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 This document is released under the terms of the
31 <ulink url="http://creativecommons.org/licenses/by-sa/3.0/">
32 Creative Commons ShareAlike 3.0
39 <revnumber>1.3.2</revnumber>
40 <date>24 January 2014</date>
42 Bug fixes for TeleMega and AltosUI.
46 <revnumber>1.3.1</revnumber>
47 <date>21 January 2014</date>
49 Bug fixes for TeleMega and TeleMetrum v2.0 along with a few
50 small UI improvements.
54 <revnumber>1.3</revnumber>
55 <date>12 November 2013</date>
57 Updated for software version 1.3. Version 1.3 adds support
58 for TeleMega, TeleMetrum v2.0, TeleMini v2.0 and EasyMini
59 and fixes bugs in AltosUI and the AltOS firmware.
63 <revnumber>1.2.1</revnumber>
64 <date>21 May 2013</date>
66 Updated for software version 1.2. Version 1.2 adds support
67 for TeleBT and AltosDroid. It also adds a few minor features
68 and fixes bugs in AltosUI and the AltOS firmware.
72 <revnumber>1.2</revnumber>
73 <date>18 April 2013</date>
75 Updated for software version 1.2. Version 1.2 adds support
76 for MicroPeak and the MicroPeak USB interface.
80 <revnumber>1.1.1</revnumber>
81 <date>16 September 2012</date>
83 Updated for software version 1.1.1 Version 1.1.1 fixes a few
84 bugs found in version 1.1.
88 <revnumber>1.1</revnumber>
89 <date>13 September 2012</date>
91 Updated for software version 1.1. Version 1.1 has new
92 features but is otherwise compatible with version 1.0.
96 <revnumber>1.0</revnumber>
97 <date>24 August 2011</date>
99 Updated for software version 1.0. Note that 1.0 represents a
100 telemetry format change, meaning both ends of a link
101 (TeleMetrum/TeleMini and TeleDongle) must be updated or
102 communications will fail.
106 <revnumber>0.9</revnumber>
107 <date>18 January 2011</date>
109 Updated for software version 0.9. Note that 0.9 represents a
110 telemetry format change, meaning both ends of a link (TeleMetrum and
111 TeleDongle) must be updated or communications will fail.
115 <revnumber>0.8</revnumber>
116 <date>24 November 2010</date>
117 <revremark>Updated for software version 0.8 </revremark>
122 <title>Acknowledgments</title>
124 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing “The
125 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
126 Kit” which formed the basis of the original Getting Started chapter
127 in this manual. Bob was one of our first customers for a production
128 TeleMetrum, and his continued enthusiasm and contributions
129 are immensely gratifying and highly appreciated!
132 And thanks to Anthony (AJ) Towns for major contributions including
133 the AltosUI graphing and site map code and associated documentation.
134 Free software means that our customers and friends can become our
135 collaborators, and we certainly appreciate this level of
139 Have fun using these products, and we hope to meet all of you
140 out on the rocket flight line somewhere.
143 NAR #87103, TRA #12201
145 Keith Packard, KD7SQG
146 NAR #88757, TRA #12200
151 <title>Introduction and Overview</title>
153 Welcome to the Altus Metrum community! Our circuits and software reflect
154 our passion for both hobby rocketry and Free Software. We hope their
155 capabilities and performance will delight you in every way, but by
156 releasing all of our hardware and software designs under open licenses,
157 we also hope to empower you to take as active a role in our collective
161 The first device created for our community was TeleMetrum, a dual
162 deploy altimeter with fully integrated GPS and radio telemetry
163 as standard features, and a “companion interface” that will
164 support optional capabilities in the future. The latest version
165 of TeleMetrum, v2.0, has all of the same features but with
166 improved sensors and radio to offer increased performance.
169 Our second device was TeleMini, a dual deploy altimeter with
170 radio telemetry and radio direction finding. The first version
171 of this device was only 13mm by 38mm (½ inch by 1½ inches) and
172 could fit easily in an 18mm air-frame. The latest version, v2.0,
173 includes a beeper, USB data download and extended on-board
174 flight logging, along with an improved barometric sensor.
177 TeleMega is our most sophisticated device, including six pyro
178 channels (four of which are fully programmable), integrated GPS,
179 integrated gyroscopes for staging/air-start inhibit and high
180 performance telemetry.
183 EasyMini is a dual-deploy altimeter with logging and built-in
187 TeleDongle was our first ground station, providing a USB to RF
188 interfaces for communicating with the altimeters. Combined with
189 your choice of antenna and notebook computer, TeleDongle and our
190 associated user interface software form a complete ground
191 station capable of logging and displaying in-flight telemetry,
192 aiding rocket recovery, then processing and archiving flight
193 data for analysis and review.
196 For a slightly more portable ground station experience that also
197 provides direct rocket recovery support, TeleBT offers flight
198 monitoring and data logging using a Bluetooth™ connection between
199 the receiver and an Android device that has the AltosDroid
200 application installed from the Google Play store.
203 More products will be added to the Altus Metrum family over time, and
204 we currently envision that this will be a single, comprehensive manual
205 for the entire product family.
209 <title>Getting Started</title>
211 The first thing to do after you check the inventory of parts in your
212 “starter kit” is to charge the battery.
215 For TeleMetrum and TeleMega, the battery can be charged by plugging it into the
216 corresponding socket of the device and then using the USB
217 cable to plug the flight computer into your computer's USB socket. The
218 on-board circuitry will charge the battery whenever it is plugged
219 in, because the on-off switch does NOT control the
223 On TeleMetrum v1 boards, when the GPS chip is initially
224 searching for satellites, TeleMetrum will consume more current
225 than it pulls from the USB port, so the battery must be
226 attached in order to get satellite lock. Once GPS is locked,
227 the current consumption goes back down enough to enable charging
228 while running. So it's a good idea to fully charge the battery
229 as your first item of business so there is no issue getting and
230 maintaining satellite lock. The yellow charge indicator led
231 will go out when the battery is nearly full and the charger goes
232 to trickle charge. It can take several hours to fully recharge a
233 deeply discharged battery.
236 TeleMetrum v2.0 and TeleMega use a higher power battery charger,
237 allowing them to charge the battery while running the board at
238 maximum power. When the battery is charging, or when the board
239 is consuming a lot of power, the red LED will be lit. When the
240 battery is fully charged, the green LED will be lit. When the
241 battery is damaged or missing, both LEDs will be lit, which
245 The Lithium Polymer TeleMini and EasyMini battery can be charged by
246 disconnecting it from the board and plugging it into a
247 standalone battery charger such as the LipoCharger product
248 included in TeleMini Starter Kits, and connecting that via a USB
249 cable to a laptop or other USB power source.
252 You can also choose to use another battery with TeleMini v2.0
253 and EasyMini, anything supplying between 4 and 12 volts should
254 work fine (like a standard 9V battery), but if you are planning
255 to fire pyro charges, ground testing is required to verify that
256 the battery supplies enough current to fire your chosen e-matches.
259 The other active device in the starter kit is the TeleDongle USB to
260 RF interface. If you plug it in to your Mac or Linux computer it should
261 “just work”, showing up as a serial port device. Windows systems need
262 driver information that is part of the AltOS download to know that the
263 existing USB modem driver will work. We therefore recommend installing
264 our software before plugging in TeleDongle if you are using a Windows
265 computer. If you are using an older version of Linux and are having
266 problems, try moving to a fresher kernel (2.6.33 or newer).
269 Next you should obtain and install the AltOS software. The AltOS
270 distribution includes the AltosUI ground station program, current
272 images for all of the hardware, and a number of standalone
273 utilities that are rarely needed. Pre-built binary packages are
274 available for Linux, Microsoft Windows, and recent MacOSX
275 versions. Full source code and build instructions are also
276 available. The latest version may always be downloaded from
277 <ulink url="http://altusmetrum.org/AltOS"/>.
280 If you're using a TeleBT instead of the TeleDongle, you'll want to
281 install the AltosDroid application from the Google Play store on an
282 Android device. You don't need a data plan to use AltosDroid, but
283 without network access, the Map view will be less useful as it
284 won't contain any map data. You can also use TeleBT connected
285 over USB with your laptop computer; it acts exactly like a
286 TeleDongle. Anywhere this manual talks about TeleDongle, you can
287 also read that as 'and TeleBT when connected via USB'.
291 <title>Handling Precautions</title>
293 All Altus Metrum products are sophisticated electronic devices.
294 When handled gently and properly installed in an air-frame, they
295 will deliver impressive results. However, as with all electronic
296 devices, there are some precautions you must take.
299 The Lithium Polymer rechargeable batteries have an
300 extraordinary power density. This is great because we can fly with
301 much less battery mass than if we used alkaline batteries or previous
302 generation rechargeable batteries... but if they are punctured
303 or their leads are allowed to short, they can and will release their
305 Thus we recommend that you take some care when handling our batteries
306 and consider giving them some extra protection in your air-frame. We
307 often wrap them in suitable scraps of closed-cell packing foam before
308 strapping them down, for example.
311 The barometric sensors used on all of our flight computers are
312 sensitive to sunlight. In normal mounting situations, the baro sensor
313 and all of the other surface mount components
314 are “down” towards whatever the underlying mounting surface is, so
315 this is not normally a problem. Please consider this when designing an
316 installation in an air-frame with a see-through plastic payload bay. It
317 is particularly important to
318 consider this with TeleMini v1.0, both because the baro sensor is on the
319 “top” of the board, and because many model rockets with payload bays
320 use clear plastic for the payload bay! Replacing these with an opaque
321 cardboard tube, painting them, or wrapping them with a layer of masking
322 tape are all reasonable approaches to keep the sensor out of direct
326 The barometric sensor sampling port must be able to “breathe”,
327 both by not being covered by foam or tape or other materials that might
328 directly block the hole on the top of the sensor, and also by having a
329 suitable static vent to outside air.
332 As with all other rocketry electronics, Altus Metrum altimeters must
333 be protected from exposure to corrosive motor exhaust and ejection
338 <title>Altus Metrum Hardware</title>
340 <title>General Usage Instructions</title>
342 Here are general instructions for hooking up an Altus Metrum
343 flight computer. Instructions specific to each model will be
344 found in the section devoted to that model below.
347 To prevent electrical interference from affecting the
348 operation of the flight computer, it's important to always
349 twist pairs of wires connected to the board. Twist the switch
350 leads, the pyro leads and the battery leads. This reduces
351 interference through a mechanism called common mode rejection.
354 <title>Hooking Up Lithium Polymer Batteries</title>
356 All Altus Metrum flight computers have a two pin JST PH
357 series connector to connect up a single-cell Lithium Polymer
358 cell (3.7V nominal). You can purchase matching batteries
359 from the Altus Metrum store, or other vendors, or you can
360 make your own. Pin 1 of the connector is positive, pin 2 is
361 negative. Spark Fun sells a cable with the connector
362 attached, which they call a <ulink
363 url="https://www.sparkfun.com/products/9914">JST Jumper 2
364 Wire Assembly</ulink>.
367 Many RC vendors also sell lithium polymer batteries with
368 this same connector. All that we have found use the opposite
369 polarity, and if you use them that way, you will damage or
370 destroy the flight computer.
374 <title>Hooking Up Pyro Charges</title>
376 Altus Metrum flight computers always have two screws for
377 each pyro charge. This means you shouldn't need to put two
378 wires into a screw terminal or connect leads from pyro
379 charges together externally.
382 On the flight computer, one lead from each charge is hooked
383 to the positive battery terminal through the power switch.
384 The other lead is connected through the pyro circuit, which
385 is connected to the negative battery terminal when the pyro
390 <title>Hooking Up a Power Switch</title>
392 Altus Metrum flight computers need an external power switch
393 to turn them on. This disconnects both the computer and the
394 pyro charges from the battery, preventing the charges from
395 firing when in the Off position. The switch is in-line with
396 the positive battery terminal.
399 <title>Using an External Active Switch Circuit</title>
401 You can use an active switch circuit, such as the
402 Featherweight Magnetic Switch, with any Altus Metrum
403 flight computer. These require three connections, one to
404 the battery, one to the positive power input on the flight
405 computer and one to ground. Find instructions on how to
406 hook these up for each flight computer below. The follow
407 the instructions that come with your active switch to
413 <title>Using a Separate Pyro Battery</title>
415 As mentioned above in the section on hooking up pyro
416 charges, one lead for each of the pyro charges is connected
417 through the power switch directly to the positive battery
418 terminal. The other lead is connected to the pyro circuit,
419 which connects it to the negative battery terminal when the
420 pyro circuit is fired. The pyro circuit on all of the flight
421 computers is designed to handle up to 16V.
424 To use a separate pyro battery, connect the negative pyro
425 battery terminal to the flight computer ground terminal,
426 the positive battery terminal to the igniter and the other
427 igniter lead to the negative pyro terminal on the flight
428 computer. When the pyro channel fires, it will complete the
429 circuit between the negative pyro terminal and the ground
430 terminal, firing the igniter. Specific instructions on how
431 to hook this up will be found in each section below.
435 <title>Using a Different Kind of Battery</title>
437 EasyMini and TeleMini v2 are designed to use either a
438 lithium polymer battery or any other battery producing
439 between 4 and 12 volts, such as a rectangular 9V
440 battery. TeleMega and TeleMetrum are not designed for this,
441 and must only be powered by a lithium polymer battery. Find
442 instructions on how to use other batteries in the EasyMini
443 and TeleMini sections below.
448 <title>Specifications</title>
450 Here's the full set of Altus Metrum products, both in
451 production and retired.
454 <title>Altus Metrum Electronics</title>
455 <?dbfo keep-together="always"?>
456 <tgroup cols='8' align='center' colsep='1' rowsep='1'>
457 <colspec align='center' colwidth='*' colname='Device'/>
458 <colspec align='center' colwidth='*' colname='Barometer'/>
459 <colspec align='center' colwidth='*' colname='Z-axis accelerometer'/>
460 <colspec align='center' colwidth='*' colname='GPS'/>
461 <colspec align='center' colwidth='*' colname='3D sensors'/>
462 <colspec align='center' colwidth='*' colname='Storage'/>
463 <colspec align='center' colwidth='*' colname='RF'/>
464 <colspec align='center' colwidth='*' colname='Battery'/>
467 <entry align='center'>Device</entry>
468 <entry align='center'>Barometer</entry>
469 <entry align='center'>Z-axis accelerometer</entry>
470 <entry align='center'>GPS</entry>
471 <entry align='center'>3D sensors</entry>
472 <entry align='center'>Storage</entry>
473 <entry align='center'>RF Output</entry>
474 <entry align='center'>Battery</entry>
479 <entry>TeleMetrum v1.0</entry>
480 <entry><para>MP3H6115 10km (33k')</para></entry>
481 <entry><para>MMA2202 50g</para></entry>
482 <entry>SkyTraq</entry>
489 <entry>TeleMetrum v1.1</entry>
490 <entry><para>MP3H6115 10km (33k')</para></entry>
491 <entry><para>MMA2202 50g</para></entry>
492 <entry>SkyTraq</entry>
499 <entry>TeleMetrum v1.2</entry>
500 <entry><para>MP3H6115 10km (33k')</para></entry>
501 <entry><para>ADXL78 70g</para></entry>
502 <entry>SkyTraq</entry>
509 <entry>TeleMetrum v2.0</entry>
510 <entry><para>MS5607 30km (100k')</para></entry>
511 <entry><para>MMA6555 102g</para></entry>
512 <entry>uBlox Max-7Q</entry>
519 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
520 <entry><para>MP3H6115 10km (33k')</para></entry>
529 <entry>TeleMini <?linebreak?>v2.0</entry>
530 <entry><para>MS5607 30km (100k')</para></entry>
536 <entry>3.7-12V</entry>
539 <entry>EasyMini <?linebreak?>v1.0</entry>
540 <entry><para>MS5607 30km (100k')</para></entry>
546 <entry>3.7-12V</entry>
549 <entry>TeleMega <?linebreak?>v1.0</entry>
550 <entry><para>MS5607 30km (100k')</para></entry>
551 <entry><para>MMA6555 102g</para></entry>
552 <entry>uBlox Max-7Q</entry>
553 <entry><para>MPU6000 HMC5883</para></entry>
562 <title>Altus Metrum Boards</title>
563 <?dbfo keep-together="always"?>
564 <tgroup cols='6' align='center' colsep='1' rowsep='1'>
565 <colspec align='center' colwidth='*' colname='Device'/>
566 <colspec align='center' colwidth='*' colname='Connectors'/>
567 <colspec align='center' colwidth='*' colname='Screw Terminals'/>
568 <colspec align='center' colwidth='*' colname='Width'/>
569 <colspec align='center' colwidth='*' colname='Length'/>
570 <colspec align='center' colwidth='*' colname='Tube Size'/>
573 <entry align='center'>Device</entry>
574 <entry align='center'>Connectors</entry>
575 <entry align='center'>Screw Terminals</entry>
576 <entry align='center'>Width</entry>
577 <entry align='center'>Length</entry>
578 <entry align='center'>Tube Size</entry>
583 <entry>TeleMetrum</entry>
587 Companion<?linebreak?>
591 <entry><para>Apogee pyro <?linebreak?>Main pyro <?linebreak?>Switch</para></entry>
592 <entry>1 inch (2.54cm)</entry>
593 <entry>2 ¾ inch (6.99cm)</entry>
594 <entry>29mm coupler</entry>
597 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
604 Apogee pyro <?linebreak?>
607 <entry>½ inch (1.27cm)</entry>
608 <entry>1½ inch (3.81cm)</entry>
609 <entry>18mm coupler</entry>
612 <entry>TeleMini <?linebreak?>v2.0</entry>
620 Apogee pyro <?linebreak?>
621 Main pyro <?linebreak?>
622 Battery <?linebreak?>
625 <entry>0.8 inch (2.03cm)</entry>
626 <entry>1½ inch (3.81cm)</entry>
627 <entry>24mm coupler</entry>
630 <entry>EasyMini</entry>
637 Apogee pyro <?linebreak?>
638 Main pyro <?linebreak?>
639 Battery <?linebreak?>
642 <entry>0.8 inch (2.03cm)</entry>
643 <entry>1½ inch (3.81cm)</entry>
644 <entry>24mm coupler</entry>
647 <entry>TeleMega</entry>
651 Companion<?linebreak?>
656 Apogee pyro <?linebreak?>
657 Main pyro<?linebreak?>
658 Pyro A-D<?linebreak?>
662 <entry>1¼ inch (3.18cm)</entry>
663 <entry>3¼ inch (8.26cm)</entry>
664 <entry>38mm coupler</entry>
671 <title>TeleMetrum</title>
675 <imagedata fileref="telemetrum-v1.1-thside.jpg" width="5.5in" scalefit="1"/>
680 TeleMetrum is a 1 inch by 2¾ inch circuit board. It was designed to
681 fit inside coupler for 29mm air-frame tubing, but using it in a tube that
682 small in diameter may require some creativity in mounting and wiring
683 to succeed! The presence of an accelerometer means TeleMetrum should
684 be aligned along the flight axis of the airframe, and by default the ¼
685 wave UHF wire antenna should be on the nose-cone end of the board. The
686 antenna wire is about 7 inches long, and wiring for a power switch and
687 the e-matches for apogee and main ejection charges depart from the
688 fin can end of the board, meaning an ideal “simple” avionics
689 bay for TeleMetrum should have at least 10 inches of interior length.
692 <title>TeleMetrum Screw Terminals</title>
694 TeleMetrum has six screw terminals on the end of the board
695 opposite the telemetry antenna. Two are for the power
696 switch, and two each for the apogee and main igniter
697 circuits. Using the picture above and starting from the top,
698 the terminals are as follows:
701 <title>TeleMetrum Screw Terminals</title>
702 <?dbfo keep-together="always"?>
703 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
704 <colspec align='center' colwidth='*' colname='Pin #'/>
705 <colspec align='center' colwidth='2*' colname='Pin Name'/>
706 <colspec align='left' colwidth='5*' colname='Description'/>
709 <entry align='center'>Terminal #</entry>
710 <entry align='center'>Terminal Name</entry>
711 <entry align='center'>Description</entry>
717 <entry>Switch Output</entry>
718 <entry>Switch connection to flight computer</entry>
722 <entry>Switch Input</entry>
723 <entry>Switch connection to positive battery terminal</entry>
727 <entry>Main +</entry>
728 <entry>Main pyro channel common connection to battery +</entry>
732 <entry>Main -</entry>
733 <entry>Main pyro channel connection to pyro circuit</entry>
737 <entry>Apogee +</entry>
738 <entry>Apogee pyro channel common connection to battery +</entry>
742 <entry>Apogee -</entry>
743 <entry>Apogee pyro channel connection to pyro circuit</entry>
750 <title>Using a Separate Pyro Battery with TeleMetrum</title>
752 As described above, using an external pyro battery involves
753 connecting the negative battery terminal to the flight
754 computer ground, connecting the positive battery terminal to
755 one of the igniter leads and connecting the other igniter
756 lead to the per-channel pyro circuit connection.
759 To connect the negative battery terminal to the TeleMetrum
760 ground, insert a small piece of wire, 24 to 28 gauge
761 stranded, into the GND hole just above the screw terminal
762 strip and solder it in place.
765 Connecting the positive battery terminal to the pyro
766 charges must be done separate from TeleMetrum, by soldering
767 them together or using some other connector.
770 The other lead from each pyro charge is then inserted into
771 the appropriate per-pyro channel screw terminal (terminal 4 for the
772 Main charge, terminal 6 for the Apogee charge).
776 <title>Using an Active Switch with TeleMetrum</title>
778 As explained above, an external active switch requires three
779 connections, one to the positive battery terminal, one to
780 the flight computer positive input and one to ground.
783 The positive battery terminal is available on screw terminal
784 2, the positive flight computer input is on terminal 1. To
785 hook a lead to ground, solder a piece of wire, 24 to 28
786 gauge stranded, to the GND hole just above terminal 1.
791 <title>TeleMini v1.0</title>
795 <imagedata fileref="telemini-v1-top.jpg" width="5.5in" scalefit="1"/>
800 TeleMini v1.0 is ½ inches by 1½ inches. It was
801 designed to fit inside an 18mm air-frame tube, but using it in
802 a tube that small in diameter may require some creativity in
803 mounting and wiring to succeed! Since there is no
804 accelerometer, TeleMini can be mounted in any convenient
805 orientation. The default ¼ wave UHF wire antenna attached to
806 the center of one end of the board is about 7 inches long. Two
807 wires for the power switch are connected to holes in the
808 middle of the board. Screw terminals for the e-matches for
809 apogee and main ejection charges depart from the other end of
810 the board, meaning an ideal “simple” avionics bay for TeleMini
811 should have at least 9 inches of interior length.
814 <title>TeleMini v1.0 Screw Terminals</title>
816 TeleMini v1.0 has four screw terminals on the end of the
817 board opposite the telemetry antenna. Two are for the apogee
818 and two are for main igniter circuits. There are also wires
819 soldered to the board for the power switch. Using the
820 picture above and starting from the top for the terminals
821 and from the left for the power switch wires, the
822 connections are as follows:
825 <title>TeleMini v1.0 Connections</title>
826 <?dbfo keep-together="always"?>
827 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
828 <colspec align='center' colwidth='*' colname='Pin #'/>
829 <colspec align='center' colwidth='2*' colname='Pin Name'/>
830 <colspec align='left' colwidth='5*' colname='Description'/>
833 <entry align='center'>Terminal #</entry>
834 <entry align='center'>Terminal Name</entry>
835 <entry align='center'>Description</entry>
841 <entry>Apogee -</entry>
842 <entry>Apogee pyro channel connection to pyro circuit</entry>
846 <entry>Apogee +</entry>
847 <entry>Apogee pyro channel common connection to battery +</entry>
851 <entry>Main -</entry>
852 <entry>Main pyro channel connection to pyro circuit</entry>
856 <entry>Main +</entry>
857 <entry>Main pyro channel common connection to battery +</entry>
861 <entry>Switch Output</entry>
862 <entry>Switch connection to flight computer</entry>
866 <entry>Switch Input</entry>
867 <entry>Switch connection to positive battery terminal</entry>
874 <title>Using a Separate Pyro Battery with TeleMini v1.0</title>
876 As described above, using an external pyro battery involves
877 connecting the negative battery terminal to the flight
878 computer ground, connecting the positive battery terminal to
879 one of the igniter leads and connecting the other igniter
880 lead to the per-channel pyro circuit connection. Because
881 there is no solid ground connection to use on TeleMini, this
885 The only available ground connection on TeleMini v1.0 are
886 the two mounting holes next to the telemetry
887 antenna. Somehow connect a small piece of wire to one of
888 those holes and hook it to the negative pyro battery terminal.
891 Connecting the positive battery terminal to the pyro
892 charges must be done separate from TeleMini v1.0, by soldering
893 them together or using some other connector.
896 The other lead from each pyro charge is then inserted into
897 the appropriate per-pyro channel screw terminal (terminal 3 for the
898 Main charge, terminal 1 for the Apogee charge).
902 <title>Using an Active Switch with TeleMini v1.0</title>
904 As explained above, an external active switch requires three
905 connections, one to the positive battery terminal, one to
906 the flight computer positive input and one to ground. Again,
907 because TeleMini doesn't have any good ground connection,
908 this is not recommended.
911 The positive battery terminal is available on the Right
912 power switch wire, the positive flight computer input is on
913 the left power switch wire. Hook a lead to either of the
914 mounting holes for a ground connection.
919 <title>TeleMini v2.0</title>
923 <imagedata fileref="telemini-v2-top.jpg" width="5.5in" scalefit="1"/>
928 TeleMini v2.0 is 0.8 inches by 1½ inches. It adds more
929 on-board data logging memory, a built-in USB connector and
930 screw terminals for the battery and power switch. The larger
931 board fits in a 24mm coupler. There's also a battery connector
932 for a LiPo battery if you want to use one of those.
935 <title>TeleMini v2.0 Screw Terminals</title>
937 TeleMini v2.0 has two sets of four screw terminals on the end of the
938 board opposite the telemetry antenna. Using the picture
939 above, the top four have connections for the main pyro
940 circuit and an external battery and the bottom four have
941 connections for the apogee pyro circuit and the power
942 switch. Counting from the left, the connections are as follows:
945 <title>TeleMini v2.0 Connections</title>
946 <?dbfo keep-together="always"?>
947 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
948 <colspec align='center' colwidth='*' colname='Pin #'/>
949 <colspec align='center' colwidth='2*' colname='Pin Name'/>
950 <colspec align='left' colwidth='5*' colname='Description'/>
953 <entry align='center'>Terminal #</entry>
954 <entry align='center'>Terminal Name</entry>
955 <entry align='center'>Description</entry>
961 <entry>Main -</entry>
962 <entry>Main pyro channel connection to pyro circuit</entry>
966 <entry>Main +</entry>
967 <entry>Main pyro channel common connection to battery +</entry>
971 <entry>Battery +</entry>
972 <entry>Positive external battery terminal</entry>
976 <entry>Battery -</entry>
977 <entry>Negative external battery terminal</entry>
980 <entry>Bottom 1</entry>
981 <entry>Apogee -</entry>
982 <entry>Apogee pyro channel connection to pyro circuit</entry>
985 <entry>Bottom 2</entry>
986 <entry>Apogee +</entry>
987 <entry>Apogee pyro channel common connection to
991 <entry>Bottom 3</entry>
992 <entry>Switch Output</entry>
993 <entry>Switch connection to flight computer</entry>
996 <entry>Bottom 4</entry>
997 <entry>Switch Input</entry>
998 <entry>Switch connection to positive battery terminal</entry>
1005 <title>Using a Separate Pyro Battery with TeleMini v2.0</title>
1007 As described above, using an external pyro battery involves
1008 connecting the negative battery terminal to the flight
1009 computer ground, connecting the positive battery terminal to
1010 one of the igniter leads and connecting the other igniter
1011 lead to the per-channel pyro circuit connection.
1014 To connect the negative pyro battery terminal to TeleMini
1015 ground, connect it to the negative external battery
1016 connection, top terminal 4.
1019 Connecting the positive battery terminal to the pyro
1020 charges must be done separate from TeleMini v2.0, by soldering
1021 them together or using some other connector.
1024 The other lead from each pyro charge is then inserted into
1025 the appropriate per-pyro channel screw terminal (top
1026 terminal 1 for the Main charge, bottom terminal 1 for the
1031 <title>Using an Active Switch with TeleMini v2.0</title>
1033 As explained above, an external active switch requires three
1034 connections, one to the positive battery terminal, one to
1035 the flight computer positive input and one to ground. Use
1036 the negative external battery connection, top terminal 4 for
1040 The positive battery terminal is available on bottom
1041 terminal 4, the positive flight computer input is on the
1047 <title>EasyMini</title>
1051 <imagedata fileref="easymini-top.jpg" width="5.5in" scalefit="1"/>
1056 EasyMini is built on a 0.8 inch by 1½ inch circuit board. It's
1057 designed to fit in a 24mm coupler tube. The connectors and
1058 screw terminals match TeleMini v2.0, so you can easily swap between
1059 EasyMini and TeleMini.
1062 <title>EasyMini Screw Terminals</title>
1064 EasyMini has two sets of four screw terminals on the end of the
1065 board opposite the telemetry antenna. Using the picture
1066 above, the top four have connections for the main pyro
1067 circuit and an external battery and the bottom four have
1068 connections for the apogee pyro circuit and the power
1069 switch. Counting from the left, the connections are as follows:
1072 <title>EasyMini Connections</title>
1073 <?dbfo keep-together="always"?>
1074 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
1075 <colspec align='center' colwidth='*' colname='Pin #'/>
1076 <colspec align='center' colwidth='2*' colname='Pin Name'/>
1077 <colspec align='left' colwidth='5*' colname='Description'/>
1080 <entry align='center'>Terminal #</entry>
1081 <entry align='center'>Terminal Name</entry>
1082 <entry align='center'>Description</entry>
1087 <entry>Top 1</entry>
1088 <entry>Main -</entry>
1089 <entry>Main pyro channel connection to pyro circuit</entry>
1092 <entry>Top 2</entry>
1093 <entry>Main +</entry>
1094 <entry>Main pyro channel common connection to battery +</entry>
1097 <entry>Top 3</entry>
1098 <entry>Battery +</entry>
1099 <entry>Positive external battery terminal</entry>
1102 <entry>Top 4</entry>
1103 <entry>Battery -</entry>
1104 <entry>Negative external battery terminal</entry>
1107 <entry>Bottom 1</entry>
1108 <entry>Apogee -</entry>
1109 <entry>Apogee pyro channel connection to pyro circuit</entry>
1112 <entry>Bottom 2</entry>
1113 <entry>Apogee +</entry>
1114 <entry>Apogee pyro channel common connection to
1118 <entry>Bottom 3</entry>
1119 <entry>Switch Output</entry>
1120 <entry>Switch connection to flight computer</entry>
1123 <entry>Bottom 4</entry>
1124 <entry>Switch Input</entry>
1125 <entry>Switch connection to positive battery terminal</entry>
1132 <title>Using a Separate Pyro Battery with EasyMini</title>
1134 As described above, using an external pyro battery involves
1135 connecting the negative battery terminal to the flight
1136 computer ground, connecting the positive battery terminal to
1137 one of the igniter leads and connecting the other igniter
1138 lead to the per-channel pyro circuit connection.
1141 To connect the negative pyro battery terminal to TeleMini
1142 ground, connect it to the negative external battery
1143 connection, top terminal 4.
1146 Connecting the positive battery terminal to the pyro
1147 charges must be done separate from EasyMini, by soldering
1148 them together or using some other connector.
1151 The other lead from each pyro charge is then inserted into
1152 the appropriate per-pyro channel screw terminal (top
1153 terminal 1 for the Main charge, bottom terminal 1 for the
1158 <title>Using an Active Switch with EasyMini</title>
1160 As explained above, an external active switch requires three
1161 connections, one to the positive battery terminal, one to
1162 the flight computer positive input and one to ground. Use
1163 the negative external battery connection, top terminal 4 for
1167 The positive battery terminal is available on bottom
1168 terminal 4, the positive flight computer input is on the
1174 <title>TeleMega</title>
1178 <imagedata fileref="telemega-v1.0-top.jpg" width="5.5in" scalefit="1"/>
1183 TeleMega is a 1¼ inch by 3¼ inch circuit board. It was
1184 designed to easily fit in a 38mm coupler. Like TeleMetrum,
1185 TeleMega has an accelerometer and so it must be mounted so that
1186 the board is aligned with the flight axis. It can be mounted
1187 either antenna up or down.
1190 <title>TeleMega Screw Terminals</title>
1192 TeleMega has two sets of nine screw terminals on the end of
1193 the board opposite the telemetry antenna. They are as follows:
1196 <title>TeleMega Screw Terminals</title>
1197 <?dbfo keep-together="always"?>
1198 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
1199 <colspec align='center' colwidth='*' colname='Pin #'/>
1200 <colspec align='center' colwidth='2*' colname='Pin Name'/>
1201 <colspec align='left' colwidth='5*' colname='Description'/>
1204 <entry align='center'>Terminal #</entry>
1205 <entry align='center'>Terminal Name</entry>
1206 <entry align='center'>Description</entry>
1211 <entry>Top 1</entry>
1212 <entry>Switch Input</entry>
1213 <entry>Switch connection to positive battery terminal</entry>
1216 <entry>Top 2</entry>
1217 <entry>Switch Output</entry>
1218 <entry>Switch connection to flight computer</entry>
1221 <entry>Top 3</entry>
1223 <entry>Ground connection for use with external active switch</entry>
1226 <entry>Top 4</entry>
1227 <entry>Main -</entry>
1228 <entry>Main pyro channel connection to pyro circuit</entry>
1231 <entry>Top 5</entry>
1232 <entry>Main +</entry>
1233 <entry>Main pyro channel common connection to battery +</entry>
1236 <entry>Top 6</entry>
1237 <entry>Apogee -</entry>
1238 <entry>Apogee pyro channel connection to pyro circuit</entry>
1241 <entry>Top 7</entry>
1242 <entry>Apogee +</entry>
1243 <entry>Apogee pyro channel common connection to battery +</entry>
1246 <entry>Top 8</entry>
1248 <entry>D pyro channel connection to pyro circuit</entry>
1251 <entry>Top 9</entry>
1253 <entry>D pyro channel common connection to battery +</entry>
1256 <entry>Bottom 1</entry>
1258 <entry>Ground connection for negative pyro battery terminal</entry>
1261 <entry>Bottom 2</entry>
1263 <entry>Positive pyro battery terminal</entry>
1266 <entry>Bottom 3</entry>
1269 Power switch output. Use to connect main battery to
1274 <entry>Bottom 4</entry>
1276 <entry>A pyro channel connection to pyro circuit</entry>
1279 <entry>Bottom 5</entry>
1281 <entry>A pyro channel common connection to battery +</entry>
1284 <entry>Bottom 6</entry>
1286 <entry>B pyro channel connection to pyro circuit</entry>
1289 <entry>Bottom 7</entry>
1291 <entry>B pyro channel common connection to battery +</entry>
1294 <entry>Bottom 8</entry>
1296 <entry>C pyro channel connection to pyro circuit</entry>
1299 <entry>Bottom 9</entry>
1301 <entry>C pyro channel common connection to battery +</entry>
1308 <title>Using a Separate Pyro Battery with TeleMega</title>
1310 TeleMega provides explicit support for an external pyro
1311 battery. All that is required is to remove the jumper
1312 between the lipo terminal (Bottom 3) and the pyro terminal
1313 (Bottom 2). Then hook the negative pyro battery terminal to ground
1314 (Bottom 1) and the positive pyro battery to the pyro battery
1315 input (Bottom 2). You can then use the existing pyro screw
1316 terminals to hook up all of the pyro charges.
1320 <title>Using Only One Battery With TeleMega</title>
1322 Because TeleMega has built-in support for a separate pyro
1323 battery, if you want to fly with just one battery running
1324 both the computer and firing the charges, you need to
1325 connect the flight computer battery to the pyro
1326 circuit. TeleMega has two screw terminals for this—hook a
1327 wire from the Lipo terminal (Bottom 3) to the Pyro terminal
1332 <title>Using an Active Switch with TeleMega</title>
1334 As explained above, an external active switch requires three
1335 connections, one to the positive battery terminal, one to
1336 the flight computer positive input and one to ground.
1339 The positive battery terminal is available on Top terminal
1340 1, the positive flight computer input is on Top terminal
1341 2. Ground is on Top terminal 3.
1346 <title>Flight Data Recording</title>
1348 Each flight computer logs data at 100 samples per second
1349 during ascent and 10 samples per second during descent, except
1350 for TeleMini v1.0, which records ascent at 10 samples per
1351 second and descent at 1 sample per second. Data are logged to
1352 an on-board flash memory part, which can be partitioned into
1353 several equal-sized blocks, one for each flight.
1356 <title>Data Storage on Altus Metrum altimeters</title>
1357 <?dbfo keep-together="always"?>
1358 <tgroup cols='4' align='center' colsep='1' rowsep='1'>
1359 <colspec align='center' colwidth='*' colname='Device'/>
1360 <colspec align='center' colwidth='*' colname='Bytes per sample'/>
1361 <colspec align='center' colwidth='*' colname='Total storage'/>
1362 <colspec align='center' colwidth='*' colname='Minutes of
1366 <entry align='center'>Device</entry>
1367 <entry align='center'>Bytes per Sample</entry>
1368 <entry align='center'>Total Storage</entry>
1369 <entry align='center'>Minutes at Full Rate</entry>
1374 <entry>TeleMetrum v1.0</entry>
1380 <entry>TeleMetrum v1.1 v1.2</entry>
1386 <entry>TeleMetrum v2.0</entry>
1392 <entry>TeleMini v1.0</entry>
1398 <entry>TeleMini v2.0</entry>
1404 <entry>EasyMini</entry>
1410 <entry>TeleMega</entry>
1419 The on-board flash is partitioned into separate flight logs,
1420 each of a fixed maximum size. Increase the maximum size of
1421 each log and you reduce the number of flights that can be
1422 stored. Decrease the size and you can store more flights.
1425 Configuration data is also stored in the flash memory on
1426 TeleMetrum v1.x, TeleMini and EasyMini. This consumes 64kB
1427 of flash space. This configuration space is not available
1428 for storing flight log data. TeleMetrum v2.0 and TeleMega
1429 store configuration data in a bit of eeprom available within
1430 the processor chip, leaving that space available in flash for
1434 To compute the amount of space needed for a single flight, you
1435 can multiply the expected ascent time (in seconds) by 100
1436 times bytes-per-sample, multiply the expected descent time (in
1437 seconds) by 10 times the bytes per sample and add the two
1438 together. That will slightly under-estimate the storage (in
1439 bytes) needed for the flight. For instance, a TeleMetrum v2.0 flight spending
1440 20 seconds in ascent and 150 seconds in descent will take
1441 about (20 * 1600) + (150 * 160) = 56000 bytes of storage. You
1442 could store dozens of these flights in the on-board flash.
1445 The default size allows for several flights on each flight
1446 computer, except for TeleMini v1.0, which only holds data for a
1447 single flight. You can adjust the size.
1450 Altus Metrum flight computers will not overwrite existing
1451 flight data, so be sure to download flight data and erase it
1452 from the flight computer before it fills up. The flight
1453 computer will still successfully control the flight even if it
1454 cannot log data, so the only thing you will lose is the data.
1458 <title>Installation</title>
1460 A typical installation involves attaching
1461 only a suitable battery, a single pole switch for
1462 power on/off, and two pairs of wires connecting e-matches for the
1463 apogee and main ejection charges. All Altus Metrum products are
1464 designed for use with single-cell batteries with 3.7 volts
1465 nominal. TeleMini v2.0 and EasyMini may also be used with other
1466 batteries as long as they supply between 4 and 12 volts.
1469 The battery connectors are a standard 2-pin JST connector and
1470 match batteries sold by Spark Fun. These batteries are
1471 single-cell Lithium Polymer batteries that nominally provide 3.7
1472 volts. Other vendors sell similar batteries for RC aircraft
1473 using mating connectors, however the polarity for those is
1474 generally reversed from the batteries used by Altus Metrum
1475 products. In particular, the Tenergy batteries supplied for use
1476 in Featherweight flight computers are not compatible with Altus
1477 Metrum flight computers or battery chargers. <emphasis>Check
1478 polarity and voltage before connecting any battery not purchased
1479 from Altus Metrum or Spark Fun.</emphasis>
1482 By default, we use the unregulated output of the battery directly
1483 to fire ejection charges. This works marvelously with standard
1484 low-current e-matches like the J-Tek from MJG Technologies, and with
1485 Quest Q2G2 igniters. However, if you want or need to use a separate
1486 pyro battery, check out the “External Pyro Battery” section in this
1487 manual for instructions on how to wire that up. The altimeters are
1488 designed to work with an external pyro battery of no more than 15 volts.
1491 Ejection charges are wired directly to the screw terminal block
1492 at the aft end of the altimeter. You'll need a very small straight
1493 blade screwdriver for these screws, such as you might find in a
1494 jeweler's screwdriver set.
1497 Except for TeleMini v1.0, the flight computers also use the
1498 screw terminal block for the power switch leads. On TeleMini v1.0,
1499 the power switch leads are soldered directly to the board and
1500 can be connected directly to a switch.
1503 For most air-frames, the integrated antennas are more than
1504 adequate. However, if you are installing in a carbon-fiber or
1505 metal electronics bay which is opaque to RF signals, you may need to
1506 use off-board external antennas instead. In this case, you can
1507 replace the stock UHF antenna wire with an edge-launched SMA connector,
1508 and, on TeleMetrum v1, you can unplug the integrated GPS
1509 antenna and select an appropriate off-board GPS antenna with
1510 cable terminating in a U.FL connector.
1515 <title>System Operation</title>
1517 <title>Firmware Modes </title>
1519 The AltOS firmware build for the altimeters has two
1520 fundamental modes, “idle” and “flight”. Which of these modes
1521 the firmware operates in is determined at start up time. For
1522 TeleMetrum and TeleMega, which have accelerometers, the mode is
1523 controlled by the orientation of the
1524 rocket (well, actually the board, of course...) at the time
1525 power is switched on. If the rocket is “nose up”, then
1526 the flight computer assumes it's on a rail or rod being prepared for
1527 launch, so the firmware chooses flight mode. However, if the
1528 rocket is more or less horizontal, the firmware instead enters
1529 idle mode. Since TeleMini v2.0 and EasyMini don't have an
1530 accelerometer we can use to determine orientation, “idle” mode
1531 is selected if the board is connected via USB to a computer,
1532 otherwise the board enters “flight” mode. TeleMini v1.0
1533 selects “idle” mode if it receives a command packet within the
1534 first five seconds of operation.
1537 At power on, you will hear three beeps or see three flashes
1538 (“S” in Morse code for start up) and then a pause while
1539 the altimeter completes initialization and self test, and decides
1540 which mode to enter next.
1543 Here's a short summary of all of the modes and the beeping (or
1544 flashing, in the case of TeleMini v1) that accompanies each
1545 mode. In the description of the beeping pattern, “dit” means a
1546 short beep while "dah" means a long beep (three times as
1547 long). “Brap” means a long dissonant tone.
1549 <title>AltOS Modes</title>
1550 <?dbfo keep-together="always"?>
1551 <tgroup cols='4' align='center' colsep='1' rowsep='1'>
1552 <colspec align='center' colwidth='*' colname='Mode Name'/>
1553 <colspec align='center' colwidth='*' colname='Letter'/>
1554 <colspec align='center' colwidth='*' colname='Beeps'/>
1555 <colspec align='center' colwidth='*' colname='Description'/>
1558 <entry>Mode Name</entry>
1559 <entry>Abbreviation</entry>
1560 <entry>Beeps</entry>
1561 <entry>Description</entry>
1566 <entry>Startup</entry>
1568 <entry>dit dit dit</entry>
1571 Calibrating sensors, detecting orientation.
1578 <entry>dit dit</entry>
1581 Ready to accept commands over USB or radio link.
1588 <entry>dit dah dah dit</entry>
1591 Waiting for launch. Not listening for commands.
1596 <entry>Boost</entry>
1598 <entry>dah dit dit dit</entry>
1601 Accelerating upwards.
1608 <entry>dit dit dah dit</entry>
1611 Decelerating, but moving faster than 200m/s.
1616 <entry>Coast</entry>
1618 <entry>dah dit dah dit</entry>
1621 Decelerating, moving slower than 200m/s
1626 <entry>Drogue</entry>
1628 <entry>dah dit dit</entry>
1631 Descending after apogee. Above main height.
1638 <entry>dah dah</entry>
1641 Descending. Below main height.
1646 <entry>Landed</entry>
1648 <entry>dit dah dit dit</entry>
1651 Stable altitude for at least ten seconds.
1656 <entry>Sensor error</entry>
1658 <entry>dah dit dit dah</entry>
1661 Error detected during sensor calibration.
1670 In flight or “pad” mode, the altimeter engages the flight
1671 state machine, goes into transmit-only mode to send telemetry,
1672 and waits for launch to be detected. Flight mode is indicated
1673 by an “di-dah-dah-dit” (“P” for pad) on the beeper or lights,
1674 followed by beeps or flashes indicating the state of the
1675 pyrotechnic igniter continuity. One beep/flash indicates
1676 apogee continuity, two beeps/flashes indicate main continuity,
1677 three beeps/flashes indicate both apogee and main continuity,
1678 and one longer “brap” sound which is made by rapidly
1679 alternating between two tones indicates no continuity. For a
1680 dual deploy flight, make sure you're getting three beeps or
1681 flashes before launching! For apogee-only or motor eject
1682 flights, do what makes sense.
1685 If idle mode is entered, you will hear an audible “di-dit” or
1686 see two short flashes (“I” for idle), and the flight state
1687 machine is disengaged, thus no ejection charges will fire.
1688 The altimeters also listen for the radio link when in idle
1689 mode for requests sent via TeleDongle. Commands can be issued
1690 in idle mode over either USB or the radio link
1691 equivalently. TeleMini v1.0 only has the radio link. Idle
1692 mode is useful for configuring the altimeter, for extracting
1693 data from the on-board storage chip after flight, and for
1694 ground testing pyro charges.
1697 In “Idle” and “Pad” modes, once the mode indication
1698 beeps/flashes and continuity indication has been sent, if
1699 there is no space available to log the flight in on-board
1700 memory, the flight computer will emit a warbling tone (much
1701 slower than the “no continuity tone”)
1704 Here's a summary of all of the “pad” and “idle” mode indications.
1706 <title>Pad/Idle Indications</title>
1707 <?dbfo keep-together="always"?>
1708 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
1709 <colspec align='center' colwidth='*' colname='Name'/>
1710 <colspec align='center' colwidth='*' colname='Beeps'/>
1711 <colspec align='center' colwidth='*' colname='Description'/>
1715 <entry>Beeps</entry>
1716 <entry>Description</entry>
1721 <entry>Neither</entry>
1725 No continuity detected on either apogee or main
1731 <entry>Apogee</entry>
1735 Continuity detected only on apogee igniter.
1741 <entry>dit dit</entry>
1744 Continuity detected only on main igniter.
1750 <entry>dit dit dit</entry>
1753 Continuity detected on both igniters.
1758 <entry>Storage Full</entry>
1759 <entry>warble</entry>
1762 On-board data logging storage is full. This will
1763 not prevent the flight computer from safely
1764 controlling the flight or transmitting telemetry
1765 signals, but no record of the flight will be
1766 stored in on-board flash.
1775 Once landed, the flight computer will signal that by emitting
1776 the “Landed” sound described above, after which it will beep
1777 out the apogee height (in meters). Each digit is represented
1778 by a sequence of short “dit” beeps, with a pause between
1779 digits. A zero digit is represented with one long “dah”
1780 beep. The flight computer will continue to report landed mode
1781 and beep out the maximum height until turned off.
1784 One “neat trick” of particular value when TeleMetrum or TeleMega are used with
1785 very large air-frames, is that you can power the board up while the
1786 rocket is horizontal, such that it comes up in idle mode. Then you can
1787 raise the air-frame to launch position, and issue a 'reset' command
1788 via TeleDongle over the radio link to cause the altimeter to reboot and
1789 come up in flight mode. This is much safer than standing on the top
1790 step of a rickety step-ladder or hanging off the side of a launch
1791 tower with a screw-driver trying to turn on your avionics before
1792 installing igniters!
1795 TeleMini v1.0 is configured solely via the radio link. Of course, that
1796 means you need to know the TeleMini radio configuration values
1797 or you won't be able to communicate with it. For situations
1798 when you don't have the radio configuration values, TeleMini v1.0
1799 offers an 'emergency recovery' mode. In this mode, TeleMini is
1800 configured as follows:
1804 Sets the radio frequency to 434.550MHz
1809 Sets the radio calibration back to the factory value.
1814 Sets the callsign to N0CALL
1819 Does not go to 'pad' mode after five seconds.
1825 To get into 'emergency recovery' mode, first find the row of
1826 four small holes opposite the switch wiring. Using a short
1827 piece of small gauge wire, connect the outer two holes
1828 together, then power TeleMini up. Once the red LED is lit,
1829 disconnect the wire and the board should signal that it's in
1830 'idle' mode after the initial five second startup period.
1836 TeleMetrum and TeleMega include a complete GPS receiver. A
1837 complete explanation of how GPS works is beyond the scope of
1838 this manual, but the bottom line is that the GPS receiver
1839 needs to lock onto at least four satellites to obtain a solid
1840 3 dimensional position fix and know what time it is.
1843 The flight computers provide backup power to the GPS chip any time a
1844 battery is connected. This allows the receiver to “warm start” on
1845 the launch rail much faster than if every power-on were a GPS
1846 “cold start”. In typical operations, powering up
1847 on the flight line in idle mode while performing final air-frame
1848 preparation will be sufficient to allow the GPS receiver to cold
1849 start and acquire lock. Then the board can be powered down during
1850 RSO review and installation on a launch rod or rail. When the board
1851 is turned back on, the GPS system should lock very quickly, typically
1852 long before igniter installation and return to the flight line are
1857 <title>Controlling An Altimeter Over The Radio Link</title>
1859 One of the unique features of the Altus Metrum system is the
1860 ability to create a two way command link between TeleDongle
1861 and an altimeter using the digital radio transceivers
1862 built into each device. This allows you to interact with the
1863 altimeter from afar, as if it were directly connected to the
1867 Any operation which can be performed with a flight computer can
1868 either be done with the device directly connected to the
1869 computer via the USB cable, or through the radio
1870 link. TeleMini v1.0 doesn't provide a USB connector and so it is
1871 always communicated with over radio. Select the appropriate
1872 TeleDongle device when the list of devices is presented and
1873 AltosUI will interact with an altimeter over the radio link.
1876 One oddity in the current interface is how AltosUI selects the
1877 frequency for radio communications. Instead of providing
1878 an interface to specifically configure the frequency, it uses
1879 whatever frequency was most recently selected for the target
1880 TeleDongle device in Monitor Flight mode. If you haven't ever
1881 used that mode with the TeleDongle in question, select the
1882 Monitor Flight button from the top level UI, and pick the
1883 appropriate TeleDongle device. Once the flight monitoring
1884 window is open, select the desired frequency and then close it
1885 down again. All radio communications will now use that frequency.
1890 Save Flight Data—Recover flight data from the rocket without
1896 Configure altimeter apogee delays, main deploy heights
1897 and additional pyro event conditions
1898 to respond to changing launch conditions. You can also
1899 'reboot' the altimeter. Use this to remotely enable the
1900 flight computer by turning TeleMetrum or TeleMega on in “idle” mode,
1901 then once the air-frame is oriented for launch, you can
1902 reboot the altimeter and have it restart in pad mode
1903 without having to climb the scary ladder.
1908 Fire Igniters—Test your deployment charges without snaking
1909 wires out through holes in the air-frame. Simply assemble the
1910 rocket as if for flight with the apogee and main charges
1911 loaded, then remotely command the altimeter to fire the
1917 Operation over the radio link for configuring an altimeter, ground
1918 testing igniters, and so forth uses the same RF frequencies as flight
1919 telemetry. To configure the desired TeleDongle frequency, select
1920 the monitor flight tab, then use the frequency selector and
1921 close the window before performing other desired radio operations.
1924 The flight computers only enable radio commanding in 'idle' mode.
1925 TeleMetrum and TeleMega use the accelerometer to detect which orientation they
1926 start up in, so make sure you have the flight computer lying horizontally when you turn
1927 it on. Otherwise, it will start in 'pad' mode ready for
1928 flight, and will not be listening for command packets from TeleDongle.
1931 TeleMini listens for a command packet for five seconds after
1932 first being turned on, if it doesn't hear anything, it enters
1933 'pad' mode, ready for flight and will no longer listen for
1934 command packets. The easiest way to connect to TeleMini is to
1935 initiate the command and select the TeleDongle device. At this
1936 point, the TeleDongle will be attempting to communicate with
1937 the TeleMini. Now turn TeleMini on, and it should immediately
1938 start communicating with the TeleDongle and the desired
1939 operation can be performed.
1942 You can monitor the operation of the radio link by watching the
1943 lights on the devices. The red LED will flash each time a packet
1944 is transmitted, while the green LED will light up on TeleDongle when
1945 it is waiting to receive a packet from the altimeter.
1949 <title>Ground Testing </title>
1951 An important aspect of preparing a rocket using electronic deployment
1952 for flight is ground testing the recovery system. Thanks
1953 to the bi-directional radio link central to the Altus Metrum system,
1954 this can be accomplished in a TeleMega, TeleMetrum or TeleMini equipped rocket
1955 with less work than you may be accustomed to with other systems. It
1959 Just prep the rocket for flight, then power up the altimeter
1960 in “idle” mode (placing air-frame horizontal for TeleMetrum or TeleMega, or
1961 selecting the Configure Altimeter tab for TeleMini). This will cause
1962 the firmware to go into “idle” mode, in which the normal flight
1963 state machine is disabled and charges will not fire without
1964 manual command. You can now command the altimeter to fire the apogee
1965 or main charges from a safe distance using your computer and
1966 TeleDongle and the Fire Igniter tab to complete ejection testing.
1970 <title>Radio Link </title>
1972 Our flight computers all incorporate an RF transceiver, but
1973 it's not a full duplex system... each end can only be transmitting or
1974 receiving at any given moment. So we had to decide how to manage the
1978 By design, the altimeter firmware listens for the radio link when
1979 it's in “idle mode”, which
1980 allows us to use the radio link to configure the rocket, do things like
1981 ejection tests, and extract data after a flight without having to
1982 crack open the air-frame. However, when the board is in “flight
1983 mode”, the altimeter only
1984 transmits and doesn't listen at all. That's because we want to put
1985 ultimate priority on event detection and getting telemetry out of
1987 the radio in case the rocket crashes and we aren't able to extract
1991 We don't generally use a 'normal packet radio' mode like APRS
1992 because they're just too inefficient. The GFSK modulation we
1993 use is FSK with the base-band pulses passed through a Gaussian
1994 filter before they go into the modulator to limit the
1995 transmitted bandwidth. When combined with forward error
1996 correction and interleaving, this allows us to have a very
1997 robust 19.2 kilobit data link with only 10-40 milliwatts of
1998 transmit power, a whip antenna in the rocket, and a hand-held
1999 Yagi on the ground. We've had flights to above 21k feet AGL
2000 with great reception, and calculations suggest we should be
2001 good to well over 40k feet AGL with a 5-element yagi on the
2002 ground with our 10mW units and over 100k feet AGL with the
2003 40mW devices. We hope to fly boards to higher altitudes over
2004 time, and would of course appreciate customer feedback on
2005 performance in higher altitude flights!
2008 TeleMetrum v2.0 and TeleMega can send APRS if desired, and the
2009 interval between APRS packets can be configured. As each APRS
2010 packet takes a full second to transmit, we recommend an
2011 interval of at least 5 seconds to avoid consuming too much
2012 battery power or radio channel bandwidth.
2016 <title>Configurable Parameters</title>
2018 Configuring an Altus Metrum altimeter for flight is very
2019 simple. Even on our baro-only TeleMini and EasyMini boards, the use of a Kalman
2020 filter means there is no need to set a “mach delay”. The few
2021 configurable parameters can all be set using AltosUI over USB or
2022 or radio link via TeleDongle.
2025 <title>Radio Frequency</title>
2027 Altus Metrum boards support radio frequencies in the 70cm
2028 band. By default, the configuration interface provides a
2029 list of 10 “standard” frequencies in 100kHz channels starting at
2030 434.550MHz. However, the firmware supports use of
2031 any 50kHz multiple within the 70cm band. At any given
2032 launch, we highly recommend coordinating when and by whom each
2033 frequency will be used to avoid interference. And of course, both
2034 altimeter and TeleDongle must be configured to the same
2035 frequency to successfully communicate with each other.
2039 <title>Apogee Delay</title>
2041 Apogee delay is the number of seconds after the altimeter detects flight
2042 apogee that the drogue charge should be fired. In most cases, this
2043 should be left at the default of 0. However, if you are flying
2044 redundant electronics such as for an L3 certification, you may wish
2045 to set one of your altimeters to a positive delay so that both
2046 primary and backup pyrotechnic charges do not fire simultaneously.
2049 The Altus Metrum apogee detection algorithm fires exactly at
2050 apogee. If you are also flying an altimeter like the
2051 PerfectFlite MAWD, which only supports selecting 0 or 1
2052 seconds of apogee delay, you may wish to set the MAWD to 0
2053 seconds delay and set the TeleMetrum to fire your backup 2
2054 or 3 seconds later to avoid any chance of both charges
2055 firing simultaneously. We've flown several air-frames this
2056 way quite happily, including Keith's successful L3 cert.
2060 <title>Main Deployment Altitude</title>
2062 By default, the altimeter will fire the main deployment charge at an
2063 elevation of 250 meters (about 820 feet) above ground. We think this
2064 is a good elevation for most air-frames, but feel free to change this
2065 to suit. In particular, if you are flying two altimeters, you may
2067 deployment elevation for the backup altimeter to be something lower
2068 than the primary so that both pyrotechnic charges don't fire
2073 <title>Maximum Flight Log</title>
2075 Changing this value will set the maximum amount of flight
2076 log storage that an individual flight will use. The
2077 available storage is divided into as many flights of the
2078 specified size as can fit in the available space. You can
2079 download and erase individual flight logs. If you fill up
2080 the available storage, future flights will not get logged
2081 until you erase some of the stored ones.
2084 Even though our flight computers (except TeleMini v1.0) can store
2085 multiple flights, we strongly recommend downloading and saving
2086 flight data after each flight.
2090 <title>Ignite Mode</title>
2092 Instead of firing one charge at apogee and another charge at
2093 a fixed height above the ground, you can configure the
2094 altimeter to fire both at apogee or both during
2095 descent. This was added to support an airframe Bdale designed that
2096 had two altimeters, one in the fin can and one in the nose.
2099 Providing the ability to use both igniters for apogee or
2100 main allows some level of redundancy without needing two
2101 flight computers. In Redundant Apogee or Redundant Main
2102 mode, the two charges will be fired two seconds apart.
2106 <title>Pad Orientation</title>
2108 TeleMetrum and TeleMega measure acceleration along the axis
2109 of the board. Which way the board is oriented affects the
2110 sign of the acceleration value. Instead of trying to guess
2111 which way the board is mounted in the air frame, the
2112 altimeter must be explicitly configured for either Antenna
2113 Up or Antenna Down. The default, Antenna Up, expects the end
2114 of the board connected to the 70cm antenna to be nearest the
2115 nose of the rocket, with the end containing the screw
2116 terminals nearest the tail.
2120 <title>Configurable Pyro Channels</title>
2122 In addition to the usual Apogee and Main pyro channels,
2123 TeleMega has four additional channels that can be configured
2124 to activate when various flight conditions are
2125 satisfied. You can select as many conditions as necessary;
2126 all of them must be met in order to activate the
2127 channel. The conditions available are:
2132 Acceleration away from the ground. Select a value, and
2133 then choose whether acceleration should be above or
2134 below that value. Acceleration is positive upwards, so
2135 accelerating towards the ground would produce negative
2136 numbers. Acceleration during descent is noisy and
2137 inaccurate, so be careful when using it during these
2138 phases of the flight.
2143 Vertical speed. Select a value, and then choose whether
2144 vertical speed should be above or below that
2145 value. Speed is positive upwards, so moving towards the
2146 ground would produce negative numbers. Speed during
2147 descent is a bit noisy and so be careful when using it
2148 during these phases of the flight.
2153 Height. Select a value, and then choose whether the
2154 height above the launch pad should be above or below
2160 Orientation. TeleMega contains a 3-axis gyroscope and
2161 accelerometer which is used to measure the current
2162 angle. Note that this angle is not the change in angle
2163 from the launch pad, but rather absolute relative to
2164 gravity; the 3-axis accelerometer is used to compute the
2165 angle of the rocket on the launch pad and initialize the
2166 system. Because this value is computed by integrating
2167 rate gyros, it gets progressively less accurate as the
2168 flight goes on. It should have an accumulated error of
2169 less than 0.2°/second (after 10 seconds of flight, the
2170 error should be less than 2°).
2173 The usual use of the orientation configuration is to
2174 ensure that the rocket is traveling mostly upwards when
2175 deciding whether to ignite air starts or additional
2176 stages. For that, choose a reasonable maximum angle
2177 (like 20°) and set the motor igniter to require an angle
2178 of less than that value.
2183 Flight Time. Time since boost was detected. Select a
2184 value and choose whether to activate the pyro channel
2185 before or after that amount of time.
2190 Ascending. A simple test saying whether the rocket is
2191 going up or not. This is exactly equivalent to testing
2192 whether the speed is > 0.
2197 Descending. A simple test saying whether the rocket is
2198 going down or not. This is exactly equivalent to testing
2199 whether the speed is < 0.
2204 After Motor. The flight software counts each time the
2205 rocket starts accelerating (presumably due to a motor or
2206 motors igniting). Use this value to count ignitions for
2207 multi-staged or multi-airstart launches.
2212 Delay. This value doesn't perform any checks, instead it
2213 inserts a delay between the time when the other
2214 parameters become true and when the pyro channel is
2220 Flight State. The flight software tracks the flight
2221 through a sequence of states:
2225 Boost. The motor has lit and the rocket is
2226 accelerating upwards.
2231 Fast. The motor has burned out and the rocket is
2232 decelerating, but it is going faster than 200m/s.
2237 Coast. The rocket is still moving upwards and
2238 decelerating, but the speed is less than 200m/s.
2243 Drogue. The rocket has reached apogee and is heading
2244 back down, but is above the configured Main
2250 Main. The rocket is still descending, and is below
2256 Landed. The rocket is no longer moving.
2262 You can select a state to limit when the pyro channel
2263 may activate; note that the check is based on when the
2264 rocket transitions <emphasis>into</emphasis> the state, and so checking for
2265 “greater than Boost” means that the rocket is currently
2266 in boost or some later state.
2269 When a motor burns out, the rocket enters either Fast or
2270 Coast state (depending on how fast it is moving). If the
2271 computer detects upwards acceleration again, it will
2272 move back to Boost state.
2281 <title>AltosUI</title>
2285 <imagedata fileref="altosui.png" width="4.6in"/>
2290 The AltosUI program provides a graphical user interface for
2291 interacting with the Altus Metrum product family. AltosUI can
2292 monitor telemetry data, configure devices and many other
2293 tasks. The primary interface window provides a selection of
2294 buttons, one for each major activity in the system. This chapter
2295 is split into sections, each of which documents one of the tasks
2296 provided from the top-level toolbar.
2299 <title>Monitor Flight</title>
2300 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
2302 Selecting this item brings up a dialog box listing all of the
2303 connected TeleDongle devices. When you choose one of these,
2304 AltosUI will create a window to display telemetry data as
2305 received by the selected TeleDongle device.
2310 <imagedata fileref="device-selection.png" width="3.1in"/>
2315 All telemetry data received are automatically recorded in
2316 suitable log files. The name of the files includes the current
2317 date and rocket serial and flight numbers.
2320 The radio frequency being monitored by the TeleDongle device is
2321 displayed at the top of the window. You can configure the
2322 frequency by clicking on the frequency box and selecting the desired
2323 frequency. AltosUI remembers the last frequency selected for each
2324 TeleDongle and selects that automatically the next time you use
2328 Below the TeleDongle frequency selector, the window contains a few
2329 significant pieces of information about the altimeter providing
2330 the telemetry data stream:
2334 <para>The configured call-sign</para>
2337 <para>The device serial number</para>
2340 <para>The flight number. Each altimeter remembers how many
2346 The rocket flight state. Each flight passes through several
2347 states including Pad, Boost, Fast, Coast, Drogue, Main and
2353 The Received Signal Strength Indicator value. This lets
2354 you know how strong a signal TeleDongle is receiving. The
2355 radio inside TeleDongle operates down to about -99dBm;
2356 weaker signals may not be receivable. The packet link uses
2357 error detection and correction techniques which prevent
2358 incorrect data from being reported.
2363 The age of the displayed data, in seconds since the last
2364 successfully received telemetry packet. In normal operation
2365 this will stay in the low single digits. If the number starts
2366 counting up, then you are no longer receiving data over the radio
2367 link from the flight computer.
2372 Finally, the largest portion of the window contains a set of
2373 tabs, each of which contain some information about the rocket.
2374 They're arranged in 'flight order' so that as the flight
2375 progresses, the selected tab automatically switches to display
2376 data relevant to the current state of the flight. You can select
2377 other tabs at any time. The final 'table' tab displays all of
2378 the raw telemetry values in one place in a spreadsheet-like format.
2381 <title>Launch Pad</title>
2385 <imagedata fileref="launch-pad.png" width="5.5in"/>
2390 The 'Launch Pad' tab shows information used to decide when the
2391 rocket is ready for flight. The first elements include red/green
2392 indicators, if any of these is red, you'll want to evaluate
2393 whether the rocket is ready to launch:
2396 <term>Battery Voltage</term>
2399 This indicates whether the Li-Po battery powering the
2400 flight computer has sufficient charge to last for
2401 the duration of the flight. A value of more than
2402 3.8V is required for a 'GO' status.
2407 <term>Apogee Igniter Voltage</term>
2410 This indicates whether the apogee
2411 igniter has continuity. If the igniter has a low
2412 resistance, then the voltage measured here will be close
2413 to the Li-Po battery voltage. A value greater than 3.2V is
2414 required for a 'GO' status.
2419 <term>Main Igniter Voltage</term>
2422 This indicates whether the main
2423 igniter has continuity. If the igniter has a low
2424 resistance, then the voltage measured here will be close
2425 to the Li-Po battery voltage. A value greater than 3.2V is
2426 required for a 'GO' status.
2431 <term>On-board Data Logging</term>
2434 This indicates whether there is
2435 space remaining on-board to store flight data for the
2436 upcoming flight. If you've downloaded data, but failed
2437 to erase flights, there may not be any space
2438 left. Most of our flight computers can store multiple
2439 flights, depending on the configured maximum flight log
2440 size. TeleMini v1.0 stores only a single flight, so it
2442 downloaded and erased after each flight to capture
2443 data. This only affects on-board flight logging; the
2444 altimeter will still transmit telemetry and fire
2445 ejection charges at the proper times even if the flight
2446 data storage is full.
2451 <term>GPS Locked</term>
2454 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
2455 currently able to compute position information. GPS requires
2456 at least 4 satellites to compute an accurate position.
2461 <term>GPS Ready</term>
2464 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
2465 10 consecutive positions without losing lock. This ensures
2466 that the GPS receiver has reliable reception from the
2474 The Launchpad tab also shows the computed launch pad position
2475 and altitude, averaging many reported positions to improve the
2476 accuracy of the fix.
2480 <title>Ascent</title>
2484 <imagedata fileref="ascent.png" width="5.5in"/>
2489 This tab is shown during Boost, Fast and Coast
2490 phases. The information displayed here helps monitor the
2491 rocket as it heads towards apogee.
2494 The height, speed, acceleration and tilt are shown along
2495 with the maximum values for each of them. This allows you to
2496 quickly answer the most commonly asked questions you'll hear
2500 The current latitude and longitude reported by the GPS are
2501 also shown. Note that under high acceleration, these values
2502 may not get updated as the GPS receiver loses position
2503 fix. Once the rocket starts coasting, the receiver should
2504 start reporting position again.
2507 Finally, the current igniter voltages are reported as in the
2508 Launch Pad tab. This can help diagnose deployment failures
2509 caused by wiring which comes loose under high acceleration.
2513 <title>Descent</title>
2517 <imagedata fileref="descent.png" width="5.5in"/>
2522 Once the rocket has reached apogee and (we hope) activated the
2523 apogee charge, attention switches to tracking the rocket on
2524 the way back to the ground, and for dual-deploy flights,
2525 waiting for the main charge to fire.
2528 To monitor whether the apogee charge operated correctly, the
2529 current descent rate is reported along with the current
2530 height. Good descent rates vary based on the choice of recovery
2531 components, but generally range from 15-30m/s on drogue and should
2532 be below 10m/s when under the main parachute in a dual-deploy flight.
2535 With GPS-equipped flight computers, you can locate the rocket in the
2536 sky using the elevation and bearing information to figure
2537 out where to look. Elevation is in degrees above the
2538 horizon. Bearing is reported in degrees relative to true
2539 north. Range can help figure out how big the rocket will
2540 appear. Ground Distance shows how far it is to a point
2541 directly under the rocket and can help figure out where the
2542 rocket is likely to land. Note that all of these values are
2543 relative to the pad location. If the elevation is near 90°,
2544 the rocket is over the pad, not over you.
2547 Finally, the igniter voltages are reported in this tab as
2548 well, both to monitor the main charge as well as to see what
2549 the status of the apogee charge is. Note that some commercial
2550 e-matches are designed to retain continuity even after being
2551 fired, and will continue to show as green or return from red to
2556 <title>Landed</title>
2560 <imagedata fileref="landed.png" width="5.5in"/>
2565 Once the rocket is on the ground, attention switches to
2566 recovery. While the radio signal is often lost once the
2567 rocket is on the ground, the last reported GPS position is
2568 generally within a short distance of the actual landing location.
2571 The last reported GPS position is reported both by
2572 latitude and longitude as well as a bearing and distance from
2573 the launch pad. The distance should give you a good idea of
2574 whether to walk or hitch a ride. Take the reported
2575 latitude and longitude and enter them into your hand-held GPS
2576 unit and have that compute a track to the landing location.
2579 Our flight computers will continue to transmit RDF
2580 tones after landing, allowing you to locate the rocket by
2581 following the radio signal if necessary. You may need to get
2582 away from the clutter of the flight line, or even get up on
2583 a hill (or your neighbor's RV roof) to receive the RDF signal.
2586 The maximum height, speed and acceleration reported
2587 during the flight are displayed for your admiring observers.
2588 The accuracy of these immediate values depends on the quality
2589 of your radio link and how many packets were received.
2590 Recovering the on-board data after flight may yield
2591 more precise results.
2594 To get more detailed information about the flight, you can
2595 click on the 'Graph Flight' button which will bring up a
2596 graph window for the current flight.
2600 <title>Table</title>
2604 <imagedata fileref="table.png" width="5.5in"/>
2609 The table view shows all of the data available from the
2610 flight computer. Probably the most useful data on
2611 this tab is the detailed GPS information, which includes
2612 horizontal dilution of precision information, and
2613 information about the signal being received from the satellites.
2617 <title>Site Map</title>
2621 <imagedata fileref="site-map.png" width="5.5in"/>
2626 When the TeleMetrum has a GPS fix, the Site Map tab will map
2627 the rocket's position to make it easier for you to locate the
2628 rocket, both while it is in the air, and when it has landed. The
2629 rocket's state is indicated by color: white for pad, red for
2630 boost, pink for fast, yellow for coast, light blue for drogue,
2631 dark blue for main, and black for landed.
2634 The map's scale is approximately 3m (10ft) per pixel. The map
2635 can be dragged using the left mouse button. The map will attempt
2636 to keep the rocket roughly centered while data is being received.
2639 Images are fetched automatically via the Google Maps Static API,
2640 and cached on disk for reuse. If map images cannot be downloaded,
2641 the rocket's path will be traced on a dark gray background
2645 You can pre-load images for your favorite launch sites
2646 before you leave home; check out the 'Preload Maps' section below.
2651 <title>Save Flight Data</title>
2653 The altimeter records flight data to its internal flash memory.
2654 TeleMetrum data is recorded at a much higher rate than the telemetry
2655 system can handle, and is not subject to radio drop-outs. As
2656 such, it provides a more complete and precise record of the
2657 flight. The 'Save Flight Data' button allows you to read the
2658 flash memory and write it to disk.
2661 Clicking on the 'Save Flight Data' button brings up a list of
2662 connected flight computers and TeleDongle devices. If you select a
2663 flight computer, the flight data will be downloaded from that
2664 device directly. If you select a TeleDongle device, flight data
2665 will be downloaded from a flight computer over radio link via the
2666 specified TeleDongle. See the chapter on Controlling An Altimeter
2667 Over The Radio Link for more information.
2670 After the device has been selected, a dialog showing the
2671 flight data saved in the device will be shown allowing you to
2672 select which flights to download and which to delete. With
2673 version 0.9 or newer firmware, you must erase flights in order
2674 for the space they consume to be reused by another
2675 flight. This prevents accidentally losing flight data
2676 if you neglect to download data before flying again. Note that
2677 if there is no more space available in the device, then no
2678 data will be recorded during the next flight.
2681 The file name for each flight log is computed automatically
2682 from the recorded flight date, altimeter serial number and
2683 flight number information.
2687 <title>Replay Flight</title>
2689 Select this button and you are prompted to select a flight
2690 record file, either a .telem file recording telemetry data or a
2691 .eeprom file containing flight data saved from the altimeter
2695 Once a flight record is selected, the flight monitor interface
2696 is displayed and the flight is re-enacted in real time. Check
2697 the Monitor Flight chapter above to learn how this window operates.
2701 <title>Graph Data</title>
2703 Select this button and you are prompted to select a flight
2704 record file, either a .telem file recording telemetry data or a
2705 .eeprom file containing flight data saved from
2709 Note that telemetry files will generally produce poor graphs
2710 due to the lower sampling rate and missed telemetry packets.
2711 Use saved flight data in .eeprom files for graphing where possible.
2714 Once a flight record is selected, a window with multiple tabs is
2718 <title>Flight Graph</title>
2722 <imagedata fileref="graph.png" width="6in" scalefit="1"/>
2727 By default, the graph contains acceleration (blue),
2728 velocity (green) and altitude (red).
2731 The graph can be zoomed into a particular area by clicking and
2732 dragging down and to the right. Once zoomed, the graph can be
2733 reset by clicking and dragging up and to the left. Holding down
2734 control and clicking and dragging allows the graph to be panned.
2735 The right mouse button causes a pop-up menu to be displayed, giving
2736 you the option save or print the plot.
2740 <title>Configure Graph</title>
2744 <imagedata fileref="graph-configure.png" width="6in" scalefit="1"/>
2749 This selects which graph elements to show, and, at the
2750 very bottom, lets you switch between metric and
2755 <title>Flight Statistics</title>
2759 <imagedata fileref="graph-stats.png" width="6in" scalefit="1"/>
2764 Shows overall data computed from the flight.
2772 <imagedata fileref="graph-map.png" width="6in" scalefit="1"/>
2777 Shows a satellite image of the flight area overlaid
2778 with the path of the flight. The red concentric
2779 circles mark the launch pad, the black concentric
2780 circles mark the landing location.
2785 <title>Export Data</title>
2787 This tool takes the raw data files and makes them available for
2788 external analysis. When you select this button, you are prompted to
2789 select a flight data file, which can be either a .eeprom or .telem.
2790 The .eeprom files contain higher resolution and more continuous data,
2791 while .telem files contain receiver signal strength information.
2792 Next, a second dialog appears which is used to select
2793 where to write the resulting file. It has a selector to choose
2794 between CSV and KML file formats.
2797 <title>Comma Separated Value Format</title>
2799 This is a text file containing the data in a form suitable for
2800 import into a spreadsheet or other external data analysis
2801 tool. The first few lines of the file contain the version and
2802 configuration information from the altimeter, then
2803 there is a single header line which labels all of the
2804 fields. All of these lines start with a '#' character which
2805 many tools can be configured to skip over.
2808 The remaining lines of the file contain the data, with each
2809 field separated by a comma and at least one space. All of
2810 the sensor values are converted to standard units, with the
2811 barometric data reported in both pressure, altitude and
2812 height above pad units.
2816 <title>Keyhole Markup Language (for Google Earth)</title>
2818 This is the format used by Google Earth to provide an overlay
2819 within that application. With this, you can use Google Earth to
2820 see the whole flight path in 3D.
2825 <title>Configure Altimeter</title>
2829 <imagedata fileref="configure-altimeter.png" width="3.6in" scalefit="1"/>
2834 Select this button and then select either an altimeter or
2835 TeleDongle Device from the list provided. Selecting a TeleDongle
2836 device will use the radio link to configure a remote altimeter.
2839 The first few lines of the dialog provide information about the
2840 connected device, including the product name,
2841 software version and hardware serial number. Below that are the
2842 individual configuration entries.
2845 At the bottom of the dialog, there are four buttons:
2852 This writes any changes to the
2853 configuration parameter block in flash memory. If you don't
2854 press this button, any changes you make will be lost.
2862 This resets the dialog to the most recently saved values,
2863 erasing any changes you have made.
2871 This reboots the device. Use this to
2872 switch from idle to pad mode by rebooting once the rocket is
2873 oriented for flight, or to confirm changes you think you saved
2882 This closes the dialog. Any unsaved changes will be
2889 The rest of the dialog contains the parameters to be configured.
2892 <title>Main Deploy Altitude</title>
2894 This sets the altitude (above the recorded pad altitude) at
2895 which the 'main' igniter will fire. The drop-down menu shows
2896 some common values, but you can edit the text directly and
2897 choose whatever you like. If the apogee charge fires below
2898 this altitude, then the main charge will fire two seconds
2899 after the apogee charge fires.
2903 <title>Apogee Delay</title>
2905 When flying redundant electronics, it's often important to
2906 ensure that multiple apogee charges don't fire at precisely
2907 the same time, as that can over pressurize the apogee deployment
2908 bay and cause a structural failure of the air-frame. The Apogee
2909 Delay parameter tells the flight computer to fire the apogee
2910 charge a certain number of seconds after apogee has been
2915 <title>Radio Frequency</title>
2917 This configures which of the frequencies to use for both
2918 telemetry and packet command mode. Note that if you set this
2919 value via packet command mode, the TeleDongle frequency will
2920 also be automatically reconfigured to match so that
2921 communication will continue afterwards.
2925 <title>RF Calibration</title>
2927 The radios in every Altus Metrum device are calibrated at the
2928 factory to ensure that they transmit and receive on the
2929 specified frequency. If you need to you can adjust the calibration
2930 by changing this value. Do not do this without understanding what
2931 the value means, read the appendix on calibration and/or the source
2932 code for more information. To change a TeleDongle's calibration,
2933 you must reprogram the unit completely.
2937 <title>Telemetry/RDF/APRS Enable</title>
2939 Enables the radio for transmission during flight. When
2940 disabled, the radio will not transmit anything during flight
2945 <title>APRS Interval</title>
2947 How often to transmit GPS information via APRS (in
2948 seconds). When set to zero, APRS transmission is
2949 disabled. This option is available on TeleMetrum v2 and
2950 TeleMega boards. TeleMetrum v1 boards cannot transmit APRS
2951 packets. Note that a single APRS packet takes nearly a full
2952 second to transmit, so enabling this option will prevent
2953 sending any other telemetry during that time.
2957 <title>Callsign</title>
2959 This sets the call sign included in each telemetry packet. Set this
2960 as needed to conform to your local radio regulations.
2964 <title>Maximum Flight Log Size</title>
2966 This sets the space (in kilobytes) allocated for each flight
2967 log. The available space will be divided into chunks of this
2968 size. A smaller value will allow more flights to be stored,
2969 a larger value will record data from longer flights.
2973 <title>Ignite Mode</title>
2975 TeleMetrum and TeleMini provide two igniter channels as they
2976 were originally designed as dual-deploy flight
2977 computers. This configuration parameter allows the two
2978 channels to be used in different configurations.
2982 <term>Dual Deploy</term>
2985 This is the usual mode of operation; the
2986 'apogee' channel is fired at apogee and the 'main'
2987 channel at the height above ground specified by the
2988 'Main Deploy Altitude' during descent.
2993 <term>Redundant Apogee</term>
2996 This fires both channels at
2997 apogee, the 'apogee' channel first followed after a two second
2998 delay by the 'main' channel.
3003 <term>Redundant Main</term>
3006 This fires both channels at the
3007 height above ground specified by the Main Deploy
3008 Altitude setting during descent. The 'apogee'
3009 channel is fired first, followed after a two second
3010 delay by the 'main' channel.
3017 <title>Pad Orientation</title>
3019 Because they include accelerometers, TeleMetrum and
3020 TeleMega are sensitive to the orientation of the board. By
3021 default, they expect the antenna end to point forward. This
3022 parameter allows that default to be changed, permitting the
3023 board to be mounted with the antenna pointing aft instead.
3027 <term>Antenna Up</term>
3030 In this mode, the antenna end of the
3031 flight computer must point forward, in line with the
3032 expected flight path.
3037 <term>Antenna Down</term>
3040 In this mode, the antenna end of the
3041 flight computer must point aft, in line with the
3042 expected flight path.
3049 <title>Configure Pyro Channels</title>
3053 <imagedata fileref="configure-pyro.png" width="6in" scalefit="1"/>
3058 This opens a separate window to configure the additional
3059 pyro channels available on TeleMega. One column is
3060 presented for each channel. Each row represents a single
3061 parameter, if enabled the parameter must meet the specified
3062 test for the pyro channel to be fired. See the Pyro Channels
3063 section in the System Operation chapter above for a
3064 description of these parameters.
3067 Select conditions and set the related value; the pyro
3068 channel will be activated when <emphasis>all</emphasis> of the
3069 conditions are met. Each pyro channel has a separate set of
3070 configuration values, so you can use different values for
3071 the same condition with different channels.
3074 Once you have selected the appropriate configuration for all
3075 of the necessary pyro channels, you can save the pyro
3076 configuration along with the rest of the flight computer
3077 configuration by pressing the 'Save' button in the main
3078 Configure Flight Computer window.
3083 <title>Configure AltosUI</title>
3087 <imagedata fileref="configure-altosui.png" width="2.4in" scalefit="1"/>
3092 This button presents a dialog so that you can configure the AltosUI global settings.
3095 <title>Voice Settings</title>
3097 AltosUI provides voice announcements during flight so that you
3098 can keep your eyes on the sky and still get information about
3099 the current flight status. However, sometimes you don't want
3106 <para>Turns all voice announcements on and off</para>
3110 <term>Test Voice</term>
3113 Plays a short message allowing you to verify
3114 that the audio system is working and the volume settings
3122 <title>Log Directory</title>
3124 AltosUI logs all telemetry data and saves all TeleMetrum flash
3125 data to this directory. This directory is also used as the
3126 staring point when selecting data files for display or export.
3129 Click on the directory name to bring up a directory choosing
3130 dialog, select a new directory and click 'Select Directory' to
3131 change where AltosUI reads and writes data files.
3135 <title>Callsign</title>
3137 This value is transmitted in each command packet sent from
3138 TeleDongle and received from an altimeter. It is not used in
3139 telemetry mode, as the callsign configured in the altimeter board
3140 is included in all telemetry packets. Configure this
3141 with the AltosUI operators call sign as needed to comply with
3142 your local radio regulations.
3145 Note that to successfully command a flight computer over the radio
3146 (to configure the altimeter, monitor idle, or fire pyro charges),
3147 the callsign configured here must exactly match the callsign
3148 configured in the flight computer. This matching is case
3153 <title>Imperial Units</title>
3155 This switches between metric units (meters) and imperial
3156 units (feet and miles). This affects the display of values
3157 use during flight monitoring, configuration, data graphing
3158 and all of the voice announcements. It does not change the
3159 units used when exporting to CSV files, those are always
3160 produced in metric units.
3164 <title>Font Size</title>
3166 Selects the set of fonts used in the flight monitor
3167 window. Choose between the small, medium and large sets.
3171 <title>Serial Debug</title>
3173 This causes all communication with a connected device to be
3174 dumped to the console from which AltosUI was started. If
3175 you've started it from an icon or menu entry, the output
3176 will simply be discarded. This mode can be useful to debug
3177 various serial communication issues.
3181 <title>Manage Frequencies</title>
3183 This brings up a dialog where you can configure the set of
3184 frequencies shown in the various frequency menus. You can
3185 add as many as you like, or even reconfigure the default
3186 set. Changing this list does not affect the frequency
3187 settings of any devices, it only changes the set of
3188 frequencies shown in the menus.
3193 <title>Configure Groundstation</title>
3197 <imagedata fileref="configure-groundstation.png" width="3.1in" scalefit="1"/>
3202 Select this button and then select a TeleDongle Device from the list provided.
3205 The first few lines of the dialog provide information about the
3206 connected device, including the product name,
3207 software version and hardware serial number. Below that are the
3208 individual configuration entries.
3211 Note that the TeleDongle itself doesn't save any configuration
3212 data, the settings here are recorded on the local machine in
3213 the Java preferences database. Moving the TeleDongle to
3214 another machine, or using a different user account on the same
3215 machine will cause settings made here to have no effect.
3218 At the bottom of the dialog, there are three buttons:
3225 This writes any changes to the
3226 local Java preferences file. If you don't
3227 press this button, any changes you make will be lost.
3235 This resets the dialog to the most recently saved values,
3236 erasing any changes you have made.
3244 This closes the dialog. Any unsaved changes will be
3251 The rest of the dialog contains the parameters to be configured.
3254 <title>Frequency</title>
3256 This configures the frequency to use for both telemetry and
3257 packet command mode. Set this before starting any operation
3258 involving packet command mode so that it will use the right
3259 frequency. Telemetry monitoring mode also provides a menu to
3260 change the frequency, and that menu also sets the same Java
3261 preference value used here.
3265 <title>Radio Calibration</title>
3267 The radios in every Altus Metrum device are calibrated at the
3268 factory to ensure that they transmit and receive on the
3269 specified frequency. To change a TeleDongle's calibration,
3270 you must reprogram the unit completely, so this entry simply
3271 shows the current value and doesn't allow any changes.
3276 <title>Flash Image</title>
3278 This reprograms Altus Metrum devices with new
3279 firmware. TeleMetrum v1.x, TeleDongle, TeleMini and TeleBT are
3280 all reprogrammed by using another similar unit as a
3281 programming dongle (pair programming). TeleMega, TeleMetrum v2
3282 and EasyMini are all programmed directly over their USB ports
3283 (self programming). Please read the directions for flashing
3284 devices in the Updating Device Firmware chapter below.
3288 <title>Fire Igniter</title>
3292 <imagedata fileref="fire-igniter.png" width="1.2in" scalefit="1"/>
3297 This activates the igniter circuits in the flight computer to help
3298 test recovery systems deployment. Because this command can operate
3299 over the Packet Command Link, you can prepare the rocket as
3300 for flight and then test the recovery system without needing
3301 to snake wires inside the air-frame.
3304 Selecting the 'Fire Igniter' button brings up the usual device
3305 selection dialog. Pick the desired device. This brings up another
3306 window which shows the current continuity test status for all
3307 of the pyro channels.
3310 Next, select the desired igniter to fire. This will enable the
3314 Select the 'Arm' button. This enables the 'Fire' button. The
3315 word 'Arm' is replaced by a countdown timer indicating that
3316 you have 10 seconds to press the 'Fire' button or the system
3317 will deactivate, at which point you start over again at
3318 selecting the desired igniter.
3322 <title>Scan Channels</title>
3326 <imagedata fileref="scan-channels.png" width="3.2in" scalefit="1"/>
3331 This listens for telemetry packets on all of the configured
3332 frequencies, displaying information about each device it
3333 receives a packet from. You can select which of the three
3334 telemetry formats should be tried; by default, it only listens
3335 for the standard telemetry packets used in v1.0 and later
3340 <title>Load Maps</title>
3344 <imagedata fileref="load-maps.png" width="5.2in" scalefit="1"/>
3349 Before heading out to a new launch site, you can use this to
3350 load satellite images in case you don't have internet
3351 connectivity at the site. This loads a fairly large area
3352 around the launch site, which should cover any flight you're likely to make.
3355 There's a drop-down menu of launch sites we know about; if
3356 your favorites aren't there, please let us know the lat/lon
3357 and name of the site. The contents of this list are actually
3358 downloaded from our server at run-time, so as new sites are sent
3359 in, they'll get automatically added to this list.
3362 If the launch site isn't in the list, you can manually enter the lat/lon values
3365 Clicking the 'Load Map' button will fetch images from Google
3366 Maps; note that Google limits how many images you can fetch at
3367 once, so if you load more than one launch site, you may get
3368 some gray areas in the map which indicate that Google is tired
3369 of sending data to you. Try again later.
3373 <title>Monitor Idle</title>
3375 This brings up a dialog similar to the Monitor Flight UI,
3376 except it works with the altimeter in “idle” mode by sending
3377 query commands to discover the current state rather than
3378 listening for telemetry packets. Because this uses command
3379 mode, it needs to have the TeleDongle and flight computer
3380 callsigns match exactly. If you can receive telemetry, but
3381 cannot manage to run Monitor Idle, then it's very likely that
3382 your callsigns are different in some way.
3387 <title>AltosDroid</title>
3389 AltosDroid provides the same flight monitoring capabilities as
3390 AltosUI, but runs on Android devices and is designed to connect
3391 to a TeleBT receiver over Bluetooth™. AltosDroid monitors
3392 telemetry data, logging it to internal storage in the Android
3393 device, and presents that data in a UI the same way the 'Monitor
3394 Flight' window does in AltosUI.
3397 This manual will explain how to configure AltosDroid, connect
3398 to TeleBT, operate the flight monitoring interface and describe
3399 what the displayed data means.
3402 <title>Installing AltosDroid</title>
3404 AltosDroid is available from the Google Play store. To install
3405 it on your Android device, open the Google Play Store
3406 application and search for “altosdroid”. Make sure you don't
3407 have a space between “altos” and “droid” or you probably won't
3408 find what you want. That should bring you to the right page
3409 from which you can download and install the application.
3413 <title>Connecting to TeleBT</title>
3415 Press the Android 'Menu' button or soft-key to see the
3416 configuration options available. Select the 'Connect a device'
3417 option and then the 'Scan for devices' entry at the bottom to
3418 look for your TeleBT device. Select your device, and when it
3419 asks for the code, enter '1234'.
3422 Subsequent connections will not require you to enter that
3423 code, and your 'paired' device will appear in the list without
3428 <title>Configuring AltosDroid</title>
3430 The only configuration option available for AltosDroid is
3431 which frequency to listen on. Press the Android 'Menu' button
3432 or soft-key and pick the 'Select radio frequency' entry. That
3433 brings up a menu of pre-set radio frequencies; pick the one
3434 which matches your altimeter.
3438 <title>AltosDroid Flight Monitoring</title>
3440 AltosDroid is designed to mimic the AltosUI flight monitoring
3441 display, providing separate tabs for each stage of your rocket
3442 flight along with a tab containing a map of the local area
3443 with icons marking the current location of the altimeter and
3449 The 'Launch Pad' tab shows information used to decide when the
3450 rocket is ready for flight. The first elements include red/green
3451 indicators, if any of these is red, you'll want to evaluate
3452 whether the rocket is ready to launch:
3455 <term>Battery Voltage</term>
3458 This indicates whether the Li-Po battery
3459 powering the TeleMetrum has sufficient charge to last for
3460 the duration of the flight. A value of more than
3461 3.8V is required for a 'GO' status.
3466 <term>Apogee Igniter Voltage</term>
3469 This indicates whether the apogee
3470 igniter has continuity. If the igniter has a low
3471 resistance, then the voltage measured here will be close
3472 to the Li-Po battery voltage. A value greater than 3.2V is
3473 required for a 'GO' status.
3478 <term>Main Igniter Voltage</term>
3481 This indicates whether the main
3482 igniter has continuity. If the igniter has a low
3483 resistance, then the voltage measured here will be close
3484 to the Li-Po battery voltage. A value greater than 3.2V is
3485 required for a 'GO' status.
3490 <term>On-board Data Logging</term>
3493 This indicates whether there is
3494 space remaining on-board to store flight data for the
3495 upcoming flight. If you've downloaded data, but failed
3496 to erase flights, there may not be any space
3497 left. TeleMetrum can store multiple flights, depending
3498 on the configured maximum flight log size. TeleMini
3499 stores only a single flight, so it will need to be
3500 downloaded and erased after each flight to capture
3501 data. This only affects on-board flight logging; the
3502 altimeter will still transmit telemetry and fire
3503 ejection charges at the proper times.
3508 <term>GPS Locked</term>
3511 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
3512 currently able to compute position information. GPS requires
3513 at least 4 satellites to compute an accurate position.
3518 <term>GPS Ready</term>
3521 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
3522 10 consecutive positions without losing lock. This ensures
3523 that the GPS receiver has reliable reception from the
3531 The Launchpad tab also shows the computed launch pad position
3532 and altitude, averaging many reported positions to improve the
3533 accuracy of the fix.
3538 <title>Downloading Flight Logs</title>
3540 AltosDroid always saves every bit of telemetry data it
3541 receives. To download that to a computer for use with AltosUI,
3542 simply remove the SD card from your Android device, or connect
3543 your device to your computer's USB port and browse the files
3544 on that device. You will find '.telem' files in the TeleMetrum
3545 directory that will work with AltosUI directly.
3550 <title>Using Altus Metrum Products</title>
3552 <title>Being Legal</title>
3554 First off, in the US, you need an <ulink url="http://www.altusmetrum.org/Radio/">amateur radio license</ulink> or
3555 other authorization to legally operate the radio transmitters that are part
3560 <title>In the Rocket</title>
3562 In the rocket itself, you just need a flight computer and
3563 a single-cell, 3.7 volt nominal Li-Po rechargeable battery. An
3564 850mAh battery weighs less than a 9V alkaline battery, and will
3565 run a TeleMetrum or TeleMega for hours.
3566 A 110mAh battery weighs less than a triple A battery and is a good
3567 choice for use with TeleMini.
3570 By default, we ship flight computers with a simple wire antenna.
3571 If your electronics bay or the air-frame it resides within is made
3572 of carbon fiber, which is opaque to RF signals, you may prefer to
3573 install an SMA connector so that you can run a coaxial cable to an
3574 antenna mounted elsewhere in the rocket. However, note that the
3575 GPS antenna is fixed on all current products, so you really want
3576 to install the flight computer in a bay made of RF-transparent
3577 materials if at all possible.
3581 <title>On the Ground</title>
3583 To receive the data stream from the rocket, you need an antenna and short
3584 feed-line connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. If possible, use an SMA to BNC
3585 adapter instead of feedline between the antenna feedpoint and
3586 TeleDongle, as this will give you the best performance. The
3587 TeleDongle in turn plugs directly into the USB port on a notebook
3588 computer. Because TeleDongle looks like a simple serial port, your computer
3589 does not require special device drivers... just plug it in.
3592 The GUI tool, AltosUI, is written in Java and runs across
3593 Linux, Mac OS and Windows. There's also a suite of C tools
3594 for Linux which can perform most of the same tasks.
3597 Alternatively, a TeleBT attached with an SMA to BNC adapter at the
3598 feed point of a hand-held yagi used in conjunction with an Android
3599 device running AltosDroid makes an outstanding ground station.
3602 After the flight, you can use the radio link to extract the more detailed data
3603 logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
3604 TeleMetrum board directly. Pulling out the data without having to open up
3605 the rocket is pretty cool! A USB cable is also how you charge the Li-Po
3606 battery, so you'll want one of those anyway... the same cable used by lots
3607 of digital cameras and other modern electronic stuff will work fine.
3610 If your rocket lands out of sight, you may enjoy having a hand-held
3611 GPS receiver, so that you can put in a way-point for the last
3612 reported rocket position before touch-down. This makes looking for
3613 your rocket a lot like Geo-Caching... just go to the way-point and
3614 look around starting from there. AltosDroid on an Android device
3615 with GPS receiver works great for this, too!
3618 You may also enjoy having a ham radio “HT” that covers the 70cm band... you
3619 can use that with your antenna to direction-find the rocket on the ground
3620 the same way you can use a Walston or Beeline tracker. This can be handy
3621 if the rocket is hiding in sage brush or a tree, or if the last GPS position
3622 doesn't get you close enough because the rocket dropped into a canyon, or
3623 the wind is blowing it across a dry lake bed, or something like that... Keith
3624 currently uses a Yaesu VX-7R, Bdale has a Baofung UV-5R
3625 which isn't as nice, but was a whole lot cheaper.
3628 So, to recap, on the ground the hardware you'll need includes:
3629 <orderedlist inheritnum='inherit' numeration='arabic'>
3632 an antenna and feed-line or adapter
3647 optionally, a hand-held GPS receiver
3652 optionally, an HT or receiver covering 435 MHz
3658 The best hand-held commercial directional antennas we've found for radio
3659 direction finding rockets are from
3660 <ulink url="http://www.arrowantennas.com/" >
3663 The 440-3 and 440-5 are both good choices for finding a
3664 TeleMetrum- or TeleMini- equipped rocket when used with a suitable
3665 70cm HT. TeleDongle and an SMA to BNC adapter fit perfectly
3666 between the driven element and reflector of Arrow antennas.
3670 <title>Data Analysis</title>
3672 Our software makes it easy to log the data from each flight, both the
3673 telemetry received during the flight itself, and the more
3674 complete data log recorded in the flash memory on the altimeter
3675 board. Once this data is on your computer, our post-flight tools make it
3676 easy to quickly get to the numbers everyone wants, like apogee altitude,
3677 max acceleration, and max velocity. You can also generate and view a
3678 standard set of plots showing the altitude, acceleration, and
3679 velocity of the rocket during flight. And you can even export a TeleMetrum data file
3680 usable with Google Maps and Google Earth for visualizing the flight path
3681 in two or three dimensions!
3684 Our ultimate goal is to emit a set of files for each flight that can be
3685 published as a web page per flight, or just viewed on your local disk with
3690 <title>Future Plans</title>
3692 We've designed a simple GPS based radio tracker called TeleGPS.
3693 If all goes well, we hope to introduce this in the first
3697 We have designed and prototyped several “companion boards” that
3698 can attach to the companion connector on TeleMetrum and TeleMega
3699 flight computers to collect more data, provide more pyro channels,
3700 and so forth. We do not yet know if or when any of these boards
3701 will be produced in enough quantity to sell. If you have specific
3702 interests for data collection or control of events in your rockets
3703 beyond the capabilities of our existing productions, please let
3707 Because all of our work is open, both the hardware designs and the
3708 software, if you have some great idea for an addition to the current
3709 Altus Metrum family, feel free to dive in and help! Or let us know
3710 what you'd like to see that we aren't already working on, and maybe
3711 we'll get excited about it too...
3715 <ulink url="http://altusmetrum.org/">web site</ulink> for more news
3716 and information as our family of products evolves!
3721 <title>Altimeter Installation Recommendations</title>
3723 Building high-power rockets that fly safely is hard enough. Mix
3724 in some sophisticated electronics and a bunch of radio energy
3725 and some creativity and/or compromise may be required. This chapter
3726 contains some suggestions about how to install Altus Metrum
3727 products into a rocket air-frame, including how to safely and
3728 reliably mix a variety of electronics into the same air-frame.
3731 <title>Mounting the Altimeter</title>
3733 The first consideration is to ensure that the altimeter is
3734 securely fastened to the air-frame. For most of our products, we
3735 prefer nylon standoffs and nylon screws; they're good to at least 50G
3736 and cannot cause any electrical issues on the board. Metal screws
3737 and standoffs are fine, too, just be careful to avoid electrical
3738 shorts! For TeleMini v1.0, we usually cut small pieces of 1/16 inch
3740 under the screw holes, and then take 2x56 nylon screws and
3741 screw them through the TeleMini mounting holes, through the
3742 balsa and into the underlying material.
3744 <orderedlist inheritnum='inherit' numeration='arabic'>
3747 Make sure accelerometer-equipped products like TeleMetrum and
3748 TeleMega are aligned precisely along the axis of
3749 acceleration so that the accelerometer can accurately
3750 capture data during the flight.
3755 Watch for any metal touching components on the
3756 board. Shorting out connections on the bottom of the board
3757 can cause the altimeter to fail during flight.
3763 <title>Dealing with the Antenna</title>
3765 The antenna supplied is just a piece of solid, insulated,
3766 wire. If it gets damaged or broken, it can be easily
3767 replaced. It should be kept straight and not cut; bending or
3768 cutting it will change the resonant frequency and/or
3769 impedance, making it a less efficient radiator and thus
3770 reducing the range of the telemetry signal.
3773 Keeping metal away from the antenna will provide better range
3774 and a more even radiation pattern. In most rockets, it's not
3775 entirely possible to isolate the antenna from metal
3776 components; there are often bolts, all-thread and wires from other
3777 electronics to contend with. Just be aware that the more stuff
3778 like this around the antenna, the lower the range.
3781 Make sure the antenna is not inside a tube made or covered
3782 with conducting material. Carbon fiber is the most common
3783 culprit here -- CF is a good conductor and will effectively
3784 shield the antenna, dramatically reducing signal strength and
3785 range. Metallic flake paint is another effective shielding
3786 material which should be avoided around any antennas.
3789 If the ebay is large enough, it can be convenient to simply
3790 mount the altimeter at one end and stretch the antenna out
3791 inside. Taping the antenna to the sled can keep it straight
3792 under acceleration. If there are metal rods, keep the
3793 antenna as far away as possible.
3796 For a shorter ebay, it's quite practical to have the antenna
3797 run through a bulkhead and into an adjacent bay. Drill a small
3798 hole in the bulkhead, pass the antenna wire through it and
3799 then seal it up with glue or clay. We've also used acrylic
3800 tubing to create a cavity for the antenna wire. This works a
3801 bit better in that the antenna is known to stay straight and
3802 not get folded by recovery components in the bay. Angle the
3803 tubing towards the side wall of the rocket and it ends up
3804 consuming very little space.
3807 If you need to place the UHF antenna at a distance from the
3808 altimeter, you can replace the antenna with an edge-mounted
3809 SMA connector, and then run 50Ω coax from the board to the
3810 antenna. Building a remote antenna is beyond the scope of this
3815 <title>Preserving GPS Reception</title>
3817 The GPS antenna and receiver used in TeleMetrum and TeleMega is
3818 highly sensitive and normally have no trouble tracking enough
3819 satellites to provide accurate position information for
3820 recovering the rocket. However, there are many ways the GPS signal
3821 can end up attenuated, negatively affecting GPS performance.
3822 <orderedlist inheritnum='inherit' numeration='arabic'>
3825 Conductive tubing or coatings. Carbon fiber and metal
3826 tubing, or metallic paint will all dramatically attenuate the
3827 GPS signal. We've never heard of anyone successfully
3828 receiving GPS from inside these materials.
3833 Metal components near the GPS patch antenna. These will
3834 de-tune the patch antenna, changing the resonant frequency
3835 away from the L1 carrier and reduce the effectiveness of the
3836 antenna. You can place as much stuff as you like beneath the
3837 antenna as that's covered with a ground plane. But, keep
3838 wires and metal out from above the patch antenna.
3845 <title>Radio Frequency Interference</title>
3847 Any altimeter will generate RFI; the digital circuits use
3848 high-frequency clocks that spray radio interference across a
3849 wide band. Altus Metrum altimeters generate intentional radio
3850 signals as well, increasing the amount of RF energy around the board.
3853 Rocketry altimeters also use precise sensors measuring air
3854 pressure and acceleration. Tiny changes in voltage can cause
3855 these sensor readings to vary by a huge amount. When the
3856 sensors start mis-reporting data, the altimeter can either
3857 fire the igniters at the wrong time, or not fire them at all.
3860 Voltages are induced when radio frequency energy is
3861 transmitted from one circuit to another. Here are things that
3862 influence the induced voltage and current:
3867 Keep wires from different circuits apart. Moving circuits
3868 further apart will reduce RFI.
3873 Avoid parallel wires from different circuits. The longer two
3874 wires run parallel to one another, the larger the amount of
3875 transferred energy. Cross wires at right angles to reduce
3881 Twist wires from the same circuits. Two wires the same
3882 distance from the transmitter will get the same amount of
3883 induced energy which will then cancel out. Any time you have
3884 a wire pair running together, twist the pair together to
3885 even out distances and reduce RFI. For altimeters, this
3886 includes battery leads, switch hookups and igniter
3892 Avoid resonant lengths. Know what frequencies are present
3893 in the environment and avoid having wire lengths near a
3894 natural resonant length. Altus Metrum products transmit on the
3895 70cm amateur band, so you should avoid lengths that are a
3896 simple ratio of that length; essentially any multiple of ¼
3897 of the wavelength (17.5cm).
3903 <title>The Barometric Sensor</title>
3905 Altusmetrum altimeters measure altitude with a barometric
3906 sensor, essentially measuring the amount of air above the
3907 rocket to figure out how high it is. A large number of
3908 measurements are taken as the altimeter initializes itself to
3909 figure out the pad altitude. Subsequent measurements are then
3910 used to compute the height above the pad.
3913 To accurately measure atmospheric pressure, the ebay
3914 containing the altimeter must be vented outside the
3915 air-frame. The vent must be placed in a region of linear
3916 airflow, have smooth edges, and away from areas of increasing or
3917 decreasing pressure.
3920 All barometric sensors are quite sensitive to chemical damage from
3921 the products of APCP or BP combustion, so make sure the ebay is
3922 carefully sealed from any compartment which contains ejection
3927 <title>Ground Testing</title>
3929 The most important aspect of any installation is careful
3930 ground testing. Bringing an air-frame up to the LCO table which
3931 hasn't been ground tested can lead to delays or ejection
3932 charges firing on the pad, or, even worse, a recovery system
3936 Do a 'full systems' test that includes wiring up all igniters
3937 without any BP and turning on all of the electronics in flight
3938 mode. This will catch any mistakes in wiring and any residual
3939 RFI issues that might accidentally fire igniters at the wrong
3940 time. Let the air-frame sit for several minutes, checking for
3941 adequate telemetry signal strength and GPS lock. If any igniters
3942 fire unexpectedly, find and resolve the issue before loading any
3946 Ground test the ejection charges. Prepare the rocket for
3947 flight, loading ejection charges and igniters. Completely
3948 assemble the air-frame and then use the 'Fire Igniters'
3949 interface through a TeleDongle to command each charge to
3950 fire. Make sure the charge is sufficient to robustly separate
3951 the air-frame and deploy the recovery system.
3956 <title>Updating Device Firmware</title>
3958 TeleMega, TeleMetrum v2 and EasyMini are all programmed directly
3959 over their USB connectors (self programming). TeleMetrum v1, TeleMini and
3960 TeleDongle are all programmed by using another device as a
3961 programmer (pair programming). It's important to recognize which
3962 kind of devices you have before trying to reprogram them.
3965 You may wish to begin by ensuring you have current firmware images.
3966 These are distributed as part of the AltOS software bundle that
3967 also includes the AltosUI ground station program. Newer ground
3968 station versions typically work fine with older firmware versions,
3969 so you don't need to update your devices just to try out new
3970 software features. You can always download the most recent
3971 version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
3974 If you need to update the firmware on a TeleDongle, we recommend
3975 updating the altimeter first, before updating TeleDongle. However,
3976 note that TeleDongle rarely need to be updated. Any firmware version
3977 1.0.1 or later will work, version 1.2.1 may have improved receiver
3978 performance slightly.
3981 Self-programmable devices (TeleMega, TeleMetrum v2 and EasyMini)
3982 are reprogrammed by connecting them to your computer over USB
3986 Updating TeleMega, TeleMetrum v2 or EasyMini Firmware
3988 <orderedlist inheritnum='inherit' numeration='arabic'>
3991 Attach a battery and power switch to the target
3992 device. Power up the device.
3997 Using a Micro USB cable, connect the target device to your
3998 computer's USB socket.
4003 Run AltosUI, and select 'Flash Image' from the File menu.
4008 Select the target device in the Device Selection dialog.
4013 Select the image you want to flash to the device, which
4014 should have a name in the form
4015 <product>-v<product-version>-<software-version>.ihx, such
4016 as TeleMega-v1.0-1.3.0.ihx.
4021 Make sure the configuration parameters are reasonable
4022 looking. If the serial number and/or RF configuration
4023 values aren't right, you'll need to change them.
4028 Hit the 'OK' button and the software should proceed to flash
4029 the device with new firmware, showing a progress bar.
4034 Verify that the device is working by using the 'Configure
4035 Altimeter' item to check over the configuration.
4040 <title>Recovering From Self-Flashing Failure</title>
4042 If the firmware loading fails, it can leave the device
4043 unable to boot. Not to worry, you can force the device to
4044 start the boot loader instead, which will let you try to
4045 flash the device again.
4048 On each device, connecting two pins from one of the exposed
4049 connectors will force the boot loader to start, even if the
4050 regular operating system has been corrupted in some way.
4054 <term>TeleMega</term>
4057 Connect pin 6 and pin 1 of the companion connector. Pin 1
4058 can be identified by the square pad around it, and then
4059 the pins could sequentially across the board. Be very
4060 careful to <emphasis>not</emphasis> short pin 8 to
4061 anything as that is connected directly to the battery. Pin
4062 7 carries 3.3V and the board will crash if that is
4063 connected to pin 1, but shouldn't damage the board.
4068 <term>TeleMetrum v2</term>
4071 Connect pin 6 and pin 1 of the companion connector. Pin 1
4072 can be identified by the square pad around it, and then
4073 the pins could sequentially across the board. Be very
4074 careful to <emphasis>not</emphasis> short pin 8 to
4075 anything as that is connected directly to the battery. Pin
4076 7 carries 3.3V and the board will crash if that is
4077 connected to pin 1, but shouldn't damage the board.
4082 <term>EasyMini</term>
4085 Connect pin 6 and pin 1 of the debug connector, which is
4086 the six holes next to the beeper. Pin 1 can be identified
4087 by the square pad around it, and then the pins could
4088 sequentially across the board, making Pin 6 the one on the
4089 other end of the row.
4097 <title>Pair Programming</title>
4099 The big concept to understand is that you have to use a
4100 TeleMega, TeleMetrum or TeleDongle as a programmer to update a
4101 pair programmed device. Due to limited memory resources in the
4102 cc1111, we don't support programming directly over USB for these
4107 <title>Updating TeleMetrum v1.x Firmware</title>
4108 <orderedlist inheritnum='inherit' numeration='arabic'>
4111 Find the 'programming cable' that you got as part of the starter
4112 kit, that has a red 8-pin MicroMaTch connector on one end and a
4113 red 4-pin MicroMaTch connector on the other end.
4118 Take the 2 screws out of the TeleDongle case to get access
4119 to the circuit board.
4124 Plug the 8-pin end of the programming cable to the
4125 matching connector on the TeleDongle, and the 4-pin end to the
4126 matching connector on the TeleMetrum.
4127 Note that each MicroMaTch connector has an alignment pin that
4128 goes through a hole in the PC board when you have the cable
4134 Attach a battery to the TeleMetrum board.
4139 Plug the TeleDongle into your computer's USB port, and power
4145 Run AltosUI, and select 'Flash Image' from the File menu.
4150 Pick the TeleDongle device from the list, identifying it as the
4156 Select the image you want put on the TeleMetrum, which should have a
4157 name in the form telemetrum-v1.2-1.0.0.ihx. It should be visible
4158 in the default directory, if not you may have to poke around
4159 your system to find it.
4164 Make sure the configuration parameters are reasonable
4165 looking. If the serial number and/or RF configuration
4166 values aren't right, you'll need to change them.
4171 Hit the 'OK' button and the software should proceed to flash
4172 the TeleMetrum with new firmware, showing a progress bar.
4177 Confirm that the TeleMetrum board seems to have updated OK, which you
4178 can do by plugging in to it over USB and using a terminal program
4179 to connect to the board and issue the 'v' command to check
4185 If something goes wrong, give it another try.
4191 <title>Updating TeleMini Firmware</title>
4192 <orderedlist inheritnum='inherit' numeration='arabic'>
4195 You'll need a special 'programming cable' to reprogram the
4196 TeleMini. You can make your own using an 8-pin MicroMaTch
4197 connector on one end and a set of four pins on the other.
4202 Take the 2 screws out of the TeleDongle case to get access
4203 to the circuit board.
4208 Plug the 8-pin end of the programming cable to the matching
4209 connector on the TeleDongle, and the 4-pins into the holes
4210 in the TeleMini circuit board. Note that the MicroMaTch
4211 connector has an alignment pin that goes through a hole in
4212 the PC board when you have the cable oriented correctly, and
4213 that pin 1 on the TeleMini board is marked with a square pad
4214 while the other pins have round pads.
4219 Attach a battery to the TeleMini board.
4224 Plug the TeleDongle into your computer's USB port, and power
4230 Run AltosUI, and select 'Flash Image' from the File menu.
4235 Pick the TeleDongle device from the list, identifying it as the
4241 Select the image you want put on the TeleMini, which should have a
4242 name in the form telemini-v1.0-1.0.0.ihx. It should be visible
4243 in the default directory, if not you may have to poke around
4244 your system to find it.
4249 Make sure the configuration parameters are reasonable
4250 looking. If the serial number and/or RF configuration
4251 values aren't right, you'll need to change them.
4256 Hit the 'OK' button and the software should proceed to flash
4257 the TeleMini with new firmware, showing a progress bar.
4262 Confirm that the TeleMini board seems to have updated OK, which you
4263 can do by configuring it over the radio link through the TeleDongle, or
4264 letting it come up in “flight” mode and listening for telemetry.
4269 If something goes wrong, give it another try.
4275 <title>Updating TeleDongle Firmware</title>
4277 Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
4278 firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
4280 <orderedlist inheritnum='inherit' numeration='arabic'>
4283 Find the 'programming cable' that you got as part of the starter
4284 kit, that has a red 8-pin MicroMaTch connector on one end and a
4285 red 4-pin MicroMaTch connector on the other end.
4290 Find the USB cable that you got as part of the starter kit, and
4291 plug the “mini” end in to the mating connector on TeleMetrum or TeleDongle.
4296 Take the 2 screws out of the TeleDongle case to get access
4297 to the circuit board.
4302 Plug the 8-pin end of the programming cable to the
4303 matching connector on the programmer, and the 4-pin end to the
4304 matching connector on the TeleDongle.
4305 Note that each MicroMaTch connector has an alignment pin that
4306 goes through a hole in the PC board when you have the cable
4312 Attach a battery to the TeleMetrum board if you're using one.
4317 Plug both the programmer and the TeleDongle into your computer's USB
4318 ports, and power up the programmer.
4323 Run AltosUI, and select 'Flash Image' from the File menu.
4328 Pick the programmer device from the list, identifying it as the
4334 Select the image you want put on the TeleDongle, which should have a
4335 name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
4336 in the default directory, if not you may have to poke around
4337 your system to find it.
4342 Make sure the configuration parameters are reasonable
4343 looking. If the serial number and/or RF configuration
4344 values aren't right, you'll need to change them. The TeleDongle
4345 serial number is on the “bottom” of the circuit board, and can
4346 usually be read through the translucent blue plastic case without
4347 needing to remove the board from the case.
4352 Hit the 'OK' button and the software should proceed to flash
4353 the TeleDongle with new firmware, showing a progress bar.
4358 Confirm that the TeleDongle board seems to have updated OK, which you
4359 can do by plugging in to it over USB and using a terminal program
4360 to connect to the board and issue the 'v' command to check
4361 the version, etc. Once you're happy, remove the programming cable
4362 and put the cover back on the TeleDongle.
4367 If something goes wrong, give it another try.
4372 Be careful removing the programming cable from the locking 8-pin
4373 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
4374 screwdriver or knife blade to gently pry the locking ears out
4375 slightly to extract the connector. We used a locking connector on
4376 TeleMetrum to help ensure that the cabling to companion boards
4377 used in a rocket don't ever come loose accidentally in flight.
4382 <title>Hardware Specifications</title>
4385 TeleMega Specifications
4390 Recording altimeter for model rocketry.
4395 Supports dual deployment and four auxiliary pyro channels
4396 (a total of 6 events).
4401 70cm 40mW ham-band transceiver for telemetry down-link.
4406 Barometric pressure sensor good to 100k feet MSL.
4411 1-axis high-g accelerometer for motor characterization, capable of
4417 9-axis IMU including integrated 3-axis accelerometer,
4418 3-axis gyroscope and 3-axis magnetometer.
4423 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
4428 On-board 8 Megabyte non-volatile memory for flight data storage.
4433 USB interface for battery charging, configuration, and data recovery.
4438 Fully integrated support for Li-Po rechargeable batteries.
4443 Can use either main system Li-Po or optional separate pyro battery
4449 3.25 x 1.25 inch board designed to fit inside 38mm air-frame coupler tube.
4456 TeleMetrum v2 Specifications
4461 Recording altimeter for model rocketry.
4466 Supports dual deployment (can fire 2 ejection charges).
4471 70cm, 40mW ham-band transceiver for telemetry down-link.
4476 Barometric pressure sensor good to 100k feet MSL.
4481 1-axis high-g accelerometer for motor characterization, capable of
4487 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
4492 On-board 8 Megabyte non-volatile memory for flight data storage.
4497 USB interface for battery charging, configuration, and data recovery.
4502 Fully integrated support for Li-Po rechargeable batteries.
4507 Uses Li-Po to fire e-matches, can be modified to support
4508 optional separate pyro battery if needed.
4513 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
4519 <title>TeleMetrum v1 Specifications</title>
4523 Recording altimeter for model rocketry.
4528 Supports dual deployment (can fire 2 ejection charges).
4533 70cm, 10mW ham-band transceiver for telemetry down-link.
4538 Barometric pressure sensor good to 45k feet MSL.
4543 1-axis high-g accelerometer for motor characterization, capable of
4544 +/- 50g using default part.
4549 On-board, integrated GPS receiver with 5Hz update rate capability.
4554 On-board 1 megabyte non-volatile memory for flight data storage.
4559 USB interface for battery charging, configuration, and data recovery.
4564 Fully integrated support for Li-Po rechargeable batteries.
4569 Uses Li-Po to fire e-matches, can be modified to support
4570 optional separate pyro battery if needed.
4575 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
4582 TeleMini v2.0 Specifications
4587 Recording altimeter for model rocketry.
4592 Supports dual deployment (can fire 2 ejection charges).
4597 70cm, 10mW ham-band transceiver for telemetry down-link.
4602 Barometric pressure sensor good to 100k feet MSL.
4607 On-board 1 megabyte non-volatile memory for flight data storage.
4612 USB interface for configuration, and data recovery.
4617 Support for Li-Po rechargeable batteries (using an
4618 external charger), or any 3.7-15V external battery.
4623 Uses Li-Po to fire e-matches, can be modified to support
4624 optional separate pyro battery if needed.
4629 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
4636 TeleMini v1.0 Specifications
4641 Recording altimeter for model rocketry.
4646 Supports dual deployment (can fire 2 ejection charges).
4651 70cm, 10mW ham-band transceiver for telemetry down-link.
4656 Barometric pressure sensor good to 45k feet MSL.
4661 On-board 5 kilobyte non-volatile memory for flight data storage.
4666 RF interface for configuration, and data recovery.
4671 Support for Li-Po rechargeable batteries, using an external charger.
4676 Uses Li-Po to fire e-matches, can be modified to support
4677 optional separate pyro battery if needed.
4682 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube.
4689 EasyMini Specifications
4694 Recording altimeter for model rocketry.
4699 Supports dual deployment (can fire 2 ejection charges).
4704 Barometric pressure sensor good to 100k feet MSL.
4709 On-board 1 megabyte non-volatile memory for flight data storage.
4714 USB interface for configuration, and data recovery.
4719 Support for Li-Po rechargeable batteries (using an
4720 external charger), or any 3.7-15V external battery.
4725 Uses Li-Po to fire e-matches, can be modified to support
4726 optional separate pyro battery if needed.
4731 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
4740 <emphasis>TeleMetrum seems to shut off when disconnected from the
4741 computer.</emphasis> <?linebreak?>
4742 Make sure the battery is adequately charged. Remember the
4743 unit will pull more power than the USB port can deliver before the
4744 GPS enters “locked” mode. The battery charges best when TeleMetrum
4748 <emphasis>It's impossible to stop the TeleDongle when it's in “p” mode, I have
4749 to unplug the USB cable? </emphasis><?linebreak?>
4750 Make sure you have tried to “escape out” of
4751 this mode. If this doesn't work the reboot procedure for the
4752 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
4753 outgoing buffer IF your “escape out” ('~~') does not work.
4754 At this point using either 'ao-view' (or possibly
4755 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
4759 <emphasis>The amber LED (on the TeleMetrum) lights up when both
4760 battery and USB are connected. Does this mean it's charging?
4761 </emphasis><?linebreak?>
4762 Yes, the yellow LED indicates the charging at the 'regular' rate.
4763 If the led is out but the unit is still plugged into a USB port,
4764 then the battery is being charged at a 'trickle' rate.
4767 <emphasis>There are no “dit-dah-dah-dit” sound or lights like the manual
4768 mentions?</emphasis><?linebreak?>
4769 That's the “pad” mode. Weak batteries might be the problem.
4770 It is also possible that the flight computer is horizontal and the
4772 is instead a “dit-dit” meaning 'idle'. For TeleMini, it's possible that
4773 it received a command packet which would have left it in “pad” mode.
4776 <emphasis>How do I save flight data?</emphasis><?linebreak?>
4777 Live telemetry is written to file(s) whenever AltosUI is connected
4778 to the TeleDongle. The file area defaults to ~/TeleMetrum
4779 but is easily changed using the menus in AltosUI. The files that
4780 are written end in '.telem'. The after-flight
4781 data-dumped files will end in .eeprom and represent continuous data
4782 unlike the .telem files that are subject to losses
4783 along the RF data path.
4784 See the above instructions on what and how to save the eeprom stored
4785 data after physically retrieving your altimeter. Make sure to save
4786 the on-board data after each flight; while the TeleMetrum can store
4787 multiple flights, you never know when you'll lose the altimeter...
4791 <title>Notes for Older Software</title>
4794 Before AltosUI was written, using Altus Metrum devices required
4795 some finesse with the Linux command line. There was a limited
4796 GUI tool, ao-view, which provided functionality similar to the
4797 Monitor Flight window in AltosUI, but everything else was a
4798 fairly 80's experience. This appendix includes documentation for
4799 using that software.
4803 Both TeleMetrum and TeleDongle can be directly communicated
4804 with using USB ports. The first thing you should try after getting
4805 both units plugged into to your computer's USB port(s) is to run
4806 'ao-list' from a terminal-window to see what port-device-name each
4807 device has been assigned by the operating system.
4808 You will need this information to access the devices via their
4809 respective on-board firmware and data using other command line
4810 programs in the AltOS software suite.
4813 TeleMini can be communicated with through a TeleDongle device
4814 over the radio link. When first booted, TeleMini listens for a
4815 TeleDongle device and if it receives a packet, it goes into
4816 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be
4817 launched. The easiest way to get it talking is to start the
4818 communication link on the TeleDongle and the power up the
4822 To access the device's firmware for configuration you need a terminal
4823 program such as you would use to talk to a modem. The software
4824 authors prefer using the program 'cu' which comes from the UUCP package
4825 on most Unix-like systems such as Linux. An example command line for
4826 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
4827 indicated from running the
4828 ao-list program. Another reasonable terminal program for Linux is
4829 'cutecom'. The default 'escape'
4830 character used by CU (i.e. the character you use to
4831 issue commands to cu itself instead of sending the command as input
4832 to the connected device) is a '~'. You will need this for use in
4833 only two different ways during normal operations. First is to exit
4834 the program by sending a '~.' which is called a 'escape-disconnect'
4835 and allows you to close-out from 'cu'. The
4836 second use will be outlined later.
4839 All of the Altus Metrum devices share the concept of a two level
4840 command set in their firmware.
4841 The first layer has several single letter commands. Once
4842 you are using 'cu' (or 'cutecom') sending (typing) a '?'
4843 returns a full list of these
4844 commands. The second level are configuration sub-commands accessed
4845 using the 'c' command, for
4846 instance typing 'c?' will give you this second level of commands
4847 (all of which require the
4848 letter 'c' to access). Please note that most configuration options
4849 are stored only in Flash memory; TeleDongle doesn't provide any storage
4850 for these options and so they'll all be lost when you unplug it.
4853 Try setting these configuration ('c' or second level menu) values. A good
4854 place to start is by setting your call sign. By default, the boards
4855 use 'N0CALL' which is cute, but not exactly legal!
4856 Spend a few minutes getting comfortable with the units, their
4857 firmware, and 'cu' (or possibly 'cutecom').
4858 For instance, try to send
4859 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
4860 Verify you can connect and disconnect from the units while in your
4861 terminal program by sending the escape-disconnect mentioned above.
4864 To set the radio frequency, use the 'c R' command to specify the
4865 radio transceiver configuration parameter. This parameter is computed
4866 using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
4867 the standard calibration reference frequency, 'S', (normally 434.550MHz):
4871 Round the result to the nearest integer value.
4872 As with all 'c' sub-commands, follow this with a 'c w' to write the
4873 change to the parameter block in the on-board flash on
4874 your altimeter board if you want the change to stay in place across reboots.
4877 To set the apogee delay, use the 'c d' command.
4878 As with all 'c' sub-commands, follow this with a 'c w' to write the
4879 change to the parameter block in the on-board DataFlash chip.
4882 To set the main deployment altitude, use the 'c m' 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 calibrate the radio frequency, connect the UHF antenna port to a
4888 frequency counter, set the board to 434.550MHz, and use the 'C'
4889 command to generate a CW carrier. Wait for the transmitter temperature
4890 to stabilize and the frequency to settle down.
4891 Then, divide 434.550 MHz by the
4892 measured frequency and multiply by the current radio cal value show
4893 in the 'c s' command. For an unprogrammed board, the default value
4894 is 1186611 for cc1111 based products and 7119667 for cc1120
4895 based products. Take the resulting integer and program it using the 'c f'
4896 command. Testing with the 'C' command again should show a carrier
4897 within a few tens of Hertz of the intended frequency.
4898 As with all 'c' sub-commands, follow this with a 'c w' to write the
4899 change to the configuration memory.
4902 Note that the 'reboot' command, which is very useful on the altimeters,
4903 will likely just cause problems with the dongle. The *correct* way
4904 to reset the dongle is just to unplug and re-plug it.
4907 A fun thing to do at the launch site and something you can do while
4908 learning how to use these units is to play with the radio link access
4909 between an altimeter and the TeleDongle. Be aware that you *must* create
4910 some physical separation between the devices, otherwise the link will
4911 not function due to signal overload in the receivers in each device.
4914 Now might be a good time to take a break and read the rest of this
4915 manual, particularly about the two “modes” that the altimeters
4916 can be placed in. TeleMetrum uses the position of the device when booting
4917 up will determine whether the unit is in “pad” or “idle” mode. TeleMini
4918 enters “idle” mode when it receives a command packet within the first 5 seconds
4919 of being powered up, otherwise it enters “pad” mode.
4922 You can access an altimeter in idle mode from the TeleDongle's USB
4923 connection using the radio link
4924 by issuing a 'p' command to the TeleDongle. Practice connecting and
4925 disconnecting ('~~' while using 'cu') from the altimeter. If
4926 you cannot escape out of the “p” command, (by using a '~~' when in
4927 CU) then it is likely that your kernel has issues. Try a newer version.
4930 Using this radio link allows you to configure the altimeter, test
4931 fire e-matches and igniters from the flight line, check pyro-match
4932 continuity and so forth. You can leave the unit turned on while it
4933 is in 'idle mode' and then place the
4934 rocket vertically on the launch pad, walk away and then issue a
4935 reboot command. The altimeter will reboot and start sending data
4936 having changed to the “pad” mode. If the TeleDongle is not receiving
4937 this data, you can disconnect 'cu' from the TeleDongle using the
4938 procedures mentioned above and THEN connect to the TeleDongle from
4939 inside 'ao-view'. If this doesn't work, disconnect from the
4940 TeleDongle, unplug it, and try again after plugging it back in.
4943 In order to reduce the chance of accidental firing of pyrotechnic
4944 charges, the command to fire a charge is intentionally somewhat
4945 difficult to type, and the built-in help is slightly cryptic to
4946 prevent accidental echoing of characters from the help text back at
4947 the board from firing a charge. The command to fire the apogee
4948 drogue charge is 'i DoIt drogue' and the command to fire the main
4949 charge is 'i DoIt main'.
4952 On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
4953 and 'ao-view' will both auditorily announce and visually indicate
4955 Now you can launch knowing that you have a good data path and
4956 good satellite lock for flight data and recovery. Remember
4957 you MUST tell ao-view to connect to the TeleDongle explicitly in
4958 order for ao-view to be able to receive data.
4961 The altimeters provide RDF (radio direction finding) tones on
4962 the pad, during descent and after landing. These can be used to
4963 locate the rocket using a directional antenna; the signal
4964 strength providing an indication of the direction from receiver to rocket.
4967 TeleMetrum also provides GPS tracking data, which can further simplify
4968 locating the rocket once it has landed. (The last good GPS data
4969 received before touch-down will be on the data screen of 'ao-view'.)
4972 Once you have recovered the rocket you can download the eeprom
4973 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
4974 either a USB cable or over the radio link using TeleDongle.
4975 And by following the man page for 'ao-postflight' you can create
4976 various data output reports, graphs, and even KML data to see the
4977 flight trajectory in Google-earth. (Moving the viewing angle making
4978 sure to connect the yellow lines while in Google-earth is the proper
4982 As for ao-view.... some things are in the menu but don't do anything
4983 very useful. The developers have stopped working on ao-view to focus
4984 on a new, cross-platform ground station program. So ao-view may or
4985 may not be updated in the future. Mostly you just use
4986 the Log and Device menus. It has a wonderful display of the incoming
4987 flight data and I am sure you will enjoy what it has to say to you
4988 once you enable the voice output!
4992 <title>Drill Templates</title>
4994 These images, when printed, provide precise templates for the
4995 mounting holes in Altus Metrum flight computers
4998 <title>TeleMega template</title>
5000 TeleMega has overall dimensions of 1.250 x 3.250 inches, and
5001 the mounting holes are sized for use with 4-40 or M3 screws.
5004 <mediaobject id="TeleMegaTemplate">
5006 <imagedata format="SVG" fileref="telemega-outline.svg"/>
5012 <title>TeleMetrum template</title>
5014 TeleMetrum has overall dimensions of 1.000 x 2.750 inches, and the
5015 mounting holes are sized for use with 4-40 or M3 screws.
5018 <mediaobject id="TeleMetrumTemplate">
5020 <imagedata format="SVG" fileref="telemetrum.svg"/>
5026 <title>TeleMini v2/EasyMini template</title>
5028 TeleMini v2 and EasyMini have overall dimensions of 0.800 x 1.500 inches, and the
5029 mounting holes are sized for use with 4-40 or M3 screws.
5032 <mediaobject id="MiniTemplate">
5034 <imagedata format="SVG" fileref="easymini-outline.svg"/>
5040 <title>TeleMini v1 template</title>
5042 TeleMini has overall dimensions of 0.500 x 1.500 inches, and the
5043 mounting holes are sized for use with 2-56 or M2 screws.
5046 <mediaobject id="TeleMiniTemplate">
5048 <imagedata format="SVG" fileref="telemini.svg"/>
5055 <title>Calibration</title>
5057 There are only two calibrations required for TeleMetrum and
5058 TeleMega, and only one for TeleDongle, TeleMini and EasyMini.
5059 All boards are shipped from the factory pre-calibrated, but
5060 the procedures are documented here in case they are ever
5061 needed. Re-calibration is not supported by AltosUI, you must
5062 connect to the board with a serial terminal program and
5063 interact directly with the on-board command interpreter to
5067 <title>Radio Frequency</title>
5069 The radio frequency is synthesized from a clock based on the
5070 crystal on the board. The actual frequency of this oscillator
5071 must be measured to generate a calibration constant. While our
5073 bandwidth is wide enough to allow boards to communicate even when
5074 their oscillators are not on exactly the same frequency, performance
5075 is best when they are closely matched.
5076 Radio frequency calibration requires a calibrated frequency counter.
5077 Fortunately, once set, the variation in frequency due to aging and
5078 temperature changes is small enough that re-calibration by customers
5079 should generally not be required.
5082 To calibrate the radio frequency, connect the UHF antenna
5083 port to a frequency counter, set the board to 434.550MHz,
5084 and use the 'C' command in the on-board command interpreter
5085 to generate a CW carrier. For USB-enabled boards, this is
5086 best done over USB. For TeleMini v1, note that the only way
5087 to escape the 'C' command is via power cycle since the board
5088 will no longer be listening for commands once it starts
5089 generating a CW carrier.
5092 Wait for the transmitter temperature to stabilize and the frequency
5093 to settle down. Then, divide 434.550 MHz by the
5094 measured frequency and multiply by the current radio cal value show
5095 in the 'c s' command. For an unprogrammed board, the default value
5096 is 1186611. Take the resulting integer and program it using the 'c f'
5097 command. Testing with the 'C' command again should show a carrier
5098 within a few tens of Hertz of the intended frequency.
5099 As with all 'c' sub-commands, follow this with a 'c w' to write the
5100 change to the parameter block in the on-board storage chip.
5103 Note that any time you re-do the radio frequency calibration, the
5104 radio frequency is reset to the default 434.550 Mhz. If you want
5105 to use another frequency, you will have to set that again after
5106 calibration is completed.
5110 <title>TeleMetrum and TeleMega Accelerometers</title>
5112 While barometric sensors are factory-calibrated,
5113 accelerometers are not, and so each must be calibrated once
5114 installed in a flight computer. Explicitly calibrating the
5115 accelerometers also allows us to load any compatible device.
5116 We perform a two-point calibration using gravity.
5119 To calibrate the acceleration sensor, use the 'c a 0' command. You
5120 will be prompted to orient the board vertically with the UHF antenna
5121 up and press a key, then to orient the board vertically with the
5122 UHF antenna down and press a key. Note that the accuracy of this
5123 calibration depends primarily on how perfectly vertical and still
5124 the board is held during the cal process. As with all 'c'
5125 sub-commands, follow this with a 'c w' to write the
5126 change to the parameter block in the on-board DataFlash chip.
5129 The +1g and -1g calibration points are included in each telemetry
5130 frame and are part of the header stored in onboard flash to be
5131 downloaded after flight. We always store and return raw ADC
5132 samples for each sensor... so nothing is permanently “lost” or
5133 “damaged” if the calibration is poor.
5136 In the unlikely event an accel cal goes badly, it is possible
5137 that TeleMetrum or TeleMega may always come up in 'pad mode'
5138 and as such not be listening to either the USB or radio link.
5139 If that happens, there is a special hook in the firmware to
5140 force the board back in to 'idle mode' so you can re-do the
5141 cal. To use this hook, you just need to ground the SPI clock
5142 pin at power-on. This pin is available as pin 2 on the 8-pin
5143 companion connector, and pin 1 is ground. So either
5144 carefully install a fine-gauge wire jumper between the two
5145 pins closest to the index hole end of the 8-pin connector, or
5146 plug in the programming cable to the 8-pin connector and use
5147 a small screwdriver or similar to short the two pins closest
5148 to the index post on the 4-pin end of the programming cable,
5149 and power up the board. It should come up in 'idle mode'
5150 (two beeps), allowing a re-cal.
5155 <title>Release Notes</title>
5157 <title>Version 1.3.2</title>
5159 xmlns:xi="http://www.w3.org/2001/XInclude"
5160 href="release-notes-1.3.2.xsl"
5161 xpointer="xpointer(/article/*)"/>
5164 <title>Version 1.3.1</title>
5166 xmlns:xi="http://www.w3.org/2001/XInclude"
5167 href="release-notes-1.3.1.xsl"
5168 xpointer="xpointer(/article/*)"/>
5171 <title>Version 1.3</title>
5173 xmlns:xi="http://www.w3.org/2001/XInclude"
5174 href="release-notes-1.3.xsl"
5175 xpointer="xpointer(/article/*)"/>
5178 <title>Version 1.2.1</title>
5180 xmlns:xi="http://www.w3.org/2001/XInclude"
5181 href="release-notes-1.2.1.xsl"
5182 xpointer="xpointer(/article/*)"/>
5185 <title>Version 1.2</title>
5187 xmlns:xi="http://www.w3.org/2001/XInclude"
5188 href="release-notes-1.2.xsl"
5189 xpointer="xpointer(/article/*)"/>
5192 <title>Version 1.1.1</title>
5194 xmlns:xi="http://www.w3.org/2001/XInclude"
5195 href="release-notes-1.1.1.xsl"
5196 xpointer="xpointer(/article/*)"/>
5199 <title>Version 1.1</title>
5201 xmlns:xi="http://www.w3.org/2001/XInclude"
5202 href="release-notes-1.1.xsl"
5203 xpointer="xpointer(/article/*)"/>
5206 <title>Version 1.0.1</title>
5208 xmlns:xi="http://www.w3.org/2001/XInclude"
5209 href="release-notes-1.0.1.xsl"
5210 xpointer="xpointer(/article/*)"/>
5213 <title>Version 0.9.2</title>
5215 xmlns:xi="http://www.w3.org/2001/XInclude"
5216 href="release-notes-0.9.2.xsl"
5217 xpointer="xpointer(/article/*)"/>
5220 <title>Version 0.9</title>
5222 xmlns:xi="http://www.w3.org/2001/XInclude"
5223 href="release-notes-0.9.xsl"
5224 xpointer="xpointer(/article/*)"/>
5227 <title>Version 0.8</title>
5229 xmlns:xi="http://www.w3.org/2001/XInclude"
5230 href="release-notes-0.8.xsl"
5231 xpointer="xpointer(/article/*)"/>
5234 <title>Version 0.7.1</title>
5236 xmlns:xi="http://www.w3.org/2001/XInclude"
5237 href="release-notes-0.7.1.xsl"
5238 xpointer="xpointer(/article/*)"/>
5243 <!-- LocalWords: Altusmetrum
projects / fw / altos / blob