1 <?xml version="1.0" encoding="utf-8"?>
2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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5 <title>The Altus Metrum System</title>
6 <subtitle>An Owner's Manual for Altus Metrum Rocketry Electronics</subtitle>
9 <firstname>Bdale</firstname>
10 <surname>Garbee</surname>
13 <firstname>Keith</firstname>
14 <surname>Packard</surname>
17 <firstname>Bob</firstname>
18 <surname>Finch</surname>
21 <firstname>Anthony</firstname>
22 <surname>Towns</surname>
26 <holder>Bdale Garbee and Keith Packard</holder>
30 <imagedata fileref="../themes/background.png" width="6.0in"/>
35 This document is released under the terms of the
36 <ulink url="http://creativecommons.org/licenses/by-sa/3.0/">
37 Creative Commons ShareAlike 3.0
44 <revnumber>1.5</revnumber>
45 <date>6 September 2014</date>
47 Major release adding EasyMega support.
51 <revnumber>1.4.1</revnumber>
52 <date>20 June 2014</date>
54 Minor release fixing some installation bugs.
58 <revnumber>1.4</revnumber>
59 <date>15 June 2014</date>
61 Major release adding TeleGPS support.
65 <revnumber>1.3.2</revnumber>
66 <date>24 January 2014</date>
68 Bug fixes for TeleMega and AltosUI.
72 <revnumber>1.3.1</revnumber>
73 <date>21 January 2014</date>
75 Bug fixes for TeleMega and TeleMetrum v2.0 along with a few
76 small UI improvements.
80 <revnumber>1.3</revnumber>
81 <date>12 November 2013</date>
83 Updated for software version 1.3. Version 1.3 adds support
84 for TeleMega, TeleMetrum v2.0, TeleMini v2.0 and EasyMini
85 and fixes bugs in AltosUI and the AltOS firmware.
89 <revnumber>1.2.1</revnumber>
90 <date>21 May 2013</date>
92 Updated for software version 1.2. Version 1.2 adds support
93 for TeleBT and AltosDroid. It also adds a few minor features
94 and fixes bugs in AltosUI and the AltOS firmware.
98 <revnumber>1.2</revnumber>
99 <date>18 April 2013</date>
101 Updated for software version 1.2. Version 1.2 adds support
102 for MicroPeak and the MicroPeak USB interface.
106 <revnumber>1.1.1</revnumber>
107 <date>16 September 2012</date>
109 Updated for software version 1.1.1 Version 1.1.1 fixes a few
110 bugs found in version 1.1.
114 <revnumber>1.1</revnumber>
115 <date>13 September 2012</date>
117 Updated for software version 1.1. Version 1.1 has new
118 features but is otherwise compatible with version 1.0.
122 <revnumber>1.0</revnumber>
123 <date>24 August 2011</date>
125 Updated for software version 1.0. Note that 1.0 represents a
126 telemetry format change, meaning both ends of a link
127 (TeleMetrum/TeleMini and TeleDongle) must be updated or
128 communications will fail.
132 <revnumber>0.9</revnumber>
133 <date>18 January 2011</date>
135 Updated for software version 0.9. Note that 0.9 represents a
136 telemetry format change, meaning both ends of a link (TeleMetrum and
137 TeleDongle) must be updated or communications will fail.
141 <revnumber>0.8</revnumber>
142 <date>24 November 2010</date>
143 <revremark>Updated for software version 0.8 </revremark>
148 <title>Acknowledgments</title>
150 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing “The
151 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
152 Kit” which formed the basis of the original Getting Started chapter
153 in this manual. Bob was one of our first customers for a production
154 TeleMetrum, and his continued enthusiasm and contributions
155 are immensely gratifying and highly appreciated!
158 And thanks to Anthony (AJ) Towns for major contributions including
159 the AltosUI graphing and site map code and associated documentation.
160 Free software means that our customers and friends can become our
161 collaborators, and we certainly appreciate this level of
165 Have fun using these products, and we hope to meet all of you
166 out on the rocket flight line somewhere.
169 NAR #87103, TRA #12201
171 Keith Packard, KD7SQG
172 NAR #88757, TRA #12200
177 <title>Introduction and Overview</title>
179 Welcome to the Altus Metrum community! Our circuits and software reflect
180 our passion for both hobby rocketry and Free Software. We hope their
181 capabilities and performance will delight you in every way, but by
182 releasing all of our hardware and software designs under open licenses,
183 we also hope to empower you to take as active a role in our collective
187 The first device created for our community was TeleMetrum, a dual
188 deploy altimeter with fully integrated GPS and radio telemetry
189 as standard features, and a “companion interface” that will
190 support optional capabilities in the future. The latest version
191 of TeleMetrum, v2.0, has all of the same features but with
192 improved sensors and radio to offer increased performance.
195 Our second device was TeleMini, a dual deploy altimeter with
196 radio telemetry and radio direction finding. The first version
197 of this device was only 13mm by 38mm (½ inch by 1½ inches) and
198 could fit easily in an 18mm air-frame. The latest version, v2.0,
199 includes a beeper, USB data download and extended on-board
200 flight logging, along with an improved barometric sensor.
203 TeleMega is our most sophisticated device, including six pyro
204 channels (four of which are fully programmable), integrated GPS,
205 integrated gyroscopes for staging/air-start inhibit and high
206 performance telemetry.
209 EasyMini is a dual-deploy altimeter with logging and built-in
213 EasyMega is essentially a TeleMega board with the GPS receiver
214 and telemetry transmitter removed. It offers the same 6 pyro
215 channels and integrated gyroscopes for staging/air-start inhibit.
218 TeleDongle was our first ground station, providing a USB to RF
219 interfaces for communicating with the altimeters. Combined with
220 your choice of antenna and notebook computer, TeleDongle and our
221 associated user interface software form a complete ground
222 station capable of logging and displaying in-flight telemetry,
223 aiding rocket recovery, then processing and archiving flight
224 data for analysis and review.
227 For a slightly more portable ground station experience that also
228 provides direct rocket recovery support, TeleBT offers flight
229 monitoring and data logging using a Bluetooth™ connection between
230 the receiver and an Android device that has the AltosDroid
231 application installed from the Google Play store.
234 More products will be added to the Altus Metrum family over time, and
235 we currently envision that this will be a single, comprehensive manual
236 for the entire product family.
240 <title>Getting Started</title>
242 The first thing to do after you check the inventory of parts in your
243 “starter kit” is to charge the battery.
246 For TeleMetrum, TeleMega and EasyMega, the battery can be charged by plugging it into the
247 corresponding socket of the device and then using the USB
248 cable to plug the flight computer into your computer's USB socket. The
249 on-board circuitry will charge the battery whenever it is plugged
250 in, because the on-off switch does NOT control the
254 On TeleMetrum v1 boards, when the GPS chip is initially
255 searching for satellites, TeleMetrum will consume more current
256 than it pulls from the USB port, so the battery must be
257 attached in order to get satellite lock. Once GPS is locked,
258 the current consumption goes back down enough to enable charging
259 while running. So it's a good idea to fully charge the battery
260 as your first item of business so there is no issue getting and
261 maintaining satellite lock. The yellow charge indicator led
262 will go out when the battery is nearly full and the charger goes
263 to trickle charge. It can take several hours to fully recharge a
264 deeply discharged battery.
267 TeleMetrum v2.0, TeleMega and EasyMega use a higher power battery charger,
268 allowing them to charge the battery while running the board at
269 maximum power. When the battery is charging, or when the board
270 is consuming a lot of power, the red LED will be lit. When the
271 battery is fully charged, the green LED will be lit. When the
272 battery is damaged or missing, both LEDs will be lit, which
276 The Lithium Polymer TeleMini and EasyMini battery can be charged by
277 disconnecting it from the board and plugging it into a
278 standalone battery charger such as the LipoCharger product
279 included in TeleMini Starter Kits, and connecting that via a USB
280 cable to a laptop or other USB power source.
283 You can also choose to use another battery with TeleMini v2.0
284 and EasyMini, anything supplying between 4 and 12 volts should
285 work fine (like a standard 9V battery), but if you are planning
286 to fire pyro charges, ground testing is required to verify that
287 the battery supplies enough current to fire your chosen e-matches.
290 The other active device in the starter kit is the TeleDongle USB to
291 RF interface. If you plug it in to your Mac or Linux computer it should
292 “just work”, showing up as a serial port device. Windows systems need
293 driver information that is part of the AltOS download to know that the
294 existing USB modem driver will work. We therefore recommend installing
295 our software before plugging in TeleDongle if you are using a Windows
296 computer. If you are using an older version of Linux and are having
297 problems, try moving to a fresher kernel (2.6.33 or newer).
300 Next you should obtain and install the AltOS software. The AltOS
301 distribution includes the AltosUI ground station program, current
303 images for all of the hardware, and a number of standalone
304 utilities that are rarely needed. Pre-built binary packages are
305 available for Linux, Microsoft Windows, and recent MacOSX
306 versions. Full source code and build instructions are also
307 available. The latest version may always be downloaded from
308 <ulink url="http://altusmetrum.org/AltOS"/>.
311 If you're using a TeleBT instead of the TeleDongle, you'll want to
312 install the AltosDroid application from the Google Play store on an
313 Android device. You don't need a data plan to use AltosDroid, but
314 without network access, the Map view will be less useful as it
315 won't contain any map data. You can also use TeleBT connected
316 over USB with your laptop computer; it acts exactly like a
317 TeleDongle. Anywhere this manual talks about TeleDongle, you can
318 also read that as 'and TeleBT when connected via USB'.
322 <title>Handling Precautions</title>
324 All Altus Metrum products are sophisticated electronic devices.
325 When handled gently and properly installed in an air-frame, they
326 will deliver impressive results. However, as with all electronic
327 devices, there are some precautions you must take.
330 The Lithium Polymer rechargeable batteries have an
331 extraordinary power density. This is great because we can fly with
332 much less battery mass than if we used alkaline batteries or previous
333 generation rechargeable batteries... but if they are punctured
334 or their leads are allowed to short, they can and will release their
336 Thus we recommend that you take some care when handling our batteries
337 and consider giving them some extra protection in your air-frame. We
338 often wrap them in suitable scraps of closed-cell packing foam before
339 strapping them down, for example.
342 The barometric sensors used on all of our flight computers are
343 sensitive to sunlight. In normal mounting situations, the baro sensor
344 and all of the other surface mount components
345 are “down” towards whatever the underlying mounting surface is, so
346 this is not normally a problem. Please consider this when designing an
347 installation in an air-frame with a see-through plastic payload bay. It
348 is particularly important to
349 consider this with TeleMini v1.0, both because the baro sensor is on the
350 “top” of the board, and because many model rockets with payload bays
351 use clear plastic for the payload bay! Replacing these with an opaque
352 cardboard tube, painting them, or wrapping them with a layer of masking
353 tape are all reasonable approaches to keep the sensor out of direct
357 The barometric sensor sampling port must be able to “breathe”,
358 both by not being covered by foam or tape or other materials that might
359 directly block the hole on the top of the sensor, and also by having a
360 suitable static vent to outside air.
363 As with all other rocketry electronics, Altus Metrum altimeters must
364 be protected from exposure to corrosive motor exhaust and ejection
369 <title>Altus Metrum Hardware</title>
371 <title>General Usage Instructions</title>
373 Here are general instructions for hooking up an Altus Metrum
374 flight computer. Instructions specific to each model will be
375 found in the section devoted to that model below.
378 To prevent electrical interference from affecting the
379 operation of the flight computer, it's important to always
380 twist pairs of wires connected to the board. Twist the switch
381 leads, the pyro leads and the battery leads. This reduces
382 interference through a mechanism called common mode rejection.
385 <title>Hooking Up Lithium Polymer Batteries</title>
387 All Altus Metrum flight computers have a two pin JST PH
388 series connector to connect up a single-cell Lithium Polymer
389 cell (3.7V nominal). You can purchase matching batteries
390 from the Altus Metrum store, or other vendors, or you can
391 make your own. Pin 1 of the connector is positive, pin 2 is
392 negative. Spark Fun sells a cable with the connector
393 attached, which they call a <ulink
394 url="https://www.sparkfun.com/products/9914">JST Jumper 2
395 Wire Assembly</ulink>.
398 Many RC vendors also sell lithium polymer batteries with
399 this same connector. All that we have found use the opposite
400 polarity, and if you use them that way, you will damage or
401 destroy the flight computer.
405 <title>Hooking Up Pyro Charges</title>
407 Altus Metrum flight computers always have two screws for
408 each pyro charge. This means you shouldn't need to put two
409 wires into a screw terminal or connect leads from pyro
410 charges together externally.
413 On the flight computer, one lead from each charge is hooked
414 to the positive battery terminal through the power switch.
415 The other lead is connected through the pyro circuit, which
416 is connected to the negative battery terminal when the pyro
421 <title>Hooking Up a Power Switch</title>
423 Altus Metrum flight computers need an external power switch
424 to turn them on. This disconnects both the computer and the
425 pyro charges from the battery, preventing the charges from
426 firing when in the Off position. The switch is in-line with
427 the positive battery terminal.
430 <title>Using an External Active Switch Circuit</title>
432 You can use an active switch circuit, such as the
433 Featherweight Magnetic Switch, with any Altus Metrum
434 flight computer. These require three connections, one to
435 the battery, one to the positive power input on the flight
436 computer and one to ground. Find instructions on how to
437 hook these up for each flight computer below. The follow
438 the instructions that come with your active switch to
444 <title>Using a Separate Pyro Battery</title>
446 As mentioned above in the section on hooking up pyro
447 charges, one lead for each of the pyro charges is connected
448 through the power switch directly to the positive battery
449 terminal. The other lead is connected to the pyro circuit,
450 which connects it to the negative battery terminal when the
451 pyro circuit is fired. The pyro circuit on all of the flight
452 computers is designed to handle up to 16V.
455 To use a separate pyro battery, connect the negative pyro
456 battery terminal to the flight computer ground terminal,
457 the positive battery terminal to the igniter and the other
458 igniter lead to the negative pyro terminal on the flight
459 computer. When the pyro channel fires, it will complete the
460 circuit between the negative pyro terminal and the ground
461 terminal, firing the igniter. Specific instructions on how
462 to hook this up will be found in each section below.
466 <title>Using a Different Kind of Battery</title>
468 EasyMini and TeleMini v2 are designed to use either a
469 lithium polymer battery or any other battery producing
470 between 4 and 12 volts, such as a rectangular 9V
471 battery. TeleMega, EasyMega and TeleMetrum are not designed for this,
472 and must only be powered by a lithium polymer battery. Find
473 instructions on how to use other batteries in the EasyMini
474 and TeleMini sections below.
479 <title>Specifications</title>
481 Here's the full set of Altus Metrum products, both in
482 production and retired.
485 <title>Altus Metrum Electronics</title>
486 <?dbfo keep-together="always"?>
487 <tgroup cols='8' align='center' colsep='1' rowsep='1'>
488 <colspec align='center' colwidth='*' colname='Device'/>
489 <colspec align='center' colwidth='*' colname='Barometer'/>
490 <colspec align='center' colwidth='*' colname='Z-axis accelerometer'/>
491 <colspec align='center' colwidth='*' colname='GPS'/>
492 <colspec align='center' colwidth='*' colname='3D sensors'/>
493 <colspec align='center' colwidth='*' colname='Storage'/>
494 <colspec align='center' colwidth='*' colname='RF'/>
495 <colspec align='center' colwidth='*' colname='Battery'/>
498 <entry align='center'>Device</entry>
499 <entry align='center'>Barometer</entry>
500 <entry align='center'>Z-axis accelerometer</entry>
501 <entry align='center'>GPS</entry>
502 <entry align='center'>3D sensors</entry>
503 <entry align='center'>Storage</entry>
504 <entry align='center'>RF Output</entry>
505 <entry align='center'>Battery</entry>
510 <entry>TeleMetrum v1.0</entry>
511 <entry><para>MP3H6115 10km (33k')</para></entry>
512 <entry><para>MMA2202 50g</para></entry>
513 <entry>SkyTraq</entry>
520 <entry>TeleMetrum v1.1</entry>
521 <entry><para>MP3H6115 10km (33k')</para></entry>
522 <entry><para>MMA2202 50g</para></entry>
523 <entry>SkyTraq</entry>
530 <entry>TeleMetrum v1.2</entry>
531 <entry><para>MP3H6115 10km (33k')</para></entry>
532 <entry><para>ADXL78 70g</para></entry>
533 <entry>SkyTraq</entry>
540 <entry>TeleMetrum v2.0</entry>
541 <entry><para>MS5607 30km (100k')</para></entry>
542 <entry><para>MMA6555 102g</para></entry>
543 <entry>uBlox Max-7Q</entry>
550 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
551 <entry><para>MP3H6115 10km (33k')</para></entry>
560 <entry>TeleMini <?linebreak?>v2.0</entry>
561 <entry><para>MS5607 30km (100k')</para></entry>
567 <entry>3.7-12V</entry>
570 <entry>EasyMini <?linebreak?>v1.0</entry>
571 <entry><para>MS5607 30km (100k')</para></entry>
577 <entry>3.7-12V</entry>
580 <entry>TeleMega <?linebreak?>v1.0</entry>
581 <entry><para>MS5607 30km (100k')</para></entry>
582 <entry><para>MMA6555 102g</para></entry>
583 <entry>uBlox Max-7Q</entry>
584 <entry><para>MPU6000 HMC5883</para></entry>
590 <entry>EasyMega <?linebreak?>v1.0</entry>
591 <entry><para>MS5607 30km (100k')</para></entry>
592 <entry><para>MMA6555 102g</para></entry>
594 <entry><para>MPU6000 HMC5883</para></entry>
603 <title>Altus Metrum Boards</title>
604 <?dbfo keep-together="always"?>
605 <tgroup cols='6' align='center' colsep='1' rowsep='1'>
606 <colspec align='center' colwidth='*' colname='Device'/>
607 <colspec align='center' colwidth='*' colname='Connectors'/>
608 <colspec align='center' colwidth='*' colname='Screw Terminals'/>
609 <colspec align='center' colwidth='*' colname='Width'/>
610 <colspec align='center' colwidth='*' colname='Length'/>
611 <colspec align='center' colwidth='*' colname='Tube Size'/>
614 <entry align='center'>Device</entry>
615 <entry align='center'>Connectors</entry>
616 <entry align='center'>Screw Terminals</entry>
617 <entry align='center'>Width</entry>
618 <entry align='center'>Length</entry>
619 <entry align='center'>Tube Size</entry>
624 <entry>TeleMetrum</entry>
628 Companion<?linebreak?>
632 <entry><para>Apogee pyro <?linebreak?>Main pyro <?linebreak?>Switch</para></entry>
633 <entry>1 inch (2.54cm)</entry>
634 <entry>2 ¾ inch (6.99cm)</entry>
635 <entry>29mm coupler</entry>
638 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
645 Apogee pyro <?linebreak?>
648 <entry>½ inch (1.27cm)</entry>
649 <entry>1½ inch (3.81cm)</entry>
650 <entry>18mm coupler</entry>
653 <entry>TeleMini <?linebreak?>v2.0</entry>
661 Apogee pyro <?linebreak?>
662 Main pyro <?linebreak?>
663 Battery <?linebreak?>
666 <entry>0.8 inch (2.03cm)</entry>
667 <entry>1½ inch (3.81cm)</entry>
668 <entry>24mm coupler</entry>
671 <entry>EasyMini</entry>
678 Apogee pyro <?linebreak?>
679 Main pyro <?linebreak?>
680 Battery <?linebreak?>
683 <entry>0.8 inch (2.03cm)</entry>
684 <entry>1½ inch (3.81cm)</entry>
685 <entry>24mm coupler</entry>
688 <entry>TeleMega</entry>
692 Companion<?linebreak?>
697 Apogee pyro <?linebreak?>
698 Main pyro<?linebreak?>
699 Pyro A-D<?linebreak?>
703 <entry>1¼ inch (3.18cm)</entry>
704 <entry>3¼ inch (8.26cm)</entry>
705 <entry>38mm coupler</entry>
708 <entry>EasyMega</entry>
711 Companion<?linebreak?>
716 Apogee pyro <?linebreak?>
717 Main pyro<?linebreak?>
718 Pyro A-D<?linebreak?>
722 <entry>1¼ inch (3.18cm)</entry>
723 <entry>2¼ inch (5.62cm)</entry>
724 <entry>38mm coupler</entry>
731 <title>TeleMetrum</title>
735 <imagedata fileref="telemetrum-v1.1-thside.jpg" width="5.5in" scalefit="1"/>
740 TeleMetrum is a 1 inch by 2¾ inch circuit board. It was designed to
741 fit inside coupler for 29mm air-frame tubing, but using it in a tube that
742 small in diameter may require some creativity in mounting and wiring
743 to succeed! The presence of an accelerometer means TeleMetrum should
744 be aligned along the flight axis of the airframe, and by default the ¼
745 wave UHF wire antenna should be on the nose-cone end of the board. The
746 antenna wire is about 7 inches long, and wiring for a power switch and
747 the e-matches for apogee and main ejection charges depart from the
748 fin can end of the board, meaning an ideal “simple” avionics
749 bay for TeleMetrum should have at least 10 inches of interior length.
752 <title>TeleMetrum Screw Terminals</title>
754 TeleMetrum has six screw terminals on the end of the board
755 opposite the telemetry antenna. Two are for the power
756 switch, and two each for the apogee and main igniter
757 circuits. Using the picture above and starting from the top,
758 the terminals are as follows:
761 <title>TeleMetrum Screw Terminals</title>
762 <?dbfo keep-together="always"?>
763 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
764 <colspec align='center' colwidth='*' colname='Pin #'/>
765 <colspec align='center' colwidth='2*' colname='Pin Name'/>
766 <colspec align='left' colwidth='5*' colname='Description'/>
769 <entry align='center'>Terminal #</entry>
770 <entry align='center'>Terminal Name</entry>
771 <entry align='center'>Description</entry>
777 <entry>Switch Output</entry>
778 <entry>Switch connection to flight computer</entry>
782 <entry>Switch Input</entry>
783 <entry>Switch connection to positive battery terminal</entry>
787 <entry>Main +</entry>
788 <entry>Main pyro channel common connection to battery +</entry>
792 <entry>Main -</entry>
793 <entry>Main pyro channel connection to pyro circuit</entry>
797 <entry>Apogee +</entry>
798 <entry>Apogee pyro channel common connection to battery +</entry>
802 <entry>Apogee -</entry>
803 <entry>Apogee pyro channel connection to pyro circuit</entry>
810 <title>Using a Separate Pyro Battery with TeleMetrum</title>
812 As described above, using an external pyro battery involves
813 connecting the negative battery terminal to the flight
814 computer ground, connecting the positive battery terminal to
815 one of the igniter leads and connecting the other igniter
816 lead to the per-channel pyro circuit connection.
819 To connect the negative battery terminal to the TeleMetrum
820 ground, insert a small piece of wire, 24 to 28 gauge
821 stranded, into the GND hole just above the screw terminal
822 strip and solder it in place.
825 Connecting the positive battery terminal to the pyro
826 charges must be done separate from TeleMetrum, by soldering
827 them together or using some other connector.
830 The other lead from each pyro charge is then inserted into
831 the appropriate per-pyro channel screw terminal (terminal 4 for the
832 Main charge, terminal 6 for the Apogee charge).
836 <title>Using an Active Switch with TeleMetrum</title>
838 As explained above, an external active switch requires three
839 connections, one to the positive battery terminal, one to
840 the flight computer positive input and one to ground.
843 The positive battery terminal is available on screw terminal
844 2, the positive flight computer input is on terminal 1. To
845 hook a lead to ground, solder a piece of wire, 24 to 28
846 gauge stranded, to the GND hole just above terminal 1.
851 <title>TeleMini v1.0</title>
855 <imagedata fileref="telemini-v1-top.jpg" width="5.5in" scalefit="1"/>
860 TeleMini v1.0 is ½ inches by 1½ inches. It was
861 designed to fit inside an 18mm air-frame tube, but using it in
862 a tube that small in diameter may require some creativity in
863 mounting and wiring to succeed! Since there is no
864 accelerometer, TeleMini can be mounted in any convenient
865 orientation. The default ¼ wave UHF wire antenna attached to
866 the center of one end of the board is about 7 inches long. Two
867 wires for the power switch are connected to holes in the
868 middle of the board. Screw terminals for the e-matches for
869 apogee and main ejection charges depart from the other end of
870 the board, meaning an ideal “simple” avionics bay for TeleMini
871 should have at least 9 inches of interior length.
874 <title>TeleMini v1.0 Screw Terminals</title>
876 TeleMini v1.0 has four screw terminals on the end of the
877 board opposite the telemetry antenna. Two are for the apogee
878 and two are for main igniter circuits. There are also wires
879 soldered to the board for the power switch. Using the
880 picture above and starting from the top for the terminals
881 and from the left for the power switch wires, the
882 connections are as follows:
885 <title>TeleMini v1.0 Connections</title>
886 <?dbfo keep-together="always"?>
887 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
888 <colspec align='center' colwidth='*' colname='Pin #'/>
889 <colspec align='center' colwidth='2*' colname='Pin Name'/>
890 <colspec align='left' colwidth='5*' colname='Description'/>
893 <entry align='center'>Terminal #</entry>
894 <entry align='center'>Terminal Name</entry>
895 <entry align='center'>Description</entry>
901 <entry>Apogee -</entry>
902 <entry>Apogee pyro channel connection to pyro circuit</entry>
906 <entry>Apogee +</entry>
907 <entry>Apogee pyro channel common connection to battery +</entry>
911 <entry>Main -</entry>
912 <entry>Main pyro channel connection to pyro circuit</entry>
916 <entry>Main +</entry>
917 <entry>Main pyro channel common connection to battery +</entry>
921 <entry>Switch Output</entry>
922 <entry>Switch connection to flight computer</entry>
926 <entry>Switch Input</entry>
927 <entry>Switch connection to positive battery terminal</entry>
934 <title>Using a Separate Pyro Battery with TeleMini v1.0</title>
936 As described above, using an external pyro battery involves
937 connecting the negative battery terminal to the flight
938 computer ground, connecting the positive battery terminal to
939 one of the igniter leads and connecting the other igniter
940 lead to the per-channel pyro circuit connection. Because
941 there is no solid ground connection to use on TeleMini, this
945 The only available ground connection on TeleMini v1.0 are
946 the two mounting holes next to the telemetry
947 antenna. Somehow connect a small piece of wire to one of
948 those holes and hook it to the negative pyro battery terminal.
951 Connecting the positive battery terminal to the pyro
952 charges must be done separate from TeleMini v1.0, by soldering
953 them together or using some other connector.
956 The other lead from each pyro charge is then inserted into
957 the appropriate per-pyro channel screw terminal (terminal 3 for the
958 Main charge, terminal 1 for the Apogee charge).
962 <title>Using an Active Switch with TeleMini v1.0</title>
964 As explained above, an external active switch requires three
965 connections, one to the positive battery terminal, one to
966 the flight computer positive input and one to ground. Again,
967 because TeleMini doesn't have any good ground connection,
968 this is not recommended.
971 The positive battery terminal is available on the Right
972 power switch wire, the positive flight computer input is on
973 the left power switch wire. Hook a lead to either of the
974 mounting holes for a ground connection.
979 <title>TeleMini v2.0</title>
983 <imagedata fileref="telemini-v2-top.jpg" width="5.5in" scalefit="1"/>
988 TeleMini v2.0 is 0.8 inches by 1½ inches. It adds more
989 on-board data logging memory, a built-in USB connector and
990 screw terminals for the battery and power switch. The larger
991 board fits in a 24mm coupler. There's also a battery connector
992 for a LiPo battery if you want to use one of those.
995 <title>TeleMini v2.0 Screw Terminals</title>
997 TeleMini v2.0 has two sets of four screw terminals on the end of the
998 board opposite the telemetry antenna. Using the picture
999 above, the top four have connections for the main pyro
1000 circuit and an external battery and the bottom four have
1001 connections for the apogee pyro circuit and the power
1002 switch. Counting from the left, the connections are as follows:
1005 <title>TeleMini v2.0 Connections</title>
1006 <?dbfo keep-together="always"?>
1007 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
1008 <colspec align='center' colwidth='*' colname='Pin #'/>
1009 <colspec align='center' colwidth='2*' colname='Pin Name'/>
1010 <colspec align='left' colwidth='5*' colname='Description'/>
1013 <entry align='center'>Terminal #</entry>
1014 <entry align='center'>Terminal Name</entry>
1015 <entry align='center'>Description</entry>
1020 <entry>Top 1</entry>
1021 <entry>Main -</entry>
1022 <entry>Main pyro channel connection to pyro circuit</entry>
1025 <entry>Top 2</entry>
1026 <entry>Main +</entry>
1027 <entry>Main pyro channel common connection to battery +</entry>
1030 <entry>Top 3</entry>
1031 <entry>Battery +</entry>
1032 <entry>Positive external battery terminal</entry>
1035 <entry>Top 4</entry>
1036 <entry>Battery -</entry>
1037 <entry>Negative external battery terminal</entry>
1040 <entry>Bottom 1</entry>
1041 <entry>Apogee -</entry>
1042 <entry>Apogee pyro channel connection to pyro circuit</entry>
1045 <entry>Bottom 2</entry>
1046 <entry>Apogee +</entry>
1047 <entry>Apogee pyro channel common connection to
1051 <entry>Bottom 3</entry>
1052 <entry>Switch Output</entry>
1053 <entry>Switch connection to flight computer</entry>
1056 <entry>Bottom 4</entry>
1057 <entry>Switch Input</entry>
1058 <entry>Switch connection to positive battery terminal</entry>
1065 <title>Using a Separate Pyro Battery with TeleMini v2.0</title>
1067 As described above, using an external pyro battery involves
1068 connecting the negative battery terminal to the flight
1069 computer ground, connecting the positive battery terminal to
1070 one of the igniter leads and connecting the other igniter
1071 lead to the per-channel pyro circuit connection.
1074 To connect the negative pyro battery terminal to TeleMini
1075 ground, connect it to the negative external battery
1076 connection, top terminal 4.
1079 Connecting the positive battery terminal to the pyro
1080 charges must be done separate from TeleMini v2.0, by soldering
1081 them together or using some other connector.
1084 The other lead from each pyro charge is then inserted into
1085 the appropriate per-pyro channel screw terminal (top
1086 terminal 1 for the Main charge, bottom terminal 1 for the
1091 <title>Using an Active Switch with TeleMini v2.0</title>
1093 As explained above, an external active switch requires three
1094 connections, one to the positive battery terminal, one to
1095 the flight computer positive input and one to ground. Use
1096 the negative external battery connection, top terminal 4 for
1100 The positive battery terminal is available on bottom
1101 terminal 4, the positive flight computer input is on the
1107 <title>EasyMini</title>
1111 <imagedata fileref="easymini-top.jpg" width="5.5in" scalefit="1"/>
1116 EasyMini is built on a 0.8 inch by 1½ inch circuit board. It's
1117 designed to fit in a 24mm coupler tube. The connectors and
1118 screw terminals match TeleMini v2.0, so you can easily swap between
1119 EasyMini and TeleMini.
1122 <title>EasyMini Screw Terminals</title>
1124 EasyMini has two sets of four screw terminals on the end of the
1125 board opposite the telemetry antenna. Using the picture
1126 above, the top four have connections for the main pyro
1127 circuit and an external battery and the bottom four have
1128 connections for the apogee pyro circuit and the power
1129 switch. Counting from the left, the connections are as follows:
1132 <title>EasyMini Connections</title>
1133 <?dbfo keep-together="always"?>
1134 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
1135 <colspec align='center' colwidth='*' colname='Pin #'/>
1136 <colspec align='center' colwidth='2*' colname='Pin Name'/>
1137 <colspec align='left' colwidth='5*' colname='Description'/>
1140 <entry align='center'>Terminal #</entry>
1141 <entry align='center'>Terminal Name</entry>
1142 <entry align='center'>Description</entry>
1147 <entry>Top 1</entry>
1148 <entry>Main -</entry>
1149 <entry>Main pyro channel connection to pyro circuit</entry>
1152 <entry>Top 2</entry>
1153 <entry>Main +</entry>
1154 <entry>Main pyro channel common connection to battery +</entry>
1157 <entry>Top 3</entry>
1158 <entry>Battery +</entry>
1159 <entry>Positive external battery terminal</entry>
1162 <entry>Top 4</entry>
1163 <entry>Battery -</entry>
1164 <entry>Negative external battery terminal</entry>
1167 <entry>Bottom 1</entry>
1168 <entry>Apogee -</entry>
1169 <entry>Apogee pyro channel connection to pyro circuit</entry>
1172 <entry>Bottom 2</entry>
1173 <entry>Apogee +</entry>
1174 <entry>Apogee pyro channel common connection to
1178 <entry>Bottom 3</entry>
1179 <entry>Switch Output</entry>
1180 <entry>Switch connection to flight computer</entry>
1183 <entry>Bottom 4</entry>
1184 <entry>Switch Input</entry>
1185 <entry>Switch connection to positive battery terminal</entry>
1192 <title>Using a Separate Pyro Battery with EasyMini</title>
1194 As described above, using an external pyro battery involves
1195 connecting the negative battery terminal to the flight
1196 computer ground, connecting the positive battery terminal to
1197 one of the igniter leads and connecting the other igniter
1198 lead to the per-channel pyro circuit connection.
1201 To connect the negative pyro battery terminal to TeleMini
1202 ground, connect it to the negative external battery
1203 connection, top terminal 4.
1206 Connecting the positive battery terminal to the pyro
1207 charges must be done separate from EasyMini, by soldering
1208 them together or using some other connector.
1211 The other lead from each pyro charge is then inserted into
1212 the appropriate per-pyro channel screw terminal (top
1213 terminal 1 for the Main charge, bottom terminal 1 for the
1218 <title>Using an Active Switch with EasyMini</title>
1220 As explained above, an external active switch requires three
1221 connections, one to the positive battery terminal, one to
1222 the flight computer positive input and one to ground. Use
1223 the negative external battery connection, top terminal 4 for
1227 The positive battery terminal is available on bottom
1228 terminal 4, the positive flight computer input is on the
1234 <title>TeleMega</title>
1238 <imagedata fileref="telemega-v1.0-top.jpg" width="5.5in" scalefit="1"/>
1243 TeleMega is a 1¼ inch by 3¼ inch circuit board. It was
1244 designed to easily fit in a 38mm coupler. Like TeleMetrum,
1245 TeleMega has an accelerometer and so it must be mounted so that
1246 the board is aligned with the flight axis. It can be mounted
1247 either antenna up or down.
1250 <title>TeleMega Screw Terminals</title>
1252 TeleMega has two sets of nine screw terminals on the end of
1253 the board opposite the telemetry antenna. They are as follows:
1256 <title>TeleMega Screw Terminals</title>
1257 <?dbfo keep-together="always"?>
1258 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
1259 <colspec align='center' colwidth='*' colname='Pin #'/>
1260 <colspec align='center' colwidth='2*' colname='Pin Name'/>
1261 <colspec align='left' colwidth='5*' colname='Description'/>
1264 <entry align='center'>Terminal #</entry>
1265 <entry align='center'>Terminal Name</entry>
1266 <entry align='center'>Description</entry>
1271 <entry>Top 1</entry>
1272 <entry>Switch Input</entry>
1273 <entry>Switch connection to positive battery terminal</entry>
1276 <entry>Top 2</entry>
1277 <entry>Switch Output</entry>
1278 <entry>Switch connection to flight computer</entry>
1281 <entry>Top 3</entry>
1283 <entry>Ground connection for use with external active switch</entry>
1286 <entry>Top 4</entry>
1287 <entry>Main -</entry>
1288 <entry>Main pyro channel connection to pyro circuit</entry>
1291 <entry>Top 5</entry>
1292 <entry>Main +</entry>
1293 <entry>Main pyro channel common connection to battery +</entry>
1296 <entry>Top 6</entry>
1297 <entry>Apogee -</entry>
1298 <entry>Apogee pyro channel connection to pyro circuit</entry>
1301 <entry>Top 7</entry>
1302 <entry>Apogee +</entry>
1303 <entry>Apogee pyro channel common connection to battery +</entry>
1306 <entry>Top 8</entry>
1308 <entry>D pyro channel connection to pyro circuit</entry>
1311 <entry>Top 9</entry>
1313 <entry>D pyro channel common connection to battery +</entry>
1316 <entry>Bottom 1</entry>
1318 <entry>Ground connection for negative pyro battery terminal</entry>
1321 <entry>Bottom 2</entry>
1323 <entry>Positive pyro battery terminal</entry>
1326 <entry>Bottom 3</entry>
1329 Power switch output. Use to connect main battery to
1334 <entry>Bottom 4</entry>
1336 <entry>A pyro channel connection to pyro circuit</entry>
1339 <entry>Bottom 5</entry>
1341 <entry>A pyro channel common connection to battery +</entry>
1344 <entry>Bottom 6</entry>
1346 <entry>B pyro channel connection to pyro circuit</entry>
1349 <entry>Bottom 7</entry>
1351 <entry>B pyro channel common connection to battery +</entry>
1354 <entry>Bottom 8</entry>
1356 <entry>C pyro channel connection to pyro circuit</entry>
1359 <entry>Bottom 9</entry>
1361 <entry>C pyro channel common connection to battery +</entry>
1368 <title>Using a Separate Pyro Battery with TeleMega</title>
1370 TeleMega provides explicit support for an external pyro
1371 battery. All that is required is to remove the jumper
1372 between the lipo terminal (Bottom 3) and the pyro terminal
1373 (Bottom 2). Then hook the negative pyro battery terminal to ground
1374 (Bottom 1) and the positive pyro battery to the pyro battery
1375 input (Bottom 2). You can then use the existing pyro screw
1376 terminals to hook up all of the pyro charges.
1380 <title>Using Only One Battery With TeleMega</title>
1382 Because TeleMega has built-in support for a separate pyro
1383 battery, if you want to fly with just one battery running
1384 both the computer and firing the charges, you need to
1385 connect the flight computer battery to the pyro
1386 circuit. TeleMega has two screw terminals for this—hook a
1387 wire from the Lipo terminal (Bottom 3) to the Pyro terminal
1392 <title>Using an Active Switch with TeleMega</title>
1394 As explained above, an external active switch requires three
1395 connections, one to the positive battery terminal, one to
1396 the flight computer positive input and one to ground.
1399 The positive battery terminal is available on Top terminal
1400 1, the positive flight computer input is on Top terminal
1401 2. Ground is on Top terminal 3.
1406 <title>EasyMega</title>
1410 <imagedata fileref="easymega-v1.0-top.jpg" width="4.5in" scalefit="1"/>
1415 EasyMega is a 1¼ inch by 2¼ inch circuit board. It was
1416 designed to easily fit in a 38mm coupler. Like TeleMetrum,
1417 EasyMega has an accelerometer and so it must be mounted so that
1418 the board is aligned with the flight axis. It can be mounted
1419 either antenna up or down.
1422 <title>EasyMega Screw Terminals</title>
1424 EasyMega has two sets of nine screw terminals on the end of
1425 the board opposite the telemetry antenna. They are as follows:
1428 <title>EasyMega Screw Terminals</title>
1429 <?dbfo keep-together="always"?>
1430 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
1431 <colspec align='center' colwidth='*' colname='Pin #'/>
1432 <colspec align='center' colwidth='2*' colname='Pin Name'/>
1433 <colspec align='left' colwidth='5*' colname='Description'/>
1436 <entry align='center'>Terminal #</entry>
1437 <entry align='center'>Terminal Name</entry>
1438 <entry align='center'>Description</entry>
1443 <entry>Top 1</entry>
1444 <entry>Switch Input</entry>
1445 <entry>Switch connection to positive battery terminal</entry>
1448 <entry>Top 2</entry>
1449 <entry>Switch Output</entry>
1450 <entry>Switch connection to flight computer</entry>
1453 <entry>Top 3</entry>
1455 <entry>Ground connection for use with external active switch</entry>
1458 <entry>Top 4</entry>
1459 <entry>Main -</entry>
1460 <entry>Main pyro channel connection to pyro circuit</entry>
1463 <entry>Top 5</entry>
1464 <entry>Main +</entry>
1465 <entry>Main pyro channel common connection to battery +</entry>
1468 <entry>Top 6</entry>
1469 <entry>Apogee -</entry>
1470 <entry>Apogee pyro channel connection to pyro circuit</entry>
1473 <entry>Top 7</entry>
1474 <entry>Apogee +</entry>
1475 <entry>Apogee pyro channel common connection to battery +</entry>
1478 <entry>Top 8</entry>
1480 <entry>D pyro channel connection to pyro circuit</entry>
1483 <entry>Top 9</entry>
1485 <entry>D pyro channel common connection to battery +</entry>
1488 <entry>Bottom 1</entry>
1490 <entry>Ground connection for negative pyro battery terminal</entry>
1493 <entry>Bottom 2</entry>
1495 <entry>Positive pyro battery terminal</entry>
1498 <entry>Bottom 3</entry>
1501 Power switch output. Use to connect main battery to
1506 <entry>Bottom 4</entry>
1508 <entry>A pyro channel connection to pyro circuit</entry>
1511 <entry>Bottom 5</entry>
1513 <entry>A pyro channel common connection to battery +</entry>
1516 <entry>Bottom 6</entry>
1518 <entry>B pyro channel connection to pyro circuit</entry>
1521 <entry>Bottom 7</entry>
1523 <entry>B pyro channel common connection to battery +</entry>
1526 <entry>Bottom 8</entry>
1528 <entry>C pyro channel connection to pyro circuit</entry>
1531 <entry>Bottom 9</entry>
1533 <entry>C pyro channel common connection to battery +</entry>
1540 <title>Using a Separate Pyro Battery with EasyMega</title>
1542 EasyMega provides explicit support for an external pyro
1543 battery. All that is required is to remove the jumper
1544 between the lipo terminal (Bottom 3) and the pyro terminal
1545 (Bottom 2). Then hook the negative pyro battery terminal to ground
1546 (Bottom 1) and the positive pyro battery to the pyro battery
1547 input (Bottom 2). You can then use the existing pyro screw
1548 terminals to hook up all of the pyro charges.
1552 <title>Using Only One Battery With EasyMega</title>
1554 Because EasyMega has built-in support for a separate pyro
1555 battery, if you want to fly with just one battery running
1556 both the computer and firing the charges, you need to
1557 connect the flight computer battery to the pyro
1558 circuit. EasyMega has two screw terminals for this—hook a
1559 wire from the Lipo terminal (Bottom 3) to the Pyro terminal
1564 <title>Using an Active Switch with EasyMega</title>
1566 As explained above, an external active switch requires three
1567 connections, one to the positive battery terminal, one to
1568 the flight computer positive input and one to ground.
1571 The positive battery terminal is available on Top terminal
1572 1, the positive flight computer input is on Top terminal
1573 2. Ground is on Top terminal 3.
1578 <title>Flight Data Recording</title>
1580 Each flight computer logs data at 100 samples per second
1581 during ascent and 10 samples per second during descent, except
1582 for TeleMini v1.0, which records ascent at 10 samples per
1583 second and descent at 1 sample per second. Data are logged to
1584 an on-board flash memory part, which can be partitioned into
1585 several equal-sized blocks, one for each flight.
1588 <title>Data Storage on Altus Metrum altimeters</title>
1589 <?dbfo keep-together="always"?>
1590 <tgroup cols='4' align='center' colsep='1' rowsep='1'>
1591 <colspec align='center' colwidth='*' colname='Device'/>
1592 <colspec align='center' colwidth='*' colname='Bytes per sample'/>
1593 <colspec align='center' colwidth='*' colname='Total storage'/>
1594 <colspec align='center' colwidth='*' colname='Minutes of
1598 <entry align='center'>Device</entry>
1599 <entry align='center'>Bytes per Sample</entry>
1600 <entry align='center'>Total Storage</entry>
1601 <entry align='center'>Minutes at Full Rate</entry>
1606 <entry>TeleMetrum v1.0</entry>
1612 <entry>TeleMetrum v1.1 v1.2</entry>
1618 <entry>TeleMetrum v2.0</entry>
1624 <entry>TeleMini v1.0</entry>
1630 <entry>TeleMini v2.0</entry>
1636 <entry>EasyMini</entry>
1642 <entry>TeleMega</entry>
1648 <entry>EasyMega</entry>
1657 The on-board flash is partitioned into separate flight logs,
1658 each of a fixed maximum size. Increase the maximum size of
1659 each log and you reduce the number of flights that can be
1660 stored. Decrease the size and you can store more flights.
1663 Configuration data is also stored in the flash memory on
1664 TeleMetrum v1.x, TeleMini and EasyMini. This consumes 64kB
1665 of flash space. This configuration space is not available
1666 for storing flight log data. TeleMetrum v2.0, TeleMega and EasyMega
1667 store configuration data in a bit of eeprom available within
1668 the processor chip, leaving that space available in flash for
1672 To compute the amount of space needed for a single flight, you
1673 can multiply the expected ascent time (in seconds) by 100
1674 times bytes-per-sample, multiply the expected descent time (in
1675 seconds) by 10 times the bytes per sample and add the two
1676 together. That will slightly under-estimate the storage (in
1677 bytes) needed for the flight. For instance, a TeleMetrum v2.0 flight spending
1678 20 seconds in ascent and 150 seconds in descent will take
1679 about (20 * 1600) + (150 * 160) = 56000 bytes of storage. You
1680 could store dozens of these flights in the on-board flash.
1683 The default size allows for several flights on each flight
1684 computer, except for TeleMini v1.0, which only holds data for a
1685 single flight. You can adjust the size.
1688 Altus Metrum flight computers will not overwrite existing
1689 flight data, so be sure to download flight data and erase it
1690 from the flight computer before it fills up. The flight
1691 computer will still successfully control the flight even if it
1692 cannot log data, so the only thing you will lose is the data.
1696 <title>Installation</title>
1698 A typical installation involves attaching
1699 only a suitable battery, a single pole switch for
1700 power on/off, and two pairs of wires connecting e-matches for the
1701 apogee and main ejection charges. All Altus Metrum products are
1702 designed for use with single-cell batteries with 3.7 volts
1703 nominal. TeleMini v2.0 and EasyMini may also be used with other
1704 batteries as long as they supply between 4 and 12 volts.
1707 The battery connectors are a standard 2-pin JST connector and
1708 match batteries sold by Spark Fun. These batteries are
1709 single-cell Lithium Polymer batteries that nominally provide 3.7
1710 volts. Other vendors sell similar batteries for RC aircraft
1711 using mating connectors, however the polarity for those is
1712 generally reversed from the batteries used by Altus Metrum
1713 products. In particular, the Tenergy batteries supplied for use
1714 in Featherweight flight computers are not compatible with Altus
1715 Metrum flight computers or battery chargers. <emphasis>Check
1716 polarity and voltage before connecting any battery not purchased
1717 from Altus Metrum or Spark Fun.</emphasis>
1720 By default, we use the unregulated output of the battery directly
1721 to fire ejection charges. This works marvelously with standard
1722 low-current e-matches like the J-Tek from MJG Technologies, and with
1723 Quest Q2G2 igniters. However, if you want or need to use a separate
1724 pyro battery, check out the “External Pyro Battery” section in this
1725 manual for instructions on how to wire that up. The altimeters are
1726 designed to work with an external pyro battery of no more than 15 volts.
1729 Ejection charges are wired directly to the screw terminal block
1730 at the aft end of the altimeter. You'll need a very small straight
1731 blade screwdriver for these screws, such as you might find in a
1732 jeweler's screwdriver set.
1735 Except for TeleMini v1.0, the flight computers also use the
1736 screw terminal block for the power switch leads. On TeleMini v1.0,
1737 the power switch leads are soldered directly to the board and
1738 can be connected directly to a switch.
1741 For most air-frames, the integrated antennas are more than
1742 adequate. However, if you are installing in a carbon-fiber or
1743 metal electronics bay which is opaque to RF signals, you may need to
1744 use off-board external antennas instead. In this case, you can
1745 replace the stock UHF antenna wire with an edge-launched SMA connector,
1746 and, on TeleMetrum v1, you can unplug the integrated GPS
1747 antenna and select an appropriate off-board GPS antenna with
1748 cable terminating in a U.FL connector.
1753 <title>System Operation</title>
1755 <title>Firmware Modes </title>
1757 The AltOS firmware build for the altimeters has two
1758 fundamental modes, “idle” and “flight”. Which of these modes
1759 the firmware operates in is determined at start up time. For
1760 TeleMetrum, TeleMega and EasyMega, which have accelerometers, the mode is
1761 controlled by the orientation of the
1762 rocket (well, actually the board, of course...) at the time
1763 power is switched on. If the rocket is “nose up”, then
1764 the flight computer assumes it's on a rail or rod being prepared for
1765 launch, so the firmware chooses flight mode. However, if the
1766 rocket is more or less horizontal, the firmware instead enters
1767 idle mode. Since TeleMini v2.0 and EasyMini don't have an
1768 accelerometer we can use to determine orientation, “idle” mode
1769 is selected if the board is connected via USB to a computer,
1770 otherwise the board enters “flight” mode. TeleMini v1.0
1771 selects “idle” mode if it receives a command packet within the
1772 first five seconds of operation.
1775 At power on, the altimeter will beep out the battery voltage
1776 to the nearest tenth of a volt. Each digit is represented by
1777 a sequence of short “dit” beeps, with a pause between
1778 digits. A zero digit is represented with one long “dah”
1779 beep. Then there will be a short pause while the altimeter
1780 completes initialization and self test, and decides which mode
1784 Here's a short summary of all of the modes and the beeping (or
1785 flashing, in the case of TeleMini v1) that accompanies each
1786 mode. In the description of the beeping pattern, “dit” means a
1787 short beep while "dah" means a long beep (three times as
1788 long). “Brap” means a long dissonant tone.
1790 <title>AltOS Modes</title>
1791 <?dbfo keep-together="always"?>
1792 <tgroup cols='4' align='center' colsep='1' rowsep='1'>
1793 <colspec align='center' colwidth='*' colname='Mode Name'/>
1794 <colspec align='center' colwidth='*' colname='Letter'/>
1795 <colspec align='center' colwidth='*' colname='Beeps'/>
1796 <colspec align='center' colwidth='*' colname='Description'/>
1799 <entry>Mode Name</entry>
1800 <entry>Abbreviation</entry>
1801 <entry>Beeps</entry>
1802 <entry>Description</entry>
1807 <entry>Startup</entry>
1809 <entry>battery voltage in decivolts</entry>
1812 Calibrating sensors, detecting orientation.
1819 <entry>dit dit</entry>
1822 Ready to accept commands over USB or radio link.
1829 <entry>dit dah dah dit</entry>
1832 Waiting for launch. Not listening for commands.
1837 <entry>Boost</entry>
1839 <entry>dah dit dit dit</entry>
1842 Accelerating upwards.
1849 <entry>dit dit dah dit</entry>
1852 Decelerating, but moving faster than 200m/s.
1857 <entry>Coast</entry>
1859 <entry>dah dit dah dit</entry>
1862 Decelerating, moving slower than 200m/s
1867 <entry>Drogue</entry>
1869 <entry>dah dit dit</entry>
1872 Descending after apogee. Above main height.
1879 <entry>dah dah</entry>
1882 Descending. Below main height.
1887 <entry>Landed</entry>
1889 <entry>dit dah dit dit</entry>
1892 Stable altitude for at least ten seconds.
1897 <entry>Sensor error</entry>
1899 <entry>dah dit dit dah</entry>
1902 Error detected during sensor calibration.
1911 In flight or “pad” mode, the altimeter engages the flight
1912 state machine, goes into transmit-only mode to send telemetry,
1913 and waits for launch to be detected. Flight mode is indicated
1914 by an “di-dah-dah-dit” (“P” for pad) on the beeper or lights,
1915 followed by beeps or flashes indicating the state of the
1916 pyrotechnic igniter continuity. One beep/flash indicates
1917 apogee continuity, two beeps/flashes indicate main continuity,
1918 three beeps/flashes indicate both apogee and main continuity,
1919 and one longer “brap” sound which is made by rapidly
1920 alternating between two tones indicates no continuity. For a
1921 dual deploy flight, make sure you're getting three beeps or
1922 flashes before launching! For apogee-only or motor eject
1923 flights, do what makes sense.
1926 If idle mode is entered, you will hear an audible “di-dit” or
1927 see two short flashes (“I” for idle), and the flight state
1928 machine is disengaged, thus no ejection charges will fire.
1929 The altimeters also listen for the radio link when in idle
1930 mode for requests sent via TeleDongle. Commands can be issued
1931 in idle mode over either USB or the radio link
1932 equivalently. TeleMini v1.0 only has the radio link. Idle
1933 mode is useful for configuring the altimeter, for extracting
1934 data from the on-board storage chip after flight, and for
1935 ground testing pyro charges.
1938 In “Idle” and “Pad” modes, once the mode indication
1939 beeps/flashes and continuity indication has been sent, if
1940 there is no space available to log the flight in on-board
1941 memory, the flight computer will emit a warbling tone (much
1942 slower than the “no continuity tone”)
1945 Here's a summary of all of the “pad” and “idle” mode indications.
1947 <title>Pad/Idle Indications</title>
1948 <?dbfo keep-together="always"?>
1949 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
1950 <colspec align='center' colwidth='*' colname='Name'/>
1951 <colspec align='center' colwidth='*' colname='Beeps'/>
1952 <colspec align='center' colwidth='*' colname='Description'/>
1956 <entry>Beeps</entry>
1957 <entry>Description</entry>
1962 <entry>Neither</entry>
1966 No continuity detected on either apogee or main
1972 <entry>Apogee</entry>
1976 Continuity detected only on apogee igniter.
1982 <entry>dit dit</entry>
1985 Continuity detected only on main igniter.
1991 <entry>dit dit dit</entry>
1994 Continuity detected on both igniters.
1999 <entry>Storage Full</entry>
2000 <entry>warble</entry>
2003 On-board data logging storage is full. This will
2004 not prevent the flight computer from safely
2005 controlling the flight or transmitting telemetry
2006 signals, but no record of the flight will be
2007 stored in on-board flash.
2016 Once landed, the flight computer will signal that by emitting
2017 the “Landed” sound described above, after which it will beep
2018 out the apogee height (in meters). Each digit is represented
2019 by a sequence of short “dit” beeps, with a pause between
2020 digits. A zero digit is represented with one long “dah”
2021 beep. The flight computer will continue to report landed mode
2022 and beep out the maximum height until turned off.
2025 One “neat trick” of particular value when TeleMetrum, TeleMega
2026 or EasyMega are used with
2027 very large air-frames, is that you can power the board up while the
2028 rocket is horizontal, such that it comes up in idle mode. Then you can
2029 raise the air-frame to launch position, and issue a 'reset' command
2030 via TeleDongle over the radio link to cause the altimeter to reboot and
2031 come up in flight mode. This is much safer than standing on the top
2032 step of a rickety step-ladder or hanging off the side of a launch
2033 tower with a screw-driver trying to turn on your avionics before
2034 installing igniters!
2037 TeleMini v1.0 is configured solely via the radio link. Of course, that
2038 means you need to know the TeleMini radio configuration values
2039 or you won't be able to communicate with it. For situations
2040 when you don't have the radio configuration values, TeleMini v1.0
2041 offers an 'emergency recovery' mode. In this mode, TeleMini is
2042 configured as follows:
2046 Sets the radio frequency to 434.550MHz
2051 Sets the radio calibration back to the factory value.
2056 Sets the callsign to N0CALL
2061 Does not go to 'pad' mode after five seconds.
2067 To get into 'emergency recovery' mode, first find the row of
2068 four small holes opposite the switch wiring. Using a short
2069 piece of small gauge wire, connect the outer two holes
2070 together, then power TeleMini up. Once the red LED is lit,
2071 disconnect the wire and the board should signal that it's in
2072 'idle' mode after the initial five second startup period.
2078 TeleMetrum and TeleMega include a complete GPS receiver. A
2079 complete explanation of how GPS works is beyond the scope of
2080 this manual, but the bottom line is that the GPS receiver
2081 needs to lock onto at least four satellites to obtain a solid
2082 3 dimensional position fix and know what time it is.
2085 The flight computers provide backup power to the GPS chip any time a
2086 battery is connected. This allows the receiver to “warm start” on
2087 the launch rail much faster than if every power-on were a GPS
2088 “cold start”. In typical operations, powering up
2089 on the flight line in idle mode while performing final air-frame
2090 preparation will be sufficient to allow the GPS receiver to cold
2091 start and acquire lock. Then the board can be powered down during
2092 RSO review and installation on a launch rod or rail. When the board
2093 is turned back on, the GPS system should lock very quickly, typically
2094 long before igniter installation and return to the flight line are
2099 <title>Controlling An Altimeter Over The Radio Link</title>
2101 One of the unique features of the Altus Metrum system is the
2102 ability to create a two way command link between TeleDongle
2103 and an altimeter using the digital radio transceivers
2104 built into each device. This allows you to interact with the
2105 altimeter from afar, as if it were directly connected to the
2109 Any operation which can be performed with a flight computer can
2110 either be done with the device directly connected to the
2111 computer via the USB cable, or through the radio
2112 link. TeleMini v1.0 doesn't provide a USB connector and so it is
2113 always communicated with over radio. Select the appropriate
2114 TeleDongle device when the list of devices is presented and
2115 AltosUI will interact with an altimeter over the radio link.
2118 One oddity in the current interface is how AltosUI selects the
2119 frequency for radio communications. Instead of providing
2120 an interface to specifically configure the frequency, it uses
2121 whatever frequency was most recently selected for the target
2122 TeleDongle device in Monitor Flight mode. If you haven't ever
2123 used that mode with the TeleDongle in question, select the
2124 Monitor Flight button from the top level UI, and pick the
2125 appropriate TeleDongle device. Once the flight monitoring
2126 window is open, select the desired frequency and then close it
2127 down again. All radio communications will now use that frequency.
2132 Save Flight Data—Recover flight data from the rocket without
2138 Configure altimeter apogee delays, main deploy heights
2139 and additional pyro event conditions
2140 to respond to changing launch conditions. You can also
2141 'reboot' the altimeter. Use this to remotely enable the
2142 flight computer by turning TeleMetrum or TeleMega on in “idle” mode,
2143 then once the air-frame is oriented for launch, you can
2144 reboot the altimeter and have it restart in pad mode
2145 without having to climb the scary ladder.
2150 Fire Igniters—Test your deployment charges without snaking
2151 wires out through holes in the air-frame. Simply assemble the
2152 rocket as if for flight with the apogee and main charges
2153 loaded, then remotely command the altimeter to fire the
2159 Operation over the radio link for configuring an altimeter, ground
2160 testing igniters, and so forth uses the same RF frequencies as flight
2161 telemetry. To configure the desired TeleDongle frequency, select
2162 the monitor flight tab, then use the frequency selector and
2163 close the window before performing other desired radio operations.
2166 The flight computers only enable radio commanding in 'idle' mode.
2167 TeleMetrum and TeleMega use the accelerometer to detect which orientation they
2168 start up in, so make sure you have the flight computer lying horizontally when you turn
2169 it on. Otherwise, it will start in 'pad' mode ready for
2170 flight, and will not be listening for command packets from TeleDongle.
2173 TeleMini listens for a command packet for five seconds after
2174 first being turned on, if it doesn't hear anything, it enters
2175 'pad' mode, ready for flight and will no longer listen for
2176 command packets. The easiest way to connect to TeleMini is to
2177 initiate the command and select the TeleDongle device. At this
2178 point, the TeleDongle will be attempting to communicate with
2179 the TeleMini. Now turn TeleMini on, and it should immediately
2180 start communicating with the TeleDongle and the desired
2181 operation can be performed.
2184 You can monitor the operation of the radio link by watching the
2185 lights on the devices. The red LED will flash each time a packet
2186 is transmitted, while the green LED will light up on TeleDongle when
2187 it is waiting to receive a packet from the altimeter.
2191 <title>Ground Testing </title>
2193 An important aspect of preparing a rocket using electronic deployment
2194 for flight is ground testing the recovery system. Thanks
2195 to the bi-directional radio link central to the Altus Metrum system,
2196 this can be accomplished in a TeleMega, TeleMetrum or TeleMini equipped rocket
2197 with less work than you may be accustomed to with other systems. It
2201 Just prep the rocket for flight, then power up the altimeter
2202 in “idle” mode (placing air-frame horizontal for TeleMetrum or TeleMega, or
2203 selecting the Configure Altimeter tab for TeleMini). This will cause
2204 the firmware to go into “idle” mode, in which the normal flight
2205 state machine is disabled and charges will not fire without
2206 manual command. You can now command the altimeter to fire the apogee
2207 or main charges from a safe distance using your computer and
2208 TeleDongle and the Fire Igniter tab to complete ejection testing.
2212 <title>Radio Link </title>
2214 Our flight computers all incorporate an RF transceiver, but
2215 it's not a full duplex system... each end can only be transmitting or
2216 receiving at any given moment. So we had to decide how to manage the
2220 By design, the altimeter firmware listens for the radio link when
2221 it's in “idle mode”, which
2222 allows us to use the radio link to configure the rocket, do things like
2223 ejection tests, and extract data after a flight without having to
2224 crack open the air-frame. However, when the board is in “flight
2225 mode”, the altimeter only
2226 transmits and doesn't listen at all. That's because we want to put
2227 ultimate priority on event detection and getting telemetry out of
2229 the radio in case the rocket crashes and we aren't able to extract
2233 We don't generally use a 'normal packet radio' mode like APRS
2234 because they're just too inefficient. The GFSK modulation we
2235 use is FSK with the base-band pulses passed through a Gaussian
2236 filter before they go into the modulator to limit the
2237 transmitted bandwidth. When combined with forward error
2238 correction and interleaving, this allows us to have a very
2239 robust 19.2 kilobit data link with only 10-40 milliwatts of
2240 transmit power, a whip antenna in the rocket, and a hand-held
2241 Yagi on the ground. We've had flights to above 21k feet AGL
2242 with great reception, and calculations suggest we should be
2243 good to well over 40k feet AGL with a 5-element yagi on the
2244 ground with our 10mW units and over 100k feet AGL with the
2245 40mW devices. We hope to fly boards to higher altitudes over
2246 time, and would of course appreciate customer feedback on
2247 performance in higher altitude flights!
2253 TeleMetrum v2.0 and TeleMega can send APRS if desired, and the
2254 interval between APRS packets can be configured. As each APRS
2255 packet takes a full second to transmit, we recommend an
2256 interval of at least 5 seconds to avoid consuming too much
2257 battery power or radio channel bandwidth. You can configure
2258 the APRS interval using AltosUI; that process is described in
2259 the Configure Altimeter section of the AltosUI chapter.
2262 AltOS uses the APRS compressed position report data format,
2263 which provides for higher position precision and shorter
2264 packets than the original APRS format. It also includes
2265 altitude data, which is invaluable when tracking rockets. We
2266 haven't found a receiver which doesn't handle compressed
2267 positions, but it's just possible that you have one, so if you
2268 have an older device that can receive the raw packets but
2269 isn't displaying position information, it's possible that this
2273 APRS packets include an SSID (Secondary Station Identifier)
2274 field that allows one operator to have multiple
2275 transmitters. AltOS allows you to set this to a single digit
2276 from 0 to 9, allowing you to fly multiple transmitters at the
2277 same time while keeping the identify of each one separate in
2278 the receiver. By default, the SSID is set to the last digit of
2279 the device serial number.
2282 The APRS packet format includes a comment field that can have
2283 arbitrary text in it. AltOS uses this to send status
2284 information about the flight computer. It sends four fields as
2285 shown in the following table.
2288 <title>Altus Metrum APRS Comments</title>
2289 <?dbfo keep-together="always"?>
2290 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
2291 <colspec align='center' colwidth='*' colname='Field'/>
2292 <colspec align='center' colwidth='*' colname='Example'/>
2293 <colspec align='center' colwidth='4*' colname='Description'/>
2296 <entry align='center'>Field</entry>
2297 <entry align='center'>Example</entry>
2298 <entry align='center'>Description</entry>
2305 <entry>GPS Status U for unlocked, L for locked</entry>
2310 <entry>Number of Satellites in View</entry>
2315 <entry>Altimeter Battery Voltage</entry>
2320 <entry>Apogee Igniter Voltage</entry>
2325 <entry>Main Igniter Voltage</entry>
2330 <entry>Device Serial Number</entry>
2336 Here's an example of an APRS comment showing GPS lock with 6
2337 satellites in view, a primary battery at 4.0V, and
2338 apogee and main igniters both at 3.7V from device 1286.
2340 L6 B4.0 A3.7 M3.7 1286
2344 Make sure your primary battery is above 3.8V, any connected
2345 igniters are above 3.5V and GPS is locked with at least 5 or 6
2346 satellites in view before flying. If GPS is switching between
2347 L and U regularly, then it doesn't have a good lock and you
2348 should wait until it becomes stable.
2351 If the GPS receiver loses lock, the APRS data transmitted will
2352 contain the last position for which GPS lock was
2353 available. You can tell that this has happened by noticing
2354 that the GPS status character switches from 'L' to 'U'. Before
2355 GPS has locked, APRS will transmit zero for latitude,
2356 longitude and altitude.
2360 <title>Configurable Parameters</title>
2362 Configuring an Altus Metrum altimeter for flight is very
2363 simple. Even on our baro-only TeleMini and EasyMini boards,
2364 the use of a Kalman filter means there is no need to set a
2365 “mach delay”. The few configurable parameters can all be set
2366 using AltosUI over USB or or radio link via TeleDongle. Read
2367 the Configure Altimeter section in the AltosUI chapter below
2368 for more information.
2371 <title>Radio Frequency</title>
2373 Altus Metrum boards support radio frequencies in the 70cm
2374 band. By default, the configuration interface provides a
2375 list of 10 “standard” frequencies in 100kHz channels starting at
2376 434.550MHz. However, the firmware supports use of
2377 any 50kHz multiple within the 70cm band. At any given
2378 launch, we highly recommend coordinating when and by whom each
2379 frequency will be used to avoid interference. And of course, both
2380 altimeter and TeleDongle must be configured to the same
2381 frequency to successfully communicate with each other.
2385 <title>Callsign</title>
2387 This sets the callsign used for telemetry, APRS and the
2388 packet link. For telemetry and APRS, this is used to
2389 identify the device. For the packet link, the callsign must
2390 match that configured in AltosUI or the link will not
2391 work. This is to prevent accidental configuration of another
2392 Altus Metrum flight computer operating on the same frequency nearby.
2396 <title>Telemetry/RDF/APRS Enable</title>
2398 You can completely disable the radio while in flight, if
2399 necessary. This doesn't disable the packet link in idle
2404 <title>Telemetry baud rate</title>
2406 This sets the modulation bit rate for data transmission for
2407 both telemetry and packet link mode. Lower bit
2408 rates will increase range while reducing the amount of data
2409 that can be sent and increasing battery consumption. All
2410 telemetry is done using a rate 1/2 constraint 4 convolution
2411 code, so the actual data transmission rate is 1/2 of the
2412 modulation bit rate specified here.
2416 <title>APRS Interval</title>
2418 This selects how often APRS packets are transmitted. Set
2419 this to zero to disable APRS without also disabling the
2420 regular telemetry and RDF transmissions. As APRS takes a
2421 full second to transmit a single position report, we
2422 recommend sending packets no more than once every 5 seconds.
2426 <title>APRS SSID</title>
2428 This selects the SSID reported in APRS packets. By default,
2429 it is set to the last digit of the serial number, but you
2430 can change this to any value from 0 to 9.
2434 <title>Apogee Delay</title>
2436 Apogee delay is the number of seconds after the altimeter detects flight
2437 apogee that the drogue charge should be fired. In most cases, this
2438 should be left at the default of 0. However, if you are flying
2439 redundant electronics such as for an L3 certification, you may wish
2440 to set one of your altimeters to a positive delay so that both
2441 primary and backup pyrotechnic charges do not fire simultaneously.
2444 The Altus Metrum apogee detection algorithm fires exactly at
2445 apogee. If you are also flying an altimeter like the
2446 PerfectFlite MAWD, which only supports selecting 0 or 1
2447 seconds of apogee delay, you may wish to set the MAWD to 0
2448 seconds delay and set the TeleMetrum to fire your backup 2
2449 or 3 seconds later to avoid any chance of both charges
2450 firing simultaneously. We've flown several air-frames this
2451 way quite happily, including Keith's successful L3 cert.
2455 <title>Apogee Lockout</title>
2457 Apogee lockout is the number of seconds after boost where
2458 the flight computer will not fire the apogee charge, even if
2459 the rocket appears to be at apogee. This is often called
2460 'Mach Delay', as it is intended to prevent a flight computer
2461 from unintentionally firing apogee charges due to the pressure
2462 spike that occurrs across a mach transition. Altus Metrum
2463 flight computers include a Kalman filter which is not fooled
2464 by this sharp pressure increase, and so this setting should
2465 be left at the default value of zero to disable it.
2469 <title>Main Deployment Altitude</title>
2471 By default, the altimeter will fire the main deployment charge at an
2472 elevation of 250 meters (about 820 feet) above ground. We think this
2473 is a good elevation for most air-frames, but feel free to change this
2474 to suit. In particular, if you are flying two altimeters, you may
2476 deployment elevation for the backup altimeter to be something lower
2477 than the primary so that both pyrotechnic charges don't fire
2482 <title>Maximum Flight Log</title>
2484 Changing this value will set the maximum amount of flight
2485 log storage that an individual flight will use. The
2486 available storage is divided into as many flights of the
2487 specified size as can fit in the available space. You can
2488 download and erase individual flight logs. If you fill up
2489 the available storage, future flights will not get logged
2490 until you erase some of the stored ones.
2493 Even though our flight computers (except TeleMini v1.0) can store
2494 multiple flights, we strongly recommend downloading and saving
2495 flight data after each flight.
2499 <title>Ignite Mode</title>
2501 Instead of firing one charge at apogee and another charge at
2502 a fixed height above the ground, you can configure the
2503 altimeter to fire both at apogee or both during
2504 descent. This was added to support an airframe Bdale designed that
2505 had two altimeters, one in the fin can and one in the nose.
2508 Providing the ability to use both igniters for apogee or
2509 main allows some level of redundancy without needing two
2510 flight computers. In Redundant Apogee or Redundant Main
2511 mode, the two charges will be fired two seconds apart.
2515 <title>Pad Orientation</title>
2517 TeleMetrum, TeleMega and EasyMega measure acceleration along the axis
2518 of the board. Which way the board is oriented affects the
2519 sign of the acceleration value. Instead of trying to guess
2520 which way the board is mounted in the air frame, the
2521 altimeter must be explicitly configured for either Antenna
2522 Up or Antenna Down. The default, Antenna Up, expects the end
2523 of the board connected to the 70cm antenna to be nearest the
2524 nose of the rocket, with the end containing the screw
2525 terminals nearest the tail.
2529 <title>Configurable Pyro Channels</title>
2531 In addition to the usual Apogee and Main pyro channels,
2532 TeleMega and EasyMega have four additional channels that can be configured
2533 to activate when various flight conditions are
2534 satisfied. You can select as many conditions as necessary;
2535 all of them must be met in order to activate the
2536 channel. The conditions available are:
2541 Acceleration away from the ground. Select a value, and
2542 then choose whether acceleration should be above or
2543 below that value. Acceleration is positive upwards, so
2544 accelerating towards the ground would produce negative
2545 numbers. Acceleration during descent is noisy and
2546 inaccurate, so be careful when using it during these
2547 phases of the flight.
2552 Vertical speed. Select a value, and then choose whether
2553 vertical speed should be above or below that
2554 value. Speed is positive upwards, so moving towards the
2555 ground would produce negative numbers. Speed during
2556 descent is a bit noisy and so be careful when using it
2557 during these phases of the flight.
2562 Height. Select a value, and then choose whether the
2563 height above the launch pad should be above or below
2569 Orientation. TeleMega and EasyMega contain a 3-axis gyroscope and
2570 accelerometer which is used to measure the current
2571 angle. Note that this angle is not the change in angle
2572 from the launch pad, but rather absolute relative to
2573 gravity; the 3-axis accelerometer is used to compute the
2574 angle of the rocket on the launch pad and initialize the
2575 system. Because this value is computed by integrating
2576 rate gyros, it gets progressively less accurate as the
2577 flight goes on. It should have an accumulated error of
2578 less than 0.2°/second (after 10 seconds of flight, the
2579 error should be less than 2°).
2582 The usual use of the orientation configuration is to
2583 ensure that the rocket is traveling mostly upwards when
2584 deciding whether to ignite air starts or additional
2585 stages. For that, choose a reasonable maximum angle
2586 (like 20°) and set the motor igniter to require an angle
2587 of less than that value.
2592 Flight Time. Time since boost was detected. Select a
2593 value and choose whether to activate the pyro channel
2594 before or after that amount of time.
2599 Ascending. A simple test saying whether the rocket is
2600 going up or not. This is exactly equivalent to testing
2601 whether the speed is > 0.
2606 Descending. A simple test saying whether the rocket is
2607 going down or not. This is exactly equivalent to testing
2608 whether the speed is < 0.
2613 After Motor. The flight software counts each time the
2614 rocket starts accelerating (presumably due to a motor or
2615 motors igniting). Use this value to count ignitions for
2616 multi-staged or multi-airstart launches.
2621 Delay. This value doesn't perform any checks, instead it
2622 inserts a delay between the time when the other
2623 parameters become true and when the pyro channel is
2629 Flight State. The flight software tracks the flight
2630 through a sequence of states:
2634 Boost. The motor has lit and the rocket is
2635 accelerating upwards.
2640 Fast. The motor has burned out and the rocket is
2641 decelerating, but it is going faster than 200m/s.
2646 Coast. The rocket is still moving upwards and
2647 decelerating, but the speed is less than 200m/s.
2652 Drogue. The rocket has reached apogee and is heading
2653 back down, but is above the configured Main
2659 Main. The rocket is still descending, and is below
2665 Landed. The rocket is no longer moving.
2671 You can select a state to limit when the pyro channel
2672 may activate; note that the check is based on when the
2673 rocket transitions <emphasis>into</emphasis> the state, and so checking for
2674 “greater than Boost” means that the rocket is currently
2675 in boost or some later state.
2678 When a motor burns out, the rocket enters either Fast or
2679 Coast state (depending on how fast it is moving). If the
2680 computer detects upwards acceleration again, it will
2681 move back to Boost state.
2690 <title>AltosUI</title>
2694 <imagedata fileref="altosui.png" width="4.6in"/>
2699 The AltosUI program provides a graphical user interface for
2700 interacting with the Altus Metrum product family. AltosUI can
2701 monitor telemetry data, configure devices and many other
2702 tasks. The primary interface window provides a selection of
2703 buttons, one for each major activity in the system. This chapter
2704 is split into sections, each of which documents one of the tasks
2705 provided from the top-level toolbar.
2708 <title>Monitor Flight</title>
2709 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
2711 Selecting this item brings up a dialog box listing all of the
2712 connected TeleDongle devices. When you choose one of these,
2713 AltosUI will create a window to display telemetry data as
2714 received by the selected TeleDongle device.
2719 <imagedata fileref="device-selection.png" width="3.1in"/>
2724 All telemetry data received are automatically recorded in
2725 suitable log files. The name of the files includes the current
2726 date and rocket serial and flight numbers.
2729 The radio frequency being monitored by the TeleDongle device is
2730 displayed at the top of the window. You can configure the
2731 frequency by clicking on the frequency box and selecting the desired
2732 frequency. AltosUI remembers the last frequency selected for each
2733 TeleDongle and selects that automatically the next time you use
2737 Below the TeleDongle frequency selector, the window contains a few
2738 significant pieces of information about the altimeter providing
2739 the telemetry data stream:
2743 <para>The configured call-sign</para>
2746 <para>The device serial number</para>
2749 <para>The flight number. Each altimeter remembers how many
2755 The rocket flight state. Each flight passes through several
2756 states including Pad, Boost, Fast, Coast, Drogue, Main and
2762 The Received Signal Strength Indicator value. This lets
2763 you know how strong a signal TeleDongle is receiving. The
2764 radio inside TeleDongle operates down to about -99dBm;
2765 weaker signals may not be receivable. The packet link uses
2766 error detection and correction techniques which prevent
2767 incorrect data from being reported.
2772 The age of the displayed data, in seconds since the last
2773 successfully received telemetry packet. In normal operation
2774 this will stay in the low single digits. If the number starts
2775 counting up, then you are no longer receiving data over the radio
2776 link from the flight computer.
2781 Finally, the largest portion of the window contains a set of
2782 tabs, each of which contain some information about the rocket.
2783 They're arranged in 'flight order' so that as the flight
2784 progresses, the selected tab automatically switches to display
2785 data relevant to the current state of the flight. You can select
2786 other tabs at any time. The final 'table' tab displays all of
2787 the raw telemetry values in one place in a spreadsheet-like format.
2790 <title>Launch Pad</title>
2794 <imagedata fileref="launch-pad.png" width="5.5in"/>
2799 The 'Launch Pad' tab shows information used to decide when the
2800 rocket is ready for flight. The first elements include red/green
2801 indicators, if any of these is red, you'll want to evaluate
2802 whether the rocket is ready to launch:
2805 <term>Battery Voltage</term>
2808 This indicates whether the Li-Po battery powering the
2809 flight computer has sufficient charge to last for
2810 the duration of the flight. A value of more than
2811 3.8V is required for a 'GO' status.
2816 <term>Apogee Igniter Voltage</term>
2819 This indicates whether the apogee
2820 igniter has continuity. If the igniter has a low
2821 resistance, then the voltage measured here will be close
2822 to the Li-Po battery voltage. A value greater than 3.2V is
2823 required for a 'GO' status.
2828 <term>Main Igniter Voltage</term>
2831 This indicates whether the main
2832 igniter has continuity. If the igniter has a low
2833 resistance, then the voltage measured here will be close
2834 to the Li-Po battery voltage. A value greater than 3.2V is
2835 required for a 'GO' status.
2840 <term>On-board Data Logging</term>
2843 This indicates whether there is
2844 space remaining on-board to store flight data for the
2845 upcoming flight. If you've downloaded data, but failed
2846 to erase flights, there may not be any space
2847 left. Most of our flight computers can store multiple
2848 flights, depending on the configured maximum flight log
2849 size. TeleMini v1.0 stores only a single flight, so it
2851 downloaded and erased after each flight to capture
2852 data. This only affects on-board flight logging; the
2853 altimeter will still transmit telemetry and fire
2854 ejection charges at the proper times even if the flight
2855 data storage is full.
2860 <term>GPS Locked</term>
2863 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
2864 currently able to compute position information. GPS requires
2865 at least 4 satellites to compute an accurate position.
2870 <term>GPS Ready</term>
2873 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
2874 10 consecutive positions without losing lock. This ensures
2875 that the GPS receiver has reliable reception from the
2883 The Launchpad tab also shows the computed launch pad position
2884 and altitude, averaging many reported positions to improve the
2885 accuracy of the fix.
2889 <title>Ascent</title>
2893 <imagedata fileref="ascent.png" width="5.5in"/>
2898 This tab is shown during Boost, Fast and Coast
2899 phases. The information displayed here helps monitor the
2900 rocket as it heads towards apogee.
2903 The height, speed, acceleration and tilt are shown along
2904 with the maximum values for each of them. This allows you to
2905 quickly answer the most commonly asked questions you'll hear
2909 The current latitude and longitude reported by the GPS are
2910 also shown. Note that under high acceleration, these values
2911 may not get updated as the GPS receiver loses position
2912 fix. Once the rocket starts coasting, the receiver should
2913 start reporting position again.
2916 Finally, the current igniter voltages are reported as in the
2917 Launch Pad tab. This can help diagnose deployment failures
2918 caused by wiring which comes loose under high acceleration.
2922 <title>Descent</title>
2926 <imagedata fileref="descent.png" width="5.5in"/>
2931 Once the rocket has reached apogee and (we hope) activated the
2932 apogee charge, attention switches to tracking the rocket on
2933 the way back to the ground, and for dual-deploy flights,
2934 waiting for the main charge to fire.
2937 To monitor whether the apogee charge operated correctly, the
2938 current descent rate is reported along with the current
2939 height. Good descent rates vary based on the choice of recovery
2940 components, but generally range from 15-30m/s on drogue and should
2941 be below 10m/s when under the main parachute in a dual-deploy flight.
2944 With GPS-equipped flight computers, you can locate the rocket in the
2945 sky using the elevation and bearing information to figure
2946 out where to look. Elevation is in degrees above the
2947 horizon. Bearing is reported in degrees relative to true
2948 north. Range can help figure out how big the rocket will
2949 appear. Ground Distance shows how far it is to a point
2950 directly under the rocket and can help figure out where the
2951 rocket is likely to land. Note that all of these values are
2952 relative to the pad location. If the elevation is near 90°,
2953 the rocket is over the pad, not over you.
2956 Finally, the igniter voltages are reported in this tab as
2957 well, both to monitor the main charge as well as to see what
2958 the status of the apogee charge is. Note that some commercial
2959 e-matches are designed to retain continuity even after being
2960 fired, and will continue to show as green or return from red to
2965 <title>Landed</title>
2969 <imagedata fileref="landed.png" width="5.5in"/>
2974 Once the rocket is on the ground, attention switches to
2975 recovery. While the radio signal is often lost once the
2976 rocket is on the ground, the last reported GPS position is
2977 generally within a short distance of the actual landing location.
2980 The last reported GPS position is reported both by
2981 latitude and longitude as well as a bearing and distance from
2982 the launch pad. The distance should give you a good idea of
2983 whether to walk or hitch a ride. Take the reported
2984 latitude and longitude and enter them into your hand-held GPS
2985 unit and have that compute a track to the landing location.
2988 Our flight computers will continue to transmit RDF
2989 tones after landing, allowing you to locate the rocket by
2990 following the radio signal if necessary. You may need to get
2991 away from the clutter of the flight line, or even get up on
2992 a hill (or your neighbor's RV roof) to receive the RDF signal.
2995 The maximum height, speed and acceleration reported
2996 during the flight are displayed for your admiring observers.
2997 The accuracy of these immediate values depends on the quality
2998 of your radio link and how many packets were received.
2999 Recovering the on-board data after flight may yield
3000 more precise results.
3003 To get more detailed information about the flight, you can
3004 click on the 'Graph Flight' button which will bring up a
3005 graph window for the current flight.
3009 <title>Table</title>
3013 <imagedata fileref="table.png" width="5.5in"/>
3018 The table view shows all of the data available from the
3019 flight computer. Probably the most useful data on
3020 this tab is the detailed GPS information, which includes
3021 horizontal dilution of precision information, and
3022 information about the signal being received from the satellites.
3026 <title>Site Map</title>
3030 <imagedata fileref="site-map.png" width="5.5in"/>
3035 When the TeleMetrum has a GPS fix, the Site Map tab will map
3036 the rocket's position to make it easier for you to locate the
3037 rocket, both while it is in the air, and when it has landed. The
3038 rocket's state is indicated by color: white for pad, red for
3039 boost, pink for fast, yellow for coast, light blue for drogue,
3040 dark blue for main, and black for landed.
3043 The map's default scale is approximately 3m (10ft) per pixel. The map
3044 can be dragged using the left mouse button. The map will attempt
3045 to keep the rocket roughly centered while data is being received.
3048 You can adjust the style of map and the zoom level with
3049 buttons on the right side of the map window. You can draw a
3050 line on the map by moving the mouse over the map with a
3051 button other than the left one pressed, or by pressing the
3052 left button while also holding down the shift key. The
3053 length of the line in real-world units will be shown at the
3057 Images are fetched automatically via the Google Maps Static API,
3058 and cached on disk for reuse. If map images cannot be downloaded,
3059 the rocket's path will be traced on a dark gray background
3063 You can pre-load images for your favorite launch sites
3064 before you leave home; check out the 'Preload Maps' section below.
3068 <title>Ignitor</title>
3072 <imagedata fileref="ignitor.png" width="5.5in"/>
3077 TeleMega includes four additional programmable pyro
3078 channels. The Ignitor tab shows whether each of them has
3079 continuity. If an ignitor has a low resistance, then the
3080 voltage measured here will be close to the pyro battery
3081 voltage. A value greater than 3.2V is required for a 'GO'
3087 <title>Save Flight Data</title>
3089 The altimeter records flight data to its internal flash memory.
3090 TeleMetrum data is recorded at a much higher rate than the telemetry
3091 system can handle, and is not subject to radio drop-outs. As
3092 such, it provides a more complete and precise record of the
3093 flight. The 'Save Flight Data' button allows you to read the
3094 flash memory and write it to disk.
3097 Clicking on the 'Save Flight Data' button brings up a list of
3098 connected flight computers and TeleDongle devices. If you select a
3099 flight computer, the flight data will be downloaded from that
3100 device directly. If you select a TeleDongle device, flight data
3101 will be downloaded from a flight computer over radio link via the
3102 specified TeleDongle. See the chapter on Controlling An Altimeter
3103 Over The Radio Link for more information.
3106 After the device has been selected, a dialog showing the
3107 flight data saved in the device will be shown allowing you to
3108 select which flights to download and which to delete. With
3109 version 0.9 or newer firmware, you must erase flights in order
3110 for the space they consume to be reused by another
3111 flight. This prevents accidentally losing flight data
3112 if you neglect to download data before flying again. Note that
3113 if there is no more space available in the device, then no
3114 data will be recorded during the next flight.
3117 The file name for each flight log is computed automatically
3118 from the recorded flight date, altimeter serial number and
3119 flight number information.
3123 <title>Replay Flight</title>
3125 Select this button and you are prompted to select a flight
3126 record file, either a .telem file recording telemetry data or a
3127 .eeprom file containing flight data saved from the altimeter
3131 Once a flight record is selected, the flight monitor interface
3132 is displayed and the flight is re-enacted in real time. Check
3133 the Monitor Flight chapter above to learn how this window operates.
3137 <title>Graph Data</title>
3139 Select this button and you are prompted to select a flight
3140 record file, either a .telem file recording telemetry data or a
3141 .eeprom file containing flight data saved from
3145 Note that telemetry files will generally produce poor graphs
3146 due to the lower sampling rate and missed telemetry packets.
3147 Use saved flight data in .eeprom files for graphing where possible.
3150 Once a flight record is selected, a window with multiple tabs is
3154 <title>Flight Graph</title>
3158 <imagedata fileref="graph.png" width="6in" scalefit="1"/>
3163 By default, the graph contains acceleration (blue),
3164 velocity (green) and altitude (red).
3167 The graph can be zoomed into a particular area by clicking and
3168 dragging down and to the right. Once zoomed, the graph can be
3169 reset by clicking and dragging up and to the left. Holding down
3170 control and clicking and dragging allows the graph to be panned.
3171 The right mouse button causes a pop-up menu to be displayed, giving
3172 you the option save or print the plot.
3176 <title>Configure Graph</title>
3180 <imagedata fileref="graph-configure.png" width="6in" scalefit="1"/>
3185 This selects which graph elements to show, and, at the
3186 very bottom, lets you switch between metric and
3191 <title>Flight Statistics</title>
3195 <imagedata fileref="graph-stats.png" width="6in" scalefit="1"/>
3200 Shows overall data computed from the flight.
3208 <imagedata fileref="graph-map.png" width="6in" scalefit="1"/>
3213 Shows a satellite image of the flight area overlaid
3214 with the path of the flight. The red concentric
3215 circles mark the launch pad, the black concentric
3216 circles mark the landing location.
3221 <title>Export Data</title>
3223 This tool takes the raw data files and makes them available for
3224 external analysis. When you select this button, you are prompted to
3225 select a flight data file, which can be either a .eeprom or .telem.
3226 The .eeprom files contain higher resolution and more continuous data,
3227 while .telem files contain receiver signal strength information.
3228 Next, a second dialog appears which is used to select
3229 where to write the resulting file. It has a selector to choose
3230 between CSV and KML file formats.
3233 <title>Comma Separated Value Format</title>
3235 This is a text file containing the data in a form suitable for
3236 import into a spreadsheet or other external data analysis
3237 tool. The first few lines of the file contain the version and
3238 configuration information from the altimeter, then
3239 there is a single header line which labels all of the
3240 fields. All of these lines start with a '#' character which
3241 many tools can be configured to skip over.
3244 The remaining lines of the file contain the data, with each
3245 field separated by a comma and at least one space. All of
3246 the sensor values are converted to standard units, with the
3247 barometric data reported in both pressure, altitude and
3248 height above pad units.
3252 <title>Keyhole Markup Language (for Google Earth)</title>
3254 This is the format used by Google Earth to provide an overlay
3255 within that application. With this, you can use Google Earth to
3256 see the whole flight path in 3D.
3261 <title>Configure Altimeter</title>
3265 <imagedata fileref="configure-altimeter.png" width="3.6in" scalefit="1"/>
3270 Select this button and then select either an altimeter or
3271 TeleDongle Device from the list provided. Selecting a TeleDongle
3272 device will use the radio link to configure a remote altimeter.
3275 The first few lines of the dialog provide information about the
3276 connected device, including the product name,
3277 software version and hardware serial number. Below that are the
3278 individual configuration entries.
3281 At the bottom of the dialog, there are four buttons:
3288 This writes any changes to the
3289 configuration parameter block in flash memory. If you don't
3290 press this button, any changes you make will be lost.
3298 This resets the dialog to the most recently saved values,
3299 erasing any changes you have made.
3307 This reboots the device. Use this to
3308 switch from idle to pad mode by rebooting once the rocket is
3309 oriented for flight, or to confirm changes you think you saved
3318 This closes the dialog. Any unsaved changes will be
3325 The rest of the dialog contains the parameters to be configured.
3328 <title>Main Deploy Altitude</title>
3330 This sets the altitude (above the recorded pad altitude) at
3331 which the 'main' igniter will fire. The drop-down menu shows
3332 some common values, but you can edit the text directly and
3333 choose whatever you like. If the apogee charge fires below
3334 this altitude, then the main charge will fire two seconds
3335 after the apogee charge fires.
3339 <title>Apogee Delay</title>
3341 When flying redundant electronics, it's often important to
3342 ensure that multiple apogee charges don't fire at precisely
3343 the same time, as that can over pressurize the apogee deployment
3344 bay and cause a structural failure of the air-frame. The Apogee
3345 Delay parameter tells the flight computer to fire the apogee
3346 charge a certain number of seconds after apogee has been
3351 <title>Apogee Lockoug</title>
3353 Apogee lockout is the number of seconds after boost where
3354 the flight computer will not fire the apogee charge, even if
3355 the rocket appears to be at apogee. This is often called
3356 'Mach Delay', as it is intended to prevent a flight computer
3357 from unintentionally firing apogee charges due to the pressure
3358 spike that occurrs across a mach transition. Altus Metrum
3359 flight computers include a Kalman filter which is not fooled
3360 by this sharp pressure increase, and so this setting should
3361 be left at the default value of zero to disable it.
3365 <title>Frequency</title>
3367 This configures which of the frequencies to use for both
3368 telemetry and packet command mode. Note that if you set this
3369 value via packet command mode, the TeleDongle frequency will
3370 also be automatically reconfigured to match so that
3371 communication will continue afterwards.
3375 <title>RF Calibration</title>
3377 The radios in every Altus Metrum device are calibrated at the
3378 factory to ensure that they transmit and receive on the
3379 specified frequency. If you need to you can adjust the calibration
3380 by changing this value. Do not do this without understanding what
3381 the value means, read the appendix on calibration and/or the source
3382 code for more information. To change a TeleDongle's calibration,
3383 you must reprogram the unit completely.
3387 <title>Telemetry/RDF/APRS Enable</title>
3389 Enables the radio for transmission during flight. When
3390 disabled, the radio will not transmit anything during flight
3395 <title>Telemetry baud rate</title>
3397 This sets the modulation bit rate for data transmission for
3398 both telemetry and packet link mode. Lower bit
3399 rates will increase range while reducing the amount of data
3400 that can be sent and increasing battery consumption. All
3401 telemetry is done using a rate 1/2 constraint 4 convolution
3402 code, so the actual data transmission rate is 1/2 of the
3403 modulation bit rate specified here.
3407 <title>APRS Interval</title>
3409 How often to transmit GPS information via APRS (in
3410 seconds). When set to zero, APRS transmission is
3411 disabled. This option is available on TeleMetrum v2 and
3412 TeleMega boards. TeleMetrum v1 boards cannot transmit APRS
3413 packets. Note that a single APRS packet takes nearly a full
3414 second to transmit, so enabling this option will prevent
3415 sending any other telemetry during that time.
3419 <title>APRS SSID</title>
3421 Which SSID to report in APRS packets. By default, this is
3422 set to the last digit of the serial number, but can be
3423 configured to any value from 0 to 9.
3427 <title>Callsign</title>
3429 This sets the call sign included in each telemetry packet. Set this
3430 as needed to conform to your local radio regulations.
3434 <title>Maximum Flight Log Size</title>
3436 This sets the space (in kilobytes) allocated for each flight
3437 log. The available space will be divided into chunks of this
3438 size. A smaller value will allow more flights to be stored,
3439 a larger value will record data from longer flights.
3443 <title>Ignitor Firing Mode</title>
3445 This configuration parameter allows the two standard ignitor
3446 channels (Apogee and Main) to be used in different
3451 <term>Dual Deploy</term>
3454 This is the usual mode of operation; the
3455 'apogee' channel is fired at apogee and the 'main'
3456 channel at the height above ground specified by the
3457 'Main Deploy Altitude' during descent.
3462 <term>Redundant Apogee</term>
3465 This fires both channels at
3466 apogee, the 'apogee' channel first followed after a two second
3467 delay by the 'main' channel.
3472 <term>Redundant Main</term>
3475 This fires both channels at the
3476 height above ground specified by the Main Deploy
3477 Altitude setting during descent. The 'apogee'
3478 channel is fired first, followed after a two second
3479 delay by the 'main' channel.
3486 <title>Pad Orientation</title>
3488 Because they include accelerometers, TeleMetrum,
3489 TeleMega and EasyMega are sensitive to the orientation of the board. By
3490 default, they expect the antenna end to point forward. This
3491 parameter allows that default to be changed, permitting the
3492 board to be mounted with the antenna pointing aft instead.
3496 <term>Antenna Up</term>
3499 In this mode, the antenna end of the
3500 flight computer must point forward, in line with the
3501 expected flight path.
3506 <term>Antenna Down</term>
3509 In this mode, the antenna end of the
3510 flight computer must point aft, in line with the
3511 expected flight path.
3518 <title>Beeper Frequency</title>
3520 The beeper on all Altus Metrum flight computers works best
3521 at 4000Hz, however if you have more than one flight computer
3522 in a single airframe, having all of them sound at the same
3523 frequency can be confusing. This parameter lets you adjust
3524 the base beeper frequency value.
3528 <title>Configure Pyro Channels</title>
3532 <imagedata fileref="configure-pyro.png" width="6in" scalefit="1"/>
3537 This opens a separate window to configure the additional
3538 pyro channels available on TeleMega and EasyMega. One column is
3539 presented for each channel. Each row represents a single
3540 parameter, if enabled the parameter must meet the specified
3541 test for the pyro channel to be fired. See the Pyro Channels
3542 section in the System Operation chapter above for a
3543 description of these parameters.
3546 Select conditions and set the related value; the pyro
3547 channel will be activated when <emphasis>all</emphasis> of the
3548 conditions are met. Each pyro channel has a separate set of
3549 configuration values, so you can use different values for
3550 the same condition with different channels.
3553 At the bottom of the window, the 'Pyro Firing Time'
3554 configuration sets the length of time (in seconds) which
3555 each of these pyro channels will fire for.
3558 Once you have selected the appropriate configuration for all
3559 of the necessary pyro channels, you can save the pyro
3560 configuration along with the rest of the flight computer
3561 configuration by pressing the 'Save' button in the main
3562 Configure Flight Computer window.
3567 <title>Configure AltosUI</title>
3571 <imagedata fileref="configure-altosui.png" width="2.4in" scalefit="1"/>
3576 This button presents a dialog so that you can configure the AltosUI global settings.
3579 <title>Voice Settings</title>
3581 AltosUI provides voice announcements during flight so that you
3582 can keep your eyes on the sky and still get information about
3583 the current flight status. However, sometimes you don't want
3590 <para>Turns all voice announcements on and off</para>
3594 <term>Test Voice</term>
3597 Plays a short message allowing you to verify
3598 that the audio system is working and the volume settings
3606 <title>Log Directory</title>
3608 AltosUI logs all telemetry data and saves all TeleMetrum flash
3609 data to this directory. This directory is also used as the
3610 staring point when selecting data files for display or export.
3613 Click on the directory name to bring up a directory choosing
3614 dialog, select a new directory and click 'Select Directory' to
3615 change where AltosUI reads and writes data files.
3619 <title>Callsign</title>
3621 This value is transmitted in each command packet sent from
3622 TeleDongle and received from an altimeter. It is not used in
3623 telemetry mode, as the callsign configured in the altimeter board
3624 is included in all telemetry packets. Configure this
3625 with the AltosUI operators call sign as needed to comply with
3626 your local radio regulations.
3629 Note that to successfully command a flight computer over the radio
3630 (to configure the altimeter, monitor idle, or fire pyro charges),
3631 the callsign configured here must exactly match the callsign
3632 configured in the flight computer. This matching is case
3637 <title>Imperial Units</title>
3639 This switches between metric units (meters) and imperial
3640 units (feet and miles). This affects the display of values
3641 use during flight monitoring, configuration, data graphing
3642 and all of the voice announcements. It does not change the
3643 units used when exporting to CSV files, those are always
3644 produced in metric units.
3648 <title>Font Size</title>
3650 Selects the set of fonts used in the flight monitor
3651 window. Choose between the small, medium and large sets.
3655 <title>Serial Debug</title>
3657 This causes all communication with a connected device to be
3658 dumped to the console from which AltosUI was started. If
3659 you've started it from an icon or menu entry, the output
3660 will simply be discarded. This mode can be useful to debug
3661 various serial communication issues.
3665 <title>Manage Frequencies</title>
3667 This brings up a dialog where you can configure the set of
3668 frequencies shown in the various frequency menus. You can
3669 add as many as you like, or even reconfigure the default
3670 set. Changing this list does not affect the frequency
3671 settings of any devices, it only changes the set of
3672 frequencies shown in the menus.
3677 <title>Configure Groundstation</title>
3681 <imagedata fileref="configure-groundstation.png" width="3.1in" scalefit="1"/>
3686 Select this button and then select a TeleDongle or TeleBT Device from the list provided.
3689 The first few lines of the dialog provide information about the
3690 connected device, including the product name,
3691 software version and hardware serial number. Below that are the
3692 individual configuration entries.
3695 Note that TeleDongle and TeleBT don't save any configuration
3696 data, the settings here are recorded on the local machine in
3697 the Java preferences database. Moving the device to
3698 another machine, or using a different user account on the same
3699 machine will cause settings made here to have no effect.
3702 At the bottom of the dialog, there are three buttons:
3709 This writes any changes to the
3710 local Java preferences file. If you don't
3711 press this button, any changes you make will be lost.
3719 This resets the dialog to the most recently saved values,
3720 erasing any changes you have made.
3728 This closes the dialog. Any unsaved changes will be
3735 The rest of the dialog contains the parameters to be configured.
3738 <title>Frequency</title>
3740 This configures the frequency to use for both telemetry and
3741 packet command mode. Set this before starting any operation
3742 involving packet command mode so that it will use the right
3743 frequency. Telemetry monitoring mode also provides a menu to
3744 change the frequency, and that menu also sets the same Java
3745 preference value used here.
3749 <title>RF Calibration</title>
3751 The radios in every Altus Metrum device are calibrated at the
3752 factory to ensure that they transmit and receive on the
3753 specified frequency. To change a TeleDongle or TeleBT's calibration,
3754 you must reprogram the unit completely, so this entry simply
3755 shows the current value and doesn't allow any changes.
3759 <title>Telemetry Rate</title>
3761 This lets you match the telemetry and packet link rate from
3762 the transmitter. If they don't match, the device won't
3768 <title>Flash Image</title>
3770 This reprograms Altus Metrum devices with new
3771 firmware. TeleMetrum v1.x, TeleDongle, TeleMini and TeleBT are
3772 all reprogrammed by using another similar unit as a
3773 programming dongle (pair programming). TeleMega, EasyMega, TeleMetrum v2
3774 and EasyMini are all programmed directly over their USB ports
3775 (self programming). Please read the directions for flashing
3776 devices in the Updating Device Firmware chapter below.
3780 <title>Fire Igniter</title>
3784 <imagedata fileref="fire-igniter.png" width="1.2in" scalefit="1"/>
3789 This activates the igniter circuits in the flight computer to help
3790 test recovery systems deployment. Because this command can operate
3791 over the Packet Command Link, you can prepare the rocket as
3792 for flight and then test the recovery system without needing
3793 to snake wires inside the air-frame.
3796 Selecting the 'Fire Igniter' button brings up the usual device
3797 selection dialog. Pick the desired device. This brings up another
3798 window which shows the current continuity test status for all
3799 of the pyro channels.
3802 Next, select the desired igniter to fire. This will enable the
3806 Select the 'Arm' button. This enables the 'Fire' button. The
3807 word 'Arm' is replaced by a countdown timer indicating that
3808 you have 10 seconds to press the 'Fire' button or the system
3809 will deactivate, at which point you start over again at
3810 selecting the desired igniter.
3814 <title>Scan Channels</title>
3818 <imagedata fileref="scan-channels.png" width="3.2in" scalefit="1"/>
3823 This listens for telemetry packets on all of the configured
3824 frequencies, displaying information about each device it
3825 receives a packet from. You can select which of the baud rates
3826 and telemetry formats should be tried; by default, it only listens
3827 at 38400 baud with the standard telemetry format used in v1.0 and later
3832 <title>Load Maps</title>
3836 <imagedata fileref="load-maps.png" width="5.2in" scalefit="1"/>
3841 Before heading out to a new launch site, you can use this to
3842 load satellite images in case you don't have internet
3843 connectivity at the site. This loads a fairly large area
3844 around the launch site, which should cover any flight you're likely to make.
3847 There's a drop-down menu of launch sites we know about; if
3848 your favorites aren't there, please let us know the lat/lon
3849 and name of the site. The contents of this list are actually
3850 downloaded from our server at run-time, so as new sites are sent
3851 in, they'll get automatically added to this list.
3852 If the launch site isn't in the list, you can manually enter the lat/lon values
3855 There are four different kinds of maps you can view; you can
3856 select which to download by selecting as many as you like from
3857 the available types:
3863 A combination of satellite imagery and road data. This
3864 is the default view.
3869 <term>Satellite</term>
3872 Just the satellite imagery without any annotation.
3877 <term>Roadmap</term>
3880 Roads, political boundaries and a few geographic features.
3885 <term>Terrain</term>
3888 Contour intervals and shading that show hills and
3896 You can specify the range of zoom levels to download; smaller
3897 numbers show more area with less resolution. The default
3898 level, 0, shows about 3m/pixel. One zoom level change
3899 doubles or halves that number.
3902 The Tile Radius value sets how large an area around the center
3903 point to download. Each tile is 512x512 pixels, and the
3904 'radius' value specifies how many tiles away from the center
3905 will be downloaded. Specify a radius of 0 and you get only the
3906 center tile. A radius of 1 loads a 3x3 grid, centered on the
3910 Clicking the 'Load Map' button will fetch images from Google
3911 Maps; note that Google limits how many images you can fetch at
3912 once, so if you load more than one launch site, you may get
3913 some gray areas in the map which indicate that Google is tired
3914 of sending data to you. Try again later.
3918 <title>Monitor Idle</title>
3920 This brings up a dialog similar to the Monitor Flight UI,
3921 except it works with the altimeter in “idle” mode by sending
3922 query commands to discover the current state rather than
3923 listening for telemetry packets. Because this uses command
3924 mode, it needs to have the TeleDongle and flight computer
3925 callsigns match exactly. If you can receive telemetry, but
3926 cannot manage to run Monitor Idle, then it's very likely that
3927 your callsigns are different in some way.
3932 <title>AltosDroid</title>
3934 AltosDroid provides the same flight monitoring capabilities as
3935 AltosUI, but runs on Android devices and is designed to connect
3936 to a TeleBT receiver over Bluetooth™. AltosDroid monitors
3937 telemetry data, logging it to internal storage in the Android
3938 device, and presents that data in a UI the same way the 'Monitor
3939 Flight' window does in AltosUI.
3942 This manual will explain how to configure AltosDroid, connect
3943 to TeleBT, operate the flight monitoring interface and describe
3944 what the displayed data means.
3947 <title>Installing AltosDroid</title>
3949 AltosDroid is available from the Google Play store. To install
3950 it on your Android device, open the Google Play Store
3951 application and search for “altosdroid”. Make sure you don't
3952 have a space between “altos” and “droid” or you probably won't
3953 find what you want. That should bring you to the right page
3954 from which you can download and install the application.
3958 <title>Connecting to TeleBT</title>
3960 Press the Android 'Menu' button or soft-key to see the
3961 configuration options available. Select the 'Connect a device'
3962 option and then the 'Scan for devices' entry at the bottom to
3963 look for your TeleBT device. Select your device, and when it
3964 asks for the code, enter '1234'.
3967 Subsequent connections will not require you to enter that
3968 code, and your 'paired' device will appear in the list without
3973 <title>Configuring AltosDroid</title>
3975 The only configuration option available for AltosDroid is
3976 which frequency to listen on. Press the Android 'Menu' button
3977 or soft-key and pick the 'Select radio frequency' entry. That
3978 brings up a menu of pre-set radio frequencies; pick the one
3979 which matches your altimeter.
3983 <title>AltosDroid Flight Monitoring</title>
3985 AltosDroid is designed to mimic the AltosUI flight monitoring
3986 display, providing separate tabs for each stage of your rocket
3987 flight along with a tab containing a map of the local area
3988 with icons marking the current location of the altimeter and
3994 The 'Launch Pad' tab shows information used to decide when the
3995 rocket is ready for flight. The first elements include red/green
3996 indicators, if any of these is red, you'll want to evaluate
3997 whether the rocket is ready to launch:
4000 <term>Battery Voltage</term>
4003 This indicates whether the Li-Po battery
4004 powering the TeleMetrum has sufficient charge to last for
4005 the duration of the flight. A value of more than
4006 3.8V is required for a 'GO' status.
4011 <term>Apogee Igniter Voltage</term>
4014 This indicates whether the apogee
4015 igniter has continuity. If the igniter has a low
4016 resistance, then the voltage measured here will be close
4017 to the Li-Po battery voltage. A value greater than 3.2V is
4018 required for a 'GO' status.
4023 <term>Main Igniter Voltage</term>
4026 This indicates whether the main
4027 igniter has continuity. If the igniter has a low
4028 resistance, then the voltage measured here will be close
4029 to the Li-Po battery voltage. A value greater than 3.2V is
4030 required for a 'GO' status.
4035 <term>On-board Data Logging</term>
4038 This indicates whether there is
4039 space remaining on-board to store flight data for the
4040 upcoming flight. If you've downloaded data, but failed
4041 to erase flights, there may not be any space
4042 left. TeleMetrum can store multiple flights, depending
4043 on the configured maximum flight log size. TeleMini
4044 stores only a single flight, so it will need to be
4045 downloaded and erased after each flight to capture
4046 data. This only affects on-board flight logging; the
4047 altimeter will still transmit telemetry and fire
4048 ejection charges at the proper times.
4053 <term>GPS Locked</term>
4056 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
4057 currently able to compute position information. GPS requires
4058 at least 4 satellites to compute an accurate position.
4063 <term>GPS Ready</term>
4066 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
4067 10 consecutive positions without losing lock. This ensures
4068 that the GPS receiver has reliable reception from the
4076 The Launchpad tab also shows the computed launch pad position
4077 and altitude, averaging many reported positions to improve the
4078 accuracy of the fix.
4083 <title>Downloading Flight Logs</title>
4085 AltosDroid always saves every bit of telemetry data it
4086 receives. To download that to a computer for use with AltosUI,
4087 simply remove the SD card from your Android device, or connect
4088 your device to your computer's USB port and browse the files
4089 on that device. You will find '.telem' files in the TeleMetrum
4090 directory that will work with AltosUI directly.
4095 <title>Using Altus Metrum Products</title>
4097 <title>Being Legal</title>
4099 First off, in the US, you need an <ulink url="http://www.altusmetrum.org/Radio/">amateur radio license</ulink> or
4100 other authorization to legally operate the radio transmitters that are part
4105 <title>In the Rocket</title>
4107 In the rocket itself, you just need a flight computer and
4108 a single-cell, 3.7 volt nominal Li-Po rechargeable battery. An
4109 850mAh battery weighs less than a 9V alkaline battery, and will
4110 run a TeleMetrum, TeleMega or EasyMega for hours.
4111 A 110mAh battery weighs less than a triple A battery and is a good
4112 choice for use with TeleMini or EasyMini.
4115 By default, we ship TeleMini, TeleMetrum and TeleMega flight computers with a simple wire antenna.
4116 If your electronics bay or the air-frame it resides within is made
4117 of carbon fiber, which is opaque to RF signals, you may prefer to
4118 install an SMA connector so that you can run a coaxial cable to an
4119 antenna mounted elsewhere in the rocket. However, note that the
4120 GPS antenna is fixed on all current products, so you really want
4121 to install the flight computer in a bay made of RF-transparent
4122 materials if at all possible.
4126 <title>On the Ground</title>
4128 To receive the data stream from the rocket, you need an antenna and short
4129 feed-line connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. If possible, use an SMA to BNC
4130 adapter instead of feedline between the antenna feedpoint and
4131 TeleDongle, as this will give you the best performance. The
4132 TeleDongle in turn plugs directly into the USB port on a notebook
4133 computer. Because TeleDongle looks like a simple serial port, your computer
4134 does not require special device drivers... just plug it in.
4137 The GUI tool, AltosUI, is written in Java and runs across
4138 Linux, Mac OS and Windows. There's also a suite of C tools
4139 for Linux which can perform most of the same tasks.
4142 Alternatively, a TeleBT attached with an SMA to BNC adapter at the
4143 feed point of a hand-held yagi used in conjunction with an Android
4144 device running AltosDroid makes an outstanding ground station.
4147 After the flight, you can use the radio link to extract the more detailed data
4148 logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
4149 TeleMetrum board directly. Pulling out the data without having to open up
4150 the rocket is pretty cool! A USB cable is also how you charge the Li-Po
4151 battery, so you'll want one of those anyway... the same cable used by lots
4152 of digital cameras and other modern electronic stuff will work fine.
4155 If your rocket lands out of sight, you may enjoy having a hand-held
4156 GPS receiver, so that you can put in a way-point for the last
4157 reported rocket position before touch-down. This makes looking for
4158 your rocket a lot like Geo-Caching... just go to the way-point and
4159 look around starting from there. AltosDroid on an Android device
4160 with GPS receiver works great for this, too!
4163 You may also enjoy having a ham radio “HT” that covers the 70cm band... you
4164 can use that with your antenna to direction-find the rocket on the ground
4165 the same way you can use a Walston or Beeline tracker. This can be handy
4166 if the rocket is hiding in sage brush or a tree, or if the last GPS position
4167 doesn't get you close enough because the rocket dropped into a canyon, or
4168 the wind is blowing it across a dry lake bed, or something like that... Keith
4169 currently uses a Yaesu FT1D, Bdale has a Yaesu VX-7R, which
4170 is a nicer radio in most ways but doesn't support APRS.
4173 So, to recap, on the ground the hardware you'll need includes:
4174 <orderedlist inheritnum='inherit' numeration='arabic'>
4177 an antenna and feed-line or adapter
4192 optionally, a hand-held GPS receiver
4197 optionally, an HT or receiver covering 435 MHz
4203 The best hand-held commercial directional antennas we've found for radio
4204 direction finding rockets are from
4205 <ulink url="http://www.arrowantennas.com/" >
4208 The 440-3 and 440-5 are both good choices for finding a
4209 TeleMetrum- or TeleMini- equipped rocket when used with a suitable
4210 70cm HT. TeleDongle and an SMA to BNC adapter fit perfectly
4211 between the driven element and reflector of Arrow antennas.
4215 <title>Data Analysis</title>
4217 Our software makes it easy to log the data from each flight, both the
4218 telemetry received during the flight itself, and the more
4219 complete data log recorded in the flash memory on the altimeter
4220 board. Once this data is on your computer, our post-flight tools make it
4221 easy to quickly get to the numbers everyone wants, like apogee altitude,
4222 max acceleration, and max velocity. You can also generate and view a
4223 standard set of plots showing the altitude, acceleration, and
4224 velocity of the rocket during flight. And you can even export a TeleMetrum data file
4225 usable with Google Maps and Google Earth for visualizing the flight path
4226 in two or three dimensions!
4229 Our ultimate goal is to emit a set of files for each flight that can be
4230 published as a web page per flight, or just viewed on your local disk with
4235 <title>Future Plans</title>
4237 We have designed and prototyped several “companion boards” that
4238 can attach to the companion connector on TeleMetrum,
4239 TeleMega and EasyMega
4240 flight computers to collect more data, provide more pyro channels,
4241 and so forth. We do not yet know if or when any of these boards
4242 will be produced in enough quantity to sell. If you have specific
4243 interests for data collection or control of events in your rockets
4244 beyond the capabilities of our existing productions, please let
4248 Because all of our work is open, both the hardware designs and the
4249 software, if you have some great idea for an addition to the current
4250 Altus Metrum family, feel free to dive in and help! Or let us know
4251 what you'd like to see that we aren't already working on, and maybe
4252 we'll get excited about it too...
4256 <ulink url="http://altusmetrum.org/">web site</ulink> for more news
4257 and information as our family of products evolves!
4262 <title>Altimeter Installation Recommendations</title>
4264 Building high-power rockets that fly safely is hard enough. Mix
4265 in some sophisticated electronics and a bunch of radio energy
4266 and some creativity and/or compromise may be required. This chapter
4267 contains some suggestions about how to install Altus Metrum
4268 products into a rocket air-frame, including how to safely and
4269 reliably mix a variety of electronics into the same air-frame.
4272 <title>Mounting the Altimeter</title>
4274 The first consideration is to ensure that the altimeter is
4275 securely fastened to the air-frame. For most of our products, we
4276 prefer nylon standoffs and nylon screws; they're good to at least 50G
4277 and cannot cause any electrical issues on the board. Metal screws
4278 and standoffs are fine, too, just be careful to avoid electrical
4279 shorts! For TeleMini v1.0, we usually cut small pieces of 1/16 inch
4281 under the screw holes, and then take 2x56 nylon screws and
4282 screw them through the TeleMini mounting holes, through the
4283 balsa and into the underlying material.
4285 <orderedlist inheritnum='inherit' numeration='arabic'>
4288 Make sure accelerometer-equipped products like TeleMetrum,
4289 TeleMega and EasyMega are aligned precisely along the axis of
4290 acceleration so that the accelerometer can accurately
4291 capture data during the flight.
4296 Watch for any metal touching components on the
4297 board. Shorting out connections on the bottom of the board
4298 can cause the altimeter to fail during flight.
4304 <title>Dealing with the Antenna</title>
4306 The antenna supplied is just a piece of solid, insulated,
4307 wire. If it gets damaged or broken, it can be easily
4308 replaced. It should be kept straight and not cut; bending or
4309 cutting it will change the resonant frequency and/or
4310 impedance, making it a less efficient radiator and thus
4311 reducing the range of the telemetry signal.
4314 Keeping metal away from the antenna will provide better range
4315 and a more even radiation pattern. In most rockets, it's not
4316 entirely possible to isolate the antenna from metal
4317 components; there are often bolts, all-thread and wires from other
4318 electronics to contend with. Just be aware that the more stuff
4319 like this around the antenna, the lower the range.
4322 Make sure the antenna is not inside a tube made or covered
4323 with conducting material. Carbon fiber is the most common
4324 culprit here -- CF is a good conductor and will effectively
4325 shield the antenna, dramatically reducing signal strength and
4326 range. Metallic flake paint is another effective shielding
4327 material which should be avoided around any antennas.
4330 If the ebay is large enough, it can be convenient to simply
4331 mount the altimeter at one end and stretch the antenna out
4332 inside. Taping the antenna to the sled can keep it straight
4333 under acceleration. If there are metal rods, keep the
4334 antenna as far away as possible.
4337 For a shorter ebay, it's quite practical to have the antenna
4338 run through a bulkhead and into an adjacent bay. Drill a small
4339 hole in the bulkhead, pass the antenna wire through it and
4340 then seal it up with glue or clay. We've also used acrylic
4341 tubing to create a cavity for the antenna wire. This works a
4342 bit better in that the antenna is known to stay straight and
4343 not get folded by recovery components in the bay. Angle the
4344 tubing towards the side wall of the rocket and it ends up
4345 consuming very little space.
4348 If you need to place the UHF antenna at a distance from the
4349 altimeter, you can replace the antenna with an edge-mounted
4350 SMA connector, and then run 50Ω coax from the board to the
4351 antenna. Building a remote antenna is beyond the scope of this
4356 <title>Preserving GPS Reception</title>
4358 The GPS antenna and receiver used in TeleMetrum and TeleMega is
4359 highly sensitive and normally have no trouble tracking enough
4360 satellites to provide accurate position information for
4361 recovering the rocket. However, there are many ways the GPS signal
4362 can end up attenuated, negatively affecting GPS performance.
4363 <orderedlist inheritnum='inherit' numeration='arabic'>
4366 Conductive tubing or coatings. Carbon fiber and metal
4367 tubing, or metallic paint will all dramatically attenuate the
4368 GPS signal. We've never heard of anyone successfully
4369 receiving GPS from inside these materials.
4374 Metal components near the GPS patch antenna. These will
4375 de-tune the patch antenna, changing the resonant frequency
4376 away from the L1 carrier and reduce the effectiveness of the
4377 antenna. You can place as much stuff as you like beneath the
4378 antenna as that's covered with a ground plane. But, keep
4379 wires and metal out from above the patch antenna.
4386 <title>Radio Frequency Interference</title>
4388 Any altimeter will generate RFI; the digital circuits use
4389 high-frequency clocks that spray radio interference across a
4390 wide band. Altus Metrum altimeters generate intentional radio
4391 signals as well, increasing the amount of RF energy around the board.
4394 Rocketry altimeters also use precise sensors measuring air
4395 pressure and acceleration. Tiny changes in voltage can cause
4396 these sensor readings to vary by a huge amount. When the
4397 sensors start mis-reporting data, the altimeter can either
4398 fire the igniters at the wrong time, or not fire them at all.
4401 Voltages are induced when radio frequency energy is
4402 transmitted from one circuit to another. Here are things that
4403 influence the induced voltage and current:
4408 Keep wires from different circuits apart. Moving circuits
4409 further apart will reduce RFI.
4414 Avoid parallel wires from different circuits. The longer two
4415 wires run parallel to one another, the larger the amount of
4416 transferred energy. Cross wires at right angles to reduce
4422 Twist wires from the same circuits. Two wires the same
4423 distance from the transmitter will get the same amount of
4424 induced energy which will then cancel out. Any time you have
4425 a wire pair running together, twist the pair together to
4426 even out distances and reduce RFI. For altimeters, this
4427 includes battery leads, switch hookups and igniter
4433 Avoid resonant lengths. Know what frequencies are present
4434 in the environment and avoid having wire lengths near a
4435 natural resonant length. Altus Metrum products transmit on the
4436 70cm amateur band, so you should avoid lengths that are a
4437 simple ratio of that length; essentially any multiple of ¼
4438 of the wavelength (17.5cm).
4444 <title>The Barometric Sensor</title>
4446 Altusmetrum altimeters measure altitude with a barometric
4447 sensor, essentially measuring the amount of air above the
4448 rocket to figure out how high it is. A large number of
4449 measurements are taken as the altimeter initializes itself to
4450 figure out the pad altitude. Subsequent measurements are then
4451 used to compute the height above the pad.
4454 To accurately measure atmospheric pressure, the ebay
4455 containing the altimeter must be vented outside the
4456 air-frame. The vent must be placed in a region of linear
4457 airflow, have smooth edges, and away from areas of increasing or
4458 decreasing pressure.
4461 All barometric sensors are quite sensitive to chemical damage from
4462 the products of APCP or BP combustion, so make sure the ebay is
4463 carefully sealed from any compartment which contains ejection
4468 <title>Ground Testing</title>
4470 The most important aspect of any installation is careful
4471 ground testing. Bringing an air-frame up to the LCO table which
4472 hasn't been ground tested can lead to delays or ejection
4473 charges firing on the pad, or, even worse, a recovery system
4477 Do a 'full systems' test that includes wiring up all igniters
4478 without any BP and turning on all of the electronics in flight
4479 mode. This will catch any mistakes in wiring and any residual
4480 RFI issues that might accidentally fire igniters at the wrong
4481 time. Let the air-frame sit for several minutes, checking for
4482 adequate telemetry signal strength and GPS lock. If any igniters
4483 fire unexpectedly, find and resolve the issue before loading any
4487 Ground test the ejection charges. Prepare the rocket for
4488 flight, loading ejection charges and igniters. Completely
4489 assemble the air-frame and then use the 'Fire Igniters'
4490 interface through a TeleDongle to command each charge to
4491 fire. Make sure the charge is sufficient to robustly separate
4492 the air-frame and deploy the recovery system.
4497 <title>Updating Device Firmware</title>
4499 TeleMega, TeleMetrum v2, EasyMega and EasyMini are all programmed directly
4500 over their USB connectors (self programming). TeleMetrum v1, TeleMini and
4501 TeleDongle are all programmed by using another device as a
4502 programmer (pair programming). It's important to recognize which
4503 kind of devices you have before trying to reprogram them.
4506 You may wish to begin by ensuring you have current firmware images.
4507 These are distributed as part of the AltOS software bundle that
4508 also includes the AltosUI ground station program. Newer ground
4509 station versions typically work fine with older firmware versions,
4510 so you don't need to update your devices just to try out new
4511 software features. You can always download the most recent
4512 version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
4515 If you need to update the firmware on a TeleDongle, we recommend
4516 updating the altimeter first, before updating TeleDongle. However,
4517 note that TeleDongle rarely need to be updated. Any firmware version
4518 1.0.1 or later will work, version 1.2.1 may have improved receiver
4519 performance slightly.
4522 Self-programmable devices (TeleMega, TeleMetrum v2, EasyMega and EasyMini)
4523 are reprogrammed by connecting them to your computer over USB
4527 Updating TeleMega, TeleMetrum v2, EasyMega or EasyMini Firmware
4529 <orderedlist inheritnum='inherit' numeration='arabic'>
4532 Attach a battery and power switch to the target
4533 device. Power up the device.
4538 Using a Micro USB cable, connect the target device to your
4539 computer's USB socket.
4544 Run AltosUI, and select 'Flash Image' from the File menu.
4549 Select the target device in the Device Selection dialog.
4554 Select the image you want to flash to the device, which
4555 should have a name in the form
4556 <product>-v<product-version>-<software-version>.ihx, such
4557 as TeleMega-v1.0-1.3.0.ihx.
4562 Make sure the configuration parameters are reasonable
4563 looking. If the serial number and/or RF configuration
4564 values aren't right, you'll need to change them.
4569 Hit the 'OK' button and the software should proceed to flash
4570 the device with new firmware, showing a progress bar.
4575 Verify that the device is working by using the 'Configure
4576 Altimeter' item to check over the configuration.
4581 <title>Recovering From Self-Flashing Failure</title>
4583 If the firmware loading fails, it can leave the device
4584 unable to boot. Not to worry, you can force the device to
4585 start the boot loader instead, which will let you try to
4586 flash the device again.
4589 On each device, connecting two pins from one of the exposed
4590 connectors will force the boot loader to start, even if the
4591 regular operating system has been corrupted in some way.
4595 <term>TeleMega</term>
4598 Connect pin 6 and pin 1 of the companion connector. Pin 1
4599 can be identified by the square pad around it, and then
4600 the pins could sequentially across the board. Be very
4601 careful to <emphasis>not</emphasis> short pin 8 to
4602 anything as that is connected directly to the battery. Pin
4603 7 carries 3.3V and the board will crash if that is
4604 connected to pin 1, but shouldn't damage the board.
4609 <term>EasyMega</term>
4612 Connect pin 6 and pin 1 of the companion connector. Pin 1
4613 can be identified by the square pad around it, and then
4614 the pins could sequentially across the board. Be very
4615 careful to <emphasis>not</emphasis> short pin 8 to
4616 anything as that is connected directly to the battery. Pin
4617 7 carries 3.3V and the board will crash if that is
4618 connected to pin 1, but shouldn't damage the board.
4623 <term>TeleMetrum v2</term>
4626 Connect pin 6 and pin 1 of the companion connector. Pin 1
4627 can be identified by the square pad around it, and then
4628 the pins could sequentially across the board. Be very
4629 careful to <emphasis>not</emphasis> short pin 8 to
4630 anything as that is connected directly to the battery. Pin
4631 7 carries 3.3V and the board will crash if that is
4632 connected to pin 1, but shouldn't damage the board.
4637 <term>EasyMini</term>
4640 Connect pin 6 and pin 1 of the debug connector, which is
4641 the six holes next to the beeper. Pin 1 can be identified
4642 by the square pad around it, and then the pins could
4643 sequentially across the board, making Pin 6 the one on the
4644 other end of the row.
4650 Once you've located the right pins:
4652 <orderedlist inheritnum='inherit' numeration='arabic'>
4655 Turn the altimeter power off.
4665 Connect the indicated terminals together with a short
4666 piece of wire. Take care not to accidentally connect
4677 Turn the board power on.
4682 The board should now be visible over USB as 'AltosFlash'
4683 and be ready to receive firmware.
4688 Once the board has been powered up, you can remove the
4696 <title>Pair Programming</title>
4698 The big concept to understand is that you have to use a
4699 TeleMega, TeleMetrum or TeleDongle as a programmer to update a
4700 pair programmed device. Due to limited memory resources in the
4701 cc1111, we don't support programming directly over USB for these
4706 <title>Updating TeleMetrum v1.x Firmware</title>
4707 <orderedlist inheritnum='inherit' numeration='arabic'>
4710 Find the 'programming cable' that you got as part of the starter
4711 kit, that has a red 8-pin MicroMaTch connector on one end and a
4712 red 4-pin MicroMaTch connector on the other end.
4717 Take the 2 screws out of the TeleDongle case to get access
4718 to the circuit board.
4723 Plug the 8-pin end of the programming cable to the
4724 matching connector on the TeleDongle, and the 4-pin end to the
4725 matching connector on the TeleMetrum.
4726 Note that each MicroMaTch connector has an alignment pin that
4727 goes through a hole in the PC board when you have the cable
4733 Attach a battery to the TeleMetrum board.
4738 Plug the TeleDongle into your computer's USB port, and power
4744 Run AltosUI, and select 'Flash Image' from the File menu.
4749 Pick the TeleDongle device from the list, identifying it as the
4755 Select the image you want put on the TeleMetrum, which should have a
4756 name in the form telemetrum-v1.2-1.0.0.ihx. It should be visible
4757 in the default directory, if not you may have to poke around
4758 your system to find it.
4763 Make sure the configuration parameters are reasonable
4764 looking. If the serial number and/or RF configuration
4765 values aren't right, you'll need to change them.
4770 Hit the 'OK' button and the software should proceed to flash
4771 the TeleMetrum with new firmware, showing a progress bar.
4776 Confirm that the TeleMetrum board seems to have updated OK, which you
4777 can do by plugging in to it over USB and using a terminal program
4778 to connect to the board and issue the 'v' command to check
4784 If something goes wrong, give it another try.
4790 <title>Updating TeleMini Firmware</title>
4791 <orderedlist inheritnum='inherit' numeration='arabic'>
4794 You'll need a special 'programming cable' to reprogram the
4795 TeleMini. You can make your own using an 8-pin MicroMaTch
4796 connector on one end and a set of four pins on the other.
4801 Take the 2 screws out of the TeleDongle case to get access
4802 to the circuit board.
4807 Plug the 8-pin end of the programming cable to the matching
4808 connector on the TeleDongle, and the 4-pins into the holes
4809 in the TeleMini circuit board. Note that the MicroMaTch
4810 connector has an alignment pin that goes through a hole in
4811 the PC board when you have the cable oriented correctly, and
4812 that pin 1 on the TeleMini board is marked with a square pad
4813 while the other pins have round pads.
4818 Attach a battery to the TeleMini board.
4823 Plug the TeleDongle into your computer's USB port, and power
4829 Run AltosUI, and select 'Flash Image' from the File menu.
4834 Pick the TeleDongle device from the list, identifying it as the
4840 Select the image you want put on the TeleMini, which should have a
4841 name in the form telemini-v1.0-1.0.0.ihx. It should be visible
4842 in the default directory, if not you may have to poke around
4843 your system to find it.
4848 Make sure the configuration parameters are reasonable
4849 looking. If the serial number and/or RF configuration
4850 values aren't right, you'll need to change them.
4855 Hit the 'OK' button and the software should proceed to flash
4856 the TeleMini with new firmware, showing a progress bar.
4861 Confirm that the TeleMini board seems to have updated OK, which you
4862 can do by configuring it over the radio link through the TeleDongle, or
4863 letting it come up in “flight” mode and listening for telemetry.
4868 If something goes wrong, give it another try.
4874 <title>Updating TeleDongle Firmware</title>
4876 Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
4877 firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
4879 <orderedlist inheritnum='inherit' numeration='arabic'>
4882 Find the 'programming cable' that you got as part of the starter
4883 kit, that has a red 8-pin MicroMaTch connector on one end and a
4884 red 4-pin MicroMaTch connector on the other end.
4889 Find the USB cable that you got as part of the starter kit, and
4890 plug the “mini” end in to the mating connector on TeleMetrum or TeleDongle.
4895 Take the 2 screws out of the TeleDongle case to get access
4896 to the circuit board.
4901 Plug the 8-pin end of the programming cable to the
4902 matching connector on the programmer, and the 4-pin end to the
4903 matching connector on the TeleDongle.
4904 Note that each MicroMaTch connector has an alignment pin that
4905 goes through a hole in the PC board when you have the cable
4911 Attach a battery to the TeleMetrum board if you're using one.
4916 Plug both the programmer and the TeleDongle into your computer's USB
4917 ports, and power up the programmer.
4922 Run AltosUI, and select 'Flash Image' from the File menu.
4927 Pick the programmer device from the list, identifying it as the
4933 Select the image you want put on the TeleDongle, which should have a
4934 name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
4935 in the default directory, if not you may have to poke around
4936 your system to find it.
4941 Make sure the configuration parameters are reasonable
4942 looking. If the serial number and/or RF configuration
4943 values aren't right, you'll need to change them. The TeleDongle
4944 serial number is on the “bottom” of the circuit board, and can
4945 usually be read through the translucent blue plastic case without
4946 needing to remove the board from the case.
4951 Hit the 'OK' button and the software should proceed to flash
4952 the TeleDongle with new firmware, showing a progress bar.
4957 Confirm that the TeleDongle board seems to have updated OK, which you
4958 can do by plugging in to it over USB and using a terminal program
4959 to connect to the board and issue the 'v' command to check
4960 the version, etc. Once you're happy, remove the programming cable
4961 and put the cover back on the TeleDongle.
4966 If something goes wrong, give it another try.
4971 Be careful removing the programming cable from the locking 8-pin
4972 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
4973 screwdriver or knife blade to gently pry the locking ears out
4974 slightly to extract the connector. We used a locking connector on
4975 TeleMetrum to help ensure that the cabling to companion boards
4976 used in a rocket don't ever come loose accidentally in flight.
4981 <title>Hardware Specifications</title>
4984 TeleMega Specifications
4989 Recording altimeter for model rocketry.
4994 Supports dual deployment and four auxiliary pyro channels
4995 (a total of 6 events).
5000 70cm 40mW ham-band transceiver for telemetry down-link.
5005 Barometric pressure sensor good to 100k feet MSL.
5010 1-axis high-g accelerometer for motor characterization, capable of
5016 9-axis IMU including integrated 3-axis accelerometer,
5017 3-axis gyroscope and 3-axis magnetometer.
5022 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
5027 On-board 8 Megabyte non-volatile memory for flight data storage.
5032 USB interface for battery charging, configuration, and data recovery.
5037 Fully integrated support for Li-Po rechargeable batteries.
5042 Can use either main system Li-Po or optional separate pyro battery
5048 3.25 x 1.25 inch board designed to fit inside 38mm air-frame coupler tube.
5055 EasyMega Specifications
5060 Recording altimeter for model rocketry.
5065 Supports dual deployment and four auxiliary pyro channels
5066 (a total of 6 events).
5071 Barometric pressure sensor good to 100k feet MSL.
5076 1-axis high-g accelerometer for motor characterization, capable of
5082 9-axis IMU including integrated 3-axis accelerometer,
5083 3-axis gyroscope and 3-axis magnetometer.
5088 On-board 8 Megabyte non-volatile memory for flight data storage.
5093 USB interface for battery charging, configuration, and data recovery.
5098 Fully integrated support for Li-Po rechargeable batteries.
5103 Can use either main system Li-Po or optional separate pyro battery
5109 1.25 x 1.25 inch board designed to fit inside 38mm air-frame coupler tube.
5116 TeleMetrum v2 Specifications
5121 Recording altimeter for model rocketry.
5126 Supports dual deployment (can fire 2 ejection charges).
5131 70cm, 40mW ham-band transceiver for telemetry down-link.
5136 Barometric pressure sensor good to 100k feet MSL.
5141 1-axis high-g accelerometer for motor characterization, capable of
5147 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
5152 On-board 8 Megabyte non-volatile memory for flight data storage.
5157 USB interface for battery charging, configuration, and data recovery.
5162 Fully integrated support for Li-Po rechargeable batteries.
5167 Uses Li-Po to fire e-matches, can be modified to support
5168 optional separate pyro battery if needed.
5173 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
5179 <title>TeleMetrum v1 Specifications</title>
5183 Recording altimeter for model rocketry.
5188 Supports dual deployment (can fire 2 ejection charges).
5193 70cm, 10mW ham-band transceiver for telemetry down-link.
5198 Barometric pressure sensor good to 45k feet MSL.
5203 1-axis high-g accelerometer for motor characterization, capable of
5204 +/- 50g using default part.
5209 On-board, integrated GPS receiver with 5Hz update rate capability.
5214 On-board 1 megabyte non-volatile memory for flight data storage.
5219 USB interface for battery charging, configuration, and data recovery.
5224 Fully integrated support for Li-Po rechargeable batteries.
5229 Uses Li-Po to fire e-matches, can be modified to support
5230 optional separate pyro battery if needed.
5235 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
5242 TeleMini v2.0 Specifications
5247 Recording altimeter for model rocketry.
5252 Supports dual deployment (can fire 2 ejection charges).
5257 70cm, 10mW ham-band transceiver for telemetry down-link.
5262 Barometric pressure sensor good to 100k feet MSL.
5267 On-board 1 megabyte non-volatile memory for flight data storage.
5272 USB interface for configuration, and data recovery.
5277 Support for Li-Po rechargeable batteries (using an
5278 external charger), or any 3.7-15V external battery.
5283 Uses Li-Po to fire e-matches, can be modified to support
5284 optional separate pyro battery if needed.
5289 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
5296 TeleMini v1.0 Specifications
5301 Recording altimeter for model rocketry.
5306 Supports dual deployment (can fire 2 ejection charges).
5311 70cm, 10mW ham-band transceiver for telemetry down-link.
5316 Barometric pressure sensor good to 45k feet MSL.
5321 On-board 5 kilobyte non-volatile memory for flight data storage.
5326 RF interface for configuration, and data recovery.
5331 Support for Li-Po rechargeable batteries, using an external charger.
5336 Uses Li-Po to fire e-matches, can be modified to support
5337 optional separate pyro battery if needed.
5342 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube.
5349 EasyMini Specifications
5354 Recording altimeter for model rocketry.
5359 Supports dual deployment (can fire 2 ejection charges).
5364 Barometric pressure sensor good to 100k feet MSL.
5369 On-board 1 megabyte non-volatile memory for flight data storage.
5374 USB interface for configuration, and data recovery.
5379 Support for Li-Po rechargeable batteries (using an
5380 external charger), or any 3.7-15V external battery.
5385 Uses Li-Po to fire e-matches, can be modified to support
5386 optional separate pyro battery if needed.
5391 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
5400 <emphasis>TeleMetrum seems to shut off when disconnected from the
5401 computer.</emphasis> <?linebreak?>
5402 Make sure the battery is adequately charged. Remember the
5403 unit will pull more power than the USB port can deliver before the
5404 GPS enters “locked” mode. The battery charges best when TeleMetrum
5408 <emphasis>It's impossible to stop the TeleDongle when it's in “p” mode, I have
5409 to unplug the USB cable? </emphasis><?linebreak?>
5410 Make sure you have tried to “escape out” of
5411 this mode. If this doesn't work the reboot procedure for the
5412 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
5413 outgoing buffer IF your “escape out” ('~~') does not work.
5414 At this point using either 'ao-view' (or possibly
5415 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
5419 <emphasis>The amber LED (on the TeleMetrum) lights up when both
5420 battery and USB are connected. Does this mean it's charging?
5421 </emphasis><?linebreak?>
5422 Yes, the yellow LED indicates the charging at the 'regular' rate.
5423 If the led is out but the unit is still plugged into a USB port,
5424 then the battery is being charged at a 'trickle' rate.
5427 <emphasis>There are no “dit-dah-dah-dit” sound or lights like the manual
5428 mentions?</emphasis><?linebreak?>
5429 That's the “pad” mode. Weak batteries might be the problem.
5430 It is also possible that the flight computer is horizontal and the
5432 is instead a “dit-dit” meaning 'idle'. For TeleMini, it's possible that
5433 it received a command packet which would have left it in “pad” mode.
5436 <emphasis>How do I save flight data?</emphasis><?linebreak?>
5437 Live telemetry is written to file(s) whenever AltosUI is connected
5438 to the TeleDongle. The file area defaults to ~/TeleMetrum
5439 but is easily changed using the menus in AltosUI. The files that
5440 are written end in '.telem'. The after-flight
5441 data-dumped files will end in .eeprom and represent continuous data
5442 unlike the .telem files that are subject to losses
5443 along the RF data path.
5444 See the above instructions on what and how to save the eeprom stored
5445 data after physically retrieving your altimeter. Make sure to save
5446 the on-board data after each flight; while the TeleMetrum can store
5447 multiple flights, you never know when you'll lose the altimeter...
5451 <title>Notes for Older Software</title>
5454 Before AltosUI was written, using Altus Metrum devices required
5455 some finesse with the Linux command line. There was a limited
5456 GUI tool, ao-view, which provided functionality similar to the
5457 Monitor Flight window in AltosUI, but everything else was a
5458 fairly 80's experience. This appendix includes documentation for
5459 using that software.
5463 Both TeleMetrum and TeleDongle can be directly communicated
5464 with using USB ports. The first thing you should try after getting
5465 both units plugged into to your computer's USB port(s) is to run
5466 'ao-list' from a terminal-window to see what port-device-name each
5467 device has been assigned by the operating system.
5468 You will need this information to access the devices via their
5469 respective on-board firmware and data using other command line
5470 programs in the AltOS software suite.
5473 TeleMini can be communicated with through a TeleDongle device
5474 over the radio link. When first booted, TeleMini listens for a
5475 TeleDongle device and if it receives a packet, it goes into
5476 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be
5477 launched. The easiest way to get it talking is to start the
5478 communication link on the TeleDongle and the power up the
5482 To access the device's firmware for configuration you need a terminal
5483 program such as you would use to talk to a modem. The software
5484 authors prefer using the program 'cu' which comes from the UUCP package
5485 on most Unix-like systems such as Linux. An example command line for
5486 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
5487 indicated from running the
5488 ao-list program. Another reasonable terminal program for Linux is
5489 'cutecom'. The default 'escape'
5490 character used by CU (i.e. the character you use to
5491 issue commands to cu itself instead of sending the command as input
5492 to the connected device) is a '~'. You will need this for use in
5493 only two different ways during normal operations. First is to exit
5494 the program by sending a '~.' which is called a 'escape-disconnect'
5495 and allows you to close-out from 'cu'. The
5496 second use will be outlined later.
5499 All of the Altus Metrum devices share the concept of a two level
5500 command set in their firmware.
5501 The first layer has several single letter commands. Once
5502 you are using 'cu' (or 'cutecom') sending (typing) a '?'
5503 returns a full list of these
5504 commands. The second level are configuration sub-commands accessed
5505 using the 'c' command, for
5506 instance typing 'c?' will give you this second level of commands
5507 (all of which require the
5508 letter 'c' to access). Please note that most configuration options
5509 are stored only in Flash memory; TeleDongle doesn't provide any storage
5510 for these options and so they'll all be lost when you unplug it.
5513 Try setting these configuration ('c' or second level menu) values. A good
5514 place to start is by setting your call sign. By default, the boards
5515 use 'N0CALL' which is cute, but not exactly legal!
5516 Spend a few minutes getting comfortable with the units, their
5517 firmware, and 'cu' (or possibly 'cutecom').
5518 For instance, try to send
5519 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
5520 Verify you can connect and disconnect from the units while in your
5521 terminal program by sending the escape-disconnect mentioned above.
5524 To set the radio frequency, use the 'c R' command to specify the
5525 radio transceiver configuration parameter. This parameter is computed
5526 using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
5527 the standard calibration reference frequency, 'S', (normally 434.550MHz):
5531 Round the result to the nearest integer value.
5532 As with all 'c' sub-commands, follow this with a 'c w' to write the
5533 change to the parameter block in the on-board flash on
5534 your altimeter board if you want the change to stay in place across reboots.
5537 To set the apogee delay, use the 'c d' command.
5538 As with all 'c' sub-commands, follow this with a 'c w' to write the
5539 change to the parameter block in the on-board DataFlash chip.
5542 To set the main deployment altitude, use the 'c m' command.
5543 As with all 'c' sub-commands, follow this with a 'c w' to write the
5544 change to the parameter block in the on-board DataFlash chip.
5547 To calibrate the radio frequency, connect the UHF antenna port to a
5548 frequency counter, set the board to 434.550MHz, and use the 'C'
5549 command to generate a CW carrier. Wait for the transmitter temperature
5550 to stabilize and the frequency to settle down.
5551 Then, divide 434.550 MHz by the
5552 measured frequency and multiply by the current radio cal value show
5553 in the 'c s' command. For an unprogrammed board, the default value
5554 is 1186611 for cc1111 based products and 7119667 for cc1120
5555 based products. Take the resulting integer and program it using the 'c f'
5556 command. Testing with the 'C' command again should show a carrier
5557 within a few tens of Hertz of the intended frequency.
5558 As with all 'c' sub-commands, follow this with a 'c w' to write the
5559 change to the configuration memory.
5562 Note that the 'reboot' command, which is very useful on the altimeters,
5563 will likely just cause problems with the dongle. The *correct* way
5564 to reset the dongle is just to unplug and re-plug it.
5567 A fun thing to do at the launch site and something you can do while
5568 learning how to use these units is to play with the radio link access
5569 between an altimeter and the TeleDongle. Be aware that you *must* create
5570 some physical separation between the devices, otherwise the link will
5571 not function due to signal overload in the receivers in each device.
5574 Now might be a good time to take a break and read the rest of this
5575 manual, particularly about the two “modes” that the altimeters
5576 can be placed in. TeleMetrum uses the position of the device when booting
5577 up will determine whether the unit is in “pad” or “idle” mode. TeleMini
5578 enters “idle” mode when it receives a command packet within the first 5 seconds
5579 of being powered up, otherwise it enters “pad” mode.
5582 You can access an altimeter in idle mode from the TeleDongle's USB
5583 connection using the radio link
5584 by issuing a 'p' command to the TeleDongle. Practice connecting and
5585 disconnecting ('~~' while using 'cu') from the altimeter. If
5586 you cannot escape out of the “p” command, (by using a '~~' when in
5587 CU) then it is likely that your kernel has issues. Try a newer version.
5590 Using this radio link allows you to configure the altimeter, test
5591 fire e-matches and igniters from the flight line, check pyro-match
5592 continuity and so forth. You can leave the unit turned on while it
5593 is in 'idle mode' and then place the
5594 rocket vertically on the launch pad, walk away and then issue a
5595 reboot command. The altimeter will reboot and start sending data
5596 having changed to the “pad” mode. If the TeleDongle is not receiving
5597 this data, you can disconnect 'cu' from the TeleDongle using the
5598 procedures mentioned above and THEN connect to the TeleDongle from
5599 inside 'ao-view'. If this doesn't work, disconnect from the
5600 TeleDongle, unplug it, and try again after plugging it back in.
5603 In order to reduce the chance of accidental firing of pyrotechnic
5604 charges, the command to fire a charge is intentionally somewhat
5605 difficult to type, and the built-in help is slightly cryptic to
5606 prevent accidental echoing of characters from the help text back at
5607 the board from firing a charge. The command to fire the apogee
5608 drogue charge is 'i DoIt drogue' and the command to fire the main
5609 charge is 'i DoIt main'.
5612 On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
5613 and 'ao-view' will both auditorily announce and visually indicate
5615 Now you can launch knowing that you have a good data path and
5616 good satellite lock for flight data and recovery. Remember
5617 you MUST tell ao-view to connect to the TeleDongle explicitly in
5618 order for ao-view to be able to receive data.
5621 The altimeters provide RDF (radio direction finding) tones on
5622 the pad, during descent and after landing. These can be used to
5623 locate the rocket using a directional antenna; the signal
5624 strength providing an indication of the direction from receiver to rocket.
5627 TeleMetrum also provides GPS tracking data, which can further simplify
5628 locating the rocket once it has landed. (The last good GPS data
5629 received before touch-down will be on the data screen of 'ao-view'.)
5632 Once you have recovered the rocket you can download the eeprom
5633 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
5634 either a USB cable or over the radio link using TeleDongle.
5635 And by following the man page for 'ao-postflight' you can create
5636 various data output reports, graphs, and even KML data to see the
5637 flight trajectory in Google-earth. (Moving the viewing angle making
5638 sure to connect the yellow lines while in Google-earth is the proper
5642 As for ao-view.... some things are in the menu but don't do anything
5643 very useful. The developers have stopped working on ao-view to focus
5644 on a new, cross-platform ground station program. So ao-view may or
5645 may not be updated in the future. Mostly you just use
5646 the Log and Device menus. It has a wonderful display of the incoming
5647 flight data and I am sure you will enjoy what it has to say to you
5648 once you enable the voice output!
5652 <title>Drill Templates</title>
5654 These images, when printed, provide precise templates for the
5655 mounting holes in Altus Metrum flight computers
5658 <title>TeleMega template</title>
5660 TeleMega has overall dimensions of 1.250 x 3.250 inches, and
5661 the mounting holes are sized for use with 4-40 or M3 screws.
5664 <mediaobject id="TeleMegaTemplate">
5666 <imagedata format="SVG" fileref="telemega.svg"
5667 scalefit="0" scale="100" align="center" />
5673 <title>EasyMega template</title>
5675 EasyMega has overall dimensions of 1.250 x 2.250 inches, and
5676 the mounting holes are sized for use with 4-40 or M3 screws.
5679 <mediaobject id="EasyMegaTemplate">
5681 <imagedata format="SVG" fileref="easymega.svg"
5682 scalefit="0" scale="100" align="center" />
5688 <title>TeleMetrum template</title>
5690 TeleMetrum has overall dimensions of 1.000 x 2.750 inches, and the
5691 mounting holes are sized for use with 4-40 or M3 screws.
5694 <mediaobject id="TeleMetrumTemplate">
5696 <imagedata format="SVG" fileref="telemetrum.svg"
5697 scalefit="0" scale="100" align="center" />
5703 <title>TeleMini v2/EasyMini template</title>
5705 TeleMini v2 and EasyMini have overall dimensions of 0.800 x 1.500 inches, and the
5706 mounting holes are sized for use with 4-40 or M3 screws.
5709 <mediaobject id="MiniTemplate">
5711 <imagedata format="SVG" fileref="easymini.svg"
5712 scalefit="0" scale="100" align="center" />
5718 <title>TeleMini v1 template</title>
5720 TeleMini has overall dimensions of 0.500 x 1.500 inches, and the
5721 mounting holes are sized for use with 2-56 or M2 screws.
5724 <mediaobject id="TeleMiniTemplate">
5726 <imagedata format="SVG" fileref="telemini.svg"
5727 scalefit="0" scale="100" align="center" />
5734 <title>Calibration</title>
5736 There are only two calibrations required for TeleMetrum and
5737 TeleMega, and only one for EasyMega, TeleDongle, TeleMini and EasyMini.
5738 All boards are shipped from the factory pre-calibrated, but
5739 the procedures are documented here in case they are ever
5740 needed. Re-calibration is not supported by AltosUI, you must
5741 connect to the board with a serial terminal program and
5742 interact directly with the on-board command interpreter to
5746 <title>Radio Frequency</title>
5748 The radio frequency is synthesized from a clock based on the
5749 crystal on the board. The actual frequency of this oscillator
5750 must be measured to generate a calibration constant. While our
5752 bandwidth is wide enough to allow boards to communicate even when
5753 their oscillators are not on exactly the same frequency, performance
5754 is best when they are closely matched.
5755 Radio frequency calibration requires a calibrated frequency counter.
5756 Fortunately, once set, the variation in frequency due to aging and
5757 temperature changes is small enough that re-calibration by customers
5758 should generally not be required.
5761 To calibrate the radio frequency, connect the UHF antenna
5762 port to a frequency counter, set the board to 434.550MHz,
5763 and use the 'C' command in the on-board command interpreter
5764 to generate a CW carrier. For USB-enabled boards, this is
5765 best done over USB. For TeleMini v1, note that the only way
5766 to escape the 'C' command is via power cycle since the board
5767 will no longer be listening for commands once it starts
5768 generating a CW carrier.
5771 Wait for the transmitter temperature to stabilize and the frequency
5772 to settle down. Then, divide 434.550 MHz by the
5773 measured frequency and multiply by the current radio cal value show
5774 in the 'c s' command. For an unprogrammed board, the default value
5775 is 1186611. Take the resulting integer and program it using the 'c f'
5776 command. Testing with the 'C' command again should show a carrier
5777 within a few tens of Hertz of the intended frequency.
5778 As with all 'c' sub-commands, follow this with a 'c w' to write the
5779 change to the parameter block in the on-board storage chip.
5782 Note that any time you re-do the radio frequency calibration, the
5783 radio frequency is reset to the default 434.550 Mhz. If you want
5784 to use another frequency, you will have to set that again after
5785 calibration is completed.
5789 <title>TeleMetrum, TeleMega and EasyMega Accelerometers</title>
5791 While barometric sensors are factory-calibrated,
5792 accelerometers are not, and so each must be calibrated once
5793 installed in a flight computer. Explicitly calibrating the
5794 accelerometers also allows us to load any compatible device.
5795 We perform a two-point calibration using gravity.
5798 To calibrate the acceleration sensor, use the 'c a 0' command. You
5799 will be prompted to orient the board vertically with the UHF antenna
5800 up and press a key, then to orient the board vertically with the
5801 UHF antenna down and press a key. Note that the accuracy of this
5802 calibration depends primarily on how perfectly vertical and still
5803 the board is held during the cal process. As with all 'c'
5804 sub-commands, follow this with a 'c w' to write the
5805 change to the parameter block in the on-board DataFlash chip.
5808 The +1g and -1g calibration points are included in each telemetry
5809 frame and are part of the header stored in onboard flash to be
5810 downloaded after flight. We always store and return raw ADC
5811 samples for each sensor... so nothing is permanently “lost” or
5812 “damaged” if the calibration is poor.
5815 In the unlikely event an accel cal goes badly, it is possible
5816 that TeleMetrum, TeleMega or EasyMega may always come up in 'pad mode'
5817 and as such not be listening to either the USB or radio link.
5818 If that happens, there is a special hook in the firmware to
5819 force the board back in to 'idle mode' so you can re-do the
5820 cal. To use this hook, you just need to ground the SPI clock
5821 pin at power-on. This pin is available as pin 2 on the 8-pin
5822 companion connector, and pin 1 is ground. So either
5823 carefully install a fine-gauge wire jumper between the two
5824 pins closest to the index hole end of the 8-pin connector, or
5825 plug in the programming cable to the 8-pin connector and use
5826 a small screwdriver or similar to short the two pins closest
5827 to the index post on the 4-pin end of the programming cable,
5828 and power up the board. It should come up in 'idle mode'
5829 (two beeps), allowing a re-cal.
5834 <title>Release Notes</title>
5836 <title>Version 1.4.1</title>
5838 xmlns:xi="http://www.w3.org/2001/XInclude"
5839 href="release-notes-1.4.1.xsl"
5840 xpointer="xpointer(/article/*)"/>
5843 <title>Version 1.5</title>
5845 xmlns:xi="http://www.w3.org/2001/XInclude"
5846 href="release-notes-1.5.xsl"
5847 xpointer="xpointer(/article/*)"/>
5850 <title>Version 1.4</title>
5852 xmlns:xi="http://www.w3.org/2001/XInclude"
5853 href="release-notes-1.4.xsl"
5854 xpointer="xpointer(/article/*)"/>
5857 <title>Version 1.3.2</title>
5859 xmlns:xi="http://www.w3.org/2001/XInclude"
5860 href="release-notes-1.3.2.xsl"
5861 xpointer="xpointer(/article/*)"/>
5864 <title>Version 1.3.1</title>
5866 xmlns:xi="http://www.w3.org/2001/XInclude"
5867 href="release-notes-1.3.1.xsl"
5868 xpointer="xpointer(/article/*)"/>
5871 <title>Version 1.3</title>
5873 xmlns:xi="http://www.w3.org/2001/XInclude"
5874 href="release-notes-1.3.xsl"
5875 xpointer="xpointer(/article/*)"/>
5878 <title>Version 1.2.1</title>
5880 xmlns:xi="http://www.w3.org/2001/XInclude"
5881 href="release-notes-1.2.1.xsl"
5882 xpointer="xpointer(/article/*)"/>
5885 <title>Version 1.2</title>
5887 xmlns:xi="http://www.w3.org/2001/XInclude"
5888 href="release-notes-1.2.xsl"
5889 xpointer="xpointer(/article/*)"/>
5892 <title>Version 1.1.1</title>
5894 xmlns:xi="http://www.w3.org/2001/XInclude"
5895 href="release-notes-1.1.1.xsl"
5896 xpointer="xpointer(/article/*)"/>
5899 <title>Version 1.1</title>
5901 xmlns:xi="http://www.w3.org/2001/XInclude"
5902 href="release-notes-1.1.xsl"
5903 xpointer="xpointer(/article/*)"/>
5906 <title>Version 1.0.1</title>
5908 xmlns:xi="http://www.w3.org/2001/XInclude"
5909 href="release-notes-1.0.1.xsl"
5910 xpointer="xpointer(/article/*)"/>
5913 <title>Version 0.9.2</title>
5915 xmlns:xi="http://www.w3.org/2001/XInclude"
5916 href="release-notes-0.9.2.xsl"
5917 xpointer="xpointer(/article/*)"/>
5920 <title>Version 0.9</title>
5922 xmlns:xi="http://www.w3.org/2001/XInclude"
5923 href="release-notes-0.9.xsl"
5924 xpointer="xpointer(/article/*)"/>
5927 <title>Version 0.8</title>
5929 xmlns:xi="http://www.w3.org/2001/XInclude"
5930 href="release-notes-0.8.xsl"
5931 xpointer="xpointer(/article/*)"/>
5934 <title>Version 0.7.1</title>
5936 xmlns:xi="http://www.w3.org/2001/XInclude"
5937 href="release-notes-0.7.1.xsl"
5938 xpointer="xpointer(/article/*)"/>
5943 <!-- LocalWords: Altusmetrum
projects / fw / altos / blob