits and software reflect
173 our passion for both hobby rocketry and Free Software. We hope their
174 capabilities and performance will delight you in every way, but by
175 releasing all of our hardware and software designs under open licenses,
176 we also hope to empower you to take as active a role in our collective
180 The first device created for our community was TeleMetrum, a dual
181 deploy altimeter with fully integrated GPS and radio telemetry
182 as standard features, and a “companion interface” that will
183 support optional capabilities in the future. The latest version
184 of TeleMetrum, v2.0, has all of the same features but with
185 improved sensors and radio to offer increased performance.
188 Our second device was TeleMini, a dual deploy altimeter with
189 radio telemetry and radio direction finding. The first version
190 of this device was only 13mm by 38mm (½ inch by 1½ inches) and
191 could fit easily in an 18mm air-frame. The latest version, v2.0,
192 includes a beeper, USB data download and extended on-board
193 flight logging, along with an improved barometric sensor.
196 TeleMega is our most sophisticated device, including six pyro
197 channels (four of which are fully programmable), integrated GPS,
198 integrated gyroscopes for staging/air-start inhibit and high
199 performance telemetry.
202 EasyMini is a dual-deploy altimeter with logging and built-in
206 TeleDongle was our first ground station, providing a USB to RF
207 interfaces for communicating with the altimeters. Combined with
208 your choice of antenna and notebook computer, TeleDongle and our
209 associated user interface software form a complete ground
210 station capable of logging and displaying in-flight telemetry,
211 aiding rocket recovery, then processing and archiving flight
212 data for analysis and review.
215 For a slightly more portable ground station experience that also
216 provides direct rocket recovery support, TeleBT offers flight
217 monitoring and data logging using a Bluetooth™ connection between
218 the receiver and an Android device that has the AltosDroid
219 application installed from the Google Play store.
222 More products will be added to the Altus Metrum family over time, and
223 we currently envision that this will be a single, comprehensive manual
224 for the entire product family.
228 <title>Getting Started</title>
230 The first thing to do after you check the inventory of parts in your
231 “starter kit” is to charge the battery.
234 For TeleMetrum and TeleMega, the battery can be charged by plugging it into the
235 corresponding socket of the device and then using the USB
236 cable to plug the flight computer into your computer's USB socket. The
237 on-board circuitry will charge the battery whenever it is plugged
238 in, because the on-off switch does NOT control the
242 On TeleMetrum v1 boards, when the GPS chip is initially
243 searching for satellites, TeleMetrum will consume more current
244 than it pulls from the USB port, so the battery must be
245 attached in order to get satellite lock. Once GPS is locked,
246 the current consumption goes back down enough to enable charging
247 while running. So it's a good idea to fully charge the battery
248 as your first item of business so there is no issue getting and
249 maintaining satellite lock. The yellow charge indicator led
250 will go out when the battery is nearly full and the charger goes
251 to trickle charge. It can take several hours to fully recharge a
252 deeply discharged battery.
255 TeleMetrum v2.0 and TeleMega use a higher power battery charger,
256 allowing them to charge the battery while running the board at
257 maximum power. When the battery is charging, or when the board
258 is consuming a lot of power, the red LED will be lit. When the
259 battery is fully charged, the green LED will be lit. When the
260 battery is damaged or missing, both LEDs will be lit, which
264 The Lithium Polymer TeleMini and EasyMini battery can be charged by
265 disconnecting it from the board and plugging it into a
266 standalone battery charger such as the LipoCharger product
267 included in TeleMini Starter Kits, and connecting that via a USB
268 cable to a laptop or other USB power source.
271 You can also choose to use another battery with TeleMini v2.0
272 and EasyMini, anything supplying between 4 and 12 volts should
273 work fine (like a standard 9V battery), but if you are planning
274 to fire pyro charges, ground testing is required to verify that
275 the battery supplies enough current to fire your chosen e-matches.
278 The other active device in the starter kit is the TeleDongle USB to
279 RF interface. If you plug it in to your Mac or Linux computer it should
280 “just work”, showing up as a serial port device. Windows systems need
281 driver information that is part of the AltOS download to know that the
282 existing USB modem driver will work. We therefore recommend installing
283 our software before plugging in TeleDongle if you are using a Windows
284 computer. If you are using an older version of Linux and are having
285 problems, try moving to a fresher kernel (2.6.33 or newer).
288 Next you should obtain and install the AltOS software. The AltOS
289 distribution includes the AltosUI ground station program, current
291 images for all of the hardware, and a number of standalone
292 utilities that are rarely needed. Pre-built binary packages are
293 available for Linux, Microsoft Windows, and recent MacOSX
294 versions. Full source code and build instructions are also
295 available. The latest version may always be downloaded from
296 <ulink url="http://altusmetrum.org/AltOS"/>.
299 If you're using a TeleBT instead of the TeleDongle, you'll want to
300 install the AltosDroid application from the Google Play store on an
301 Android device. You don't need a data plan to use AltosDroid, but
302 without network access, the Map view will be less useful as it
303 won't contain any map data. You can also use TeleBT connected
304 over USB with your laptop computer; it acts exactly like a
305 TeleDongle. Anywhere this manual talks about TeleDongle, you can
306 also read that as 'and TeleBT when connected via USB'.
310 <title>Handling Precautions</title>
312 All Altus Metrum products are sophisticated electronic devices.
313 When handled gently and properly installed in an air-frame, they
314 will deliver impressive results. However, as with all electronic
315 devices, there are some precautions you must take.
318 The Lithium Polymer rechargeable batteries have an
319 extraordinary power density. This is great because we can fly with
320 much less battery mass than if we used alkaline batteries or previous
321 generation rechargeable batteries... but if they are punctured
322 or their leads are allowed to short, they can and will release their
324 Thus we recommend that you take some care when handling our batteries
325 and consider giving them some extra protection in your air-frame. We
326 often wrap them in suitable scraps of closed-cell packing foam before
327 strapping them down, for example.
330 The barometric sensors used on all of our flight computers are
331 sensitive to sunlight. In normal mounting situations, the baro sensor
332 and all of the other surface mount components
333 are “down” towards whatever the underlying mounting surface is, so
334 this is not normally a problem. Please consider this when designing an
335 installation in an air-frame with a see-through plastic payload bay. It
336 is particularly important to
337 consider this with TeleMini v1.0, both because the baro sensor is on the
338 “top” of the board, and because many model rockets with payload bays
339 use clear plastic for the payload bay! Replacing these with an opaque
340 cardboard tube, painting them, or wrapping them with a layer of masking
341 tape are all reasonable approaches to keep the sensor out of direct
345 The barometric sensor sampling port must be able to “breathe”,
346 both by not being covered by foam or tape or other materials that might
347 directly block the hole on the top of the sensor, and also by having a
348 suitable static vent to outside air.
351 As with all other rocketry electronics, Altus Metrum altimeters must
352 be protected from exposure to corrosive motor exhaust and ejection
357 <title>Altus Metrum Hardware</title>
359 <title>General Usage Instructions</title>
361 Here are general instructions for hooking up an Altus Metrum
362 flight computer. Instructions specific to each model will be
363 found in the section devoted to that model below.
366 To prevent electrical interference from affecting the
367 operation of the flight computer, it's important to always
368 twist pairs of wires connected to the board. Twist the switch
369 leads, the pyro leads and the battery leads. This reduces
370 interference through a mechanism called common mode rejection.
373 <title>Hooking Up Lithium Polymer Batteries</title>
375 All Altus Metrum flight computers have a two pin JST PH
376 series connector to connect up a single-cell Lithium Polymer
377 cell (3.7V nominal). You can purchase matching batteries
378 from the Altus Metrum store, or other vendors, or you can
379 make your own. Pin 1 of the connector is positive, pin 2 is
380 negative. Spark Fun sells a cable with the connector
381 attached, which they call a <ulink
382 url="https://www.sparkfun.com/products/9914">JST Jumper 2
383 Wire Assembly</ulink>.
386 Many RC vendors also sell lithium polymer batteries with
387 this same connector. All that we have found use the opposite
388 polarity, and if you use them that way, you will damage or
389 destroy the flight computer.
393 <title>Hooking Up Pyro Charges</title>
395 Altus Metrum flight computers always have two screws for
396 each pyro charge. This means you shouldn't need to put two
397 wires into a screw terminal or connect leads from pyro
398 charges together externally.
401 On the flight computer, one lead from each charge is hooked
402 to the positive battery terminal through the power switch.
403 The other lead is connected through the pyro circuit, which
404 is connected to the negative battery terminal when the pyro
409 <title>Hooking Up a Power Switch</title>
411 Altus Metrum flight computers need an external power switch
412 to turn them on. This disconnects both the computer and the
413 pyro charges from the battery, preventing the charges from
414 firing when in the Off position. The switch is in-line with
415 the positive battery terminal.
418 <title>Using an External Active Switch Circuit</title>
420 You can use an active switch circuit, such as the
421 Featherweight Magnetic Switch, with any Altus Metrum
422 flight computer. These require three connections, one to
423 the battery, one to the positive power input on the flight
424 computer and one to ground. Find instructions on how to
425 hook these up for each flight computer below. The follow
426 the instructions that come with your active switch to
432 <title>Using a Separate Pyro Battery</title>
434 As mentioned above in the section on hooking up pyro
435 charges, one lead for each of the pyro charges is connected
436 through the power switch directly to the positive battery
437 terminal. The other lead is connected to the pyro circuit,
438 which connects it to the negative battery terminal when the
439 pyro circuit is fired. The pyro circuit on all of the flight
440 computers is designed to handle up to 16V.
443 To use a separate pyro battery, connect the negative pyro
444 battery terminal to the flight computer ground terminal,
445 the positive battery terminal to the igniter and the other
446 igniter lead to the negative pyro terminal on the flight
447 computer. When the pyro channel fires, it will complete the
448 circuit between the negative pyro terminal and the ground
449 terminal, firing the igniter. Specific instructions on how
450 to hook this up will be found in each section below.
454 <title>Using a Different Kind of Battery</title>
456 EasyMini and TeleMini v2 are designed to use either a
457 lithium polymer battery or any other battery producing
458 between 4 and 12 volts, such as a rectangular 9V
459 battery. TeleMega and TeleMetrum are not designed for this,
460 and must only be powered by a lithium polymer battery. Find
461 instructions on how to use other batteries in the EasyMini
462 and TeleMini sections below.
467 <title>Specifications</title>
469 Here's the full set of Altus Metrum products, both in
470 production and retired.
473 <title>Altus Metrum Electronics</title>
474 <?dbfo keep-together="always"?>
475 <tgroup cols='8' align='center' colsep='1' rowsep='1'>
476 <colspec align='center' colwidth='*' colname='Device'/>
477 <colspec align='center' colwidth='*' colname='Barometer'/>
478 <colspec align='center' colwidth='*' colname='Z-axis accelerometer'/>
479 <colspec align='center' colwidth='*' colname='GPS'/>
480 <colspec align='center' colwidth='*' colname='3D sensors'/>
481 <colspec align='center' colwidth='*' colname='Storage'/>
482 <colspec align='center' colwidth='*' colname='RF'/>
483 <colspec align='center' colwidth='*' colname='Battery'/>
486 <entry align='center'>Device</entry>
487 <entry align='center'>Barometer</entry>
488 <entry align='center'>Z-axis accelerometer</entry>
489 <entry align='center'>GPS</entry>
490 <entry align='center'>3D sensors</entry>
491 <entry align='center'>Storage</entry>
492 <entry align='center'>RF Output</entry>
493 <entry align='center'>Battery</entry>
498 <entry>TeleMetrum v1.0</entry>
499 <entry><para>MP3H6115 10km (33k')</para></entry>
500 <entry><para>MMA2202 50g</para></entry>
501 <entry>SkyTraq</entry>
508 <entry>TeleMetrum v1.1</entry>
509 <entry><para>MP3H6115 10km (33k')</para></entry>
510 <entry><para>MMA2202 50g</para></entry>
511 <entry>SkyTraq</entry>
518 <entry>TeleMetrum v1.2</entry>
519 <entry><para>MP3H6115 10km (33k')</para></entry>
520 <entry><para>ADXL78 70g</para></entry>
521 <entry>SkyTraq</entry>
528 <entry>TeleMetrum v2.0</entry>
529 <entry><para>MS5607 30km (100k')</para></entry>
530 <entry><para>MMA6555 102g</para></entry>
531 <entry>uBlox Max-7Q</entry>
538 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
539 <entry><para>MP3H6115 10km (33k')</para></entry>
548 <entry>TeleMini <?linebreak?>v2.0</entry>
549 <entry><para>MS5607 30km (100k')</para></entry>
555 <entry>3.7-12V</entry>
558 <entry>EasyMini <?linebreak?>v1.0</entry>
559 <entry><para>MS5607 30km (100k')</para></entry>
565 <entry>3.7-12V</entry>
568 <entry>TeleMega <?linebreak?>v1.0</entry>
569 <entry><para>MS5607 30km (100k')</para></entry>
570 <entry><para>MMA6555 102g</para></entry>
571 <entry>uBlox Max-7Q</entry>
572 <entry><para>MPU6000 HMC5883</para></entry>
581 <title>Altus Metrum Boards</title>
582 <?dbfo keep-together="always"?>
583 <tgroup cols='6' align='center' colsep='1' rowsep='1'>
584 <colspec align='center' colwidth='*' colname='Device'/>
585 <colspec align='center' colwidth='*' colname='Connectors'/>
586 <colspec align='center' colwidth='*' colname='Screw Terminals'/>
587 <colspec align='center' colwidth='*' colname='Width'/>
588 <colspec align='center' colwidth='*' colname='Length'/>
589 <colspec align='center' colwidth='*' colname='Tube Size'/>
592 <entry align='center'>Device</entry>
593 <entry align='center'>Connectors</entry>
594 <entry align='center'>Screw Terminals</entry>
595 <entry align='center'>Width</entry>
596 <entry align='center'>Length</entry>
597 <entry align='center'>Tube Size</entry>
602 <entry>TeleMetrum</entry>
606 Companion<?linebreak?>
610 <entry><para>Apogee pyro <?linebreak?>Main pyro <?linebreak?>Switch</para></entry>
611 <entry>1 inch (2.54cm)</entry>
612 <entry>2 ¾ inch (6.99cm)</entry>
613 <entry>29mm coupler</entry>
616 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
623 Apogee pyro <?linebreak?>
626 <entry>½ inch (1.27cm)</entry>
627 <entry>1½ inch (3.81cm)</entry>
628 <entry>18mm coupler</entry>
631 <entry>TeleMini <?linebreak?>v2.0</entry>
639 Apogee pyro <?linebreak?>
640 Main pyro <?linebreak?>
641 Battery <?linebreak?>
644 <entry>0.8 inch (2.03cm)</entry>
645 <entry>1½ inch (3.81cm)</entry>
646 <entry>24mm coupler</entry>
649 <entry>EasyMini</entry>
656 Apogee pyro <?linebreak?>
657 Main pyro <?linebreak?>
658 Battery <?linebreak?>
661 <entry>0.8 inch (2.03cm)</entry>
662 <entry>1½ inch (3.81cm)</entry>
663 <entry>24mm coupler</entry>
666 <entry>TeleMega</entry>
670 Companion<?linebreak?>
675 Apogee pyro <?linebreak?>
676 Main pyro<?linebreak?>
677 Pyro A-D<?linebreak?>
681 <entry>1¼ inch (3.18cm)</entry>
682 <entry>3¼ inch (8.26cm)</entry>
683 <entry>38mm coupler</entry>
690 <title>TeleMetrum</title>
694 <imagedata fileref="telemetrum-v1.1-thside.jpg" width="5.5in" scalefit="1"/>
699 TeleMetrum is a 1 inch by 2¾ inch circuit board. It was designed to
700 fit inside coupler for 29mm air-frame tubing, but using it in a tube that
701 small in diameter may require some creativity in mounting and wiring
702 to succeed! The presence of an accelerometer means TeleMetrum should
703 be aligned along the flight axis of the airframe, and by default the ¼
704 wave UHF wire antenna should be on the nose-cone end of the board. The
705 antenna wire is about 7 inches long, and wiring for a power switch and
706 the e-matches for apogee and main ejection charges depart from the
707 fin can end of the board, meaning an ideal “simple” avionics
708 bay for TeleMetrum should have at least 10 inches of interior length.
711 <title>TeleMetrum Screw Terminals</title>
713 TeleMetrum has six screw terminals on the end of the board
714 opposite the telemetry antenna. Two are for the power
715 switch, and two each for the apogee and main igniter
716 circuits. Using the picture above and starting from the top,
717 the terminals are as follows:
720 <title>TeleMetrum Screw Terminals</title>
721 <?dbfo keep-together="always"?>
722 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
723 <colspec align='center' colwidth='*' colname='Pin #'/>
724 <colspec align='center' colwidth='2*' colname='Pin Name'/>
725 <colspec align='left' colwidth='5*' colname='Description'/>
728 <entry align='center'>Terminal #</entry>
729 <entry align='center'>Terminal Name</entry>
730 <entry align='center'>Description</entry>
736 <entry>Switch Output</entry>
737 <entry>Switch connection to flight computer</entry>
741 <entry>Switch Input</entry>
742 <entry>Switch connection to positive battery terminal</entry>
746 <entry>Main +</entry>
747 <entry>Main pyro channel common connection to battery +</entry>
751 <entry>Main -</entry>
752 <entry>Main pyro channel connection to pyro circuit</entry>
756 <entry>Apogee +</entry>
757 <entry>Apogee pyro channel common connection to battery +</entry>
761 <entry>Apogee -</entry>
762 <entry>Apogee pyro channel connection to pyro circuit</entry>
769 <title>Using a Separate Pyro Battery with TeleMetrum</title>
771 As described above, using an external pyro battery involves
772 connecting the negative battery terminal to the flight
773 computer ground, connecting the positive battery terminal to
774 one of the igniter leads and connecting the other igniter
775 lead to the per-channel pyro circuit connection.
778 To connect the negative battery terminal to the TeleMetrum
779 ground, insert a small piece of wire, 24 to 28 gauge
780 stranded, into the GND hole just above the screw terminal
781 strip and solder it in place.
784 Connecting the positive battery terminal to the pyro
785 charges must be done separate from TeleMetrum, by soldering
786 them together or using some other connector.
789 The other lead from each pyro charge is then inserted into
790 the appropriate per-pyro channel screw terminal (terminal 4 for the
791 Main charge, terminal 6 for the Apogee charge).
795 <title>Using an Active Switch with TeleMetrum</title>
797 As explained above, an external active switch requires three
798 connections, one to the positive battery terminal, one to
799 the flight computer positive input and one to ground.
802 The positive battery terminal is available on screw terminal
803 2, the positive flight computer input is on terminal 1. To
804 hook a lead to ground, solder a piece of wire, 24 to 28
805 gauge stranded, to the GND hole just above terminal 1.
810 <title>TeleMini v1.0</title>
814 <imagedata fileref="telemini-v1-top.jpg" width="5.5in" scalefit="1"/>
819 TeleMini v1.0 is ½ inches by 1½ inches. It was
820 designed to fit inside an 18mm air-frame tube, but using it in
821 a tube that small in diameter may require some creativity in
822 mounting and wiring to succeed! Since there is no
823 accelerometer, TeleMini can be mounted in any convenient
824 orientation. The default ¼ wave UHF wire antenna attached to
825 the center of one end of the board is about 7 inches long. Two
826 wires for the power switch are connected to holes in the
827 middle of the board. Screw terminals for the e-matches for
828 apogee and main ejection charges depart from the other end of
829 the board, meaning an ideal “simple” avionics bay for TeleMini
830 should have at least 9 inches of interior length.
833 <title>TeleMini v1.0 Screw Terminals</title>
835 TeleMini v1.0 has four screw terminals on the end of the
836 board opposite the telemetry antenna. Two are for the apogee
837 and two are for main igniter circuits. There are also wires
838 soldered to the board for the power switch. Using the
839 picture above and starting from the top for the terminals
840 and from the left for the power switch wires, the
841 connections are as follows:
844 <title>TeleMini v1.0 Connections</title>
845 <?dbfo keep-together="always"?>
846 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
847 <colspec align='center' colwidth='*' colname='Pin #'/>
848 <colspec align='center' colwidth='2*' colname='Pin Name'/>
849 <colspec align='left' colwidth='5*' colname='Description'/>
852 <entry align='center'>Terminal #</entry>
853 <entry align='center'>Terminal Name</entry>
854 <entry align='center'>Description</entry>
860 <entry>Apogee -</entry>
861 <entry>Apogee pyro channel connection to pyro circuit</entry>
865 <entry>Apogee +</entry>
866 <entry>Apogee pyro channel common connection to battery +</entry>
870 <entry>Main -</entry>
871 <entry>Main pyro channel connection to pyro circuit</entry>
875 <entry>Main +</entry>
876 <entry>Main pyro channel common connection to battery +</entry>
880 <entry>Switch Output</entry>
881 <entry>Switch connection to flight computer</entry>
885 <entry>Switch Input</entry>
886 <entry>Switch connection to positive battery terminal</entry>
893 <title>Using a Separate Pyro Battery with TeleMini v1.0</title>
895 As described above, using an external pyro battery involves
896 connecting the negative battery terminal to the flight
897 computer ground, connecting the positive battery terminal to
898 one of the igniter leads and connecting the other igniter
899 lead to the per-channel pyro circuit connection. Because
900 there is no solid ground connection to use on TeleMini, this
904 The only available ground connection on TeleMini v1.0 are
905 the two mounting holes next to the telemetry
906 antenna. Somehow connect a small piece of wire to one of
907 those holes and hook it to the negative pyro battery terminal.
910 Connecting the positive battery terminal to the pyro
911 charges must be done separate from TeleMini v1.0, by soldering
912 them together or using some other connector.
915 The other lead from each pyro charge is then inserted into
916 the appropriate per-pyro channel screw terminal (terminal 3 for the
917 Main charge, terminal 1 for the Apogee charge).
921 <title>Using an Active Switch with TeleMini v1.0</title>
923 As explained above, an external active switch requires three
924 connections, one to the positive battery terminal, one to
925 the flight computer positive input and one to ground. Again,
926 because TeleMini doesn't have any good ground connection,
927 this is not recommended.
930 The positive battery terminal is available on the Right
931 power switch wire, the positive flight computer input is on
932 the left power switch wire. Hook a lead to either of the
933 mounting holes for a ground connection.
938 <title>TeleMini v2.0</title>
942 <imagedata fileref="telemini-v2-top.jpg" width="5.5in" scalefit="1"/>
947 TeleMini v2.0 is 0.8 inches by 1½ inches. It adds more
948 on-board data logging memory, a built-in USB connector and
949 screw terminals for the battery and power switch. The larger
950 board fits in a 24mm coupler. There's also a battery connector
951 for a LiPo battery if you want to use one of those.
954 <title>TeleMini v2.0 Screw Terminals</title>
956 TeleMini v2.0 has two sets of four screw terminals on the end of the
957 board opposite the telemetry antenna. Using the picture
958 above, the top four have connections for the main pyro
959 circuit and an external battery and the bottom four have
960 connections for the apogee pyro circuit and the power
961 switch. Counting from the left, the connections are as follows:
964 <title>TeleMini v2.0 Connections</title>
965 <?dbfo keep-together="always"?>
966 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
967 <colspec align='center' colwidth='*' colname='Pin #'/>
968 <colspec align='center' colwidth='2*' colname='Pin Name'/>
969 <colspec align='left' colwidth='5*' colname='Description'/>
972 <entry align='center'>Terminal #</entry>
973 <entry align='center'>Terminal Name</entry>
974 <entry align='center'>Description</entry>
980 <entry>Main -</entry>
981 <entry>Main pyro channel connection to pyro circuit</entry>
985 <entry>Main +</entry>
986 <entry>Main pyro channel common connection to battery +</entry>
990 <entry>Battery +</entry>
991 <entry>Positive external battery terminal</entry>
995 <entry>Battery -</entry>
996 <entry>Negative external battery terminal</entry>
999 <entry>Bottom 1</entry>
1000 <entry>Apogee -</entry>
1001 <entry>Apogee pyro channel connection to pyro circuit</entry>
1004 <entry>Bottom 2</entry>
1005 <entry>Apogee +</entry>
1006 <entry>Apogee pyro channel common connection to
1010 <entry>Bottom 3</entry>
1011 <entry>Switch Output</entry>
1012 <entry>Switch connection to flight computer</entry>
1015 <entry>Bottom 4</entry>
1016 <entry>Switch Input</entry>
1017 <entry>Switch connection to positive battery terminal</entry>
1024 <title>Using a Separate Pyro Battery with TeleMini v2.0</title>
1026 As described above, using an external pyro battery involves
1027 connecting the negative battery terminal to the flight
1028 computer ground, connecting the positive battery terminal to
1029 one of the igniter leads and connecting the other igniter
1030 lead to the per-channel pyro circuit connection.
1033 To connect the negative pyro battery terminal to TeleMini
1034 ground, connect it to the negative external battery
1035 connection, top terminal 4.
1038 Connecting the positive battery terminal to the pyro
1039 charges must be done separate from TeleMini v2.0, by soldering
1040 them together or using some other connector.
1043 The other lead from each pyro charge is then inserted into
1044 the appropriate per-pyro channel screw terminal (top
1045 terminal 1 for the Main charge, bottom terminal 1 for the
1050 <title>Using an Active Switch with TeleMini v2.0</title>
1052 As explained above, an external active switch requires three
1053 connections, one to the positive battery terminal, one to
1054 the flight computer positive input and one to ground. Use
1055 the negative external battery connection, top terminal 4 for
1059 The positive battery terminal is available on bottom
1060 terminal 4, the positive flight computer input is on the
1066 <title>EasyMini</title>
1070 <imagedata fileref="easymini-top.jpg" width="5.5in" scalefit="1"/>
1075 EasyMini is built on a 0.8 inch by 1½ inch circuit board. It's
1076 designed to fit in a 24mm coupler tube. The connectors and
1077 screw terminals match TeleMini v2.0, so you can easily swap between
1078 EasyMini and TeleMini.
1081 <title>EasyMini Screw Terminals</title>
1083 EasyMini has two sets of four screw terminals on the end of the
1084 board opposite the telemetry antenna. Using the picture
1085 above, the top four have connections for the main pyro
1086 circuit and an external battery and the bottom four have
1087 connections for the apogee pyro circuit and the power
1088 switch. Counting from the left, the connections are as follows:
1091 <title>EasyMini Connections</title>
1092 <?dbfo keep-together="always"?>
1093 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
1094 <colspec align='center' colwidth='*' colname='Pin #'/>
1095 <colspec align='center' colwidth='2*' colname='Pin Name'/>
1096 <colspec align='left' colwidth='5*' colname='Description'/>
1099 <entry align='center'>Terminal #</entry>
1100 <entry align='center'>Terminal Name</entry>
1101 <entry align='center'>Description</entry>
1106 <entry>Top 1</entry>
1107 <entry>Main -</entry>
1108 <entry>Main pyro channel connection to pyro circuit</entry>
1111 <entry>Top 2</entry>
1112 <entry>Main +</entry>
1113 <entry>Main pyro channel common connection to battery +</entry>
1116 <entry>Top 3</entry>
1117 <entry>Battery +</entry>
1118 <entry>Positive external battery terminal</entry>
1121 <entry>Top 4</entry>
1122 <entry>Battery -</entry>
1123 <entry>Negative external battery terminal</entry>
1126 <entry>Bottom 1</entry>
1127 <entry>Apogee -</entry>
1128 <entry>Apogee pyro channel connection to pyro circuit</entry>
1131 <entry>Bottom 2</entry>
1132 <entry>Apogee +</entry>
1133 <entry>Apogee pyro channel common connection to
1137 <entry>Bottom 3</entry>
1138 <entry>Switch Output</entry>
1139 <entry>Switch connection to flight computer</entry>
1142 <entry>Bottom 4</entry>
1143 <entry>Switch Input</entry>
1144 <entry>Switch connection to positive battery terminal</entry>
1151 <title>Using a Separate Pyro Battery with EasyMini</title>
1153 As described above, using an external pyro battery involves
1154 connecting the negative battery terminal to the flight
1155 computer ground, connecting the positive battery terminal to
1156 one of the igniter leads and connecting the other igniter
1157 lead to the per-channel pyro circuit connection.
1160 To connect the negative pyro battery terminal to TeleMini
1161 ground, connect it to the negative external battery
1162 connection, top terminal 4.
1165 Connecting the positive battery terminal to the pyro
1166 charges must be done separate from EasyMini, by soldering
1167 them together or using some other connector.
1170 The other lead from each pyro charge is then inserted into
1171 the appropriate per-pyro channel screw terminal (top
1172 terminal 1 for the Main charge, bottom terminal 1 for the
1177 <title>Using an Active Switch with EasyMini</title>
1179 As explained above, an external active switch requires three
1180 connections, one to the positive battery terminal, one to
1181 the flight computer positive input and one to ground. Use
1182 the negative external battery connection, top terminal 4 for
1186 The positive battery terminal is available on bottom
1187 terminal 4, the positive flight computer input is on the
1193 <title>TeleMega</title>
1197 <imagedata fileref="telemega-v1.0-top.jpg" width="5.5in" scalefit="1"/>
1202 TeleMega is a 1¼ inch by 3¼ inch circuit board. It was
1203 designed to easily fit in a 38mm coupler. Like TeleMetrum,
1204 TeleMega has an accelerometer and so it must be mounted so that
1205 the board is aligned with the flight axis. It can be mounted
1206 either antenna up or down.
1209 <title>TeleMega Screw Terminals</title>
1211 TeleMega has two sets of nine screw terminals on the end of
1212 the board opposite the telemetry antenna. They are as follows:
1215 <title>TeleMega Screw Terminals</title>
1216 <?dbfo keep-together="always"?>
1217 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
1218 <colspec align='center' colwidth='*' colname='Pin #'/>
1219 <colspec align='center' colwidth='2*' colname='Pin Name'/>
1220 <colspec align='left' colwidth='5*' colname='Description'/>
1223 <entry align='center'>Terminal #</entry>
1224 <entry align='center'>Terminal Name</entry>
1225 <entry align='center'>Description</entry>
1230 <entry>Top 1</entry>
1231 <entry>Switch Input</entry>
1232 <entry>Switch connection to positive battery terminal</entry>
1235 <entry>Top 2</entry>
1236 <entry>Switch Output</entry>
1237 <entry>Switch connection to flight computer</entry>
1240 <entry>Top 3</entry>
1242 <entry>Ground connection for use with external active switch</entry>
1245 <entry>Top 4</entry>
1246 <entry>Main -</entry>
1247 <entry>Main pyro channel connection to pyro circuit</entry>
1250 <entry>Top 5</entry>
1251 <entry>Main +</entry>
1252 <entry>Main pyro channel common connection to battery +</entry>
1255 <entry>Top 6</entry>
1256 <entry>Apogee -</entry>
1257 <entry>Apogee pyro channel connection to pyro circuit</entry>
1260 <entry>Top 7</entry>
1261 <entry>Apogee +</entry>
1262 <entry>Apogee pyro channel common connection to battery +</entry>
1265 <entry>Top 8</entry>
1267 <entry>D pyro channel connection to pyro circuit</entry>
1270 <entry>Top 9</entry>
1272 <entry>D pyro channel common connection to battery +</entry>
1275 <entry>Bottom 1</entry>
1277 <entry>Ground connection for negative pyro battery terminal</entry>
1280 <entry>Bottom 2</entry>
1282 <entry>Positive pyro battery terminal</entry>
1285 <entry>Bottom 3</entry>
1288 Power switch output. Use to connect main battery to
1293 <entry>Bottom 4</entry>
1295 <entry>A pyro channel connection to pyro circuit</entry>
1298 <entry>Bottom 5</entry>
1300 <entry>A pyro channel common connection to battery +</entry>
1303 <entry>Bottom 6</entry>
1305 <entry>B pyro channel connection to pyro circuit</entry>
1308 <entry>Bottom 7</entry>
1310 <entry>B pyro channel common connection to battery +</entry>
1313 <entry>Bottom 8</entry>
1315 <entry>C pyro channel connection to pyro circuit</entry>
1318 <entry>Bottom 9</entry>
1320 <entry>C pyro channel common connection to battery +</entry>
1327 <title>Using a Separate Pyro Battery with TeleMega</title>
1329 TeleMega provides explicit support for an external pyro
1330 battery. All that is required is to remove the jumper
1331 between the lipo terminal (Bottom 3) and the pyro terminal
1332 (Bottom 2). Then hook the negative pyro battery terminal to ground
1333 (Bottom 1) and the positive pyro battery to the pyro battery
1334 input (Bottom 2). You can then use the existing pyro screw
1335 terminals to hook up all of the pyro charges.
1339 <title>Using Only One Battery With TeleMega</title>
1341 Because TeleMega has built-in support for a separate pyro
1342 battery, if you want to fly with just one battery running
1343 both the computer and firing the charges, you need to
1344 connect the flight computer battery to the pyro
1345 circuit. TeleMega has two screw terminals for this—hook a
1346 wire from the Lipo terminal (Bottom 3) to the Pyro terminal
1351 <title>Using an Active Switch with TeleMega</title>
1353 As explained above, an external active switch requires three
1354 connections, one to the positive battery terminal, one to
1355 the flight computer positive input and one to ground.
1358 The positive battery terminal is available on Top terminal
1359 1, the positive flight computer input is on Top terminal
1360 2. Ground is on Top terminal 3.
1365 <title>Flight Data Recording</title>
1367 Each flight computer logs data at 100 samples per second
1368 during ascent and 10 samples per second during descent, except
1369 for TeleMini v1.0, which records ascent at 10 samples per
1370 second and descent at 1 sample per second. Data are logged to
1371 an on-board flash memory part, which can be partitioned into
1372 several equal-sized blocks, one for each flight.
1375 <title>Data Storage on Altus Metrum altimeters</title>
1376 <?dbfo keep-together="always"?>
1377 <tgroup cols='4' align='center' colsep='1' rowsep='1'>
1378 <colspec align='center' colwidth='*' colname='Device'/>
1379 <colspec align='center' colwidth='*' colname='Bytes per sample'/>
1380 <colspec align='center' colwidth='*' colname='Total storage'/>
1381 <colspec align='center' colwidth='*' colname='Minutes of
1385 <entry align='center'>Device</entry>
1386 <entry align='center'>Bytes per Sample</entry>
1387 <entry align='center'>Total Storage</entry>
1388 <entry align='center'>Minutes at Full Rate</entry>
1393 <entry>TeleMetrum v1.0</entry>
1399 <entry>TeleMetrum v1.1 v1.2</entry>
1405 <entry>TeleMetrum v2.0</entry>
1411 <entry>TeleMini v1.0</entry>
1417 <entry>TeleMini v2.0</entry>
1423 <entry>EasyMini</entry>
1429 <entry>TeleMega</entry>
1438 The on-board flash is partitioned into separate flight logs,
1439 each of a fixed maximum size. Increase the maximum size of
1440 each log and you reduce the number of flights that can be
1441 stored. Decrease the size and you can store more flights.
1444 Configuration data is also stored in the flash memory on
1445 TeleMetrum v1.x, TeleMini and EasyMini. This consumes 64kB
1446 of flash space. This configuration space is not available
1447 for storing flight log data. TeleMetrum v2.0 and TeleMega
1448 store configuration data in a bit of eeprom available within
1449 the processor chip, leaving that space available in flash for
1453 To compute the amount of space needed for a single flight, you
1454 can multiply the expected ascent time (in seconds) by 100
1455 times bytes-per-sample, multiply the expected descent time (in
1456 seconds) by 10 times the bytes per sample and add the two
1457 together. That will slightly under-estimate the storage (in
1458 bytes) needed for the flight. For instance, a TeleMetrum v2.0 flight spending
1459 20 seconds in ascent and 150 seconds in descent will take
1460 about (20 * 1600) + (150 * 160) = 56000 bytes of storage. You
1461 could store dozens of these flights in the on-board flash.
1464 The default size allows for several flights on each flight
1465 computer, except for TeleMini v1.0, which only holds data for a
1466 single flight. You can adjust the size.
1469 Altus Metrum flight computers will not overwrite existing
1470 flight data, so be sure to download flight data and erase it
1471 from the flight computer before it fills up. The flight
1472 computer will still successfully control the flight even if it
1473 cannot log data, so the only thing you will lose is the data.
1477 <title>Installation</title>
1479 A typical installation involves attaching
1480 only a suitable battery, a single pole switch for
1481 power on/off, and two pairs of wires connecting e-matches for the
1482 apogee and main ejection charges. All Altus Metrum products are
1483 designed for use with single-cell batteries with 3.7 volts
1484 nominal. TeleMini v2.0 and EasyMini may also be used with other
1485 batteries as long as they supply between 4 and 12 volts.
1488 The battery connectors are a standard 2-pin JST connector and
1489 match batteries sold by Spark Fun. These batteries are
1490 single-cell Lithium Polymer batteries that nominally provide 3.7
1491 volts. Other vendors sell similar batteries for RC aircraft
1492 using mating connectors, however the polarity for those is
1493 generally reversed from the batteries used by Altus Metrum
1494 products. In particular, the Tenergy batteries supplied for use
1495 in Featherweight flight computers are not compatible with Altus
1496 Metrum flight computers or battery chargers. <emphasis>Check
1497 polarity and voltage before connecting any battery not purchased
1498 from Altus Metrum or Spark Fun.</emphasis>
1501 By default, we use the unregulated output of the battery directly
1502 to fire ejection charges. This works marvelously with standard
1503 low-current e-matches like the J-Tek from MJG Technologies, and with
1504 Quest Q2G2 igniters. However, if you want or need to use a separate
1505 pyro battery, check out the “External Pyro Battery” section in this
1506 manual for instructions on how to wire that up. The altimeters are
1507 designed to work with an external pyro battery of no more than 15 volts.
1510 Ejection charges are wired directly to the screw terminal block
1511 at the aft end of the altimeter. You'll need a very small straight
1512 blade screwdriver for these screws, such as you might find in a
1513 jeweler's screwdriver set.
1516 Except for TeleMini v1.0, the flight computers also use the
1517 screw terminal block for the power switch leads. On TeleMini v1.0,
1518 the power switch leads are soldered directly to the board and
1519 can be connected directly to a switch.
1522 For most air-frames, the integrated antennas are more than
1523 adequate. However, if you are installing in a carbon-fiber or
1524 metal electronics bay which is opaque to RF signals, you may need to
1525 use off-board external antennas instead. In this case, you can
1526 replace the stock UHF antenna wire with an edge-launched SMA connector,
1527 and, on TeleMetrum v1, you can unplug the integrated GPS
1528 antenna and select an appropriate off-board GPS antenna with
1529 cable terminating in a U.FL connector.
1534 <title>System Operation</title>
1536 <title>Firmware Modes </title>
1538 The AltOS firmware build for the altimeters has two
1539 fundamental modes, “idle” and “flight”. Which of these modes
1540 the firmware operates in is determined at start up time. For
1541 TeleMetrum and TeleMega, which have accelerometers, the mode is
1542 controlled by the orientation of the
1543 rocket (well, actually the board, of course...) at the time
1544 power is switched on. If the rocket is “nose up”, then
1545 the flight computer assumes it's on a rail or rod being prepared for
1546 launch, so the firmware chooses flight mode. However, if the
1547 rocket is more or less horizontal, the firmware instead enters
1548 idle mode. Since TeleMini v2.0 and EasyMini don't have an
1549 accelerometer we can use to determine orientation, “idle” mode
1550 is selected if the board is connected via USB to a computer,
1551 otherwise the board enters “flight” mode. TeleMini v1.0
1552 selects “idle” mode if it receives a command packet within the
1553 first five seconds of operation.
1556 At power on, the altimeter will beep out the battery voltage
1557 to the nearest tenth of a volt. Each digit is represented by
1558 a sequence of short “dit” beeps, with a pause between
1559 digits. A zero digit is represented with one long “dah”
1560 beep. Then there will be a short pause while the altimeter
1561 completes initialization and self test, and decides which mode
1565 Here's a short summary of all of the modes and the beeping (or
1566 flashing, in the case of TeleMini v1) that accompanies each
1567 mode. In the description of the beeping pattern, “dit” means a
1568 short beep while "dah" means a long beep (three times as
1569 long). “Brap” means a long dissonant tone.
1571 <title>AltOS Modes</title>
1572 <?dbfo keep-together="always"?>
1573 <tgroup cols='4' align='center' colsep='1' rowsep='1'>
1574 <colspec align='center' colwidth='*' colname='Mode Name'/>
1575 <colspec align='center' colwidth='*' colname='Letter'/>
1576 <colspec align='center' colwidth='*' colname='Beeps'/>
1577 <colspec align='center' colwidth='*' colname='Description'/>
1580 <entry>Mode Name</entry>
1581 <entry>Abbreviation</entry>
1582 <entry>Beeps</entry>
1583 <entry>Description</entry>
1588 <entry>Startup</entry>
1590 <entry>battery voltage in decivolts</entry>
1593 Calibrating sensors, detecting orientation.
1600 <entry>dit dit</entry>
1603 Ready to accept commands over USB or radio link.
1610 <entry>dit dah dah dit</entry>
1613 Waiting for launch. Not listening for commands.
1618 <entry>Boost</entry>
1620 <entry>dah dit dit dit</entry>
1623 Accelerating upwards.
1630 <entry>dit dit dah dit</entry>
1633 Decelerating, but moving faster than 200m/s.
1638 <entry>Coast</entry>
1640 <entry>dah dit dah dit</entry>
1643 Decelerating, moving slower than 200m/s
1648 <entry>Drogue</entry>
1650 <entry>dah dit dit</entry>
1653 Descending after apogee. Above main height.
1660 <entry>dah dah</entry>
1663 Descending. Below main height.
1668 <entry>Landed</entry>
1670 <entry>dit dah dit dit</entry>
1673 Stable altitude for at least ten seconds.
1678 <entry>Sensor error</entry>
1680 <entry>dah dit dit dah</entry>
1683 Error detected during sensor calibration.
1692 In flight or “pad” mode, the altimeter engages the flight
1693 state machine, goes into transmit-only mode to send telemetry,
1694 and waits for launch to be detected. Flight mode is indicated
1695 by an “di-dah-dah-dit” (“P” for pad) on the beeper or lights,
1696 followed by beeps or flashes indicating the state of the
1697 pyrotechnic igniter continuity. One beep/flash indicates
1698 apogee continuity, two beeps/flashes indicate main continuity,
1699 three beeps/flashes indicate both apogee and main continuity,
1700 and one longer “brap” sound which is made by rapidly
1701 alternating between two tones indicates no continuity. For a
1702 dual deploy flight, make sure you're getting three beeps or
1703 flashes before launching! For apogee-only or motor eject
1704 flights, do what makes sense.
1707 If idle mode is entered, you will hear an audible “di-dit” or
1708 see two short flashes (“I” for idle), and the flight state
1709 machine is disengaged, thus no ejection charges will fire.
1710 The altimeters also listen for the radio link when in idle
1711 mode for requests sent via TeleDongle. Commands can be issued
1712 in idle mode over either USB or the radio link
1713 equivalently. TeleMini v1.0 only has the radio link. Idle
1714 mode is useful for configuring the altimeter, for extracting
1715 data from the on-board storage chip after flight, and for
1716 ground testing pyro charges.
1719 In “Idle” and “Pad” modes, once the mode indication
1720 beeps/flashes and continuity indication has been sent, if
1721 there is no space available to log the flight in on-board
1722 memory, the flight computer will emit a warbling tone (much
1723 slower than the “no continuity tone”)
1726 Here's a summary of all of the “pad” and “idle” mode indications.
1728 <title>Pad/Idle Indications</title>
1729 <?dbfo keep-together="always"?>
1730 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
1731 <colspec align='center' colwidth='*' colname='Name'/>
1732 <colspec align='center' colwidth='*' colname='Beeps'/>
1733 <colspec align='center' colwidth='*' colname='Description'/>
1737 <entry>Beeps</entry>
1738 <entry>Description</entry>
1743 <entry>Neither</entry>
1747 No continuity detected on either apogee or main
1753 <entry>Apogee</entry>
1757 Continuity detected only on apogee igniter.
1763 <entry>dit dit</entry>
1766 Continuity detected only on main igniter.
1772 <entry>dit dit dit</entry>
1775 Continuity detected on both igniters.
1780 <entry>Storage Full</entry>
1781 <entry>warble</entry>
1784 On-board data logging storage is full. This will
1785 not prevent the flight computer from safely
1786 controlling the flight or transmitting telemetry
1787 signals, but no record of the flight will be
1788 stored in on-board flash.
1797 Once landed, the flight computer will signal that by emitting
1798 the “Landed” sound described above, after which it will beep
1799 out the apogee height (in meters). Each digit is represented
1800 by a sequence of short “dit” beeps, with a pause between
1801 digits. A zero digit is represented with one long “dah”
1802 beep. The flight computer will continue to report landed mode
1803 and beep out the maximum height until turned off.
1806 One “neat trick” of particular value when TeleMetrum or TeleMega are used with
1807 very large air-frames, is that you can power the board up while the
1808 rocket is horizontal, such that it comes up in idle mode. Then you can
1809 raise the air-frame to launch position, and issue a 'reset' command
1810 via TeleDongle over the radio link to cause the altimeter to reboot and
1811 come up in flight mode. This is much safer than standing on the top
1812 step of a rickety step-ladder or hanging off the side of a launch
1813 tower with a screw-driver trying to turn on your avionics before
1814 installing igniters!
1817 TeleMini v1.0 is configured solely via the radio link. Of course, that
1818 means you need to know the TeleMini radio configuration values
1819 or you won't be able to communicate with it. For situations
1820 when you don't have the radio configuration values, TeleMini v1.0
1821 offers an 'emergency recovery' mode. In this mode, TeleMini is
1822 configured as follows:
1826 Sets the radio frequency to 434.550MHz
1831 Sets the radio calibration back to the factory value.
1836 Sets the callsign to N0CALL
1841 Does not go to 'pad' mode after five seconds.
1847 To get into 'emergency recovery' mode, first find the row of
1848 four small holes opposite the switch wiring. Using a short
1849 piece of small gauge wire, connect the outer two holes
1850 together, then power TeleMini up. Once the red LED is lit,
1851 disconnect the wire and the board should signal that it's in
1852 'idle' mode after the initial five second startup period.
1858 TeleMetrum and TeleMega include a complete GPS receiver. A
1859 complete explanation of how GPS works is beyond the scope of
1860 this manual, but the bottom line is that the GPS receiver
1861 needs to lock onto at least four satellites to obtain a solid
1862 3 dimensional position fix and know what time it is.
1865 The flight computers provide backup power to the GPS chip any time a
1866 battery is connected. This allows the receiver to “warm start” on
1867 the launch rail much faster than if every power-on were a GPS
1868 “cold start”. In typical operations, powering up
1869 on the flight line in idle mode while performing final air-frame
1870 preparation will be sufficient to allow the GPS receiver to cold
1871 start and acquire lock. Then the board can be powered down during
1872 RSO review and installation on a launch rod or rail. When the board
1873 is turned back on, the GPS system should lock very quickly, typically
1874 long before igniter installation and return to the flight line are
1879 <title>Controlling An Altimeter Over The Radio Link</title>
1881 One of the unique features of the Altus Metrum system is the
1882 ability to create a two way command link between TeleDongle
1883 and an altimeter using the digital radio transceivers
1884 built into each device. This allows you to interact with the
1885 altimeter from afar, as if it were directly connected to the
1889 Any operation which can be performed with a flight computer can
1890 either be done with the device directly connected to the
1891 computer via the USB cable, or through the radio
1892 link. TeleMini v1.0 doesn't provide a USB connector and so it is
1893 always communicated with over radio. Select the appropriate
1894 TeleDongle device when the list of devices is presented and
1895 AltosUI will interact with an altimeter over the radio link.
1898 One oddity in the current interface is how AltosUI selects the
1899 frequency for radio communications. Instead of providing
1900 an interface to specifically configure the frequency, it uses
1901 whatever frequency was most recently selected for the target
1902 TeleDongle device in Monitor Flight mode. If you haven't ever
1903 used that mode with the TeleDongle in question, select the
1904 Monitor Flight button from the top level UI, and pick the
1905 appropriate TeleDongle device. Once the flight monitoring
1906 window is open, select the desired frequency and then close it
1907 down again. All radio communications will now use that frequency.
1912 Save Flight Data—Recover flight data from the rocket without
1918 Configure altimeter apogee delays, main deploy heights
1919 and additional pyro event conditions
1920 to respond to changing launch conditions. You can also
1921 'reboot' the altimeter. Use this to remotely enable the
1922 flight computer by turning TeleMetrum or TeleMega on in “idle” mode,
1923 then once the air-frame is oriented for launch, you can
1924 reboot the altimeter and have it restart in pad mode
1925 without having to climb the scary ladder.
1930 Fire Igniters—Test your deployment charges without snaking
1931 wires out through holes in the air-frame. Simply assemble the
1932 rocket as if for flight with the apogee and main charges
1933 loaded, then remotely command the altimeter to fire the
1939 Operation over the radio link for configuring an altimeter, ground
1940 testing igniters, and so forth uses the same RF frequencies as flight
1941 telemetry. To configure the desired TeleDongle frequency, select
1942 the monitor flight tab, then use the frequency selector and
1943 close the window before performing other desired radio operations.
1946 The flight computers only enable radio commanding in 'idle' mode.
1947 TeleMetrum and TeleMega use the accelerometer to detect which orientation they
1948 start up in, so make sure you have the flight computer lying horizontally when you turn
1949 it on. Otherwise, it will start in 'pad' mode ready for
1950 flight, and will not be listening for command packets from TeleDongle.
1953 TeleMini listens for a command packet for five seconds after
1954 first being turned on, if it doesn't hear anything, it enters
1955 'pad' mode, ready for flight and will no longer listen for
1956 command packets. The easiest way to connect to TeleMini is to
1957 initiate the command and select the TeleDongle device. At this
1958 point, the TeleDongle will be attempting to communicate with
1959 the TeleMini. Now turn TeleMini on, and it should immediately
1960 start communicating with the TeleDongle and the desired
1961 operation can be performed.
1964 You can monitor the operation of the radio link by watching the
1965 lights on the devices. The red LED will flash each time a packet
1966 is transmitted, while the green LED will light up on TeleDongle when
1967 it is waiting to receive a packet from the altimeter.
1971 <title>Ground Testing </title>
1973 An important aspect of preparing a rocket using electronic deployment
1974 for flight is ground testing the recovery system. Thanks
1975 to the bi-directional radio link central to the Altus Metrum system,
1976 this can be accomplished in a TeleMega, TeleMetrum or TeleMini equipped rocket
1977 with less work than you may be accustomed to with other systems. It
1981 Just prep the rocket for flight, then power up the altimeter
1982 in “idle” mode (placing air-frame horizontal for TeleMetrum or TeleMega, or
1983 selecting the Configure Altimeter tab for TeleMini). This will cause
1984 the firmware to go into “idle” mode, in which the normal flight
1985 state machine is disabled and charges will not fire without
1986 manual command. You can now command the altimeter to fire the apogee
1987 or main charges from a safe distance using your computer and
1988 TeleDongle and the Fire Igniter tab to complete ejection testing.
1992 <title>Radio Link </title>
1994 Our flight computers all incorporate an RF transceiver, but
1995 it's not a full duplex system... each end can only be transmitting or
1996 receiving at any given moment. So we had to decide how to manage the
2000 By design, the altimeter firmware listens for the radio link when
2001 it's in “idle mode”, which
2002 allows us to use the radio link to configure the rocket, do things like
2003 ejection tests, and extract data after a flight without having to
2004 crack open the air-frame. However, when the board is in “flight
2005 mode”, the altimeter only
2006 transmits and doesn't listen at all. That's because we want to put
2007 ultimate priority on event detection and getting telemetry out of
2009 the radio in case the rocket crashes and we aren't able to extract
2013 We don't generally use a 'normal packet radio' mode like APRS
2014 because they're just too inefficient. The GFSK modulation we
2015 use is FSK with the base-band pulses passed through a Gaussian
2016 filter before they go into the modulator to limit the
2017 transmitted bandwidth. When combined with forward error
2018 correction and interleaving, this allows us to have a very
2019 robust 19.2 kilobit data link with only 10-40 milliwatts of
2020 transmit power, a whip antenna in the rocket, and a hand-held
2021 Yagi on the ground. We've had flights to above 21k feet AGL
2022 with great reception, and calculations suggest we should be
2023 good to well over 40k feet AGL with a 5-element yagi on the
2024 ground with our 10mW units and over 100k feet AGL with the
2025 40mW devices. We hope to fly boards to higher altitudes over
2026 time, and would of course appreciate customer feedback on
2027 performance in higher altitude flights!
2033 TeleMetrum v2.0 and TeleMega can send APRS if desired, and the
2034 interval between APRS packets can be configured. As each APRS
2035 packet takes a full second to transmit, we recommend an
2036 interval of at least 5 seconds to avoid consuming too much
2037 battery power or radio channel bandwidth. You can configure
2038 the APRS interval using AltosUI; that process is described in
2039 the Configure Altimeter section of the AltosUI chapter.
2042 AltOS uses the APRS compressed position report data format,
2043 which provides for higher position precision and shorter
2044 packets than the original APRS format. It also includes
2045 altitude data, which is invaluable when tracking rockets. We
2046 haven't found a receiver which doesn't handle compressed
2047 positions, but it's just possible that you have one, so if you
2048 have an older device that can receive the raw packets but
2049 isn't displaying position information, it's possible that this
2053 The APRS packet format includes a comment field that can have
2054 arbitrary text in it. AltOS uses this to send status
2055 information about the flight computer. It sends four fields as
2056 shown in the following table.
2059 <title>Altus Metrum APRS Comments</title>
2060 <?dbfo keep-together="always"?>
2061 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
2062 <colspec align='center' colwidth='*' colname='Field'/>
2063 <colspec align='center' colwidth='*' colname='Example'/>
2064 <colspec align='center' colwidth='4*' colname='Description'/>
2067 <entry align='center'>Field</entry>
2068 <entry align='center'>Example</entry>
2069 <entry align='center'>Description</entry>
2076 <entry>GPS Status U for unlocked, L for locked</entry>
2081 <entry>Number of Satellites in View</entry>
2086 <entry>Altimeter Battery Voltage</entry>
2091 <entry>Apogee Igniter Voltage</entry>
2096 <entry>Main Igniter Voltage</entry>
2102 Here's an example of an APRS comment showing GPS lock with 6
2103 satellites in view, a primary battery at 4.0V, and
2104 apogee and main igniters both at 3.7V.
2110 Make sure your primary battery is above 3.8V, any connected
2111 igniters are above 3.5V and GPS is locked with at least 5 or 6
2112 satellites in view before flying. If GPS is switching between
2113 L and U regularly, then it doesn't have a good lock and you
2114 should wait until it becomes stable.
2117 If the GPS receiver loses lock, the APRS data transmitted will
2118 contain the last position for which GPS lock was
2119 available. You can tell that this has happened by noticing
2120 that the GPS status character switches from 'L' to 'U'. Before
2121 GPS has locked, APRS will transmit zero for latitude,
2122 longitude and altitude.
2126 <title>Configurable Parameters</title>
2128 Configuring an Altus Metrum altimeter for flight is very
2129 simple. Even on our baro-only TeleMini and EasyMini boards,
2130 the use of a Kalman filter means there is no need to set a
2131 “mach delay”. The few configurable parameters can all be set
2132 using AltosUI over USB or or radio link via TeleDongle. Read
2133 the Configure Altimeter section in the AltosUI chapter below
2134 for more information.
2137 <title>Radio Frequency</title>
2139 Altus Metrum boards support radio frequencies in the 70cm
2140 band. By default, the configuration interface provides a
2141 list of 10 “standard” frequencies in 100kHz channels starting at
2142 434.550MHz. However, the firmware supports use of
2143 any 50kHz multiple within the 70cm band. At any given
2144 launch, we highly recommend coordinating when and by whom each
2145 frequency will be used to avoid interference. And of course, both
2146 altimeter and TeleDongle must be configured to the same
2147 frequency to successfully communicate with each other.
2151 <title>Callsign</title>
2153 This sets the callsign used for telemetry, APRS and the
2154 packet link. For telemetry and APRS, this is used to
2155 identify the device. For the packet link, the callsign must
2156 match that configured in AltosUI or the link will not
2157 work. This is to prevent accidental configuration of another
2158 Altus Metrum flight computer operating on the same frequency nearby.
2162 <title>Telemetry/RDF/APRS Enable</title>
2164 You can completely disable the radio while in flight, if
2165 necessary. This doesn't disable the packet link in idle
2170 <title>APRS Interval</title>
2172 This selects how often APRS packets are transmitted. Set
2173 this to zero to disable APRS without also disabling the
2174 regular telemetry and RDF transmissions. As APRS takes a
2175 full second to transmit a single position report, we
2176 recommend sending packets no more than once every 5 seconds.
2180 <title>Apogee Delay</title>
2182 Apogee delay is the number of seconds after the altimeter detects flight
2183 apogee that the drogue charge should be fired. In most cases, this
2184 should be left at the default of 0. However, if you are flying
2185 redundant electronics such as for an L3 certification, you may wish
2186 to set one of your altimeters to a positive delay so that both
2187 primary and backup pyrotechnic charges do not fire simultaneously.
2190 The Altus Metrum apogee detection algorithm fires exactly at
2191 apogee. If you are also flying an altimeter like the
2192 PerfectFlite MAWD, which only supports selecting 0 or 1
2193 seconds of apogee delay, you may wish to set the MAWD to 0
2194 seconds delay and set the TeleMetrum to fire your backup 2
2195 or 3 seconds later to avoid any chance of both charges
2196 firing simultaneously. We've flown several air-frames this
2197 way quite happily, including Keith's successful L3 cert.
2201 <title>Apogee Lockout</title>
2203 Apogee lockout is the number of seconds after boost where
2204 the flight computer will not fire the apogee charge, even if
2205 the rocket appears to be at apogee. This is often called
2206 'Mach Delay', as it is intended to prevent a flight computer
2207 from unintentionally firing apogee charges due to the pressure
2208 spike that occurrs across a mach transition. Altus Metrum
2209 flight computers include a Kalman filter which is not fooled
2210 by this sharp pressure increase, and so this setting should
2211 be left at the default value of zero to disable it.
2215 <title>Main Deployment Altitude</title>
2217 By default, the altimeter will fire the main deployment charge at an
2218 elevation of 250 meters (about 820 feet) above ground. We think this
2219 is a good elevation for most air-frames, but feel free to change this
2220 to suit. In particular, if you are flying two altimeters, you may
2222 deployment elevation for the backup altimeter to be something lower
2223 than the primary so that both pyrotechnic charges don't fire
2228 <title>Maximum Flight Log</title>
2230 Changing this value will set the maximum amount of flight
2231 log storage that an individual flight will use. The
2232 available storage is divided into as many flights of the
2233 specified size as can fit in the available space. You can
2234 download and erase individual flight logs. If you fill up
2235 the available storage, future flights will not get logged
2236 until you erase some of the stored ones.
2239 Even though our flight computers (except TeleMini v1.0) can store
2240 multiple flights, we strongly recommend downloading and saving
2241 flight data after each flight.
2245 <title>Ignite Mode</title>
2247 Instead of firing one charge at apogee and another charge at
2248 a fixed height above the ground, you can configure the
2249 altimeter to fire both at apogee or both during
2250 descent. This was added to support an airframe Bdale designed that
2251 had two altimeters, one in the fin can and one in the nose.
2254 Providing the ability to use both igniters for apogee or
2255 main allows some level of redundancy without needing two
2256 flight computers. In Redundant Apogee or Redundant Main
2257 mode, the two charges will be fired two seconds apart.
2261 <title>Pad Orientation</title>
2263 TeleMetrum and TeleMega measure acceleration along the axis
2264 of the board. Which way the board is oriented affects the
2265 sign of the acceleration value. Instead of trying to guess
2266 which way the board is mounted in the air frame, the
2267 altimeter must be explicitly configured for either Antenna
2268 Up or Antenna Down. The default, Antenna Up, expects the end
2269 of the board connected to the 70cm antenna to be nearest the
2270 nose of the rocket, with the end containing the screw
2271 terminals nearest the tail.
2275 <title>Configurable Pyro Channels</title>
2277 In addition to the usual Apogee and Main pyro channels,
2278 TeleMega has four additional channels that can be configured
2279 to activate when various flight conditions are
2280 satisfied. You can select as many conditions as necessary;
2281 all of them must be met in order to activate the
2282 channel. The conditions available are:
2287 Acceleration away from the ground. Select a value, and
2288 then choose whether acceleration should be above or
2289 below that value. Acceleration is positive upwards, so
2290 accelerating towards the ground would produce negative
2291 numbers. Acceleration during descent is noisy and
2292 inaccurate, so be careful when using it during these
2293 phases of the flight.
2298 Vertical speed. Select a value, and then choose whether
2299 vertical speed should be above or below that
2300 value. Speed is positive upwards, so moving towards the
2301 ground would produce negative numbers. Speed during
2302 descent is a bit noisy and so be careful when using it
2303 during these phases of the flight.
2308 Height. Select a value, and then choose whether the
2309 height above the launch pad should be above or below
2315 Orientation. TeleMega contains a 3-axis gyroscope and
2316 accelerometer which is used to measure the current
2317 angle. Note that this angle is not the change in angle
2318 from the launch pad, but rather absolute relative to
2319 gravity; the 3-axis accelerometer is used to compute the
2320 angle of the rocket on the launch pad and initialize the
2321 system. Because this value is computed by integrating
2322 rate gyros, it gets progressively less accurate as the
2323 flight goes on. It should have an accumulated error of
2324 less than 0.2°/second (after 10 seconds of flight, the
2325 error should be less than 2°).
2328 The usual use of the orientation configuration is to
2329 ensure that the rocket is traveling mostly upwards when
2330 deciding whether to ignite air starts or additional
2331 stages. For that, choose a reasonable maximum angle
2332 (like 20°) and set the motor igniter to require an angle
2333 of less than that value.
2338 Flight Time. Time since boost was detected. Select a
2339 value and choose whether to activate the pyro channel
2340 before or after that amount of time.
2345 Ascending. A simple test saying whether the rocket is
2346 going up or not. This is exactly equivalent to testing
2347 whether the speed is > 0.
2352 Descending. A simple test saying whether the rocket is
2353 going down or not. This is exactly equivalent to testing
2354 whether the speed is < 0.
2359 After Motor. The flight software counts each time the
2360 rocket starts accelerating (presumably due to a motor or
2361 motors igniting). Use this value to count ignitions for
2362 multi-staged or multi-airstart launches.
2367 Delay. This value doesn't perform any checks, instead it
2368 inserts a delay between the time when the other
2369 parameters become true and when the pyro channel is
2375 Flight State. The flight software tracks the flight
2376 through a sequence of states:
2380 Boost. The motor has lit and the rocket is
2381 accelerating upwards.
2386 Fast. The motor has burned out and the rocket is
2387 decelerating, but it is going faster than 200m/s.
2392 Coast. The rocket is still moving upwards and
2393 decelerating, but the speed is less than 200m/s.
2398 Drogue. The rocket has reached apogee and is heading
2399 back down, but is above the configured Main
2405 Main. The rocket is still descending, and is below
2411 Landed. The rocket is no longer moving.
2417 You can select a state to limit when the pyro channel
2418 may activate; note that the check is based on when the
2419 rocket transitions <emphasis>into</emphasis> the state, and so checking for
2420 “greater than Boost” means that the rocket is currently
2421 in boost or some later state.
2424 When a motor burns out, the rocket enters either Fast or
2425 Coast state (depending on how fast it is moving). If the
2426 computer detects upwards acceleration again, it will
2427 move back to Boost state.
2436 <title>AltosUI</title>
2440 <imagedata fileref="altosui.png" width="4.6in"/>
2445 The AltosUI program provides a graphical user interface for
2446 interacting with the Altus Metrum product family. AltosUI can
2447 monitor telemetry data, configure devices and many other
2448 tasks. The primary interface window provides a selection of
2449 buttons, one for each major activity in the system. This chapter
2450 is split into sections, each of which documents one of the tasks
2451 provided from the top-level toolbar.
2454 <title>Monitor Flight</title>
2455 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
2457 Selecting this item brings up a dialog box listing all of the
2458 connected TeleDongle devices. When you choose one of these,
2459 AltosUI will create a window to display telemetry data as
2460 received by the selected TeleDongle device.
2465 <imagedata fileref="device-selection.png" width="3.1in"/>
2470 All telemetry data received are automatically recorded in
2471 suitable log files. The name of the files includes the current
2472 date and rocket serial and flight numbers.
2475 The radio frequency being monitored by the TeleDongle device is
2476 displayed at the top of the window. You can configure the
2477 frequency by clicking on the frequency box and selecting the desired
2478 frequency. AltosUI remembers the last frequency selected for each
2479 TeleDongle and selects that automatically the next time you use
2483 Below the TeleDongle frequency selector, the window contains a few
2484 significant pieces of information about the altimeter providing
2485 the telemetry data stream:
2489 <para>The configured call-sign</para>
2492 <para>The device serial number</para>
2495 <para>The flight number. Each altimeter remembers how many
2501 The rocket flight state. Each flight passes through several
2502 states including Pad, Boost, Fast, Coast, Drogue, Main and
2508 The Received Signal Strength Indicator value. This lets
2509 you know how strong a signal TeleDongle is receiving. The
2510 radio inside TeleDongle operates down to about -99dBm;
2511 weaker signals may not be receivable. The packet link uses
2512 error detection and correction techniques which prevent
2513 incorrect data from being reported.
2518 The age of the displayed data, in seconds since the last
2519 successfully received telemetry packet. In normal operation
2520 this will stay in the low single digits. If the number starts
2521 counting up, then you are no longer receiving data over the radio
2522 link from the flight computer.
2527 Finally, the largest portion of the window contains a set of
2528 tabs, each of which contain some information about the rocket.
2529 They're arranged in 'flight order' so that as the flight
2530 progresses, the selected tab automatically switches to display
2531 data relevant to the current state of the flight. You can select
2532 other tabs at any time. The final 'table' tab displays all of
2533 the raw telemetry values in one place in a spreadsheet-like format.
2536 <title>Launch Pad</title>
2540 <imagedata fileref="launch-pad.png" width="5.5in"/>
2545 The 'Launch Pad' tab shows information used to decide when the
2546 rocket is ready for flight. The first elements include red/green
2547 indicators, if any of these is red, you'll want to evaluate
2548 whether the rocket is ready to launch:
2551 <term>Battery Voltage</term>
2554 This indicates whether the Li-Po battery powering the
2555 flight computer has sufficient charge to last for
2556 the duration of the flight. A value of more than
2557 3.8V is required for a 'GO' status.
2562 <term>Apogee Igniter Voltage</term>
2565 This indicates whether the apogee
2566 igniter has continuity. If the igniter has a low
2567 resistance, then the voltage measured here will be close
2568 to the Li-Po battery voltage. A value greater than 3.2V is
2569 required for a 'GO' status.
2574 <term>Main Igniter Voltage</term>
2577 This indicates whether the main
2578 igniter has continuity. If the igniter has a low
2579 resistance, then the voltage measured here will be close
2580 to the Li-Po battery voltage. A value greater than 3.2V is
2581 required for a 'GO' status.
2586 <term>On-board Data Logging</term>
2589 This indicates whether there is
2590 space remaining on-board to store flight data for the
2591 upcoming flight. If you've downloaded data, but failed
2592 to erase flights, there may not be any space
2593 left. Most of our flight computers can store multiple
2594 flights, depending on the configured maximum flight log
2595 size. TeleMini v1.0 stores only a single flight, so it
2597 downloaded and erased after each flight to capture
2598 data. This only affects on-board flight logging; the
2599 altimeter will still transmit telemetry and fire
2600 ejection charges at the proper times even if the flight
2601 data storage is full.
2606 <term>GPS Locked</term>
2609 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
2610 currently able to compute position information. GPS requires
2611 at least 4 satellites to compute an accurate position.
2616 <term>GPS Ready</term>
2619 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
2620 10 consecutive positions without losing lock. This ensures
2621 that the GPS receiver has reliable reception from the
2629 The Launchpad tab also shows the computed launch pad position
2630 and altitude, averaging many reported positions to improve the
2631 accuracy of the fix.
2635 <title>Ascent</title>
2639 <imagedata fileref="ascent.png" width="5.5in"/>
2644 This tab is shown during Boost, Fast and Coast
2645 phases. The information displayed here helps monitor the
2646 rocket as it heads towards apogee.
2649 The height, speed, acceleration and tilt are shown along
2650 with the maximum values for each of them. This allows you to
2651 quickly answer the most commonly asked questions you'll hear
2655 The current latitude and longitude reported by the GPS are
2656 also shown. Note that under high acceleration, these values
2657 may not get updated as the GPS receiver loses position
2658 fix. Once the rocket starts coasting, the receiver should
2659 start reporting position again.
2662 Finally, the current igniter voltages are reported as in the
2663 Launch Pad tab. This can help diagnose deployment failures
2664 caused by wiring which comes loose under high acceleration.
2668 <title>Descent</title>
2672 <imagedata fileref="descent.png" width="5.5in"/>
2677 Once the rocket has reached apogee and (we hope) activated the
2678 apogee charge, attention switches to tracking the rocket on
2679 the way back to the ground, and for dual-deploy flights,
2680 waiting for the main charge to fire.
2683 To monitor whether the apogee charge operated correctly, the
2684 current descent rate is reported along with the current
2685 height. Good descent rates vary based on the choice of recovery
2686 components, but generally range from 15-30m/s on drogue and should
2687 be below 10m/s when under the main parachute in a dual-deploy flight.
2690 With GPS-equipped flight computers, you can locate the rocket in the
2691 sky using the elevation and bearing information to figure
2692 out where to look. Elevation is in degrees above the
2693 horizon. Bearing is reported in degrees relative to true
2694 north. Range can help figure out how big the rocket will
2695 appear. Ground Distance shows how far it is to a point
2696 directly under the rocket and can help figure out where the
2697 rocket is likely to land. Note that all of these values are
2698 relative to the pad location. If the elevation is near 90°,
2699 the rocket is over the pad, not over you.
2702 Finally, the igniter voltages are reported in this tab as
2703 well, both to monitor the main charge as well as to see what
2704 the status of the apogee charge is. Note that some commercial
2705 e-matches are designed to retain continuity even after being
2706 fired, and will continue to show as green or return from red to
2711 <title>Landed</title>
2715 <imagedata fileref="landed.png" width="5.5in"/>
2720 Once the rocket is on the ground, attention switches to
2721 recovery. While the radio signal is often lost once the
2722 rocket is on the ground, the last reported GPS position is
2723 generally within a short distance of the actual landing location.
2726 The last reported GPS position is reported both by
2727 latitude and longitude as well as a bearing and distance from
2728 the launch pad. The distance should give you a good idea of
2729 whether to walk or hitch a ride. Take the reported
2730 latitude and longitude and enter them into your hand-held GPS
2731 unit and have that compute a track to the landing location.
2734 Our flight computers will continue to transmit RDF
2735 tones after landing, allowing you to locate the rocket by
2736 following the radio signal if necessary. You may need to get
2737 away from the clutter of the flight line, or even get up on
2738 a hill (or your neighbor's RV roof) to receive the RDF signal.
2741 The maximum height, speed and acceleration reported
2742 during the flight are displayed for your admiring observers.
2743 The accuracy of these immediate values depends on the quality
2744 of your radio link and how many packets were received.
2745 Recovering the on-board data after flight may yield
2746 more precise results.
2749 To get more detailed information about the flight, you can
2750 click on the 'Graph Flight' button which will bring up a
2751 graph window for the current flight.
2755 <title>Table</title>
2759 <imagedata fileref="table.png" width="5.5in"/>
2764 The table view shows all of the data available from the
2765 flight computer. Probably the most useful data on
2766 this tab is the detailed GPS information, which includes
2767 horizontal dilution of precision information, and
2768 information about the signal being received from the satellites.
2772 <title>Site Map</title>
2776 <imagedata fileref="site-map.png" width="5.5in"/>
2781 When the TeleMetrum has a GPS fix, the Site Map tab will map
2782 the rocket's position to make it easier for you to locate the
2783 rocket, both while it is in the air, and when it has landed. The
2784 rocket's state is indicated by color: white for pad, red for
2785 boost, pink for fast, yellow for coast, light blue for drogue,
2786 dark blue for main, and black for landed.
2789 The map's default scale is approximately 3m (10ft) per pixel. The map
2790 can be dragged using the left mouse button. The map will attempt
2791 to keep the rocket roughly centered while data is being received.
2794 You can adjust the style of map and the zoom level with
2795 buttons on the right side of the map window. You can draw a
2796 line on the map by moving the mouse over the map with a
2797 button other than the left one pressed, or by pressing the
2798 left button while also holding down the shift key. The
2799 length of the line in real-world units will be shown at the
2803 Images are fetched automatically via the Google Maps Static API,
2804 and cached on disk for reuse. If map images cannot be downloaded,
2805 the rocket's path will be traced on a dark gray background
2809 You can pre-load images for your favorite launch sites
2810 before you leave home; check out the 'Preload Maps' section below.
2814 <title>Ignitor</title>
2818 <imagedata fileref="ignitor.png" width="5.5in"/>
2823 TeleMega includes four additional programmable pyro
2824 channels. The Ignitor tab shows whether each of them has
2825 continuity. If an ignitor has a low resistance, then the
2826 voltage measured here will be close to the pyro battery
2827 voltage. A value greater than 3.2V is required for a 'GO'
2833 <title>Save Flight Data</title>
2835 The altimeter records flight data to its internal flash memory.
2836 TeleMetrum data is recorded at a much higher rate than the telemetry
2837 system can handle, and is not subject to radio drop-outs. As
2838 such, it provides a more complete and precise record of the
2839 flight. The 'Save Flight Data' button allows you to read the
2840 flash memory and write it to disk.
2843 Clicking on the 'Save Flight Data' button brings up a list of
2844 connected flight computers and TeleDongle devices. If you select a
2845 flight computer, the flight data will be downloaded from that
2846 device directly. If you select a TeleDongle device, flight data
2847 will be downloaded from a flight computer over radio link via the
2848 specified TeleDongle. See the chapter on Controlling An Altimeter
2849 Over The Radio Link for more information.
2852 After the device has been selected, a dialog showing the
2853 flight data saved in the device will be shown allowing you to
2854 select which flights to download and which to delete. With
2855 version 0.9 or newer firmware, you must erase flights in order
2856 for the space they consume to be reused by another
2857 flight. This prevents accidentally losing flight data
2858 if you neglect to download data before flying again. Note that
2859 if there is no more space available in the device, then no
2860 data will be recorded during the next flight.
2863 The file name for each flight log is computed automatically
2864 from the recorded flight date, altimeter serial number and
2865 flight number information.
2869 <title>Replay Flight</title>
2871 Select this button and you are prompted to select a flight
2872 record file, either a .telem file recording telemetry data or a
2873 .eeprom file containing flight data saved from the altimeter
2877 Once a flight record is selected, the flight monitor interface
2878 is displayed and the flight is re-enacted in real time. Check
2879 the Monitor Flight chapter above to learn how this window operates.
2883 <title>Graph Data</title>
2885 Select this button and you are prompted to select a flight
2886 record file, either a .telem file recording telemetry data or a
2887 .eeprom file containing flight data saved from
2891 Note that telemetry files will generally produce poor graphs
2892 due to the lower sampling rate and missed telemetry packets.
2893 Use saved flight data in .eeprom files for graphing where possible.
2896 Once a flight record is selected, a window with multiple tabs is
2900 <title>Flight Graph</title>
2904 <imagedata fileref="graph.png" width="6in" scalefit="1"/>
2909 By default, the graph contains acceleration (blue),
2910 velocity (green) and altitude (red).
2913 The graph can be zoomed into a particular area by clicking and
2914 dragging down and to the right. Once zoomed, the graph can be
2915 reset by clicking and dragging up and to the left. Holding down
2916 control and clicking and dragging allows the graph to be panned.
2917 The right mouse button causes a pop-up menu to be displayed, giving
2918 you the option save or print the plot.
2922 <title>Configure Graph</title>
2926 <imagedata fileref="graph-configure.png" width="6in" scalefit="1"/>
2931 This selects which graph elements to show, and, at the
2932 very bottom, lets you switch between metric and
2937 <title>Flight Statistics</title>
2941 <imagedata fileref="graph-stats.png" width="6in" scalefit="1"/>
2946 Shows overall data computed from the flight.
2954 <imagedata fileref="graph-map.png" width="6in" scalefit="1"/>
2959 Shows a satellite image of the flight area overlaid
2960 with the path of the flight. The red concentric
2961 circles mark the launch pad, the black concentric
2962 circles mark the landing location.
2967 <title>Export Data</title>
2969 This tool takes the raw data files and makes them available for
2970 external analysis. When you select this button, you are prompted to
2971 select a flight data file, which can be either a .eeprom or .telem.
2972 The .eeprom files contain higher resolution and more continuous data,
2973 while .telem files contain receiver signal strength information.
2974 Next, a second dialog appears which is used to select
2975 where to write the resulting file. It has a selector to choose
2976 between CSV and KML file formats.
2979 <title>Comma Separated Value Format</title>
2981 This is a text file containing the data in a form suitable for
2982 import into a spreadsheet or other external data analysis
2983 tool. The first few lines of the file contain the version and
2984 configuration information from the altimeter, then
2985 there is a single header line which labels all of the
2986 fields. All of these lines start with a '#' character which
2987 many tools can be configured to skip over.
2990 The remaining lines of the file contain the data, with each
2991 field separated by a comma and at least one space. All of
2992 the sensor values are converted to standard units, with the
2993 barometric data reported in both pressure, altitude and
2994 height above pad units.
2998 <title>Keyhole Markup Language (for Google Earth)</title>
3000 This is the format used by Google Earth to provide an overlay
3001 within that application. With this, you can use Google Earth to
3002 see the whole flight path in 3D.
3007 <title>Configure Altimeter</title>
3011 <imagedata fileref="configure-altimeter.png" width="3.6in" scalefit="1"/>
3016 Select this button and then select either an altimeter or
3017 TeleDongle Device from the list provided. Selecting a TeleDongle
3018 device will use the radio link to configure a remote altimeter.
3021 The first few lines of the dialog provide information about the
3022 connected device, including the product name,
3023 software version and hardware serial number. Below that are the
3024 individual configuration entries.
3027 At the bottom of the dialog, there are four buttons:
3034 This writes any changes to the
3035 configuration parameter block in flash memory. If you don't
3036 press this button, any changes you make will be lost.
3044 This resets the dialog to the most recently saved values,
3045 erasing any changes you have made.
3053 This reboots the device. Use this to
3054 switch from idle to pad mode by rebooting once the rocket is
3055 oriented for flight, or to confirm changes you think you saved
3064 This closes the dialog. Any unsaved changes will be
3071 The rest of the dialog contains the parameters to be configured.
3074 <title>Main Deploy Altitude</title>
3076 This sets the altitude (above the recorded pad altitude) at
3077 which the 'main' igniter will fire. The drop-down menu shows
3078 some common values, but you can edit the text directly and
3079 choose whatever you like. If the apogee charge fires below
3080 this altitude, then the main charge will fire two seconds
3081 after the apogee charge fires.
3085 <title>Apogee Delay</title>
3087 When flying redundant electronics, it's often important to
3088 ensure that multiple apogee charges don't fire at precisely
3089 the same time, as that can over pressurize the apogee deployment
3090 bay and cause a structural failure of the air-frame. The Apogee
3091 Delay parameter tells the flight computer to fire the apogee
3092 charge a certain number of seconds after apogee has been
3097 <title>Apogee Lockoug</title>
3099 Apogee lockout is the number of seconds after boost where
3100 the flight computer will not fire the apogee charge, even if
3101 the rocket appears to be at apogee. This is often called
3102 'Mach Delay', as it is intended to prevent a flight computer
3103 from unintentionally firing apogee charges due to the pressure
3104 spike that occurrs across a mach transition. Altus Metrum
3105 flight computers include a Kalman filter which is not fooled
3106 by this sharp pressure increase, and so this setting should
3107 be left at the default value of zero to disable it.
3111 <title>Frequency</title>
3113 This configures which of the frequencies to use for both
3114 telemetry and packet command mode. Note that if you set this
3115 value via packet command mode, the TeleDongle frequency will
3116 also be automatically reconfigured to match so that
3117 communication will continue afterwards.
3121 <title>RF Calibration</title>
3123 The radios in every Altus Metrum device are calibrated at the
3124 factory to ensure that they transmit and receive on the
3125 specified frequency. If you need to you can adjust the calibration
3126 by changing this value. Do not do this without understanding what
3127 the value means, read the appendix on calibration and/or the source
3128 code for more information. To change a TeleDongle's calibration,
3129 you must reprogram the unit completely.
3133 <title>Telemetry/RDF/APRS Enable</title>
3135 Enables the radio for transmission during flight. When
3136 disabled, the radio will not transmit anything during flight
3141 <title>APRS Interval</title>
3143 How often to transmit GPS information via APRS (in
3144 seconds). When set to zero, APRS transmission is
3145 disabled. This option is available on TeleMetrum v2 and
3146 TeleMega boards. TeleMetrum v1 boards cannot transmit APRS
3147 packets. Note that a single APRS packet takes nearly a full
3148 second to transmit, so enabling this option will prevent
3149 sending any other telemetry during that time.
3153 <title>Callsign</title>
3155 This sets the call sign included in each telemetry packet. Set this
3156 as needed to conform to your local radio regulations.
3160 <title>Maximum Flight Log Size</title>
3162 This sets the space (in kilobytes) allocated for each flight
3163 log. The available space will be divided into chunks of this
3164 size. A smaller value will allow more flights to be stored,
3165 a larger value will record data from longer flights.
3169 <title>Ignitor Firing Mode</title>
3171 This configuration parameter allows the two standard ignitor
3172 channels (Apogee and Main) to be used in different
3177 <term>Dual Deploy</term>
3180 This is the usual mode of operation; the
3181 'apogee' channel is fired at apogee and the 'main'
3182 channel at the height above ground specified by the
3183 'Main Deploy Altitude' during descent.
3188 <term>Redundant Apogee</term>
3191 This fires both channels at
3192 apogee, the 'apogee' channel first followed after a two second
3193 delay by the 'main' channel.
3198 <term>Redundant Main</term>
3201 This fires both channels at the
3202 height above ground specified by the Main Deploy
3203 Altitude setting during descent. The 'apogee'
3204 channel is fired first, followed after a two second
3205 delay by the 'main' channel.
3212 <title>Pad Orientation</title>
3214 Because they include accelerometers, TeleMetrum and
3215 TeleMega are sensitive to the orientation of the board. By
3216 default, they expect the antenna end to point forward. This
3217 parameter allows that default to be changed, permitting the
3218 board to be mounted with the antenna pointing aft instead.
3222 <term>Antenna Up</term>
3225 In this mode, the antenna end of the
3226 flight computer must point forward, in line with the
3227 expected flight path.
3232 <term>Antenna Down</term>
3235 In this mode, the antenna end of the
3236 flight computer must point aft, in line with the
3237 expected flight path.
3244 <title>Beeper Frequency</title>
3246 The beeper on all Altus Metrum flight computers works best
3247 at 4000Hz, however if you have more than one flight computer
3248 in a single airframe, having all of them sound at the same
3249 frequency can be confusing. This parameter lets you adjust
3250 the base beeper frequency value.
3254 <title>Configure Pyro Channels</title>
3258 <imagedata fileref="configure-pyro.png" width="6in" scalefit="1"/>
3263 This opens a separate window to configure the additional
3264 pyro channels available on TeleMega. One column is
3265 presented for each channel. Each row represents a single
3266 parameter, if enabled the parameter must meet the specified
3267 test for the pyro channel to be fired. See the Pyro Channels
3268 section in the System Operation chapter above for a
3269 description of these parameters.
3272 Select conditions and set the related value; the pyro
3273 channel will be activated when <emphasis>all</emphasis> of the
3274 conditions are met. Each pyro channel has a separate set of
3275 configuration values, so you can use different values for
3276 the same condition with different channels.
3279 At the bottom of the window, the 'Pyro Firing Time'
3280 configuration sets the length of time (in seconds) which
3281 each of these pyro channels will fire for.
3284 Once you have selected the appropriate configuration for all
3285 of the necessary pyro channels, you can save the pyro
3286 configuration along with the rest of the flight computer
3287 configuration by pressing the 'Save' button in the main
3288 Configure Flight Computer window.
3293 <title>Configure AltosUI</title>
3297 <imagedata fileref="configure-altosui.png" width="2.4in" scalefit="1"/>
3302 This button presents a dialog so that you can configure the AltosUI global settings.
3305 <title>Voice Settings</title>
3307 AltosUI provides voice announcements during flight so that you
3308 can keep your eyes on the sky and still get information about
3309 the current flight status. However, sometimes you don't want
3316 <para>Turns all voice announcements on and off</para>
3320 <term>Test Voice</term>
3323 Plays a short message allowing you to verify
3324 that the audio system is working and the volume settings
3332 <title>Log Directory</title>
3334 AltosUI logs all telemetry data and saves all TeleMetrum flash
3335 data to this directory. This directory is also used as the
3336 staring point when selecting data files for display or export.
3339 Click on the directory name to bring up a directory choosing
3340 dialog, select a new directory and click 'Select Directory' to
3341 change where AltosUI reads and writes data files.
3345 <title>Callsign</title>
3347 This value is transmitted in each command packet sent from
3348 TeleDongle and received from an altimeter. It is not used in
3349 telemetry mode, as the callsign configured in the altimeter board
3350 is included in all telemetry packets. Configure this
3351 with the AltosUI operators call sign as needed to comply with
3352 your local radio regulations.
3355 Note that to successfully command a flight computer over the radio
3356 (to configure the altimeter, monitor idle, or fire pyro charges),
3357 the callsign configured here must exactly match the callsign
3358 configured in the flight computer. This matching is case
3363 <title>Imperial Units</title>
3365 This switches between metric units (meters) and imperial
3366 units (feet and miles). This affects the display of values
3367 use during flight monitoring, configuration, data graphing
3368 and all of the voice announcements. It does not change the
3369 units used when exporting to CSV files, those are always
3370 produced in metric units.
3374 <title>Font Size</title>
3376 Selects the set of fonts used in the flight monitor
3377 window. Choose between the small, medium and large sets.
3381 <title>Serial Debug</title>
3383 This causes all communication with a connected device to be
3384 dumped to the console from which AltosUI was started. If
3385 you've started it from an icon or menu entry, the output
3386 will simply be discarded. This mode can be useful to debug
3387 various serial communication issues.
3391 <title>Manage Frequencies</title>
3393 This brings up a dialog where you can configure the set of
3394 frequencies shown in the various frequency menus. You can
3395 add as many as you like, or even reconfigure the default
3396 set. Changing this list does not affect the frequency
3397 settings of any devices, it only changes the set of
3398 frequencies shown in the menus.
3403 <title>Configure Groundstation</title>
3407 <imagedata fileref="configure-groundstation.png" width="3.1in" scalefit="1"/>
3412 Select this button and then select a TeleDongle Device from the list provided.
3415 The first few lines of the dialog provide information about the
3416 connected device, including the product name,
3417 software version and hardware serial number. Below that are the
3418 individual configuration entries.
3421 Note that the TeleDongle itself doesn't save any configuration
3422 data, the settings here are recorded on the local machine in
3423 the Java preferences database. Moving the TeleDongle to
3424 another machine, or using a different user account on the same
3425 machine will cause settings made here to have no effect.
3428 At the bottom of the dialog, there are three buttons:
3435 This writes any changes to the
3436 local Java preferences file. If you don't
3437 press this button, any changes you make will be lost.
3445 This resets the dialog to the most recently saved values,
3446 erasing any changes you have made.
3454 This closes the dialog. Any unsaved changes will be
3461 The rest of the dialog contains the parameters to be configured.
3464 <title>Frequency</title>
3466 This configures the frequency to use for both telemetry and
3467 packet command mode. Set this before starting any operation
3468 involving packet command mode so that it will use the right
3469 frequency. Telemetry monitoring mode also provides a menu to
3470 change the frequency, and that menu also sets the same Java
3471 preference value used here.
3475 <title>Radio Calibration</title>
3477 The radios in every Altus Metrum device are calibrated at the
3478 factory to ensure that they transmit and receive on the
3479 specified frequency. To change a TeleDongle's calibration,
3480 you must reprogram the unit completely, so this entry simply
3481 shows the current value and doesn't allow any changes.
3486 <title>Flash Image</title>
3488 This reprograms Altus Metrum devices with new
3489 firmware. TeleMetrum v1.x, TeleDongle, TeleMini and TeleBT are
3490 all reprogrammed by using another similar unit as a
3491 programming dongle (pair programming). TeleMega, TeleMetrum v2
3492 and EasyMini are all programmed directly over their USB ports
3493 (self programming). Please read the directions for flashing
3494 devices in the Updating Device Firmware chapter below.
3498 <title>Fire Igniter</title>
3502 <imagedata fileref="fire-igniter.png" width="1.2in" scalefit="1"/>
3507 This activates the igniter circuits in the flight computer to help
3508 test recovery systems deployment. Because this command can operate
3509 over the Packet Command Link, you can prepare the rocket as
3510 for flight and then test the recovery system without needing
3511 to snake wires inside the air-frame.
3514 Selecting the 'Fire Igniter' button brings up the usual device
3515 selection dialog. Pick the desired device. This brings up another
3516 window which shows the current continuity test status for all
3517 of the pyro channels.
3520 Next, select the desired igniter to fire. This will enable the
3524 Select the 'Arm' button. This enables the 'Fire' button. The
3525 word 'Arm' is replaced by a countdown timer indicating that
3526 you have 10 seconds to press the 'Fire' button or the system
3527 will deactivate, at which point you start over again at
3528 selecting the desired igniter.
3532 <title>Scan Channels</title>
3536 <imagedata fileref="scan-channels.png" width="3.2in" scalefit="1"/>
3541 This listens for telemetry packets on all of the configured
3542 frequencies, displaying information about each device it
3543 receives a packet from. You can select which of the three
3544 telemetry formats should be tried; by default, it only listens
3545 for the standard telemetry packets used in v1.0 and later
3550 <title>Load Maps</title>
3554 <imagedata fileref="load-maps.png" width="5.2in" scalefit="1"/>
3559 Before heading out to a new launch site, you can use this to
3560 load satellite images in case you don't have internet
3561 connectivity at the site. This loads a fairly large area
3562 around the launch site, which should cover any flight you're likely to make.
3565 There's a drop-down menu of launch sites we know about; if
3566 your favorites aren't there, please let us know the lat/lon
3567 and name of the site. The contents of this list are actually
3568 downloaded from our server at run-time, so as new sites are sent
3569 in, they'll get automatically added to this list.
3570 If the launch site isn't in the list, you can manually enter the lat/lon values
3573 There are four different kinds of maps you can view; you can
3574 select which to download by selecting as many as you like from
3575 the available types:
3581 A combination of satellite imagery and road data. This
3582 is the default view.
3587 <term>Satellite</term>
3590 Just the satellite imagery without any annotation.
3595 <term>Roadmap</term>
3598 Roads, political boundaries and a few geographic features.
3603 <term>Terrain</term>
3606 Contour intervals and shading that show hills and
3614 You can specify the range of zoom levels to download; smaller
3615 numbers show more area with less resolution. The default
3616 level, 0, shows about 3m/pixel. One zoom level change
3617 doubles or halves that number.
3620 The Tile Radius value sets how large an area around the center
3621 point to download. Each tile is 512x512 pixels, and the
3622 'radius' value specifies how many tiles away from the center
3623 will be downloaded. Specify a radius of 0 and you get only the
3624 center tile. A radius of 1 loads a 3x3 grid, centered on the
3628 Clicking the 'Load Map' button will fetch images from Google
3629 Maps; note that Google limits how many images you can fetch at
3630 once, so if you load more than one launch site, you may get
3631 some gray areas in the map which indicate that Google is tired
3632 of sending data to you. Try again later.
3636 <title>Monitor Idle</title>
3638 This brings up a dialog similar to the Monitor Flight UI,
3639 except it works with the altimeter in “idle” mode by sending
3640 query commands to discover the current state rather than
3641 listening for telemetry packets. Because this uses command
3642 mode, it needs to have the TeleDongle and flight computer
3643 callsigns match exactly. If you can receive telemetry, but
3644 cannot manage to run Monitor Idle, then it's very likely that
3645 your callsigns are different in some way.
3650 <title>AltosDroid</title>
3652 AltosDroid provides the same flight monitoring capabilities as
3653 AltosUI, but runs on Android devices and is designed to connect
3654 to a TeleBT receiver over Bluetooth™. AltosDroid monitors
3655 telemetry data, logging it to internal storage in the Android
3656 device, and presents that data in a UI the same way the 'Monitor
3657 Flight' window does in AltosUI.
3660 This manual will explain how to configure AltosDroid, connect
3661 to TeleBT, operate the flight monitoring interface and describe
3662 what the displayed data means.
3665 <title>Installing AltosDroid</title>
3667 AltosDroid is available from the Google Play store. To install
3668 it on your Android device, open the Google Play Store
3669 application and search for “altosdroid”. Make sure you don't
3670 have a space between “altos” and “droid” or you probably won't
3671 find what you want. That should bring you to the right page
3672 from which you can download and install the application.
3676 <title>Connecting to TeleBT</title>
3678 Press the Android 'Menu' button or soft-key to see the
3679 configuration options available. Select the 'Connect a device'
3680 option and then the 'Scan for devices' entry at the bottom to
3681 look for your TeleBT device. Select your device, and when it
3682 asks for the code, enter '1234'.
3685 Subsequent connections will not require you to enter that
3686 code, and your 'paired' device will appear in the list without
3691 <title>Configuring AltosDroid</title>
3693 The only configuration option available for AltosDroid is
3694 which frequency to listen on. Press the Android 'Menu' button
3695 or soft-key and pick the 'Select radio frequency' entry. That
3696 brings up a menu of pre-set radio frequencies; pick the one
3697 which matches your altimeter.
3701 <title>AltosDroid Flight Monitoring</title>
3703 AltosDroid is designed to mimic the AltosUI flight monitoring
3704 display, providing separate tabs for each stage of your rocket
3705 flight along with a tab containing a map of the local area
3706 with icons marking the current location of the altimeter and
3712 The 'Launch Pad' tab shows information used to decide when the
3713 rocket is ready for flight. The first elements include red/green
3714 indicators, if any of these is red, you'll want to evaluate
3715 whether the rocket is ready to launch:
3718 <term>Battery Voltage</term>
3721 This indicates whether the Li-Po battery
3722 powering the TeleMetrum has sufficient charge to last for
3723 the duration of the flight. A value of more than
3724 3.8V is required for a 'GO' status.
3729 <term>Apogee Igniter Voltage</term>
3732 This indicates whether the apogee
3733 igniter has continuity. If the igniter has a low
3734 resistance, then the voltage measured here will be close
3735 to the Li-Po battery voltage. A value greater than 3.2V is
3736 required for a 'GO' status.
3741 <term>Main Igniter Voltage</term>
3744 This indicates whether the main
3745 igniter has continuity. If the igniter has a low
3746 resistance, then the voltage measured here will be close
3747 to the Li-Po battery voltage. A value greater than 3.2V is
3748 required for a 'GO' status.
3753 <term>On-board Data Logging</term>
3756 This indicates whether there is
3757 space remaining on-board to store flight data for the
3758 upcoming flight. If you've downloaded data, but failed
3759 to erase flights, there may not be any space
3760 left. TeleMetrum can store multiple flights, depending
3761 on the configured maximum flight log size. TeleMini
3762 stores only a single flight, so it will need to be
3763 downloaded and erased after each flight to capture
3764 data. This only affects on-board flight logging; the
3765 altimeter will still transmit telemetry and fire
3766 ejection charges at the proper times.
3771 <term>GPS Locked</term>
3774 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
3775 currently able to compute position information. GPS requires
3776 at least 4 satellites to compute an accurate position.
3781 <term>GPS Ready</term>
3784 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
3785 10 consecutive positions without losing lock. This ensures
3786 that the GPS receiver has reliable reception from the
3794 The Launchpad tab also shows the computed launch pad position
3795 and altitude, averaging many reported positions to improve the
3796 accuracy of the fix.
3801 <title>Downloading Flight Logs</title>
3803 AltosDroid always saves every bit of telemetry data it
3804 receives. To download that to a computer for use with AltosUI,
3805 simply remove the SD card from your Android device, or connect
3806 your device to your computer's USB port and browse the files
3807 on that device. You will find '.telem' files in the TeleMetrum
3808 directory that will work with AltosUI directly.
3813 <title>Using Altus Metrum Products</title>
3815 <title>Being Legal</title>
projects / fw / altos / blob