1 <?xml version="1.0" encoding="utf-8"?>
2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
3 "/usr/share/xml/docbook/schema/dtd/4.5/docbookx.dtd">
5 <title>The Altus Metrum System</title>
6 <subtitle>An Owner's Manual for Altus Metrum Rocketry Electronics</subtitle>
9 <firstname>Bdale</firstname>
10 <surname>Garbee</surname>
13 <firstname>Keith</firstname>
14 <surname>Packard</surname>
17 <firstname>Bob</firstname>
18 <surname>Finch</surname>
21 <firstname>Anthony</firstname>
22 <surname>Towns</surname>
26 <holder>Bdale Garbee and Keith Packard</holder>
30 <imagedata fileref="../themes/background.png" width="6.0in"/>
35 This document is released under the terms of the
36 <ulink url="http://creativecommons.org/licenses/by-sa/3.0/">
37 Creative Commons ShareAlike 3.0
44 <revnumber>1.6</revnumber>
45 <date>8 January 2015</date>
47 Major release adding TeleDongle v3.0 support.
51 <revnumber>1.5</revnumber>
52 <date>6 September 2014</date>
54 Major release adding EasyMega support.
58 <revnumber>1.4.1</revnumber>
59 <date>20 June 2014</date>
61 Minor release fixing some installation bugs.
65 <revnumber>1.4</revnumber>
66 <date>15 June 2014</date>
68 Major release adding TeleGPS support.
72 <revnumber>1.3.2</revnumber>
73 <date>24 January 2014</date>
75 Bug fixes for TeleMega and AltosUI.
79 <revnumber>1.3.1</revnumber>
80 <date>21 January 2014</date>
82 Bug fixes for TeleMega and TeleMetrum v2.0 along with a few
83 small UI improvements.
87 <revnumber>1.3</revnumber>
88 <date>12 November 2013</date>
90 Updated for software version 1.3. Version 1.3 adds support
91 for TeleMega, TeleMetrum v2.0, TeleMini v2.0 and EasyMini
92 and fixes bugs in AltosUI and the AltOS firmware.
96 <revnumber>1.2.1</revnumber>
97 <date>21 May 2013</date>
99 Updated for software version 1.2. Version 1.2 adds support
100 for TeleBT and AltosDroid. It also adds a few minor features
101 and fixes bugs in AltosUI and the AltOS firmware.
105 <revnumber>1.2</revnumber>
106 <date>18 April 2013</date>
108 Updated for software version 1.2. Version 1.2 adds support
109 for MicroPeak and the MicroPeak USB interface.
113 <revnumber>1.1.1</revnumber>
114 <date>16 September 2012</date>
116 Updated for software version 1.1.1 Version 1.1.1 fixes a few
117 bugs found in version 1.1.
121 <revnumber>1.1</revnumber>
122 <date>13 September 2012</date>
124 Updated for software version 1.1. Version 1.1 has new
125 features but is otherwise compatible with version 1.0.
129 <revnumber>1.0</revnumber>
130 <date>24 August 2011</date>
132 Updated for software version 1.0. Note that 1.0 represents a
133 telemetry format change, meaning both ends of a link
134 (TeleMetrum/TeleMini and TeleDongle) must be updated or
135 communications will fail.
139 <revnumber>0.9</revnumber>
140 <date>18 January 2011</date>
142 Updated for software version 0.9. Note that 0.9 represents a
143 telemetry format change, meaning both ends of a link (TeleMetrum and
144 TeleDongle) must be updated or communications will fail.
148 <revnumber>0.8</revnumber>
149 <date>24 November 2010</date>
150 <revremark>Updated for software version 0.8 </revremark>
155 <title>Acknowledgments</title>
157 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing “The
158 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
159 Kit” which formed the basis of the original Getting Started chapter
160 in this manual. Bob was one of our first customers for a production
161 TeleMetrum, and his continued enthusiasm and contributions
162 are immensely gratifying and highly appreciated!
165 And thanks to Anthony (AJ) Towns for major contributions including
166 the AltosUI graphing and site map code and associated documentation.
167 Free software means that our customers and friends can become our
168 collaborators, and we certainly appreciate this level of
172 Have fun using these products, and we hope to meet all of you
173 out on the rocket flight line somewhere.
176 NAR #87103, TRA #12201
178 Keith Packard, KD7SQG
179 NAR #88757, TRA #12200
184 <title>Introduction and Overview</title>
186 Welcome to the Altus Metrum community! Our circuits and software reflect
187 our passion for both hobby rocketry and Free Software. We hope their
188 capabilities and performance will delight you in every way, but by
189 releasing all of our hardware and software designs under open licenses,
190 we also hope to empower you to take as active a role in our collective
194 The first device created for our community was TeleMetrum, a dual
195 deploy altimeter with fully integrated GPS and radio telemetry
196 as standard features, and a “companion interface” that will
197 support optional capabilities in the future. The latest version
198 of TeleMetrum, v2.0, has all of the same features but with
199 improved sensors and radio to offer increased performance.
202 Our second device was TeleMini, a dual deploy altimeter with
203 radio telemetry and radio direction finding. The first version
204 of this device was only 13mm by 38mm (½ inch by 1½ inches) and
205 could fit easily in an 18mm air-frame. The latest version, v2.0,
206 includes a beeper, USB data download and extended on-board
207 flight logging, along with an improved barometric sensor.
210 TeleMega is our most sophisticated device, including six pyro
211 channels (four of which are fully programmable), integrated GPS,
212 integrated gyroscopes for staging/air-start inhibit and high
213 performance telemetry.
216 EasyMini is a dual-deploy altimeter with logging and built-in
220 EasyMega is essentially a TeleMega board with the GPS receiver
221 and telemetry transmitter removed. It offers the same 6 pyro
222 channels and integrated gyroscopes for staging/air-start inhibit.
225 TeleDongle v0.2 was our first ground station, providing a USB to RF
226 interfaces for communicating with the altimeters. Combined with
227 your choice of antenna and notebook computer, TeleDongle and our
228 associated user interface software form a complete ground
229 station capable of logging and displaying in-flight telemetry,
230 aiding rocket recovery, then processing and archiving flight
231 data for analysis and review. The latest version, TeleDongle
232 v3, has all new electronics with a higher performance radio
236 For a slightly more portable ground station experience that also
237 provides direct rocket recovery support, TeleBT offers flight
238 monitoring and data logging using a Bluetooth™ connection between
239 the receiver and an Android device that has the AltosDroid
240 application installed from the Google Play store.
243 More products will be added to the Altus Metrum family over time, and
244 we currently envision that this will be a single, comprehensive manual
245 for the entire product family.
249 <title>Getting Started</title>
251 The first thing to do after you check the inventory of parts in your
252 “starter kit” is to charge the battery.
255 For TeleMetrum, TeleMega and EasyMega, the battery can be charged by plugging it into the
256 corresponding socket of the device and then using the USB
257 cable to plug the flight computer into your computer's USB socket. The
258 on-board circuitry will charge the battery whenever it is plugged
259 in, because the on-off switch does NOT control the
263 On TeleMetrum v1 boards, when the GPS chip is initially
264 searching for satellites, TeleMetrum will consume more current
265 than it pulls from the USB port, so the battery must be
266 attached in order to get satellite lock. Once GPS is locked,
267 the current consumption goes back down enough to enable charging
268 while running. So it's a good idea to fully charge the battery
269 as your first item of business so there is no issue getting and
270 maintaining satellite lock. The yellow charge indicator led
271 will go out when the battery is nearly full and the charger goes
272 to trickle charge. It can take several hours to fully recharge a
273 deeply discharged battery.
276 TeleMetrum v2.0, TeleMega and EasyMega use a higher power battery charger,
277 allowing them to charge the battery while running the board at
278 maximum power. When the battery is charging, or when the board
279 is consuming a lot of power, the red LED will be lit. When the
280 battery is fully charged, the green LED will be lit. When the
281 battery is damaged or missing, both LEDs will be lit, which
285 The Lithium Polymer TeleMini and EasyMini battery can be charged by
286 disconnecting it from the board and plugging it into a
287 standalone battery charger such as the LipoCharger product
288 included in TeleMini Starter Kits, and connecting that via a USB
289 cable to a laptop or other USB power source.
292 You can also choose to use another battery with TeleMini v2.0
293 and EasyMini, anything supplying between 4 and 12 volts should
294 work fine (like a standard 9V battery), but if you are planning
295 to fire pyro charges, ground testing is required to verify that
296 the battery supplies enough current to fire your chosen e-matches.
299 The other active device in the starter kit is the TeleDongle USB to
300 RF interface. If you plug it in to your Mac or Linux computer it should
301 “just work”, showing up as a serial port device. Windows systems need
302 driver information that is part of the AltOS download to know that the
303 existing USB modem driver will work. We therefore recommend installing
304 our software before plugging in TeleDongle if you are using a Windows
305 computer. If you are using an older version of Linux and are having
306 problems, try moving to a fresher kernel (2.6.33 or newer).
309 Next you should obtain and install the AltOS software. The AltOS
310 distribution includes the AltosUI ground station program, current
312 images for all of the hardware, and a number of standalone
313 utilities that are rarely needed. Pre-built binary packages are
314 available for Linux, Microsoft Windows, and recent MacOSX
315 versions. Full source code and build instructions are also
316 available. The latest version may always be downloaded from
317 <ulink url="http://altusmetrum.org/AltOS"/>.
320 If you're using a TeleBT instead of the TeleDongle, you'll want to
321 install the AltosDroid application from the Google Play store on an
322 Android device. You don't need a data plan to use AltosDroid, but
323 without network access, the Map view will be less useful as it
324 won't contain any map data. You can also use TeleBT connected
325 over USB with your laptop computer; it acts exactly like a
326 TeleDongle. Anywhere this manual talks about TeleDongle, you can
327 also read that as 'and TeleBT when connected via USB'.
331 <title>Handling Precautions</title>
333 All Altus Metrum products are sophisticated electronic devices.
334 When handled gently and properly installed in an air-frame, they
335 will deliver impressive results. However, as with all electronic
336 devices, there are some precautions you must take.
339 The Lithium Polymer rechargeable batteries have an
340 extraordinary power density. This is great because we can fly with
341 much less battery mass than if we used alkaline batteries or previous
342 generation rechargeable batteries... but if they are punctured
343 or their leads are allowed to short, they can and will release their
345 Thus we recommend that you take some care when handling our batteries
346 and consider giving them some extra protection in your air-frame. We
347 often wrap them in suitable scraps of closed-cell packing foam before
348 strapping them down, for example.
351 The barometric sensors used on all of our flight computers are
352 sensitive to sunlight. In normal mounting situations, the baro sensor
353 and all of the other surface mount components
354 are “down” towards whatever the underlying mounting surface is, so
355 this is not normally a problem. Please consider this when designing an
356 installation in an air-frame with a see-through plastic payload bay. It
357 is particularly important to
358 consider this with TeleMini v1.0, both because the baro sensor is on the
359 “top” of the board, and because many model rockets with payload bays
360 use clear plastic for the payload bay! Replacing these with an opaque
361 cardboard tube, painting them, or wrapping them with a layer of masking
362 tape are all reasonable approaches to keep the sensor out of direct
366 The barometric sensor sampling port must be able to “breathe”,
367 both by not being covered by foam or tape or other materials that might
368 directly block the hole on the top of the sensor, and also by having a
369 suitable static vent to outside air.
372 As with all other rocketry electronics, Altus Metrum altimeters must
373 be protected from exposure to corrosive motor exhaust and ejection
378 <title>Altus Metrum Hardware</title>
380 <title>General Usage Instructions</title>
382 Here are general instructions for hooking up an Altus Metrum
383 flight computer. Instructions specific to each model will be
384 found in the section devoted to that model below.
387 To prevent electrical interference from affecting the
388 operation of the flight computer, it's important to always
389 twist pairs of wires connected to the board. Twist the switch
390 leads, the pyro leads and the battery leads. This reduces
391 interference through a mechanism called common mode rejection.
394 <title>Hooking Up Lithium Polymer Batteries</title>
396 All Altus Metrum flight computers have a two pin JST PH
397 series connector to connect up a single-cell Lithium Polymer
398 cell (3.7V nominal). You can purchase matching batteries
399 from the Altus Metrum store, or other vendors, or you can
400 make your own. Pin 1 of the connector is positive, pin 2 is
401 negative. Spark Fun sells a cable with the connector
402 attached, which they call a <ulink
403 url="https://www.sparkfun.com/products/9914">JST Jumper 2
404 Wire Assembly</ulink>.
407 Many RC vendors also sell lithium polymer batteries with
408 this same connector. All that we have found use the opposite
409 polarity, and if you use them that way, you will damage or
410 destroy the flight computer.
414 <title>Hooking Up Pyro Charges</title>
416 Altus Metrum flight computers always have two screws for
417 each pyro charge. This means you shouldn't need to put two
418 wires into a screw terminal or connect leads from pyro
419 charges together externally.
422 On the flight computer, one lead from each charge is hooked
423 to the positive battery terminal through the power switch.
424 The other lead is connected through the pyro circuit, which
425 is connected to the negative battery terminal when the pyro
430 <title>Hooking Up a Power Switch</title>
432 Altus Metrum flight computers need an external power switch
433 to turn them on. This disconnects both the computer and the
434 pyro charges from the battery, preventing the charges from
435 firing when in the Off position. The switch is in-line with
436 the positive battery terminal.
439 <title>Using an External Active Switch Circuit</title>
441 You can use an active switch circuit, such as the
442 Featherweight Magnetic Switch, with any Altus Metrum
443 flight computer. These require three connections, one to
444 the battery, one to the positive power input on the flight
445 computer and one to ground. Find instructions on how to
446 hook these up for each flight computer below. The follow
447 the instructions that come with your active switch to
453 <title>Using a Separate Pyro Battery</title>
455 As mentioned above in the section on hooking up pyro
456 charges, one lead for each of the pyro charges is connected
457 through the power switch directly to the positive battery
458 terminal. The other lead is connected to the pyro circuit,
459 which connects it to the negative battery terminal when the
460 pyro circuit is fired. The pyro circuit on all of the flight
461 computers is designed to handle up to 16V.
464 To use a separate pyro battery, connect the negative pyro
465 battery terminal to the flight computer ground terminal,
466 the positive battery terminal to the igniter and the other
467 igniter lead to the negative pyro terminal on the flight
468 computer. When the pyro channel fires, it will complete the
469 circuit between the negative pyro terminal and the ground
470 terminal, firing the igniter. Specific instructions on how
471 to hook this up will be found in each section below.
475 <title>Using a Different Kind of Battery</title>
477 EasyMini and TeleMini v2 are designed to use either a
478 lithium polymer battery or any other battery producing
479 between 4 and 12 volts, such as a rectangular 9V
480 battery. TeleMega, EasyMega and TeleMetrum are not designed for this,
481 and must only be powered by a lithium polymer battery. Find
482 instructions on how to use other batteries in the EasyMini
483 and TeleMini sections below.
488 <title>Specifications</title>
490 Here's the full set of Altus Metrum products, both in
491 production and retired.
494 <title>Altus Metrum Electronics</title>
495 <?dbfo keep-together="always"?>
496 <tgroup cols='8' align='center' colsep='1' rowsep='1'>
497 <colspec align='center' colwidth='*' colname='Device'/>
498 <colspec align='center' colwidth='*' colname='Barometer'/>
499 <colspec align='center' colwidth='*' colname='Z-axis accelerometer'/>
500 <colspec align='center' colwidth='*' colname='GPS'/>
501 <colspec align='center' colwidth='*' colname='3D sensors'/>
502 <colspec align='center' colwidth='*' colname='Storage'/>
503 <colspec align='center' colwidth='*' colname='RF'/>
504 <colspec align='center' colwidth='*' colname='Battery'/>
507 <entry align='center'>Device</entry>
508 <entry align='center'>Barometer</entry>
509 <entry align='center'>Z-axis accelerometer</entry>
510 <entry align='center'>GPS</entry>
511 <entry align='center'>3D sensors</entry>
512 <entry align='center'>Storage</entry>
513 <entry align='center'>RF Output</entry>
514 <entry align='center'>Battery</entry>
519 <entry>TeleMetrum v1.0</entry>
520 <entry><para>MP3H6115 10km (33k')</para></entry>
521 <entry><para>MMA2202 50g</para></entry>
522 <entry>SkyTraq</entry>
529 <entry>TeleMetrum v1.1</entry>
530 <entry><para>MP3H6115 10km (33k')</para></entry>
531 <entry><para>MMA2202 50g</para></entry>
532 <entry>SkyTraq</entry>
539 <entry>TeleMetrum v1.2</entry>
540 <entry><para>MP3H6115 10km (33k')</para></entry>
541 <entry><para>ADXL78 70g</para></entry>
542 <entry>SkyTraq</entry>
549 <entry>TeleMetrum v2.0</entry>
550 <entry><para>MS5607 30km (100k')</para></entry>
551 <entry><para>MMA6555 102g</para></entry>
552 <entry>uBlox Max-7Q</entry>
559 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
560 <entry><para>MP3H6115 10km (33k')</para></entry>
569 <entry>TeleMini <?linebreak?>v2.0</entry>
570 <entry><para>MS5607 30km (100k')</para></entry>
576 <entry>3.7-12V</entry>
579 <entry>EasyMini <?linebreak?>v1.0</entry>
580 <entry><para>MS5607 30km (100k')</para></entry>
586 <entry>3.7-12V</entry>
589 <entry>TeleMega <?linebreak?>v1.0</entry>
590 <entry><para>MS5607 30km (100k')</para></entry>
591 <entry><para>MMA6555 102g</para></entry>
592 <entry>uBlox Max-7Q</entry>
593 <entry><para>MPU6000 HMC5883</para></entry>
599 <entry>EasyMega <?linebreak?>v1.0</entry>
600 <entry><para>MS5607 30km (100k')</para></entry>
601 <entry><para>MMA6555 102g</para></entry>
603 <entry><para>MPU6000 HMC5883</para></entry>
612 <title>Altus Metrum Boards</title>
613 <?dbfo keep-together="always"?>
614 <tgroup cols='6' align='center' colsep='1' rowsep='1'>
615 <colspec align='center' colwidth='*' colname='Device'/>
616 <colspec align='center' colwidth='*' colname='Connectors'/>
617 <colspec align='center' colwidth='*' colname='Screw Terminals'/>
618 <colspec align='center' colwidth='*' colname='Width'/>
619 <colspec align='center' colwidth='*' colname='Length'/>
620 <colspec align='center' colwidth='*' colname='Tube Size'/>
623 <entry align='center'>Device</entry>
624 <entry align='center'>Connectors</entry>
625 <entry align='center'>Screw Terminals</entry>
626 <entry align='center'>Width</entry>
627 <entry align='center'>Length</entry>
628 <entry align='center'>Tube Size</entry>
633 <entry>TeleMetrum</entry>
637 Companion<?linebreak?>
641 <entry><para>Apogee pyro <?linebreak?>Main pyro <?linebreak?>Switch</para></entry>
642 <entry>1 inch (2.54cm)</entry>
643 <entry>2 ¾ inch (6.99cm)</entry>
644 <entry>29mm coupler</entry>
647 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
654 Apogee pyro <?linebreak?>
657 <entry>½ inch (1.27cm)</entry>
658 <entry>1½ inch (3.81cm)</entry>
659 <entry>18mm coupler</entry>
662 <entry>TeleMini <?linebreak?>v2.0</entry>
670 Apogee pyro <?linebreak?>
671 Main pyro <?linebreak?>
672 Battery <?linebreak?>
675 <entry>0.8 inch (2.03cm)</entry>
676 <entry>1½ inch (3.81cm)</entry>
677 <entry>24mm coupler</entry>
680 <entry>EasyMini</entry>
687 Apogee pyro <?linebreak?>
688 Main pyro <?linebreak?>
689 Battery <?linebreak?>
692 <entry>0.8 inch (2.03cm)</entry>
693 <entry>1½ inch (3.81cm)</entry>
694 <entry>24mm coupler</entry>
697 <entry>TeleMega</entry>
701 Companion<?linebreak?>
706 Apogee pyro <?linebreak?>
707 Main pyro<?linebreak?>
708 Pyro A-D<?linebreak?>
712 <entry>1¼ inch (3.18cm)</entry>
713 <entry>3¼ inch (8.26cm)</entry>
714 <entry>38mm coupler</entry>
717 <entry>EasyMega</entry>
720 Companion<?linebreak?>
725 Apogee pyro <?linebreak?>
726 Main pyro<?linebreak?>
727 Pyro A-D<?linebreak?>
731 <entry>1¼ inch (3.18cm)</entry>
732 <entry>2¼ inch (5.62cm)</entry>
733 <entry>38mm coupler</entry>
740 <title>TeleMetrum</title>
744 <imagedata fileref="telemetrum-v1.1-thside.jpg" width="5.5in" scalefit="1"/>
749 TeleMetrum is a 1 inch by 2¾ inch circuit board. It was designed to
750 fit inside coupler for 29mm air-frame tubing, but using it in a tube that
751 small in diameter may require some creativity in mounting and wiring
752 to succeed! The presence of an accelerometer means TeleMetrum should
753 be aligned along the flight axis of the airframe, and by default the ¼
754 wave UHF wire antenna should be on the nose-cone end of the board. The
755 antenna wire is about 7 inches long, and wiring for a power switch and
756 the e-matches for apogee and main ejection charges depart from the
757 fin can end of the board, meaning an ideal “simple” avionics
758 bay for TeleMetrum should have at least 10 inches of interior length.
761 <title>TeleMetrum Screw Terminals</title>
763 TeleMetrum has six screw terminals on the end of the board
764 opposite the telemetry antenna. Two are for the power
765 switch, and two each for the apogee and main igniter
766 circuits. Using the picture above and starting from the top,
767 the terminals are as follows:
770 <title>TeleMetrum Screw Terminals</title>
771 <?dbfo keep-together="always"?>
772 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
773 <colspec align='center' colwidth='*' colname='Pin #'/>
774 <colspec align='center' colwidth='2*' colname='Pin Name'/>
775 <colspec align='left' colwidth='5*' colname='Description'/>
778 <entry align='center'>Terminal #</entry>
779 <entry align='center'>Terminal Name</entry>
780 <entry align='center'>Description</entry>
786 <entry>Switch Output</entry>
787 <entry>Switch connection to flight computer</entry>
791 <entry>Switch Input</entry>
792 <entry>Switch connection to positive battery terminal</entry>
796 <entry>Main +</entry>
797 <entry>Main pyro channel common connection to battery +</entry>
801 <entry>Main -</entry>
802 <entry>Main pyro channel connection to pyro circuit</entry>
806 <entry>Apogee +</entry>
807 <entry>Apogee pyro channel common connection to battery +</entry>
811 <entry>Apogee -</entry>
812 <entry>Apogee pyro channel connection to pyro circuit</entry>
819 <title>Using a Separate Pyro Battery with TeleMetrum</title>
821 As described above, using an external pyro battery involves
822 connecting the negative battery terminal to the flight
823 computer ground, connecting the positive battery terminal to
824 one of the igniter leads and connecting the other igniter
825 lead to the per-channel pyro circuit connection.
828 To connect the negative battery terminal to the TeleMetrum
829 ground, insert a small piece of wire, 24 to 28 gauge
830 stranded, into the GND hole just above the screw terminal
831 strip and solder it in place.
834 Connecting the positive battery terminal to the pyro
835 charges must be done separate from TeleMetrum, by soldering
836 them together or using some other connector.
839 The other lead from each pyro charge is then inserted into
840 the appropriate per-pyro channel screw terminal (terminal 4 for the
841 Main charge, terminal 6 for the Apogee charge).
845 <title>Using an Active Switch with TeleMetrum</title>
847 As explained above, an external active switch requires three
848 connections, one to the positive battery terminal, one to
849 the flight computer positive input and one to ground.
852 The positive battery terminal is available on screw terminal
853 2, the positive flight computer input is on terminal 1. To
854 hook a lead to ground, solder a piece of wire, 24 to 28
855 gauge stranded, to the GND hole just above terminal 1.
860 <title>TeleMini v1.0</title>
864 <imagedata fileref="telemini-v1-top.jpg" width="5.5in" scalefit="1"/>
869 TeleMini v1.0 is ½ inches by 1½ inches. It was
870 designed to fit inside an 18mm air-frame tube, but using it in
871 a tube that small in diameter may require some creativity in
872 mounting and wiring to succeed! Since there is no
873 accelerometer, TeleMini can be mounted in any convenient
874 orientation. The default ¼ wave UHF wire antenna attached to
875 the center of one end of the board is about 7 inches long. Two
876 wires for the power switch are connected to holes in the
877 middle of the board. Screw terminals for the e-matches for
878 apogee and main ejection charges depart from the other end of
879 the board, meaning an ideal “simple” avionics bay for TeleMini
880 should have at least 9 inches of interior length.
883 <title>TeleMini v1.0 Screw Terminals</title>
885 TeleMini v1.0 has four screw terminals on the end of the
886 board opposite the telemetry antenna. Two are for the apogee
887 and two are for main igniter circuits. There are also wires
888 soldered to the board for the power switch. Using the
889 picture above and starting from the top for the terminals
890 and from the left for the power switch wires, the
891 connections are as follows:
894 <title>TeleMini v1.0 Connections</title>
895 <?dbfo keep-together="always"?>
896 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
897 <colspec align='center' colwidth='*' colname='Pin #'/>
898 <colspec align='center' colwidth='2*' colname='Pin Name'/>
899 <colspec align='left' colwidth='5*' colname='Description'/>
902 <entry align='center'>Terminal #</entry>
903 <entry align='center'>Terminal Name</entry>
904 <entry align='center'>Description</entry>
910 <entry>Apogee -</entry>
911 <entry>Apogee pyro channel connection to pyro circuit</entry>
915 <entry>Apogee +</entry>
916 <entry>Apogee pyro channel common connection to battery +</entry>
920 <entry>Main -</entry>
921 <entry>Main pyro channel connection to pyro circuit</entry>
925 <entry>Main +</entry>
926 <entry>Main pyro channel common connection to battery +</entry>
930 <entry>Switch Output</entry>
931 <entry>Switch connection to flight computer</entry>
935 <entry>Switch Input</entry>
936 <entry>Switch connection to positive battery terminal</entry>
943 <title>Using a Separate Pyro Battery with TeleMini v1.0</title>
945 As described above, using an external pyro battery involves
946 connecting the negative battery terminal to the flight
947 computer ground, connecting the positive battery terminal to
948 one of the igniter leads and connecting the other igniter
949 lead to the per-channel pyro circuit connection. Because
950 there is no solid ground connection to use on TeleMini, this
954 The only available ground connection on TeleMini v1.0 are
955 the two mounting holes next to the telemetry
956 antenna. Somehow connect a small piece of wire to one of
957 those holes and hook it to the negative pyro battery terminal.
960 Connecting the positive battery terminal to the pyro
961 charges must be done separate from TeleMini v1.0, by soldering
962 them together or using some other connector.
965 The other lead from each pyro charge is then inserted into
966 the appropriate per-pyro channel screw terminal (terminal 3 for the
967 Main charge, terminal 1 for the Apogee charge).
971 <title>Using an Active Switch with TeleMini v1.0</title>
973 As explained above, an external active switch requires three
974 connections, one to the positive battery terminal, one to
975 the flight computer positive input and one to ground. Again,
976 because TeleMini doesn't have any good ground connection,
977 this is not recommended.
980 The positive battery terminal is available on the Right
981 power switch wire, the positive flight computer input is on
982 the left power switch wire. Hook a lead to either of the
983 mounting holes for a ground connection.
988 <title>TeleMini v2.0</title>
992 <imagedata fileref="telemini-v2-top.jpg" width="5.5in" scalefit="1"/>
997 TeleMini v2.0 is 0.8 inches by 1½ inches. It adds more
998 on-board data logging memory, a built-in USB connector and
999 screw terminals for the battery and power switch. The larger
1000 board fits in a 24mm coupler. There's also a battery connector
1001 for a LiPo battery if you want to use one of those.
1004 <title>TeleMini v2.0 Screw Terminals</title>
1006 TeleMini v2.0 has two sets of four screw terminals on the end of the
1007 board opposite the telemetry antenna. Using the picture
1008 above, the top four have connections for the main pyro
1009 circuit and an external battery and the bottom four have
1010 connections for the apogee pyro circuit and the power
1011 switch. Counting from the left, the connections are as follows:
1014 <title>TeleMini v2.0 Connections</title>
1015 <?dbfo keep-together="always"?>
1016 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
1017 <colspec align='center' colwidth='*' colname='Pin #'/>
1018 <colspec align='center' colwidth='2*' colname='Pin Name'/>
1019 <colspec align='left' colwidth='5*' colname='Description'/>
1022 <entry align='center'>Terminal #</entry>
1023 <entry align='center'>Terminal Name</entry>
1024 <entry align='center'>Description</entry>
1029 <entry>Top 1</entry>
1030 <entry>Main -</entry>
1031 <entry>Main pyro channel connection to pyro circuit</entry>
1034 <entry>Top 2</entry>
1035 <entry>Main +</entry>
1036 <entry>Main pyro channel common connection to battery +</entry>
1039 <entry>Top 3</entry>
1040 <entry>Battery +</entry>
1041 <entry>Positive external battery terminal</entry>
1044 <entry>Top 4</entry>
1045 <entry>Battery -</entry>
1046 <entry>Negative external battery terminal</entry>
1049 <entry>Bottom 1</entry>
1050 <entry>Apogee -</entry>
1051 <entry>Apogee pyro channel connection to pyro circuit</entry>
1054 <entry>Bottom 2</entry>
1055 <entry>Apogee +</entry>
1056 <entry>Apogee pyro channel common connection to
1060 <entry>Bottom 3</entry>
1061 <entry>Switch Output</entry>
1062 <entry>Switch connection to flight computer</entry>
1065 <entry>Bottom 4</entry>
1066 <entry>Switch Input</entry>
1067 <entry>Switch connection to positive battery terminal</entry>
1074 <title>Using a Separate Pyro Battery with TeleMini v2.0</title>
1076 As described above, using an external pyro battery involves
1077 connecting the negative battery terminal to the flight
1078 computer ground, connecting the positive battery terminal to
1079 one of the igniter leads and connecting the other igniter
1080 lead to the per-channel pyro circuit connection.
1083 To connect the negative pyro battery terminal to TeleMini
1084 ground, connect it to the negative external battery
1085 connection, top terminal 4.
1088 Connecting the positive battery terminal to the pyro
1089 charges must be done separate from TeleMini v2.0, by soldering
1090 them together or using some other connector.
1093 The other lead from each pyro charge is then inserted into
1094 the appropriate per-pyro channel screw terminal (top
1095 terminal 1 for the Main charge, bottom terminal 1 for the
1100 <title>Using an Active Switch with TeleMini v2.0</title>
1102 As explained above, an external active switch requires three
1103 connections, one to the positive battery terminal, one to
1104 the flight computer positive input and one to ground. Use
1105 the negative external battery connection, top terminal 4 for
1109 The positive battery terminal is available on bottom
1110 terminal 4, the positive flight computer input is on the
1116 <title>EasyMini</title>
1120 <imagedata fileref="easymini-top.jpg" width="5.5in" scalefit="1"/>
1125 EasyMini is built on a 0.8 inch by 1½ inch circuit board. It's
1126 designed to fit in a 24mm coupler tube. The connectors and
1127 screw terminals match TeleMini v2.0, so you can easily swap between
1128 EasyMini and TeleMini.
1131 <title>EasyMini Screw Terminals</title>
1133 EasyMini has two sets of four screw terminals on the end of the
1134 board opposite the telemetry antenna. Using the picture
1135 above, the top four have connections for the main pyro
1136 circuit and an external battery and the bottom four have
1137 connections for the apogee pyro circuit and the power
1138 switch. Counting from the left, the connections are as follows:
1141 <title>EasyMini Connections</title>
1142 <?dbfo keep-together="always"?>
1143 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
1144 <colspec align='center' colwidth='*' colname='Pin #'/>
1145 <colspec align='center' colwidth='2*' colname='Pin Name'/>
1146 <colspec align='left' colwidth='5*' colname='Description'/>
1149 <entry align='center'>Terminal #</entry>
1150 <entry align='center'>Terminal Name</entry>
1151 <entry align='center'>Description</entry>
1156 <entry>Top 1</entry>
1157 <entry>Main -</entry>
1158 <entry>Main pyro channel connection to pyro circuit</entry>
1161 <entry>Top 2</entry>
1162 <entry>Main +</entry>
1163 <entry>Main pyro channel common connection to battery +</entry>
1166 <entry>Top 3</entry>
1167 <entry>Battery +</entry>
1168 <entry>Positive external battery terminal</entry>
1171 <entry>Top 4</entry>
1172 <entry>Battery -</entry>
1173 <entry>Negative external battery terminal</entry>
1176 <entry>Bottom 1</entry>
1177 <entry>Apogee -</entry>
1178 <entry>Apogee pyro channel connection to pyro circuit</entry>
1181 <entry>Bottom 2</entry>
1182 <entry>Apogee +</entry>
1183 <entry>Apogee pyro channel common connection to
1187 <entry>Bottom 3</entry>
1188 <entry>Switch Output</entry>
1189 <entry>Switch connection to flight computer</entry>
1192 <entry>Bottom 4</entry>
1193 <entry>Switch Input</entry>
1194 <entry>Switch connection to positive battery terminal</entry>
1201 <title>Using a Separate Pyro Battery with EasyMini</title>
1203 As described above, using an external pyro battery involves
1204 connecting the negative battery terminal to the flight
1205 computer ground, connecting the positive battery terminal to
1206 one of the igniter leads and connecting the other igniter
1207 lead to the per-channel pyro circuit connection.
1210 To connect the negative pyro battery terminal to TeleMini
1211 ground, connect it to the negative external battery
1212 connection, top terminal 4.
1215 Connecting the positive battery terminal to the pyro
1216 charges must be done separate from EasyMini, by soldering
1217 them together or using some other connector.
1220 The other lead from each pyro charge is then inserted into
1221 the appropriate per-pyro channel screw terminal (top
1222 terminal 1 for the Main charge, bottom terminal 1 for the
1227 <title>Using an Active Switch with EasyMini</title>
1229 As explained above, an external active switch requires three
1230 connections, one to the positive battery terminal, one to
1231 the flight computer positive input and one to ground. Use
1232 the negative external battery connection, top terminal 4 for
1236 The positive battery terminal is available on bottom
1237 terminal 4, the positive flight computer input is on the
1243 <title>TeleMega</title>
1247 <imagedata fileref="telemega-v1.0-top.jpg" width="5.5in" scalefit="1"/>
1252 TeleMega is a 1¼ inch by 3¼ inch circuit board. It was
1253 designed to easily fit in a 38mm coupler. Like TeleMetrum,
1254 TeleMega has an accelerometer and so it must be mounted so that
1255 the board is aligned with the flight axis. It can be mounted
1256 either antenna up or down.
1259 <title>TeleMega Screw Terminals</title>
1261 TeleMega has two sets of nine screw terminals on the end of
1262 the board opposite the telemetry antenna. They are as follows:
1265 <title>TeleMega Screw Terminals</title>
1266 <?dbfo keep-together="always"?>
1267 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
1268 <colspec align='center' colwidth='*' colname='Pin #'/>
1269 <colspec align='center' colwidth='2*' colname='Pin Name'/>
1270 <colspec align='left' colwidth='5*' colname='Description'/>
1273 <entry align='center'>Terminal #</entry>
1274 <entry align='center'>Terminal Name</entry>
1275 <entry align='center'>Description</entry>
1280 <entry>Top 1</entry>
1281 <entry>Switch Input</entry>
1282 <entry>Switch connection to positive battery terminal</entry>
1285 <entry>Top 2</entry>
1286 <entry>Switch Output</entry>
1287 <entry>Switch connection to flight computer</entry>
1290 <entry>Top 3</entry>
1292 <entry>Ground connection for use with external active switch</entry>
1295 <entry>Top 4</entry>
1296 <entry>Main -</entry>
1297 <entry>Main pyro channel connection to pyro circuit</entry>
1300 <entry>Top 5</entry>
1301 <entry>Main +</entry>
1302 <entry>Main pyro channel common connection to battery +</entry>
1305 <entry>Top 6</entry>
1306 <entry>Apogee -</entry>
1307 <entry>Apogee pyro channel connection to pyro circuit</entry>
1310 <entry>Top 7</entry>
1311 <entry>Apogee +</entry>
1312 <entry>Apogee pyro channel common connection to battery +</entry>
1315 <entry>Top 8</entry>
1317 <entry>D pyro channel connection to pyro circuit</entry>
1320 <entry>Top 9</entry>
1322 <entry>D pyro channel common connection to battery +</entry>
1325 <entry>Bottom 1</entry>
1327 <entry>Ground connection for negative pyro battery terminal</entry>
1330 <entry>Bottom 2</entry>
1332 <entry>Positive pyro battery terminal</entry>
1335 <entry>Bottom 3</entry>
1338 Power switch output. Use to connect main battery to
1343 <entry>Bottom 4</entry>
1345 <entry>A pyro channel connection to pyro circuit</entry>
1348 <entry>Bottom 5</entry>
1350 <entry>A pyro channel common connection to battery +</entry>
1353 <entry>Bottom 6</entry>
1355 <entry>B pyro channel connection to pyro circuit</entry>
1358 <entry>Bottom 7</entry>
1360 <entry>B pyro channel common connection to battery +</entry>
1363 <entry>Bottom 8</entry>
1365 <entry>C pyro channel connection to pyro circuit</entry>
1368 <entry>Bottom 9</entry>
1370 <entry>C pyro channel common connection to battery +</entry>
1377 <title>Using a Separate Pyro Battery with TeleMega</title>
1379 TeleMega provides explicit support for an external pyro
1380 battery. All that is required is to remove the jumper
1381 between the lipo terminal (Bottom 3) and the pyro terminal
1382 (Bottom 2). Then hook the negative pyro battery terminal to ground
1383 (Bottom 1) and the positive pyro battery to the pyro battery
1384 input (Bottom 2). You can then use the existing pyro screw
1385 terminals to hook up all of the pyro charges.
1389 <title>Using Only One Battery With TeleMega</title>
1391 Because TeleMega has built-in support for a separate pyro
1392 battery, if you want to fly with just one battery running
1393 both the computer and firing the charges, you need to
1394 connect the flight computer battery to the pyro
1395 circuit. TeleMega has two screw terminals for this—hook a
1396 wire from the Lipo terminal (Bottom 3) to the Pyro terminal
1401 <title>Using an Active Switch with TeleMega</title>
1403 As explained above, an external active switch requires three
1404 connections, one to the positive battery terminal, one to
1405 the flight computer positive input and one to ground.
1408 The positive battery terminal is available on Top terminal
1409 1, the positive flight computer input is on Top terminal
1410 2. Ground is on Top terminal 3.
1415 <title>EasyMega</title>
1419 <imagedata fileref="easymega-v1.0-top.jpg" width="4.5in" scalefit="1"/>
1424 EasyMega is a 1¼ inch by 2¼ inch circuit board. It was
1425 designed to easily fit in a 38mm coupler. Like TeleMetrum,
1426 EasyMega has an accelerometer and so it must be mounted so that
1427 the board is aligned with the flight axis. It can be mounted
1428 either antenna up or down.
1431 <title>EasyMega Screw Terminals</title>
1433 EasyMega has two sets of nine screw terminals on the end of
1434 the board opposite the telemetry antenna. They are as follows:
1437 <title>EasyMega Screw Terminals</title>
1438 <?dbfo keep-together="always"?>
1439 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
1440 <colspec align='center' colwidth='*' colname='Pin #'/>
1441 <colspec align='center' colwidth='2*' colname='Pin Name'/>
1442 <colspec align='left' colwidth='5*' colname='Description'/>
1445 <entry align='center'>Terminal #</entry>
1446 <entry align='center'>Terminal Name</entry>
1447 <entry align='center'>Description</entry>
1452 <entry>Top 1</entry>
1453 <entry>Switch Input</entry>
1454 <entry>Switch connection to positive battery terminal</entry>
1457 <entry>Top 2</entry>
1458 <entry>Switch Output</entry>
1459 <entry>Switch connection to flight computer</entry>
1462 <entry>Top 3</entry>
1464 <entry>Ground connection for use with external active switch</entry>
1467 <entry>Top 4</entry>
1468 <entry>Main -</entry>
1469 <entry>Main pyro channel connection to pyro circuit</entry>
1472 <entry>Top 5</entry>
1473 <entry>Main +</entry>
1474 <entry>Main pyro channel common connection to battery +</entry>
1477 <entry>Top 6</entry>
1478 <entry>Apogee -</entry>
1479 <entry>Apogee pyro channel connection to pyro circuit</entry>
1482 <entry>Top 7</entry>
1483 <entry>Apogee +</entry>
1484 <entry>Apogee pyro channel common connection to battery +</entry>
1487 <entry>Top 8</entry>
1489 <entry>D pyro channel connection to pyro circuit</entry>
1492 <entry>Top 9</entry>
1494 <entry>D pyro channel common connection to battery +</entry>
1497 <entry>Bottom 1</entry>
1499 <entry>Ground connection for negative pyro battery terminal</entry>
1502 <entry>Bottom 2</entry>
1504 <entry>Positive pyro battery terminal</entry>
1507 <entry>Bottom 3</entry>
1510 Power switch output. Use to connect main battery to
1515 <entry>Bottom 4</entry>
1517 <entry>A pyro channel connection to pyro circuit</entry>
1520 <entry>Bottom 5</entry>
1522 <entry>A pyro channel common connection to battery +</entry>
1525 <entry>Bottom 6</entry>
1527 <entry>B pyro channel connection to pyro circuit</entry>
1530 <entry>Bottom 7</entry>
1532 <entry>B pyro channel common connection to battery +</entry>
1535 <entry>Bottom 8</entry>
1537 <entry>C pyro channel connection to pyro circuit</entry>
1540 <entry>Bottom 9</entry>
1542 <entry>C pyro channel common connection to battery +</entry>
1549 <title>Using a Separate Pyro Battery with EasyMega</title>
1551 EasyMega provides explicit support for an external pyro
1552 battery. All that is required is to remove the jumper
1553 between the lipo terminal (Bottom 3) and the pyro terminal
1554 (Bottom 2). Then hook the negative pyro battery terminal to ground
1555 (Bottom 1) and the positive pyro battery to the pyro battery
1556 input (Bottom 2). You can then use the existing pyro screw
1557 terminals to hook up all of the pyro charges.
1561 <title>Using Only One Battery With EasyMega</title>
1563 Because EasyMega has built-in support for a separate pyro
1564 battery, if you want to fly with just one battery running
1565 both the computer and firing the charges, you need to
1566 connect the flight computer battery to the pyro
1567 circuit. EasyMega has two screw terminals for this—hook a
1568 wire from the Lipo terminal (Bottom 3) to the Pyro terminal
1573 <title>Using an Active Switch with EasyMega</title>
1575 As explained above, an external active switch requires three
1576 connections, one to the positive battery terminal, one to
1577 the flight computer positive input and one to ground.
1580 The positive battery terminal is available on Top terminal
1581 1, the positive flight computer input is on Top terminal
1582 2. Ground is on Top terminal 3.
1587 <title>Flight Data Recording</title>
1589 Each flight computer logs data at 100 samples per second
1590 during ascent and 10 samples per second during descent, except
1591 for TeleMini v1.0, which records ascent at 10 samples per
1592 second and descent at 1 sample per second. Data are logged to
1593 an on-board flash memory part, which can be partitioned into
1594 several equal-sized blocks, one for each flight.
1597 <title>Data Storage on Altus Metrum altimeters</title>
1598 <?dbfo keep-together="always"?>
1599 <tgroup cols='4' align='center' colsep='1' rowsep='1'>
1600 <colspec align='center' colwidth='*' colname='Device'/>
1601 <colspec align='center' colwidth='*' colname='Bytes per sample'/>
1602 <colspec align='center' colwidth='*' colname='Total storage'/>
1603 <colspec align='center' colwidth='*' colname='Minutes of
1607 <entry align='center'>Device</entry>
1608 <entry align='center'>Bytes per Sample</entry>
1609 <entry align='center'>Total Storage</entry>
1610 <entry align='center'>Minutes at Full Rate</entry>
1615 <entry>TeleMetrum v1.0</entry>
1621 <entry>TeleMetrum v1.1 v1.2</entry>
1627 <entry>TeleMetrum v2.0</entry>
1633 <entry>TeleMini v1.0</entry>
1639 <entry>TeleMini v2.0</entry>
1645 <entry>EasyMini</entry>
1651 <entry>TeleMega</entry>
1657 <entry>EasyMega</entry>
1666 The on-board flash is partitioned into separate flight logs,
1667 each of a fixed maximum size. Increase the maximum size of
1668 each log and you reduce the number of flights that can be
1669 stored. Decrease the size and you can store more flights.
1672 Configuration data is also stored in the flash memory on
1673 TeleMetrum v1.x, TeleMini and EasyMini. This consumes 64kB
1674 of flash space. This configuration space is not available
1675 for storing flight log data. TeleMetrum v2.0, TeleMega and EasyMega
1676 store configuration data in a bit of eeprom available within
1677 the processor chip, leaving that space available in flash for
1681 To compute the amount of space needed for a single flight, you
1682 can multiply the expected ascent time (in seconds) by 100
1683 times bytes-per-sample, multiply the expected descent time (in
1684 seconds) by 10 times the bytes per sample and add the two
1685 together. That will slightly under-estimate the storage (in
1686 bytes) needed for the flight. For instance, a TeleMetrum v2.0 flight spending
1687 20 seconds in ascent and 150 seconds in descent will take
1688 about (20 * 1600) + (150 * 160) = 56000 bytes of storage. You
1689 could store dozens of these flights in the on-board flash.
1692 The default size allows for several flights on each flight
1693 computer, except for TeleMini v1.0, which only holds data for a
1694 single flight. You can adjust the size.
1697 Altus Metrum flight computers will not overwrite existing
1698 flight data, so be sure to download flight data and erase it
1699 from the flight computer before it fills up. The flight
1700 computer will still successfully control the flight even if it
1701 cannot log data, so the only thing you will lose is the data.
1705 <title>Installation</title>
1707 A typical installation involves attaching
1708 only a suitable battery, a single pole switch for
1709 power on/off, and two pairs of wires connecting e-matches for the
1710 apogee and main ejection charges. All Altus Metrum products are
1711 designed for use with single-cell batteries with 3.7 volts
1712 nominal. TeleMini v2.0 and EasyMini may also be used with other
1713 batteries as long as they supply between 4 and 12 volts.
1716 The battery connectors are a standard 2-pin JST connector and
1717 match batteries sold by Spark Fun. These batteries are
1718 single-cell Lithium Polymer batteries that nominally provide 3.7
1719 volts. Other vendors sell similar batteries for RC aircraft
1720 using mating connectors, however the polarity for those is
1721 generally reversed from the batteries used by Altus Metrum
1722 products. In particular, the Tenergy batteries supplied for use
1723 in Featherweight flight computers are not compatible with Altus
1724 Metrum flight computers or battery chargers. <emphasis>Check
1725 polarity and voltage before connecting any battery not purchased
1726 from Altus Metrum or Spark Fun.</emphasis>
1729 By default, we use the unregulated output of the battery directly
1730 to fire ejection charges. This works marvelously with standard
1731 low-current e-matches like the J-Tek from MJG Technologies, and with
1732 Quest Q2G2 igniters. However, if you want or need to use a separate
1733 pyro battery, check out the “External Pyro Battery” section in this
1734 manual for instructions on how to wire that up. The altimeters are
1735 designed to work with an external pyro battery of no more than 15 volts.
1738 Ejection charges are wired directly to the screw terminal block
1739 at the aft end of the altimeter. You'll need a very small straight
1740 blade screwdriver for these screws, such as you might find in a
1741 jeweler's screwdriver set.
1744 Except for TeleMini v1.0, the flight computers also use the
1745 screw terminal block for the power switch leads. On TeleMini v1.0,
1746 the power switch leads are soldered directly to the board and
1747 can be connected directly to a switch.
1750 For most air-frames, the integrated antennas are more than
1751 adequate. However, if you are installing in a carbon-fiber or
1752 metal electronics bay which is opaque to RF signals, you may need to
1753 use off-board external antennas instead. In this case, you can
1754 replace the stock UHF antenna wire with an edge-launched SMA connector,
1755 and, on TeleMetrum v1, you can unplug the integrated GPS
1756 antenna and select an appropriate off-board GPS antenna with
1757 cable terminating in a U.FL connector.
1762 <title>System Operation</title>
1764 <title>Firmware Modes </title>
1766 The AltOS firmware build for the altimeters has two
1767 fundamental modes, “idle” and “flight”. Which of these modes
1768 the firmware operates in is determined at start up time. For
1769 TeleMetrum, TeleMega and EasyMega, which have accelerometers, the mode is
1770 controlled by the orientation of the
1771 rocket (well, actually the board, of course...) at the time
1772 power is switched on. If the rocket is “nose up”, then
1773 the flight computer assumes it's on a rail or rod being prepared for
1774 launch, so the firmware chooses flight mode. However, if the
1775 rocket is more or less horizontal, the firmware instead enters
1776 idle mode. Since TeleMini v2.0 and EasyMini don't have an
1777 accelerometer we can use to determine orientation, “idle” mode
1778 is selected if the board is connected via USB to a computer,
1779 otherwise the board enters “flight” mode. TeleMini v1.0
1780 selects “idle” mode if it receives a command packet within the
1781 first five seconds of operation.
1784 At power on, the altimeter will beep out the battery voltage
1785 to the nearest tenth of a volt. Each digit is represented by
1786 a sequence of short “dit” beeps, with a pause between
1787 digits. A zero digit is represented with one long “dah”
1788 beep. Then there will be a short pause while the altimeter
1789 completes initialization and self test, and decides which mode
1793 Here's a short summary of all of the modes and the beeping (or
1794 flashing, in the case of TeleMini v1) that accompanies each
1795 mode. In the description of the beeping pattern, “dit” means a
1796 short beep while "dah" means a long beep (three times as
1797 long). “Brap” means a long dissonant tone.
1799 <title>AltOS Modes</title>
1800 <?dbfo keep-together="always"?>
1801 <tgroup cols='4' align='center' colsep='1' rowsep='1'>
1802 <colspec align='center' colwidth='*' colname='Mode Name'/>
1803 <colspec align='center' colwidth='*' colname='Letter'/>
1804 <colspec align='center' colwidth='*' colname='Beeps'/>
1805 <colspec align='center' colwidth='*' colname='Description'/>
1808 <entry>Mode Name</entry>
1809 <entry>Abbreviation</entry>
1810 <entry>Beeps</entry>
1811 <entry>Description</entry>
1816 <entry>Startup</entry>
1818 <entry>battery voltage in decivolts</entry>
1821 Calibrating sensors, detecting orientation.
1828 <entry>dit dit</entry>
1831 Ready to accept commands over USB or radio link.
1838 <entry>dit dah dah dit</entry>
1841 Waiting for launch. Not listening for commands.
1846 <entry>Boost</entry>
1848 <entry>dah dit dit dit</entry>
1851 Accelerating upwards.
1858 <entry>dit dit dah dit</entry>
1861 Decelerating, but moving faster than 200m/s.
1866 <entry>Coast</entry>
1868 <entry>dah dit dah dit</entry>
1871 Decelerating, moving slower than 200m/s
1876 <entry>Drogue</entry>
1878 <entry>dah dit dit</entry>
1881 Descending after apogee. Above main height.
1888 <entry>dah dah</entry>
1891 Descending. Below main height.
1896 <entry>Landed</entry>
1898 <entry>dit dah dit dit</entry>
1901 Stable altitude for at least ten seconds.
1906 <entry>Sensor error</entry>
1908 <entry>dah dit dit dah</entry>
1911 Error detected during sensor calibration.
1920 In flight or “pad” mode, the altimeter engages the flight
1921 state machine, goes into transmit-only mode to send telemetry,
1922 and waits for launch to be detected. Flight mode is indicated
1923 by an “di-dah-dah-dit” (“P” for pad) on the beeper or lights,
1924 followed by beeps or flashes indicating the state of the
1925 pyrotechnic igniter continuity. One beep/flash indicates
1926 apogee continuity, two beeps/flashes indicate main continuity,
1927 three beeps/flashes indicate both apogee and main continuity,
1928 and one longer “brap” sound which is made by rapidly
1929 alternating between two tones indicates no continuity. For a
1930 dual deploy flight, make sure you're getting three beeps or
1931 flashes before launching! For apogee-only or motor eject
1932 flights, do what makes sense.
1935 If idle mode is entered, you will hear an audible “di-dit” or
1936 see two short flashes (“I” for idle), and the flight state
1937 machine is disengaged, thus no ejection charges will fire.
1938 The altimeters also listen for the radio link when in idle
1939 mode for requests sent via TeleDongle. Commands can be issued
1940 in idle mode over either USB or the radio link
1941 equivalently. TeleMini v1.0 only has the radio link. Idle
1942 mode is useful for configuring the altimeter, for extracting
1943 data from the on-board storage chip after flight, and for
1944 ground testing pyro charges.
1947 In “Idle” and “Pad” modes, once the mode indication
1948 beeps/flashes and continuity indication has been sent, if
1949 there is no space available to log the flight in on-board
1950 memory, the flight computer will emit a warbling tone (much
1951 slower than the “no continuity tone”)
1954 Here's a summary of all of the “pad” and “idle” mode indications.
1956 <title>Pad/Idle Indications</title>
1957 <?dbfo keep-together="always"?>
1958 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
1959 <colspec align='center' colwidth='*' colname='Name'/>
1960 <colspec align='center' colwidth='*' colname='Beeps'/>
1961 <colspec align='center' colwidth='*' colname='Description'/>
1965 <entry>Beeps</entry>
1966 <entry>Description</entry>
1971 <entry>Neither</entry>
1975 No continuity detected on either apogee or main
1981 <entry>Apogee</entry>
1985 Continuity detected only on apogee igniter.
1991 <entry>dit dit</entry>
1994 Continuity detected only on main igniter.
2000 <entry>dit dit dit</entry>
2003 Continuity detected on both igniters.
2008 <entry>Storage Full</entry>
2009 <entry>warble</entry>
2012 On-board data logging storage is full. This will
2013 not prevent the flight computer from safely
2014 controlling the flight or transmitting telemetry
2015 signals, but no record of the flight will be
2016 stored in on-board flash.
2025 Once landed, the flight computer will signal that by emitting
2026 the “Landed” sound described above, after which it will beep
2027 out the apogee height (in meters). Each digit is represented
2028 by a sequence of short “dit” beeps, with a pause between
2029 digits. A zero digit is represented with one long “dah”
2030 beep. The flight computer will continue to report landed mode
2031 and beep out the maximum height until turned off.
2034 One “neat trick” of particular value when TeleMetrum, TeleMega
2035 or EasyMega are used with
2036 very large air-frames, is that you can power the board up while the
2037 rocket is horizontal, such that it comes up in idle mode. Then you can
2038 raise the air-frame to launch position, and issue a 'reset' command
2039 via TeleDongle over the radio link to cause the altimeter to reboot and
2040 come up in flight mode. This is much safer than standing on the top
2041 step of a rickety step-ladder or hanging off the side of a launch
2042 tower with a screw-driver trying to turn on your avionics before
2043 installing igniters!
2046 TeleMini v1.0 is configured solely via the radio link. Of course, that
2047 means you need to know the TeleMini radio configuration values
2048 or you won't be able to communicate with it. For situations
2049 when you don't have the radio configuration values, TeleMini v1.0
2050 offers an 'emergency recovery' mode. In this mode, TeleMini is
2051 configured as follows:
2055 Sets the radio frequency to 434.550MHz
2060 Sets the radio calibration back to the factory value.
2065 Sets the callsign to N0CALL
2070 Does not go to 'pad' mode after five seconds.
2076 To get into 'emergency recovery' mode, first find the row of
2077 four small holes opposite the switch wiring. Using a short
2078 piece of small gauge wire, connect the outer two holes
2079 together, then power TeleMini up. Once the red LED is lit,
2080 disconnect the wire and the board should signal that it's in
2081 'idle' mode after the initial five second startup period.
2087 TeleMetrum and TeleMega include a complete GPS receiver. A
2088 complete explanation of how GPS works is beyond the scope of
2089 this manual, but the bottom line is that the GPS receiver
2090 needs to lock onto at least four satellites to obtain a solid
2091 3 dimensional position fix and know what time it is.
2094 The flight computers provide backup power to the GPS chip any time a
2095 battery is connected. This allows the receiver to “warm start” on
2096 the launch rail much faster than if every power-on were a GPS
2097 “cold start”. In typical operations, powering up
2098 on the flight line in idle mode while performing final air-frame
2099 preparation will be sufficient to allow the GPS receiver to cold
2100 start and acquire lock. Then the board can be powered down during
2101 RSO review and installation on a launch rod or rail. When the board
2102 is turned back on, the GPS system should lock very quickly, typically
2103 long before igniter installation and return to the flight line are
2108 <title>Controlling An Altimeter Over The Radio Link</title>
2110 One of the unique features of the Altus Metrum system is the
2111 ability to create a two way command link between TeleDongle
2112 and an altimeter using the digital radio transceivers
2113 built into each device. This allows you to interact with the
2114 altimeter from afar, as if it were directly connected to the
2118 Any operation which can be performed with a flight computer can
2119 either be done with the device directly connected to the
2120 computer via the USB cable, or through the radio
2121 link. TeleMini v1.0 doesn't provide a USB connector and so it is
2122 always communicated with over radio. Select the appropriate
2123 TeleDongle device when the list of devices is presented and
2124 AltosUI will interact with an altimeter over the radio link.
2127 One oddity in the current interface is how AltosUI selects the
2128 frequency for radio communications. Instead of providing
2129 an interface to specifically configure the frequency, it uses
2130 whatever frequency was most recently selected for the target
2131 TeleDongle device in Monitor Flight mode. If you haven't ever
2132 used that mode with the TeleDongle in question, select the
2133 Monitor Flight button from the top level UI, and pick the
2134 appropriate TeleDongle device. Once the flight monitoring
2135 window is open, select the desired frequency and then close it
2136 down again. All radio communications will now use that frequency.
2141 Save Flight Data—Recover flight data from the rocket without
2147 Configure altimeter apogee delays, main deploy heights
2148 and additional pyro event conditions
2149 to respond to changing launch conditions. You can also
2150 'reboot' the altimeter. Use this to remotely enable the
2151 flight computer by turning TeleMetrum or TeleMega on in “idle” mode,
2152 then once the air-frame is oriented for launch, you can
2153 reboot the altimeter and have it restart in pad mode
2154 without having to climb the scary ladder.
2159 Fire Igniters—Test your deployment charges without snaking
2160 wires out through holes in the air-frame. Simply assemble the
2161 rocket as if for flight with the apogee and main charges
2162 loaded, then remotely command the altimeter to fire the
2168 Operation over the radio link for configuring an altimeter, ground
2169 testing igniters, and so forth uses the same RF frequencies as flight
2170 telemetry. To configure the desired TeleDongle frequency, select
2171 the monitor flight tab, then use the frequency selector and
2172 close the window before performing other desired radio operations.
2175 The flight computers only enable radio commanding in 'idle' mode.
2176 TeleMetrum and TeleMega use the accelerometer to detect which orientation they
2177 start up in, so make sure you have the flight computer lying horizontally when you turn
2178 it on. Otherwise, it will start in 'pad' mode ready for
2179 flight, and will not be listening for command packets from TeleDongle.
2182 TeleMini listens for a command packet for five seconds after
2183 first being turned on, if it doesn't hear anything, it enters
2184 'pad' mode, ready for flight and will no longer listen for
2185 command packets. The easiest way to connect to TeleMini is to
2186 initiate the command and select the TeleDongle device. At this
2187 point, the TeleDongle will be attempting to communicate with
2188 the TeleMini. Now turn TeleMini on, and it should immediately
2189 start communicating with the TeleDongle and the desired
2190 operation can be performed.
2193 You can monitor the operation of the radio link by watching the
2194 lights on the devices. The red LED will flash each time a packet
2195 is transmitted, while the green LED will light up on TeleDongle when
2196 it is waiting to receive a packet from the altimeter.
2200 <title>Ground Testing </title>
2202 An important aspect of preparing a rocket using electronic deployment
2203 for flight is ground testing the recovery system. Thanks
2204 to the bi-directional radio link central to the Altus Metrum system,
2205 this can be accomplished in a TeleMega, TeleMetrum or TeleMini equipped rocket
2206 with less work than you may be accustomed to with other systems. It
2210 Just prep the rocket for flight, then power up the altimeter
2211 in “idle” mode (placing air-frame horizontal for TeleMetrum or TeleMega, or
2212 selecting the Configure Altimeter tab for TeleMini). This will cause
2213 the firmware to go into “idle” mode, in which the normal flight
2214 state machine is disabled and charges will not fire without
2215 manual command. You can now command the altimeter to fire the apogee
2216 or main charges from a safe distance using your computer and
2217 TeleDongle and the Fire Igniter tab to complete ejection testing.
2221 <title>Radio Link </title>
2223 Our flight computers all incorporate an RF transceiver, but
2224 it's not a full duplex system... each end can only be transmitting or
2225 receiving at any given moment. So we had to decide how to manage the
2229 By design, the altimeter firmware listens for the radio link when
2230 it's in “idle mode”, which
2231 allows us to use the radio link to configure the rocket, do things like
2232 ejection tests, and extract data after a flight without having to
2233 crack open the air-frame. However, when the board is in “flight
2234 mode”, the altimeter only
2235 transmits and doesn't listen at all. That's because we want to put
2236 ultimate priority on event detection and getting telemetry out of
2238 the radio in case the rocket crashes and we aren't able to extract
2242 We don't generally use a 'normal packet radio' mode like APRS
2243 because they're just too inefficient. The GFSK modulation we
2244 use is FSK with the base-band pulses passed through a Gaussian
2245 filter before they go into the modulator to limit the
2246 transmitted bandwidth. When combined with forward error
2247 correction and interleaving, this allows us to have a very
2248 robust 19.2 kilobit data link with only 10-40 milliwatts of
2249 transmit power, a whip antenna in the rocket, and a hand-held
2250 Yagi on the ground. We've had flights to above 21k feet AGL
2251 with great reception, and calculations suggest we should be
2252 good to well over 40k feet AGL with a 5-element yagi on the
2253 ground with our 10mW units and over 100k feet AGL with the
2254 40mW devices. We hope to fly boards to higher altitudes over
2255 time, and would of course appreciate customer feedback on
2256 performance in higher altitude flights!
2262 TeleMetrum v2.0 and TeleMega can send APRS if desired, and the
2263 interval between APRS packets can be configured. As each APRS
2264 packet takes a full second to transmit, we recommend an
2265 interval of at least 5 seconds to avoid consuming too much
2266 battery power or radio channel bandwidth. You can configure
2267 the APRS interval using AltosUI; that process is described in
2268 the Configure Altimeter section of the AltosUI chapter.
2271 AltOS uses the APRS compressed position report data format,
2272 which provides for higher position precision and shorter
2273 packets than the original APRS format. It also includes
2274 altitude data, which is invaluable when tracking rockets. We
2275 haven't found a receiver which doesn't handle compressed
2276 positions, but it's just possible that you have one, so if you
2277 have an older device that can receive the raw packets but
2278 isn't displaying position information, it's possible that this
2282 APRS packets include an SSID (Secondary Station Identifier)
2283 field that allows one operator to have multiple
2284 transmitters. AltOS allows you to set this to a single digit
2285 from 0 to 9, allowing you to fly multiple transmitters at the
2286 same time while keeping the identify of each one separate in
2287 the receiver. By default, the SSID is set to the last digit of
2288 the device serial number.
2291 The APRS packet format includes a comment field that can have
2292 arbitrary text in it. AltOS uses this to send status
2293 information about the flight computer. It sends four fields as
2294 shown in the following table.
2297 <title>Altus Metrum APRS Comments</title>
2298 <?dbfo keep-together="always"?>
2299 <tgroup cols='3' align='center' colsep='1' rowsep='1'>
2300 <colspec align='center' colwidth='*' colname='Field'/>
2301 <colspec align='center' colwidth='*' colname='Example'/>
2302 <colspec align='center' colwidth='4*' colname='Description'/>
2305 <entry align='center'>Field</entry>
2306 <entry align='center'>Example</entry>
2307 <entry align='center'>Description</entry>
2314 <entry>GPS Status U for unlocked, L for locked</entry>
2319 <entry>Number of Satellites in View</entry>
2324 <entry>Altimeter Battery Voltage</entry>
2329 <entry>Apogee Igniter Voltage</entry>
2334 <entry>Main Igniter Voltage</entry>
2339 <entry>Device Serial Number</entry>
2345 Here's an example of an APRS comment showing GPS lock with 6
2346 satellites in view, a primary battery at 4.0V, and
2347 apogee and main igniters both at 3.7V from device 1286.
2349 L6 B4.0 A3.7 M3.7 1286
2353 Make sure your primary battery is above 3.8V, any connected
2354 igniters are above 3.5V and GPS is locked with at least 5 or 6
2355 satellites in view before flying. If GPS is switching between
2356 L and U regularly, then it doesn't have a good lock and you
2357 should wait until it becomes stable.
2360 If the GPS receiver loses lock, the APRS data transmitted will
2361 contain the last position for which GPS lock was
2362 available. You can tell that this has happened by noticing
2363 that the GPS status character switches from 'L' to 'U'. Before
2364 GPS has locked, APRS will transmit zero for latitude,
2365 longitude and altitude.
2369 <title>Configurable Parameters</title>
2371 Configuring an Altus Metrum altimeter for flight is very
2372 simple. Even on our baro-only TeleMini and EasyMini boards,
2373 the use of a Kalman filter means there is no need to set a
2374 “mach delay”. The few configurable parameters can all be set
2375 using AltosUI over USB or or radio link via TeleDongle. Read
2376 the Configure Altimeter section in the AltosUI chapter below
2377 for more information.
2380 <title>Radio Frequency</title>
2382 Altus Metrum boards support radio frequencies in the 70cm
2383 band. By default, the configuration interface provides a
2384 list of 10 “standard” frequencies in 100kHz channels starting at
2385 434.550MHz. However, the firmware supports use of
2386 any 50kHz multiple within the 70cm band. At any given
2387 launch, we highly recommend coordinating when and by whom each
2388 frequency will be used to avoid interference. And of course, both
2389 altimeter and TeleDongle must be configured to the same
2390 frequency to successfully communicate with each other.
2394 <title>Callsign</title>
2396 This sets the callsign used for telemetry, APRS and the
2397 packet link. For telemetry and APRS, this is used to
2398 identify the device. For the packet link, the callsign must
2399 match that configured in AltosUI or the link will not
2400 work. This is to prevent accidental configuration of another
2401 Altus Metrum flight computer operating on the same frequency nearby.
2405 <title>Telemetry/RDF/APRS Enable</title>
2407 You can completely disable the radio while in flight, if
2408 necessary. This doesn't disable the packet link in idle
2413 <title>Telemetry baud rate</title>
2415 This sets the modulation bit rate for data transmission for
2416 both telemetry and packet link mode. Lower bit
2417 rates will increase range while reducing the amount of data
2418 that can be sent and increasing battery consumption. All
2419 telemetry is done using a rate 1/2 constraint 4 convolution
2420 code, so the actual data transmission rate is 1/2 of the
2421 modulation bit rate specified here.
2425 <title>APRS Interval</title>
2427 This selects how often APRS packets are transmitted. Set
2428 this to zero to disable APRS without also disabling the
2429 regular telemetry and RDF transmissions. As APRS takes a
2430 full second to transmit a single position report, we
2431 recommend sending packets no more than once every 5 seconds.
2435 <title>APRS SSID</title>
2437 This selects the SSID reported in APRS packets. By default,
2438 it is set to the last digit of the serial number, but you
2439 can change this to any value from 0 to 9.
2443 <title>Apogee Delay</title>
2445 Apogee delay is the number of seconds after the altimeter detects flight
2446 apogee that the drogue charge should be fired. In most cases, this
2447 should be left at the default of 0. However, if you are flying
2448 redundant electronics such as for an L3 certification, you may wish
2449 to set one of your altimeters to a positive delay so that both
2450 primary and backup pyrotechnic charges do not fire simultaneously.
2453 The Altus Metrum apogee detection algorithm fires exactly at
2454 apogee. If you are also flying an altimeter like the
2455 PerfectFlite MAWD, which only supports selecting 0 or 1
2456 seconds of apogee delay, you may wish to set the MAWD to 0
2457 seconds delay and set the TeleMetrum to fire your backup 2
2458 or 3 seconds later to avoid any chance of both charges
2459 firing simultaneously. We've flown several air-frames this
2460 way quite happily, including Keith's successful L3 cert.
2464 <title>Apogee Lockout</title>
2466 Apogee lockout is the number of seconds after boost where
2467 the flight computer will not fire the apogee charge, even if
2468 the rocket appears to be at apogee. This is often called
2469 'Mach Delay', as it is intended to prevent a flight computer
2470 from unintentionally firing apogee charges due to the pressure
2471 spike that occurrs across a mach transition. Altus Metrum
2472 flight computers include a Kalman filter which is not fooled
2473 by this sharp pressure increase, and so this setting should
2474 be left at the default value of zero to disable it.
2478 <title>Main Deployment Altitude</title>
2480 By default, the altimeter will fire the main deployment charge at an
2481 elevation of 250 meters (about 820 feet) above ground. We think this
2482 is a good elevation for most air-frames, but feel free to change this
2483 to suit. In particular, if you are flying two altimeters, you may
2485 deployment elevation for the backup altimeter to be something lower
2486 than the primary so that both pyrotechnic charges don't fire
2491 <title>Maximum Flight Log</title>
2493 Changing this value will set the maximum amount of flight
2494 log storage that an individual flight will use. The
2495 available storage is divided into as many flights of the
2496 specified size as can fit in the available space. You can
2497 download and erase individual flight logs. If you fill up
2498 the available storage, future flights will not get logged
2499 until you erase some of the stored ones.
2502 Even though our flight computers (except TeleMini v1.0) can store
2503 multiple flights, we strongly recommend downloading and saving
2504 flight data after each flight.
2508 <title>Ignite Mode</title>
2510 Instead of firing one charge at apogee and another charge at
2511 a fixed height above the ground, you can configure the
2512 altimeter to fire both at apogee or both during
2513 descent. This was added to support an airframe Bdale designed that
2514 had two altimeters, one in the fin can and one in the nose.
2517 Providing the ability to use both igniters for apogee or
2518 main allows some level of redundancy without needing two
2519 flight computers. In Redundant Apogee or Redundant Main
2520 mode, the two charges will be fired two seconds apart.
2524 <title>Pad Orientation</title>
2526 TeleMetrum, TeleMega and EasyMega measure acceleration along the axis
2527 of the board. Which way the board is oriented affects the
2528 sign of the acceleration value. Instead of trying to guess
2529 which way the board is mounted in the air frame, the
2530 altimeter must be explicitly configured for either Antenna
2531 Up or Antenna Down. The default, Antenna Up, expects the end
2532 of the board connected to the 70cm antenna to be nearest the
2533 nose of the rocket, with the end containing the screw
2534 terminals nearest the tail.
2538 <title>Configurable Pyro Channels</title>
2540 In addition to the usual Apogee and Main pyro channels,
2541 TeleMega and EasyMega have four additional channels that can be configured
2542 to activate when various flight conditions are
2543 satisfied. You can select as many conditions as necessary;
2544 all of them must be met in order to activate the
2545 channel. The conditions available are:
2550 Acceleration away from the ground. Select a value, and
2551 then choose whether acceleration should be above or
2552 below that value. Acceleration is positive upwards, so
2553 accelerating towards the ground would produce negative
2554 numbers. Acceleration during descent is noisy and
2555 inaccurate, so be careful when using it during these
2556 phases of the flight.
2561 Vertical speed. Select a value, and then choose whether
2562 vertical speed should be above or below that
2563 value. Speed is positive upwards, so moving towards the
2564 ground would produce negative numbers. Speed during
2565 descent is a bit noisy and so be careful when using it
2566 during these phases of the flight.
2571 Height. Select a value, and then choose whether the
2572 height above the launch pad should be above or below
2578 Orientation. TeleMega and EasyMega contain a 3-axis gyroscope and
2579 accelerometer which is used to measure the current
2580 angle. Note that this angle is not the change in angle
2581 from the launch pad, but rather absolute relative to
2582 gravity; the 3-axis accelerometer is used to compute the
2583 angle of the rocket on the launch pad and initialize the
2584 system. Because this value is computed by integrating
2585 rate gyros, it gets progressively less accurate as the
2586 flight goes on. It should have an accumulated error of
2587 less than 0.2°/second (after 10 seconds of flight, the
2588 error should be less than 2°).
2591 The usual use of the orientation configuration is to
2592 ensure that the rocket is traveling mostly upwards when
2593 deciding whether to ignite air starts or additional
2594 stages. For that, choose a reasonable maximum angle
2595 (like 20°) and set the motor igniter to require an angle
2596 of less than that value.
2601 Flight Time. Time since boost was detected. Select a
2602 value and choose whether to activate the pyro channel
2603 before or after that amount of time.
2608 Ascending. A simple test saying whether the rocket is
2609 going up or not. This is exactly equivalent to testing
2610 whether the speed is > 0.
2615 Descending. A simple test saying whether the rocket is
2616 going down or not. This is exactly equivalent to testing
2617 whether the speed is < 0.
2622 After Motor. The flight software counts each time the
2623 rocket starts accelerating (presumably due to a motor or
2624 motors igniting). Use this value to count ignitions for
2625 multi-staged or multi-airstart launches.
2630 Delay. This value doesn't perform any checks, instead it
2631 inserts a delay between the time when the other
2632 parameters become true and when the pyro channel is
2638 Flight State. The flight software tracks the flight
2639 through a sequence of states:
2643 Boost. The motor has lit and the rocket is
2644 accelerating upwards.
2649 Fast. The motor has burned out and the rocket is
2650 decelerating, but it is going faster than 200m/s.
2655 Coast. The rocket is still moving upwards and
2656 decelerating, but the speed is less than 200m/s.
2661 Drogue. The rocket has reached apogee and is heading
2662 back down, but is above the configured Main
2668 Main. The rocket is still descending, and is below
2674 Landed. The rocket is no longer moving.
2680 You can select a state to limit when the pyro channel
2681 may activate; note that the check is based on when the
2682 rocket transitions <emphasis>into</emphasis> the state, and so checking for
2683 “greater than Boost” means that the rocket is currently
2684 in boost or some later state.
2687 When a motor burns out, the rocket enters either Fast or
2688 Coast state (depending on how fast it is moving). If the
2689 computer detects upwards acceleration again, it will
2690 move back to Boost state.
2699 <title>AltosUI</title>
2703 <imagedata fileref="altosui.png" width="4.6in"/>
2708 The AltosUI program provides a graphical user interface for
2709 interacting with the Altus Metrum product family. AltosUI can
2710 monitor telemetry data, configure devices and many other
2711 tasks. The primary interface window provides a selection of
2712 buttons, one for each major activity in the system. This chapter
2713 is split into sections, each of which documents one of the tasks
2714 provided from the top-level toolbar.
2717 <title>Monitor Flight</title>
2718 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
2720 Selecting this item brings up a dialog box listing all of the
2721 connected TeleDongle devices. When you choose one of these,
2722 AltosUI will create a window to display telemetry data as
2723 received by the selected TeleDongle device.
2728 <imagedata fileref="device-selection.png" width="3.1in"/>
2733 All telemetry data received are automatically recorded in
2734 suitable log files. The name of the files includes the current
2735 date and rocket serial and flight numbers.
2738 The radio frequency being monitored by the TeleDongle device is
2739 displayed at the top of the window. You can configure the
2740 frequency by clicking on the frequency box and selecting the desired
2741 frequency. AltosUI remembers the last frequency selected for each
2742 TeleDongle and selects that automatically the next time you use
2746 Below the TeleDongle frequency selector, the window contains a few
2747 significant pieces of information about the altimeter providing
2748 the telemetry data stream:
2752 <para>The configured call-sign</para>
2755 <para>The device serial number</para>
2758 <para>The flight number. Each altimeter remembers how many
2764 The rocket flight state. Each flight passes through several
2765 states including Pad, Boost, Fast, Coast, Drogue, Main and
2771 The Received Signal Strength Indicator value. This lets
2772 you know how strong a signal TeleDongle is receiving. At
2773 the default data rate, 38400 bps, in bench testing, the
2774 radio inside TeleDongle v0.2 operates down to about
2775 -106dBm, while the v3 radio works down to about -111dBm.
2776 Weaker signals, or an environment with radio noise may
2777 cause the data to not be received. The packet link uses
2778 error detection and correction techniques which prevent
2779 incorrect data from being reported.
2784 The age of the displayed data, in seconds since the last
2785 successfully received telemetry packet. In normal operation
2786 this will stay in the low single digits. If the number starts
2787 counting up, then you are no longer receiving data over the radio
2788 link from the flight computer.
2793 Finally, the largest portion of the window contains a set of
2794 tabs, each of which contain some information about the rocket.
2795 They're arranged in 'flight order' so that as the flight
2796 progresses, the selected tab automatically switches to display
2797 data relevant to the current state of the flight. You can select
2798 other tabs at any time. The final 'table' tab displays all of
2799 the raw telemetry values in one place in a spreadsheet-like format.
2802 <title>Launch Pad</title>
2806 <imagedata fileref="launch-pad.png" width="5.5in"/>
2811 The 'Launch Pad' tab shows information used to decide when the
2812 rocket is ready for flight. The first elements include red/green
2813 indicators, if any of these is red, you'll want to evaluate
2814 whether the rocket is ready to launch:
2817 <term>Battery Voltage</term>
2820 This indicates whether the Li-Po battery powering the
2821 flight computer has sufficient charge to last for
2822 the duration of the flight. A value of more than
2823 3.8V is required for a 'GO' status.
2828 <term>Apogee Igniter Voltage</term>
2831 This indicates whether the apogee
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>Main Igniter Voltage</term>
2843 This indicates whether the main
2844 igniter has continuity. If the igniter has a low
2845 resistance, then the voltage measured here will be close
2846 to the Li-Po battery voltage. A value greater than 3.2V is
2847 required for a 'GO' status.
2852 <term>On-board Data Logging</term>
2855 This indicates whether there is
2856 space remaining on-board to store flight data for the
2857 upcoming flight. If you've downloaded data, but failed
2858 to erase flights, there may not be any space
2859 left. Most of our flight computers can store multiple
2860 flights, depending on the configured maximum flight log
2861 size. TeleMini v1.0 stores only a single flight, so it
2863 downloaded and erased after each flight to capture
2864 data. This only affects on-board flight logging; the
2865 altimeter will still transmit telemetry and fire
2866 ejection charges at the proper times even if the flight
2867 data storage is full.
2872 <term>GPS Locked</term>
2875 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
2876 currently able to compute position information. GPS requires
2877 at least 4 satellites to compute an accurate position.
2882 <term>GPS Ready</term>
2885 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
2886 10 consecutive positions without losing lock. This ensures
2887 that the GPS receiver has reliable reception from the
2895 The Launchpad tab also shows the computed launch pad position
2896 and altitude, averaging many reported positions to improve the
2897 accuracy of the fix.
2901 <title>Ascent</title>
2905 <imagedata fileref="ascent.png" width="5.5in"/>
2910 This tab is shown during Boost, Fast and Coast
2911 phases. The information displayed here helps monitor the
2912 rocket as it heads towards apogee.
2915 The height, speed, acceleration and tilt are shown along
2916 with the maximum values for each of them. This allows you to
2917 quickly answer the most commonly asked questions you'll hear
2921 The current latitude and longitude reported by the GPS are
2922 also shown. Note that under high acceleration, these values
2923 may not get updated as the GPS receiver loses position
2924 fix. Once the rocket starts coasting, the receiver should
2925 start reporting position again.
2928 Finally, the current igniter voltages are reported as in the
2929 Launch Pad tab. This can help diagnose deployment failures
2930 caused by wiring which comes loose under high acceleration.
2934 <title>Descent</title>
2938 <imagedata fileref="descent.png" width="5.5in"/>
2943 Once the rocket has reached apogee and (we hope) activated the
2944 apogee charge, attention switches to tracking the rocket on
2945 the way back to the ground, and for dual-deploy flights,
2946 waiting for the main charge to fire.
2949 To monitor whether the apogee charge operated correctly, the
2950 current descent rate is reported along with the current
2951 height. Good descent rates vary based on the choice of recovery
2952 components, but generally range from 15-30m/s on drogue and should
2953 be below 10m/s when under the main parachute in a dual-deploy flight.
2956 With GPS-equipped flight computers, you can locate the rocket in the
2957 sky using the elevation and bearing information to figure
2958 out where to look. Elevation is in degrees above the
2959 horizon. Bearing is reported in degrees relative to true
2960 north. Range can help figure out how big the rocket will
2961 appear. Ground Distance shows how far it is to a point
2962 directly under the rocket and can help figure out where the
2963 rocket is likely to land. Note that all of these values are
2964 relative to the pad location. If the elevation is near 90°,
2965 the rocket is over the pad, not over you.
2968 Finally, the igniter voltages are reported in this tab as
2969 well, both to monitor the main charge as well as to see what
2970 the status of the apogee charge is. Note that some commercial
2971 e-matches are designed to retain continuity even after being
2972 fired, and will continue to show as green or return from red to
2977 <title>Landed</title>
2981 <imagedata fileref="landed.png" width="5.5in"/>
2986 Once the rocket is on the ground, attention switches to
2987 recovery. While the radio signal is often lost once the
2988 rocket is on the ground, the last reported GPS position is
2989 generally within a short distance of the actual landing location.
2992 The last reported GPS position is reported both by
2993 latitude and longitude as well as a bearing and distance from
2994 the launch pad. The distance should give you a good idea of
2995 whether to walk or hitch a ride. Take the reported
2996 latitude and longitude and enter them into your hand-held GPS
2997 unit and have that compute a track to the landing location.
3000 Our flight computers will continue to transmit RDF
3001 tones after landing, allowing you to locate the rocket by
3002 following the radio signal if necessary. You may need to get
3003 away from the clutter of the flight line, or even get up on
3004 a hill (or your neighbor's RV roof) to receive the RDF signal.
3007 The maximum height, speed and acceleration reported
3008 during the flight are displayed for your admiring observers.
3009 The accuracy of these immediate values depends on the quality
3010 of your radio link and how many packets were received.
3011 Recovering the on-board data after flight may yield
3012 more precise results.
3015 To get more detailed information about the flight, you can
3016 click on the 'Graph Flight' button which will bring up a
3017 graph window for the current flight.
3021 <title>Table</title>
3025 <imagedata fileref="table.png" width="5.5in"/>
3030 The table view shows all of the data available from the
3031 flight computer. Probably the most useful data on
3032 this tab is the detailed GPS information, which includes
3033 horizontal dilution of precision information, and
3034 information about the signal being received from the satellites.
3038 <title>Site Map</title>
3042 <imagedata fileref="site-map.png" width="5.5in"/>
3047 When the TeleMetrum has a GPS fix, the Site Map tab will map
3048 the rocket's position to make it easier for you to locate the
3049 rocket, both while it is in the air, and when it has landed. The
3050 rocket's state is indicated by color: white for pad, red for
3051 boost, pink for fast, yellow for coast, light blue for drogue,
3052 dark blue for main, and black for landed.
3055 The map's default scale is approximately 3m (10ft) per pixel. The map
3056 can be dragged using the left mouse button. The map will attempt
3057 to keep the rocket roughly centered while data is being received.
3060 You can adjust the style of map and the zoom level with
3061 buttons on the right side of the map window. You can draw a
3062 line on the map by moving the mouse over the map with a
3063 button other than the left one pressed, or by pressing the
3064 left button while also holding down the shift key. The
3065 length of the line in real-world units will be shown at the
3069 Images are fetched automatically via the Google Maps Static API,
3070 and cached on disk for reuse. If map images cannot be downloaded,
3071 the rocket's path will be traced on a dark gray background
3075 You can pre-load images for your favorite launch sites
3076 before you leave home; check out the 'Preload Maps' section below.
3080 <title>Ignitor</title>
3084 <imagedata fileref="ignitor.png" width="5.5in"/>
3089 TeleMega includes four additional programmable pyro
3090 channels. The Ignitor tab shows whether each of them has
3091 continuity. If an ignitor has a low resistance, then the
3092 voltage measured here will be close to the pyro battery
3093 voltage. A value greater than 3.2V is required for a 'GO'
3099 <title>Save Flight Data</title>
3101 The altimeter records flight data to its internal flash memory.
3102 TeleMetrum data is recorded at a much higher rate than the telemetry
3103 system can handle, and is not subject to radio drop-outs. As
3104 such, it provides a more complete and precise record of the
3105 flight. The 'Save Flight Data' button allows you to read the
3106 flash memory and write it to disk.
3109 Clicking on the 'Save Flight Data' button brings up a list of
3110 connected flight computers and TeleDongle devices. If you select a
3111 flight computer, the flight data will be downloaded from that
3112 device directly. If you select a TeleDongle device, flight data
3113 will be downloaded from a flight computer over radio link via the
3114 specified TeleDongle. See the chapter on Controlling An Altimeter
3115 Over The Radio Link for more information.
3118 After the device has been selected, a dialog showing the
3119 flight data saved in the device will be shown allowing you to
3120 select which flights to download and which to delete. With
3121 version 0.9 or newer firmware, you must erase flights in order
3122 for the space they consume to be reused by another
3123 flight. This prevents accidentally losing flight data
3124 if you neglect to download data before flying again. Note that
3125 if there is no more space available in the device, then no
3126 data will be recorded during the next flight.
3129 The file name for each flight log is computed automatically
3130 from the recorded flight date, altimeter serial number and
3131 flight number information.
3135 <title>Replay Flight</title>
3137 Select this button and you are prompted to select a flight
3138 record file, either a .telem file recording telemetry data or a
3139 .eeprom file containing flight data saved from the altimeter
3143 Once a flight record is selected, the flight monitor interface
3144 is displayed and the flight is re-enacted in real time. Check
3145 the Monitor Flight chapter above to learn how this window operates.
3149 <title>Graph Data</title>
3151 Select this button and you are prompted to select a flight
3152 record file, either a .telem file recording telemetry data or a
3153 .eeprom file containing flight data saved from
3157 Note that telemetry files will generally produce poor graphs
3158 due to the lower sampling rate and missed telemetry packets.
3159 Use saved flight data in .eeprom files for graphing where possible.
3162 Once a flight record is selected, a window with multiple tabs is
3166 <title>Flight Graph</title>
3170 <imagedata fileref="graph.png" width="6in" scalefit="1"/>
3175 By default, the graph contains acceleration (blue),
3176 velocity (green) and altitude (red).
3179 The graph can be zoomed into a particular area by clicking and
3180 dragging down and to the right. Once zoomed, the graph can be
3181 reset by clicking and dragging up and to the left. Holding down
3182 control and clicking and dragging allows the graph to be panned.
3183 The right mouse button causes a pop-up menu to be displayed, giving
3184 you the option save or print the plot.
3188 <title>Configure Graph</title>
3192 <imagedata fileref="graph-configure.png" width="6in" scalefit="1"/>
3197 This selects which graph elements to show, and, at the
3198 very bottom, lets you switch between metric and
3203 <title>Flight Statistics</title>
3207 <imagedata fileref="graph-stats.png" width="6in" scalefit="1"/>
3212 Shows overall data computed from the flight.
3220 <imagedata fileref="graph-map.png" width="6in" scalefit="1"/>
3225 Shows a satellite image of the flight area overlaid
3226 with the path of the flight. The red concentric
3227 circles mark the launch pad, the black concentric
3228 circles mark the landing location.
3233 <title>Export Data</title>
3235 This tool takes the raw data files and makes them available for
3236 external analysis. When you select this button, you are prompted to
3237 select a flight data file, which can be either a .eeprom or .telem.
3238 The .eeprom files contain higher resolution and more continuous data,
3239 while .telem files contain receiver signal strength information.
3240 Next, a second dialog appears which is used to select
3241 where to write the resulting file. It has a selector to choose
3242 between CSV and KML file formats.
3245 <title>Comma Separated Value Format</title>
3247 This is a text file containing the data in a form suitable for
3248 import into a spreadsheet or other external data analysis
3249 tool. The first few lines of the file contain the version and
3250 configuration information from the altimeter, then
3251 there is a single header line which labels all of the
3252 fields. All of these lines start with a '#' character which
3253 many tools can be configured to skip over.
3256 The remaining lines of the file contain the data, with each
3257 field separated by a comma and at least one space. All of
3258 the sensor values are converted to standard units, with the
3259 barometric data reported in both pressure, altitude and
3260 height above pad units.
3264 <title>Keyhole Markup Language (for Google Earth)</title>
3266 This is the format used by Google Earth to provide an overlay
3267 within that application. With this, you can use Google Earth to
3268 see the whole flight path in 3D.
3273 <title>Configure Altimeter</title>
3277 <imagedata fileref="configure-altimeter.png" width="3.6in" scalefit="1"/>
3282 Select this button and then select either an altimeter or
3283 TeleDongle Device from the list provided. Selecting a TeleDongle
3284 device will use the radio link to configure a remote altimeter.
3287 The first few lines of the dialog provide information about the
3288 connected device, including the product name,
3289 software version and hardware serial number. Below that are the
3290 individual configuration entries.
3293 At the bottom of the dialog, there are four buttons:
3300 This writes any changes to the
3301 configuration parameter block in flash memory. If you don't
3302 press this button, any changes you make will be lost.
3310 This resets the dialog to the most recently saved values,
3311 erasing any changes you have made.
3319 This reboots the device. Use this to
3320 switch from idle to pad mode by rebooting once the rocket is
3321 oriented for flight, or to confirm changes you think you saved
3330 This closes the dialog. Any unsaved changes will be
3337 The rest of the dialog contains the parameters to be configured.
3340 <title>Main Deploy Altitude</title>
3342 This sets the altitude (above the recorded pad altitude) at
3343 which the 'main' igniter will fire. The drop-down menu shows
3344 some common values, but you can edit the text directly and
3345 choose whatever you like. If the apogee charge fires below
3346 this altitude, then the main charge will fire two seconds
3347 after the apogee charge fires.
3351 <title>Apogee Delay</title>
3353 When flying redundant electronics, it's often important to
3354 ensure that multiple apogee charges don't fire at precisely
3355 the same time, as that can over pressurize the apogee deployment
3356 bay and cause a structural failure of the air-frame. The Apogee
3357 Delay parameter tells the flight computer to fire the apogee
3358 charge a certain number of seconds after apogee has been
3363 <title>Apogee Lockoug</title>
3365 Apogee lockout is the number of seconds after boost where
3366 the flight computer will not fire the apogee charge, even if
3367 the rocket appears to be at apogee. This is often called
3368 'Mach Delay', as it is intended to prevent a flight computer
3369 from unintentionally firing apogee charges due to the pressure
3370 spike that occurrs across a mach transition. Altus Metrum
3371 flight computers include a Kalman filter which is not fooled
3372 by this sharp pressure increase, and so this setting should
3373 be left at the default value of zero to disable it.
3377 <title>Frequency</title>
3379 This configures which of the frequencies to use for both
3380 telemetry and packet command mode. Note that if you set this
3381 value via packet command mode, the TeleDongle frequency will
3382 also be automatically reconfigured to match so that
3383 communication will continue afterwards.
3387 <title>RF Calibration</title>
3389 The radios in every Altus Metrum device are calibrated at the
3390 factory to ensure that they transmit and receive on the
3391 specified frequency. If you need to you can adjust the calibration
3392 by changing this value. Do not do this without understanding what
3393 the value means, read the appendix on calibration and/or the source
3394 code for more information. To change a TeleDongle's calibration,
3395 you must reprogram the unit completely.
3399 <title>Telemetry/RDF/APRS Enable</title>
3401 Enables the radio for transmission during flight. When
3402 disabled, the radio will not transmit anything during flight
3407 <title>Telemetry baud rate</title>
3409 This sets the modulation bit rate for data transmission for
3410 both telemetry and packet link mode. Lower bit
3411 rates will increase range while reducing the amount of data
3412 that can be sent and increasing battery consumption. All
3413 telemetry is done using a rate 1/2 constraint 4 convolution
3414 code, so the actual data transmission rate is 1/2 of the
3415 modulation bit rate specified here.
3419 <title>APRS Interval</title>
3421 How often to transmit GPS information via APRS (in
3422 seconds). When set to zero, APRS transmission is
3423 disabled. This option is available on TeleMetrum v2 and
3424 TeleMega boards. TeleMetrum v1 boards cannot transmit APRS
3425 packets. Note that a single APRS packet takes nearly a full
3426 second to transmit, so enabling this option will prevent
3427 sending any other telemetry during that time.
3431 <title>APRS SSID</title>
3433 Which SSID to report in APRS packets. By default, this is
3434 set to the last digit of the serial number, but can be
3435 configured to any value from 0 to 9.
3439 <title>Callsign</title>
3441 This sets the call sign included in each telemetry packet. Set this
3442 as needed to conform to your local radio regulations.
3446 <title>Maximum Flight Log Size</title>
3448 This sets the space (in kilobytes) allocated for each flight
3449 log. The available space will be divided into chunks of this
3450 size. A smaller value will allow more flights to be stored,
3451 a larger value will record data from longer flights.
3455 <title>Ignitor Firing Mode</title>
3457 This configuration parameter allows the two standard ignitor
3458 channels (Apogee and Main) to be used in different
3463 <term>Dual Deploy</term>
3466 This is the usual mode of operation; the
3467 'apogee' channel is fired at apogee and the 'main'
3468 channel at the height above ground specified by the
3469 'Main Deploy Altitude' during descent.
3474 <term>Redundant Apogee</term>
3477 This fires both channels at
3478 apogee, the 'apogee' channel first followed after a two second
3479 delay by the 'main' channel.
3484 <term>Redundant Main</term>
3487 This fires both channels at the
3488 height above ground specified by the Main Deploy
3489 Altitude setting during descent. The 'apogee'
3490 channel is fired first, followed after a two second
3491 delay by the 'main' channel.
3498 <title>Pad Orientation</title>
3500 Because they include accelerometers, TeleMetrum,
3501 TeleMega and EasyMega are sensitive to the orientation of the board. By
3502 default, they expect the antenna end to point forward. This
3503 parameter allows that default to be changed, permitting the
3504 board to be mounted with the antenna pointing aft instead.
3508 <term>Antenna Up</term>
3511 In this mode, the antenna end of the
3512 flight computer must point forward, in line with the
3513 expected flight path.
3518 <term>Antenna Down</term>
3521 In this mode, the antenna end of the
3522 flight computer must point aft, in line with the
3523 expected flight path.
3530 <title>Beeper Frequency</title>
3532 The beeper on all Altus Metrum flight computers works best
3533 at 4000Hz, however if you have more than one flight computer
3534 in a single airframe, having all of them sound at the same
3535 frequency can be confusing. This parameter lets you adjust
3536 the base beeper frequency value.
3540 <title>Configure Pyro Channels</title>
3544 <imagedata fileref="configure-pyro.png" width="6in" scalefit="1"/>
3549 This opens a separate window to configure the additional
3550 pyro channels available on TeleMega and EasyMega. One column is
3551 presented for each channel. Each row represents a single
3552 parameter, if enabled the parameter must meet the specified
3553 test for the pyro channel to be fired. See the Pyro Channels
3554 section in the System Operation chapter above for a
3555 description of these parameters.
3558 Select conditions and set the related value; the pyro
3559 channel will be activated when <emphasis>all</emphasis> of the
3560 conditions are met. Each pyro channel has a separate set of
3561 configuration values, so you can use different values for
3562 the same condition with different channels.
3565 At the bottom of the window, the 'Pyro Firing Time'
3566 configuration sets the length of time (in seconds) which
3567 each of these pyro channels will fire for.
3570 Once you have selected the appropriate configuration for all
3571 of the necessary pyro channels, you can save the pyro
3572 configuration along with the rest of the flight computer
3573 configuration by pressing the 'Save' button in the main
3574 Configure Flight Computer window.
3579 <title>Configure AltosUI</title>
3583 <imagedata fileref="configure-altosui.png" width="2.4in" scalefit="1"/>
3588 This button presents a dialog so that you can configure the AltosUI global settings.
3591 <title>Voice Settings</title>
3593 AltosUI provides voice announcements during flight so that you
3594 can keep your eyes on the sky and still get information about
3595 the current flight status. However, sometimes you don't want
3602 <para>Turns all voice announcements on and off</para>
3606 <term>Test Voice</term>
3609 Plays a short message allowing you to verify
3610 that the audio system is working and the volume settings
3618 <title>Log Directory</title>
3620 AltosUI logs all telemetry data and saves all TeleMetrum flash
3621 data to this directory. This directory is also used as the
3622 staring point when selecting data files for display or export.
3625 Click on the directory name to bring up a directory choosing
3626 dialog, select a new directory and click 'Select Directory' to
3627 change where AltosUI reads and writes data files.
3631 <title>Callsign</title>
3633 This value is transmitted in each command packet sent from
3634 TeleDongle and received from an altimeter. It is not used in
3635 telemetry mode, as the callsign configured in the altimeter board
3636 is included in all telemetry packets. Configure this
3637 with the AltosUI operators call sign as needed to comply with
3638 your local radio regulations.
3641 Note that to successfully command a flight computer over the radio
3642 (to configure the altimeter, monitor idle, or fire pyro charges),
3643 the callsign configured here must exactly match the callsign
3644 configured in the flight computer. This matching is case
3649 <title>Imperial Units</title>
3651 This switches between metric units (meters) and imperial
3652 units (feet and miles). This affects the display of values
3653 use during flight monitoring, configuration, data graphing
3654 and all of the voice announcements. It does not change the
3655 units used when exporting to CSV files, those are always
3656 produced in metric units.
3660 <title>Font Size</title>
3662 Selects the set of fonts used in the flight monitor
3663 window. Choose between the small, medium and large sets.
3667 <title>Serial Debug</title>
3669 This causes all communication with a connected device to be
3670 dumped to the console from which AltosUI was started. If
3671 you've started it from an icon or menu entry, the output
3672 will simply be discarded. This mode can be useful to debug
3673 various serial communication issues.
3677 <title>Manage Frequencies</title>
3679 This brings up a dialog where you can configure the set of
3680 frequencies shown in the various frequency menus. You can
3681 add as many as you like, or even reconfigure the default
3682 set. Changing this list does not affect the frequency
3683 settings of any devices, it only changes the set of
3684 frequencies shown in the menus.
3689 <title>Configure Groundstation</title>
3693 <imagedata fileref="configure-groundstation.png" width="3.1in" scalefit="1"/>
3698 Select this button and then select a TeleDongle or TeleBT Device from the list provided.
3701 The first few lines of the dialog provide information about the
3702 connected device, including the product name,
3703 software version and hardware serial number. Below that are the
3704 individual configuration entries.
3707 Note that TeleDongle and TeleBT don't save any configuration
3708 data, the settings here are recorded on the local machine in
3709 the Java preferences database. Moving the device to
3710 another machine, or using a different user account on the same
3711 machine will cause settings made here to have no effect.
3714 At the bottom of the dialog, there are three buttons:
3721 This writes any changes to the
3722 local Java preferences file. If you don't
3723 press this button, any changes you make will be lost.
3731 This resets the dialog to the most recently saved values,
3732 erasing any changes you have made.
3740 This closes the dialog. Any unsaved changes will be
3747 The rest of the dialog contains the parameters to be configured.
3750 <title>Frequency</title>
3752 This configures the frequency to use for both telemetry and
3753 packet command mode. Set this before starting any operation
3754 involving packet command mode so that it will use the right
3755 frequency. Telemetry monitoring mode also provides a menu to
3756 change the frequency, and that menu also sets the same Java
3757 preference value used here.
3761 <title>RF Calibration</title>
3763 The radios in every Altus Metrum device are calibrated at the
3764 factory to ensure that they transmit and receive on the
3765 specified frequency. To change a TeleDongle or TeleBT's calibration,
3766 you must reprogram the unit completely, so this entry simply
3767 shows the current value and doesn't allow any changes.
3771 <title>Telemetry Rate</title>
3773 This lets you match the telemetry and packet link rate from
3774 the transmitter. If they don't match, the device won't
3780 <title>Flash Image</title>
3782 This reprograms Altus Metrum devices with new
3783 firmware. TeleMetrum v1.x, TeleDongle v0.2, TeleMini and
3784 TeleBT are all reprogrammed by using another similar unit as a
3785 programming dongle (pair programming). TeleMega, EasyMega,
3786 TeleMetrum v2, EasyMini and TeleDongle v3 are all programmed
3787 directly over their USB ports (self programming). Please read
3788 the directions for flashing devices in the Updating Device
3789 Firmware chapter below.
3793 <title>Fire Igniter</title>
3797 <imagedata fileref="fire-igniter.png" width="1.2in" scalefit="1"/>
3802 This activates the igniter circuits in the flight computer to help
3803 test recovery systems deployment. Because this command can operate
3804 over the Packet Command Link, you can prepare the rocket as
3805 for flight and then test the recovery system without needing
3806 to snake wires inside the air-frame.
3809 Selecting the 'Fire Igniter' button brings up the usual device
3810 selection dialog. Pick the desired device. This brings up another
3811 window which shows the current continuity test status for all
3812 of the pyro channels.
3815 Next, select the desired igniter to fire. This will enable the
3819 Select the 'Arm' button. This enables the 'Fire' button. The
3820 word 'Arm' is replaced by a countdown timer indicating that
3821 you have 10 seconds to press the 'Fire' button or the system
3822 will deactivate, at which point you start over again at
3823 selecting the desired igniter.
3827 <title>Scan Channels</title>
3831 <imagedata fileref="scan-channels.png" width="3.2in" scalefit="1"/>
3836 This listens for telemetry packets on all of the configured
3837 frequencies, displaying information about each device it
3838 receives a packet from. You can select which of the baud rates
3839 and telemetry formats should be tried; by default, it only listens
3840 at 38400 baud with the standard telemetry format used in v1.0 and later
3845 <title>Load Maps</title>
3849 <imagedata fileref="load-maps.png" width="5.2in" scalefit="1"/>
3854 Before heading out to a new launch site, you can use this to
3855 load satellite images in case you don't have internet
3856 connectivity at the site. This loads a fairly large area
3857 around the launch site, which should cover any flight you're likely to make.
3860 There's a drop-down menu of launch sites we know about; if
3861 your favorites aren't there, please let us know the lat/lon
3862 and name of the site. The contents of this list are actually
3863 downloaded from our server at run-time, so as new sites are sent
3864 in, they'll get automatically added to this list.
3865 If the launch site isn't in the list, you can manually enter the lat/lon values
3868 There are four different kinds of maps you can view; you can
3869 select which to download by selecting as many as you like from
3870 the available types:
3876 A combination of satellite imagery and road data. This
3877 is the default view.
3882 <term>Satellite</term>
3885 Just the satellite imagery without any annotation.
3890 <term>Roadmap</term>
3893 Roads, political boundaries and a few geographic features.
3898 <term>Terrain</term>
3901 Contour intervals and shading that show hills and
3909 You can specify the range of zoom levels to download; smaller
3910 numbers show more area with less resolution. The default
3911 level, 0, shows about 3m/pixel. One zoom level change
3912 doubles or halves that number.
3915 The Tile Radius value sets how large an area around the center
3916 point to download. Each tile is 512x512 pixels, and the
3917 'radius' value specifies how many tiles away from the center
3918 will be downloaded. Specify a radius of 0 and you get only the
3919 center tile. A radius of 1 loads a 3x3 grid, centered on the
3923 Clicking the 'Load Map' button will fetch images from Google
3924 Maps; note that Google limits how many images you can fetch at
3925 once, so if you load more than one launch site, you may get
3926 some gray areas in the map which indicate that Google is tired
3927 of sending data to you. Try again later.
3931 <title>Monitor Idle</title>
3933 This brings up a dialog similar to the Monitor Flight UI,
3934 except it works with the altimeter in “idle” mode by sending
3935 query commands to discover the current state rather than
3936 listening for telemetry packets. Because this uses command
3937 mode, it needs to have the TeleDongle and flight computer
3938 callsigns match exactly. If you can receive telemetry, but
3939 cannot manage to run Monitor Idle, then it's very likely that
3940 your callsigns are different in some way.
3945 <title>AltosDroid</title>
3947 AltosDroid provides the same flight monitoring capabilities as
3948 AltosUI, but runs on Android devices and is designed to connect
3949 to a TeleBT receiver over Bluetooth™. AltosDroid monitors
3950 telemetry data, logging it to internal storage in the Android
3951 device, and presents that data in a UI the same way the 'Monitor
3952 Flight' window does in AltosUI.
3955 This manual will explain how to configure AltosDroid, connect
3956 to TeleBT, operate the flight monitoring interface and describe
3957 what the displayed data means.
3960 <title>Installing AltosDroid</title>
3962 AltosDroid is available from the Google Play store. To install
3963 it on your Android device, open the Google Play Store
3964 application and search for “altosdroid”. Make sure you don't
3965 have a space between “altos” and “droid” or you probably won't
3966 find what you want. That should bring you to the right page
3967 from which you can download and install the application.
3971 <title>Connecting to TeleBT</title>
3973 Press the Android 'Menu' button or soft-key to see the
3974 configuration options available. Select the 'Connect a device'
3975 option and then the 'Scan for devices' entry at the bottom to
3976 look for your TeleBT device. Select your device, and when it
3977 asks for the code, enter '1234'.
3980 Subsequent connections will not require you to enter that
3981 code, and your 'paired' device will appear in the list without
3986 <title>Configuring AltosDroid</title>
3988 The only configuration option available for AltosDroid is
3989 which frequency to listen on. Press the Android 'Menu' button
3990 or soft-key and pick the 'Select radio frequency' entry. That
3991 brings up a menu of pre-set radio frequencies; pick the one
3992 which matches your altimeter.
3996 <title>AltosDroid Flight Monitoring</title>
3998 AltosDroid is designed to mimic the AltosUI flight monitoring
3999 display, providing separate tabs for each stage of your rocket
4000 flight along with a tab containing a map of the local area
4001 with icons marking the current location of the altimeter and
4007 The 'Launch Pad' tab shows information used to decide when the
4008 rocket is ready for flight. The first elements include red/green
4009 indicators, if any of these is red, you'll want to evaluate
4010 whether the rocket is ready to launch:
4013 <term>Battery Voltage</term>
4016 This indicates whether the Li-Po battery
4017 powering the TeleMetrum has sufficient charge to last for
4018 the duration of the flight. A value of more than
4019 3.8V is required for a 'GO' status.
4024 <term>Apogee Igniter Voltage</term>
4027 This indicates whether the apogee
4028 igniter has continuity. If the igniter has a low
4029 resistance, then the voltage measured here will be close
4030 to the Li-Po battery voltage. A value greater than 3.2V is
4031 required for a 'GO' status.
4036 <term>Main Igniter Voltage</term>
4039 This indicates whether the main
4040 igniter has continuity. If the igniter has a low
4041 resistance, then the voltage measured here will be close
4042 to the Li-Po battery voltage. A value greater than 3.2V is
4043 required for a 'GO' status.
4048 <term>On-board Data Logging</term>
4051 This indicates whether there is
4052 space remaining on-board to store flight data for the
4053 upcoming flight. If you've downloaded data, but failed
4054 to erase flights, there may not be any space
4055 left. TeleMetrum can store multiple flights, depending
4056 on the configured maximum flight log size. TeleMini
4057 stores only a single flight, so it will need to be
4058 downloaded and erased after each flight to capture
4059 data. This only affects on-board flight logging; the
4060 altimeter will still transmit telemetry and fire
4061 ejection charges at the proper times.
4066 <term>GPS Locked</term>
4069 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
4070 currently able to compute position information. GPS requires
4071 at least 4 satellites to compute an accurate position.
4076 <term>GPS Ready</term>
4079 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
4080 10 consecutive positions without losing lock. This ensures
4081 that the GPS receiver has reliable reception from the
4089 The Launchpad tab also shows the computed launch pad position
4090 and altitude, averaging many reported positions to improve the
4091 accuracy of the fix.
4096 <title>Downloading Flight Logs</title>
4098 AltosDroid always saves every bit of telemetry data it
4099 receives. To download that to a computer for use with AltosUI,
4100 simply remove the SD card from your Android device, or connect
4101 your device to your computer's USB port and browse the files
4102 on that device. You will find '.telem' files in the TeleMetrum
4103 directory that will work with AltosUI directly.
4108 <title>Using Altus Metrum Products</title>
4110 <title>Being Legal</title>
4112 First off, in the US, you need an <ulink url="http://www.altusmetrum.org/Radio/">amateur radio license</ulink> or
4113 other authorization to legally operate the radio transmitters that are part
4118 <title>In the Rocket</title>
4120 In the rocket itself, you just need a flight computer and
4121 a single-cell, 3.7 volt nominal Li-Po rechargeable battery. An
4122 850mAh battery weighs less than a 9V alkaline battery, and will
4123 run a TeleMetrum, TeleMega or EasyMega for hours.
4124 A 110mAh battery weighs less than a triple A battery and is a good
4125 choice for use with TeleMini or EasyMini.
4128 By default, we ship TeleMini, TeleMetrum and TeleMega flight computers with a simple wire antenna.
4129 If your electronics bay or the air-frame it resides within is made
4130 of carbon fiber, which is opaque to RF signals, you may prefer to
4131 install an SMA connector so that you can run a coaxial cable to an
4132 antenna mounted elsewhere in the rocket. However, note that the
4133 GPS antenna is fixed on all current products, so you really want
4134 to install the flight computer in a bay made of RF-transparent
4135 materials if at all possible.
4139 <title>On the Ground</title>
4141 To receive the data stream from the rocket, you need an antenna and short
4142 feed-line connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. If possible, use an SMA to BNC
4143 adapter instead of feedline between the antenna feedpoint and
4144 TeleDongle, as this will give you the best performance. The
4145 TeleDongle in turn plugs directly into the USB port on a notebook
4146 computer. Because TeleDongle looks like a simple serial port, your computer
4147 does not require special device drivers... just plug it in.
4150 The GUI tool, AltosUI, is written in Java and runs across
4151 Linux, Mac OS and Windows. There's also a suite of C tools
4152 for Linux which can perform most of the same tasks.
4155 Alternatively, a TeleBT attached with an SMA to BNC adapter at the
4156 feed point of a hand-held yagi used in conjunction with an Android
4157 device running AltosDroid makes an outstanding ground station.
4160 After the flight, you can use the radio link to extract the more detailed data
4161 logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
4162 TeleMetrum board directly. Pulling out the data without having to open up
4163 the rocket is pretty cool! A USB cable is also how you charge the Li-Po
4164 battery, so you'll want one of those anyway... the same cable used by lots
4165 of digital cameras and other modern electronic stuff will work fine.
4168 If your rocket lands out of sight, you may enjoy having a hand-held
4169 GPS receiver, so that you can put in a way-point for the last
4170 reported rocket position before touch-down. This makes looking for
4171 your rocket a lot like Geo-Caching... just go to the way-point and
4172 look around starting from there. AltosDroid on an Android device
4173 with GPS receiver works great for this, too!
4176 You may also enjoy having a ham radio “HT” that covers the 70cm band... you
4177 can use that with your antenna to direction-find the rocket on the ground
4178 the same way you can use a Walston or Beeline tracker. This can be handy
4179 if the rocket is hiding in sage brush or a tree, or if the last GPS position
4180 doesn't get you close enough because the rocket dropped into a canyon, or
4181 the wind is blowing it across a dry lake bed, or something like that... Keith
4182 currently uses a Yaesu FT1D, Bdale has a Yaesu VX-7R, which
4183 is a nicer radio in most ways but doesn't support APRS.
4186 So, to recap, on the ground the hardware you'll need includes:
4187 <orderedlist inheritnum='inherit' numeration='arabic'>
4190 an antenna and feed-line or adapter
4205 optionally, a hand-held GPS receiver
4210 optionally, an HT or receiver covering 435 MHz
4216 The best hand-held commercial directional antennas we've found for radio
4217 direction finding rockets are from
4218 <ulink url="http://www.arrowantennas.com/" >
4221 The 440-3 and 440-5 are both good choices for finding a
4222 TeleMetrum- or TeleMini- equipped rocket when used with a suitable
4223 70cm HT. TeleDongle and an SMA to BNC adapter fit perfectly
4224 between the driven element and reflector of Arrow antennas.
4228 <title>Data Analysis</title>
4230 Our software makes it easy to log the data from each flight, both the
4231 telemetry received during the flight itself, and the more
4232 complete data log recorded in the flash memory on the altimeter
4233 board. Once this data is on your computer, our post-flight tools make it
4234 easy to quickly get to the numbers everyone wants, like apogee altitude,
4235 max acceleration, and max velocity. You can also generate and view a
4236 standard set of plots showing the altitude, acceleration, and
4237 velocity of the rocket during flight. And you can even export a TeleMetrum data file
4238 usable with Google Maps and Google Earth for visualizing the flight path
4239 in two or three dimensions!
4242 Our ultimate goal is to emit a set of files for each flight that can be
4243 published as a web page per flight, or just viewed on your local disk with
4248 <title>Future Plans</title>
4250 We have designed and prototyped several “companion boards” that
4251 can attach to the companion connector on TeleMetrum,
4252 TeleMega and EasyMega
4253 flight computers to collect more data, provide more pyro channels,
4254 and so forth. We do not yet know if or when any of these boards
4255 will be produced in enough quantity to sell. If you have specific
4256 interests for data collection or control of events in your rockets
4257 beyond the capabilities of our existing productions, please let
4261 Because all of our work is open, both the hardware designs and the
4262 software, if you have some great idea for an addition to the current
4263 Altus Metrum family, feel free to dive in and help! Or let us know
4264 what you'd like to see that we aren't already working on, and maybe
4265 we'll get excited about it too...
4269 <ulink url="http://altusmetrum.org/">web site</ulink> for more news
4270 and information as our family of products evolves!
4275 <title>Altimeter Installation Recommendations</title>
4277 Building high-power rockets that fly safely is hard enough. Mix
4278 in some sophisticated electronics and a bunch of radio energy
4279 and some creativity and/or compromise may be required. This chapter
4280 contains some suggestions about how to install Altus Metrum
4281 products into a rocket air-frame, including how to safely and
4282 reliably mix a variety of electronics into the same air-frame.
4285 <title>Mounting the Altimeter</title>
4287 The first consideration is to ensure that the altimeter is
4288 securely fastened to the air-frame. For most of our products, we
4289 prefer nylon standoffs and nylon screws; they're good to at least 50G
4290 and cannot cause any electrical issues on the board. Metal screws
4291 and standoffs are fine, too, just be careful to avoid electrical
4292 shorts! For TeleMini v1.0, we usually cut small pieces of 1/16 inch
4294 under the screw holes, and then take 2x56 nylon screws and
4295 screw them through the TeleMini mounting holes, through the
4296 balsa and into the underlying material.
4298 <orderedlist inheritnum='inherit' numeration='arabic'>
4301 Make sure accelerometer-equipped products like TeleMetrum,
4302 TeleMega and EasyMega are aligned precisely along the axis of
4303 acceleration so that the accelerometer can accurately
4304 capture data during the flight.
4309 Watch for any metal touching components on the
4310 board. Shorting out connections on the bottom of the board
4311 can cause the altimeter to fail during flight.
4317 <title>Dealing with the Antenna</title>
4319 The antenna supplied is just a piece of solid, insulated,
4320 wire. If it gets damaged or broken, it can be easily
4321 replaced. It should be kept straight and not cut; bending or
4322 cutting it will change the resonant frequency and/or
4323 impedance, making it a less efficient radiator and thus
4324 reducing the range of the telemetry signal.
4327 Keeping metal away from the antenna will provide better range
4328 and a more even radiation pattern. In most rockets, it's not
4329 entirely possible to isolate the antenna from metal
4330 components; there are often bolts, all-thread and wires from other
4331 electronics to contend with. Just be aware that the more stuff
4332 like this around the antenna, the lower the range.
4335 Make sure the antenna is not inside a tube made or covered
4336 with conducting material. Carbon fiber is the most common
4337 culprit here -- CF is a good conductor and will effectively
4338 shield the antenna, dramatically reducing signal strength and
4339 range. Metallic flake paint is another effective shielding
4340 material which should be avoided around any antennas.
4343 If the ebay is large enough, it can be convenient to simply
4344 mount the altimeter at one end and stretch the antenna out
4345 inside. Taping the antenna to the sled can keep it straight
4346 under acceleration. If there are metal rods, keep the
4347 antenna as far away as possible.
4350 For a shorter ebay, it's quite practical to have the antenna
4351 run through a bulkhead and into an adjacent bay. Drill a small
4352 hole in the bulkhead, pass the antenna wire through it and
4353 then seal it up with glue or clay. We've also used acrylic
4354 tubing to create a cavity for the antenna wire. This works a
4355 bit better in that the antenna is known to stay straight and
4356 not get folded by recovery components in the bay. Angle the
4357 tubing towards the side wall of the rocket and it ends up
4358 consuming very little space.
4361 If you need to place the UHF antenna at a distance from the
4362 altimeter, you can replace the antenna with an edge-mounted
4363 SMA connector, and then run 50Ω coax from the board to the
4364 antenna. Building a remote antenna is beyond the scope of this
4369 <title>Preserving GPS Reception</title>
4371 The GPS antenna and receiver used in TeleMetrum and TeleMega is
4372 highly sensitive and normally have no trouble tracking enough
4373 satellites to provide accurate position information for
4374 recovering the rocket. However, there are many ways the GPS signal
4375 can end up attenuated, negatively affecting GPS performance.
4376 <orderedlist inheritnum='inherit' numeration='arabic'>
4379 Conductive tubing or coatings. Carbon fiber and metal
4380 tubing, or metallic paint will all dramatically attenuate the
4381 GPS signal. We've never heard of anyone successfully
4382 receiving GPS from inside these materials.
4387 Metal components near the GPS patch antenna. These will
4388 de-tune the patch antenna, changing the resonant frequency
4389 away from the L1 carrier and reduce the effectiveness of the
4390 antenna. You can place as much stuff as you like beneath the
4391 antenna as that's covered with a ground plane. But, keep
4392 wires and metal out from above the patch antenna.
4399 <title>Radio Frequency Interference</title>
4401 Any altimeter will generate RFI; the digital circuits use
4402 high-frequency clocks that spray radio interference across a
4403 wide band. Altus Metrum altimeters generate intentional radio
4404 signals as well, increasing the amount of RF energy around the board.
4407 Rocketry altimeters also use precise sensors measuring air
4408 pressure and acceleration. Tiny changes in voltage can cause
4409 these sensor readings to vary by a huge amount. When the
4410 sensors start mis-reporting data, the altimeter can either
4411 fire the igniters at the wrong time, or not fire them at all.
4414 Voltages are induced when radio frequency energy is
4415 transmitted from one circuit to another. Here are things that
4416 influence the induced voltage and current:
4421 Keep wires from different circuits apart. Moving circuits
4422 further apart will reduce RFI.
4427 Avoid parallel wires from different circuits. The longer two
4428 wires run parallel to one another, the larger the amount of
4429 transferred energy. Cross wires at right angles to reduce
4435 Twist wires from the same circuits. Two wires the same
4436 distance from the transmitter will get the same amount of
4437 induced energy which will then cancel out. Any time you have
4438 a wire pair running together, twist the pair together to
4439 even out distances and reduce RFI. For altimeters, this
4440 includes battery leads, switch hookups and igniter
4446 Avoid resonant lengths. Know what frequencies are present
4447 in the environment and avoid having wire lengths near a
4448 natural resonant length. Altus Metrum products transmit on the
4449 70cm amateur band, so you should avoid lengths that are a
4450 simple ratio of that length; essentially any multiple of ¼
4451 of the wavelength (17.5cm).
4457 <title>The Barometric Sensor</title>
4459 Altusmetrum altimeters measure altitude with a barometric
4460 sensor, essentially measuring the amount of air above the
4461 rocket to figure out how high it is. A large number of
4462 measurements are taken as the altimeter initializes itself to
4463 figure out the pad altitude. Subsequent measurements are then
4464 used to compute the height above the pad.
4467 To accurately measure atmospheric pressure, the ebay
4468 containing the altimeter must be vented outside the
4469 air-frame. The vent must be placed in a region of linear
4470 airflow, have smooth edges, and away from areas of increasing or
4471 decreasing pressure.
4474 All barometric sensors are quite sensitive to chemical damage from
4475 the products of APCP or BP combustion, so make sure the ebay is
4476 carefully sealed from any compartment which contains ejection
4481 <title>Ground Testing</title>
4483 The most important aspect of any installation is careful
4484 ground testing. Bringing an air-frame up to the LCO table which
4485 hasn't been ground tested can lead to delays or ejection
4486 charges firing on the pad, or, even worse, a recovery system
4490 Do a 'full systems' test that includes wiring up all igniters
4491 without any BP and turning on all of the electronics in flight
4492 mode. This will catch any mistakes in wiring and any residual
4493 RFI issues that might accidentally fire igniters at the wrong
4494 time. Let the air-frame sit for several minutes, checking for
4495 adequate telemetry signal strength and GPS lock. If any igniters
4496 fire unexpectedly, find and resolve the issue before loading any
4500 Ground test the ejection charges. Prepare the rocket for
4501 flight, loading ejection charges and igniters. Completely
4502 assemble the air-frame and then use the 'Fire Igniters'
4503 interface through a TeleDongle to command each charge to
4504 fire. Make sure the charge is sufficient to robustly separate
4505 the air-frame and deploy the recovery system.
4510 <title>Updating Device Firmware</title>
4512 TeleMega, TeleMetrum v2, EasyMega, EasyMini and TeleDongle v3
4513 are all programmed directly over their USB connectors (self
4514 programming). TeleMetrum v1, TeleMini and TeleDongle v0.2 are
4515 all programmed by using another device as a programmer (pair
4516 programming). It's important to recognize which kind of devices
4517 you have before trying to reprogram them.
4520 You may wish to begin by ensuring you have current firmware images.
4521 These are distributed as part of the AltOS software bundle that
4522 also includes the AltosUI ground station program. Newer ground
4523 station versions typically work fine with older firmware versions,
4524 so you don't need to update your devices just to try out new
4525 software features. You can always download the most recent
4526 version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
4529 If you need to update the firmware on a TeleDongle v0.2, we recommend
4530 updating the altimeter first, before updating TeleDongle. However,
4531 note that TeleDongle rarely need to be updated. Any firmware version
4532 1.0.1 or later will work, version 1.2.1 may have improved receiver
4533 performance slightly.
4536 Self-programmable devices (TeleMega, TeleMetrum v2, EasyMega and EasyMini)
4537 are reprogrammed by connecting them to your computer over USB
4541 Updating TeleMega, TeleMetrum v2, EasyMega, EasyMini or
4542 TeleDongle v3 Firmware
4544 <orderedlist inheritnum='inherit' numeration='arabic'>
4547 Attach a battery if necessary and power switch to the target
4548 device. Power up the device.
4553 Using a Micro USB cable, connect the target device to your
4554 computer's USB socket.
4559 Run AltosUI, and select 'Flash Image' from the File menu.
4564 Select the target device in the Device Selection dialog.
4569 Select the image you want to flash to the device, which
4570 should have a name in the form
4571 <product>-v<product-version>-<software-version>.ihx, such
4572 as TeleMega-v1.0-1.3.0.ihx.
4577 Make sure the configuration parameters are reasonable
4578 looking. If the serial number and/or RF configuration
4579 values aren't right, you'll need to change them.
4584 Hit the 'OK' button and the software should proceed to flash
4585 the device with new firmware, showing a progress bar.
4590 Verify that the device is working by using the 'Configure
4591 Altimeter' or 'Configure Groundstation' item to check over
4597 <title>Recovering From Self-Flashing Failure</title>
4599 If the firmware loading fails, it can leave the device
4600 unable to boot. Not to worry, you can force the device to
4601 start the boot loader instead, which will let you try to
4602 flash the device again.
4605 On each device, connecting two pins from one of the exposed
4606 connectors will force the boot loader to start, even if the
4607 regular operating system has been corrupted in some way.
4611 <term>TeleMega</term>
4614 Connect pin 6 and pin 1 of the companion connector. Pin 1
4615 can be identified by the square pad around it, and then
4616 the pins could sequentially across the board. Be very
4617 careful to <emphasis>not</emphasis> short pin 8 to
4618 anything as that is connected directly to the battery. Pin
4619 7 carries 3.3V and the board will crash if that is
4620 connected to pin 1, but shouldn't damage the board.
4625 <term>EasyMega</term>
4628 Connect pin 6 and pin 1 of the companion connector. Pin 1
4629 can be identified by the square pad around it, and then
4630 the pins could sequentially across the board. Be very
4631 careful to <emphasis>not</emphasis> short pin 8 to
4632 anything as that is connected directly to the battery. Pin
4633 7 carries 3.3V and the board will crash if that is
4634 connected to pin 1, but shouldn't damage the board.
4639 <term>TeleMetrum v2</term>
4642 Connect pin 6 and pin 1 of the companion connector. Pin 1
4643 can be identified by the square pad around it, and then
4644 the pins could sequentially across the board. Be very
4645 careful to <emphasis>not</emphasis> short pin 8 to
4646 anything as that is connected directly to the battery. Pin
4647 7 carries 3.3V and the board will crash if that is
4648 connected to pin 1, but shouldn't damage the board.
4653 <term>EasyMini</term>
4656 Connect pin 6 and pin 1 of the debug connector, which is
4657 the six holes next to the beeper. Pin 1 can be identified
4658 by the square pad around it, and then the pins could
4659 sequentially across the board, making Pin 6 the one on the
4660 other end of the row.
4665 <term>TeleDongle v3</term>
4668 Connect pin 32 on the CPU to ground. Pin 32 is closest
4669 to the USB wires on the row of pins towards the center
4670 of the board. Ground is available on the capacitor
4671 next to it, on the end towards the USB wires.
4677 Once you've located the right pins:
4679 <orderedlist inheritnum='inherit' numeration='arabic'>
4682 Turn the altimeter power off.
4692 Connect the indicated terminals together with a short
4693 piece of wire. Take care not to accidentally connect
4704 Turn the board power on.
4709 The board should now be visible over USB as 'AltosFlash'
4710 and be ready to receive firmware.
4715 Once the board has been powered up, you can remove the
4723 <title>Pair Programming</title>
4725 The big concept to understand is that you have to use a
4726 TeleMetrum v1.0, TeleBT v1.0 or TeleDongle v0.2 as a
4727 programmer to update a pair programmed device. Due to limited
4728 memory resources in the cc1111, we don't support programming
4729 directly over USB for these devices.
4733 <title>Updating TeleMetrum v1.x Firmware</title>
4734 <orderedlist inheritnum='inherit' numeration='arabic'>
4737 Find the 'programming cable' that you got as part of the starter
4738 kit, that has a red 8-pin MicroMaTch connector on one end and a
4739 red 4-pin MicroMaTch connector on the other end.
4744 Take the 2 screws out of the TeleDongle v0.2 or TeleBT v1.0
4745 case to get access to the circuit board.
4750 Plug the 8-pin end of the programming cable to the
4751 matching connector on the TeleDongle v0.2 or TeleBT v1.0, and the 4-pin end to the
4752 matching connector on the TeleMetrum.
4753 Note that each MicroMaTch connector has an alignment pin that
4754 goes through a hole in the PC board when you have the cable
4760 Attach a battery to the TeleMetrum board.
4765 Plug the TeleDongle v0.2 or TeleBT v1.0 into your computer's USB port, and power
4771 Run AltosUI, and select 'Flash Image' from the File menu.
4776 Pick the TeleDongle v0.2 or TeleBT v1.0 device from the list, identifying it as the
4782 Select the image you want put on the TeleMetrum, which should have a
4783 name in the form telemetrum-v1.2-1.0.0.ihx. It should be visible
4784 in the default directory, if not you may have to poke around
4785 your system to find it.
4790 Make sure the configuration parameters are reasonable
4791 looking. If the serial number and/or RF configuration
4792 values aren't right, you'll need to change them.
4797 Hit the 'OK' button and the software should proceed to flash
4798 the TeleMetrum with new firmware, showing a progress bar.
4803 Confirm that the TeleMetrum board seems to have updated OK, which you
4804 can do by plugging in to it over USB and using a terminal program
4805 to connect to the board and issue the 'v' command to check
4811 If something goes wrong, give it another try.
4817 <title>Updating TeleMini Firmware</title>
4818 <orderedlist inheritnum='inherit' numeration='arabic'>
4821 You'll need a special 'programming cable' to reprogram the
4822 TeleMini. You can make your own using an 8-pin MicroMaTch
4823 connector on one end and a set of four pins on the other.
4828 Take the 2 screws out of the TeleDongle v0.2 or TeleBT v1.0 case to get access
4829 to the circuit board.
4834 Plug the 8-pin end of the programming cable to the matching
4835 connector on the TeleDongle v0.2 or TeleBT v1.0, and the 4-pins into the holes
4836 in the TeleMini circuit board. Note that the MicroMaTch
4837 connector has an alignment pin that goes through a hole in
4838 the PC board when you have the cable oriented correctly, and
4839 that pin 1 on the TeleMini board is marked with a square pad
4840 while the other pins have round pads.
4845 Attach a battery to the TeleMini board.
4850 Plug the TeleDongle v0.2 or TeleBT v1.0 into your computer's USB port, and power
4856 Run AltosUI, and select 'Flash Image' from the File menu.
4861 Pick the TeleDongle v0.2 or TeleBT v1.0 device from the list, identifying it as the
4867 Select the image you want put on the TeleMini, which should have a
4868 name in the form telemini-v1.0-1.0.0.ihx. It should be visible
4869 in the default directory, if not you may have to poke around
4870 your system to find it.
4875 Make sure the configuration parameters are reasonable
4876 looking. If the serial number and/or RF configuration
4877 values aren't right, you'll need to change them.
4882 Hit the 'OK' button and the software should proceed to flash
4883 the TeleMini with new firmware, showing a progress bar.
4888 Confirm that the TeleMini board seems to have updated OK, which you
4889 can do by configuring it over the radio link through the TeleDongle, or
4890 letting it come up in “flight” mode and listening for telemetry.
4895 If something goes wrong, give it another try.
4901 <title>Updating TeleDongle v0.2 Firmware</title>
4903 Updating TeleDongle v0.2 firmware is just like updating
4904 TeleMetrum v1.x or TeleMini
4905 firmware, but you use either a TeleMetrum v1.x, TeleDongle
4906 v0.2 or TeleBT v1.0 as the programmer.
4908 <orderedlist inheritnum='inherit' numeration='arabic'>
4911 Find the 'programming cable' that you got as part of the starter
4912 kit, that has a red 8-pin MicroMaTch connector on one end and a
4913 red 4-pin MicroMaTch connector on the other end.
4918 Find the USB cable that you got as part of the starter kit, and
4919 plug the “mini” end in to the mating connector on TeleMetrum
4920 v1.x, TeleDongle v0.2 or TeleBT v1.0.
4925 Take the 2 screws out of the TeleDongle v0.2 or TeleBT v1.0 case to get access
4926 to the circuit board.
4931 Plug the 8-pin end of the programming cable to the
4932 matching connector on the programmer, and the 4-pin end to the
4933 matching connector on the TeleDongle v0.2.
4934 Note that each MicroMaTch connector has an alignment pin that
4935 goes through a hole in the PC board when you have the cable
4941 Attach a battery to the TeleMetrum v1.x board if you're using one.
4946 Plug both the programmer and the TeleDongle into your computer's USB
4947 ports, and power up the programmer.
4952 Run AltosUI, and select 'Flash Image' from the File menu.
4957 Pick the programmer device from the list, identifying it as the
4963 Select the image you want put on the TeleDongle v0.2, which should have a
4964 name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
4965 in the default directory, if not you may have to poke around
4966 your system to find it.
4971 Make sure the configuration parameters are reasonable
4972 looking. If the serial number and/or RF configuration
4973 values aren't right, you'll need to change them. The
4975 serial number is on the “bottom” of the circuit board, and can
4976 usually be read through the translucent blue plastic case without
4977 needing to remove the board from the case.
4982 Hit the 'OK' button and the software should proceed to flash
4983 the TeleDongle v0.2 with new firmware, showing a progress bar.
4988 Confirm that the TeleDongle v0.2 board seems to have updated OK, which you
4989 can do by plugging in to it over USB and using a terminal program
4990 to connect to the board and issue the 'v' command to check
4991 the version, etc. Once you're happy, remove the programming cable
4992 and put the cover back on the TeleDongle v0.2.
4997 If something goes wrong, give it another try.
5002 Be careful removing the programming cable from the locking 8-pin
5003 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
5004 screwdriver or knife blade to gently pry the locking ears out
5005 slightly to extract the connector. We used a locking connector on
5006 TeleMetrum to help ensure that the cabling to companion boards
5007 used in a rocket don't ever come loose accidentally in flight.
5012 <title>Hardware Specifications</title>
5015 TeleMega Specifications
5020 Recording altimeter for model rocketry.
5025 Supports dual deployment and four auxiliary pyro channels
5026 (a total of 6 events).
5031 70cm 40mW ham-band transceiver for telemetry down-link.
5036 Barometric pressure sensor good to 100k feet MSL.
5041 1-axis high-g accelerometer for motor characterization, capable of
5047 9-axis IMU including integrated 3-axis accelerometer,
5048 3-axis gyroscope and 3-axis magnetometer.
5053 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
5058 On-board 8 Megabyte non-volatile memory for flight data storage.
5063 USB interface for battery charging, configuration, and data recovery.
5068 Fully integrated support for Li-Po rechargeable batteries.
5073 Can use either main system Li-Po or optional separate pyro battery
5079 3.25 x 1.25 inch board designed to fit inside 38mm air-frame coupler tube.
5086 EasyMega Specifications
5091 Recording altimeter for model rocketry.
5096 Supports dual deployment and four auxiliary pyro channels
5097 (a total of 6 events).
5102 Barometric pressure sensor good to 100k feet MSL.
5107 1-axis high-g accelerometer for motor characterization, capable of
5113 9-axis IMU including integrated 3-axis accelerometer,
5114 3-axis gyroscope and 3-axis magnetometer.
5119 On-board 8 Megabyte non-volatile memory for flight data storage.
5124 USB interface for battery charging, configuration, and data recovery.
5129 Fully integrated support for Li-Po rechargeable batteries.
5134 Can use either main system Li-Po or optional separate pyro battery
5140 1.25 x 1.25 inch board designed to fit inside 38mm air-frame coupler tube.
5147 TeleMetrum v2 Specifications
5152 Recording altimeter for model rocketry.
5157 Supports dual deployment (can fire 2 ejection charges).
5162 70cm, 40mW ham-band transceiver for telemetry down-link.
5167 Barometric pressure sensor good to 100k feet MSL.
5172 1-axis high-g accelerometer for motor characterization, capable of
5178 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
5183 On-board 8 Megabyte non-volatile memory for flight data storage.
5188 USB interface for battery charging, configuration, and data recovery.
5193 Fully integrated support for Li-Po rechargeable batteries.
5198 Uses Li-Po to fire e-matches, can be modified to support
5199 optional separate pyro battery if needed.
5204 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
5210 <title>TeleMetrum v1 Specifications</title>
5214 Recording altimeter for model rocketry.
5219 Supports dual deployment (can fire 2 ejection charges).
5224 70cm, 10mW ham-band transceiver for telemetry down-link.
5229 Barometric pressure sensor good to 45k feet MSL.
5234 1-axis high-g accelerometer for motor characterization, capable of
5235 +/- 50g using default part.
5240 On-board, integrated GPS receiver with 5Hz update rate capability.
5245 On-board 1 megabyte non-volatile memory for flight data storage.
5250 USB interface for battery charging, configuration, and data recovery.
5255 Fully integrated support for Li-Po rechargeable batteries.
5260 Uses Li-Po to fire e-matches, can be modified to support
5261 optional separate pyro battery if needed.
5266 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
5273 TeleMini v2.0 Specifications
5278 Recording altimeter for model rocketry.
5283 Supports dual deployment (can fire 2 ejection charges).
5288 70cm, 10mW ham-band transceiver for telemetry down-link.
5293 Barometric pressure sensor good to 100k feet MSL.
5298 On-board 1 megabyte non-volatile memory for flight data storage.
5303 USB interface for configuration, and data recovery.
5308 Support for Li-Po rechargeable batteries (using an
5309 external charger), or any 3.7-15V external battery.
5314 Uses Li-Po to fire e-matches, can be modified to support
5315 optional separate pyro battery if needed.
5320 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
5327 TeleMini v1.0 Specifications
5332 Recording altimeter for model rocketry.
5337 Supports dual deployment (can fire 2 ejection charges).
5342 70cm, 10mW ham-band transceiver for telemetry down-link.
5347 Barometric pressure sensor good to 45k feet MSL.
5352 On-board 5 kilobyte non-volatile memory for flight data storage.
5357 RF interface for configuration, and data recovery.
5362 Support for Li-Po rechargeable batteries, using an external charger.
5367 Uses Li-Po to fire e-matches, can be modified to support
5368 optional separate pyro battery if needed.
5373 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube.
5380 EasyMini Specifications
5385 Recording altimeter for model rocketry.
5390 Supports dual deployment (can fire 2 ejection charges).
5395 Barometric pressure sensor good to 100k feet MSL.
5400 On-board 1 megabyte non-volatile memory for flight data storage.
5405 USB interface for configuration, and data recovery.
5410 Support for Li-Po rechargeable batteries (using an
5411 external charger), or any 3.7-15V external battery.
5416 Uses Li-Po to fire e-matches, can be modified to support
5417 optional separate pyro battery if needed.
5422 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
5431 <emphasis>TeleMetrum seems to shut off when disconnected from the
5432 computer.</emphasis> <?linebreak?>
5433 Make sure the battery is adequately charged. Remember the
5434 unit will pull more power than the USB port can deliver before the
5435 GPS enters “locked” mode. The battery charges best when TeleMetrum
5439 <emphasis>It's impossible to stop the TeleDongle when it's in “p” mode, I have
5440 to unplug the USB cable? </emphasis><?linebreak?>
5441 Make sure you have tried to “escape out” of
5442 this mode. If this doesn't work the reboot procedure for the
5443 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
5444 outgoing buffer IF your “escape out” ('~~') does not work.
5445 At this point using either 'ao-view' (or possibly
5446 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
5450 <emphasis>The amber LED (on the TeleMetrum) lights up when both
5451 battery and USB are connected. Does this mean it's charging?
5452 </emphasis><?linebreak?>
5453 Yes, the yellow LED indicates the charging at the 'regular' rate.
5454 If the led is out but the unit is still plugged into a USB port,
5455 then the battery is being charged at a 'trickle' rate.
5458 <emphasis>There are no “dit-dah-dah-dit” sound or lights like the manual
5459 mentions?</emphasis><?linebreak?>
5460 That's the “pad” mode. Weak batteries might be the problem.
5461 It is also possible that the flight computer is horizontal and the
5463 is instead a “dit-dit” meaning 'idle'. For TeleMini, it's possible that
5464 it received a command packet which would have left it in “pad” mode.
5467 <emphasis>How do I save flight data?</emphasis><?linebreak?>
5468 Live telemetry is written to file(s) whenever AltosUI is connected
5469 to the TeleDongle. The file area defaults to ~/TeleMetrum
5470 but is easily changed using the menus in AltosUI. The files that
5471 are written end in '.telem'. The after-flight
5472 data-dumped files will end in .eeprom and represent continuous data
5473 unlike the .telem files that are subject to losses
5474 along the RF data path.
5475 See the above instructions on what and how to save the eeprom stored
5476 data after physically retrieving your altimeter. Make sure to save
5477 the on-board data after each flight; while the TeleMetrum can store
5478 multiple flights, you never know when you'll lose the altimeter...
5482 <title>Notes for Older Software</title>
5485 Before AltosUI was written, using Altus Metrum devices required
5486 some finesse with the Linux command line. There was a limited
5487 GUI tool, ao-view, which provided functionality similar to the
5488 Monitor Flight window in AltosUI, but everything else was a
5489 fairly 80's experience. This appendix includes documentation for
5490 using that software.
5494 Both TeleMetrum and TeleDongle can be directly communicated
5495 with using USB ports. The first thing you should try after getting
5496 both units plugged into to your computer's USB port(s) is to run
5497 'ao-list' from a terminal-window to see what port-device-name each
5498 device has been assigned by the operating system.
5499 You will need this information to access the devices via their
5500 respective on-board firmware and data using other command line
5501 programs in the AltOS software suite.
5504 TeleMini can be communicated with through a TeleDongle device
5505 over the radio link. When first booted, TeleMini listens for a
5506 TeleDongle device and if it receives a packet, it goes into
5507 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be
5508 launched. The easiest way to get it talking is to start the
5509 communication link on the TeleDongle and the power up the
5513 To access the device's firmware for configuration you need a terminal
5514 program such as you would use to talk to a modem. The software
5515 authors prefer using the program 'cu' which comes from the UUCP package
5516 on most Unix-like systems such as Linux. An example command line for
5517 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
5518 indicated from running the
5519 ao-list program. Another reasonable terminal program for Linux is
5520 'cutecom'. The default 'escape'
5521 character used by CU (i.e. the character you use to
5522 issue commands to cu itself instead of sending the command as input
5523 to the connected device) is a '~'. You will need this for use in
5524 only two different ways during normal operations. First is to exit
5525 the program by sending a '~.' which is called a 'escape-disconnect'
5526 and allows you to close-out from 'cu'. The
5527 second use will be outlined later.
5530 All of the Altus Metrum devices share the concept of a two level
5531 command set in their firmware.
5532 The first layer has several single letter commands. Once
5533 you are using 'cu' (or 'cutecom') sending (typing) a '?'
5534 returns a full list of these
5535 commands. The second level are configuration sub-commands accessed
5536 using the 'c' command, for
5537 instance typing 'c?' will give you this second level of commands
5538 (all of which require the
5539 letter 'c' to access). Please note that most configuration options
5540 are stored only in Flash memory; TeleDongle doesn't provide any storage
5541 for these options and so they'll all be lost when you unplug it.
5544 Try setting these configuration ('c' or second level menu) values. A good
5545 place to start is by setting your call sign. By default, the boards
5546 use 'N0CALL' which is cute, but not exactly legal!
5547 Spend a few minutes getting comfortable with the units, their
5548 firmware, and 'cu' (or possibly 'cutecom').
5549 For instance, try to send
5550 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
5551 Verify you can connect and disconnect from the units while in your
5552 terminal program by sending the escape-disconnect mentioned above.
5555 To set the radio frequency, use the 'c R' command to specify the
5556 radio transceiver configuration parameter. This parameter is computed
5557 using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
5558 the standard calibration reference frequency, 'S', (normally 434.550MHz):
5562 Round the result to the nearest integer value.
5563 As with all 'c' sub-commands, follow this with a 'c w' to write the
5564 change to the parameter block in the on-board flash on
5565 your altimeter board if you want the change to stay in place across reboots.
5568 To set the apogee delay, use the 'c d' command.
5569 As with all 'c' sub-commands, follow this with a 'c w' to write the
5570 change to the parameter block in the on-board DataFlash chip.
5573 To set the main deployment altitude, use the 'c m' command.
5574 As with all 'c' sub-commands, follow this with a 'c w' to write the
5575 change to the parameter block in the on-board DataFlash chip.
5578 To calibrate the radio frequency, connect the UHF antenna port to a
5579 frequency counter, set the board to 434.550MHz, and use the 'C'
5580 command to generate a CW carrier. Wait for the transmitter temperature
5581 to stabilize and the frequency to settle down.
5582 Then, divide 434.550 MHz by the
5583 measured frequency and multiply by the current radio cal value show
5584 in the 'c s' command. For an unprogrammed board, the default value
5585 is 1186611 for cc1111 based products and 7119667 for cc1120
5586 based products. Take the resulting integer and program it using the 'c f'
5587 command. Testing with the 'C' command again should show a carrier
5588 within a few tens of Hertz of the intended frequency.
5589 As with all 'c' sub-commands, follow this with a 'c w' to write the
5590 change to the configuration memory.
5593 Note that the 'reboot' command, which is very useful on the altimeters,
5594 will likely just cause problems with the dongle. The *correct* way
5595 to reset the dongle is just to unplug and re-plug it.
5598 A fun thing to do at the launch site and something you can do while
5599 learning how to use these units is to play with the radio link access
5600 between an altimeter and the TeleDongle. Be aware that you *must* create
5601 some physical separation between the devices, otherwise the link will
5602 not function due to signal overload in the receivers in each device.
5605 Now might be a good time to take a break and read the rest of this
5606 manual, particularly about the two “modes” that the altimeters
5607 can be placed in. TeleMetrum uses the position of the device when booting
5608 up will determine whether the unit is in “pad” or “idle” mode. TeleMini
5609 enters “idle” mode when it receives a command packet within the first 5 seconds
5610 of being powered up, otherwise it enters “pad” mode.
5613 You can access an altimeter in idle mode from the TeleDongle's USB
5614 connection using the radio link
5615 by issuing a 'p' command to the TeleDongle. Practice connecting and
5616 disconnecting ('~~' while using 'cu') from the altimeter. If
5617 you cannot escape out of the “p” command, (by using a '~~' when in
5618 CU) then it is likely that your kernel has issues. Try a newer version.
5621 Using this radio link allows you to configure the altimeter, test
5622 fire e-matches and igniters from the flight line, check pyro-match
5623 continuity and so forth. You can leave the unit turned on while it
5624 is in 'idle mode' and then place the
5625 rocket vertically on the launch pad, walk away and then issue a
5626 reboot command. The altimeter will reboot and start sending data
5627 having changed to the “pad” mode. If the TeleDongle is not receiving
5628 this data, you can disconnect 'cu' from the TeleDongle using the
5629 procedures mentioned above and THEN connect to the TeleDongle from
5630 inside 'ao-view'. If this doesn't work, disconnect from the
5631 TeleDongle, unplug it, and try again after plugging it back in.
5634 In order to reduce the chance of accidental firing of pyrotechnic
5635 charges, the command to fire a charge is intentionally somewhat
5636 difficult to type, and the built-in help is slightly cryptic to
5637 prevent accidental echoing of characters from the help text back at
5638 the board from firing a charge. The command to fire the apogee
5639 drogue charge is 'i DoIt drogue' and the command to fire the main
5640 charge is 'i DoIt main'.
5643 On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
5644 and 'ao-view' will both auditorily announce and visually indicate
5646 Now you can launch knowing that you have a good data path and
5647 good satellite lock for flight data and recovery. Remember
5648 you MUST tell ao-view to connect to the TeleDongle explicitly in
5649 order for ao-view to be able to receive data.
5652 The altimeters provide RDF (radio direction finding) tones on
5653 the pad, during descent and after landing. These can be used to
5654 locate the rocket using a directional antenna; the signal
5655 strength providing an indication of the direction from receiver to rocket.
5658 TeleMetrum also provides GPS tracking data, which can further simplify
5659 locating the rocket once it has landed. (The last good GPS data
5660 received before touch-down will be on the data screen of 'ao-view'.)
5663 Once you have recovered the rocket you can download the eeprom
5664 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
5665 either a USB cable or over the radio link using TeleDongle.
5666 And by following the man page for 'ao-postflight' you can create
5667 various data output reports, graphs, and even KML data to see the
5668 flight trajectory in Google-earth. (Moving the viewing angle making
5669 sure to connect the yellow lines while in Google-earth is the proper
5673 As for ao-view.... some things are in the menu but don't do anything
5674 very useful. The developers have stopped working on ao-view to focus
5675 on a new, cross-platform ground station program. So ao-view may or
5676 may not be updated in the future. Mostly you just use
5677 the Log and Device menus. It has a wonderful display of the incoming
5678 flight data and I am sure you will enjoy what it has to say to you
5679 once you enable the voice output!
5683 <title>Drill Templates</title>
5685 These images, when printed, provide precise templates for the
5686 mounting holes in Altus Metrum flight computers
5689 <title>TeleMega template</title>
5691 TeleMega has overall dimensions of 1.250 x 3.250 inches, and
5692 the mounting holes are sized for use with 4-40 or M3 screws.
5695 <mediaobject id="TeleMegaTemplate">
5697 <imagedata format="SVG" fileref="telemega.svg"
5698 scalefit="0" scale="100" align="center" />
5704 <title>EasyMega template</title>
5706 EasyMega has overall dimensions of 1.250 x 2.250 inches, and
5707 the mounting holes are sized for use with 4-40 or M3 screws.
5710 <mediaobject id="EasyMegaTemplate">
5712 <imagedata format="SVG" fileref="easymega.svg"
5713 scalefit="0" scale="100" align="center" />
5719 <title>TeleMetrum template</title>
5721 TeleMetrum has overall dimensions of 1.000 x 2.750 inches, and the
5722 mounting holes are sized for use with 4-40 or M3 screws.
5725 <mediaobject id="TeleMetrumTemplate">
5727 <imagedata format="SVG" fileref="telemetrum.svg"
5728 scalefit="0" scale="100" align="center" />
5734 <title>TeleMini v2/EasyMini template</title>
5736 TeleMini v2 and EasyMini have overall dimensions of 0.800 x 1.500 inches, and the
5737 mounting holes are sized for use with 4-40 or M3 screws.
5740 <mediaobject id="MiniTemplate">
5742 <imagedata format="SVG" fileref="easymini.svg"
5743 scalefit="0" scale="100" align="center" />
5749 <title>TeleMini v1 template</title>
5751 TeleMini has overall dimensions of 0.500 x 1.500 inches, and the
5752 mounting holes are sized for use with 2-56 or M2 screws.
5755 <mediaobject id="TeleMiniTemplate">
5757 <imagedata format="SVG" fileref="telemini.svg"
5758 scalefit="0" scale="100" align="center" />
5765 <title>Calibration</title>
5767 There are only two calibrations required for TeleMetrum and
5768 TeleMega, and only one for EasyMega, TeleDongle, TeleMini and EasyMini.
5769 All boards are shipped from the factory pre-calibrated, but
5770 the procedures are documented here in case they are ever
5771 needed. Re-calibration is not supported by AltosUI, you must
5772 connect to the board with a serial terminal program and
5773 interact directly with the on-board command interpreter to
5777 <title>Radio Frequency</title>
5779 The radio frequency is synthesized from a clock based on the
5780 crystal on the board. The actual frequency of this oscillator
5781 must be measured to generate a calibration constant. While our
5783 bandwidth is wide enough to allow boards to communicate even when
5784 their oscillators are not on exactly the same frequency, performance
5785 is best when they are closely matched.
5786 Radio frequency calibration requires a calibrated frequency counter.
5787 Fortunately, once set, the variation in frequency due to aging and
5788 temperature changes is small enough that re-calibration by customers
5789 should generally not be required.
5792 To calibrate the radio frequency, connect the UHF antenna
5793 port to a frequency counter, set the board to 434.550MHz,
5794 and use the 'C' command in the on-board command interpreter
5795 to generate a CW carrier. For USB-enabled boards, this is
5796 best done over USB. For TeleMini v1, note that the only way
5797 to escape the 'C' command is via power cycle since the board
5798 will no longer be listening for commands once it starts
5799 generating a CW carrier.
5802 Wait for the transmitter temperature to stabilize and the frequency
5803 to settle down. Then, divide 434.550 MHz by the
5804 measured frequency and multiply by the current radio cal value show
5805 in the 'c s' command. For an unprogrammed board, the default value
5806 is 1186611. Take the resulting integer and program it using the 'c f'
5807 command. Testing with the 'C' command again should show a carrier
5808 within a few tens of Hertz of the intended frequency.
5809 As with all 'c' sub-commands, follow this with a 'c w' to write the
5810 change to the parameter block in the on-board storage chip.
5813 Note that any time you re-do the radio frequency calibration, the
5814 radio frequency is reset to the default 434.550 Mhz. If you want
5815 to use another frequency, you will have to set that again after
5816 calibration is completed.
5820 <title>TeleMetrum, TeleMega and EasyMega Accelerometers</title>
5822 While barometric sensors are factory-calibrated,
5823 accelerometers are not, and so each must be calibrated once
5824 installed in a flight computer. Explicitly calibrating the
5825 accelerometers also allows us to load any compatible device.
5826 We perform a two-point calibration using gravity.
5829 To calibrate the acceleration sensor, use the 'c a 0' command. You
5830 will be prompted to orient the board vertically with the UHF antenna
5831 up and press a key, then to orient the board vertically with the
5832 UHF antenna down and press a key. Note that the accuracy of this
5833 calibration depends primarily on how perfectly vertical and still
5834 the board is held during the cal process. As with all 'c'
5835 sub-commands, follow this with a 'c w' to write the
5836 change to the parameter block in the on-board DataFlash chip.
5839 The +1g and -1g calibration points are included in each telemetry
5840 frame and are part of the header stored in onboard flash to be
5841 downloaded after flight. We always store and return raw ADC
5842 samples for each sensor... so nothing is permanently “lost” or
5843 “damaged” if the calibration is poor.
5846 In the unlikely event an accel cal goes badly, it is possible
5847 that TeleMetrum, TeleMega or EasyMega may always come up in 'pad mode'
5848 and as such not be listening to either the USB or radio link.
5849 If that happens, there is a special hook in the firmware to
5850 force the board back in to 'idle mode' so you can re-do the
5851 cal. To use this hook, you just need to ground the SPI clock
5852 pin at power-on. This pin is available as pin 2 on the 8-pin
5853 companion connector, and pin 1 is ground. So either
5854 carefully install a fine-gauge wire jumper between the two
5855 pins closest to the index hole end of the 8-pin connector, or
5856 plug in the programming cable to the 8-pin connector and use
5857 a small screwdriver or similar to short the two pins closest
5858 to the index post on the 4-pin end of the programming cable,
5859 and power up the board. It should come up in 'idle mode'
5860 (two beeps), allowing a re-cal.
5865 <title>Igniter Current</title>
5867 The question "how much igniter current can Altus Metrum products
5868 handle?" comes up fairly frequently. The short answer is "more than
5869 you're likely to need", the remainder of this appendix provides a
5873 <title>Current Products</title>
5875 The FET switches we're using on all of our current products that
5876 have pyro channels are the Vishay Siliconix Si7232DN. These parts
5877 have exceptionally low Rds(on) values, better than 0.02 ohms! That
5878 means they aren't making a lot of heat... and the limit on current
5879 is "package limited", meaning it's all about how much you can heat
5880 the die before something breaks.
5883 Cutting to the chase, the Si7232DN specs are 25 amps <emphasis>continuous</emphasis> at
5884 20V at a temperature of 25C. In pulsed mode, they're rated for 40A.
5885 However, those specs are a little mis-leading because it really is
5886 all about the heat generated... you can get something like 85A
5887 through one briefly. Note that a typical commercial e-match only
5888 needed about 13 microseconds to fire in tests on my bench a couple
5892 So a great plan is to use something like an e-match as the initiator
5893 and build up pyrogen(s) as required to actually light what you're
5894 trying to light... But if you want to use a high-current igniter,
5895 we can probably handle it!
5899 <title>Version 1 Products</title>
5901 The FET switches used on TeleMetrum v1 and TeleMini v1 products
5902 were Fairchild FDS9926A. The Rds(on) values under our operating
5903 conditions are on the order of 0.04 ohms. These parts were rated
5904 for a continuous current-carrying capacity of 6.5A, and a pulsed
5905 current capacity of 20A.
5908 As with the more modern parts, the real limit is based on the heat
5909 generated in the part during the firing interval. So, while the
5910 specs on these parts aren't as good as the ones we use on current
5911 products, they were still great, and we never had a complaint about
5912 current carrying capacity with any of our v1 boards.
5917 <title>Release Notes</title>
5919 <title>Version 1.6</title>
5921 xmlns:xi="http://www.w3.org/2001/XInclude"
5922 href="release-notes-1.6.xsl"
5923 xpointer="xpointer(/article/*)"/>
5926 <title>Version 1.5</title>
5928 xmlns:xi="http://www.w3.org/2001/XInclude"
5929 href="release-notes-1.5.xsl"
5930 xpointer="xpointer(/article/*)"/>
5933 <title>Version 1.4.1</title>
5935 xmlns:xi="http://www.w3.org/2001/XInclude"
5936 href="release-notes-1.4.1.xsl"
5937 xpointer="xpointer(/article/*)"/>
5940 <title>Version 1.4</title>
5942 xmlns:xi="http://www.w3.org/2001/XInclude"
5943 href="release-notes-1.4.xsl"
5944 xpointer="xpointer(/article/*)"/>
5947 <title>Version 1.3.2</title>
5949 xmlns:xi="http://www.w3.org/2001/XInclude"
5950 href="release-notes-1.3.2.xsl"
5951 xpointer="xpointer(/article/*)"/>
5954 <title>Version 1.3.1</title>
5956 xmlns:xi="http://www.w3.org/2001/XInclude"
5957 href="release-notes-1.3.1.xsl"
5958 xpointer="xpointer(/article/*)"/>
5961 <title>Version 1.3</title>
5963 xmlns:xi="http://www.w3.org/2001/XInclude"
5964 href="release-notes-1.3.xsl"
5965 xpointer="xpointer(/article/*)"/>
5968 <title>Version 1.2.1</title>
5970 xmlns:xi="http://www.w3.org/2001/XInclude"
5971 href="release-notes-1.2.1.xsl"
5972 xpointer="xpointer(/article/*)"/>
5975 <title>Version 1.2</title>
5977 xmlns:xi="http://www.w3.org/2001/XInclude"
5978 href="release-notes-1.2.xsl"
5979 xpointer="xpointer(/article/*)"/>
5982 <title>Version 1.1.1</title>
5984 xmlns:xi="http://www.w3.org/2001/XInclude"
5985 href="release-notes-1.1.1.xsl"
5986 xpointer="xpointer(/article/*)"/>
5989 <title>Version 1.1</title>
5991 xmlns:xi="http://www.w3.org/2001/XInclude"
5992 href="release-notes-1.1.xsl"
5993 xpointer="xpointer(/article/*)"/>
5996 <title>Version 1.0.1</title>
5998 xmlns:xi="http://www.w3.org/2001/XInclude"
5999 href="release-notes-1.0.1.xsl"
6000 xpointer="xpointer(/article/*)"/>
6003 <title>Version 0.9.2</title>
6005 xmlns:xi="http://www.w3.org/2001/XInclude"
6006 href="release-notes-0.9.2.xsl"
6007 xpointer="xpointer(/article/*)"/>
6010 <title>Version 0.9</title>
6012 xmlns:xi="http://www.w3.org/2001/XInclude"
6013 href="release-notes-0.9.xsl"
6014 xpointer="xpointer(/article/*)"/>
6017 <title>Version 0.8</title>
6019 xmlns:xi="http://www.w3.org/2001/XInclude"
6020 href="release-notes-0.8.xsl"
6021 xpointer="xpointer(/article/*)"/>
6024 <title>Version 0.7.1</title>
6026 xmlns:xi="http://www.w3.org/2001/XInclude"
6027 href="release-notes-0.7.1.xsl"
6028 xpointer="xpointer(/article/*)"/>
6033 <!-- LocalWords: Altusmetrum
projects / fw / altos / blob