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>1.3.2</revnumber>
45 <date>24 January 2014</date>
47 Bug fixes for TeleMega and AltosUI.
51 <revnumber>1.3.1</revnumber>
52 <date>21 January 2014</date>
54 Bug fixes for TeleMega and TeleMetrum v2.0 along with a few
55 small UI improvements.
59 <revnumber>1.3</revnumber>
60 <date>12 November 2013</date>
62 Updated for software version 1.3. Version 1.3 adds support
63 for TeleMega, TeleMetrum v2.0, TeleMini v2.0 and EasyMini
64 and fixes bugs in AltosUI and the AltOS firmware.
68 <revnumber>1.2.1</revnumber>
69 <date>21 May 2013</date>
71 Updated for software version 1.2. Version 1.2 adds support
72 for TeleBT and AltosDroid. It also adds a few minor features
73 and fixes bugs in AltosUI and the AltOS firmware.
77 <revnumber>1.2</revnumber>
78 <date>18 April 2013</date>
80 Updated for software version 1.2. Version 1.2 adds support
81 for MicroPeak and the MicroPeak USB interface.
85 <revnumber>1.1.1</revnumber>
86 <date>16 September 2012</date>
88 Updated for software version 1.1.1 Version 1.1.1 fixes a few
89 bugs found in version 1.1.
93 <revnumber>1.1</revnumber>
94 <date>13 September 2012</date>
96 Updated for software version 1.1. Version 1.1 has new
97 features but is otherwise compatible with version 1.0.
101 <revnumber>1.0</revnumber>
102 <date>24 August 2011</date>
104 Updated for software version 1.0. Note that 1.0 represents a
105 telemetry format change, meaning both ends of a link
106 (TeleMetrum/TeleMini and TeleDongle) must be updated or
107 communications will fail.
111 <revnumber>0.9</revnumber>
112 <date>18 January 2011</date>
114 Updated for software version 0.9. Note that 0.9 represents a
115 telemetry format change, meaning both ends of a link (TeleMetrum and
116 TeleDongle) must be updated or communications will fail.
120 <revnumber>0.8</revnumber>
121 <date>24 November 2010</date>
122 <revremark>Updated for software version 0.8 </revremark>
127 <title>Acknowledgments</title>
129 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing “The
130 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
131 Kit” which formed the basis of the original Getting Started chapter
132 in this manual. Bob was one of our first customers for a production
133 TeleMetrum, and his continued enthusiasm and contributions
134 are immensely gratifying and highly appreciated!
137 And thanks to Anthony (AJ) Towns for major contributions including
138 the AltosUI graphing and site map code and associated documentation.
139 Free software means that our customers and friends can become our
140 collaborators, and we certainly appreciate this level of
144 Have fun using these products, and we hope to meet all of you
145 out on the rocket flight line somewhere.
148 NAR #87103, TRA #12201
150 Keith Packard, KD7SQG
151 NAR #88757, TRA #12200
156 <title>Introduction and Overview</title>
158 Welcome to the Altus Metrum community! Our circuits and software reflect
159 our passion for both hobby rocketry and Free Software. We hope their
160 capabilities and performance will delight you in every way, but by
161 releasing all of our hardware and software designs under open licenses,
162 we also hope to empower you to take as active a role in our collective
166 The first device created for our community was TeleMetrum, a dual
167 deploy altimeter with fully integrated GPS and radio telemetry
168 as standard features, and a “companion interface” that will
169 support optional capabilities in the future. The latest version
170 of TeleMetrum, v2.0, has all of the same features but with
171 improved sensors and radio to offer increased performance.
174 Our second device was TeleMini, a dual deploy altimeter with
175 radio telemetry and radio direction finding. The first version
176 of this device was only 13mm by 38mm (½ inch by 1½ inches) and
177 could fit easily in an 18mm air-frame. The latest version, v2.0,
178 includes a beeper, USB data download and extended on-board
179 flight logging, along with an improved barometric sensor.
182 TeleMega is our most sophisticated device, including six pyro
183 channels (four of which are fully programmable), integrated GPS,
184 integrated gyroscopes for staging/air-start inhibit and high
185 performance telemetry.
188 EasyMini is a dual-deploy altimeter with logging and built-in
192 TeleDongle was our first ground station, providing a USB to RF
193 interfaces for communicating with the altimeters. Combined with
194 your choice of antenna and notebook computer, TeleDongle and our
195 associated user interface software form a complete ground
196 station capable of logging and displaying in-flight telemetry,
197 aiding rocket recovery, then processing and archiving flight
198 data for analysis and review.
201 For a slightly more portable ground station experience that also
202 provides direct rocket recovery support, TeleBT offers flight
203 monitoring and data logging using a Bluetooth™ connection between
204 the receiver and an Android device that has the AltosDroid
205 application installed from the Google Play store.
208 More products will be added to the Altus Metrum family over time, and
209 we currently envision that this will be a single, comprehensive manual
210 for the entire product family.
214 <title>Getting Started</title>
216 The first thing to do after you check the inventory of parts in your
217 “starter kit” is to charge the battery.
220 For TeleMetrum and TeleMega, the battery can be charged by plugging it into the
221 corresponding socket of the device and then using the USB
222 cable to plug the flight computer into your computer's USB socket. The
223 on-board circuitry will charge the battery whenever it is plugged
224 in, because the on-off switch does NOT control the
228 On TeleMetrum v1 boards, when the GPS chip is initially
229 searching for satellites, TeleMetrum will consume more current
230 than it pulls from the USB port, so the battery must be
231 attached in order to get satellite lock. Once GPS is locked,
232 the current consumption goes back down enough to enable charging
233 while running. So it's a good idea to fully charge the battery
234 as your first item of business so there is no issue getting and
235 maintaining satellite lock. The yellow charge indicator led
236 will go out when the battery is nearly full and the charger goes
237 to trickle charge. It can take several hours to fully recharge a
238 deeply discharged battery.
241 TeleMetrum v2.0 and TeleMega use a higher power battery charger,
242 allowing them to charge the battery while running the board at
243 maximum power. When the battery is charging, or when the board
244 is consuming a lot of power, the red LED will be lit. When the
245 battery is fully charged, the green LED will be lit. When the
246 battery is damaged or missing, both LEDs will be lit, which
250 The Lithium Polymer TeleMini and EasyMini battery can be charged by
251 disconnecting it from the board and plugging it into a
252 standalone battery charger such as the LipoCharger product
253 included in TeleMini Starter Kits, and connecting that via a USB
254 cable to a laptop or other USB power source.
257 You can also choose to use another battery with TeleMini v2.0
258 and EasyMini, anything supplying between 4 and 12 volts should
259 work fine (like a standard 9V battery), but if you are planning
260 to fire pyro charges, ground testing is required to verify that
261 the battery supplies enough current to fire your chosen e-matches.
264 The other active device in the starter kit is the TeleDongle USB to
265 RF interface. If you plug it in to your Mac or Linux computer it should
266 “just work”, showing up as a serial port device. Windows systems need
267 driver information that is part of the AltOS download to know that the
268 existing USB modem driver will work. We therefore recommend installing
269 our software before plugging in TeleDongle if you are using a Windows
270 computer. If you are using an older version of Linux and are having
271 problems, try moving to a fresher kernel (2.6.33 or newer).
274 Next you should obtain and install the AltOS software. The AltOS
275 distribution includes the AltosUI ground station program, current
277 images for all of the hardware, and a number of standalone
278 utilities that are rarely needed. Pre-built binary packages are
279 available for Linux, Microsoft Windows, and recent MacOSX
280 versions. Full source code and build instructions are also
281 available. The latest version may always be downloaded from
282 <ulink url="http://altusmetrum.org/AltOS"/>.
285 If you're using a TeleBT instead of the TeleDongle, you'll want to
286 install the AltosDroid application from the Google Play store on an
287 Android device. You don't need a data plan to use AltosDroid, but
288 without network access, the Map view will be less useful as it
289 won't contain any map data. You can also use TeleBT connected
290 over USB with your laptop computer; it acts exactly like a
291 TeleDongle. Anywhere this manual talks about TeleDongle, you can
292 also read that as 'and TeleBT when connected via USB'.
296 <title>Handling Precautions</title>
298 All Altus Metrum products are sophisticated electronic devices.
299 When handled gently and properly installed in an air-frame, they
300 will deliver impressive results. However, as with all electronic
301 devices, there are some precautions you must take.
304 The Lithium Polymer rechargeable batteries have an
305 extraordinary power density. This is great because we can fly with
306 much less battery mass than if we used alkaline batteries or previous
307 generation rechargeable batteries... but if they are punctured
308 or their leads are allowed to short, they can and will release their
310 Thus we recommend that you take some care when handling our batteries
311 and consider giving them some extra protection in your air-frame. We
312 often wrap them in suitable scraps of closed-cell packing foam before
313 strapping them down, for example.
316 The barometric sensors used on all of our flight computers are
317 sensitive to sunlight. In normal mounting situations, the baro sensor
318 and all of the other surface mount components
319 are “down” towards whatever the underlying mounting surface is, so
320 this is not normally a problem. Please consider this when designing an
321 installation in an air-frame with a see-through plastic payload bay. It
322 is particularly important to
323 consider this with TeleMini v1.0, both because the baro sensor is on the
324 “top” of the board, and because many model rockets with payload bays
325 use clear plastic for the payload bay! Replacing these with an opaque
326 cardboard tube, painting them, or wrapping them with a layer of masking
327 tape are all reasonable approaches to keep the sensor out of direct
331 The barometric sensor sampling port must be able to “breathe”,
332 both by not being covered by foam or tape or other materials that might
333 directly block the hole on the top of the sensor, and also by having a
334 suitable static vent to outside air.
337 As with all other rocketry electronics, Altus Metrum altimeters must
338 be protected from exposure to corrosive motor exhaust and ejection
343 <title>Altus Metrum Hardware</title>
345 <title>General Usage Instructions</title>
347 Here are general instructions for hooking up an Altus Metrum
348 flight computer. Instructions specific to each model will be
349 found in the section devoted to that model below.
352 To prevent electrical interference from affecting the
353 operation of the flight computer, it's important to always
354 twist pairs of wires connected to the board. Twist the switch
355 leads, the pyro leads and the battery leads. This reduces
356 interference through a mechanism called common mode rejection.
359 <title>Hooking Up Lithium Polymer Batteries</title>
361 All Altus Metrum flight computers have a two pin JST PH
362 series connector to connect up a single-cell Lithium Polymer
363 cell (3.7V nominal). You can purchase matching batteries
364 from the Altus Metrum store, or other vendors, or you can
365 make your own. Pin 1 of the connector is positive, pin 2 is
366 negative. Spark Fun sells a cable with the connector
367 attached, which they call a <ulink
368 url="https://www.sparkfun.com/products/9914">JST Jumper 2
369 Wire Assembly</ulink>.
372 Many RC vendors also sell lithium polymer batteries with
373 this same connector. All that we have found use the opposite
374 polarity, and if you use them that way, you will damage or
375 destroy the flight computer.
379 <title>Hooking Up Pyro Charges</title>
381 Altus Metrum flight computers always have two screws for
382 each pyro charge. This means you shouldn't need to put two
383 wires into a screw terminal or connect leads from pyro
384 charges together externally.
387 On the flight computer, one lead from each charge is hooked
388 to the positive battery terminal through the power switch.
389 The other lead is connected through the pyro circuit, which
390 is connected to the negative battery terminal when the pyro
395 <title>Hooking Up a Power Switch</title>
397 Altus Metrum flight computers need an external power switch
398 to turn them on. This disconnects both the computer and the
399 pyro charges from the battery, preventing the charges from
400 firing when in the Off position. The switch is in-line with
401 the positive battery terminal.
404 <title>Using an External Active Switch Circuit</title>
406 You can use an active switch circuit, such as the
407 Featherweight Magnetic Switch, with any Altus Metrum
408 flight computer. These require three connections, one to
409 the battery, one to the positive power input on the flight
410 computer and one to ground. Find instructions on how to
411 hook these up for each flight computer below. The follow
412 the instructions that come with your active switch to
418 <title>Using a Separate Pyro Battery</title>
420 As mentioned above in the section on hooking up pyro
421 charges, one lead for each of the pyro charges is connected
422 through the power switch directly to the positive battery
423 terminal. The other lead is connected to the pyro circuit,
424 which connects it to the negative battery terminal when the
425 pyro circuit is fired. The pyro circuit on all of the flight
426 computers is designed to handle up to 16V.
429 To use a separate pyro battery, connect the negative pyro
430 battery terminal to the flight computer ground terminal,
431 the positive battery terminal to the igniter and the other
432 igniter lead to the negative pyro terminal on the flight
433 computer. When the pyro channel fires, it will complete the
434 circuit between the negative pyro terminal and the ground
435 terminal, firing the igniter. Specific instructions on how
436 to hook this up will be found in each section below.
440 <title>Using a Different Kind of Battery</title>
442 EasyMini and TeleMini v2 are designed to use either a
443 lithium polymer battery or any other battery producing
444 between 4 and 12 volts, such as a rectangular 9V
445 battery. TeleMega and TeleMetrum are not designed for this,
446 and must only be powered by a lithium polymer battery. Find
447 instructions on how to use other batteries in the EasyMini
448 and TeleMini sections below.
453 <title>Specifications</title>
455 Here's the full set of Altus Metrum products, both in
456 production and retired.
459 <title>Altus Metrum Electronics</title>
460 <?dbfo keep-together="always"?>
461 <tgroup cols='8' align='center' colsep='1' rowsep='1'>
462 <colspec align='center' colwidth='*' colname='Device'/>
463 <colspec align='center' colwidth='*' colname='Barometer'/>
464 <colspec align='center' colwidth='*' colname='Z-axis accelerometer'/>
465 <colspec align='center' colwidth='*' colname='GPS'/>
466 <colspec align='center' colwidth='*' colname='3D sensors'/>
467 <colspec align='center' colwidth='*' colname='Storage'/>
468 <colspec align='center' colwidth='*' colname='RF'/>
469 <colspec align='center' colwidth='*' colname='Battery'/>
472 <entry align='center'>Device</entry>
473 <entry align='center'>Barometer</entry>
474 <entry align='center'>Z-axis accelerometer</entry>
475 <entry align='center'>GPS</entry>
476 <entry align='center'>3D sensors</entry>
477 <entry align='center'>Storage</entry>
478 <entry align='center'>RF Output</entry>
479 <entry align='center'>Battery</entry>
484 <entry>TeleMetrum v1.0</entry>
485 <entry><para>MP3H6115 10km (33k')</para></entry>
486 <entry><para>MMA2202 50g</para></entry>
487 <entry>SkyTraq</entry>
494 <entry>TeleMetrum v1.1</entry>
495 <entry><para>MP3H6115 10km (33k')</para></entry>
496 <entry><para>MMA2202 50g</para></entry>
497 <entry>SkyTraq</entry>
504 <entry>TeleMetrum v1.2</entry>
505 <entry><para>MP3H6115 10km (33k')</para></entry>
506 <entry><para>ADXL78 70g</para></entry>
507 <entry>SkyTraq</entry>
514 <entry>TeleMetrum v2.0</entry>
515 <entry><para>MS5607 30km (100k')</para></entry>
516 <entry><para>MMA6555 102g</para></entry>
517 <entry>uBlox Max-7Q</entry>
524 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
525 <entry><para>MP3H6115 10km (33k')</para></entry>
534 <entry>TeleMini <?linebreak?>v2.0</entry>
535 <entry><para>MS5607 30km (100k')</para></entry>
541 <entry>3.7-12V</entry>
544 <entry>EasyMini <?linebreak?>v1.0</entry>
545 <entry><para>MS5607 30km (100k')</para></entry>
551 <entry>3.7-12V</entry>
554 <entry>TeleMega <?linebreak?>v1.0</entry>
555 <entry><para>MS5607 30km (100k')</para></entry>
556 <entry><para>MMA6555 102g</para></entry>
557 <entry>uBlox Max-7Q</entry>
558 <entry><para>MPU6000 HMC5883</para></entry>
567 <title>Altus Metrum Boards</title>
568 <?dbfo keep-together="always"?>
569 <tgroup cols='6' align='center' colsep='1' rowsep='1'>
570 <colspec align='center' colwidth='*' colname='Device'/>
571 <colspec align='center' colwidth='*' colname='Connectors'/>
572 <colspec align='center' colwidth='*' colname='Screw Terminals'/>
573 <colspec align='center' colwidth='*' colname='Width'/>
574 <colspec align='center' colwidth='*' colname='Length'/>
575 <colspec align='center' colwidth='*' colname='Tube Size'/>
578 <entry align='center'>Device</entry>
579 <entry align='center'>Connectors</entry>
580 <entry align='center'>Screw Terminals</entry>
581 <entry align='center'>Width</entry>
582 <entry align='center'>Length</entry>
583 <entry align='center'>Tube Size</entry>
588 <entry>TeleMetrum</entry>
592 Companion<?linebreak?>
596 <entry><para>Apogee pyro <?linebreak?>Main pyro <?linebreak?>Switch</para></entry>
597 <entry>1 inch (2.54cm)</entry>
598 <entry>2 ¾ inch (6.99cm)</entry>
599 <entry>29mm coupler</entry>
602 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
609 Apogee pyro <?linebreak?>
612 <entry>½ inch (1.27cm)</entry>
613 <entry>1½ inch (3.81cm)</entry>
614 <entry>18mm coupler</entry>
617 <entry>TeleMini <?linebreak?>v2.0</entry>
625 Apogee pyro <?linebreak?>
626 Main pyro <?linebreak?>
627 Battery <?linebreak?>
630 <entry>0.8 inch (2.03cm)</entry>
631 <entry>1½ inch (3.81cm)</entry>
632 <entry>24mm coupler</entry>
635 <entry>EasyMini</entry>
642 Apogee pyro <?linebreak?>
643 Main pyro <?linebreak?>
644 Battery <?linebreak?>
647 <entry>0.8 inch (2.03cm)</entry>
648 <entry>1½ inch (3.81cm)</entry>
649 <entry>24mm coupler</entry>
652 <entry>TeleMega</entry>
656 Companion<?linebreak?>
661 Apogee pyro <?linebreak?>
662 Main pyro<?linebreak?>
663 Pyro A-D<?linebreak?>
667 <entry>1¼ inch (3.18cm)</entry>
668 <entry>3¼ inch (8.26cm)</entry>
669 <entry>38mm coupler</entry>
676 <title>TeleMetrum</title>
680 <imagedata fileref="telemetrum-v1.1-thside.jpg" width="5.5in" scalefit="1"/>
685 TeleMetrum is a 1 inch by 2¾ inch circuit board. It was designed to
686 fit inside coupler for 29mm air-frame tubing, but using it in a tube that
687 small in diameter may require some creativity in mounting and wiring
688 to succeed! The presence of an accelerometer means TeleMetrum should
689 be aligned along the flight axis of the airframe, and by default the ¼
690 wave UHF wire antenna should be on the nose-cone end of the board. The
691 antenna wire is about 7 inches long, and wiring for a power switch and
692 the e-matches for apogee and main ejection charges depart from the
693 fin can end of the board, meaning an ideal “simple” avionics
694 bay for TeleMetrum should have at least 10 inches of interior length.
697 <title>TeleMetrum Screw Terminals</title>
699 TeleMetrum has six screw terminals on the end of the board
700 opposite the telemetry antenna. Two are for the power
701 switch, and two each for the apogee and main igniter
702 circuits. Using the picture above and starting from the top,
703 the terminals are as follows:
706 <title>TeleMetrum Screw Terminals</title>
707 <?dbfo keep-together="always"?>
708 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
709 <colspec align='center' colwidth='*' colname='Pin #'/>
710 <colspec align='center' colwidth='2*' colname='Pin Name'/>
711 <colspec align='left' colwidth='5*' colname='Description'/>
714 <entry align='center'>Terminal #</entry>
715 <entry align='center'>Terminal Name</entry>
716 <entry align='center'>Description</entry>
722 <entry>Switch Output</entry>
723 <entry>Switch connection to flight computer</entry>
727 <entry>Switch Input</entry>
728 <entry>Switch connection to positive battery terminal</entry>
732 <entry>Main +</entry>
733 <entry>Main pyro channel common connection to battery +</entry>
737 <entry>Main -</entry>
738 <entry>Main pyro channel connection to pyro circuit</entry>
742 <entry>Apogee +</entry>
743 <entry>Apogee pyro channel common connection to battery +</entry>
747 <entry>Apogee -</entry>
748 <entry>Apogee pyro channel connection to pyro circuit</entry>
755 <title>Using a Separate Pyro Battery with TeleMetrum</title>
757 As described above, using an external pyro battery involves
758 connecting the negative battery terminal to the flight
759 computer ground, connecting the positive battery terminal to
760 one of the igniter leads and connecting the other igniter
761 lead to the per-channel pyro circuit connection.
764 To connect the negative battery terminal to the TeleMetrum
765 ground, insert a small piece of wire, 24 to 28 gauge
766 stranded, into the GND hole just above the screw terminal
767 strip and solder it in place.
770 Connecting the positive battery terminal to the pyro
771 charges must be done separate from TeleMetrum, by soldering
772 them together or using some other connector.
775 The other lead from each pyro charge is then inserted into
776 the appropriate per-pyro channel screw terminal (terminal 4 for the
777 Main charge, terminal 6 for the Apogee charge).
781 <title>Using an Active Switch with TeleMetrum</title>
783 As explained above, an external active switch requires three
784 connections, one to the positive battery terminal, one to
785 the flight computer positive input and one to ground.
788 The positive battery terminal is available on screw terminal
789 2, the positive flight computer input is on terminal 1. To
790 hook a lead to ground, solder a piece of wire, 24 to 28
791 gauge stranded, to the GND hole just above terminal 1.
796 <title>TeleMini v1.0</title>
800 <imagedata fileref="telemini-v1-top.jpg" width="5.5in" scalefit="1"/>
805 TeleMini v1.0 is ½ inches by 1½ inches. It was
806 designed to fit inside an 18mm air-frame tube, but using it in
807 a tube that small in diameter may require some creativity in
808 mounting and wiring to succeed! Since there is no
809 accelerometer, TeleMini can be mounted in any convenient
810 orientation. The default ¼ wave UHF wire antenna attached to
811 the center of one end of the board is about 7 inches long. Two
812 wires for the power switch are connected to holes in the
813 middle of the board. Screw terminals for the e-matches for
814 apogee and main ejection charges depart from the other end of
815 the board, meaning an ideal “simple” avionics bay for TeleMini
816 should have at least 9 inches of interior length.
819 <title>TeleMini v1.0 Screw Terminals</title>
821 TeleMini v1.0 has four screw terminals on the end of the
822 board opposite the telemetry antenna. Two are for the apogee
823 and two are for main igniter circuits. There are also wires
824 soldered to the board for the power switch. Using the
825 picture above and starting from the top for the terminals
826 and from the left for the power switch wires, the
827 connections are as follows:
830 <title>TeleMini v1.0 Connections</title>
831 <?dbfo keep-together="always"?>
832 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
833 <colspec align='center' colwidth='*' colname='Pin #'/>
834 <colspec align='center' colwidth='2*' colname='Pin Name'/>
835 <colspec align='left' colwidth='5*' colname='Description'/>
838 <entry align='center'>Terminal #</entry>
839 <entry align='center'>Terminal Name</entry>
840 <entry align='center'>Description</entry>
846 <entry>Apogee -</entry>
847 <entry>Apogee pyro channel connection to pyro circuit</entry>
851 <entry>Apogee +</entry>
852 <entry>Apogee pyro channel common connection to battery +</entry>
856 <entry>Main -</entry>
857 <entry>Main pyro channel connection to pyro circuit</entry>
861 <entry>Main +</entry>
862 <entry>Main pyro channel common connection to battery +</entry>
866 <entry>Switch Output</entry>
867 <entry>Switch connection to flight computer</entry>
871 <entry>Switch Input</entry>
872 <entry>Switch connection to positive battery terminal</entry>
879 <title>Using a Separate Pyro Battery with TeleMini v1.0</title>
881 As described above, using an external pyro battery involves
882 connecting the negative battery terminal to the flight
883 computer ground, connecting the positive battery terminal to
884 one of the igniter leads and connecting the other igniter
885 lead to the per-channel pyro circuit connection. Because
886 there is no solid ground connection to use on TeleMini, this
890 The only available ground connection on TeleMini v1.0 are
891 the two mounting holes next to the telemetry
892 antenna. Somehow connect a small piece of wire to one of
893 those holes and hook it to the negative pyro battery terminal.
896 Connecting the positive battery terminal to the pyro
897 charges must be done separate from TeleMini v1.0, by soldering
898 them together or using some other connector.
901 The other lead from each pyro charge is then inserted into
902 the appropriate per-pyro channel screw terminal (terminal 3 for the
903 Main charge, terminal 1 for the Apogee charge).
907 <title>Using an Active Switch with TeleMini v1.0</title>
909 As explained above, an external active switch requires three
910 connections, one to the positive battery terminal, one to
911 the flight computer positive input and one to ground. Again,
912 because TeleMini doesn't have any good ground connection,
913 this is not recommended.
916 The positive battery terminal is available on the Right
917 power switch wire, the positive flight computer input is on
918 the left power switch wire. Hook a lead to either of the
919 mounting holes for a ground connection.
924 <title>TeleMini v2.0</title>
928 <imagedata fileref="telemini-v2-top.jpg" width="5.5in" scalefit="1"/>
933 TeleMini v2.0 is 0.8 inches by 1½ inches. It adds more
934 on-board data logging memory, a built-in USB connector and
935 screw terminals for the battery and power switch. The larger
936 board fits in a 24mm coupler. There's also a battery connector
937 for a LiPo battery if you want to use one of those.
940 <title>TeleMini v2.0 Screw Terminals</title>
942 TeleMini v2.0 has two sets of four screw terminals on the end of the
943 board opposite the telemetry antenna. Using the picture
944 above, the top four have connections for the main pyro
945 circuit and an external battery and the bottom four have
946 connections for the apogee pyro circuit and the power
947 switch. Counting from the left, the connections are as follows:
950 <title>TeleMini v2.0 Connections</title>
951 <?dbfo keep-together="always"?>
952 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
953 <colspec align='center' colwidth='*' colname='Pin #'/>
954 <colspec align='center' colwidth='2*' colname='Pin Name'/>
955 <colspec align='left' colwidth='5*' colname='Description'/>
958 <entry align='center'>Terminal #</entry>
959 <entry align='center'>Terminal Name</entry>
960 <entry align='center'>Description</entry>
966 <entry>Main -</entry>
967 <entry>Main pyro channel connection to pyro circuit</entry>
971 <entry>Main +</entry>
972 <entry>Main pyro channel common connection to battery +</entry>
976 <entry>Battery +</entry>
977 <entry>Positive external battery terminal</entry>
981 <entry>Battery -</entry>
982 <entry>Negative external battery terminal</entry>
985 <entry>Bottom 1</entry>
986 <entry>Apogee -</entry>
987 <entry>Apogee pyro channel connection to pyro circuit</entry>
990 <entry>Bottom 2</entry>
991 <entry>Apogee +</entry>
992 <entry>Apogee pyro channel common connection to
996 <entry>Bottom 3</entry>
997 <entry>Switch Output</entry>
998 <entry>Switch connection to flight computer</entry>
1001 <entry>Bottom 4</entry>
1002 <entry>Switch Input</entry>
1003 <entry>Switch connection to positive battery terminal</entry>
1010 <title>Using a Separate Pyro Battery with TeleMini v2.0</title>
1012 As described above, using an external pyro battery involves
1013 connecting the negative battery terminal to the flight
1014 computer ground, connecting the positive battery terminal to
1015 one of the igniter leads and connecting the other igniter
1016 lead to the per-channel pyro circuit connection.
1019 To connect the negative pyro battery terminal to TeleMini
1020 ground, connect it to the negative external battery
1021 connection, top terminal 4.
1024 Connecting the positive battery terminal to the pyro
1025 charges must be done separate from TeleMini v2.0, by soldering
1026 them together or using some other connector.
1029 The other lead from each pyro charge is then inserted into
1030 the appropriate per-pyro channel screw terminal (top
1031 terminal 1 for the Main charge, bottom terminal 1 for the
1036 <title>Using an Active Switch with TeleMini v2.0</title>
1038 As explained above, an external active switch requires three
1039 connections, one to the positive battery terminal, one to
1040 the flight computer positive input and one to ground. Use
1041 the negative external battery connection, top terminal 4 for
1045 The positive battery terminal is available on bottom
1046 terminal 4, the positive flight computer input is on the
1052 <title>EasyMini</title>
1056 <imagedata fileref="easymini-top.jpg" width="5.5in" scalefit="1"/>
1061 EasyMini is built on a 0.8 inch by 1½ inch circuit board. It's
1062 designed to fit in a 24mm coupler tube. The connectors and
1063 screw terminals match TeleMini v2.0, so you can easily swap between
1064 EasyMini and TeleMini.
1067 <title>EasyMini Screw Terminals</title>
1069 EasyMini has two sets of four screw terminals on the end of the
1070 board opposite the telemetry antenna. Using the picture
1071 above, the top four have connections for the main pyro
1072 circuit and an external battery and the bottom four have
1073 connections for the apogee pyro circuit and the power
1074 switch. Counting from the left, the connections are as follows:
1077 <title>EasyMini Connections</title>
1078 <?dbfo keep-together="always"?>
1079 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
1080 <colspec align='center' colwidth='*' colname='Pin #'/>
1081 <colspec align='center' colwidth='2*' colname='Pin Name'/>
1082 <colspec align='left' colwidth='5*' colname='Description'/>
1085 <entry align='center'>Terminal #</entry>
1086 <entry align='center'>Terminal Name</entry>
1087 <entry align='center'>Description</entry>
1092 <entry>Top 1</entry>
1093 <entry>Main -</entry>
1094 <entry>Main pyro channel connection to pyro circuit</entry>
1097 <entry>Top 2</entry>
1098 <entry>Main +</entry>
1099 <entry>Main pyro channel common connection to battery +</entry>
1102 <entry>Top 3</entry>
1103 <entry>Battery +</entry>
1104 <entry>Positive external battery terminal</entry>
1107 <entry>Top 4</entry>
1108 <entry>Battery -</entry>
1109 <entry>Negative external battery terminal</entry>
1112 <entry>Bottom 1</entry>
1113 <entry>Apogee -</entry>
1114 <entry>Apogee pyro channel connection to pyro circuit</entry>
1117 <entry>Bottom 2</entry>
1118 <entry>Apogee +</entry>
1119 <entry>Apogee pyro channel common connection to
1123 <entry>Bottom 3</entry>
1124 <entry>Switch Output</entry>
1125 <entry>Switch connection to flight computer</entry>
1128 <entry>Bottom 4</entry>
1129 <entry>Switch Input</entry>
1130 <entry>Switch connection to positive battery terminal</entry>
1137 <title>Using a Separate Pyro Battery with EasyMini</title>
1139 As described above, using an external pyro battery involves
1140 connecting the negative battery terminal to the flight
1141 computer ground, connecting the positive battery terminal to
1142 one of the igniter leads and connecting the other igniter
1143 lead to the per-channel pyro circuit connection.
1146 To connect the negative pyro battery terminal to TeleMini
1147 ground, connect it to the negative external battery
1148 connection, top terminal 4.
1151 Connecting the positive battery terminal to the pyro
1152 charges must be done separate from EasyMini, by soldering
1153 them together or using some other connector.
1156 The other lead from each pyro charge is then inserted into
1157 the appropriate per-pyro channel screw terminal (top
1158 terminal 1 for the Main charge, bottom terminal 1 for the
1163 <title>Using an Active Switch with EasyMini</title>
1165 As explained above, an external active switch requires three
1166 connections, one to the positive battery terminal, one to
1167 the flight computer positive input and one to ground. Use
1168 the negative external battery connection, top terminal 4 for
1172 The positive battery terminal is available on bottom
1173 terminal 4, the positive flight computer input is on the
1179 <title>TeleMega</title>
1183 <imagedata fileref="telemega-v1.0-top.jpg" width="5.5in" scalefit="1"/>
1188 TeleMega is a 1¼ inch by 3¼ inch circuit board. It was
1189 designed to easily fit in a 38mm coupler. Like TeleMetrum,
1190 TeleMega has an accelerometer and so it must be mounted so that
1191 the board is aligned with the flight axis. It can be mounted
1192 either antenna up or down.
1195 <title>TeleMega Screw Terminals</title>
1197 TeleMega has two sets of nine screw terminals on the end of
1198 the board opposite the telemetry antenna. They are as follows:
1201 <title>TeleMega Screw Terminals</title>
1202 <?dbfo keep-together="always"?>
1203 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
1204 <colspec align='center' colwidth='*' colname='Pin #'/>
1205 <colspec align='center' colwidth='2*' colname='Pin Name'/>
1206 <colspec align='left' colwidth='5*' colname='Description'/>
1209 <entry align='center'>Terminal #</entry>
1210 <entry align='center'>Terminal Name</entry>
1211 <entry align='center'>Description</entry>
1216 <entry>Top 1</entry>
1217 <entry>Switch Input</entry>
1218 <entry>Switch connection to positive battery terminal</entry>
1221 <entry>Top 2</entry>
1222 <entry>Switch Output</entry>
1223 <entry>Switch connection to flight computer</entry>
1226 <entry>Top 3</entry>
1228 <entry>Ground connection for use with external active switch</entry>
1231 <entry>Top 4</entry>
1232 <entry>Main -</entry>
1233 <entry>Main pyro channel connection to pyro circuit</entry>
1236 <entry>Top 5</entry>
1237 <entry>Main +</entry>
1238 <entry>Main pyro channel common connection to battery +</entry>
1241 <entry>Top 6</entry>
1242 <entry>Apogee -</entry>
1243 <entry>Apogee pyro channel connection to pyro circuit</entry>
1246 <entry>Top 7</entry>
1247 <entry>Apogee +</entry>
1248 <entry>Apogee pyro channel common connection to battery +</entry>
1251 <entry>Top 8</entry>
1253 <entry>D pyro channel connection to pyro circuit</entry>
1256 <entry>Top 9</entry>
1258 <entry>D pyro channel common connection to battery +</entry>
1261 <entry>Bottom 1</entry>
1263 <entry>Ground connection for negative pyro battery terminal</entry>
1266 <entry>Bottom 2</entry>
1268 <entry>Positive pyro battery terminal</entry>
1271 <entry>Bottom 3</entry>
1274 Power switch output. Use to connect main battery to
1279 <entry>Bottom 4</entry>
1281 <entry>A pyro channel connection to pyro circuit</entry>
1284 <entry>Bottom 5</entry>
1286 <entry>A pyro channel common connection to battery +</entry>
1289 <entry>Bottom 6</entry>
1291 <entry>B pyro channel connection to pyro circuit</entry>
1294 <entry>Bottom 7</entry>
1296 <entry>B pyro channel common connection to battery +</entry>
1299 <entry>Bottom 8</entry>
1301 <entry>C pyro channel connection to pyro circuit</entry>
1304 <entry>Bottom 9</entry>
1306 <entry>C pyro channel common connection to battery +</entry>
1313 <title>Using a Separate Pyro Battery with TeleMega</title>
1315 TeleMega provides explicit support for an external pyro
1316 battery. All that is required is to remove the jumper
1317 between the lipo terminal (Bottom 3) and the pyro terminal
1318 (Bottom 2). Then hook the negative pyro battery terminal to ground
1319 (Bottom 1) and the positive pyro battery to the pyro battery
1320 input (Bottom 2). You can then use the existing pyro screw
1321 terminals to hook up all of the pyro charges.
1325 <title>Using Only One Battery With TeleMega</title>
1327 Because TeleMega has built-in support for a separate pyro
1328 battery, if you want to fly with just one battery running
1329 both the computer and firing the charges, you need to
1330 connect the flight computer battery to the pyro
1331 circuit. TeleMega has two screw terminals for this—hook a
1332 wire from the Lipo terminal (Bottom 3) to the Pyro terminal
1337 <title>Using an Active Switch with TeleMega</title>
1339 As explained above, an external active switch requires three
1340 connections, one to the positive battery terminal, one to
1341 the flight computer positive input and one to ground.
1344 The positive battery terminal is available on Top terminal
1345 1, the positive flight computer input is on Top terminal
1346 2. Ground is on Top terminal 3.
1351 <title>Flight Data Recording</title>
1353 Each flight computer logs data at 100 samples per second
1354 during ascent and 10 samples per second during descent, except
1355 for TeleMini v1.0, which records ascent at 10 samples per
1356 second and descent at 1 sample per second. Data are logged to
1357 an on-board flash memory part, which can be partitioned into
1358 several equal-sized blocks, one for each flight.
1361 <title>Data Storage on Altus Metrum altimeters</title>
1362 <?dbfo keep-together="always"?>
1363 <tgroup cols='4' align='center' colsep='1' rowsep='1'>
1364 <colspec align='center' colwidth='*' colname='Device'/>
1365 <colspec align='center' colwidth='*' colname='Bytes per sample'/>
1366 <colspec align='center' colwidth='*' colname='Total storage'/>
1367 <colspec align='center' colwidth='*' colname='Minutes of
1371 <entry align='center'>Device</entry>
1372 <entry align='center'>Bytes per Sample</entry>
1373 <entry align='center'>Total Storage</entry>
1374 <entry align='center'>Minutes at Full Rate</entry>
1379 <entry>TeleMetrum v1.0</entry>
1385 <entry>TeleMetrum v1.1 v1.2</entry>
1391 <entry>TeleMetrum v2.0</entry>
1397 <entry>TeleMini v1.0</entry>
1403 <entry>TeleMini v2.0</entry>
1409 <entry>EasyMini</entry>
1415 <entry>TeleMega</entry>
1424 The on-board flash is partitioned into separate flight logs,
1425 each of a fixed maximum size. Increase the maximum size of
1426 each log and you reduce the number of flights that can be
1427 stored. Decrease the size and you can store more flights.
1430 Configuration data is also stored in the flash memory on
1431 TeleMetrum v1.x, TeleMini and EasyMini. This consumes 64kB
1432 of flash space. This configuration space is not available
1433 for storing flight log data. TeleMetrum v2.0 and TeleMega
1434 store configuration data in a bit of eeprom available within
1435 the processor chip, leaving that space available in flash for
1439 To compute the amount of space needed for a single flight, you
1440 can multiply the expected ascent time (in seconds) by 100
1441 times bytes-per-sample, multiply the expected descent time (in
1442 seconds) by 10 times the bytes per sample and add the two
1443 together. That will slightly under-estimate the storage (in
1444 bytes) needed for the flight. For instance, a TeleMetrum v2.0 flight spending
1445 20 seconds in ascent and 150 seconds in descent will take
1446 about (20 * 1600) + (150 * 160) = 56000 bytes of storage. You
1447 could store dozens of these flights in the on-board flash.
1450 The default size allows for several flights on each flight
1451 computer, except for TeleMini v1.0, which only holds data for a
1452 single flight. You can adjust the size.
1455 Altus Metrum flight computers will not overwrite existing
1456 flight data, so be sure to download flight data and erase it
1457 from the flight computer before it fills up. The flight
1458 computer will still successfully control the flight even if it
1459 cannot log data, so the only thing you will lose is the data.
1463 <title>Installation</title>
1465 A typical installation involves attaching
1466 only a suitable battery, a single pole switch for
1467 power on/off, and two pairs of wires connecting e-matches for the
1468 apogee and main ejection charges. All Altus Metrum products are
1469 designed for use with single-cell batteries with 3.7 volts
1470 nominal. TeleMini v2.0 and EasyMini may also be used with other
1471 batteries as long as they supply between 4 and 12 volts.
1474 The battery connectors are a standard 2-pin JST connector and
1475 match batteries sold by Spark Fun. These batteries are
1476 single-cell Lithium Polymer batteries that nominally provide 3.7
1477 volts. Other vendors sell similar batteries for RC aircraft
1478 using mating connectors, however the polarity for those is
1479 generally reversed from the batteries used by Altus Metrum
1480 products. In particular, the Tenergy batteries supplied for use
1481 in Featherweight flight computers are not compatible with Altus
1482 Metrum flight computers or battery chargers. <emphasis>Check
1483 polarity and voltage before connecting any battery not purchased
1484 from Altus Metrum or Spark Fun.</emphasis>
1487 By default, we use the unregulated output of the battery directly
1488 to fire ejection charges. This works marvelously with standard
1489 low-current e-matches like the J-Tek from MJG Technologies, and with
1490 Quest Q2G2 igniters. However, if you want or need to use a separate
1491 pyro battery, check out the “External Pyro Battery” section in this
1492 manual for instructions on how to wire that up. The altimeters are
1493 designed to work with an external pyro battery of no more than 15 volts.
1496 Ejection charges are wired directly to the screw terminal block
1497 at the aft end of the altimeter. You'll need a very small straight
1498 blade screwdriver for these screws, such as you might find in a
1499 jeweler's screwdriver set.
1502 Except for TeleMini v1.0, the flight computers also use the
1503 screw terminal block for the power switch leads. On TeleMini v1.0,
1504 the power switch leads are soldered directly to the board and
1505 can be connected directly to a switch.
1508 For most air-frames, the integrated antennas are more than
1509 adequate. However, if you are installing in a carbon-fiber or
1510 metal electronics bay which is opaque to RF signals, you may need to
1511 use off-board external antennas instead. In this case, you can
1512 replace the stock UHF antenna wire with an edge-launched SMA connector,
1513 and, on TeleMetrum v1, you can unplug the integrated GPS
1514 antenna and select an appropriate off-board GPS antenna with
1515 cable terminating in a U.FL connector.
1520 <title>System Operation</title>
1522 <title>Firmware Modes </title>
1524 The AltOS firmware build for the altimeters has two
1525 fundamental modes, “idle” and “flight”. Which of these modes
1526 the firmware operates in is determined at start up time. For
1527 TeleMetrum and TeleMega, which have accelerometers, the mode is
1528 controlled by the orientation of the
1529 rocket (well, actually the board, of course...) at the time
1530 power is switched on. If the rocket is “nose up”, then
1531 the flight computer assumes it's on a rail or rod being prepared for
1532 launch, so the firmware chooses flight mode. However, if the
1533 rocket is more or less horizontal, the firmware instead enters
1534 idle mode. Since TeleMini v2.0 and EasyMini don't have an
1535 accelerometer we can use to determine orientation, “idle” mode
1536 is selected if the board is connected via USB to a computer,
1537 otherwise the board enters “flight” mode. TeleMini v1.0
1538 selects “idle” mode if it receives a command packet within the
1539 first five seconds of operation.
1542 At power on, you will hear three beeps or see three flashes
1543 (“S” in Morse code for start up) and then a pause while
1544 the altimeter completes initialization and self test, and decides
1545 which mode to enter next.
1548 Here's a short summary of all of the modes and the beeping (or
1549 flashing, in the case of TeleMini v1) that accompanies each
1550 mode. In the description of the beeping pattern, “dit” means a
1551 short beep while "dah" means a long beep (three times as
1552 long). “Brap” means a long dissonant tone.
1554 <title>AltOS Modes</title>
1555 <?dbfo keep-together="always"?>
1556 <tgroup cols='4' align='center' colsep='1' rowsep='1'>
1557 <colspec align='center' colwidth='*' colname='Mode Name'/>
1558 <colspec align='center' colwidth='*' colname='Letter'/>
1559 <colspec align='center' colwidth='*' colname='Beeps'/>
1560 <colspec align='center' colwidth='*' colname='Description'/>
1563 <entry>Mode Name</entry>
1564 <entry>Abbreviation</entry>
1565 <entry>Beeps</entry>
1566 <entry>Description</entry>
1571 <entry>Startup</entry>
1573 <entry>dit dit dit</entry>
1576 Calibrating sensors, detecting orientation.
1583 <entry>dit dit</entry>
1586 Ready to accept commands over USB or radio link.
1593 <entry>dit dah dah dit</entry>
1596 Waiting for launch. Not listening for commands.
1601 <entry>Boost</entry>
1603 <entry>dah dit dit dit</entry>
1606 Accelerating upwards.
1613 <entry>dit dit dah dit</entry>
1616 Decelerating, but moving faster than 200m/s.
1621 <entry>Coast</entry>
1623 <entry>dah dit dah dit</entry>
1626 Decelerating, moving slower than 200m/s
1631 <entry>Drogue</entry>
1633 <entry>dah dit dit</entry>
1636 Descending after apogee. Above main height.
1643 <entry>dah dah</entry>
1646 Descending. Below main height.
1651 <entry>Landed</entry>
1653 <entry>dit dah dit dit</entry>
1656 Stable altitude for at least ten seconds.
1661 <entry>Sensor error</entry>
1663 <entry>dah dit dit dah</entry>
1666 Error detected during sensor calibration.
1675 In flight or “pad” mode, the altimeter engages the flight
1676 state machine, goes into transmit-only mode to send telemetry,
1677 and waits for launch to be detected. Flight mode is indicated
1678 by an “di-dah-dah-dit” (“P” for pad) on the beeper or lights,
1679 followed by beeps or flashes indicating the state of the
1680 pyrotechnic igniter continuity. One beep/flash indicates
1681 apogee continuity, two beeps/flashes indicate main continuity,
1682 three beeps/flashes indicate both apogee and main continuity,
1683 and one longer “brap” sound which is made by rapidly
1684 alternating between two tones indicates no continuity. For a
1685 dual deploy flight, make sure you're getting three beeps or
1686 flashes before launching! For apogee-only or motor eject
1687 flights, do what makes sense.
1690 If idle mode is entered, you will hear an audible “di-dit” or
1691 see two short flashes (“I” for idle), and the flight state
1692 machine is disengaged, thus no ejection charges will fire.
1693 The altimeters also listen for the radio link when in idle
1694 mode for requests sent via TeleDongle. Commands can be issued
1695 in idle mode over either USB or the radio link
1696 equivalently. TeleMini v1.0 only has the radio link. Idle
1697 mode is useful for configuring the altimeter, for extracting
1698 data from the on-board storage chip after flight, and for
1699 ground testing pyro charges.
1702 In “Idle” and “Pad” modes, once the mode indication
1703 beeps/flashes and continuity indication has been sent, if
1704 there is no space available to log the flight in on-board
1705 memory, the flight computer will emit a warbling tone (much
1706 slower than the “no continuity tone”)
1709 Here's a summary of all of the “pad” and “idle” mode indications.
1711 <title>Pad/Idle Indications</title>
1712 <?dbfo keep-together="always"?>
1713 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
1714 <colspec align='center' colwidth='*' colname='Name'/>
1715 <colspec align='center' colwidth='*' colname='Beeps'/>
1716 <colspec align='center' colwidth='*' colname='Description'/>
1720 <entry>Beeps</entry>
1721 <entry>Description</entry>
1726 <entry>Neither</entry>
1730 No continuity detected on either apogee or main
1736 <entry>Apogee</entry>
1740 Continuity detected only on apogee igniter.
1746 <entry>dit dit</entry>
1749 Continuity detected only on main igniter.
1755 <entry>dit dit dit</entry>
1758 Continuity detected on both igniters.
1763 <entry>Storage Full</entry>
1764 <entry>warble</entry>
1767 On-board data logging storage is full. This will
1768 not prevent the flight computer from safely
1769 controlling the flight or transmitting telemetry
1770 signals, but no record of the flight will be
1771 stored in on-board flash.
1780 Once landed, the flight computer will signal that by emitting
1781 the “Landed” sound described above, after which it will beep
1782 out the apogee height (in meters). Each digit is represented
1783 by a sequence of short “dit” beeps, with a pause between
1784 digits. A zero digit is represented with one long “dah”
1785 beep. The flight computer will continue to report landed mode
1786 and beep out the maximum height until turned off.
1789 One “neat trick” of particular value when TeleMetrum or TeleMega are used with
1790 very large air-frames, is that you can power the board up while the
1791 rocket is horizontal, such that it comes up in idle mode. Then you can
1792 raise the air-frame to launch position, and issue a 'reset' command
1793 via TeleDongle over the radio link to cause the altimeter to reboot and
1794 come up in flight mode. This is much safer than standing on the top
1795 step of a rickety step-ladder or hanging off the side of a launch
1796 tower with a screw-driver trying to turn on your avionics before
1797 installing igniters!
1800 TeleMini v1.0 is configured solely via the radio link. Of course, that
1801 means you need to know the TeleMini radio configuration values
1802 or you won't be able to communicate with it. For situations
1803 when you don't have the radio configuration values, TeleMini v1.0
1804 offers an 'emergency recovery' mode. In this mode, TeleMini is
1805 configured as follows:
1809 Sets the radio frequency to 434.550MHz
1814 Sets the radio calibration back to the factory value.
1819 Sets the callsign to N0CALL
1824 Does not go to 'pad' mode after five seconds.
1830 To get into 'emergency recovery' mode, first find the row of
1831 four small holes opposite the switch wiring. Using a short
1832 piece of small gauge wire, connect the outer two holes
1833 together, then power TeleMini up. Once the red LED is lit,
1834 disconnect the wire and the board should signal that it's in
1835 'idle' mode after the initial five second startup period.
1841 TeleMetrum and TeleMega include a complete GPS receiver. A
1842 complete explanation of how GPS works is beyond the scope of
1843 this manual, but the bottom line is that the GPS receiver
1844 needs to lock onto at least four satellites to obtain a solid
1845 3 dimensional position fix and know what time it is.
1848 The flight computers provide backup power to the GPS chip any time a
1849 battery is connected. This allows the receiver to “warm start” on
1850 the launch rail much faster than if every power-on were a GPS
1851 “cold start”. In typical operations, powering up
1852 on the flight line in idle mode while performing final air-frame
1853 preparation will be sufficient to allow the GPS receiver to cold
1854 start and acquire lock. Then the board can be powered down during
1855 RSO review and installation on a launch rod or rail. When the board
1856 is turned back on, the GPS system should lock very quickly, typically
1857 long before igniter installation and return to the flight line are
1862 <title>Controlling An Altimeter Over The Radio Link</title>
1864 One of the unique features of the Altus Metrum system is the
1865 ability to create a two way command link between TeleDongle
1866 and an altimeter using the digital radio transceivers
1867 built into each device. This allows you to interact with the
1868 altimeter from afar, as if it were directly connected to the
1872 Any operation which can be performed with a flight computer can
1873 either be done with the device directly connected to the
1874 computer via the USB cable, or through the radio
1875 link. TeleMini v1.0 doesn't provide a USB connector and so it is
1876 always communicated with over radio. Select the appropriate
1877 TeleDongle device when the list of devices is presented and
1878 AltosUI will interact with an altimeter over the radio link.
1881 One oddity in the current interface is how AltosUI selects the
1882 frequency for radio communications. Instead of providing
1883 an interface to specifically configure the frequency, it uses
1884 whatever frequency was most recently selected for the target
1885 TeleDongle device in Monitor Flight mode. If you haven't ever
1886 used that mode with the TeleDongle in question, select the
1887 Monitor Flight button from the top level UI, and pick the
1888 appropriate TeleDongle device. Once the flight monitoring
1889 window is open, select the desired frequency and then close it
1890 down again. All radio communications will now use that frequency.
1895 Save Flight Data—Recover flight data from the rocket without
1901 Configure altimeter apogee delays, main deploy heights
1902 and additional pyro event conditions
1903 to respond to changing launch conditions. You can also
1904 'reboot' the altimeter. Use this to remotely enable the
1905 flight computer by turning TeleMetrum or TeleMega on in “idle” mode,
1906 then once the air-frame is oriented for launch, you can
1907 reboot the altimeter and have it restart in pad mode
1908 without having to climb the scary ladder.
1913 Fire Igniters—Test your deployment charges without snaking
1914 wires out through holes in the air-frame. Simply assemble the
1915 rocket as if for flight with the apogee and main charges
1916 loaded, then remotely command the altimeter to fire the
1922 Operation over the radio link for configuring an altimeter, ground
1923 testing igniters, and so forth uses the same RF frequencies as flight
1924 telemetry. To configure the desired TeleDongle frequency, select
1925 the monitor flight tab, then use the frequency selector and
1926 close the window before performing other desired radio operations.
1929 The flight computers only enable radio commanding in 'idle' mode.
1930 TeleMetrum and TeleMega use the accelerometer to detect which orientation they
1931 start up in, so make sure you have the flight computer lying horizontally when you turn
1932 it on. Otherwise, it will start in 'pad' mode ready for
1933 flight, and will not be listening for command packets from TeleDongle.
1936 TeleMini listens for a command packet for five seconds after
1937 first being turned on, if it doesn't hear anything, it enters
1938 'pad' mode, ready for flight and will no longer listen for
1939 command packets. The easiest way to connect to TeleMini is to
1940 initiate the command and select the TeleDongle device. At this
1941 point, the TeleDongle will be attempting to communicate with
1942 the TeleMini. Now turn TeleMini on, and it should immediately
1943 start communicating with the TeleDongle and the desired
1944 operation can be performed.
1947 You can monitor the operation of the radio link by watching the
1948 lights on the devices. The red LED will flash each time a packet
1949 is transmitted, while the green LED will light up on TeleDongle when
1950 it is waiting to receive a packet from the altimeter.
1954 <title>Ground Testing </title>
1956 An important aspect of preparing a rocket using electronic deployment
1957 for flight is ground testing the recovery system. Thanks
1958 to the bi-directional radio link central to the Altus Metrum system,
1959 this can be accomplished in a TeleMega, TeleMetrum or TeleMini equipped rocket
1960 with less work than you may be accustomed to with other systems. It
1964 Just prep the rocket for flight, then power up the altimeter
1965 in “idle” mode (placing air-frame horizontal for TeleMetrum or TeleMega, or
1966 selecting the Configure Altimeter tab for TeleMini). This will cause
1967 the firmware to go into “idle” mode, in which the normal flight
1968 state machine is disabled and charges will not fire without
1969 manual command. You can now command the altimeter to fire the apogee
1970 or main charges from a safe distance using your computer and
1971 TeleDongle and the Fire Igniter tab to complete ejection testing.
1975 <title>Radio Link </title>
1977 Our flight computers all incorporate an RF transceiver, but
1978 it's not a full duplex system... each end can only be transmitting or
1979 receiving at any given moment. So we had to decide how to manage the
1983 By design, the altimeter firmware listens for the radio link when
1984 it's in “idle mode”, which
1985 allows us to use the radio link to configure the rocket, do things like
1986 ejection tests, and extract data after a flight without having to
1987 crack open the air-frame. However, when the board is in “flight
1988 mode”, the altimeter only
1989 transmits and doesn't listen at all. That's because we want to put
1990 ultimate priority on event detection and getting telemetry out of
1992 the radio in case the rocket crashes and we aren't able to extract
1996 We don't generally use a 'normal packet radio' mode like APRS
1997 because they're just too inefficient. The GFSK modulation we
1998 use is FSK with the base-band pulses passed through a Gaussian
1999 filter before they go into the modulator to limit the
2000 transmitted bandwidth. When combined with forward error
2001 correction and interleaving, this allows us to have a very
2002 robust 19.2 kilobit data link with only 10-40 milliwatts of
2003 transmit power, a whip antenna in the rocket, and a hand-held
2004 Yagi on the ground. We've had flights to above 21k feet AGL
2005 with great reception, and calculations suggest we should be
2006 good to well over 40k feet AGL with a 5-element yagi on the
2007 ground with our 10mW units and over 100k feet AGL with the
2008 40mW devices. We hope to fly boards to higher altitudes over
2009 time, and would of course appreciate customer feedback on
2010 performance in higher altitude flights!
2013 TeleMetrum v2.0 and TeleMega can send APRS if desired, and the
2014 interval between APRS packets can be configured. As each APRS
2015 packet takes a full second to transmit, we recommend an
2016 interval of at least 5 seconds to avoid consuming too much
2017 battery power or radio channel bandwidth.
2021 <title>Configurable Parameters</title>
2023 Configuring an Altus Metrum altimeter for flight is very
2024 simple. Even on our baro-only TeleMini and EasyMini boards, the use of a Kalman
2025 filter means there is no need to set a “mach delay”. The few
2026 configurable parameters can all be set using AltosUI over USB or
2027 or radio link via TeleDongle.
2030 <title>Radio Frequency</title>
2032 Altus Metrum boards support radio frequencies in the 70cm
2033 band. By default, the configuration interface provides a
2034 list of 10 “standard” frequencies in 100kHz channels starting at
2035 434.550MHz. However, the firmware supports use of
2036 any 50kHz multiple within the 70cm band. At any given
2037 launch, we highly recommend coordinating when and by whom each
2038 frequency will be used to avoid interference. And of course, both
2039 altimeter and TeleDongle must be configured to the same
2040 frequency to successfully communicate with each other.
2044 <title>Apogee Delay</title>
2046 Apogee delay is the number of seconds after the altimeter detects flight
2047 apogee that the drogue charge should be fired. In most cases, this
2048 should be left at the default of 0. However, if you are flying
2049 redundant electronics such as for an L3 certification, you may wish
2050 to set one of your altimeters to a positive delay so that both
2051 primary and backup pyrotechnic charges do not fire simultaneously.
2054 The Altus Metrum apogee detection algorithm fires exactly at
2055 apogee. If you are also flying an altimeter like the
2056 PerfectFlite MAWD, which only supports selecting 0 or 1
2057 seconds of apogee delay, you may wish to set the MAWD to 0
2058 seconds delay and set the TeleMetrum to fire your backup 2
2059 or 3 seconds later to avoid any chance of both charges
2060 firing simultaneously. We've flown several air-frames this
2061 way quite happily, including Keith's successful L3 cert.
2065 <title>Main Deployment Altitude</title>
2067 By default, the altimeter will fire the main deployment charge at an
2068 elevation of 250 meters (about 820 feet) above ground. We think this
2069 is a good elevation for most air-frames, but feel free to change this
2070 to suit. In particular, if you are flying two altimeters, you may
2072 deployment elevation for the backup altimeter to be something lower
2073 than the primary so that both pyrotechnic charges don't fire
2078 <title>Maximum Flight Log</title>
2080 Changing this value will set the maximum amount of flight
2081 log storage that an individual flight will use. The
2082 available storage is divided into as many flights of the
2083 specified size as can fit in the available space. You can
2084 download and erase individual flight logs. If you fill up
2085 the available storage, future flights will not get logged
2086 until you erase some of the stored ones.
2089 Even though our flight computers (except TeleMini v1.0) can store
2090 multiple flights, we strongly recommend downloading and saving
2091 flight data after each flight.
2095 <title>Ignite Mode</title>
2097 Instead of firing one charge at apogee and another charge at
2098 a fixed height above the ground, you can configure the
2099 altimeter to fire both at apogee or both during
2100 descent. This was added to support an airframe Bdale designed that
2101 had two altimeters, one in the fin can and one in the nose.
2104 Providing the ability to use both igniters for apogee or
2105 main allows some level of redundancy without needing two
2106 flight computers. In Redundant Apogee or Redundant Main
2107 mode, the two charges will be fired two seconds apart.
2111 <title>Pad Orientation</title>
2113 TeleMetrum and TeleMega measure acceleration along the axis
2114 of the board. Which way the board is oriented affects the
2115 sign of the acceleration value. Instead of trying to guess
2116 which way the board is mounted in the air frame, the
2117 altimeter must be explicitly configured for either Antenna
2118 Up or Antenna Down. The default, Antenna Up, expects the end
2119 of the board connected to the 70cm antenna to be nearest the
2120 nose of the rocket, with the end containing the screw
2121 terminals nearest the tail.
2125 <title>Configurable Pyro Channels</title>
2127 In addition to the usual Apogee and Main pyro channels,
2128 TeleMega has four additional channels that can be configured
2129 to activate when various flight conditions are
2130 satisfied. You can select as many conditions as necessary;
2131 all of them must be met in order to activate the
2132 channel. The conditions available are:
2137 Acceleration away from the ground. Select a value, and
2138 then choose whether acceleration should be above or
2139 below that value. Acceleration is positive upwards, so
2140 accelerating towards the ground would produce negative
2141 numbers. Acceleration during descent is noisy and
2142 inaccurate, so be careful when using it during these
2143 phases of the flight.
2148 Vertical speed. Select a value, and then choose whether
2149 vertical speed should be above or below that
2150 value. Speed is positive upwards, so moving towards the
2151 ground would produce negative numbers. Speed during
2152 descent is a bit noisy and so be careful when using it
2153 during these phases of the flight.
2158 Height. Select a value, and then choose whether the
2159 height above the launch pad should be above or below
2165 Orientation. TeleMega contains a 3-axis gyroscope and
2166 accelerometer which is used to measure the current
2167 angle. Note that this angle is not the change in angle
2168 from the launch pad, but rather absolute relative to
2169 gravity; the 3-axis accelerometer is used to compute the
2170 angle of the rocket on the launch pad and initialize the
2171 system. Because this value is computed by integrating
2172 rate gyros, it gets progressively less accurate as the
2173 flight goes on. It should have an accumulated error of
2174 less than 0.2°/second (after 10 seconds of flight, the
2175 error should be less than 2°).
2178 The usual use of the orientation configuration is to
2179 ensure that the rocket is traveling mostly upwards when
2180 deciding whether to ignite air starts or additional
2181 stages. For that, choose a reasonable maximum angle
2182 (like 20°) and set the motor igniter to require an angle
2183 of less than that value.
2188 Flight Time. Time since boost was detected. Select a
2189 value and choose whether to activate the pyro channel
2190 before or after that amount of time.
2195 Ascending. A simple test saying whether the rocket is
2196 going up or not. This is exactly equivalent to testing
2197 whether the speed is > 0.
2202 Descending. A simple test saying whether the rocket is
2203 going down or not. This is exactly equivalent to testing
2204 whether the speed is < 0.
2209 After Motor. The flight software counts each time the
2210 rocket starts accelerating (presumably due to a motor or
2211 motors igniting). Use this value to count ignitions for
2212 multi-staged or multi-airstart launches.
2217 Delay. This value doesn't perform any checks, instead it
2218 inserts a delay between the time when the other
2219 parameters become true and when the pyro channel is
2225 Flight State. The flight software tracks the flight
2226 through a sequence of states:
2230 Boost. The motor has lit and the rocket is
2231 accelerating upwards.
2236 Fast. The motor has burned out and the rocket is
2237 decelerating, but it is going faster than 200m/s.
2242 Coast. The rocket is still moving upwards and
2243 decelerating, but the speed is less than 200m/s.
2248 Drogue. The rocket has reached apogee and is heading
2249 back down, but is above the configured Main
2255 Main. The rocket is still descending, and is below
2261 Landed. The rocket is no longer moving.
2267 You can select a state to limit when the pyro channel
2268 may activate; note that the check is based on when the
2269 rocket transitions <emphasis>into</emphasis> the state, and so checking for
2270 “greater than Boost” means that the rocket is currently
2271 in boost or some later state.
2274 When a motor burns out, the rocket enters either Fast or
2275 Coast state (depending on how fast it is moving). If the
2276 computer detects upwards acceleration again, it will
2277 move back to Boost state.
2286 <title>AltosUI</title>
2290 <imagedata fileref="altosui.png" width="4.6in"/>
2295 The AltosUI program provides a graphical user interface for
2296 interacting with the Altus Metrum product family. AltosUI can
2297 monitor telemetry data, configure devices and many other
2298 tasks. The primary interface window provides a selection of
2299 buttons, one for each major activity in the system. This chapter
2300 is split into sections, each of which documents one of the tasks
2301 provided from the top-level toolbar.
2304 <title>Monitor Flight</title>
2305 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
2307 Selecting this item brings up a dialog box listing all of the
2308 connected TeleDongle devices. When you choose one of these,
2309 AltosUI will create a window to display telemetry data as
2310 received by the selected TeleDongle device.
2315 <imagedata fileref="device-selection.png" width="3.1in"/>
2320 All telemetry data received are automatically recorded in
2321 suitable log files. The name of the files includes the current
2322 date and rocket serial and flight numbers.
2325 The radio frequency being monitored by the TeleDongle device is
2326 displayed at the top of the window. You can configure the
2327 frequency by clicking on the frequency box and selecting the desired
2328 frequency. AltosUI remembers the last frequency selected for each
2329 TeleDongle and selects that automatically the next time you use
2333 Below the TeleDongle frequency selector, the window contains a few
2334 significant pieces of information about the altimeter providing
2335 the telemetry data stream:
2339 <para>The configured call-sign</para>
2342 <para>The device serial number</para>
2345 <para>The flight number. Each altimeter remembers how many
2351 The rocket flight state. Each flight passes through several
2352 states including Pad, Boost, Fast, Coast, Drogue, Main and
2358 The Received Signal Strength Indicator value. This lets
2359 you know how strong a signal TeleDongle is receiving. The
2360 radio inside TeleDongle operates down to about -99dBm;
2361 weaker signals may not be receivable. The packet link uses
2362 error detection and correction techniques which prevent
2363 incorrect data from being reported.
2368 The age of the displayed data, in seconds since the last
2369 successfully received telemetry packet. In normal operation
2370 this will stay in the low single digits. If the number starts
2371 counting up, then you are no longer receiving data over the radio
2372 link from the flight computer.
2377 Finally, the largest portion of the window contains a set of
2378 tabs, each of which contain some information about the rocket.
2379 They're arranged in 'flight order' so that as the flight
2380 progresses, the selected tab automatically switches to display
2381 data relevant to the current state of the flight. You can select
2382 other tabs at any time. The final 'table' tab displays all of
2383 the raw telemetry values in one place in a spreadsheet-like format.
2386 <title>Launch Pad</title>
2390 <imagedata fileref="launch-pad.png" width="5.5in"/>
2395 The 'Launch Pad' tab shows information used to decide when the
2396 rocket is ready for flight. The first elements include red/green
2397 indicators, if any of these is red, you'll want to evaluate
2398 whether the rocket is ready to launch:
2401 <term>Battery Voltage</term>
2404 This indicates whether the Li-Po battery powering the
2405 flight computer has sufficient charge to last for
2406 the duration of the flight. A value of more than
2407 3.8V is required for a 'GO' status.
2412 <term>Apogee Igniter Voltage</term>
2415 This indicates whether the apogee
2416 igniter has continuity. If the igniter has a low
2417 resistance, then the voltage measured here will be close
2418 to the Li-Po battery voltage. A value greater than 3.2V is
2419 required for a 'GO' status.
2424 <term>Main Igniter Voltage</term>
2427 This indicates whether the main
2428 igniter has continuity. If the igniter has a low
2429 resistance, then the voltage measured here will be close
2430 to the Li-Po battery voltage. A value greater than 3.2V is
2431 required for a 'GO' status.
2436 <term>On-board Data Logging</term>
2439 This indicates whether there is
2440 space remaining on-board to store flight data for the
2441 upcoming flight. If you've downloaded data, but failed
2442 to erase flights, there may not be any space
2443 left. Most of our flight computers can store multiple
2444 flights, depending on the configured maximum flight log
2445 size. TeleMini v1.0 stores only a single flight, so it
2447 downloaded and erased after each flight to capture
2448 data. This only affects on-board flight logging; the
2449 altimeter will still transmit telemetry and fire
2450 ejection charges at the proper times even if the flight
2451 data storage is full.
2456 <term>GPS Locked</term>
2459 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
2460 currently able to compute position information. GPS requires
2461 at least 4 satellites to compute an accurate position.
2466 <term>GPS Ready</term>
2469 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
2470 10 consecutive positions without losing lock. This ensures
2471 that the GPS receiver has reliable reception from the
2479 The Launchpad tab also shows the computed launch pad position
2480 and altitude, averaging many reported positions to improve the
2481 accuracy of the fix.
2485 <title>Ascent</title>
2489 <imagedata fileref="ascent.png" width="5.5in"/>
2494 This tab is shown during Boost, Fast and Coast
2495 phases. The information displayed here helps monitor the
2496 rocket as it heads towards apogee.
2499 The height, speed, acceleration and tilt are shown along
2500 with the maximum values for each of them. This allows you to
2501 quickly answer the most commonly asked questions you'll hear
2505 The current latitude and longitude reported by the GPS are
2506 also shown. Note that under high acceleration, these values
2507 may not get updated as the GPS receiver loses position
2508 fix. Once the rocket starts coasting, the receiver should
2509 start reporting position again.
2512 Finally, the current igniter voltages are reported as in the
2513 Launch Pad tab. This can help diagnose deployment failures
2514 caused by wiring which comes loose under high acceleration.
2518 <title>Descent</title>
2522 <imagedata fileref="descent.png" width="5.5in"/>
2527 Once the rocket has reached apogee and (we hope) activated the
2528 apogee charge, attention switches to tracking the rocket on
2529 the way back to the ground, and for dual-deploy flights,
2530 waiting for the main charge to fire.
2533 To monitor whether the apogee charge operated correctly, the
2534 current descent rate is reported along with the current
2535 height. Good descent rates vary based on the choice of recovery
2536 components, but generally range from 15-30m/s on drogue and should
2537 be below 10m/s when under the main parachute in a dual-deploy flight.
2540 With GPS-equipped flight computers, you can locate the rocket in the
2541 sky using the elevation and bearing information to figure
2542 out where to look. Elevation is in degrees above the
2543 horizon. Bearing is reported in degrees relative to true
2544 north. Range can help figure out how big the rocket will
2545 appear. Ground Distance shows how far it is to a point
2546 directly under the rocket and can help figure out where the
2547 rocket is likely to land. Note that all of these values are
2548 relative to the pad location. If the elevation is near 90°,
2549 the rocket is over the pad, not over you.
2552 Finally, the igniter voltages are reported in this tab as
2553 well, both to monitor the main charge as well as to see what
2554 the status of the apogee charge is. Note that some commercial
2555 e-matches are designed to retain continuity even after being
2556 fired, and will continue to show as green or return from red to
2561 <title>Landed</title>
2565 <imagedata fileref="landed.png" width="5.5in"/>
2570 Once the rocket is on the ground, attention switches to
2571 recovery. While the radio signal is often lost once the
2572 rocket is on the ground, the last reported GPS position is
2573 generally within a short distance of the actual landing location.
2576 The last reported GPS position is reported both by
2577 latitude and longitude as well as a bearing and distance from
2578 the launch pad. The distance should give you a good idea of
2579 whether to walk or hitch a ride. Take the reported
2580 latitude and longitude and enter them into your hand-held GPS
2581 unit and have that compute a track to the landing location.
2584 Our flight computers will continue to transmit RDF
2585 tones after landing, allowing you to locate the rocket by
2586 following the radio signal if necessary. You may need to get
2587 away from the clutter of the flight line, or even get up on
2588 a hill (or your neighbor's RV roof) to receive the RDF signal.
2591 The maximum height, speed and acceleration reported
2592 during the flight are displayed for your admiring observers.
2593 The accuracy of these immediate values depends on the quality
2594 of your radio link and how many packets were received.
2595 Recovering the on-board data after flight may yield
2596 more precise results.
2599 To get more detailed information about the flight, you can
2600 click on the 'Graph Flight' button which will bring up a
2601 graph window for the current flight.
2605 <title>Table</title>
2609 <imagedata fileref="table.png" width="5.5in"/>
2614 The table view shows all of the data available from the
2615 flight computer. Probably the most useful data on
2616 this tab is the detailed GPS information, which includes
2617 horizontal dilution of precision information, and
2618 information about the signal being received from the satellites.
2622 <title>Site Map</title>
2626 <imagedata fileref="site-map.png" width="5.5in"/>
2631 When the TeleMetrum has a GPS fix, the Site Map tab will map
2632 the rocket's position to make it easier for you to locate the
2633 rocket, both while it is in the air, and when it has landed. The
2634 rocket's state is indicated by color: white for pad, red for
2635 boost, pink for fast, yellow for coast, light blue for drogue,
2636 dark blue for main, and black for landed.
2639 The map's scale is approximately 3m (10ft) per pixel. The map
2640 can be dragged using the left mouse button. The map will attempt
2641 to keep the rocket roughly centered while data is being received.
2644 Images are fetched automatically via the Google Maps Static API,
2645 and cached on disk for reuse. If map images cannot be downloaded,
2646 the rocket's path will be traced on a dark gray background
2650 You can pre-load images for your favorite launch sites
2651 before you leave home; check out the 'Preload Maps' section below.
2656 <title>Save Flight Data</title>
2658 The altimeter records flight data to its internal flash memory.
2659 TeleMetrum data is recorded at a much higher rate than the telemetry
2660 system can handle, and is not subject to radio drop-outs. As
2661 such, it provides a more complete and precise record of the
2662 flight. The 'Save Flight Data' button allows you to read the
2663 flash memory and write it to disk.
2666 Clicking on the 'Save Flight Data' button brings up a list of
2667 connected flight computers and TeleDongle devices. If you select a
2668 flight computer, the flight data will be downloaded from that
2669 device directly. If you select a TeleDongle device, flight data
2670 will be downloaded from a flight computer over radio link via the
2671 specified TeleDongle. See the chapter on Controlling An Altimeter
2672 Over The Radio Link for more information.
2675 After the device has been selected, a dialog showing the
2676 flight data saved in the device will be shown allowing you to
2677 select which flights to download and which to delete. With
2678 version 0.9 or newer firmware, you must erase flights in order
2679 for the space they consume to be reused by another
2680 flight. This prevents accidentally losing flight data
2681 if you neglect to download data before flying again. Note that
2682 if there is no more space available in the device, then no
2683 data will be recorded during the next flight.
2686 The file name for each flight log is computed automatically
2687 from the recorded flight date, altimeter serial number and
2688 flight number information.
2692 <title>Replay Flight</title>
2694 Select this button and you are prompted to select a flight
2695 record file, either a .telem file recording telemetry data or a
2696 .eeprom file containing flight data saved from the altimeter
2700 Once a flight record is selected, the flight monitor interface
2701 is displayed and the flight is re-enacted in real time. Check
2702 the Monitor Flight chapter above to learn how this window operates.
2706 <title>Graph Data</title>
2708 Select this button and you are prompted to select a flight
2709 record file, either a .telem file recording telemetry data or a
2710 .eeprom file containing flight data saved from
2714 Note that telemetry files will generally produce poor graphs
2715 due to the lower sampling rate and missed telemetry packets.
2716 Use saved flight data in .eeprom files for graphing where possible.
2719 Once a flight record is selected, a window with multiple tabs is
2723 <title>Flight Graph</title>
2727 <imagedata fileref="graph.png" width="6in" scalefit="1"/>
2732 By default, the graph contains acceleration (blue),
2733 velocity (green) and altitude (red).
2736 The graph can be zoomed into a particular area by clicking and
2737 dragging down and to the right. Once zoomed, the graph can be
2738 reset by clicking and dragging up and to the left. Holding down
2739 control and clicking and dragging allows the graph to be panned.
2740 The right mouse button causes a pop-up menu to be displayed, giving
2741 you the option save or print the plot.
2745 <title>Configure Graph</title>
2749 <imagedata fileref="graph-configure.png" width="6in" scalefit="1"/>
2754 This selects which graph elements to show, and, at the
2755 very bottom, lets you switch between metric and
2760 <title>Flight Statistics</title>
2764 <imagedata fileref="graph-stats.png" width="6in" scalefit="1"/>
2769 Shows overall data computed from the flight.
2777 <imagedata fileref="graph-map.png" width="6in" scalefit="1"/>
2782 Shows a satellite image of the flight area overlaid
2783 with the path of the flight. The red concentric
2784 circles mark the launch pad, the black concentric
2785 circles mark the landing location.
2790 <title>Export Data</title>
2792 This tool takes the raw data files and makes them available for
2793 external analysis. When you select this button, you are prompted to
2794 select a flight data file, which can be either a .eeprom or .telem.
2795 The .eeprom files contain higher resolution and more continuous data,
2796 while .telem files contain receiver signal strength information.
2797 Next, a second dialog appears which is used to select
2798 where to write the resulting file. It has a selector to choose
2799 between CSV and KML file formats.
2802 <title>Comma Separated Value Format</title>
2804 This is a text file containing the data in a form suitable for
2805 import into a spreadsheet or other external data analysis
2806 tool. The first few lines of the file contain the version and
2807 configuration information from the altimeter, then
2808 there is a single header line which labels all of the
2809 fields. All of these lines start with a '#' character which
2810 many tools can be configured to skip over.
2813 The remaining lines of the file contain the data, with each
2814 field separated by a comma and at least one space. All of
2815 the sensor values are converted to standard units, with the
2816 barometric data reported in both pressure, altitude and
2817 height above pad units.
2821 <title>Keyhole Markup Language (for Google Earth)</title>
2823 This is the format used by Google Earth to provide an overlay
2824 within that application. With this, you can use Google Earth to
2825 see the whole flight path in 3D.
2830 <title>Configure Altimeter</title>
2834 <imagedata fileref="configure-altimeter.png" width="3.6in" scalefit="1"/>
2839 Select this button and then select either an altimeter or
2840 TeleDongle Device from the list provided. Selecting a TeleDongle
2841 device will use the radio link to configure a remote altimeter.
2844 The first few lines of the dialog provide information about the
2845 connected device, including the product name,
2846 software version and hardware serial number. Below that are the
2847 individual configuration entries.
2850 At the bottom of the dialog, there are four buttons:
2857 This writes any changes to the
2858 configuration parameter block in flash memory. If you don't
2859 press this button, any changes you make will be lost.
2867 This resets the dialog to the most recently saved values,
2868 erasing any changes you have made.
2876 This reboots the device. Use this to
2877 switch from idle to pad mode by rebooting once the rocket is
2878 oriented for flight, or to confirm changes you think you saved
2887 This closes the dialog. Any unsaved changes will be
2894 The rest of the dialog contains the parameters to be configured.
2897 <title>Main Deploy Altitude</title>
2899 This sets the altitude (above the recorded pad altitude) at
2900 which the 'main' igniter will fire. The drop-down menu shows
2901 some common values, but you can edit the text directly and
2902 choose whatever you like. If the apogee charge fires below
2903 this altitude, then the main charge will fire two seconds
2904 after the apogee charge fires.
2908 <title>Apogee Delay</title>
2910 When flying redundant electronics, it's often important to
2911 ensure that multiple apogee charges don't fire at precisely
2912 the same time, as that can over pressurize the apogee deployment
2913 bay and cause a structural failure of the air-frame. The Apogee
2914 Delay parameter tells the flight computer to fire the apogee
2915 charge a certain number of seconds after apogee has been
2920 <title>Radio Frequency</title>
2922 This configures which of the frequencies to use for both
2923 telemetry and packet command mode. Note that if you set this
2924 value via packet command mode, the TeleDongle frequency will
2925 also be automatically reconfigured to match so that
2926 communication will continue afterwards.
2930 <title>RF Calibration</title>
2932 The radios in every Altus Metrum device are calibrated at the
2933 factory to ensure that they transmit and receive on the
2934 specified frequency. If you need to you can adjust the calibration
2935 by changing this value. Do not do this without understanding what
2936 the value means, read the appendix on calibration and/or the source
2937 code for more information. To change a TeleDongle's calibration,
2938 you must reprogram the unit completely.
2942 <title>Telemetry/RDF/APRS Enable</title>
2944 Enables the radio for transmission during flight. When
2945 disabled, the radio will not transmit anything during flight
2950 <title>APRS Interval</title>
2952 How often to transmit GPS information via APRS (in
2953 seconds). When set to zero, APRS transmission is
2954 disabled. This option is available on TeleMetrum v2 and
2955 TeleMega boards. TeleMetrum v1 boards cannot transmit APRS
2956 packets. Note that a single APRS packet takes nearly a full
2957 second to transmit, so enabling this option will prevent
2958 sending any other telemetry during that time.
2962 <title>Callsign</title>
2964 This sets the call sign included in each telemetry packet. Set this
2965 as needed to conform to your local radio regulations.
2969 <title>Maximum Flight Log Size</title>
2971 This sets the space (in kilobytes) allocated for each flight
2972 log. The available space will be divided into chunks of this
2973 size. A smaller value will allow more flights to be stored,
2974 a larger value will record data from longer flights.
2978 <title>Ignite Mode</title>
2980 TeleMetrum and TeleMini provide two igniter channels as they
2981 were originally designed as dual-deploy flight
2982 computers. This configuration parameter allows the two
2983 channels to be used in different configurations.
2987 <term>Dual Deploy</term>
2990 This is the usual mode of operation; the
2991 'apogee' channel is fired at apogee and the 'main'
2992 channel at the height above ground specified by the
2993 'Main Deploy Altitude' during descent.
2998 <term>Redundant Apogee</term>
3001 This fires both channels at
3002 apogee, the 'apogee' channel first followed after a two second
3003 delay by the 'main' channel.
3008 <term>Redundant Main</term>
3011 This fires both channels at the
3012 height above ground specified by the Main Deploy
3013 Altitude setting during descent. The 'apogee'
3014 channel is fired first, followed after a two second
3015 delay by the 'main' channel.
3022 <title>Pad Orientation</title>
3024 Because they include accelerometers, TeleMetrum and
3025 TeleMega are sensitive to the orientation of the board. By
3026 default, they expect the antenna end to point forward. This
3027 parameter allows that default to be changed, permitting the
3028 board to be mounted with the antenna pointing aft instead.
3032 <term>Antenna Up</term>
3035 In this mode, the antenna end of the
3036 flight computer must point forward, in line with the
3037 expected flight path.
3042 <term>Antenna Down</term>
3045 In this mode, the antenna end of the
3046 flight computer must point aft, in line with the
3047 expected flight path.
3054 <title>Configure Pyro Channels</title>
3058 <imagedata fileref="configure-pyro.png" width="6in" scalefit="1"/>
3063 This opens a separate window to configure the additional
3064 pyro channels available on TeleMega. One column is
3065 presented for each channel. Each row represents a single
3066 parameter, if enabled the parameter must meet the specified
3067 test for the pyro channel to be fired. See the Pyro Channels
3068 section in the System Operation chapter above for a
3069 description of these parameters.
3072 Select conditions and set the related value; the pyro
3073 channel will be activated when <emphasis>all</emphasis> of the
3074 conditions are met. Each pyro channel has a separate set of
3075 configuration values, so you can use different values for
3076 the same condition with different channels.
3079 Once you have selected the appropriate configuration for all
3080 of the necessary pyro channels, you can save the pyro
3081 configuration along with the rest of the flight computer
3082 configuration by pressing the 'Save' button in the main
3083 Configure Flight Computer window.
3088 <title>Configure AltosUI</title>
3092 <imagedata fileref="configure-altosui.png" width="2.4in" scalefit="1"/>
3097 This button presents a dialog so that you can configure the AltosUI global settings.
3100 <title>Voice Settings</title>
3102 AltosUI provides voice announcements during flight so that you
3103 can keep your eyes on the sky and still get information about
3104 the current flight status. However, sometimes you don't want
3111 <para>Turns all voice announcements on and off</para>
3115 <term>Test Voice</term>
3118 Plays a short message allowing you to verify
3119 that the audio system is working and the volume settings
3127 <title>Log Directory</title>
3129 AltosUI logs all telemetry data and saves all TeleMetrum flash
3130 data to this directory. This directory is also used as the
3131 staring point when selecting data files for display or export.
3134 Click on the directory name to bring up a directory choosing
3135 dialog, select a new directory and click 'Select Directory' to
3136 change where AltosUI reads and writes data files.
3140 <title>Callsign</title>
3142 This value is transmitted in each command packet sent from
3143 TeleDongle and received from an altimeter. It is not used in
3144 telemetry mode, as the callsign configured in the altimeter board
3145 is included in all telemetry packets. Configure this
3146 with the AltosUI operators call sign as needed to comply with
3147 your local radio regulations.
3150 Note that to successfully command a flight computer over the radio
3151 (to configure the altimeter, monitor idle, or fire pyro charges),
3152 the callsign configured here must exactly match the callsign
3153 configured in the flight computer. This matching is case
3158 <title>Imperial Units</title>
3160 This switches between metric units (meters) and imperial
3161 units (feet and miles). This affects the display of values
3162 use during flight monitoring, configuration, data graphing
3163 and all of the voice announcements. It does not change the
3164 units used when exporting to CSV files, those are always
3165 produced in metric units.
3169 <title>Font Size</title>
3171 Selects the set of fonts used in the flight monitor
3172 window. Choose between the small, medium and large sets.
3176 <title>Serial Debug</title>
3178 This causes all communication with a connected device to be
3179 dumped to the console from which AltosUI was started. If
3180 you've started it from an icon or menu entry, the output
3181 will simply be discarded. This mode can be useful to debug
3182 various serial communication issues.
3186 <title>Manage Frequencies</title>
3188 This brings up a dialog where you can configure the set of
3189 frequencies shown in the various frequency menus. You can
3190 add as many as you like, or even reconfigure the default
3191 set. Changing this list does not affect the frequency
3192 settings of any devices, it only changes the set of
3193 frequencies shown in the menus.
3198 <title>Configure Groundstation</title>
3202 <imagedata fileref="configure-groundstation.png" width="3.1in" scalefit="1"/>
3207 Select this button and then select a TeleDongle Device from the list provided.
3210 The first few lines of the dialog provide information about the
3211 connected device, including the product name,
3212 software version and hardware serial number. Below that are the
3213 individual configuration entries.
3216 Note that the TeleDongle itself doesn't save any configuration
3217 data, the settings here are recorded on the local machine in
3218 the Java preferences database. Moving the TeleDongle to
3219 another machine, or using a different user account on the same
3220 machine will cause settings made here to have no effect.
3223 At the bottom of the dialog, there are three buttons:
3230 This writes any changes to the
3231 local Java preferences file. If you don't
3232 press this button, any changes you make will be lost.
3240 This resets the dialog to the most recently saved values,
3241 erasing any changes you have made.
3249 This closes the dialog. Any unsaved changes will be
3256 The rest of the dialog contains the parameters to be configured.
3259 <title>Frequency</title>
3261 This configures the frequency to use for both telemetry and
3262 packet command mode. Set this before starting any operation
3263 involving packet command mode so that it will use the right
3264 frequency. Telemetry monitoring mode also provides a menu to
3265 change the frequency, and that menu also sets the same Java
3266 preference value used here.
3270 <title>Radio Calibration</title>
3272 The radios in every Altus Metrum device are calibrated at the
3273 factory to ensure that they transmit and receive on the
3274 specified frequency. To change a TeleDongle's calibration,
3275 you must reprogram the unit completely, so this entry simply
3276 shows the current value and doesn't allow any changes.
3281 <title>Flash Image</title>
3283 This reprograms Altus Metrum devices with new
3284 firmware. TeleMetrum v1.x, TeleDongle, TeleMini and TeleBT are
3285 all reprogrammed by using another similar unit as a
3286 programming dongle (pair programming). TeleMega, TeleMetrum v2
3287 and EasyMini are all programmed directly over their USB ports
3288 (self programming). Please read the directions for flashing
3289 devices in the Updating Device Firmware chapter below.
3293 <title>Fire Igniter</title>
3297 <imagedata fileref="fire-igniter.png" width="1.2in" scalefit="1"/>
3302 This activates the igniter circuits in the flight computer to help
3303 test recovery systems deployment. Because this command can operate
3304 over the Packet Command Link, you can prepare the rocket as
3305 for flight and then test the recovery system without needing
3306 to snake wires inside the air-frame.
3309 Selecting the 'Fire Igniter' button brings up the usual device
3310 selection dialog. Pick the desired device. This brings up another
3311 window which shows the current continuity test status for all
3312 of the pyro channels.
3315 Next, select the desired igniter to fire. This will enable the
3319 Select the 'Arm' button. This enables the 'Fire' button. The
3320 word 'Arm' is replaced by a countdown timer indicating that
3321 you have 10 seconds to press the 'Fire' button or the system
3322 will deactivate, at which point you start over again at
3323 selecting the desired igniter.
3327 <title>Scan Channels</title>
3331 <imagedata fileref="scan-channels.png" width="3.2in" scalefit="1"/>
3336 This listens for telemetry packets on all of the configured
3337 frequencies, displaying information about each device it
3338 receives a packet from. You can select which of the three
3339 telemetry formats should be tried; by default, it only listens
3340 for the standard telemetry packets used in v1.0 and later
3345 <title>Load Maps</title>
3349 <imagedata fileref="load-maps.png" width="5.2in" scalefit="1"/>
3354 Before heading out to a new launch site, you can use this to
3355 load satellite images in case you don't have internet
3356 connectivity at the site. This loads a fairly large area
3357 around the launch site, which should cover any flight you're likely to make.
3360 There's a drop-down menu of launch sites we know about; if
3361 your favorites aren't there, please let us know the lat/lon
3362 and name of the site. The contents of this list are actually
3363 downloaded from our server at run-time, so as new sites are sent
3364 in, they'll get automatically added to this list.
3367 If the launch site isn't in the list, you can manually enter the lat/lon values
3370 Clicking the 'Load Map' button will fetch images from Google
3371 Maps; note that Google limits how many images you can fetch at
3372 once, so if you load more than one launch site, you may get
3373 some gray areas in the map which indicate that Google is tired
3374 of sending data to you. Try again later.
3378 <title>Monitor Idle</title>
3380 This brings up a dialog similar to the Monitor Flight UI,
3381 except it works with the altimeter in “idle” mode by sending
3382 query commands to discover the current state rather than
3383 listening for telemetry packets. Because this uses command
3384 mode, it needs to have the TeleDongle and flight computer
3385 callsigns match exactly. If you can receive telemetry, but
3386 cannot manage to run Monitor Idle, then it's very likely that
3387 your callsigns are different in some way.
3392 <title>AltosDroid</title>
3394 AltosDroid provides the same flight monitoring capabilities as
3395 AltosUI, but runs on Android devices and is designed to connect
3396 to a TeleBT receiver over Bluetooth™. AltosDroid monitors
3397 telemetry data, logging it to internal storage in the Android
3398 device, and presents that data in a UI the same way the 'Monitor
3399 Flight' window does in AltosUI.
3402 This manual will explain how to configure AltosDroid, connect
3403 to TeleBT, operate the flight monitoring interface and describe
3404 what the displayed data means.
3407 <title>Installing AltosDroid</title>
3409 AltosDroid is available from the Google Play store. To install
3410 it on your Android device, open the Google Play Store
3411 application and search for “altosdroid”. Make sure you don't
3412 have a space between “altos” and “droid” or you probably won't
3413 find what you want. That should bring you to the right page
3414 from which you can download and install the application.
3418 <title>Connecting to TeleBT</title>
3420 Press the Android 'Menu' button or soft-key to see the
3421 configuration options available. Select the 'Connect a device'
3422 option and then the 'Scan for devices' entry at the bottom to
3423 look for your TeleBT device. Select your device, and when it
3424 asks for the code, enter '1234'.
3427 Subsequent connections will not require you to enter that
3428 code, and your 'paired' device will appear in the list without
3433 <title>Configuring AltosDroid</title>
3435 The only configuration option available for AltosDroid is
3436 which frequency to listen on. Press the Android 'Menu' button
3437 or soft-key and pick the 'Select radio frequency' entry. That
3438 brings up a menu of pre-set radio frequencies; pick the one
3439 which matches your altimeter.
3443 <title>AltosDroid Flight Monitoring</title>
3445 AltosDroid is designed to mimic the AltosUI flight monitoring
3446 display, providing separate tabs for each stage of your rocket
3447 flight along with a tab containing a map of the local area
3448 with icons marking the current location of the altimeter and
3454 The 'Launch Pad' tab shows information used to decide when the
3455 rocket is ready for flight. The first elements include red/green
3456 indicators, if any of these is red, you'll want to evaluate
3457 whether the rocket is ready to launch:
3460 <term>Battery Voltage</term>
3463 This indicates whether the Li-Po battery
3464 powering the TeleMetrum has sufficient charge to last for
3465 the duration of the flight. A value of more than
3466 3.8V is required for a 'GO' status.
3471 <term>Apogee Igniter Voltage</term>
3474 This indicates whether the apogee
3475 igniter has continuity. If the igniter has a low
3476 resistance, then the voltage measured here will be close
3477 to the Li-Po battery voltage. A value greater than 3.2V is
3478 required for a 'GO' status.
3483 <term>Main Igniter Voltage</term>
3486 This indicates whether the main
3487 igniter has continuity. If the igniter has a low
3488 resistance, then the voltage measured here will be close
3489 to the Li-Po battery voltage. A value greater than 3.2V is
3490 required for a 'GO' status.
3495 <term>On-board Data Logging</term>
3498 This indicates whether there is
3499 space remaining on-board to store flight data for the
3500 upcoming flight. If you've downloaded data, but failed
3501 to erase flights, there may not be any space
3502 left. TeleMetrum can store multiple flights, depending
3503 on the configured maximum flight log size. TeleMini
3504 stores only a single flight, so it will need to be
3505 downloaded and erased after each flight to capture
3506 data. This only affects on-board flight logging; the
3507 altimeter will still transmit telemetry and fire
3508 ejection charges at the proper times.
3513 <term>GPS Locked</term>
3516 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
3517 currently able to compute position information. GPS requires
3518 at least 4 satellites to compute an accurate position.
3523 <term>GPS Ready</term>
3526 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
3527 10 consecutive positions without losing lock. This ensures
3528 that the GPS receiver has reliable reception from the
3536 The Launchpad tab also shows the computed launch pad position
3537 and altitude, averaging many reported positions to improve the
3538 accuracy of the fix.
3543 <title>Downloading Flight Logs</title>
3545 AltosDroid always saves every bit of telemetry data it
3546 receives. To download that to a computer for use with AltosUI,
3547 simply remove the SD card from your Android device, or connect
3548 your device to your computer's USB port and browse the files
3549 on that device. You will find '.telem' files in the TeleMetrum
3550 directory that will work with AltosUI directly.
3555 <title>Using Altus Metrum Products</title>
3557 <title>Being Legal</title>
3559 First off, in the US, you need an <ulink url="http://www.altusmetrum.org/Radio/">amateur radio license</ulink> or
3560 other authorization to legally operate the radio transmitters that are part
3565 <title>In the Rocket</title>
3567 In the rocket itself, you just need a flight computer and
3568 a single-cell, 3.7 volt nominal Li-Po rechargeable battery. An
3569 850mAh battery weighs less than a 9V alkaline battery, and will
3570 run a TeleMetrum or TeleMega for hours.
3571 A 110mAh battery weighs less than a triple A battery and is a good
3572 choice for use with TeleMini.
3575 By default, we ship flight computers with a simple wire antenna.
3576 If your electronics bay or the air-frame it resides within is made
3577 of carbon fiber, which is opaque to RF signals, you may prefer to
3578 install an SMA connector so that you can run a coaxial cable to an
3579 antenna mounted elsewhere in the rocket. However, note that the
3580 GPS antenna is fixed on all current products, so you really want
3581 to install the flight computer in a bay made of RF-transparent
3582 materials if at all possible.
3586 <title>On the Ground</title>
3588 To receive the data stream from the rocket, you need an antenna and short
3589 feed-line connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. If possible, use an SMA to BNC
3590 adapter instead of feedline between the antenna feedpoint and
3591 TeleDongle, as this will give you the best performance. The
3592 TeleDongle in turn plugs directly into the USB port on a notebook
3593 computer. Because TeleDongle looks like a simple serial port, your computer
3594 does not require special device drivers... just plug it in.
3597 The GUI tool, AltosUI, is written in Java and runs across
3598 Linux, Mac OS and Windows. There's also a suite of C tools
3599 for Linux which can perform most of the same tasks.
3602 Alternatively, a TeleBT attached with an SMA to BNC adapter at the
3603 feed point of a hand-held yagi used in conjunction with an Android
3604 device running AltosDroid makes an outstanding ground station.
3607 After the flight, you can use the radio link to extract the more detailed data
3608 logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
3609 TeleMetrum board directly. Pulling out the data without having to open up
3610 the rocket is pretty cool! A USB cable is also how you charge the Li-Po
3611 battery, so you'll want one of those anyway... the same cable used by lots
3612 of digital cameras and other modern electronic stuff will work fine.
3615 If your rocket lands out of sight, you may enjoy having a hand-held
3616 GPS receiver, so that you can put in a way-point for the last
3617 reported rocket position before touch-down. This makes looking for
3618 your rocket a lot like Geo-Caching... just go to the way-point and
3619 look around starting from there. AltosDroid on an Android device
3620 with GPS receiver works great for this, too!
3623 You may also enjoy having a ham radio “HT” that covers the 70cm band... you
3624 can use that with your antenna to direction-find the rocket on the ground
3625 the same way you can use a Walston or Beeline tracker. This can be handy
3626 if the rocket is hiding in sage brush or a tree, or if the last GPS position
3627 doesn't get you close enough because the rocket dropped into a canyon, or
3628 the wind is blowing it across a dry lake bed, or something like that... Keith
3629 currently uses a Yaesu VX-7R, Bdale has a Baofung UV-5R
3630 which isn't as nice, but was a whole lot cheaper.
3633 So, to recap, on the ground the hardware you'll need includes:
3634 <orderedlist inheritnum='inherit' numeration='arabic'>
3637 an antenna and feed-line or adapter
3652 optionally, a hand-held GPS receiver
3657 optionally, an HT or receiver covering 435 MHz
3663 The best hand-held commercial directional antennas we've found for radio
3664 direction finding rockets are from
3665 <ulink url="http://www.arrowantennas.com/" >
3668 The 440-3 and 440-5 are both good choices for finding a
3669 TeleMetrum- or TeleMini- equipped rocket when used with a suitable
3670 70cm HT. TeleDongle and an SMA to BNC adapter fit perfectly
3671 between the driven element and reflector of Arrow antennas.
3675 <title>Data Analysis</title>
3677 Our software makes it easy to log the data from each flight, both the
3678 telemetry received during the flight itself, and the more
3679 complete data log recorded in the flash memory on the altimeter
3680 board. Once this data is on your computer, our post-flight tools make it
3681 easy to quickly get to the numbers everyone wants, like apogee altitude,
3682 max acceleration, and max velocity. You can also generate and view a
3683 standard set of plots showing the altitude, acceleration, and
3684 velocity of the rocket during flight. And you can even export a TeleMetrum data file
3685 usable with Google Maps and Google Earth for visualizing the flight path
3686 in two or three dimensions!
3689 Our ultimate goal is to emit a set of files for each flight that can be
3690 published as a web page per flight, or just viewed on your local disk with
3695 <title>Future Plans</title>
3697 We've designed a simple GPS based radio tracker called TeleGPS.
3698 If all goes well, we hope to introduce this in the first
3702 We have designed and prototyped several “companion boards” that
3703 can attach to the companion connector on TeleMetrum and TeleMega
3704 flight computers to collect more data, provide more pyro channels,
3705 and so forth. We do not yet know if or when any of these boards
3706 will be produced in enough quantity to sell. If you have specific
3707 interests for data collection or control of events in your rockets
3708 beyond the capabilities of our existing productions, please let
3712 Because all of our work is open, both the hardware designs and the
3713 software, if you have some great idea for an addition to the current
3714 Altus Metrum family, feel free to dive in and help! Or let us know
3715 what you'd like to see that we aren't already working on, and maybe
3716 we'll get excited about it too...
3720 <ulink url="http://altusmetrum.org/">web site</ulink> for more news
3721 and information as our family of products evolves!
3726 <title>Altimeter Installation Recommendations</title>
3728 Building high-power rockets that fly safely is hard enough. Mix
3729 in some sophisticated electronics and a bunch of radio energy
3730 and some creativity and/or compromise may be required. This chapter
3731 contains some suggestions about how to install Altus Metrum
3732 products into a rocket air-frame, including how to safely and
3733 reliably mix a variety of electronics into the same air-frame.
3736 <title>Mounting the Altimeter</title>
3738 The first consideration is to ensure that the altimeter is
3739 securely fastened to the air-frame. For most of our products, we
3740 prefer nylon standoffs and nylon screws; they're good to at least 50G
3741 and cannot cause any electrical issues on the board. Metal screws
3742 and standoffs are fine, too, just be careful to avoid electrical
3743 shorts! For TeleMini v1.0, we usually cut small pieces of 1/16 inch
3745 under the screw holes, and then take 2x56 nylon screws and
3746 screw them through the TeleMini mounting holes, through the
3747 balsa and into the underlying material.
3749 <orderedlist inheritnum='inherit' numeration='arabic'>
3752 Make sure accelerometer-equipped products like TeleMetrum and
3753 TeleMega are aligned precisely along the axis of
3754 acceleration so that the accelerometer can accurately
3755 capture data during the flight.
3760 Watch for any metal touching components on the
3761 board. Shorting out connections on the bottom of the board
3762 can cause the altimeter to fail during flight.
3768 <title>Dealing with the Antenna</title>
3770 The antenna supplied is just a piece of solid, insulated,
3771 wire. If it gets damaged or broken, it can be easily
3772 replaced. It should be kept straight and not cut; bending or
3773 cutting it will change the resonant frequency and/or
3774 impedance, making it a less efficient radiator and thus
3775 reducing the range of the telemetry signal.
3778 Keeping metal away from the antenna will provide better range
3779 and a more even radiation pattern. In most rockets, it's not
3780 entirely possible to isolate the antenna from metal
3781 components; there are often bolts, all-thread and wires from other
3782 electronics to contend with. Just be aware that the more stuff
3783 like this around the antenna, the lower the range.
3786 Make sure the antenna is not inside a tube made or covered
3787 with conducting material. Carbon fiber is the most common
3788 culprit here -- CF is a good conductor and will effectively
3789 shield the antenna, dramatically reducing signal strength and
3790 range. Metallic flake paint is another effective shielding
3791 material which should be avoided around any antennas.
3794 If the ebay is large enough, it can be convenient to simply
3795 mount the altimeter at one end and stretch the antenna out
3796 inside. Taping the antenna to the sled can keep it straight
3797 under acceleration. If there are metal rods, keep the
3798 antenna as far away as possible.
3801 For a shorter ebay, it's quite practical to have the antenna
3802 run through a bulkhead and into an adjacent bay. Drill a small
3803 hole in the bulkhead, pass the antenna wire through it and
3804 then seal it up with glue or clay. We've also used acrylic
3805 tubing to create a cavity for the antenna wire. This works a
3806 bit better in that the antenna is known to stay straight and
3807 not get folded by recovery components in the bay. Angle the
3808 tubing towards the side wall of the rocket and it ends up
3809 consuming very little space.
3812 If you need to place the UHF antenna at a distance from the
3813 altimeter, you can replace the antenna with an edge-mounted
3814 SMA connector, and then run 50Ω coax from the board to the
3815 antenna. Building a remote antenna is beyond the scope of this
3820 <title>Preserving GPS Reception</title>
3822 The GPS antenna and receiver used in TeleMetrum and TeleMega is
3823 highly sensitive and normally have no trouble tracking enough
3824 satellites to provide accurate position information for
3825 recovering the rocket. However, there are many ways the GPS signal
3826 can end up attenuated, negatively affecting GPS performance.
3827 <orderedlist inheritnum='inherit' numeration='arabic'>
3830 Conductive tubing or coatings. Carbon fiber and metal
3831 tubing, or metallic paint will all dramatically attenuate the
3832 GPS signal. We've never heard of anyone successfully
3833 receiving GPS from inside these materials.
3838 Metal components near the GPS patch antenna. These will
3839 de-tune the patch antenna, changing the resonant frequency
3840 away from the L1 carrier and reduce the effectiveness of the
3841 antenna. You can place as much stuff as you like beneath the
3842 antenna as that's covered with a ground plane. But, keep
3843 wires and metal out from above the patch antenna.
3850 <title>Radio Frequency Interference</title>
3852 Any altimeter will generate RFI; the digital circuits use
3853 high-frequency clocks that spray radio interference across a
3854 wide band. Altus Metrum altimeters generate intentional radio
3855 signals as well, increasing the amount of RF energy around the board.
3858 Rocketry altimeters also use precise sensors measuring air
3859 pressure and acceleration. Tiny changes in voltage can cause
3860 these sensor readings to vary by a huge amount. When the
3861 sensors start mis-reporting data, the altimeter can either
3862 fire the igniters at the wrong time, or not fire them at all.
3865 Voltages are induced when radio frequency energy is
3866 transmitted from one circuit to another. Here are things that
3867 influence the induced voltage and current:
3872 Keep wires from different circuits apart. Moving circuits
3873 further apart will reduce RFI.
3878 Avoid parallel wires from different circuits. The longer two
3879 wires run parallel to one another, the larger the amount of
3880 transferred energy. Cross wires at right angles to reduce
3886 Twist wires from the same circuits. Two wires the same
3887 distance from the transmitter will get the same amount of
3888 induced energy which will then cancel out. Any time you have
3889 a wire pair running together, twist the pair together to
3890 even out distances and reduce RFI. For altimeters, this
3891 includes battery leads, switch hookups and igniter
3897 Avoid resonant lengths. Know what frequencies are present
3898 in the environment and avoid having wire lengths near a
3899 natural resonant length. Altus Metrum products transmit on the
3900 70cm amateur band, so you should avoid lengths that are a
3901 simple ratio of that length; essentially any multiple of ¼
3902 of the wavelength (17.5cm).
3908 <title>The Barometric Sensor</title>
3910 Altusmetrum altimeters measure altitude with a barometric
3911 sensor, essentially measuring the amount of air above the
3912 rocket to figure out how high it is. A large number of
3913 measurements are taken as the altimeter initializes itself to
3914 figure out the pad altitude. Subsequent measurements are then
3915 used to compute the height above the pad.
3918 To accurately measure atmospheric pressure, the ebay
3919 containing the altimeter must be vented outside the
3920 air-frame. The vent must be placed in a region of linear
3921 airflow, have smooth edges, and away from areas of increasing or
3922 decreasing pressure.
3925 All barometric sensors are quite sensitive to chemical damage from
3926 the products of APCP or BP combustion, so make sure the ebay is
3927 carefully sealed from any compartment which contains ejection
3932 <title>Ground Testing</title>
3934 The most important aspect of any installation is careful
3935 ground testing. Bringing an air-frame up to the LCO table which
3936 hasn't been ground tested can lead to delays or ejection
3937 charges firing on the pad, or, even worse, a recovery system
3941 Do a 'full systems' test that includes wiring up all igniters
3942 without any BP and turning on all of the electronics in flight
3943 mode. This will catch any mistakes in wiring and any residual
3944 RFI issues that might accidentally fire igniters at the wrong
3945 time. Let the air-frame sit for several minutes, checking for
3946 adequate telemetry signal strength and GPS lock. If any igniters
3947 fire unexpectedly, find and resolve the issue before loading any
3951 Ground test the ejection charges. Prepare the rocket for
3952 flight, loading ejection charges and igniters. Completely
3953 assemble the air-frame and then use the 'Fire Igniters'
3954 interface through a TeleDongle to command each charge to
3955 fire. Make sure the charge is sufficient to robustly separate
3956 the air-frame and deploy the recovery system.
3961 <title>Updating Device Firmware</title>
3963 TeleMega, TeleMetrum v2 and EasyMini are all programmed directly
3964 over their USB connectors (self programming). TeleMetrum v1, TeleMini and
3965 TeleDongle are all programmed by using another device as a
3966 programmer (pair programming). It's important to recognize which
3967 kind of devices you have before trying to reprogram them.
3970 You may wish to begin by ensuring you have current firmware images.
3971 These are distributed as part of the AltOS software bundle that
3972 also includes the AltosUI ground station program. Newer ground
3973 station versions typically work fine with older firmware versions,
3974 so you don't need to update your devices just to try out new
3975 software features. You can always download the most recent
3976 version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
3979 If you need to update the firmware on a TeleDongle, we recommend
3980 updating the altimeter first, before updating TeleDongle. However,
3981 note that TeleDongle rarely need to be updated. Any firmware version
3982 1.0.1 or later will work, version 1.2.1 may have improved receiver
3983 performance slightly.
3986 Self-programmable devices (TeleMega, TeleMetrum v2 and EasyMini)
3987 are reprogrammed by connecting them to your computer over USB
3991 Updating TeleMega, TeleMetrum v2 or EasyMini Firmware
3993 <orderedlist inheritnum='inherit' numeration='arabic'>
3996 Attach a battery and power switch to the target
3997 device. Power up the device.
4002 Using a Micro USB cable, connect the target device to your
4003 computer's USB socket.
4008 Run AltosUI, and select 'Flash Image' from the File menu.
4013 Select the target device in the Device Selection dialog.
4018 Select the image you want to flash to the device, which
4019 should have a name in the form
4020 <product>-v<product-version>-<software-version>.ihx, such
4021 as TeleMega-v1.0-1.3.0.ihx.
4026 Make sure the configuration parameters are reasonable
4027 looking. If the serial number and/or RF configuration
4028 values aren't right, you'll need to change them.
4033 Hit the 'OK' button and the software should proceed to flash
4034 the device with new firmware, showing a progress bar.
4039 Verify that the device is working by using the 'Configure
4040 Altimeter' item to check over the configuration.
4045 <title>Recovering From Self-Flashing Failure</title>
4047 If the firmware loading fails, it can leave the device
4048 unable to boot. Not to worry, you can force the device to
4049 start the boot loader instead, which will let you try to
4050 flash the device again.
4053 On each device, connecting two pins from one of the exposed
4054 connectors will force the boot loader to start, even if the
4055 regular operating system has been corrupted in some way.
4059 <term>TeleMega</term>
4062 Connect pin 6 and pin 1 of the companion connector. Pin 1
4063 can be identified by the square pad around it, and then
4064 the pins could sequentially across the board. Be very
4065 careful to <emphasis>not</emphasis> short pin 8 to
4066 anything as that is connected directly to the battery. Pin
4067 7 carries 3.3V and the board will crash if that is
4068 connected to pin 1, but shouldn't damage the board.
4073 <term>TeleMetrum v2</term>
4076 Connect pin 6 and pin 1 of the companion connector. Pin 1
4077 can be identified by the square pad around it, and then
4078 the pins could sequentially across the board. Be very
4079 careful to <emphasis>not</emphasis> short pin 8 to
4080 anything as that is connected directly to the battery. Pin
4081 7 carries 3.3V and the board will crash if that is
4082 connected to pin 1, but shouldn't damage the board.
4087 <term>EasyMini</term>
4090 Connect pin 6 and pin 1 of the debug connector, which is
4091 the six holes next to the beeper. Pin 1 can be identified
4092 by the square pad around it, and then the pins could
4093 sequentially across the board, making Pin 6 the one on the
4094 other end of the row.
4102 <title>Pair Programming</title>
4104 The big concept to understand is that you have to use a
4105 TeleMega, TeleMetrum or TeleDongle as a programmer to update a
4106 pair programmed device. Due to limited memory resources in the
4107 cc1111, we don't support programming directly over USB for these
4112 <title>Updating TeleMetrum v1.x Firmware</title>
4113 <orderedlist inheritnum='inherit' numeration='arabic'>
4116 Find the 'programming cable' that you got as part of the starter
4117 kit, that has a red 8-pin MicroMaTch connector on one end and a
4118 red 4-pin MicroMaTch connector on the other end.
4123 Take the 2 screws out of the TeleDongle case to get access
4124 to the circuit board.
4129 Plug the 8-pin end of the programming cable to the
4130 matching connector on the TeleDongle, and the 4-pin end to the
4131 matching connector on the TeleMetrum.
4132 Note that each MicroMaTch connector has an alignment pin that
4133 goes through a hole in the PC board when you have the cable
4139 Attach a battery to the TeleMetrum board.
4144 Plug the TeleDongle into your computer's USB port, and power
4150 Run AltosUI, and select 'Flash Image' from the File menu.
4155 Pick the TeleDongle device from the list, identifying it as the
4161 Select the image you want put on the TeleMetrum, which should have a
4162 name in the form telemetrum-v1.2-1.0.0.ihx. It should be visible
4163 in the default directory, if not you may have to poke around
4164 your system to find it.
4169 Make sure the configuration parameters are reasonable
4170 looking. If the serial number and/or RF configuration
4171 values aren't right, you'll need to change them.
4176 Hit the 'OK' button and the software should proceed to flash
4177 the TeleMetrum with new firmware, showing a progress bar.
4182 Confirm that the TeleMetrum board seems to have updated OK, which you
4183 can do by plugging in to it over USB and using a terminal program
4184 to connect to the board and issue the 'v' command to check
4190 If something goes wrong, give it another try.
4196 <title>Updating TeleMini Firmware</title>
4197 <orderedlist inheritnum='inherit' numeration='arabic'>
4200 You'll need a special 'programming cable' to reprogram the
4201 TeleMini. You can make your own using an 8-pin MicroMaTch
4202 connector on one end and a set of four pins on the other.
4207 Take the 2 screws out of the TeleDongle case to get access
4208 to the circuit board.
4213 Plug the 8-pin end of the programming cable to the matching
4214 connector on the TeleDongle, and the 4-pins into the holes
4215 in the TeleMini circuit board. Note that the MicroMaTch
4216 connector has an alignment pin that goes through a hole in
4217 the PC board when you have the cable oriented correctly, and
4218 that pin 1 on the TeleMini board is marked with a square pad
4219 while the other pins have round pads.
4224 Attach a battery to the TeleMini board.
4229 Plug the TeleDongle into your computer's USB port, and power
4235 Run AltosUI, and select 'Flash Image' from the File menu.
4240 Pick the TeleDongle device from the list, identifying it as the
4246 Select the image you want put on the TeleMini, which should have a
4247 name in the form telemini-v1.0-1.0.0.ihx. It should be visible
4248 in the default directory, if not you may have to poke around
4249 your system to find it.
4254 Make sure the configuration parameters are reasonable
4255 looking. If the serial number and/or RF configuration
4256 values aren't right, you'll need to change them.
4261 Hit the 'OK' button and the software should proceed to flash
4262 the TeleMini with new firmware, showing a progress bar.
4267 Confirm that the TeleMini board seems to have updated OK, which you
4268 can do by configuring it over the radio link through the TeleDongle, or
4269 letting it come up in “flight” mode and listening for telemetry.
4274 If something goes wrong, give it another try.
4280 <title>Updating TeleDongle Firmware</title>
4282 Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
4283 firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
4285 <orderedlist inheritnum='inherit' numeration='arabic'>
4288 Find the 'programming cable' that you got as part of the starter
4289 kit, that has a red 8-pin MicroMaTch connector on one end and a
4290 red 4-pin MicroMaTch connector on the other end.
4295 Find the USB cable that you got as part of the starter kit, and
4296 plug the “mini” end in to the mating connector on TeleMetrum or TeleDongle.
4301 Take the 2 screws out of the TeleDongle case to get access
4302 to the circuit board.
4307 Plug the 8-pin end of the programming cable to the
4308 matching connector on the programmer, and the 4-pin end to the
4309 matching connector on the TeleDongle.
4310 Note that each MicroMaTch connector has an alignment pin that
4311 goes through a hole in the PC board when you have the cable
4317 Attach a battery to the TeleMetrum board if you're using one.
4322 Plug both the programmer and the TeleDongle into your computer's USB
4323 ports, and power up the programmer.
4328 Run AltosUI, and select 'Flash Image' from the File menu.
4333 Pick the programmer device from the list, identifying it as the
4339 Select the image you want put on the TeleDongle, which should have a
4340 name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
4341 in the default directory, if not you may have to poke around
4342 your system to find it.
4347 Make sure the configuration parameters are reasonable
4348 looking. If the serial number and/or RF configuration
4349 values aren't right, you'll need to change them. The TeleDongle
4350 serial number is on the “bottom” of the circuit board, and can
4351 usually be read through the translucent blue plastic case without
4352 needing to remove the board from the case.
4357 Hit the 'OK' button and the software should proceed to flash
4358 the TeleDongle with new firmware, showing a progress bar.
4363 Confirm that the TeleDongle board seems to have updated OK, which you
4364 can do by plugging in to it over USB and using a terminal program
4365 to connect to the board and issue the 'v' command to check
4366 the version, etc. Once you're happy, remove the programming cable
4367 and put the cover back on the TeleDongle.
4372 If something goes wrong, give it another try.
4377 Be careful removing the programming cable from the locking 8-pin
4378 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
4379 screwdriver or knife blade to gently pry the locking ears out
4380 slightly to extract the connector. We used a locking connector on
4381 TeleMetrum to help ensure that the cabling to companion boards
4382 used in a rocket don't ever come loose accidentally in flight.
4387 <title>Hardware Specifications</title>
4390 TeleMega Specifications
4395 Recording altimeter for model rocketry.
4400 Supports dual deployment and four auxiliary pyro channels
4401 (a total of 6 events).
4406 70cm 40mW ham-band transceiver for telemetry down-link.
4411 Barometric pressure sensor good to 100k feet MSL.
4416 1-axis high-g accelerometer for motor characterization, capable of
4422 9-axis IMU including integrated 3-axis accelerometer,
4423 3-axis gyroscope and 3-axis magnetometer.
4428 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
4433 On-board 8 Megabyte non-volatile memory for flight data storage.
4438 USB interface for battery charging, configuration, and data recovery.
4443 Fully integrated support for Li-Po rechargeable batteries.
4448 Can use either main system Li-Po or optional separate pyro battery
4454 3.25 x 1.25 inch board designed to fit inside 38mm air-frame coupler tube.
4461 TeleMetrum v2 Specifications
4466 Recording altimeter for model rocketry.
4471 Supports dual deployment (can fire 2 ejection charges).
4476 70cm, 40mW ham-band transceiver for telemetry down-link.
4481 Barometric pressure sensor good to 100k feet MSL.
4486 1-axis high-g accelerometer for motor characterization, capable of
4492 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
4497 On-board 8 Megabyte non-volatile memory for flight data storage.
4502 USB interface for battery charging, configuration, and data recovery.
4507 Fully integrated support for Li-Po rechargeable batteries.
4512 Uses Li-Po to fire e-matches, can be modified to support
4513 optional separate pyro battery if needed.
4518 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
4524 <title>TeleMetrum v1 Specifications</title>
4528 Recording altimeter for model rocketry.
4533 Supports dual deployment (can fire 2 ejection charges).
4538 70cm, 10mW ham-band transceiver for telemetry down-link.
4543 Barometric pressure sensor good to 45k feet MSL.
4548 1-axis high-g accelerometer for motor characterization, capable of
4549 +/- 50g using default part.
4554 On-board, integrated GPS receiver with 5Hz update rate capability.
4559 On-board 1 megabyte non-volatile memory for flight data storage.
4564 USB interface for battery charging, configuration, and data recovery.
4569 Fully integrated support for Li-Po rechargeable batteries.
4574 Uses Li-Po to fire e-matches, can be modified to support
4575 optional separate pyro battery if needed.
4580 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
4587 TeleMini v2.0 Specifications
4592 Recording altimeter for model rocketry.
4597 Supports dual deployment (can fire 2 ejection charges).
4602 70cm, 10mW ham-band transceiver for telemetry down-link.
4607 Barometric pressure sensor good to 100k feet MSL.
4612 On-board 1 megabyte non-volatile memory for flight data storage.
4617 USB interface for configuration, and data recovery.
4622 Support for Li-Po rechargeable batteries (using an
4623 external charger), or any 3.7-15V external battery.
4628 Uses Li-Po to fire e-matches, can be modified to support
4629 optional separate pyro battery if needed.
4634 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
4641 TeleMini v1.0 Specifications
4646 Recording altimeter for model rocketry.
4651 Supports dual deployment (can fire 2 ejection charges).
4656 70cm, 10mW ham-band transceiver for telemetry down-link.
4661 Barometric pressure sensor good to 45k feet MSL.
4666 On-board 5 kilobyte non-volatile memory for flight data storage.
4671 RF interface for configuration, and data recovery.
4676 Support for Li-Po rechargeable batteries, using an external charger.
4681 Uses Li-Po to fire e-matches, can be modified to support
4682 optional separate pyro battery if needed.
4687 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube.
4694 EasyMini Specifications
4699 Recording altimeter for model rocketry.
4704 Supports dual deployment (can fire 2 ejection charges).
4709 Barometric pressure sensor good to 100k feet MSL.
4714 On-board 1 megabyte non-volatile memory for flight data storage.
4719 USB interface for configuration, and data recovery.
4724 Support for Li-Po rechargeable batteries (using an
4725 external charger), or any 3.7-15V external battery.
4730 Uses Li-Po to fire e-matches, can be modified to support
4731 optional separate pyro battery if needed.
4736 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
4745 <emphasis>TeleMetrum seems to shut off when disconnected from the
4746 computer.</emphasis> <?linebreak?>
4747 Make sure the battery is adequately charged. Remember the
4748 unit will pull more power than the USB port can deliver before the
4749 GPS enters “locked” mode. The battery charges best when TeleMetrum
4753 <emphasis>It's impossible to stop the TeleDongle when it's in “p” mode, I have
4754 to unplug the USB cable? </emphasis><?linebreak?>
4755 Make sure you have tried to “escape out” of
4756 this mode. If this doesn't work the reboot procedure for the
4757 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
4758 outgoing buffer IF your “escape out” ('~~') does not work.
4759 At this point using either 'ao-view' (or possibly
4760 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
4764 <emphasis>The amber LED (on the TeleMetrum) lights up when both
4765 battery and USB are connected. Does this mean it's charging?
4766 </emphasis><?linebreak?>
4767 Yes, the yellow LED indicates the charging at the 'regular' rate.
4768 If the led is out but the unit is still plugged into a USB port,
4769 then the battery is being charged at a 'trickle' rate.
4772 <emphasis>There are no “dit-dah-dah-dit” sound or lights like the manual
4773 mentions?</emphasis><?linebreak?>
4774 That's the “pad” mode. Weak batteries might be the problem.
4775 It is also possible that the flight computer is horizontal and the
4777 is instead a “dit-dit” meaning 'idle'. For TeleMini, it's possible that
4778 it received a command packet which would have left it in “pad” mode.
4781 <emphasis>How do I save flight data?</emphasis><?linebreak?>
4782 Live telemetry is written to file(s) whenever AltosUI is connected
4783 to the TeleDongle. The file area defaults to ~/TeleMetrum
4784 but is easily changed using the menus in AltosUI. The files that
4785 are written end in '.telem'. The after-flight
4786 data-dumped files will end in .eeprom and represent continuous data
4787 unlike the .telem files that are subject to losses
4788 along the RF data path.
4789 See the above instructions on what and how to save the eeprom stored
4790 data after physically retrieving your altimeter. Make sure to save
4791 the on-board data after each flight; while the TeleMetrum can store
4792 multiple flights, you never know when you'll lose the altimeter...
4796 <title>Notes for Older Software</title>
4799 Before AltosUI was written, using Altus Metrum devices required
4800 some finesse with the Linux command line. There was a limited
4801 GUI tool, ao-view, which provided functionality similar to the
4802 Monitor Flight window in AltosUI, but everything else was a
4803 fairly 80's experience. This appendix includes documentation for
4804 using that software.
4808 Both TeleMetrum and TeleDongle can be directly communicated
4809 with using USB ports. The first thing you should try after getting
4810 both units plugged into to your computer's USB port(s) is to run
4811 'ao-list' from a terminal-window to see what port-device-name each
4812 device has been assigned by the operating system.
4813 You will need this information to access the devices via their
4814 respective on-board firmware and data using other command line
4815 programs in the AltOS software suite.
4818 TeleMini can be communicated with through a TeleDongle device
4819 over the radio link. When first booted, TeleMini listens for a
4820 TeleDongle device and if it receives a packet, it goes into
4821 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be
4822 launched. The easiest way to get it talking is to start the
4823 communication link on the TeleDongle and the power up the
4827 To access the device's firmware for configuration you need a terminal
4828 program such as you would use to talk to a modem. The software
4829 authors prefer using the program 'cu' which comes from the UUCP package
4830 on most Unix-like systems such as Linux. An example command line for
4831 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
4832 indicated from running the
4833 ao-list program. Another reasonable terminal program for Linux is
4834 'cutecom'. The default 'escape'
4835 character used by CU (i.e. the character you use to
4836 issue commands to cu itself instead of sending the command as input
4837 to the connected device) is a '~'. You will need this for use in
4838 only two different ways during normal operations. First is to exit
4839 the program by sending a '~.' which is called a 'escape-disconnect'
4840 and allows you to close-out from 'cu'. The
4841 second use will be outlined later.
4844 All of the Altus Metrum devices share the concept of a two level
4845 command set in their firmware.
4846 The first layer has several single letter commands. Once
4847 you are using 'cu' (or 'cutecom') sending (typing) a '?'
4848 returns a full list of these
4849 commands. The second level are configuration sub-commands accessed
4850 using the 'c' command, for
4851 instance typing 'c?' will give you this second level of commands
4852 (all of which require the
4853 letter 'c' to access). Please note that most configuration options
4854 are stored only in Flash memory; TeleDongle doesn't provide any storage
4855 for these options and so they'll all be lost when you unplug it.
4858 Try setting these configuration ('c' or second level menu) values. A good
4859 place to start is by setting your call sign. By default, the boards
4860 use 'N0CALL' which is cute, but not exactly legal!
4861 Spend a few minutes getting comfortable with the units, their
4862 firmware, and 'cu' (or possibly 'cutecom').
4863 For instance, try to send
4864 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
4865 Verify you can connect and disconnect from the units while in your
4866 terminal program by sending the escape-disconnect mentioned above.
4869 To set the radio frequency, use the 'c R' command to specify the
4870 radio transceiver configuration parameter. This parameter is computed
4871 using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
4872 the standard calibration reference frequency, 'S', (normally 434.550MHz):
4876 Round the result to the nearest integer value.
4877 As with all 'c' sub-commands, follow this with a 'c w' to write the
4878 change to the parameter block in the on-board flash on
4879 your altimeter board if you want the change to stay in place across reboots.
4882 To set the apogee delay, use the 'c d' command.
4883 As with all 'c' sub-commands, follow this with a 'c w' to write the
4884 change to the parameter block in the on-board DataFlash chip.
4887 To set the main deployment altitude, use the 'c m' command.
4888 As with all 'c' sub-commands, follow this with a 'c w' to write the
4889 change to the parameter block in the on-board DataFlash chip.
4892 To calibrate the radio frequency, connect the UHF antenna port to a
4893 frequency counter, set the board to 434.550MHz, and use the 'C'
4894 command to generate a CW carrier. Wait for the transmitter temperature
4895 to stabilize and the frequency to settle down.
4896 Then, divide 434.550 MHz by the
4897 measured frequency and multiply by the current radio cal value show
4898 in the 'c s' command. For an unprogrammed board, the default value
4899 is 1186611 for cc1111 based products and 7119667 for cc1120
4900 based products. Take the resulting integer and program it using the 'c f'
4901 command. Testing with the 'C' command again should show a carrier
4902 within a few tens of Hertz of the intended frequency.
4903 As with all 'c' sub-commands, follow this with a 'c w' to write the
4904 change to the configuration memory.
4907 Note that the 'reboot' command, which is very useful on the altimeters,
4908 will likely just cause problems with the dongle. The *correct* way
4909 to reset the dongle is just to unplug and re-plug it.
4912 A fun thing to do at the launch site and something you can do while
4913 learning how to use these units is to play with the radio link access
4914 between an altimeter and the TeleDongle. Be aware that you *must* create
4915 some physical separation between the devices, otherwise the link will
4916 not function due to signal overload in the receivers in each device.
4919 Now might be a good time to take a break and read the rest of this
4920 manual, particularly about the two “modes” that the altimeters
4921 can be placed in. TeleMetrum uses the position of the device when booting
4922 up will determine whether the unit is in “pad” or “idle” mode. TeleMini
4923 enters “idle” mode when it receives a command packet within the first 5 seconds
4924 of being powered up, otherwise it enters “pad” mode.
4927 You can access an altimeter in idle mode from the TeleDongle's USB
4928 connection using the radio link
4929 by issuing a 'p' command to the TeleDongle. Practice connecting and
4930 disconnecting ('~~' while using 'cu') from the altimeter. If
4931 you cannot escape out of the “p” command, (by using a '~~' when in
4932 CU) then it is likely that your kernel has issues. Try a newer version.
4935 Using this radio link allows you to configure the altimeter, test
4936 fire e-matches and igniters from the flight line, check pyro-match
4937 continuity and so forth. You can leave the unit turned on while it
4938 is in 'idle mode' and then place the
4939 rocket vertically on the launch pad, walk away and then issue a
4940 reboot command. The altimeter will reboot and start sending data
4941 having changed to the “pad” mode. If the TeleDongle is not receiving
4942 this data, you can disconnect 'cu' from the TeleDongle using the
4943 procedures mentioned above and THEN connect to the TeleDongle from
4944 inside 'ao-view'. If this doesn't work, disconnect from the
4945 TeleDongle, unplug it, and try again after plugging it back in.
4948 In order to reduce the chance of accidental firing of pyrotechnic
4949 charges, the command to fire a charge is intentionally somewhat
4950 difficult to type, and the built-in help is slightly cryptic to
4951 prevent accidental echoing of characters from the help text back at
4952 the board from firing a charge. The command to fire the apogee
4953 drogue charge is 'i DoIt drogue' and the command to fire the main
4954 charge is 'i DoIt main'.
4957 On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
4958 and 'ao-view' will both auditorily announce and visually indicate
4960 Now you can launch knowing that you have a good data path and
4961 good satellite lock for flight data and recovery. Remember
4962 you MUST tell ao-view to connect to the TeleDongle explicitly in
4963 order for ao-view to be able to receive data.
4966 The altimeters provide RDF (radio direction finding) tones on
4967 the pad, during descent and after landing. These can be used to
4968 locate the rocket using a directional antenna; the signal
4969 strength providing an indication of the direction from receiver to rocket.
4972 TeleMetrum also provides GPS tracking data, which can further simplify
4973 locating the rocket once it has landed. (The last good GPS data
4974 received before touch-down will be on the data screen of 'ao-view'.)
4977 Once you have recovered the rocket you can download the eeprom
4978 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
4979 either a USB cable or over the radio link using TeleDongle.
4980 And by following the man page for 'ao-postflight' you can create
4981 various data output reports, graphs, and even KML data to see the
4982 flight trajectory in Google-earth. (Moving the viewing angle making
4983 sure to connect the yellow lines while in Google-earth is the proper
4987 As for ao-view.... some things are in the menu but don't do anything
4988 very useful. The developers have stopped working on ao-view to focus
4989 on a new, cross-platform ground station program. So ao-view may or
4990 may not be updated in the future. Mostly you just use
4991 the Log and Device menus. It has a wonderful display of the incoming
4992 flight data and I am sure you will enjoy what it has to say to you
4993 once you enable the voice output!
4997 <title>Drill Templates</title>
4999 These images, when printed, provide precise templates for the
5000 mounting holes in Altus Metrum flight computers
5003 <title>TeleMega template</title>
5005 TeleMega has overall dimensions of 1.250 x 3.250 inches, and
5006 the mounting holes are sized for use with 4-40 or M3 screws.
5009 <mediaobject id="TeleMegaTemplate">
5011 <imagedata format="SVG" fileref="telemega-outline.svg"/>
5017 <title>TeleMetrum template</title>
5019 TeleMetrum has overall dimensions of 1.000 x 2.750 inches, and the
5020 mounting holes are sized for use with 4-40 or M3 screws.
5023 <mediaobject id="TeleMetrumTemplate">
5025 <imagedata format="SVG" fileref="telemetrum.svg"/>
5031 <title>TeleMini v2/EasyMini template</title>
5033 TeleMini v2 and EasyMini have overall dimensions of 0.800 x 1.500 inches, and the
5034 mounting holes are sized for use with 4-40 or M3 screws.
5037 <mediaobject id="MiniTemplate">
5039 <imagedata format="SVG" fileref="easymini-outline.svg"/>
5045 <title>TeleMini v1 template</title>
5047 TeleMini has overall dimensions of 0.500 x 1.500 inches, and the
5048 mounting holes are sized for use with 2-56 or M2 screws.
5051 <mediaobject id="TeleMiniTemplate">
5053 <imagedata format="SVG" fileref="telemini.svg"/>
5060 <title>Calibration</title>
5062 There are only two calibrations required for TeleMetrum and
5063 TeleMega, and only one for TeleDongle, TeleMini and EasyMini.
5064 All boards are shipped from the factory pre-calibrated, but
5065 the procedures are documented here in case they are ever
5066 needed. Re-calibration is not supported by AltosUI, you must
5067 connect to the board with a serial terminal program and
5068 interact directly with the on-board command interpreter to
5072 <title>Radio Frequency</title>
5074 The radio frequency is synthesized from a clock based on the
5075 crystal on the board. The actual frequency of this oscillator
5076 must be measured to generate a calibration constant. While our
5078 bandwidth is wide enough to allow boards to communicate even when
5079 their oscillators are not on exactly the same frequency, performance
5080 is best when they are closely matched.
5081 Radio frequency calibration requires a calibrated frequency counter.
5082 Fortunately, once set, the variation in frequency due to aging and
5083 temperature changes is small enough that re-calibration by customers
5084 should generally not be required.
5087 To calibrate the radio frequency, connect the UHF antenna
5088 port to a frequency counter, set the board to 434.550MHz,
5089 and use the 'C' command in the on-board command interpreter
5090 to generate a CW carrier. For USB-enabled boards, this is
5091 best done over USB. For TeleMini v1, note that the only way
5092 to escape the 'C' command is via power cycle since the board
5093 will no longer be listening for commands once it starts
5094 generating a CW carrier.
5097 Wait for the transmitter temperature to stabilize and the frequency
5098 to settle down. Then, divide 434.550 MHz by the
5099 measured frequency and multiply by the current radio cal value show
5100 in the 'c s' command. For an unprogrammed board, the default value
5101 is 1186611. Take the resulting integer and program it using the 'c f'
5102 command. Testing with the 'C' command again should show a carrier
5103 within a few tens of Hertz of the intended frequency.
5104 As with all 'c' sub-commands, follow this with a 'c w' to write the
5105 change to the parameter block in the on-board storage chip.
5108 Note that any time you re-do the radio frequency calibration, the
5109 radio frequency is reset to the default 434.550 Mhz. If you want
5110 to use another frequency, you will have to set that again after
5111 calibration is completed.
5115 <title>TeleMetrum and TeleMega Accelerometers</title>
5117 While barometric sensors are factory-calibrated,
5118 accelerometers are not, and so each must be calibrated once
5119 installed in a flight computer. Explicitly calibrating the
5120 accelerometers also allows us to load any compatible device.
5121 We perform a two-point calibration using gravity.
5124 To calibrate the acceleration sensor, use the 'c a 0' command. You
5125 will be prompted to orient the board vertically with the UHF antenna
5126 up and press a key, then to orient the board vertically with the
5127 UHF antenna down and press a key. Note that the accuracy of this
5128 calibration depends primarily on how perfectly vertical and still
5129 the board is held during the cal process. As with all 'c'
5130 sub-commands, follow this with a 'c w' to write the
5131 change to the parameter block in the on-board DataFlash chip.
5134 The +1g and -1g calibration points are included in each telemetry
5135 frame and are part of the header stored in onboard flash to be
5136 downloaded after flight. We always store and return raw ADC
5137 samples for each sensor... so nothing is permanently “lost” or
5138 “damaged” if the calibration is poor.
5141 In the unlikely event an accel cal goes badly, it is possible
5142 that TeleMetrum or TeleMega may always come up in 'pad mode'
5143 and as such not be listening to either the USB or radio link.
5144 If that happens, there is a special hook in the firmware to
5145 force the board back in to 'idle mode' so you can re-do the
5146 cal. To use this hook, you just need to ground the SPI clock
5147 pin at power-on. This pin is available as pin 2 on the 8-pin
5148 companion connector, and pin 1 is ground. So either
5149 carefully install a fine-gauge wire jumper between the two
5150 pins closest to the index hole end of the 8-pin connector, or
5151 plug in the programming cable to the 8-pin connector and use
5152 a small screwdriver or similar to short the two pins closest
5153 to the index post on the 4-pin end of the programming cable,
5154 and power up the board. It should come up in 'idle mode'
5155 (two beeps), allowing a re-cal.
5160 <title>Release Notes</title>
5162 <title>Version 1.3.2</title>
5164 xmlns:xi="http://www.w3.org/2001/XInclude"
5165 href="release-notes-1.3.2.xsl"
5166 xpointer="xpointer(/article/*)"/>
5169 <title>Version 1.3.1</title>
5171 xmlns:xi="http://www.w3.org/2001/XInclude"
5172 href="release-notes-1.3.1.xsl"
5173 xpointer="xpointer(/article/*)"/>
5176 <title>Version 1.3</title>
5178 xmlns:xi="http://www.w3.org/2001/XInclude"
5179 href="release-notes-1.3.xsl"
5180 xpointer="xpointer(/article/*)"/>
5183 <title>Version 1.2.1</title>
5185 xmlns:xi="http://www.w3.org/2001/XInclude"
5186 href="release-notes-1.2.1.xsl"
5187 xpointer="xpointer(/article/*)"/>
5190 <title>Version 1.2</title>
5192 xmlns:xi="http://www.w3.org/2001/XInclude"
5193 href="release-notes-1.2.xsl"
5194 xpointer="xpointer(/article/*)"/>
5197 <title>Version 1.1.1</title>
5199 xmlns:xi="http://www.w3.org/2001/XInclude"
5200 href="release-notes-1.1.1.xsl"
5201 xpointer="xpointer(/article/*)"/>
5204 <title>Version 1.1</title>
5206 xmlns:xi="http://www.w3.org/2001/XInclude"
5207 href="release-notes-1.1.xsl"
5208 xpointer="xpointer(/article/*)"/>
5211 <title>Version 1.0.1</title>
5213 xmlns:xi="http://www.w3.org/2001/XInclude"
5214 href="release-notes-1.0.1.xsl"
5215 xpointer="xpointer(/article/*)"/>
5218 <title>Version 0.9.2</title>
5220 xmlns:xi="http://www.w3.org/2001/XInclude"
5221 href="release-notes-0.9.2.xsl"
5222 xpointer="xpointer(/article/*)"/>
5225 <title>Version 0.9</title>
5227 xmlns:xi="http://www.w3.org/2001/XInclude"
5228 href="release-notes-0.9.xsl"
5229 xpointer="xpointer(/article/*)"/>
5232 <title>Version 0.8</title>
5234 xmlns:xi="http://www.w3.org/2001/XInclude"
5235 href="release-notes-0.8.xsl"
5236 xpointer="xpointer(/article/*)"/>
5239 <title>Version 0.7.1</title>
5241 xmlns:xi="http://www.w3.org/2001/XInclude"
5242 href="release-notes-0.7.1.xsl"
5243 xpointer="xpointer(/article/*)"/>
5248 <!-- LocalWords: Altusmetrum
projects / fw / altos / blob