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5 <title>The Altus Metrum System</title>
6 <subtitle>An Owner's Manual for Altus Metrum Rocketry Electronics</subtitle>
9 <firstname>Bdale</firstname>
10 <surname>Garbee</surname>
13 <firstname>Keith</firstname>
14 <surname>Packard</surname>
17 <firstname>Bob</firstname>
18 <surname>Finch</surname>
21 <firstname>Anthony</firstname>
22 <surname>Towns</surname>
26 <holder>Bdale Garbee and Keith Packard</holder>
30 This document is released under the terms of the
31 <ulink url="http://creativecommons.org/licenses/by-sa/3.0/">
32 Creative Commons ShareAlike 3.0
39 <revnumber>1.3</revnumber>
40 <date>12 November 2013</date>
42 Updated for software version 1.3. Version 1.3 adds support
43 for TeleMega, TeleMetrum v2.0, TeleMini v2.0 and EasyMini
44 and fixes bugs in AltosUI and the AltOS firmware.
48 <revnumber>1.2.1</revnumber>
49 <date>21 May 2013</date>
51 Updated for software version 1.2. Version 1.2 adds support
52 for TeleBT and AltosDroid. It also adds a few minor features
53 and fixes bugs in AltosUI and the AltOS firmware.
57 <revnumber>1.2</revnumber>
58 <date>18 April 2013</date>
60 Updated for software version 1.2. Version 1.2 adds support
61 for MicroPeak and the MicroPeak USB interface.
65 <revnumber>1.1.1</revnumber>
66 <date>16 September 2012</date>
68 Updated for software version 1.1.1 Version 1.1.1 fixes a few
69 bugs found in version 1.1.
73 <revnumber>1.1</revnumber>
74 <date>13 September 2012</date>
76 Updated for software version 1.1. Version 1.1 has new
77 features but is otherwise compatible with version 1.0.
81 <revnumber>1.0</revnumber>
82 <date>24 August 2011</date>
84 Updated for software version 1.0. Note that 1.0 represents a
85 telemetry format change, meaning both ends of a link
86 (TeleMetrum/TeleMini and TeleDongle) must be updated or
87 communications will fail.
91 <revnumber>0.9</revnumber>
92 <date>18 January 2011</date>
94 Updated for software version 0.9. Note that 0.9 represents a
95 telemetry format change, meaning both ends of a link (TeleMetrum and
96 TeleDongle) must be updated or communications will fail.
100 <revnumber>0.8</revnumber>
101 <date>24 November 2010</date>
102 <revremark>Updated for software version 0.8 </revremark>
107 <title>Acknowledgments</title>
109 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing “The
110 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
111 Kit” which formed the basis of the original Getting Started chapter
112 in this manual. Bob was one of our first customers for a production
113 TeleMetrum, and his continued enthusiasm and contributions
114 are immensely gratifying and highly appreciated!
117 And thanks to Anthony (AJ) Towns for major contributions including
118 the AltosUI graphing and site map code and associated documentation.
119 Free software means that our customers and friends can become our
120 collaborators, and we certainly appreciate this level of
124 Have fun using these products, and we hope to meet all of you
125 out on the rocket flight line somewhere.
128 NAR #87103, TRA #12201
130 Keith Packard, KD7SQG
131 NAR #88757, TRA #12200
136 <title>Introduction and Overview</title>
138 Welcome to the Altus Metrum community! Our circuits and software reflect
139 our passion for both hobby rocketry and Free Software. We hope their
140 capabilities and performance will delight you in every way, but by
141 releasing all of our hardware and software designs under open licenses,
142 we also hope to empower you to take as active a role in our collective
146 The first device created for our community was TeleMetrum, a dual
147 deploy altimeter with fully integrated GPS and radio telemetry
148 as standard features, and a “companion interface” that will
149 support optional capabilities in the future. The latest version
150 of TeleMetrum, v2.0, has all of the same features but with
151 improved sensors and radio to offer increased performance.
154 Our second device was TeleMini, a dual deploy altimeter with
155 radio telemetry and radio direction finding. The first version
156 of this device was only 13mm by 38mm (½ inch by 1½ inches) and
157 could fit easily in an 18mm air-frame. The latest version, v2.0,
158 includes a beeper, USB data download and extended on-board
159 flight logging, along with an improved barometric sensor.
162 TeleMega is our most sophisticated device, including six pyro
163 channels (four of which are fully programmable), integrated GPS,
164 integrated gyroscopes for staging/air-start inhibit and high
165 performance telemetry.
168 EasyMini is a dual-deploy altimeter with logging and built-in
172 TeleDongle was our first ground station, providing a USB to RF
173 interfaces for communicating with the altimeters. Combined with
174 your choice of antenna and notebook computer, TeleDongle and our
175 associated user interface software form a complete ground
176 station capable of logging and displaying in-flight telemetry,
177 aiding rocket recovery, then processing and archiving flight
178 data for analysis and review.
181 For a slightly more portable ground station experience that also
182 provides direct rocket recovery support, TeleBT offers flight
183 monitoring and data logging using a Bluetooth™ connection between
184 the receiver and an Android device that has the AltosDroid
185 application installed from the Google Play store.
188 More products will be added to the Altus Metrum family over time, and
189 we currently envision that this will be a single, comprehensive manual
190 for the entire product family.
194 <title>Getting Started</title>
196 The first thing to do after you check the inventory of parts in your
197 “starter kit” is to charge the battery.
200 For TeleMetrum and TeleMega, the battery can be charged by plugging it into the
201 corresponding socket of the device and then using the USB
202 cable to plug the flight computer into your computer's USB socket. The
203 on-board circuitry will charge the battery whenever it is plugged
204 in, because the on-off switch does NOT control the
208 On TeleMetrum v1 boards, when the GPS chip is initially
209 searching for satellites, TeleMetrum will consume more current
210 than it pulls from the USB port, so the battery must be
211 attached in order to get satellite lock. Once GPS is locked,
212 the current consumption goes back down enough to enable charging
213 while running. So it's a good idea to fully charge the battery
214 as your first item of business so there is no issue getting and
215 maintaining satellite lock. The yellow charge indicator led
216 will go out when the battery is nearly full and the charger goes
217 to trickle charge. It can take several hours to fully recharge a
218 deeply discharged battery.
221 TeleMetrum v2.0 and TeleMega use a higher power battery charger,
222 allowing them to charge the battery while running the board at
223 maximum power. When the battery is charging, or when the board
224 is consuming a lot of power, the red LED will be lit. When the
225 battery is fully charged, the green LED will be lit. When the
226 battery is damaged or missing, both LEDs will be lit, which
230 The Lithium Polymer TeleMini and EasyMini battery can be charged by
231 disconnecting it from the board and plugging it into a
232 standalone battery charger such as the LipoCharger product
233 included in TeleMini Starter Kits, and connecting that via a USB
234 cable to a laptop or other USB power source.
237 You can also choose to use another battery with TeleMini v2.0
238 and EasyMini, anything supplying between 4 and 12 volts should
239 work fine (like a standard 9V battery), but if you are planning
240 to fire pyro charges, ground testing is required to verify that
241 the battery supplies enough current to fire your chosen e-matches.
244 The other active device in the starter kit is the TeleDongle USB to
245 RF interface. If you plug it in to your Mac or Linux computer it should
246 “just work”, showing up as a serial port device. Windows systems need
247 driver information that is part of the AltOS download to know that the
248 existing USB modem driver will work. We therefore recommend installing
249 our software before plugging in TeleDongle if you are using a Windows
250 computer. If you are using an older version of Linux and are having
251 problems, try moving to a fresher kernel (2.6.33 or newer).
254 Next you should obtain and install the AltOS software. The AltOS
255 distribution includes the AltosUI ground station program, current
257 images for all of the hardware, and a number of standalone
258 utilities that are rarely needed. Pre-built binary packages are
259 available for Linux, Microsoft Windows, and recent MacOSX
260 versions. Full source code and build instructions are also
261 available. The latest version may always be downloaded from
262 <ulink url="http://altusmetrum.org/AltOS"/>.
265 If you're using a TeleBT instead of the TeleDongle, you'll want to
266 install the AltosDroid application from the Google Play store on an
267 Android device. You don't need a data plan to use AltosDroid, but
268 without network access, the Map view will be less useful as it
269 won't contain any map data. You can also use TeleBT connected
270 over USB with your laptop computer; it acts exactly like a
271 TeleDongle. Anywhere this manual talks about TeleDongle, you can
272 also read that as 'and TeleBT when connected via USB'.
276 <title>Handling Precautions</title>
278 All Altus Metrum products are sophisticated electronic devices.
279 When handled gently and properly installed in an air-frame, they
280 will deliver impressive results. However, as with all electronic
281 devices, there are some precautions you must take.
284 The Lithium Polymer rechargeable batteries have an
285 extraordinary power density. This is great because we can fly with
286 much less battery mass than if we used alkaline batteries or previous
287 generation rechargeable batteries... but if they are punctured
288 or their leads are allowed to short, they can and will release their
290 Thus we recommend that you take some care when handling our batteries
291 and consider giving them some extra protection in your air-frame. We
292 often wrap them in suitable scraps of closed-cell packing foam before
293 strapping them down, for example.
296 The barometric sensors used on all of our flight computers are
297 sensitive to sunlight. In normal mounting situations, the baro sensor
298 and all of the other surface mount components
299 are “down” towards whatever the underlying mounting surface is, so
300 this is not normally a problem. Please consider this when designing an
301 installation in an air-frame with a see-through plastic payload bay. It
302 is particularly important to
303 consider this with TeleMini v1.0, both because the baro sensor is on the
304 “top” of the board, and because many model rockets with payload bays
305 use clear plastic for the payload bay! Replacing these with an opaque
306 cardboard tube, painting them, or wrapping them with a layer of masking
307 tape are all reasonable approaches to keep the sensor out of direct
311 The barometric sensor sampling port must be able to “breathe”,
312 both by not being covered by foam or tape or other materials that might
313 directly block the hole on the top of the sensor, and also by having a
314 suitable static vent to outside air.
317 As with all other rocketry electronics, Altus Metrum altimeters must
318 be protected from exposure to corrosive motor exhaust and ejection
323 <title>Altus Metrum Hardware</title>
325 <title>Overview</title>
327 Here's the full set of Altus Metrum products, both in
328 production and retired.
331 <title>Altus Metrum Electronics</title>
332 <tgroup cols='8' align='center' colsep='1' rowsep='1'>
333 <colspec align='center' colwidth='*' colname='Device'/>
334 <colspec align='center' colwidth='*' colname='Barometer'/>
335 <colspec align='center' colwidth='*' colname='Z-axis accelerometer'/>
336 <colspec align='center' colwidth='*' colname='GPS'/>
337 <colspec align='center' colwidth='*' colname='3D sensors'/>
338 <colspec align='center' colwidth='*' colname='Storage'/>
339 <colspec align='center' colwidth='*' colname='RF'/>
340 <colspec align='center' colwidth='*' colname='Battery'/>
343 <entry align='center'>Device</entry>
344 <entry align='center'>Barometer</entry>
345 <entry align='center'>Z-axis accelerometer</entry>
346 <entry align='center'>GPS</entry>
347 <entry align='center'>3D sensors</entry>
348 <entry align='center'>Storage</entry>
349 <entry align='center'>RF Output</entry>
350 <entry align='center'>Battery</entry>
355 <entry>TeleMetrum v1.0</entry>
356 <entry><para>MP3H6115 10km (33k')</para></entry>
357 <entry><para>MMA2202 50g</para></entry>
358 <entry>SkyTraq</entry>
365 <entry>TeleMetrum v1.1</entry>
366 <entry><para>MP3H6115 10km (33k')</para></entry>
367 <entry><para>MMA2202 50g</para></entry>
368 <entry>SkyTraq</entry>
375 <entry>TeleMetrum v1.2</entry>
376 <entry><para>MP3H6115 10km (33k')</para></entry>
377 <entry><para>ADXL78 70g</para></entry>
378 <entry>SkyTraq</entry>
385 <entry>TeleMetrum v2.0</entry>
386 <entry><para>MS5607 30km (100k')</para></entry>
387 <entry><para>MMA6555 102g</para></entry>
388 <entry>uBlox Max-7Q</entry>
395 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
396 <entry><para>MP3H6115 10km (33k')</para></entry>
405 <entry>TeleMini <?linebreak?>v2.0</entry>
406 <entry><para>MS5607 30km (100k')</para></entry>
412 <entry>3.7-12V</entry>
415 <entry>EasyMini <?linebreak?>v1.0</entry>
416 <entry><para>MS5607 30km (100k')</para></entry>
422 <entry>3.7-12V</entry>
425 <entry>TeleMega <?linebreak?>v1.0</entry>
426 <entry><para>MS5607 30km (100k')</para></entry>
427 <entry><para>MMA6555 102g</para></entry>
428 <entry>uBlox Max-7Q</entry>
429 <entry><para>MPU6000 HMC5883</para></entry>
438 <title>Altus Metrum Boards</title>
439 <tgroup cols='6' align='center' colsep='1' rowsep='1'>
440 <colspec align='center' colwidth='*' colname='Device'/>
441 <colspec align='center' colwidth='*' colname='Connectors'/>
442 <colspec align='center' colwidth='*' colname='Screw Terminals'/>
443 <colspec align='center' colwidth='*' colname='Width'/>
444 <colspec align='center' colwidth='*' colname='Length'/>
445 <colspec align='center' colwidth='*' colname='Tube Size'/>
448 <entry align='center'>Device</entry>
449 <entry align='center'>Connectors</entry>
450 <entry align='center'>Screw Terminals</entry>
451 <entry align='center'>Width</entry>
452 <entry align='center'>Length</entry>
453 <entry align='center'>Tube Size</entry>
458 <entry>TeleMetrum</entry>
462 Companion<?linebreak?>
466 <entry><para>Apogee pyro <?linebreak?>Main pyro <?linebreak?>Switch</para></entry>
467 <entry>1 inch (2.54cm)</entry>
468 <entry>2 ¾ inch (6.99cm)</entry>
469 <entry>29mm coupler</entry>
472 <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
479 Apogee pyro <?linebreak?>
482 <entry>½ inch (1.27cm)</entry>
483 <entry>1½ inch (3.81cm)</entry>
484 <entry>18mm coupler</entry>
487 <entry>TeleMini <?linebreak?>v2.0</entry>
495 Apogee pyro <?linebreak?>
496 Main pyro <?linebreak?>
497 Battery <?linebreak?>
500 <entry>0.8 inch (2.03cm)</entry>
501 <entry>1½ inch (3.81cm)</entry>
502 <entry>24mm coupler</entry>
505 <entry>EasyMini</entry>
512 Apogee pyro <?linebreak?>
513 Main pyro <?linebreak?>
514 Battery <?linebreak?>
517 <entry>0.8 inch (2.03cm)</entry>
518 <entry>1½ inch (3.81cm)</entry>
519 <entry>24mm coupler</entry>
522 <entry>TeleMega</entry>
526 Companion<?linebreak?>
531 Apogee pyro <?linebreak?>
532 Main pyro<?linebreak?>
533 Pyro A-D<?linebreak?>
537 <entry>1¼ inch (3.18cm)</entry>
538 <entry>3¼ inch (8.26cm)</entry>
539 <entry>38mm coupler</entry>
546 <title>TeleMetrum</title>
548 TeleMetrum is a 1 inch by 2¾ inch circuit board. It was designed to
549 fit inside coupler for 29mm air-frame tubing, but using it in a tube that
550 small in diameter may require some creativity in mounting and wiring
551 to succeed! The presence of an accelerometer means TeleMetrum should
552 be aligned along the flight axis of the airframe, and by default the ¼
553 wave UHF wire antenna should be on the nose-cone end of the board. The
554 antenna wire is about 7 inches long, and wiring for a power switch and
555 the e-matches for apogee and main ejection charges depart from the
556 fin can end of the board, meaning an ideal “simple” avionics
557 bay for TeleMetrum should have at least 10 inches of interior length.
561 <title>TeleMini</title>
563 TeleMini v1.0 is ½ inches by 1½ inches. It was
564 designed to fit inside an 18mm air-frame tube, but using it in
565 a tube that small in diameter may require some creativity in
566 mounting and wiring to succeed! Since there is no
567 accelerometer, TeleMini can be mounted in any convenient
568 orientation. The default ¼ wave UHF wire antenna attached to
569 the center of one end of the board is about 7 inches long. Two
570 wires for the power switch are connected to holes in the
571 middle of the board. Screw terminals for the e-matches for
572 apogee and main ejection charges depart from the other end of
573 the board, meaning an ideal “simple” avionics bay for TeleMini
574 should have at least 9 inches of interior length.
577 TeleMini v2.0 is 0.8 inches by 1½ inches. It adds more
578 on-board data logging memory, a built-in USB connector and
579 screw terminals for the battery and power switch. The larger
580 board fits in a 24mm coupler. There's also a battery connector
581 for a LiPo battery if you want to use one of those.
585 <title>EasyMini</title>
587 EasyMini is built on a 0.8 inch by 1½ inch circuit board. It's
588 designed to fit in a 24mm coupler tube. The connectors and
589 screw terminals match TeleMini v2.0, so you can easily swap between
590 EasyMini and TeleMini.
594 <title>TeleMega</title>
596 TeleMega is a 1¼ inch by 3¼ inch circuit board. It was
597 designed to easily fit in a 38mm coupler. Like TeleMetrum,
598 TeleMega has an accelerometer and so it must be mounted so that
599 the board is aligned with the flight axis. It can be mounted
600 either antenna up or down.
604 <title>Flight Data Recording</title>
606 Each flight computer logs data at 100 samples per second
607 during ascent and 10 samples per second during descent, except
608 for TeleMini v1.0, which records ascent at 10 samples per
609 second and descent at 1 sample per second. Data are logged to
610 an on-board flash memory part, which can be partitioned into
611 several equal-sized blocks, one for each flight.
614 <title>Data Storage on Altus Metrum altimeters</title>
615 <tgroup cols='4' align='center' colsep='1' rowsep='1'>
616 <colspec align='center' colwidth='*' colname='Device'/>
617 <colspec align='center' colwidth='*' colname='Bytes per sample'/>
618 <colspec align='center' colwidth='*' colname='Total storage'/>
619 <colspec align='center' colwidth='*' colname='Minutes of
623 <entry align='center'>Device</entry>
624 <entry align='center'>Bytes per Sample</entry>
625 <entry align='center'>Total Storage</entry>
626 <entry align='center'>Minutes at Full Rate</entry>
631 <entry>TeleMetrum v1.0</entry>
637 <entry>TeleMetrum v1.1 v1.2</entry>
643 <entry>TeleMetrum v2.0</entry>
649 <entry>TeleMini v1.0</entry>
655 <entry>TeleMini v2.0</entry>
661 <entry>EasyMini</entry>
667 <entry>TeleMega</entry>
676 The on-board flash is partitioned into separate flight logs,
677 each of a fixed maximum size. Increase the maximum size of
678 each log and you reduce the number of flights that can be
679 stored. Decrease the size and you can store more flights.
682 Configuration data is also stored in the flash memory on
683 TeleMetrum v1.x, TeleMini and EasyMini. This consumes 64kB
684 of flash space. This configuration space is not available
685 for storing flight log data. TeleMetrum v2.0 and TeleMega
686 store configuration data in a bit of eeprom available within
687 the processor chip, leaving that space available in flash for
691 To compute the amount of space needed for a single flight, you
692 can multiply the expected ascent time (in seconds) by 100
693 times bytes-per-sample, multiply the expected descent time (in
694 seconds) by 10 times the bytes per sample and add the two
695 together. That will slightly under-estimate the storage (in
696 bytes) needed for the flight. For instance, a TeleMetrum v2.0 flight spending
697 20 seconds in ascent and 150 seconds in descent will take
698 about (20 * 1600) + (150 * 160) = 56000 bytes of storage. You
699 could store dozens of these flights in the on-board flash.
702 The default size allows for several flights on each flight
703 computer, except for TeleMini v1.0, which only holds data for a
704 single flight. You can adjust the size.
707 Altus Metrum flight computers will not overwrite existing
708 flight data, so be sure to download flight data and erase it
709 from the flight computer before it fills up. The flight
710 computer will still successfully control the flight even if it
711 cannot log data, so the only thing you will lose is the data.
715 <title>Installation</title>
717 A typical installation involves attaching
718 only a suitable battery, a single pole switch for
719 power on/off, and two pairs of wires connecting e-matches for the
720 apogee and main ejection charges. All Altus Metrum products are
721 designed for use with single-cell batteries with 3.7 volts
722 nominal. TeleMini v2.0 and EasyMini may also be used with other
723 batteries as long as they supply between 4 and 12 volts.
726 The battery connectors are a standard 2-pin JST connector and
727 match batteries sold by Spark Fun. These batteries are
728 single-cell Lithium Polymer batteries that nominally provide 3.7
729 volts. Other vendors sell similar batteries for RC aircraft
730 using mating connectors, however the polarity for those is
731 generally reversed from the batteries used by Altus Metrum
732 products. In particular, the Tenergy batteries supplied for use
733 in Featherweight flight computers are not compatible with Altus
734 Metrum flight computers or battery chargers. <emphasis>Check
735 polarity and voltage before connecting any battery not purchased
736 from Altus Metrum or Spark Fun.</emphasis>
739 By default, we use the unregulated output of the battery directly
740 to fire ejection charges. This works marvelously with standard
741 low-current e-matches like the J-Tek from MJG Technologies, and with
742 Quest Q2G2 igniters. However, if you want or need to use a separate
743 pyro battery, check out the “External Pyro Battery” section in this
744 manual for instructions on how to wire that up. The altimeters are
745 designed to work with an external pyro battery of no more than 15 volts.
749 Ejection charges are wired directly to the screw terminal block
750 at the aft end of the altimeter. You'll need a very small straight
751 blade screwdriver for these screws, such as you might find in a
752 jeweler's screwdriver set.
755 Except for TeleMini v1.0, the flight computers also use the
756 screw terminal block for the power switch leads. On TeleMini v1.0,
757 the power switch leads are soldered directly to the board and
758 can be connected directly to a switch.
761 For most air-frames, the integrated antennas are more than
762 adequate. However, if you are installing in a carbon-fiber or
763 metal electronics bay which is opaque to RF signals, you may need to
764 use off-board external antennas instead. In this case, you can
765 replace the stock UHF antenna wire with an edge-launched SMA connector,
766 and, on TeleMetrum v1, you can unplug the integrated GPS
767 antenna and select an appropriate off-board GPS antenna with
768 cable terminating in a U.FL connector.
773 <title>System Operation</title>
775 <title>Firmware Modes </title>
777 The AltOS firmware build for the altimeters has two
778 fundamental modes, “idle” and “flight”. Which of these modes
779 the firmware operates in is determined at start up time. For
780 TeleMetrum and TeleMega, which have accelerometers, the mode is
781 controlled by the orientation of the
782 rocket (well, actually the board, of course...) at the time
783 power is switched on. If the rocket is “nose up”, then
784 the flight computer assumes it's on a rail or rod being prepared for
785 launch, so the firmware chooses flight mode. However, if the
786 rocket is more or less horizontal, the firmware instead enters
787 idle mode. Since TeleMini v2.0 and EasyMini don't have an
788 accelerometer we can use to determine orientation, “idle” mode
789 is selected if the board is connected via USB to a computer,
790 otherwise the board enters “flight” mode. TeleMini v1.0
791 selects “idle” mode if it receives a command packet within the
792 first five seconds of operation.
795 At power on, you will hear three beeps or see three flashes
796 (“S” in Morse code for start up) and then a pause while
797 the altimeter completes initialization and self test, and decides
798 which mode to enter next.
801 In flight or “pad” mode, the altimeter engages the flight
802 state machine, goes into transmit-only mode to
803 send telemetry, and waits for launch to be detected.
804 Flight mode is indicated by an “di-dah-dah-dit” (“P” for pad)
805 on the beeper or lights, followed by beeps or flashes
806 indicating the state of the pyrotechnic igniter continuity.
807 One beep/flash indicates apogee continuity, two beeps/flashes
808 indicate main continuity, three beeps/flashes indicate both
809 apogee and main continuity, and one longer “brap” sound or
810 rapidly alternating lights indicates no continuity. For a
811 dual deploy flight, make sure you're getting three beeps or
812 flashes before launching! For apogee-only or motor eject
813 flights, do what makes sense.
816 If idle mode is entered, you will hear an audible “di-dit” or
817 see two short flashes (“I” for idle), and the flight state
818 machine is disengaged, thus no ejection charges will fire.
819 The altimeters also listen for the radio link when in idle
820 mode for requests sent via TeleDongle. Commands can be issued
821 in idle mode over either USB or the radio link
822 equivalently. TeleMini v1.0 only has the radio link. Idle
823 mode is useful for configuring the altimeter, for extracting
824 data from the on-board storage chip after flight, and for
825 ground testing pyro charges.
828 One “neat trick” of particular value when TeleMetrum or TeleMega are used with
829 very large air-frames, is that you can power the board up while the
830 rocket is horizontal, such that it comes up in idle mode. Then you can
831 raise the air-frame to launch position, and issue a 'reset' command
832 via TeleDongle over the radio link to cause the altimeter to reboot and
833 come up in flight mode. This is much safer than standing on the top
834 step of a rickety step-ladder or hanging off the side of a launch
835 tower with a screw-driver trying to turn on your avionics before
839 TeleMini v1.0 is configured solely via the radio link. Of course, that
840 means you need to know the TeleMini radio configuration values
841 or you won't be able to communicate with it. For situations
842 when you don't have the radio configuration values, TeleMini v1.0
843 offers an 'emergency recovery' mode. In this mode, TeleMini is
844 configured as follows:
848 Sets the radio frequency to 434.550MHz
853 Sets the radio calibration back to the factory value.
858 Sets the callsign to N0CALL
863 Does not go to 'pad' mode after five seconds.
869 To get into 'emergency recovery' mode, first find the row of
870 four small holes opposite the switch wiring. Using a short
871 piece of small gauge wire, connect the outer two holes
872 together, then power TeleMini up. Once the red LED is lit,
873 disconnect the wire and the board should signal that it's in
874 'idle' mode after the initial five second startup period.
880 TeleMetrum and TeleMega include a complete GPS receiver. A
881 complete explanation of how GPS works is beyond the scope of
882 this manual, but the bottom line is that the GPS receiver
883 needs to lock onto at least four satellites to obtain a solid
884 3 dimensional position fix and know what time it is.
887 The flight computers provide backup power to the GPS chip any time a
888 battery is connected. This allows the receiver to “warm start” on
889 the launch rail much faster than if every power-on were a GPS
890 “cold start”. In typical operations, powering up
891 on the flight line in idle mode while performing final air-frame
892 preparation will be sufficient to allow the GPS receiver to cold
893 start and acquire lock. Then the board can be powered down during
894 RSO review and installation on a launch rod or rail. When the board
895 is turned back on, the GPS system should lock very quickly, typically
896 long before igniter installation and return to the flight line are
901 <title>Controlling An Altimeter Over The Radio Link</title>
903 One of the unique features of the Altus Metrum system is the
904 ability to create a two way command link between TeleDongle
905 and an altimeter using the digital radio transceivers
906 built into each device. This allows you to interact with the
907 altimeter from afar, as if it were directly connected to the
911 Any operation which can be performed with a flight computer can
912 either be done with the device directly connected to the
913 computer via the USB cable, or through the radio
914 link. TeleMini v1.0 doesn't provide a USB connector and so it is
915 always communicated with over radio. Select the appropriate
916 TeleDongle device when the list of devices is presented and
917 AltosUI will interact with an altimeter over the radio link.
920 One oddity in the current interface is how AltosUI selects the
921 frequency for radio communications. Instead of providing
922 an interface to specifically configure the frequency, it uses
923 whatever frequency was most recently selected for the target
924 TeleDongle device in Monitor Flight mode. If you haven't ever
925 used that mode with the TeleDongle in question, select the
926 Monitor Flight button from the top level UI, and pick the
927 appropriate TeleDongle device. Once the flight monitoring
928 window is open, select the desired frequency and then close it
929 down again. All radio communications will now use that frequency.
934 Save Flight Data—Recover flight data from the rocket without
940 Configure altimeter apogee delays, main deploy heights
941 and additional pyro event conditions
942 to respond to changing launch conditions. You can also
943 'reboot' the altimeter. Use this to remotely enable the
944 flight computer by turning TeleMetrum or TeleMega on in “idle” mode,
945 then once the air-frame is oriented for launch, you can
946 reboot the altimeter and have it restart in pad mode
947 without having to climb the scary ladder.
952 Fire Igniters—Test your deployment charges without snaking
953 wires out through holes in the air-frame. Simply assemble the
954 rocket as if for flight with the apogee and main charges
955 loaded, then remotely command the altimeter to fire the
961 Operation over the radio link for configuring an altimeter, ground
962 testing igniters, and so forth uses the same RF frequencies as flight
963 telemetry. To configure the desired TeleDongle frequency, select
964 the monitor flight tab, then use the frequency selector and
965 close the window before performing other desired radio operations.
968 The flight computers only enable radio commanding in 'idle' mode.
969 TeleMetrum and TeleMega use the accelerometer to detect which orientation they
970 start up in, so make sure you have the flight computer lying horizontally when you turn
971 it on. Otherwise, it will start in 'pad' mode ready for
972 flight, and will not be listening for command packets from TeleDongle.
975 TeleMini listens for a command packet for five seconds after
976 first being turned on, if it doesn't hear anything, it enters
977 'pad' mode, ready for flight and will no longer listen for
978 command packets. The easiest way to connect to TeleMini is to
979 initiate the command and select the TeleDongle device. At this
980 point, the TeleDongle will be attempting to communicate with
981 the TeleMini. Now turn TeleMini on, and it should immediately
982 start communicating with the TeleDongle and the desired
983 operation can be performed.
986 You can monitor the operation of the radio link by watching the
987 lights on the devices. The red LED will flash each time a packet
988 is transmitted, while the green LED will light up on TeleDongle when
989 it is waiting to receive a packet from the altimeter.
993 <title>Ground Testing </title>
995 An important aspect of preparing a rocket using electronic deployment
996 for flight is ground testing the recovery system. Thanks
997 to the bi-directional radio link central to the Altus Metrum system,
998 this can be accomplished in a TeleMega, TeleMetrum or TeleMini equipped rocket
999 with less work than you may be accustomed to with other systems. It
1003 Just prep the rocket for flight, then power up the altimeter
1004 in “idle” mode (placing air-frame horizontal for TeleMetrum or TeleMega, or
1005 selecting the Configure Altimeter tab for TeleMini). This will cause
1006 the firmware to go into “idle” mode, in which the normal flight
1007 state machine is disabled and charges will not fire without
1008 manual command. You can now command the altimeter to fire the apogee
1009 or main charges from a safe distance using your computer and
1010 TeleDongle and the Fire Igniter tab to complete ejection testing.
1014 <title>Radio Link </title>
1016 Our flight computers all incorporate an RF transceiver, but
1017 it's not a full duplex system... each end can only be transmitting or
1018 receiving at any given moment. So we had to decide how to manage the
1022 By design, the altimeter firmware listens for the radio link when
1023 it's in “idle mode”, which
1024 allows us to use the radio link to configure the rocket, do things like
1025 ejection tests, and extract data after a flight without having to
1026 crack open the air-frame. However, when the board is in “flight
1027 mode”, the altimeter only
1028 transmits and doesn't listen at all. That's because we want to put
1029 ultimate priority on event detection and getting telemetry out of
1031 the radio in case the rocket crashes and we aren't able to extract
1035 We don't generally use a 'normal packet radio' mode like APRS
1036 because they're just too inefficient. The GFSK modulation we
1037 use is FSK with the base-band pulses passed through a Gaussian
1038 filter before they go into the modulator to limit the
1039 transmitted bandwidth. When combined with forward error
1040 correction and interleaving, this allows us to have a very
1041 robust 19.2 kilobit data link with only 10-40 milliwatts of
1042 transmit power, a whip antenna in the rocket, and a hand-held
1043 Yagi on the ground. We've had flights to above 21k feet AGL
1044 with great reception, and calculations suggest we should be
1045 good to well over 40k feet AGL with a 5-element yagi on the
1046 ground with our 10mW units and over 100k feet AGL with the
1047 40mW devices. We hope to fly boards to higher altitudes over
1048 time, and would of course appreciate customer feedback on
1049 performance in higher altitude flights!
1052 TeleMetrum v2.0 and TeleMega can send APRS if desired, and the
1053 interval between APRS packets can be configured. As each APRS
1054 packet takes a full second to transmit, we recommend an
1055 interval of at least 5 seconds to avoid consuming too much
1056 battery power or radio channel bandwidth.
1060 <title>Configurable Parameters</title>
1062 Configuring an Altus Metrum altimeter for flight is very
1063 simple. Even on our baro-only TeleMini and EasyMini boards, the use of a Kalman
1064 filter means there is no need to set a “mach delay”. The few
1065 configurable parameters can all be set using AltosUI over USB or
1066 or radio link via TeleDongle.
1069 <title>Radio Frequency</title>
1071 Altus Metrum boards support radio frequencies in the 70cm
1072 band. By default, the configuration interface provides a
1073 list of 10 “standard” frequencies in 100kHz channels starting at
1074 434.550MHz. However, the firmware supports use of
1075 any 50kHz multiple within the 70cm band. At any given
1076 launch, we highly recommend coordinating when and by whom each
1077 frequency will be used to avoid interference. And of course, both
1078 altimeter and TeleDongle must be configured to the same
1079 frequency to successfully communicate with each other.
1083 <title>Apogee Delay</title>
1085 Apogee delay is the number of seconds after the altimeter detects flight
1086 apogee that the drogue charge should be fired. In most cases, this
1087 should be left at the default of 0. However, if you are flying
1088 redundant electronics such as for an L3 certification, you may wish
1089 to set one of your altimeters to a positive delay so that both
1090 primary and backup pyrotechnic charges do not fire simultaneously.
1093 The Altus Metrum apogee detection algorithm fires exactly at
1094 apogee. If you are also flying an altimeter like the
1095 PerfectFlite MAWD, which only supports selecting 0 or 1
1096 seconds of apogee delay, you may wish to set the MAWD to 0
1097 seconds delay and set the TeleMetrum to fire your backup 2
1098 or 3 seconds later to avoid any chance of both charges
1099 firing simultaneously. We've flown several air-frames this
1100 way quite happily, including Keith's successful L3 cert.
1104 <title>Main Deployment Altitude</title>
1106 By default, the altimeter will fire the main deployment charge at an
1107 elevation of 250 meters (about 820 feet) above ground. We think this
1108 is a good elevation for most air-frames, but feel free to change this
1109 to suit. In particular, if you are flying two altimeters, you may
1111 deployment elevation for the backup altimeter to be something lower
1112 than the primary so that both pyrotechnic charges don't fire
1117 <title>Maximum Flight Log</title>
1119 Changing this value will set the maximum amount of flight
1120 log storage that an individual flight will use. The
1121 available storage is divided into as many flights of the
1122 specified size as can fit in the available space. You can
1123 download and erase individual flight logs. If you fill up
1124 the available storage, future flights will not get logged
1125 until you erase some of the stored ones.
1128 Even though our flight computers (except TeleMini v1.0) can store
1129 multiple flights, we strongly recommend downloading and saving
1130 flight data after each flight.
1134 <title>Ignite Mode</title>
1136 Instead of firing one charge at apogee and another charge at
1137 a fixed height above the ground, you can configure the
1138 altimeter to fire both at apogee or both during
1139 descent. This was added to support an airframe Bdale designed that
1140 had two altimeters, one in the fin can and one in the nose.
1143 Providing the ability to use both igniters for apogee or
1144 main allows some level of redundancy without needing two
1145 flight computers. In Redundant Apogee or Redundant Main
1146 mode, the two charges will be fired two seconds apart.
1150 <title>Pad Orientation</title>
1152 TeleMetrum and TeleMega measure acceleration along the axis
1153 of the board. Which way the board is oriented affects the
1154 sign of the acceleration value. Instead of trying to guess
1155 which way the board is mounted in the air frame, the
1156 altimeter must be explicitly configured for either Antenna
1157 Up or Antenna Down. The default, Antenna Up, expects the end
1158 of the board connected to the 70cm antenna to be nearest the
1159 nose of the rocket, with the end containing the screw
1160 terminals nearest the tail.
1164 <title>Configurable Pyro Channels</title>
1166 In addition to the usual Apogee and Main pyro channels,
1167 TeleMega has four additional channels that can be configured
1168 to activate when various flight conditions are
1169 satisfied. You can select as many conditions as necessary;
1170 all of them must be met in order to activate the
1171 channel. The conditions available are:
1176 Acceleration away from the ground. Select a value, and
1177 then choose whether acceleration should be above or
1178 below that value. Acceleration is positive upwards, so
1179 accelerating towards the ground would produce negative
1180 numbers. Acceleration during descent is noisy and
1181 inaccurate, so be careful when using it during these
1182 phases of the flight.
1187 Vertical speed. Select a value, and then choose whether
1188 vertical speed should be above or below that
1189 value. Speed is positive upwards, so moving towards the
1190 ground would produce negative numbers. Speed during
1191 descent is a bit noisy and so be careful when using it
1192 during these phases of the flight.
1197 Height. Select a value, and then choose whether the
1198 height above the launch pad should be above or below
1204 Orientation. TeleMega contains a 3-axis gyroscope and
1205 accelerometer which is used to measure the current
1206 angle. Note that this angle is not the change in angle
1207 from the launch pad, but rather absolute relative to
1208 gravity; the 3-axis accelerometer is used to compute the
1209 angle of the rocket on the launch pad and initialize the
1210 system. Because this value is computed by integrating
1211 rate gyros, it gets progressively less accurate as the
1212 flight goes on. It should have an accumulated error of
1213 less than 0.2°/second (after 10 seconds of flight, the
1214 error should be less than 2°).
1217 The usual use of the orientation configuration is to
1218 ensure that the rocket is traveling mostly upwards when
1219 deciding whether to ignite air starts or additional
1220 stages. For that, choose a reasonable maximum angle
1221 (like 20°) and set the motor igniter to require an angle
1222 of less than that value.
1227 Flight Time. Time since boost was detected. Select a
1228 value and choose whether to activate the pyro channel
1229 before or after that amount of time.
1234 Ascending. A simple test saying whether the rocket is
1235 going up or not. This is exactly equivalent to testing
1236 whether the speed is > 0.
1241 Descending. A simple test saying whether the rocket is
1242 going down or not. This is exactly equivalent to testing
1243 whether the speed is < 0.
1248 After Motor. The flight software counts each time the
1249 rocket starts accelerating (presumably due to a motor or
1250 motors igniting). Use this value to count ignitions for
1251 multi-staged or multi-airstart launches.
1256 Delay. This value doesn't perform any checks, instead it
1257 inserts a delay between the time when the other
1258 parameters become true and when the pyro channel is
1264 Flight State. The flight software tracks the flight
1265 through a sequence of states:
1269 Boost. The motor has lit and the rocket is
1270 accelerating upwards.
1275 Fast. The motor has burned out and the rocket is
1276 descellerating, but it is going faster than 200m/s.
1281 Coast. The rocket is still moving upwards and
1282 decelerating, but the speed is less than 200m/s.
1287 Drogue. The rocket has reached apogee and is heading
1288 back down, but is above the configured Main
1294 Main. The rocket is still descending, and is below
1300 Landed. The rocket is no longer moving.
1306 You can select a state to limit when the pyro channel
1307 may activate; note that the check is based on when the
1308 rocket transitions <emphasis>into</emphasis> the state, and so checking for
1309 “greater than Boost” means that the rocket is currently
1310 in boost or some later state.
1313 When a motor burns out, the rocket enters either Fast or
1314 Coast state (depending on how fast it is moving). If the
1315 computer detects upwards acceleration again, it will
1316 move back to Boost state.
1326 <title>AltosUI</title>
1328 The AltosUI program provides a graphical user interface for
1329 interacting with the Altus Metrum product family. AltosUI can
1330 monitor telemetry data, configure devices and many other
1331 tasks. The primary interface window provides a selection of
1332 buttons, one for each major activity in the system. This chapter
1333 is split into sections, each of which documents one of the tasks
1334 provided from the top-level toolbar.
1337 <title>Monitor Flight</title>
1338 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
1340 Selecting this item brings up a dialog box listing all of the
1341 connected TeleDongle devices. When you choose one of these,
1342 AltosUI will create a window to display telemetry data as
1343 received by the selected TeleDongle device.
1346 All telemetry data received are automatically recorded in
1347 suitable log files. The name of the files includes the current
1348 date and rocket serial and flight numbers.
1351 The radio frequency being monitored by the TeleDongle device is
1352 displayed at the top of the window. You can configure the
1353 frequency by clicking on the frequency box and selecting the desired
1354 frequency. AltosUI remembers the last frequency selected for each
1355 TeleDongle and selects that automatically the next time you use
1359 Below the TeleDongle frequency selector, the window contains a few
1360 significant pieces of information about the altimeter providing
1361 the telemetry data stream:
1365 <para>The configured call-sign</para>
1368 <para>The device serial number</para>
1371 <para>The flight number. Each altimeter remembers how many
1377 The rocket flight state. Each flight passes through several
1378 states including Pad, Boost, Fast, Coast, Drogue, Main and
1384 The Received Signal Strength Indicator value. This lets
1385 you know how strong a signal TeleDongle is receiving. The
1386 radio inside TeleDongle operates down to about -99dBm;
1387 weaker signals may not be receivable. The packet link uses
1388 error detection and correction techniques which prevent
1389 incorrect data from being reported.
1394 The age of the displayed data, in seconds since the last
1395 successfully received telemetry packet. In normal operation
1396 this will stay in the low single digits. If the number starts
1397 counting up, then you are no longer receiving data over the radio
1398 link from the flight computer.
1403 Finally, the largest portion of the window contains a set of
1404 tabs, each of which contain some information about the rocket.
1405 They're arranged in 'flight order' so that as the flight
1406 progresses, the selected tab automatically switches to display
1407 data relevant to the current state of the flight. You can select
1408 other tabs at any time. The final 'table' tab displays all of
1409 the raw telemetry values in one place in a spreadsheet-like format.
1412 <title>Launch Pad</title>
1414 The 'Launch Pad' tab shows information used to decide when the
1415 rocket is ready for flight. The first elements include red/green
1416 indicators, if any of these is red, you'll want to evaluate
1417 whether the rocket is ready to launch:
1420 <term>Battery Voltage</term>
1423 This indicates whether the Li-Po battery powering the
1424 flight computer has sufficient charge to last for
1425 the duration of the flight. A value of more than
1426 3.8V is required for a 'GO' status.
1431 <term>Apogee Igniter Voltage</term>
1434 This indicates whether the apogee
1435 igniter has continuity. If the igniter has a low
1436 resistance, then the voltage measured here will be close
1437 to the Li-Po battery voltage. A value greater than 3.2V is
1438 required for a 'GO' status.
1443 <term>Main Igniter Voltage</term>
1446 This indicates whether the main
1447 igniter has continuity. If the igniter has a low
1448 resistance, then the voltage measured here will be close
1449 to the Li-Po battery voltage. A value greater than 3.2V is
1450 required for a 'GO' status.
1455 <term>On-board Data Logging</term>
1458 This indicates whether there is
1459 space remaining on-board to store flight data for the
1460 upcoming flight. If you've downloaded data, but failed
1461 to erase flights, there may not be any space
1462 left. Most of our flight computers can store multiple
1463 flights, depending on the configured maximum flight log
1464 size. TeleMini v1.0 stores only a single flight, so it
1466 downloaded and erased after each flight to capture
1467 data. This only affects on-board flight logging; the
1468 altimeter will still transmit telemetry and fire
1469 ejection charges at the proper times even if the flight
1470 data storage is full.
1475 <term>GPS Locked</term>
1478 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
1479 currently able to compute position information. GPS requires
1480 at least 4 satellites to compute an accurate position.
1485 <term>GPS Ready</term>
1488 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
1489 10 consecutive positions without losing lock. This ensures
1490 that the GPS receiver has reliable reception from the
1498 The Launchpad tab also shows the computed launch pad position
1499 and altitude, averaging many reported positions to improve the
1500 accuracy of the fix.
1504 <title>Ascent</title>
1506 This tab is shown during Boost, Fast and Coast
1507 phases. The information displayed here helps monitor the
1508 rocket as it heads towards apogee.
1511 The height, speed and acceleration are shown along with the
1512 maximum values for each of them. This allows you to quickly
1513 answer the most commonly asked questions you'll hear during
1517 The current latitude and longitude reported by the GPS are
1518 also shown. Note that under high acceleration, these values
1519 may not get updated as the GPS receiver loses position
1520 fix. Once the rocket starts coasting, the receiver should
1521 start reporting position again.
1524 Finally, the current igniter voltages are reported as in the
1525 Launch Pad tab. This can help diagnose deployment failures
1526 caused by wiring which comes loose under high acceleration.
1530 <title>Descent</title>
1532 Once the rocket has reached apogee and (we hope) activated the
1533 apogee charge, attention switches to tracking the rocket on
1534 the way back to the ground, and for dual-deploy flights,
1535 waiting for the main charge to fire.
1538 To monitor whether the apogee charge operated correctly, the
1539 current descent rate is reported along with the current
1540 height. Good descent rates vary based on the choice of recovery
1541 components, but generally range from 15-30m/s on drogue and should
1542 be below 10m/s when under the main parachute in a dual-deploy flight.
1545 With GPS-equipped flight computers, you can locate the rocket in the
1546 sky using the elevation and bearing information to figure
1547 out where to look. Elevation is in degrees above the
1548 horizon. Bearing is reported in degrees relative to true
1549 north. Range can help figure out how big the rocket will
1550 appear. Ground Distance shows how far it is to a point
1551 directly under the rocket and can help figure out where the
1552 rocket is likely to land. Note that all of these values are
1553 relative to the pad location. If the elevation is near 90°,
1554 the rocket is over the pad, not over you.
1557 Finally, the igniter voltages are reported in this tab as
1558 well, both to monitor the main charge as well as to see what
1559 the status of the apogee charge is. Note that some commercial
1560 e-matches are designed to retain continuity even after being
1561 fired, and will continue to show as green or return from red to
1566 <title>Landed</title>
1568 Once the rocket is on the ground, attention switches to
1569 recovery. While the radio signal is often lost once the
1570 rocket is on the ground, the last reported GPS position is
1571 generally within a short distance of the actual landing location.
1574 The last reported GPS position is reported both by
1575 latitude and longitude as well as a bearing and distance from
1576 the launch pad. The distance should give you a good idea of
1577 whether to walk or hitch a ride. Take the reported
1578 latitude and longitude and enter them into your hand-held GPS
1579 unit and have that compute a track to the landing location.
1582 Our flight computers will continue to transmit RDF
1583 tones after landing, allowing you to locate the rocket by
1584 following the radio signal if necessary. You may need to get
1585 away from the clutter of the flight line, or even get up on
1586 a hill (or your neighbor's RV roof) to receive the RDF signal.
1589 The maximum height, speed and acceleration reported
1590 during the flight are displayed for your admiring observers.
1591 The accuracy of these immediate values depends on the quality
1592 of your radio link and how many packets were received.
1593 Recovering the on-board data after flight may yield
1594 more precise results.
1597 To get more detailed information about the flight, you can
1598 click on the 'Graph Flight' button which will bring up a
1599 graph window for the current flight.
1603 <title>Site Map</title>
1605 When the TeleMetrum has a GPS fix, the Site Map tab will map
1606 the rocket's position to make it easier for you to locate the
1607 rocket, both while it is in the air, and when it has landed. The
1608 rocket's state is indicated by color: white for pad, red for
1609 boost, pink for fast, yellow for coast, light blue for drogue,
1610 dark blue for main, and black for landed.
1613 The map's scale is approximately 3m (10ft) per pixel. The map
1614 can be dragged using the left mouse button. The map will attempt
1615 to keep the rocket roughly centered while data is being received.
1618 Images are fetched automatically via the Google Maps Static API,
1619 and cached on disk for reuse. If map images cannot be downloaded,
1620 the rocket's path will be traced on a dark gray background
1624 You can pre-load images for your favorite launch sites
1625 before you leave home; check out the 'Preload Maps' section below.
1630 <title>Save Flight Data</title>
1632 The altimeter records flight data to its internal flash memory.
1633 TeleMetrum data is recorded at a much higher rate than the telemetry
1634 system can handle, and is not subject to radio drop-outs. As
1635 such, it provides a more complete and precise record of the
1636 flight. The 'Save Flight Data' button allows you to read the
1637 flash memory and write it to disk.
1640 Clicking on the 'Save Flight Data' button brings up a list of
1641 connected flight computers and TeleDongle devices. If you select a
1642 flight computer, the flight data will be downloaded from that
1643 device directly. If you select a TeleDongle device, flight data
1644 will be downloaded from a flight computer over radio link via the
1645 specified TeleDongle. See the chapter on Controlling An Altimeter
1646 Over The Radio Link for more information.
1649 After the device has been selected, a dialog showing the
1650 flight data saved in the device will be shown allowing you to
1651 select which flights to download and which to delete. With
1652 version 0.9 or newer firmware, you must erase flights in order
1653 for the space they consume to be reused by another
1654 flight. This prevents accidentally losing flight data
1655 if you neglect to download data before flying again. Note that
1656 if there is no more space available in the device, then no
1657 data will be recorded during the next flight.
1660 The file name for each flight log is computed automatically
1661 from the recorded flight date, altimeter serial number and
1662 flight number information.
1666 <title>Replay Flight</title>
1668 Select this button and you are prompted to select a flight
1669 record file, either a .telem file recording telemetry data or a
1670 .eeprom file containing flight data saved from the altimeter
1674 Once a flight record is selected, the flight monitor interface
1675 is displayed and the flight is re-enacted in real time. Check
1676 the Monitor Flight chapter above to learn how this window operates.
1680 <title>Graph Data</title>
1682 Select this button and you are prompted to select a flight
1683 record file, either a .telem file recording telemetry data or a
1684 .eeprom file containing flight data saved from
1688 Once a flight record is selected, a window with multiple tabs is
1692 <term>Flight Graph</term>
1695 By default, the graph contains acceleration (blue),
1696 velocity (green) and altitude (red).
1701 <term>Configure Graph</term>
1704 This selects which graph elements to show, and, at the
1705 very bottom, lets you switch between metric and
1711 <term>Flight Statistics</term>
1714 Shows overall data computed from the flight.
1722 Shows a satellite image of the flight area overlaid
1723 with the path of the flight. The red concentric
1724 circles mark the launch pad, the black concentric
1725 circles mark the landing location.
1732 The graph can be zoomed into a particular area by clicking and
1733 dragging down and to the right. Once zoomed, the graph can be
1734 reset by clicking and dragging up and to the left. Holding down
1735 control and clicking and dragging allows the graph to be panned.
1736 The right mouse button causes a pop-up menu to be displayed, giving
1737 you the option save or print the plot.
1740 Note that telemetry files will generally produce poor graphs
1741 due to the lower sampling rate and missed telemetry packets.
1742 Use saved flight data in .eeprom files for graphing where possible.
1746 <title>Export Data</title>
1748 This tool takes the raw data files and makes them available for
1749 external analysis. When you select this button, you are prompted to
1750 select a flight data file, which can be either a .eeprom or .telem.
1751 The .eeprom files contain higher resolution and more continuous data,
1752 while .telem files contain receiver signal strength information.
1753 Next, a second dialog appears which is used to select
1754 where to write the resulting file. It has a selector to choose
1755 between CSV and KML file formats.
1758 <title>Comma Separated Value Format</title>
1760 This is a text file containing the data in a form suitable for
1761 import into a spreadsheet or other external data analysis
1762 tool. The first few lines of the file contain the version and
1763 configuration information from the altimeter, then
1764 there is a single header line which labels all of the
1765 fields. All of these lines start with a '#' character which
1766 many tools can be configured to skip over.
1769 The remaining lines of the file contain the data, with each
1770 field separated by a comma and at least one space. All of
1771 the sensor values are converted to standard units, with the
1772 barometric data reported in both pressure, altitude and
1773 height above pad units.
1777 <title>Keyhole Markup Language (for Google Earth)</title>
1779 This is the format used by Google Earth to provide an overlay
1780 within that application. With this, you can use Google Earth to
1781 see the whole flight path in 3D.
1786 <title>Configure Altimeter</title>
1788 Select this button and then select either an altimeter or
1789 TeleDongle Device from the list provided. Selecting a TeleDongle
1790 device will use the radio link to configure a remote altimeter.
1793 The first few lines of the dialog provide information about the
1794 connected device, including the product name,
1795 software version and hardware serial number. Below that are the
1796 individual configuration entries.
1799 At the bottom of the dialog, there are four buttons:
1804 Save. This writes any changes to the
1805 configuration parameter block in flash memory. If you don't
1806 press this button, any changes you make will be lost.
1811 Reset. This resets the dialog to the most recently saved values,
1812 erasing any changes you have made.
1817 Reboot. This reboots the device. Use this to
1818 switch from idle to pad mode by rebooting once the rocket is
1819 oriented for flight, or to confirm changes you think you saved
1825 Close. This closes the dialog. Any unsaved changes will be
1831 The rest of the dialog contains the parameters to be configured.
1834 <title>Main Deploy Altitude</title>
1836 This sets the altitude (above the recorded pad altitude) at
1837 which the 'main' igniter will fire. The drop-down menu shows
1838 some common values, but you can edit the text directly and
1839 choose whatever you like. If the apogee charge fires below
1840 this altitude, then the main charge will fire two seconds
1841 after the apogee charge fires.
1845 <title>Apogee Delay</title>
1847 When flying redundant electronics, it's often important to
1848 ensure that multiple apogee charges don't fire at precisely
1849 the same time, as that can over pressurize the apogee deployment
1850 bay and cause a structural failure of the air-frame. The Apogee
1851 Delay parameter tells the flight computer to fire the apogee
1852 charge a certain number of seconds after apogee has been
1857 <title>Radio Frequency</title>
1859 This configures which of the frequencies to use for both
1860 telemetry and packet command mode. Note that if you set this
1861 value via packet command mode, the TeleDongle frequency will
1862 also be automatically reconfigured to match so that
1863 communication will continue afterwards.
1867 <title>RF Calibration</title>
1869 The radios in every Altus Metrum device are calibrated at the
1870 factory to ensure that they transmit and receive on the
1871 specified frequency. If you need to you can adjust the calibration
1872 by changing this value. Do not do this without understanding what
1873 the value means, read the appendix on calibration and/or the source
1874 code for more information. To change a TeleDongle's calibration,
1875 you must reprogram the unit completely.
1879 <title>Telemetry/RDF/APRS Enable</title>
1881 Enables the radio for transmission during flight. When
1882 disabled, the radio will not transmit anything during flight
1887 <title>APRS Interval</title>
1889 How often to transmit GPS information via APRS. This option
1890 is available on TeleMetrum v2 and TeleMega
1891 boards. TeleMetrum v1 boards cannot transmit APRS
1892 packets. Note that a single APRS packet takes nearly a full
1893 second to transmit, so enabling this option will prevent
1894 sending any other telemetry during that time.
1898 <title>Callsign</title>
1900 This sets the call sign included in each telemetry packet. Set this
1901 as needed to conform to your local radio regulations.
1905 <title>Maximum Flight Log Size</title>
1907 This sets the space (in kilobytes) allocated for each flight
1908 log. The available space will be divided into chunks of this
1909 size. A smaller value will allow more flights to be stored,
1910 a larger value will record data from longer flights.
1914 <title>Ignite Mode</title>
1916 TeleMetrum and TeleMini provide two igniter channels as they
1917 were originally designed as dual-deploy flight
1918 computers. This configuration parameter allows the two
1919 channels to be used in different configurations.
1924 Dual Deploy. This is the usual mode of operation; the
1925 'apogee' channel is fired at apogee and the 'main'
1926 channel at the height above ground specified by the
1927 'Main Deploy Altitude' during descent.
1932 Redundant Apogee. This fires both channels at
1933 apogee, the 'apogee' channel first followed after a two second
1934 delay by the 'main' channel.
1939 Redundant Main. This fires both channels at the
1940 height above ground specified by the Main Deploy
1941 Altitude setting during descent. The 'apogee'
1942 channel is fired first, followed after a two second
1943 delay by the 'main' channel.
1949 <title>Pad Orientation</title>
1951 Because they include accelerometers, TeleMetrum and
1952 TeleMega are sensitive to the orientation of the board. By
1953 default, they expect the antenna end to point forward. This
1954 parameter allows that default to be changed, permitting the
1955 board to be mounted with the antenna pointing aft instead.
1960 Antenna Up. In this mode, the antenna end of the
1961 flight computer must point forward, in line with the
1962 expected flight path.
1967 Antenna Down. In this mode, the antenna end of the
1968 flight computer must point aft, in line with the
1969 expected flight path.
1975 <title>Configure Pyro Channels</title>
1977 This opens a separate window to configure the additional
1978 pyro channels available on TeleMega. One column is
1979 presented for each channel. Each row represents a single
1980 parameter, if enabled the parameter must meet the specified
1981 test for the pyro channel to be fired. See the Pyro Channels
1982 section in the System Operation chapter above for a
1983 description of these parameters.
1986 Select conditions and set the related value; the pyro
1987 channel will be activated when <emphasis>all</emphasis> of the
1988 conditions are met. Each pyro channel has a separate set of
1989 configuration values, so you can use different values for
1990 the same condition with different channels.
1993 Once you have selected the appropriate configuration for all
1994 of the necessary pyro channels, you can save the pyro
1995 configuration along with the rest of the flight computer
1996 configuration by pressing the 'Save' button in the main
1997 Configure Flight Computer window.
2002 <title>Configure AltosUI</title>
2004 This button presents a dialog so that you can configure the AltosUI global settings.
2007 <title>Voice Settings</title>
2009 AltosUI provides voice announcements during flight so that you
2010 can keep your eyes on the sky and still get information about
2011 the current flight status. However, sometimes you don't want
2016 <para>Enable—turns all voice announcements on and off</para>
2020 Test Voice—Plays a short message allowing you to verify
2021 that the audio system is working and the volume settings
2028 <title>Log Directory</title>
2030 AltosUI logs all telemetry data and saves all TeleMetrum flash
2031 data to this directory. This directory is also used as the
2032 staring point when selecting data files for display or export.
2035 Click on the directory name to bring up a directory choosing
2036 dialog, select a new directory and click 'Select Directory' to
2037 change where AltosUI reads and writes data files.
2041 <title>Callsign</title>
2043 This value is transmitted in each command packet sent from
2044 TeleDongle and received from an altimeter. It is not used in
2045 telemetry mode, as the callsign configured in the altimeter board
2046 is included in all telemetry packets. Configure this
2047 with the AltosUI operators call sign as needed to comply with
2048 your local radio regulations.
2051 Note that to successfully command a flight computer over the radio
2052 (to configure the altimeter, monitor idle, or fire pyro charges),
2053 the callsign configured here must exactly match the callsign
2054 configured in the flight computer. This matching is case
2059 <title>Imperial Units</title>
2061 This switches between metric units (meters) and imperial
2062 units (feet and miles). This affects the display of values
2063 use during flight monitoring, configuration, data graphing
2064 and all of the voice announcements. It does not change the
2065 units used when exporting to CSV files, those are always
2066 produced in metric units.
2070 <title>Font Size</title>
2072 Selects the set of fonts used in the flight monitor
2073 window. Choose between the small, medium and large sets.
2077 <title>Serial Debug</title>
2079 This causes all communication with a connected device to be
2080 dumped to the console from which AltosUI was started. If
2081 you've started it from an icon or menu entry, the output
2082 will simply be discarded. This mode can be useful to debug
2083 various serial communication issues.
2087 <title>Manage Frequencies</title>
2089 This brings up a dialog where you can configure the set of
2090 frequencies shown in the various frequency menus. You can
2091 add as many as you like, or even reconfigure the default
2092 set. Changing this list does not affect the frequency
2093 settings of any devices, it only changes the set of
2094 frequencies shown in the menus.
2099 <title>Configure Groundstation</title>
2101 Select this button and then select a TeleDongle Device from the list provided.
2104 The first few lines of the dialog provide information about the
2105 connected device, including the product name,
2106 software version and hardware serial number. Below that are the
2107 individual configuration entries.
2110 Note that the TeleDongle itself doesn't save any configuration
2111 data, the settings here are recorded on the local machine in
2112 the Java preferences database. Moving the TeleDongle to
2113 another machine, or using a different user account on the same
2114 machine will cause settings made here to have no effect.
2117 At the bottom of the dialog, there are three buttons:
2122 Save. This writes any changes to the
2123 local Java preferences file. If you don't
2124 press this button, any changes you make will be lost.
2129 Reset. This resets the dialog to the most recently saved values,
2130 erasing any changes you have made.
2135 Close. This closes the dialog. Any unsaved changes will be
2141 The rest of the dialog contains the parameters to be configured.
2144 <title>Frequency</title>
2146 This configures the frequency to use for both telemetry and
2147 packet command mode. Set this before starting any operation
2148 involving packet command mode so that it will use the right
2149 frequency. Telemetry monitoring mode also provides a menu to
2150 change the frequency, and that menu also sets the same Java
2151 preference value used here.
2155 <title>Radio Calibration</title>
2157 The radios in every Altus Metrum device are calibrated at the
2158 factory to ensure that they transmit and receive on the
2159 specified frequency. To change a TeleDongle's calibration,
2160 you must reprogram the unit completely, so this entry simply
2161 shows the current value and doesn't allow any changes.
2166 <title>Flash Image</title>
2168 This reprograms Altus Metrum devices with new
2169 firmware. TeleMetrum v1.x, TeleDongle, TeleMini and TeleBT are
2170 all reprogrammed by using another similar unit as a
2171 programming dongle (pair programming). TeleMega, TeleMetrum v2
2172 and EasyMini are all programmed directly over their USB ports
2173 (self programming). Please read the directions for flashing
2174 devices in the Updating Device Firmware chapter below.
2177 For “self programming”, connect USB to the device to be
2178 programmed and push the 'Flash Image' button. That will
2179 present a dialog box listing all of the connected
2180 devices. Carefully select the device to be programmed.
2183 For “pair programming”, once you have the programmer and
2184 target devices connected, push the 'Flash Image' button. That
2185 will present a dialog box listing all of the connected
2186 devices. Carefully select the programmer device, not the
2187 device to be programmed.
2190 Next, select the image to flash to the device. These are named
2191 with the product name and firmware version. The file selector
2192 will start in the directory containing the firmware included
2193 with the AltosUI package. Navigate to the directory containing
2194 the desired firmware if it isn't there.
2197 Next, a small dialog containing the device serial number and
2198 RF calibration values should appear. If these values are
2199 incorrect (possibly due to a corrupted image in the device),
2200 enter the correct values here.
2203 Finally, a dialog containing a progress bar will follow the
2204 programming process.
2207 When programming is complete, the target device will
2208 reboot. Note that if a pair programmed target device is
2209 connected via USB, you will have to unplug it and then plug it
2210 back in for the USB connection to reset so that you can
2211 communicate with the device again.
2215 <title>Fire Igniter</title>
2217 This activates the igniter circuits in the flight computer to help
2218 test recovery systems deployment. Because this command can operate
2219 over the Packet Command Link, you can prepare the rocket as
2220 for flight and then test the recovery system without needing
2221 to snake wires inside the air-frame.
2224 Selecting the 'Fire Igniter' button brings up the usual device
2225 selection dialog. Pick the desired device. This brings up another
2226 window which shows the current continuity test status for both
2227 apogee and main charges.
2230 Next, select the desired igniter to fire. This will enable the
2234 Select the 'Arm' button. This enables the 'Fire' button. The
2235 word 'Arm' is replaced by a countdown timer indicating that
2236 you have 10 seconds to press the 'Fire' button or the system
2237 will deactivate, at which point you start over again at
2238 selecting the desired igniter.
2242 <title>Scan Channels</title>
2244 This listens for telemetry packets on all of the configured
2245 frequencies, displaying information about each device it
2246 receives a packet from. You can select which of the three
2247 telemetry formats should be tried; by default, it only listens
2248 for the standard telemetry packets used in v1.0 and later
2253 <title>Load Maps</title>
2255 Before heading out to a new launch site, you can use this to
2256 load satellite images in case you don't have internet
2257 connectivity at the site. This loads a fairly large area
2258 around the launch site, which should cover any flight you're likely to make.
2261 There's a drop-down menu of launch sites we know about; if
2262 your favorites aren't there, please let us know the lat/lon
2263 and name of the site. The contents of this list are actually
2264 downloaded from our server at run-time, so as new sites are sent
2265 in, they'll get automatically added to this list.
2268 If the launch site isn't in the list, you can manually enter the lat/lon values
2271 Clicking the 'Load Map' button will fetch images from Google
2272 Maps; note that Google limits how many images you can fetch at
2273 once, so if you load more than one launch site, you may get
2274 some gray areas in the map which indicate that Google is tired
2275 of sending data to you. Try again later.
2279 <title>Monitor Idle</title>
2281 This brings up a dialog similar to the Monitor Flight UI,
2282 except it works with the altimeter in “idle” mode by sending
2283 query commands to discover the current state rather than
2284 listening for telemetry packets. Because this uses command
2285 mode, it needs to have the TeleDongle and flight computer
2286 callsigns match exactly. If you can receive telemetry, but
2287 cannot manage to run Monitor Idle, then it's very likely that
2288 your callsigns are different in some way.
2293 <title>AltosDroid</title>
2295 AltosDroid provides the same flight monitoring capabilities as
2296 AltosUI, but runs on Android devices and is designed to connect
2297 to a TeleBT receiver over Bluetooth™. AltosDroid monitors
2298 telemetry data, logging it to internal storage in the Android
2299 device, and presents that data in a UI the same way the 'Monitor
2300 Flight' window does in AltosUI.
2303 This manual will explain how to configure AltosDroid, connect
2304 to TeleBT, operate the flight monitoring interface and describe
2305 what the displayed data means.
2308 <title>Installing AltosDroid</title>
2310 AltosDroid is included in the Google Play store. To install
2311 it on your Android device, open open the Google Play Store
2312 application and search for “altosdroid”. Make sure you don't
2313 have a space between “altos” and “droid” or you probably won't
2314 find what you want. That should bring you to the right page
2315 from which you can download and install the application.
2319 <title>Connecting to TeleBT</title>
2321 Press the Android 'Menu' button or soft-key to see the
2322 configuration options available. Select the 'Connect a device'
2323 option and then the 'Scan for devices' entry at the bottom to
2324 look for your TeleBT device. Select your device, and when it
2325 asks for the code, enter '1234'.
2328 Subsequent connections will not require you to enter that
2329 code, and your 'paired' device will appear in the list without
2334 <title>Configuring AltosDroid</title>
2336 The only configuration option available for AltosDroid is
2337 which frequency to listen on. Press the Android 'Menu' button
2338 or soft-key and pick the 'Select radio frequency' entry. That
2339 brings up a menu of pre-set radio frequencies; pick the one
2340 which matches your altimeter.
2344 <title>AltosDroid Flight Monitoring</title>
2346 AltosDroid is designed to mimic the AltosUI flight monitoring
2347 display, providing separate tabs for each stage of your rocket
2348 flight along with a tab containing a map of the local area
2349 with icons marking the current location of the altimeter and
2355 The 'Launch Pad' tab shows information used to decide when the
2356 rocket is ready for flight. The first elements include red/green
2357 indicators, if any of these is red, you'll want to evaluate
2358 whether the rocket is ready to launch:
2361 <term>Battery Voltage</term>
2364 This indicates whether the Li-Po battery
2365 powering the TeleMetrum has sufficient charge to last for
2366 the duration of the flight. A value of more than
2367 3.8V is required for a 'GO' status.
2372 <term>Apogee Igniter Voltage</term>
2375 This indicates whether the apogee
2376 igniter has continuity. If the igniter has a low
2377 resistance, then the voltage measured here will be close
2378 to the Li-Po battery voltage. A value greater than 3.2V is
2379 required for a 'GO' status.
2384 <term>Main Igniter Voltage</term>
2387 This indicates whether the main
2388 igniter has continuity. If the igniter has a low
2389 resistance, then the voltage measured here will be close
2390 to the Li-Po battery voltage. A value greater than 3.2V is
2391 required for a 'GO' status.
2396 <term>On-board Data Logging</term>
2399 This indicates whether there is
2400 space remaining on-board to store flight data for the
2401 upcoming flight. If you've downloaded data, but failed
2402 to erase flights, there may not be any space
2403 left. TeleMetrum can store multiple flights, depending
2404 on the configured maximum flight log size. TeleMini
2405 stores only a single flight, so it will need to be
2406 downloaded and erased after each flight to capture
2407 data. This only affects on-board flight logging; the
2408 altimeter will still transmit telemetry and fire
2409 ejection charges at the proper times.
2414 <term>GPS Locked</term>
2417 For a TeleMetrum or TeleMega device, this indicates whether the GPS receiver is
2418 currently able to compute position information. GPS requires
2419 at least 4 satellites to compute an accurate position.
2424 <term>GPS Ready</term>
2427 For a TeleMetrum or TeleMega device, this indicates whether GPS has reported at least
2428 10 consecutive positions without losing lock. This ensures
2429 that the GPS receiver has reliable reception from the
2437 The Launchpad tab also shows the computed launch pad position
2438 and altitude, averaging many reported positions to improve the
2439 accuracy of the fix.
2444 <title>Downloading Flight Logs</title>
2446 AltosDroid always saves every bit of telemetry data it
2447 receives. To download that to a computer for use with AltosUI,
2448 simply remove the SD card from your Android device, or connect
2449 your device to your computer's USB port and browse the files
2450 on that device. You will find '.telem' files in the TeleMetrum
2451 directory that will work with AltosUI directly.
2456 <title>Using Altus Metrum Products</title>
2458 <title>Being Legal</title>
2460 First off, in the US, you need an <ulink url="http://www.altusmetrum.org/Radio/">amateur radio license</ulink> or
2461 other authorization to legally operate the radio transmitters that are part
2466 <title>In the Rocket</title>
2468 In the rocket itself, you just need a <ulink url="http://www.altusmetrum.org/TeleMetrum/">TeleMetrum</ulink> or
2469 <ulink url="http://www.altusmetrum.org/TeleMini/">TeleMini</ulink> board and
2470 a single-cell, 3.7 volt nominal Li-Po rechargeable battery. An
2471 850mAh battery weighs less than a 9V alkaline battery, and will
2472 run a TeleMetrum for hours.
2473 A 110mAh battery weighs less than a triple A battery and will run a TeleMetrum for
2474 a few hours, or a TeleMini for much (much) longer.
2477 By default, we ship the altimeters with a simple wire antenna. If your
2478 electronics bay or the air-frame it resides within is made of carbon fiber,
2479 which is opaque to RF signals, you may choose to have an SMA connector
2480 installed so that you can run a coaxial cable to an antenna mounted
2481 elsewhere in the rocket.
2485 <title>On the Ground</title>
2487 To receive the data stream from the rocket, you need an antenna and short
2488 feed-line connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. If possible, use an SMA to BNC
2489 adapter instead of feedline between the antenna feedpoint and
2490 TeleDongle, as this will give you the best performance. The
2491 TeleDongle in turn plugs directly into the USB port on a notebook
2492 computer. Because TeleDongle looks like a simple serial port, your computer
2493 does not require special device drivers... just plug it in.
2496 The GUI tool, AltosUI, is written in Java and runs across
2497 Linux, Mac OS and Windows. There's also a suite of C tools
2498 for Linux which can perform most of the same tasks.
2501 After the flight, you can use the radio link to extract the more detailed data
2502 logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
2503 TeleMetrum board directly. Pulling out the data without having to open up
2504 the rocket is pretty cool! A USB cable is also how you charge the Li-Po
2505 battery, so you'll want one of those anyway... the same cable used by lots
2506 of digital cameras and other modern electronic stuff will work fine.
2509 If your TeleMetrum-equipped rocket lands out of sight, you may enjoy having a hand-held GPS
2510 receiver, so that you can put in a way-point for the last reported rocket
2511 position before touch-down. This makes looking for your rocket a lot like
2512 Geo-Caching... just go to the way-point and look around starting from there.
2515 You may also enjoy having a ham radio “HT” that covers the 70cm band... you
2516 can use that with your antenna to direction-find the rocket on the ground
2517 the same way you can use a Walston or Beeline tracker. This can be handy
2518 if the rocket is hiding in sage brush or a tree, or if the last GPS position
2519 doesn't get you close enough because the rocket dropped into a canyon, or
2520 the wind is blowing it across a dry lake bed, or something like that... Keith
2521 currently uses a Yaesu VX-7R, Bdale has a Baofung UV-5R
2522 which isn't as nice, but was a whole lot cheaper.
2525 So, to recap, on the ground the hardware you'll need includes:
2526 <orderedlist inheritnum='inherit' numeration='arabic'>
2529 an antenna and feed-line or adapter
2544 optionally, a hand-held GPS receiver
2549 optionally, an HT or receiver covering 435 MHz
2555 The best hand-held commercial directional antennas we've found for radio
2556 direction finding rockets are from
2557 <ulink url="http://www.arrowantennas.com/" >
2560 The 440-3 and 440-5 are both good choices for finding a
2561 TeleMetrum- or TeleMini- equipped rocket when used with a suitable
2562 70cm HT. TeleDongle and an SMA to BNC adapter fit perfectly
2563 between the driven element and reflector of Arrow antennas.
2567 <title>Data Analysis</title>
2569 Our software makes it easy to log the data from each flight, both the
2570 telemetry received during the flight itself, and the more
2571 complete data log recorded in the flash memory on the altimeter
2572 board. Once this data is on your computer, our post-flight tools make it
2573 easy to quickly get to the numbers everyone wants, like apogee altitude,
2574 max acceleration, and max velocity. You can also generate and view a
2575 standard set of plots showing the altitude, acceleration, and
2576 velocity of the rocket during flight. And you can even export a TeleMetrum data file
2577 usable with Google Maps and Google Earth for visualizing the flight path
2578 in two or three dimensions!
2581 Our ultimate goal is to emit a set of files for each flight that can be
2582 published as a web page per flight, or just viewed on your local disk with
2587 <title>Future Plans</title>
2589 In the future, we intend to offer “companion boards” for the rocket
2590 that will plug in to TeleMetrum to collect additional data, provide
2591 more pyro channels, and so forth.
2594 Also under design is a new flight computer with more sensors, more
2595 pyro channels, and a more powerful radio system designed for use
2596 in multi-stage, complex, and extreme altitude projects.
2599 We are also working on alternatives to TeleDongle. One is a
2600 a stand-alone, hand-held ground terminal that will allow monitoring
2601 the rocket's status, collecting data during flight, and logging data
2602 after flight without the need for a notebook computer on the
2603 flight line. Particularly since it is so difficult to read most
2604 notebook screens in direct sunlight, we think this will be a great
2605 thing to have. We are also working on a TeleDongle variant with
2606 Bluetooth™ that will work with Android phones and tablets.
2609 Because all of our work is open, both the hardware designs and the
2610 software, if you have some great idea for an addition to the current
2611 Altus Metrum family, feel free to dive in and help! Or let us know
2612 what you'd like to see that we aren't already working on, and maybe
2613 we'll get excited about it too...
2617 <ulink url="http://altusmetrum.org/">web site</ulink> for more news
2618 and information as our family of products evolves!
2623 <title>Altimeter Installation Recommendations</title>
2625 Building high-power rockets that fly safely is hard enough. Mix
2626 in some sophisticated electronics and a bunch of radio energy
2627 and oftentimes you find few perfect solutions. This chapter
2628 contains some suggestions about how to install Altus Metrum
2629 products into the rocket air-frame, including how to safely and
2630 reliably mix a variety of electronics into the same air-frame.
2633 <title>Mounting the Altimeter</title>
2635 The first consideration is to ensure that the altimeter is
2636 securely fastened to the air-frame. For TeleMetrum, we use
2637 nylon standoffs and nylon screws; they're good to at least 50G
2638 and cannot cause any electrical issues on the board. For
2639 TeleMini, we usually cut small pieces of 1/16 inch balsa to fit
2640 under the screw holes, and then take 2x56 nylon screws and
2641 screw them through the TeleMini mounting holes, through the
2642 balsa and into the underlying material.
2644 <orderedlist inheritnum='inherit' numeration='arabic'>
2647 Make sure TeleMetrum is aligned precisely along the axis of
2648 acceleration so that the accelerometer can accurately
2649 capture data during the flight.
2654 Watch for any metal touching components on the
2655 board. Shorting out connections on the bottom of the board
2656 can cause the altimeter to fail during flight.
2662 <title>Dealing with the Antenna</title>
2664 The antenna supplied is just a piece of solid, insulated,
2665 wire. If it gets damaged or broken, it can be easily
2666 replaced. It should be kept straight and not cut; bending or
2667 cutting it will change the resonant frequency and/or
2668 impedance, making it a less efficient radiator and thus
2669 reducing the range of the telemetry signal.
2672 Keeping metal away from the antenna will provide better range
2673 and a more even radiation pattern. In most rockets, it's not
2674 entirely possible to isolate the antenna from metal
2675 components; there are often bolts, all-thread and wires from other
2676 electronics to contend with. Just be aware that the more stuff
2677 like this around the antenna, the lower the range.
2680 Make sure the antenna is not inside a tube made or covered
2681 with conducting material. Carbon fiber is the most common
2682 culprit here -- CF is a good conductor and will effectively
2683 shield the antenna, dramatically reducing signal strength and
2684 range. Metallic flake paint is another effective shielding
2685 material which is to be avoided around any antennas.
2688 If the ebay is large enough, it can be convenient to simply
2689 mount the altimeter at one end and stretch the antenna out
2690 inside. Taping the antenna to the sled can keep it straight
2691 under acceleration. If there are metal rods, keep the
2692 antenna as far away as possible.
2695 For a shorter ebay, it's quite practical to have the antenna
2696 run through a bulkhead and into an adjacent bay. Drill a small
2697 hole in the bulkhead, pass the antenna wire through it and
2698 then seal it up with glue or clay. We've also used acrylic
2699 tubing to create a cavity for the antenna wire. This works a
2700 bit better in that the antenna is known to stay straight and
2701 not get folded by recovery components in the bay. Angle the
2702 tubing towards the side wall of the rocket and it ends up
2703 consuming very little space.
2706 If you need to place the antenna at a distance from the
2707 altimeter, you can replace the antenna with an edge-mounted
2708 SMA connector, and then run 50Ω coax from the board to the
2709 antenna. Building a remote antenna is beyond the scope of this
2714 <title>Preserving GPS Reception</title>
2716 The GPS antenna and receiver in TeleMetrum are highly
2717 sensitive and normally have no trouble tracking enough
2718 satellites to provide accurate position information for
2719 recovering the rocket. However, there are many ways to
2720 attenuate the GPS signal.
2721 <orderedlist inheritnum='inherit' numeration='arabic'>
2724 Conductive tubing or coatings. Carbon fiber and metal
2725 tubing, or metallic paint will all dramatically attenuate the
2726 GPS signal. We've never heard of anyone successfully
2727 receiving GPS from inside these materials.
2732 Metal components near the GPS patch antenna. These will
2733 de-tune the patch antenna, changing the resonant frequency
2734 away from the L1 carrier and reduce the effectiveness of the
2735 antenna. You can place as much stuff as you like beneath the
2736 antenna as that's covered with a ground plane. But, keep
2737 wires and metal out from above the patch antenna.
2744 <title>Radio Frequency Interference</title>
2746 Any altimeter will generate RFI; the digital circuits use
2747 high-frequency clocks that spray radio interference across a
2748 wide band. Altus Metrum altimeters generate intentional radio
2749 signals as well, increasing the amount of RF energy around the board.
2752 Rocketry altimeters also use precise sensors measuring air
2753 pressure and acceleration. Tiny changes in voltage can cause
2754 these sensor readings to vary by a huge amount. When the
2755 sensors start mis-reporting data, the altimeter can either
2756 fire the igniters at the wrong time, or not fire them at all.
2759 Voltages are induced when radio frequency energy is
2760 transmitted from one circuit to another. Here are things that
2761 influence the induced voltage and current:
2766 Keep wires from different circuits apart. Moving circuits
2767 further apart will reduce RFI.
2772 Avoid parallel wires from different circuits. The longer two
2773 wires run parallel to one another, the larger the amount of
2774 transferred energy. Cross wires at right angles to reduce
2780 Twist wires from the same circuits. Two wires the same
2781 distance from the transmitter will get the same amount of
2782 induced energy which will then cancel out. Any time you have
2783 a wire pair running together, twist the pair together to
2784 even out distances and reduce RFI. For altimeters, this
2785 includes battery leads, switch hookups and igniter
2791 Avoid resonant lengths. Know what frequencies are present
2792 in the environment and avoid having wire lengths near a
2793 natural resonant length. Altusmetrum products transmit on the
2794 70cm amateur band, so you should avoid lengths that are a
2795 simple ratio of that length; essentially any multiple of ¼
2796 of the wavelength (17.5cm).
2802 <title>The Barometric Sensor</title>
2804 Altusmetrum altimeters measure altitude with a barometric
2805 sensor, essentially measuring the amount of air above the
2806 rocket to figure out how high it is. A large number of
2807 measurements are taken as the altimeter initializes itself to
2808 figure out the pad altitude. Subsequent measurements are then
2809 used to compute the height above the pad.
2812 To accurately measure atmospheric pressure, the ebay
2813 containing the altimeter must be vented outside the
2814 air-frame. The vent must be placed in a region of linear
2815 airflow, have smooth edges, and away from areas of increasing or
2816 decreasing pressure.
2819 The barometric sensor in the altimeter is quite sensitive to
2820 chemical damage from the products of APCP or BP combustion, so
2821 make sure the ebay is carefully sealed from any compartment
2822 which contains ejection charges or motors.
2826 <title>Ground Testing</title>
2828 The most important aspect of any installation is careful
2829 ground testing. Bringing an air-frame up to the LCO table which
2830 hasn't been ground tested can lead to delays or ejection
2831 charges firing on the pad, or, even worse, a recovery system
2835 Do a 'full systems' test that includes wiring up all igniters
2836 without any BP and turning on all of the electronics in flight
2837 mode. This will catch any mistakes in wiring and any residual
2838 RFI issues that might accidentally fire igniters at the wrong
2839 time. Let the air-frame sit for several minutes, checking for
2840 adequate telemetry signal strength and GPS lock. If any igniters
2841 fire unexpectedly, find and resolve the issue before loading any
2845 Ground test the ejection charges. Prepare the rocket for
2846 flight, loading ejection charges and igniters. Completely
2847 assemble the air-frame and then use the 'Fire Igniters'
2848 interface through a TeleDongle to command each charge to
2849 fire. Make sure the charge is sufficient to robustly separate
2850 the air-frame and deploy the recovery system.
2855 <title>Updating Device Firmware</title>
2857 TeleMega, TeleMetrum v2 and EasyMini are all programmed directly
2858 over their USB connectors (self programming). TeleMetrum v1, TeleMini and
2859 TeleDongle are all programmed by using another device as a
2860 programmer (pair programming). It's important to recognize which
2861 kind of devices you have before trying to reprogram them.
2864 You may wish to begin by ensuring you have current firmware images.
2865 These are distributed as part of the AltOS software bundle that
2866 also includes the AltosUI ground station program. Newer ground
2867 station versions typically work fine with older firmware versions,
2868 so you don't need to update your devices just to try out new
2869 software features. You can always download the most recent
2870 version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
2873 We recommend updating the altimeter first, before updating TeleDongle.
2876 Self-programmable devices (TeleMega, TeleMetrum v2 and EasyMini)
2877 are reprogrammed by connecting them to your computer over USB
2881 Updating TeleMega, TeleMetrum v2 or EasyMini Firmware
2883 <orderedlist inheritnum='inherit' numeration='arabic'>
2886 Attach a battery and power switch to the target
2887 device. Power up the device.
2892 Using a Micro USB cable, connect the target device to your
2893 computer's USB socket.
2898 Run AltosUI, and select 'Flash Image' from the File menu.
2903 Select the target device in the Device Selection dialog.
2908 Select the image you want to flash to the device, which
2909 should have a name in the form
2910 <product>-v<product-version>-<software-version>.ihx, such
2911 as TeleMega-v1.0-1.3.0.ihx.
2916 Make sure the configuration parameters are reasonable
2917 looking. If the serial number and/or RF configuration
2918 values aren't right, you'll need to change them.
2923 Hit the 'OK' button and the software should proceed to flash
2924 the device with new firmware, showing a progress bar.
2929 Verify that the device is working by using the 'Configure
2930 Altimeter' item to check over the configuration.
2935 <title>Recovering From Self-Flashing Failure</title>
2937 If the firmware loading fails, it can leave the device
2938 unable to boot. Not to worry, you can force the device to
2939 start the boot loader instead, which will let you try to
2940 flash the device again.
2943 On each device, connecting two pins from one of the exposed
2944 connectors will force the boot loader to start, even if the
2945 regular operating system has been corrupted in some way.
2949 <term>TeleMega</term>
2952 Connect pin 6 and pin 1 of the companion connector. Pin 1
2953 can be identified by the square pad around it, and then
2954 the pins could sequentially across the board. Be very
2955 careful to <emphasis>not</emphasis> short pin 8 to
2956 anything as that is connected directly to the battery. Pin
2957 7 carries 3.3V and the board will crash if that is
2958 connected to pin 1, but shouldn't damage the board.
2963 <term>TeleMetrum v2</term>
2966 Connect pin 6 and pin 1 of the companion connector. Pin 1
2967 can be identified by the square pad around it, and then
2968 the pins could sequentially across the board. Be very
2969 careful to <emphasis>not</emphasis> short pin 8 to
2970 anything as that is connected directly to the battery. Pin
2971 7 carries 3.3V and the board will crash if that is
2972 connected to pin 1, but shouldn't damage the board.
2977 <term>EasyMini</term>
2980 Connect pin 6 and pin 1 of the debug connector, which is
2981 the six holes next to the beeper. Pin 1 can be identified
2982 by the square pad around it, and then the pins could
2983 sequentially across the board, making Pin 6 the one on the
2984 other end of the row.
2992 <title>Pair Programming</title>
2994 The big concept to understand is that you have to use a
2995 TeleMega, TeleMetrum or TeleDongle as a programmer to update a
2996 pair programmed device. Due to limited memory resources in the
2997 cc1111, we don't support programming directly over USB for these
3002 <title>Updating TeleMetrum v1.x Firmware</title>
3003 <orderedlist inheritnum='inherit' numeration='arabic'>
3006 Find the 'programming cable' that you got as part of the starter
3007 kit, that has a red 8-pin MicroMaTch connector on one end and a
3008 red 4-pin MicroMaTch connector on the other end.
3013 Take the 2 screws out of the TeleDongle case to get access
3014 to the circuit board.
3019 Plug the 8-pin end of the programming cable to the
3020 matching connector on the TeleDongle, and the 4-pin end to the
3021 matching connector on the TeleMetrum.
3022 Note that each MicroMaTch connector has an alignment pin that
3023 goes through a hole in the PC board when you have the cable
3029 Attach a battery to the TeleMetrum board.
3034 Plug the TeleDongle into your computer's USB port, and power
3040 Run AltosUI, and select 'Flash Image' from the File menu.
3045 Pick the TeleDongle device from the list, identifying it as the
3051 Select the image you want put on the TeleMetrum, which should have a
3052 name in the form telemetrum-v1.2-1.0.0.ihx. It should be visible
3053 in the default directory, if not you may have to poke around
3054 your system to find it.
3059 Make sure the configuration parameters are reasonable
3060 looking. If the serial number and/or RF configuration
3061 values aren't right, you'll need to change them.
3066 Hit the 'OK' button and the software should proceed to flash
3067 the TeleMetrum with new firmware, showing a progress bar.
3072 Confirm that the TeleMetrum board seems to have updated OK, which you
3073 can do by plugging in to it over USB and using a terminal program
3074 to connect to the board and issue the 'v' command to check
3080 If something goes wrong, give it another try.
3086 <title>Updating TeleMini Firmware</title>
3087 <orderedlist inheritnum='inherit' numeration='arabic'>
3090 You'll need a special 'programming cable' to reprogram the
3091 TeleMini. It's available on the Altus Metrum web store, or
3092 you can make your own using an 8-pin MicroMaTch connector on
3093 one end and a set of four pins on the other.
3098 Take the 2 screws out of the TeleDongle case to get access
3099 to the circuit board.
3104 Plug the 8-pin end of the programming cable to the matching
3105 connector on the TeleDongle, and the 4-pins into the holes
3106 in the TeleMini circuit board. Note that the MicroMaTch
3107 connector has an alignment pin that goes through a hole in
3108 the PC board when you have the cable oriented correctly, and
3109 that pin 1 on the TeleMini board is marked with a square pad
3110 while the other pins have round pads.
3115 Attach a battery to the TeleMini board.
3120 Plug the TeleDongle into your computer's USB port, and power
3126 Run AltosUI, and select 'Flash Image' from the File menu.
3131 Pick the TeleDongle device from the list, identifying it as the
3137 Select the image you want put on the TeleMini, which should have a
3138 name in the form telemini-v1.0-1.0.0.ihx. It should be visible
3139 in the default directory, if not you may have to poke around
3140 your system to find it.
3145 Make sure the configuration parameters are reasonable
3146 looking. If the serial number and/or RF configuration
3147 values aren't right, you'll need to change them.
3152 Hit the 'OK' button and the software should proceed to flash
3153 the TeleMini with new firmware, showing a progress bar.
3158 Confirm that the TeleMini board seems to have updated OK, which you
3159 can do by configuring it over the radio link through the TeleDongle, or
3160 letting it come up in “flight” mode and listening for telemetry.
3165 If something goes wrong, give it another try.
3171 <title>Updating TeleDongle Firmware</title>
3173 Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
3174 firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
3176 <orderedlist inheritnum='inherit' numeration='arabic'>
3179 Find the 'programming cable' that you got as part of the starter
3180 kit, that has a red 8-pin MicroMaTch connector on one end and a
3181 red 4-pin MicroMaTch connector on the other end.
3186 Find the USB cable that you got as part of the starter kit, and
3187 plug the “mini” end in to the mating connector on TeleMetrum or TeleDongle.
3192 Take the 2 screws out of the TeleDongle case to get access
3193 to the circuit board.
3198 Plug the 8-pin end of the programming cable to the
3199 matching connector on the programmer, and the 4-pin end to the
3200 matching connector on the TeleDongle.
3201 Note that each MicroMaTch connector has an alignment pin that
3202 goes through a hole in the PC board when you have the cable
3208 Attach a battery to the TeleMetrum board if you're using one.
3213 Plug both the programmer and the TeleDongle into your computer's USB
3214 ports, and power up the programmer.
3219 Run AltosUI, and select 'Flash Image' from the File menu.
3224 Pick the programmer device from the list, identifying it as the
3230 Select the image you want put on the TeleDongle, which should have a
3231 name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
3232 in the default directory, if not you may have to poke around
3233 your system to find it.
3238 Make sure the configuration parameters are reasonable
3239 looking. If the serial number and/or RF configuration
3240 values aren't right, you'll need to change them. The TeleDongle
3241 serial number is on the “bottom” of the circuit board, and can
3242 usually be read through the translucent blue plastic case without
3243 needing to remove the board from the case.
3248 Hit the 'OK' button and the software should proceed to flash
3249 the TeleDongle with new firmware, showing a progress bar.
3254 Confirm that the TeleDongle board seems to have updated OK, which you
3255 can do by plugging in to it over USB and using a terminal program
3256 to connect to the board and issue the 'v' command to check
3257 the version, etc. Once you're happy, remove the programming cable
3258 and put the cover back on the TeleDongle.
3263 If something goes wrong, give it another try.
3268 Be careful removing the programming cable from the locking 8-pin
3269 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
3270 screwdriver or knife blade to gently pry the locking ears out
3271 slightly to extract the connector. We used a locking connector on
3272 TeleMetrum to help ensure that the cabling to companion boards
3273 used in a rocket don't ever come loose accidentally in flight.
3278 <title>Hardware Specifications</title>
3281 TeleMega Specifications
3286 Recording altimeter for model rocketry.
3291 Supports dual deployment and four auxiliary pyro channels
3292 (a total of 6 events).
3297 70cm 40mW ham-band transceiver for telemetry down-link.
3302 Barometric pressure sensor good to 100k feet MSL.
3307 1-axis high-g accelerometer for motor characterization, capable of
3313 9-axis IMU including integrated 3-axis accelerometer,
3314 3-axis gyroscope and 3-axis magnetometer.
3319 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
3324 On-board 8 Megabyte non-volatile memory for flight data storage.
3329 USB interface for battery charging, configuration, and data recovery.
3334 Fully integrated support for Li-Po rechargeable batteries.
3339 Uses Li-Po to fire e-matches, can be modified to support
3340 optional separate pyro battery if needed.
3345 3.25 x 1.25 inch board designed to fit inside 38mm air-frame coupler tube.
3352 TeleMetrum v2 Specifications
3357 Recording altimeter for model rocketry.
3362 Supports dual deployment (can fire 2 ejection charges).
3367 70cm, 40mW ham-band transceiver for telemetry down-link.
3372 Barometric pressure sensor good to 100k feet MSL.
3377 1-axis high-g accelerometer for motor characterization, capable of
3383 On-board, integrated uBlox Max 7 GPS receiver with 5Hz update rate capability.
3388 On-board 8 Megabyte non-volatile memory for flight data storage.
3393 USB interface for battery charging, configuration, and data recovery.
3398 Fully integrated support for Li-Po rechargeable batteries.
3403 Uses Li-Po to fire e-matches, can be modified to support
3404 optional separate pyro battery if needed.
3409 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
3415 <title>TeleMetrum v1 Specifications</title>
3419 Recording altimeter for model rocketry.
3424 Supports dual deployment (can fire 2 ejection charges).
3429 70cm, 10mW ham-band transceiver for telemetry down-link.
3434 Barometric pressure sensor good to 45k feet MSL.
3439 1-axis high-g accelerometer for motor characterization, capable of
3440 +/- 50g using default part.
3445 On-board, integrated GPS receiver with 5Hz update rate capability.
3450 On-board 1 megabyte non-volatile memory for flight data storage.
3455 USB interface for battery charging, configuration, and data recovery.
3460 Fully integrated support for Li-Po rechargeable batteries.
3465 Uses Li-Po to fire e-matches, can be modified to support
3466 optional separate pyro battery if needed.
3471 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
3478 TeleMini v2.0 Specifications
3483 Recording altimeter for model rocketry.
3488 Supports dual deployment (can fire 2 ejection charges).
3493 70cm, 10mW ham-band transceiver for telemetry down-link.
3498 Barometric pressure sensor good to 100k feet MSL.
3503 On-board 1 megabyte non-volatile memory for flight data storage.
3508 USB interface for configuration, and data recovery.
3513 Support for Li-Po rechargeable batteries (using an
3514 external charger), or any 3.7-15V external battery.
3519 Uses Li-Po to fire e-matches, can be modified to support
3520 optional separate pyro battery if needed.
3525 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
3532 TeleMini v1.0 Specifications
3537 Recording altimeter for model rocketry.
3542 Supports dual deployment (can fire 2 ejection charges).
3547 70cm, 10mW ham-band transceiver for telemetry down-link.
3552 Barometric pressure sensor good to 45k feet MSL.
3557 On-board 5 kilobyte non-volatile memory for flight data storage.
3562 RF interface for configuration, and data recovery.
3567 Support for Li-Po rechargeable batteries, using an external charger.
3572 Uses Li-Po to fire e-matches, can be modified to support
3573 optional separate pyro battery if needed.
3578 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube.
3585 EasyMini Specifications
3590 Recording altimeter for model rocketry.
3595 Supports dual deployment (can fire 2 ejection charges).
3600 Barometric pressure sensor good to 100k feet MSL.
3605 On-board 1 megabyte non-volatile memory for flight data storage.
3610 USB interface for configuration, and data recovery.
3615 Support for Li-Po rechargeable batteries (using an
3616 external charger), or any 3.7-15V external battery.
3621 Uses Li-Po to fire e-matches, can be modified to support
3622 optional separate pyro battery if needed.
3627 1.5 x .8 inch board designed to fit inside 24mm air-frame coupler tube.
3636 TeleMetrum seems to shut off when disconnected from the
3637 computer. Make sure the battery is adequately charged. Remember the
3638 unit will pull more power than the USB port can deliver before the
3639 GPS enters “locked” mode. The battery charges best when TeleMetrum
3643 It's impossible to stop the TeleDongle when it's in “p” mode, I have
3644 to unplug the USB cable? Make sure you have tried to “escape out” of
3645 this mode. If this doesn't work the reboot procedure for the
3646 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
3647 outgoing buffer IF your “escape out” ('~~') does not work.
3648 At this point using either 'ao-view' (or possibly
3649 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
3653 The amber LED (on the TeleMetrum) lights up when both
3654 battery and USB are connected. Does this mean it's charging?
3655 Yes, the yellow LED indicates the charging at the 'regular' rate.
3656 If the led is out but the unit is still plugged into a USB port,
3657 then the battery is being charged at a 'trickle' rate.
3660 There are no “dit-dah-dah-dit” sound or lights like the manual mentions?
3661 That's the “pad” mode. Weak batteries might be the problem.
3662 It is also possible that the TeleMetrum is horizontal and the output
3663 is instead a “dit-dit” meaning 'idle'. For TeleMini, it's possible that
3664 it received a command packet which would have left it in “pad” mode.
3667 How do I save flight data?
3668 Live telemetry is written to file(s) whenever AltosUI is connected
3669 to the TeleDongle. The file area defaults to ~/TeleMetrum
3670 but is easily changed using the menus in AltosUI. The files that
3671 are written end in '.telem'. The after-flight
3672 data-dumped files will end in .eeprom and represent continuous data
3673 unlike the .telem files that are subject to losses
3674 along the RF data path.
3675 See the above instructions on what and how to save the eeprom stored
3676 data after physically retrieving your altimeter. Make sure to save
3677 the on-board data after each flight; while the TeleMetrum can store
3678 multiple flights, you never know when you'll lose the altimeter...
3682 <title>Notes for Older Software</title>
3685 Before AltosUI was written, using Altus Metrum devices required
3686 some finesse with the Linux command line. There was a limited
3687 GUI tool, ao-view, which provided functionality similar to the
3688 Monitor Flight window in AltosUI, but everything else was a
3689 fairly 80's experience. This appendix includes documentation for
3690 using that software.
3694 Both TeleMetrum and TeleDongle can be directly communicated
3695 with using USB ports. The first thing you should try after getting
3696 both units plugged into to your computer's USB port(s) is to run
3697 'ao-list' from a terminal-window to see what port-device-name each
3698 device has been assigned by the operating system.
3699 You will need this information to access the devices via their
3700 respective on-board firmware and data using other command line
3701 programs in the AltOS software suite.
3704 TeleMini can be communicated with through a TeleDongle device
3705 over the radio link. When first booted, TeleMini listens for a
3706 TeleDongle device and if it receives a packet, it goes into
3707 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be
3708 launched. The easiest way to get it talking is to start the
3709 communication link on the TeleDongle and the power up the
3713 To access the device's firmware for configuration you need a terminal
3714 program such as you would use to talk to a modem. The software
3715 authors prefer using the program 'cu' which comes from the UUCP package
3716 on most Unix-like systems such as Linux. An example command line for
3717 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
3718 indicated from running the
3719 ao-list program. Another reasonable terminal program for Linux is
3720 'cutecom'. The default 'escape'
3721 character used by CU (i.e. the character you use to
3722 issue commands to cu itself instead of sending the command as input
3723 to the connected device) is a '~'. You will need this for use in
3724 only two different ways during normal operations. First is to exit
3725 the program by sending a '~.' which is called a 'escape-disconnect'
3726 and allows you to close-out from 'cu'. The
3727 second use will be outlined later.
3730 All of the Altus Metrum devices share the concept of a two level
3731 command set in their firmware.
3732 The first layer has several single letter commands. Once
3733 you are using 'cu' (or 'cutecom') sending (typing) a '?'
3734 returns a full list of these
3735 commands. The second level are configuration sub-commands accessed
3736 using the 'c' command, for
3737 instance typing 'c?' will give you this second level of commands
3738 (all of which require the
3739 letter 'c' to access). Please note that most configuration options
3740 are stored only in Flash memory; TeleDongle doesn't provide any storage
3741 for these options and so they'll all be lost when you unplug it.
3744 Try setting these configuration ('c' or second level menu) values. A good
3745 place to start is by setting your call sign. By default, the boards
3746 use 'N0CALL' which is cute, but not exactly legal!
3747 Spend a few minutes getting comfortable with the units, their
3748 firmware, and 'cu' (or possibly 'cutecom').
3749 For instance, try to send
3750 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
3751 Verify you can connect and disconnect from the units while in your
3752 terminal program by sending the escape-disconnect mentioned above.
3755 To set the radio frequency, use the 'c R' command to specify the
3756 radio transceiver configuration parameter. This parameter is computed
3757 using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
3758 the standard calibration reference frequency, 'S', (normally 434.550MHz):
3762 Round the result to the nearest integer value.
3763 As with all 'c' sub-commands, follow this with a 'c w' to write the
3764 change to the parameter block in the on-board flash on
3765 your altimeter board if you want the change to stay in place across reboots.
3768 To set the apogee delay, use the 'c d' command.
3769 As with all 'c' sub-commands, follow this with a 'c w' to write the
3770 change to the parameter block in the on-board DataFlash chip.
3773 To set the main deployment altitude, use the 'c m' command.
3774 As with all 'c' sub-commands, follow this with a 'c w' to write the
3775 change to the parameter block in the on-board DataFlash chip.
3778 To calibrate the radio frequency, connect the UHF antenna port to a
3779 frequency counter, set the board to 434.550MHz, and use the 'C'
3780 command to generate a CW carrier. Wait for the transmitter temperature
3781 to stabilize and the frequency to settle down.
3782 Then, divide 434.550 MHz by the
3783 measured frequency and multiply by the current radio cal value show
3784 in the 'c s' command. For an unprogrammed board, the default value
3785 is 1186611. Take the resulting integer and program it using the 'c f'
3786 command. Testing with the 'C' command again should show a carrier
3787 within a few tens of Hertz of the intended frequency.
3788 As with all 'c' sub-commands, follow this with a 'c w' to write the
3789 change to the parameter block in the on-board DataFlash chip.
3792 Note that the 'reboot' command, which is very useful on the altimeters,
3793 will likely just cause problems with the dongle. The *correct* way
3794 to reset the dongle is just to unplug and re-plug it.
3797 A fun thing to do at the launch site and something you can do while
3798 learning how to use these units is to play with the radio link access
3799 between an altimeter and the TeleDongle. Be aware that you *must* create
3800 some physical separation between the devices, otherwise the link will
3801 not function due to signal overload in the receivers in each device.
3804 Now might be a good time to take a break and read the rest of this
3805 manual, particularly about the two “modes” that the altimeters
3806 can be placed in. TeleMetrum uses the position of the device when booting
3807 up will determine whether the unit is in “pad” or “idle” mode. TeleMini
3808 enters “idle” mode when it receives a command packet within the first 5 seconds
3809 of being powered up, otherwise it enters “pad” mode.
3812 You can access an altimeter in idle mode from the TeleDongle's USB
3813 connection using the radio link
3814 by issuing a 'p' command to the TeleDongle. Practice connecting and
3815 disconnecting ('~~' while using 'cu') from the altimeter. If
3816 you cannot escape out of the “p” command, (by using a '~~' when in
3817 CU) then it is likely that your kernel has issues. Try a newer version.
3820 Using this radio link allows you to configure the altimeter, test
3821 fire e-matches and igniters from the flight line, check pyro-match
3822 continuity and so forth. You can leave the unit turned on while it
3823 is in 'idle mode' and then place the
3824 rocket vertically on the launch pad, walk away and then issue a
3825 reboot command. The altimeter will reboot and start sending data
3826 having changed to the “pad” mode. If the TeleDongle is not receiving
3827 this data, you can disconnect 'cu' from the TeleDongle using the
3828 procedures mentioned above and THEN connect to the TeleDongle from
3829 inside 'ao-view'. If this doesn't work, disconnect from the
3830 TeleDongle, unplug it, and try again after plugging it back in.
3833 In order to reduce the chance of accidental firing of pyrotechnic
3834 charges, the command to fire a charge is intentionally somewhat
3835 difficult to type, and the built-in help is slightly cryptic to
3836 prevent accidental echoing of characters from the help text back at
3837 the board from firing a charge. The command to fire the apogee
3838 drogue charge is 'i DoIt drogue' and the command to fire the main
3839 charge is 'i DoIt main'.
3842 On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
3843 and 'ao-view' will both auditorily announce and visually indicate
3845 Now you can launch knowing that you have a good data path and
3846 good satellite lock for flight data and recovery. Remember
3847 you MUST tell ao-view to connect to the TeleDongle explicitly in
3848 order for ao-view to be able to receive data.
3851 The altimeters provide RDF (radio direction finding) tones on
3852 the pad, during descent and after landing. These can be used to
3853 locate the rocket using a directional antenna; the signal
3854 strength providing an indication of the direction from receiver to rocket.
3857 TeleMetrum also provides GPS tracking data, which can further simplify
3858 locating the rocket once it has landed. (The last good GPS data
3859 received before touch-down will be on the data screen of 'ao-view'.)
3862 Once you have recovered the rocket you can download the eeprom
3863 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
3864 either a USB cable or over the radio link using TeleDongle.
3865 And by following the man page for 'ao-postflight' you can create
3866 various data output reports, graphs, and even KML data to see the
3867 flight trajectory in Google-earth. (Moving the viewing angle making
3868 sure to connect the yellow lines while in Google-earth is the proper
3872 As for ao-view.... some things are in the menu but don't do anything
3873 very useful. The developers have stopped working on ao-view to focus
3874 on a new, cross-platform ground station program. So ao-view may or
3875 may not be updated in the future. Mostly you just use
3876 the Log and Device menus. It has a wonderful display of the incoming
3877 flight data and I am sure you will enjoy what it has to say to you
3878 once you enable the voice output!
3882 <title>Drill Templates</title>
3884 These images, when printed, provide precise templates for the
3885 mounting holes in Altus Metrum flight computers
3888 <title>TeleMega template</title>
3890 TeleMega has overall dimensions of 1.250 x 3.250 inches, and
3891 the mounting holes are sized for use with 4-40 or M3 screws.
3893 <mediaobject id="TeleMegaTemplate">
3895 <imagedata format="SVG" fileref="telemega-outline.svg"/>
3900 <title>TeleMetrum template</title>
3902 TeleMetrum has overall dimensions of 1.000 x 2.750 inches, and the
3903 mounting holes are sized for use with 4-40 or M3 screws.
3905 <mediaobject id="TeleMetrumTemplate">
3907 <imagedata format="SVG" fileref="telemetrum.svg"/>
3912 <title>TeleMini v2/EasyMini template</title>
3914 TeleMini v2 and EasyMini have overall dimensions of 0.800 x 1.500 inches, and the
3915 mounting holes are sized for use with 4-40 or M3 screws.
3917 <mediaobject id="MiniTemplate">
3919 <imagedata format="SVG" fileref="easymini-outline.svg"/>
3924 <title>TeleMini v1 template</title>
3926 TeleMini has overall dimensions of 0.500 x 1.500 inches, and the
3927 mounting holes are sized for use with 2-56 or M2 screws.
3929 <mediaobject id="TeleMiniTemplate">
3931 <imagedata format="SVG" fileref="telemini.svg"/>
3937 <title>Calibration</title>
3939 There are only two calibrations required for TeleMetrum and
3940 TeleMega, and only one for TeleDongle, TeleMini and EasyMini.
3941 All boards are shipped from the factory pre-calibrated, but
3942 the procedures are documented here in case they are ever
3943 needed. Re-calibration is not supported by AltosUI, you must
3944 connect to the board with a serial terminal program and
3945 interact directly with the on-board command interpreter to
3949 <title>Radio Frequency</title>
3951 The radio frequency is synthesized from a clock based on the
3952 crystal on the board. The actual frequency of this oscillator
3953 must be measured to generate a calibration constant. While our
3955 bandwidth is wide enough to allow boards to communicate even when
3956 their oscillators are not on exactly the same frequency, performance
3957 is best when they are closely matched.
3958 Radio frequency calibration requires a calibrated frequency counter.
3959 Fortunately, once set, the variation in frequency due to aging and
3960 temperature changes is small enough that re-calibration by customers
3961 should generally not be required.
3964 To calibrate the radio frequency, connect the UHF antenna
3965 port to a frequency counter, set the board to 434.550MHz,
3966 and use the 'C' command in the on-board command interpreter
3967 to generate a CW carrier. For USB-enabled boards, this is
3968 best done over USB. For TeleMini v1, note that the only way
3969 to escape the 'C' command is via power cycle since the board
3970 will no longer be listening for commands once it starts
3971 generating a CW carrier.
3974 Wait for the transmitter temperature to stabilize and the frequency
3975 to settle down. Then, divide 434.550 MHz by the
3976 measured frequency and multiply by the current radio cal value show
3977 in the 'c s' command. For an unprogrammed board, the default value
3978 is 1186611. Take the resulting integer and program it using the 'c f'
3979 command. Testing with the 'C' command again should show a carrier
3980 within a few tens of Hertz of the intended frequency.
3981 As with all 'c' sub-commands, follow this with a 'c w' to write the
3982 change to the parameter block in the on-board storage chip.
3985 Note that any time you re-do the radio frequency calibration, the
3986 radio frequency is reset to the default 434.550 Mhz. If you want
3987 to use another frequency, you will have to set that again after
3988 calibration is completed.
3992 <title>TeleMetrum and TeleMega Accelerometers</title>
3994 While barometric sensors are factory-calibrated,
3995 accelerometers are not, and so each must be calibrated once
3996 installed in a flight computer. Explicitly calibrating the
3997 accelerometers also allows us to load any compatible device.
3998 We perform a two-point calibration using gravity.
4001 To calibrate the acceleration sensor, use the 'c a 0' command. You
4002 will be prompted to orient the board vertically with the UHF antenna
4003 up and press a key, then to orient the board vertically with the
4004 UHF antenna down and press a key. Note that the accuracy of this
4005 calibration depends primarily on how perfectly vertical and still
4006 the board is held during the cal process. As with all 'c'
4007 sub-commands, follow this with a 'c w' to write the
4008 change to the parameter block in the on-board DataFlash chip.
4011 The +1g and -1g calibration points are included in each telemetry
4012 frame and are part of the header stored in onboard flash to be
4013 downloaded after flight. We always store and return raw ADC
4014 samples for each sensor... so nothing is permanently “lost” or
4015 “damaged” if the calibration is poor.
4018 In the unlikely event an accel cal goes badly, it is possible
4019 that TeleMetrum or TeleMega may always come up in 'pad mode'
4020 and as such not be listening to either the USB or radio link.
4021 If that happens, there is a special hook in the firmware to
4022 force the board back in to 'idle mode' so you can re-do the
4023 cal. To use this hook, you just need to ground the SPI clock
4024 pin at power-on. This pin is available as pin 2 on the 8-pin
4025 companion connector, and pin 1 is ground. So either
4026 carefully install a fine-gauge wire jumper between the two
4027 pins closest to the index hole end of the 8-pin connector, or
4028 plug in the programming cable to the 8-pin connector and use
4029 a small screwdriver or similar to short the two pins closest
4030 to the index post on the 4-pin end of the programming cable,
4031 and power up the board. It should come up in 'idle mode'
4032 (two beeps), allowing a re-cal.
4037 <title>Release Notes</title>
4039 <title>Version 1.3</title>
4041 xmlns:xi="http://www.w3.org/2001/XInclude"
4042 href="release-notes-1.3.xsl"
4043 xpointer="xpointer(/article/*)"/>
4046 <title>Version 1.2.1</title>
4048 xmlns:xi="http://www.w3.org/2001/XInclude"
4049 href="release-notes-1.2.1.xsl"
4050 xpointer="xpointer(/article/*)"/>
4053 <title>Version 1.2</title>
4055 xmlns:xi="http://www.w3.org/2001/XInclude"
4056 href="release-notes-1.2.xsl"
4057 xpointer="xpointer(/article/*)"/>
4060 <title>Version 1.1.1</title>
4062 xmlns:xi="http://www.w3.org/2001/XInclude"
4063 href="release-notes-1.1.1.xsl"
4064 xpointer="xpointer(/article/*)"/>
4067 <title>Version 1.1</title>
4069 xmlns:xi="http://www.w3.org/2001/XInclude"
4070 href="release-notes-1.1.xsl"
4071 xpointer="xpointer(/article/*)"/>
4074 <title>Version 1.0.1</title>
4076 xmlns:xi="http://www.w3.org/2001/XInclude"
4077 href="release-notes-1.0.1.xsl"
4078 xpointer="xpointer(/article/*)"/>
4081 <title>Version 0.9.2</title>
4083 xmlns:xi="http://www.w3.org/2001/XInclude"
4084 href="release-notes-0.9.2.xsl"
4085 xpointer="xpointer(/article/*)"/>
4088 <title>Version 0.9</title>
4090 xmlns:xi="http://www.w3.org/2001/XInclude"
4091 href="release-notes-0.9.xsl"
4092 xpointer="xpointer(/article/*)"/>
4095 <title>Version 0.8</title>
4097 xmlns:xi="http://www.w3.org/2001/XInclude"
4098 href="release-notes-0.8.xsl"
4099 xpointer="xpointer(/article/*)"/>
4102 <title>Version 0.7.1</title>
4104 xmlns:xi="http://www.w3.org/2001/XInclude"
4105 href="release-notes-0.7.1.xsl"
4106 xpointer="xpointer(/article/*)"/>
4111 <!-- LocalWords: Altusmetrum
projects / fw / altos / blob