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5 <title>The Altus Metrum System</title>
6 <subtitle>An Owner's Manual for TeleMetrum, TeleMini and TeleDongle Devices</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>1.2</revnumber>
40 <date>14 April 2013</date>
42 Updated for software version 1.2. Version 1.2 adds support
43 for TeleBT and AltosDroid. It also adds a few minor features
44 and fixes a few minor bugs in AltosUI and the AltOS firmware.
48 <revnumber>1.1.1</revnumber>
49 <date>16 September 2012</date>
51 Updated for software version 1.1.1 Version 1.1.1 fixes a few
52 bugs found in version 1.1.
56 <revnumber>1.1</revnumber>
57 <date>13 September 2012</date>
59 Updated for software version 1.1. Version 1.1 has new
60 features but is otherwise compatible with version 1.0.
64 <revnumber>1.0</revnumber>
65 <date>24 August 2011</date>
67 Updated for software version 1.0. Note that 1.0 represents a
68 telemetry format change, meaning both ends of a link
69 (TeleMetrum/TeleMini and TeleDongle) must be updated or
70 communications will fail.
74 <revnumber>0.9</revnumber>
75 <date>18 January 2011</date>
77 Updated for software version 0.9. Note that 0.9 represents a
78 telemetry format change, meaning both ends of a link (TeleMetrum and
79 TeleDongle) must be updated or communications will fail.
83 <revnumber>0.8</revnumber>
84 <date>24 November 2010</date>
85 <revremark>Updated for software version 0.8 </revremark>
91 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing "The
92 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
93 Kit" which formed the basis of the original Getting Started chapter
94 in this manual. Bob was one of our first customers for a production
95 TeleMetrum, and his continued enthusiasm and contributions
96 are immensely gratifying and highly appreciated!
99 And thanks to Anthony (AJ) Towns for major contributions including
100 the AltosUI graphing and site map code and associated documentation.
101 Free software means that our customers and friends can become our
102 collaborators, and we certainly appreciate this level of
106 Have fun using these products, and we hope to meet all of you
107 out on the rocket flight line somewhere.
110 NAR #87103, TRA #12201
112 Keith Packard, KD7SQG
113 NAR #88757, TRA #12200
118 <title>Introduction and Overview</title>
120 Welcome to the Altus Metrum community! Our circuits and software reflect
121 our passion for both hobby rocketry and Free Software. We hope their
122 capabilities and performance will delight you in every way, but by
123 releasing all of our hardware and software designs under open licenses,
124 we also hope to empower you to take as active a role in our collective
128 The first device created for our community was TeleMetrum, a dual
129 deploy altimeter with fully integrated GPS and radio telemetry
130 as standard features, and a "companion interface" that will
131 support optional capabilities in the future.
134 Our second device was TeleMini, a dual deploy altimeter with
135 radio telemetry and radio direction finding. This device is only
136 13mm by 38mm (½ inch by 1½ inches) and can fit easily in an 18mm
140 Complementing TeleMetrum and TeleMini is TeleDongle, a USB to RF
141 interface for communicating with the altimeters. Combined with your
142 choice of antenna and
143 notebook computer, TeleDongle and our associated user interface software
144 form a complete ground station capable of logging and displaying in-flight
145 telemetry, aiding rocket recovery, then processing and archiving flight
146 data for analysis and review.
149 More products will be added to the Altus Metrum family over time, and
150 we currently envision that this will be a single, comprehensive manual
151 for the entire product family.
155 <title>Getting Started</title>
157 The first thing to do after you check the inventory of parts in your
158 "starter kit" is to charge the battery.
161 The TeleMetrum battery can be charged by plugging it into the
162 corresponding socket of the TeleMetrum and then using the USB A to
164 cable to plug the TeleMetrum into your computer's USB socket. The
165 TeleMetrum circuitry will charge the battery whenever it is plugged
166 in, because the TeleMetrum's on-off switch does NOT control the
170 When the GPS chip is initially searching for
171 satellites, TeleMetrum will consume more current than it can pull
172 from the USB port, so the battery must be attached in order to get
173 satellite lock. Once GPS is locked, the current consumption goes back
174 down enough to enable charging while
175 running. So it's a good idea to fully charge the battery as your
176 first item of business so there is no issue getting and maintaining
177 satellite lock. The yellow charge indicator led will go out when the
178 battery is nearly full and the charger goes to trickle charge. It
179 can take several hours to fully recharge a deeply discharged battery.
182 The TeleMini battery can be charged by disconnecting it from the
183 TeleMini board and plugging it into a standalone battery charger
184 such as the LipoCharger product included in TeleMini Starter Kits,
185 and connecting that via a USB cable to a laptop or other USB
189 The other active device in the starter kit is the TeleDongle USB to
190 RF interface. If you plug it in to your Mac or Linux computer it should
191 "just work", showing up as a serial port device. Windows systems need
192 driver information that is part of the AltOS download to know that the
193 existing USB modem driver will work. We therefore recommend installing
194 our software before plugging in TeleDongle if you are using a Windows
195 computer. If you are using Linux and are having problems, try moving
196 to a fresher kernel (2.6.33 or newer), as the USB serial driver had
197 ugly bugs in some earlier versions.
200 Next you should obtain and install the AltOS software. These include
201 the AltosUI ground station program, current firmware images for
202 TeleMetrum, TeleMini and TeleDongle, and a number of standalone
203 utilities that are rarely needed. Pre-built binary packages are
204 available for Linux, Microsoft Windows, and recent MacOSX versions.
205 Full source code and build instructions are also available.
206 The latest version may always be downloaded from
207 <ulink url="http://altusmetrum.org/AltOS"/>.
211 <title>Handling Precautions</title>
213 All Altus Metrum products are sophisticated electronic devices.
214 When handled gently and properly installed in an air-frame, they
215 will deliver impressive results. However, as with all electronic
216 devices, there are some precautions you must take.
219 The Lithium Polymer rechargeable batteries have an
220 extraordinary power density. This is great because we can fly with
221 much less battery mass than if we used alkaline batteries or previous
222 generation rechargeable batteries... but if they are punctured
223 or their leads are allowed to short, they can and will release their
225 Thus we recommend that you take some care when handling our batteries
226 and consider giving them some extra protection in your air-frame. We
227 often wrap them in suitable scraps of closed-cell packing foam before
228 strapping them down, for example.
231 The barometric sensors used on both TeleMetrum and TeleMini are
232 sensitive to sunlight. In normal TeleMetrum mounting situations, it
233 and all of the other surface mount components
234 are "down" towards whatever the underlying mounting surface is, so
235 this is not normally a problem. Please consider this, though, when
236 designing an installation, for example, in an air-frame with a
237 see-through plastic payload bay. It is particularly important to
238 consider this with TeleMini, both because the baro sensor is on the
239 "top" of the board, and because many model rockets with payload bays
240 use clear plastic for the payload bay! Replacing these with an opaque
241 cardboard tube, painting them, or wrapping them with a layer of masking
242 tape are all reasonable approaches to keep the sensor out of direct
246 The barometric sensor sampling port must be able to "breathe",
247 both by not being covered by foam or tape or other materials that might
248 directly block the hole on the top of the sensor, and also by having a
249 suitable static vent to outside air.
252 As with all other rocketry electronics, Altus Metrum altimeters must
253 be protected from exposure to corrosive motor exhaust and ejection
258 <title>Hardware Overview</title>
260 TeleMetrum is a 1 inch by 2.75 inch circuit board. It was designed to
261 fit inside coupler for 29mm air-frame tubing, but using it in a tube that
262 small in diameter may require some creativity in mounting and wiring
263 to succeed! The presence of an accelerometer means TeleMetrum should
264 be aligned along the flight axis of the airframe, and by default the 1/4
265 wave UHF wire antenna should be on the nose-cone end of the board. The
266 antenna wire is about 7 inches long, and wiring for a power switch and
267 the e-matches for apogee and main ejection charges depart from the
268 fin can end of the board, meaning an ideal "simple" avionics
269 bay for TeleMetrum should have at least 10 inches of interior length.
272 TeleMini is a 0.5 inch by 1.5 inch circuit board. It was designed to
273 fit inside an 18mm air-frame tube, but using it in a tube that
274 small in diameter may require some creativity in mounting and wiring
275 to succeed! Since there is no accelerometer, TeleMini can be mounted
276 in any convenient orientation. The default 1/4
277 wave UHF wire antenna attached to the center of one end of
278 the board is about 7 inches long, and wiring for a power switch and
279 the e-matches for apogee and main ejection charges depart from the
280 other end of the board, meaning an ideal "simple" avionics
281 bay for TeleMini should have at least 9 inches of interior length.
284 A typical TeleMetrum or TeleMini installation involves attaching
285 only a suitable Lithium Polymer battery, a single pole switch for
286 power on/off, and two pairs of wires connecting e-matches for the
287 apogee and main ejection charges. All Altus Metrum products are
288 designed for use with single-cell batteries with 3.7 volts nominal.
291 The battery connectors are a standard 2-pin JST connector and
292 match batteries sold by Spark Fun. These batteries are
293 single-cell Lithium Polymer batteries that nominally provide 3.7
294 volts. Other vendors sell similar batteries for RC aircraft
295 using mating connectors, however the polarity for those is
296 generally reversed from the batteries used by Altus Metrum
297 products. In particular, the Tenergy batteries supplied for use
298 in Featherweight flight computers are not compatible with Altus
299 Metrum flight computers or battery chargers. <emphasis>Check
300 polarity and voltage before connecting any battery not purchased
301 from Altus Metrum or Spark Fun.</emphasis>
304 By default, we use the unregulated output of the Li-Po battery directly
305 to fire ejection charges. This works marvelously with standard
306 low-current e-matches like the J-Tek from MJG Technologies, and with
307 Quest Q2G2 igniters. However, if you want or need to use a separate
308 pyro battery, check out the "External Pyro Battery" section in this
309 manual for instructions on how to wire that up. The altimeters are
310 designed to work with an external pyro battery of no more than 15 volts.
313 Ejection charges are wired directly to the screw terminal block
314 at the aft end of the altimeter. You'll need a very small straight
315 blade screwdriver for these screws, such as you might find in a
316 jeweler's screwdriver set.
319 TeleMetrum also uses the screw terminal block for the power
320 switch leads. On TeleMini, the power switch leads are soldered
321 directly to the board and can be connected directly to a switch.
324 For most air-frames, the integrated antennas are more than
325 adequate. However, if you are installing in a carbon-fiber or
326 metal electronics bay which is opaque to RF signals, you may need to
327 use off-board external antennas instead. In this case, you can
328 order an altimeter with an SMA connector for the UHF antenna
329 connection, and, on TeleMetrum, you can unplug the integrated GPS
330 antenna and select an appropriate off-board GPS antenna with
331 cable terminating in a U.FL connector.
335 <title>System Operation</title>
337 <title>Firmware Modes </title>
339 The AltOS firmware build for the altimeters has two
340 fundamental modes, "idle" and "flight". Which of these modes
341 the firmware operates in is determined at start up time. For
342 TeleMetrum, the mode is controlled by the orientation of the
343 rocket (well, actually the board, of course...) at the time
344 power is switched on. If the rocket is "nose up", then
345 TeleMetrum assumes it's on a rail or rod being prepared for
346 launch, so the firmware chooses flight mode. However, if the
347 rocket is more or less horizontal, the firmware instead enters
348 idle mode. Since TeleMini doesn't have an accelerometer we can
349 use to determine orientation, "idle" mode is selected when the
350 board receives a command packet within the first five seconds
351 of operation; if no packet is received, the board enters
355 At power on, you will hear three beeps or see three flashes
356 ("S" in Morse code for start up) and then a pause while
357 the altimeter completes initialization and self test, and decides
358 which mode to enter next.
361 In flight or "pad" mode, the altimeter engages the flight
362 state machine, goes into transmit-only mode to
363 send telemetry, and waits for launch to be detected.
364 Flight mode is indicated by an "di-dah-dah-dit" ("P" for pad)
365 on the beeper or lights, followed by beeps or flashes
366 indicating the state of the pyrotechnic igniter continuity.
367 One beep/flash indicates apogee continuity, two beeps/flashes
368 indicate main continuity, three beeps/flashes indicate both
369 apogee and main continuity, and one longer "brap" sound or
370 rapidly alternating lights indicates no continuity. For a
371 dual deploy flight, make sure you're getting three beeps or
372 flashes before launching! For apogee-only or motor eject
373 flights, do what makes sense.
376 If idle mode is entered, you will hear an audible "di-dit" or see
377 two short flashes ("I" for idle), and the flight state machine is
378 disengaged, thus no ejection charges will fire. The altimeters also
379 listen for the radio link when in idle mode for requests sent via
380 TeleDongle. Commands can be issued to a TeleMetrum in idle mode
382 USB or the radio link equivalently. TeleMini only has the radio link.
383 Idle mode is useful for configuring the altimeter, for extracting data
384 from the on-board storage chip after flight, and for ground testing
388 One "neat trick" of particular value when TeleMetrum is used with
389 very large air-frames, is that you can power the board up while the
390 rocket is horizontal, such that it comes up in idle mode. Then you can
391 raise the air-frame to launch position, and issue a 'reset' command
392 via TeleDongle over the radio link to cause the altimeter to reboot and
393 come up in flight mode. This is much safer than standing on the top
394 step of a rickety step-ladder or hanging off the side of a launch
395 tower with a screw-driver trying to turn on your avionics before
399 TeleMini is configured via the radio link. Of course, that
400 means you need to know the TeleMini radio configuration values
401 or you won't be able to communicate with it. For situations
402 when you don't have the radio configuration values, TeleMini
403 offers an 'emergency recovery' mode. In this mode, TeleMini is
404 configured as follows:
407 Sets the radio frequency to 434.550MHz
410 Sets the radio calibration back to the factory value.
413 Sets the callsign to N0CALL
416 Does not go to 'pad' mode after five seconds.
421 To get into 'emergency recovery' mode, first find the row of
422 four small holes opposite the switch wiring. Using a short
423 piece of small gauge wire, connect the outer two holes
424 together, then power TeleMini up. Once the red LED is lit,
425 disconnect the wire and the board should signal that it's in
426 'idle' mode after the initial five second startup period.
432 TeleMetrum includes a complete GPS receiver. A complete explanation
433 of how GPS works is beyond the scope of this manual, but the bottom
434 line is that the TeleMetrum GPS receiver needs to lock onto at least
435 four satellites to obtain a solid 3 dimensional position fix and know
439 TeleMetrum provides backup power to the GPS chip any time a
440 battery is connected. This allows the receiver to "warm start" on
441 the launch rail much faster than if every power-on were a GPS
442 "cold start". In typical operations, powering up TeleMetrum
443 on the flight line in idle mode while performing final air-frame
444 preparation will be sufficient to allow the GPS receiver to cold
445 start and acquire lock. Then the board can be powered down during
446 RSO review and installation on a launch rod or rail. When the board
447 is turned back on, the GPS system should lock very quickly, typically
448 long before igniter installation and return to the flight line are
453 <title>Controlling An Altimeter Over The Radio Link</title>
455 One of the unique features of the Altus Metrum system is
456 the ability to create a two way command link between TeleDongle
457 and an altimeter using the digital radio transceivers built into
458 each device. This allows you to interact with the altimeter from
459 afar, as if it were directly connected to the computer.
462 Any operation which can be performed with TeleMetrum can
463 either be done with TeleMetrum directly connected to the
464 computer via the USB cable, or through the radio
465 link. TeleMini doesn't provide a USB connector and so it is
466 always communicated with over radio. Select the appropriate
467 TeleDongle device when the list of devices is presented and
468 AltosUI will interact with an altimeter over the radio link.
471 One oddity in the current interface is how AltosUI selects the
472 frequency for radio communications. Instead of providing
473 an interface to specifically configure the frequency, it uses
474 whatever frequency was most recently selected for the target
475 TeleDongle device in Monitor Flight mode. If you haven't ever
476 used that mode with the TeleDongle in question, select the
477 Monitor Flight button from the top level UI, and pick the
478 appropriate TeleDongle device. Once the flight monitoring
479 window is open, select the desired frequency and then close it
480 down again. All radio communications will now use that frequency.
485 Save Flight Data—Recover flight data from the rocket without
491 Configure altimeter apogee delays or main deploy heights
492 to respond to changing launch conditions. You can also
493 'reboot' the altimeter. Use this to remotely enable the
494 flight computer by turning TeleMetrum on in "idle" mode,
495 then once the air-frame is oriented for launch, you can
496 reboot the altimeter and have it restart in pad mode
497 without having to climb the scary ladder.
502 Fire Igniters—Test your deployment charges without snaking
503 wires out through holes in the air-frame. Simply assembly the
504 rocket as if for flight with the apogee and main charges
505 loaded, then remotely command the altimeter to fire the
511 Operation over the radio link for configuring an altimeter, ground
512 testing igniters, and so forth uses the same RF frequencies as flight
513 telemetry. To configure the desired TeleDongle frequency, select
514 the monitor flight tab, then use the frequency selector and
515 close the window before performing other desired radio operations.
518 TeleMetrum only enables radio commanding in 'idle' mode, so
519 make sure you have TeleMetrum lying horizontally when you turn
520 it on. Otherwise, TeleMetrum will start in 'pad' mode ready for
521 flight, and will not be listening for command packets from TeleDongle.
524 TeleMini listens for a command packet for five seconds after
525 first being turned on, if it doesn't hear anything, it enters
526 'pad' mode, ready for flight and will no longer listen for
527 command packets. The easiest way to connect to TeleMini is to
528 initiate the command and select the TeleDongle device. At this
529 point, the TeleDongle will be attempting to communicate with
530 the TeleMini. Now turn TeleMini on, and it should immediately
531 start communicating with the TeleDongle and the desired
532 operation can be performed.
535 You can monitor the operation of the radio link by watching the
536 lights on the devices. The red LED will flash each time a packet
537 is transmitted, while the green LED will light up on TeleDongle when
538 it is waiting to receive a packet from the altimeter.
542 <title>Ground Testing </title>
544 An important aspect of preparing a rocket using electronic deployment
545 for flight is ground testing the recovery system. Thanks
546 to the bi-directional radio link central to the Altus Metrum system,
547 this can be accomplished in a TeleMetrum or TeleMini equipped rocket
548 with less work than you may be accustomed to with other systems. It
552 Just prep the rocket for flight, then power up the altimeter
553 in "idle" mode (placing air-frame horizontal for TeleMetrum or
554 selected the Configure Altimeter tab for TeleMini). This will cause
555 the firmware to go into "idle" mode, in which the normal flight
556 state machine is disabled and charges will not fire without
557 manual command. You can now command the altimeter to fire the apogee
558 or main charges from a safe distance using your computer and
559 TeleDongle and the Fire Igniter tab to complete ejection testing.
563 <title>Radio Link </title>
565 The chip our boards are based on incorporates an RF transceiver, but
566 it's not a full duplex system... each end can only be transmitting or
567 receiving at any given moment. So we had to decide how to manage the
571 By design, the altimeter firmware listens for the radio link when
572 it's in "idle mode", which
573 allows us to use the radio link to configure the rocket, do things like
574 ejection tests, and extract data after a flight without having to
575 crack open the air-frame. However, when the board is in "flight
576 mode", the altimeter only
577 transmits and doesn't listen at all. That's because we want to put
578 ultimate priority on event detection and getting telemetry out of
580 the radio in case the rocket crashes and we aren't able to extract
584 We don't use a 'normal packet radio' mode like APRS because they're
585 just too inefficient. The GFSK modulation we use is FSK with the
586 base-band pulses passed through a
587 Gaussian filter before they go into the modulator to limit the
588 transmitted bandwidth. When combined with the hardware forward error
589 correction support in the cc1111 chip, this allows us to have a very
590 robust 38.4 kilobit data link with only 10 milliwatts of transmit
591 power, a whip antenna in the rocket, and a hand-held Yagi on the
592 ground. We've had flights to above 21k feet AGL with great reception,
593 and calculations suggest we should be good to well over 40k feet AGL
594 with a 5-element yagi on the ground. We hope to fly boards to higher
595 altitudes over time, and would of course appreciate customer feedback
596 on performance in higher altitude flights!
600 <title>Configurable Parameters</title>
602 Configuring an Altus Metrum altimeter for flight is very
603 simple. Even on our baro-only TeleMini board, the use of a Kalman
604 filter means there is no need to set a "mach delay". The few
605 configurable parameters can all be set using AltosUI over USB or
606 or radio link via TeleDongle.
609 <title>Radio Frequency</title>
611 Altus Metrum boards support radio frequencies in the 70cm
612 band. By default, the configuration interface provides a
613 list of 10 "standard" frequencies in 100kHz channels starting at
614 434.550MHz. However, the firmware supports use of
615 any 50kHz multiple within the 70cm band. At any given
616 launch, we highly recommend coordinating when and by whom each
617 frequency will be used to avoid interference. And of course, both
618 altimeter and TeleDongle must be configured to the same
619 frequency to successfully communicate with each other.
623 <title>Apogee Delay</title>
625 Apogee delay is the number of seconds after the altimeter detects flight
626 apogee that the drogue charge should be fired. In most cases, this
627 should be left at the default of 0. However, if you are flying
628 redundant electronics such as for an L3 certification, you may wish
629 to set one of your altimeters to a positive delay so that both
630 primary and backup pyrotechnic charges do not fire simultaneously.
633 The Altus Metrum apogee detection algorithm fires exactly at
634 apogee. If you are also flying an altimeter like the
635 PerfectFlite MAWD, which only supports selecting 0 or 1
636 seconds of apogee delay, you may wish to set the MAWD to 0
637 seconds delay and set the TeleMetrum to fire your backup 2
638 or 3 seconds later to avoid any chance of both charges
639 firing simultaneously. We've flown several air-frames this
640 way quite happily, including Keith's successful L3 cert.
644 <title>Main Deployment Altitude</title>
646 By default, the altimeter will fire the main deployment charge at an
647 elevation of 250 meters (about 820 feet) above ground. We think this
648 is a good elevation for most air-frames, but feel free to change this
649 to suit. In particular, if you are flying two altimeters, you may
651 deployment elevation for the backup altimeter to be something lower
652 than the primary so that both pyrotechnic charges don't fire
657 <title>Maximum Flight Log</title>
659 TeleMetrum version 1.1 and 1.2 have 2MB of on-board flash storage,
660 enough to hold over 40 minutes of data at full data rate
661 (100 samples/second). TeleMetrum 1.0 has 1MB of on-board
662 storage. As data are stored at a reduced rate during descent
663 (10 samples/second), there's plenty of space to store many
664 flights worth of data.
667 The on-board flash is partitioned into separate flight logs,
668 each of a fixed maximum size. Increase the maximum size of
669 each log and you reduce the number of flights that can be
670 stored. Decrease the size and TeleMetrum can store more
674 All of the configuration data is also stored in the flash
675 memory, which consumes 64kB on TeleMetrum v1.1/v1.2 and 256B on
676 TeleMetrum v1.0. This configuration space is not available
677 for storing flight log data.
680 To compute the amount of space needed for a single flight,
681 you can multiply the expected ascent time (in seconds) by
682 800, multiply the expected descent time (in seconds) by 80
683 and add the two together. That will slightly under-estimate
684 the storage (in bytes) needed for the flight. For instance,
685 a flight spending 20 seconds in ascent and 150 seconds in
686 descent will take about (20 * 800) + (150 * 80) = 28000
687 bytes of storage. You could store dozens of these flights in
691 The default size, 192kB, allows for 10 flights of storage on
692 TeleMetrum v1.1/v1.2 and 5 flights on TeleMetrum v1.0. This
693 ensures that you won't need to erase the memory before
694 flying each time while still allowing more than sufficient
695 storage for each flight.
698 As TeleMini does not contain an accelerometer, it stores
699 data at 10 samples per second during ascent and one sample
700 per second during descent. Each sample is a two byte reading
701 from the barometer. These are stored in 5kB of
702 on-chip flash memory which can hold 256 seconds at the
703 ascent rate or 2560 seconds at the descent rate. Because of
704 the limited storage, TeleMini cannot hold data for more than
705 one flight, and so must be erased after each flight or it
706 will not capture data for subsequent flights.
710 <title>Ignite Mode</title>
712 Instead of firing one charge at apogee and another charge at
713 a fixed height above the ground, you can configure the
714 altimeter to fire both at apogee or both during
715 descent. This was added to support an airframe that has two
716 TeleMetrum computers, one in the fin can and one in the
720 Providing the ability to use both igniters for apogee or
721 main allows some level of redundancy without needing two
722 flight computers. In Redundant Apogee or Redundant Main
723 mode, the two charges will be fired two seconds apart.
727 <title>Pad Orientation</title>
729 TeleMetrum measures acceleration along the axis of the
730 board. Which way the board is oriented affects the sign of
731 the acceleration value. Instead of trying to guess which way
732 the board is mounted in the air frame, TeleMetrum must be
733 explicitly configured for either Antenna Up or Antenna
734 Down. The default, Antenna Up, expects the end of the
735 TeleMetrum board connected to the 70cm antenna to be nearest
736 the nose of the rocket, with the end containing the screw
737 terminals nearest the tail.
745 <title>AltosUI</title>
747 The AltosUI program provides a graphical user interface for
748 interacting with the Altus Metrum product family, including
749 TeleMetrum, TeleMini and TeleDongle. AltosUI can monitor telemetry data,
750 configure TeleMetrum, TeleMini and TeleDongle devices and many other
751 tasks. The primary interface window provides a selection of
752 buttons, one for each major activity in the system. This manual
753 is split into chapters, each of which documents one of the tasks
754 provided from the top-level toolbar.
757 <title>Monitor Flight</title>
758 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
760 Selecting this item brings up a dialog box listing all of the
761 connected TeleDongle devices. When you choose one of these,
762 AltosUI will create a window to display telemetry data as
763 received by the selected TeleDongle device.
766 All telemetry data received are automatically recorded in
767 suitable log files. The name of the files includes the current
768 date and rocket serial and flight numbers.
771 The radio frequency being monitored by the TeleDongle device is
772 displayed at the top of the window. You can configure the
773 frequency by clicking on the frequency box and selecting the desired
774 frequency. AltosUI remembers the last frequency selected for each
775 TeleDongle and selects that automatically the next time you use
779 Below the TeleDongle frequency selector, the window contains a few
780 significant pieces of information about the altimeter providing
781 the telemetry data stream:
785 <para>The configured call-sign</para>
788 <para>The device serial number</para>
791 <para>The flight number. Each altimeter remembers how many
797 The rocket flight state. Each flight passes through several
798 states including Pad, Boost, Fast, Coast, Drogue, Main and
804 The Received Signal Strength Indicator value. This lets
805 you know how strong a signal TeleDongle is receiving. The
806 radio inside TeleDongle operates down to about -99dBm;
807 weaker signals may not be receivable. The packet link uses
808 error detection and correction techniques which prevent
809 incorrect data from being reported.
814 The age of the displayed data, in seconds since the last
815 successfully received telemetry packet. In normal operation
816 this will stay in the low single digits. If the number starts
817 counting up, then you are no longer receiving data over the radio
818 link from the flight computer.
823 Finally, the largest portion of the window contains a set of
824 tabs, each of which contain some information about the rocket.
825 They're arranged in 'flight order' so that as the flight
826 progresses, the selected tab automatically switches to display
827 data relevant to the current state of the flight. You can select
828 other tabs at any time. The final 'table' tab displays all of
829 the raw telemetry values in one place in a spreadsheet-like format.
832 <title>Launch Pad</title>
834 The 'Launch Pad' tab shows information used to decide when the
835 rocket is ready for flight. The first elements include red/green
836 indicators, if any of these is red, you'll want to evaluate
837 whether the rocket is ready to launch:
841 Battery Voltage. This indicates whether the Li-Po battery
842 powering the TeleMetrum has sufficient charge to last for
843 the duration of the flight. A value of more than
844 3.7V is required for a 'GO' status.
849 Apogee Igniter Voltage. This indicates whether the apogee
850 igniter has continuity. If the igniter has a low
851 resistance, then the voltage measured here will be close
852 to the Li-Po battery voltage. A value greater than 3.2V is
853 required for a 'GO' status.
858 Main Igniter Voltage. This indicates whether the main
859 igniter has continuity. If the igniter has a low
860 resistance, then the voltage measured here will be close
861 to the Li-Po battery voltage. A value greater than 3.2V is
862 required for a 'GO' status.
867 On-board Data Logging. This indicates whether there is
868 space remaining on-board to store flight data for the
869 upcoming flight. If you've downloaded data, but failed
870 to erase flights, there may not be any space
871 left. TeleMetrum can store multiple flights, depending
872 on the configured maximum flight log size. TeleMini
873 stores only a single flight, so it will need to be
874 downloaded and erased after each flight to capture
875 data. This only affects on-board flight logging; the
876 altimeter will still transmit telemetry and fire
877 ejection charges at the proper times.
882 GPS Locked. For a TeleMetrum device, this indicates whether the GPS receiver is
883 currently able to compute position information. GPS requires
884 at least 4 satellites to compute an accurate position.
889 GPS Ready. For a TeleMetrum device, this indicates whether GPS has reported at least
890 10 consecutive positions without losing lock. This ensures
891 that the GPS receiver has reliable reception from the
897 The Launchpad tab also shows the computed launch pad position
898 and altitude, averaging many reported positions to improve the
904 <title>Ascent</title>
906 This tab is shown during Boost, Fast and Coast
907 phases. The information displayed here helps monitor the
908 rocket as it heads towards apogee.
911 The height, speed and acceleration are shown along with the
912 maximum values for each of them. This allows you to quickly
913 answer the most commonly asked questions you'll hear during
917 The current latitude and longitude reported by the TeleMetrum GPS are
918 also shown. Note that under high acceleration, these values
919 may not get updated as the GPS receiver loses position
920 fix. Once the rocket starts coasting, the receiver should
921 start reporting position again.
924 Finally, the current igniter voltages are reported as in the
925 Launch Pad tab. This can help diagnose deployment failures
926 caused by wiring which comes loose under high acceleration.
930 <title>Descent</title>
932 Once the rocket has reached apogee and (we hope) activated the
933 apogee charge, attention switches to tracking the rocket on
934 the way back to the ground, and for dual-deploy flights,
935 waiting for the main charge to fire.
938 To monitor whether the apogee charge operated correctly, the
939 current descent rate is reported along with the current
940 height. Good descent rates vary based on the choice of recovery
941 components, but generally range from 15-30m/s on drogue and should
942 be below 10m/s when under the main parachute in a dual-deploy flight.
945 For TeleMetrum altimeters, you can locate the rocket in the
946 sky using the elevation and bearing information to figure
947 out where to look. Elevation is in degrees above the
948 horizon. Bearing is reported in degrees relative to true
949 north. Range can help figure out how big the rocket will
950 appear. Ground Distance shows how far it is to a point
951 directly under the rocket and can help figure out where the
952 rocket is likely to land. Note that all of these values are
953 relative to the pad location. If the elevation is near 90°,
954 the rocket is over the pad, not over you.
957 Finally, the igniter voltages are reported in this tab as
958 well, both to monitor the main charge as well as to see what
959 the status of the apogee charge is. Note that some commercial
960 e-matches are designed to retain continuity even after being
961 fired, and will continue to show as green or return from red to
966 <title>Landed</title>
968 Once the rocket is on the ground, attention switches to
969 recovery. While the radio signal is often lost once the
970 rocket is on the ground, the last reported GPS position is
971 generally within a short distance of the actual landing location.
974 The last reported GPS position is reported both by
975 latitude and longitude as well as a bearing and distance from
976 the launch pad. The distance should give you a good idea of
977 whether to walk or hitch a ride. Take the reported
978 latitude and longitude and enter them into your hand-held GPS
979 unit and have that compute a track to the landing location.
982 Both TeleMini and TeleMetrum will continue to transmit RDF
983 tones after landing, allowing you to locate the rocket by
984 following the radio signal if necessary. You may need to get
985 away from the clutter of the flight line, or even get up on
986 a hill (or your neighbor's RV roof) to receive the RDF signal.
989 The maximum height, speed and acceleration reported
990 during the flight are displayed for your admiring observers.
991 The accuracy of these immediate values depends on the quality
992 of your radio link and how many packets were received.
993 Recovering the on-board data after flight will likely yield
994 more precise results.
997 To get more detailed information about the flight, you can
998 click on the 'Graph Flight' button which will bring up a
999 graph window for the current flight.
1003 <title>Site Map</title>
1005 When the TeleMetrum has a GPS fix, the Site Map tab will map
1006 the rocket's position to make it easier for you to locate the
1007 rocket, both while it is in the air, and when it has landed. The
1008 rocket's state is indicated by color: white for pad, red for
1009 boost, pink for fast, yellow for coast, light blue for drogue,
1010 dark blue for main, and black for landed.
1013 The map's scale is approximately 3m (10ft) per pixel. The map
1014 can be dragged using the left mouse button. The map will attempt
1015 to keep the rocket roughly centered while data is being received.
1018 Images are fetched automatically via the Google Maps Static API,
1019 and cached on disk for reuse. If map images cannot be downloaded,
1020 the rocket's path will be traced on a dark gray background
1024 You can pre-load images for your favorite launch sites
1025 before you leave home; check out the 'Preload Maps' section below.
1030 <title>Save Flight Data</title>
1032 The altimeter records flight data to its internal flash memory.
1033 TeleMetrum data is recorded at a much higher rate than the telemetry
1034 system can handle, and is not subject to radio drop-outs. As
1035 such, it provides a more complete and precise record of the
1036 flight. The 'Save Flight Data' button allows you to read the
1037 flash memory and write it to disk. As TeleMini has only a barometer, it
1038 records data at the same rate as the telemetry signal, but there will be
1039 no data lost due to telemetry drop-outs.
1042 Clicking on the 'Save Flight Data' button brings up a list of
1043 connected TeleMetrum and TeleDongle devices. If you select a
1044 TeleMetrum device, the flight data will be downloaded from that
1045 device directly. If you select a TeleDongle device, flight data
1046 will be downloaded from an altimeter over radio link via the
1047 specified TeleDongle. See the chapter on Controlling An Altimeter
1048 Over The Radio Link for more information.
1051 After the device has been selected, a dialog showing the
1052 flight data saved in the device will be shown allowing you to
1053 select which flights to download and which to delete. With
1054 version 0.9 or newer firmware, you must erase flights in order
1055 for the space they consume to be reused by another
1056 flight. This prevents accidentally losing flight data
1057 if you neglect to download data before flying again. Note that
1058 if there is no more space available in the device, then no
1059 data will be recorded during the next flight.
1062 The file name for each flight log is computed automatically
1063 from the recorded flight date, altimeter serial number and
1064 flight number information.
1068 <title>Replay Flight</title>
1070 Select this button and you are prompted to select a flight
1071 record file, either a .telem file recording telemetry data or a
1072 .eeprom file containing flight data saved from the altimeter
1076 Once a flight record is selected, the flight monitor interface
1077 is displayed and the flight is re-enacted in real time. Check
1078 the Monitor Flight chapter above to learn how this window operates.
1082 <title>Graph Data</title>
1084 Select this button and you are prompted to select a flight
1085 record file, either a .telem file recording telemetry data or a
1086 .eeprom file containing flight data saved from
1090 Once a flight record is selected, a window with two tabs is
1091 opened. The first tab contains a graph with acceleration
1092 (blue), velocity (green) and altitude (red) of the flight,
1093 measured in metric units. The
1094 apogee(yellow) and main(magenta) igniter voltages are also
1095 displayed; high voltages indicate continuity, low voltages
1096 indicate open circuits. The second tab contains some basic
1100 The graph can be zoomed into a particular area by clicking and
1101 dragging down and to the right. Once zoomed, the graph can be
1102 reset by clicking and dragging up and to the left. Holding down
1103 control and clicking and dragging allows the graph to be panned.
1104 The right mouse button causes a pop-up menu to be displayed, giving
1105 you the option save or print the plot.
1108 Note that telemetry files will generally produce poor graphs
1109 due to the lower sampling rate and missed telemetry packets.
1110 Use saved flight data in .eeprom files for graphing where possible.
1114 <title>Export Data</title>
1116 This tool takes the raw data files and makes them available for
1117 external analysis. When you select this button, you are prompted to
1119 data file (either .eeprom or .telem will do, remember that
1120 .eeprom files contain higher resolution and more continuous
1121 data). Next, a second dialog appears which is used to select
1122 where to write the resulting file. It has a selector to choose
1123 between CSV and KML file formats.
1126 <title>Comma Separated Value Format</title>
1128 This is a text file containing the data in a form suitable for
1129 import into a spreadsheet or other external data analysis
1130 tool. The first few lines of the file contain the version and
1131 configuration information from the altimeter, then
1132 there is a single header line which labels all of the
1133 fields. All of these lines start with a '#' character which
1134 many tools can be configured to skip over.
1137 The remaining lines of the file contain the data, with each
1138 field separated by a comma and at least one space. All of
1139 the sensor values are converted to standard units, with the
1140 barometric data reported in both pressure, altitude and
1141 height above pad units.
1145 <title>Keyhole Markup Language (for Google Earth)</title>
1147 This is the format used by Google Earth to provide an overlay
1148 within that application. With this, you can use Google Earth to
1149 see the whole flight path in 3D.
1154 <title>Configure Altimeter</title>
1156 Select this button and then select either a TeleMetrum or
1157 TeleDongle Device from the list provided. Selecting a TeleDongle
1158 device will use the radio link to configure a remote altimeter.
1161 The first few lines of the dialog provide information about the
1162 connected device, including the product name,
1163 software version and hardware serial number. Below that are the
1164 individual configuration entries.
1167 At the bottom of the dialog, there are four buttons:
1172 Save. This writes any changes to the
1173 configuration parameter block in flash memory. If you don't
1174 press this button, any changes you make will be lost.
1179 Reset. This resets the dialog to the most recently saved values,
1180 erasing any changes you have made.
1185 Reboot. This reboots the device. Use this to
1186 switch from idle to pad mode by rebooting once the rocket is
1187 oriented for flight, or to confirm changes you think you saved
1193 Close. This closes the dialog. Any unsaved changes will be
1199 The rest of the dialog contains the parameters to be configured.
1202 <title>Main Deploy Altitude</title>
1204 This sets the altitude (above the recorded pad altitude) at
1205 which the 'main' igniter will fire. The drop-down menu shows
1206 some common values, but you can edit the text directly and
1207 choose whatever you like. If the apogee charge fires below
1208 this altitude, then the main charge will fire two seconds
1209 after the apogee charge fires.
1213 <title>Apogee Delay</title>
1215 When flying redundant electronics, it's often important to
1216 ensure that multiple apogee charges don't fire at precisely
1217 the same time, as that can over pressurize the apogee deployment
1218 bay and cause a structural failure of the air-frame. The Apogee
1219 Delay parameter tells the flight computer to fire the apogee
1220 charge a certain number of seconds after apogee has been
1225 <title>Radio Frequency</title>
1227 This configures which of the configured frequencies to use for both
1228 telemetry and packet command mode. Note that if you set this
1229 value via packet command mode, you will have to reconfigure
1230 the TeleDongle frequency before you will be able to use packet
1235 <title>Radio Calibration</title>
1237 The radios in every Altus Metrum device are calibrated at the
1238 factory to ensure that they transmit and receive on the
1239 specified frequency. If you need to you can adjust the calibration
1240 by changing this value. Do not do this without understanding what
1241 the value means, read the appendix on calibration and/or the source
1242 code for more information. To change a TeleDongle's calibration,
1243 you must reprogram the unit completely.
1247 <title>Callsign</title>
1249 This sets the call sign included in each telemetry packet. Set this
1250 as needed to conform to your local radio regulations.
1254 <title>Maximum Flight Log Size</title>
1256 This sets the space (in kilobytes) allocated for each flight
1257 log. The available space will be divided into chunks of this
1258 size. A smaller value will allow more flights to be stored,
1259 a larger value will record data from longer flights.
1263 <title>Ignite Mode</title>
1265 TeleMetrum and TeleMini provide two igniter channels as they
1266 were originally designed as dual-deploy flight
1267 computers. This configuration parameter allows the two
1268 channels to be used in different configurations.
1273 Dual Deploy. This is the usual mode of operation; the
1274 'apogee' channel is fired at apogee and the 'main'
1275 channel at the height above ground specified by the
1276 'Main Deploy Altitude' during descent.
1281 Redundant Apogee. This fires both channels at
1282 apogee, the 'apogee' channel first followed after a two second
1283 delay by the 'main' channel.
1288 Redundant Main. This fires both channels at the
1289 height above ground specified by the Main Deploy
1290 Altitude setting during descent. The 'apogee'
1291 channel is fired first, followed after a two second
1292 delay by the 'main' channel.
1298 <title>Pad Orientation</title>
1300 Because it includes an accelerometer, TeleMetrum is
1301 sensitive to the orientation of the board. By default, it
1302 expects the antenna end to point forward. This parameter
1303 allows that default to be changed, permitting the board to
1304 be mounted with the antenna pointing aft instead.
1309 Antenna Up. In this mode, the antenna end of the
1310 TeleMetrum board must point forward, in line with the
1311 expected flight path.
1316 Antenna Down. In this mode, the antenna end of the
1317 TeleMetrum board must point aft, in line with the
1318 expected flight path.
1325 <title>Configure AltosUI</title>
1327 This button presents a dialog so that you can configure the AltosUI global settings.
1330 <title>Voice Settings</title>
1332 AltosUI provides voice announcements during flight so that you
1333 can keep your eyes on the sky and still get information about
1334 the current flight status. However, sometimes you don't want
1339 <para>Enable—turns all voice announcements on and off</para>
1343 Test Voice—Plays a short message allowing you to verify
1344 that the audio system is working and the volume settings
1351 <title>Log Directory</title>
1353 AltosUI logs all telemetry data and saves all TeleMetrum flash
1354 data to this directory. This directory is also used as the
1355 staring point when selecting data files for display or export.
1358 Click on the directory name to bring up a directory choosing
1359 dialog, select a new directory and click 'Select Directory' to
1360 change where AltosUI reads and writes data files.
1364 <title>Callsign</title>
1366 This value is transmitted in each command packet sent from
1367 TeleDongle and received from an altimeter. It is not used in
1368 telemetry mode, as the callsign configured in the altimeter board
1369 is included in all telemetry packets. Configure this
1370 with the AltosUI operators call sign as needed to comply with
1371 your local radio regulations.
1375 <title>Imperial Units</title>
1377 This switches between metric units (meters) and imperial
1378 units (feet and miles). This affects the display of values
1379 use during flight monitoring, data graphing and all of the
1380 voice announcements. It does not change the units used when
1381 exporting to CSV files, those are always produced in metric units.
1385 <title>Font Size</title>
1387 Selects the set of fonts used in the flight monitor
1388 window. Choose between the small, medium and large sets.
1392 <title>Serial Debug</title>
1394 This causes all communication with a connected device to be
1395 dumped to the console from which AltosUI was started. If
1396 you've started it from an icon or menu entry, the output
1397 will simply be discarded. This mode can be useful to debug
1398 various serial communication issues.
1402 <title>Manage Frequencies</title>
1404 This brings up a dialog where you can configure the set of
1405 frequencies shown in the various frequency menus. You can
1406 add as many as you like, or even reconfigure the default
1407 set. Changing this list does not affect the frequency
1408 settings of any devices, it only changes the set of
1409 frequencies shown in the menus.
1414 <title>Configure Groundstation</title>
1416 Select this button and then select a TeleDongle Device from the list provided.
1419 The first few lines of the dialog provide information about the
1420 connected device, including the product name,
1421 software version and hardware serial number. Below that are the
1422 individual configuration entries.
1425 Note that the TeleDongle itself doesn't save any configuration
1426 data, the settings here are recorded on the local machine in
1427 the Java preferences database. Moving the TeleDongle to
1428 another machine, or using a different user account on the same
1429 machine will cause settings made here to have no effect.
1432 At the bottom of the dialog, there are three buttons:
1437 Save. This writes any changes to the
1438 local Java preferences file. If you don't
1439 press this button, any changes you make will be lost.
1444 Reset. This resets the dialog to the most recently saved values,
1445 erasing any changes you have made.
1450 Close. This closes the dialog. Any unsaved changes will be
1456 The rest of the dialog contains the parameters to be configured.
1459 <title>Frequency</title>
1461 This configures the frequency to use for both telemetry and
1462 packet command mode. Set this before starting any operation
1463 involving packet command mode so that it will use the right
1464 frequency. Telemetry monitoring mode also provides a menu to
1465 change the frequency, and that menu also sets the same Java
1466 preference value used here.
1470 <title>Radio Calibration</title>
1472 The radios in every Altus Metrum device are calibrated at the
1473 factory to ensure that they transmit and receive on the
1474 specified frequency. To change a TeleDongle's calibration,
1475 you must reprogram the unit completely, so this entry simply
1476 shows the current value and doesn't allow any changes.
1481 <title>Flash Image</title>
1483 This reprograms any Altus Metrum device by using a TeleMetrum
1484 or TeleDongle as a programming dongle. Please read the
1485 directions for flashing devices in the Updating Device
1486 Firmware chapter below.
1489 Once you have the programmer and target devices connected,
1490 push the 'Flash Image' button. That will present a dialog box
1491 listing all of the connected devices. Carefully select the
1492 programmer device, not the device to be programmed.
1495 Next, select the image to flash to the device. These are named
1496 with the product name and firmware version. The file selector
1497 will start in the directory containing the firmware included
1498 with the AltosUI package. Navigate to the directory containing
1499 the desired firmware if it isn't there.
1502 Next, a small dialog containing the device serial number and
1503 RF calibration values should appear. If these values are
1504 incorrect (possibly due to a corrupted image in the device),
1505 enter the correct values here.
1508 Finally, a dialog containing a progress bar will follow the
1509 programming process.
1512 When programming is complete, the target device will
1513 reboot. Note that if the target device is connected via USB, you
1514 will have to unplug it and then plug it back in for the USB
1515 connection to reset so that you can communicate with the device
1520 <title>Fire Igniter</title>
1522 This activates the igniter circuits in TeleMetrum to help test
1523 recovery systems deployment. Because this command can operate
1524 over the Packet Command Link, you can prepare the rocket as
1525 for flight and then test the recovery system without needing
1526 to snake wires inside the air-frame.
1529 Selecting the 'Fire Igniter' button brings up the usual device
1530 selection dialog. Pick the desired TeleDongle or TeleMetrum
1531 device. This brings up another window which shows the current
1532 continuity test status for both apogee and main charges.
1535 Next, select the desired igniter to fire. This will enable the
1539 Select the 'Arm' button. This enables the 'Fire' button. The
1540 word 'Arm' is replaced by a countdown timer indicating that
1541 you have 10 seconds to press the 'Fire' button or the system
1542 will deactivate, at which point you start over again at
1543 selecting the desired igniter.
1547 <title>Scan Channels</title>
1549 This listens for telemetry packets on all of the configured
1550 frequencies, displaying information about each device it
1551 receives a packet from. You can select which of the three
1552 telemetry formats should be tried; by default, it only listens
1553 for the standard telemetry packets used in v1.0 and later
1558 <title>Load Maps</title>
1560 Before heading out to a new launch site, you can use this to
1561 load satellite images in case you don't have internet
1562 connectivity at the site. This loads a fairly large area
1563 around the launch site, which should cover any flight you're likely to make.
1566 There's a drop-down menu of launch sites we know about; if
1567 your favorites aren't there, please let us know the lat/lon
1568 and name of the site. The contents of this list are actually
1569 downloaded at run-time, so as new sites are sent in, they'll
1570 get automatically added to this list.
1573 If the launch site isn't in the list, you can manually enter the lat/lon values
1576 Clicking the 'Load Map' button will fetch images from Google
1577 Maps; note that Google limits how many images you can fetch at
1578 once, so if you load more than one launch site, you may get
1579 some gray areas in the map which indicate that Google is tired
1580 of sending data to you. Try again later.
1584 <title>Monitor Idle</title>
1586 This brings up a dialog similar to the Monitor Flight UI,
1587 except it works with the altimeter in "idle" mode by sending
1588 query commands to discover the current state rather than
1589 listening for telemetry packets.
1594 <title>AltosDroid</title>
1596 AltosDroid provides the same flight monitoring capabilities as
1597 AltosUI, but runs on Android devices and is designed to connect
1598 to a TeleBT receiver over Bluetooth™. Altos Droid monitors
1599 telemetry data, logging it to internal storage in the Android
1600 device, and presents that data in a UI the same way the 'Monitor
1601 Flight' window does in AltosUI.
1604 This manual will explain how to configure AltosDroid, connect
1605 to TeleBT, operate the flight monitoring interface and describe
1606 what the displayed data means.
1609 <title>Installing AltosDroid</title>
1611 AltosDroid is included in the Google Play store. To install
1612 it on your Android device, open open the Google Play Store
1613 application and search for "altosdroid". Make sure you don't
1614 have a space between "altos" and "droid" or you probably won't
1615 find what you want. That should bring you to the right page
1616 from which you can download and install the application.
1620 <title>Connecting to TeleBT</title>
1623 <title>Configuring AltosDroid</title>
1626 <title>Flight Monitoring</title>
1629 <title>Downloading Flight Logs</title>
1633 <title>Using Altus Metrum Products</title>
1635 <title>Being Legal</title>
1637 First off, in the US, you need an <ulink url="http://www.altusmetrum.org/Radio/">amateur radio license</ulink> or
1638 other authorization to legally operate the radio transmitters that are part
1643 <title>In the Rocket</title>
1645 In the rocket itself, you just need a <ulink url="http://www.altusmetrum.org/TeleMetrum/">TeleMetrum</ulink> or
1646 <ulink url="http://www.altusmetrum.org/TeleMini/">TeleMini</ulink> board and
1647 a single-cell, 3.7 volt nominal Li-Po rechargeable battery. An
1648 850mAh battery weighs less than a 9V alkaline battery, and will
1649 run a TeleMetrum for hours.
1650 A 110mAh battery weighs less than a triple A battery and will run a TeleMetrum for
1651 a few hours, or a TeleMini for much (much) longer.
1654 By default, we ship the altimeters with a simple wire antenna. If your
1655 electronics bay or the air-frame it resides within is made of carbon fiber,
1656 which is opaque to RF signals, you may choose to have an SMA connector
1657 installed so that you can run a coaxial cable to an antenna mounted
1658 elsewhere in the rocket.
1662 <title>On the Ground</title>
1664 To receive the data stream from the rocket, you need an antenna and short
1665 feed-line connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. If possible, use an SMA to BNC
1666 adapter instead of feedline between the antenna feedpoint and
1667 TeleDongle, as this will give you the best performance. The
1668 TeleDongle in turn plugs directly into the USB port on a notebook
1669 computer. Because TeleDongle looks like a simple serial port, your computer
1670 does not require special device drivers... just plug it in.
1673 The GUI tool, AltosUI, is written in Java and runs across
1674 Linux, Mac OS and Windows. There's also a suite of C tools
1675 for Linux which can perform most of the same tasks.
1678 After the flight, you can use the radio link to extract the more detailed data
1679 logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
1680 TeleMetrum board directly. Pulling out the data without having to open up
1681 the rocket is pretty cool! A USB cable is also how you charge the Li-Po
1682 battery, so you'll want one of those anyway... the same cable used by lots
1683 of digital cameras and other modern electronic stuff will work fine.
1686 If your TeleMetrum-equipped rocket lands out of sight, you may enjoy having a hand-held GPS
1687 receiver, so that you can put in a way-point for the last reported rocket
1688 position before touch-down. This makes looking for your rocket a lot like
1689 Geo-Caching... just go to the way-point and look around starting from there.
1692 You may also enjoy having a ham radio "HT" that covers the 70cm band... you
1693 can use that with your antenna to direction-find the rocket on the ground
1694 the same way you can use a Walston or Beeline tracker. This can be handy
1695 if the rocket is hiding in sage brush or a tree, or if the last GPS position
1696 doesn't get you close enough because the rocket dropped into a canyon, or
1697 the wind is blowing it across a dry lake bed, or something like that... Keith
1698 and Bdale both currently own and use the Yaesu VX-7R at launches.
1701 So, to recap, on the ground the hardware you'll need includes:
1702 <orderedlist inheritnum='inherit' numeration='arabic'>
1704 an antenna and feed-line or adapter
1713 optionally, a hand-held GPS receiver
1716 optionally, an HT or receiver covering 435 MHz
1721 The best hand-held commercial directional antennas we've found for radio
1722 direction finding rockets are from
1723 <ulink url="http://www.arrowantennas.com/" >
1726 The 440-3 and 440-5 are both good choices for finding a
1727 TeleMetrum- or TeleMini- equipped rocket when used with a suitable
1728 70cm HT. TeleDongle and an SMA to BNC adapter fit perfectly
1729 between the driven element and reflector of Arrow antennas.
1733 <title>Data Analysis</title>
1735 Our software makes it easy to log the data from each flight, both the
1736 telemetry received during the flight itself, and the more
1737 complete data log recorded in the flash memory on the altimeter
1738 board. Once this data is on your computer, our post-flight tools make it
1739 easy to quickly get to the numbers everyone wants, like apogee altitude,
1740 max acceleration, and max velocity. You can also generate and view a
1741 standard set of plots showing the altitude, acceleration, and
1742 velocity of the rocket during flight. And you can even export a TeleMetrum data file
1743 usable with Google Maps and Google Earth for visualizing the flight path
1744 in two or three dimensions!
1747 Our ultimate goal is to emit a set of files for each flight that can be
1748 published as a web page per flight, or just viewed on your local disk with
1753 <title>Future Plans</title>
1755 In the future, we intend to offer "companion boards" for the rocket
1756 that will plug in to TeleMetrum to collect additional data, provide
1757 more pyro channels, and so forth.
1760 Also under design is a new flight computer with more sensors, more
1761 pyro channels, and a more powerful radio system designed for use
1762 in multi-stage, complex, and extreme altitude projects.
1765 We are also working on alternatives to TeleDongle. One is a
1766 a stand-alone, hand-held ground terminal that will allow monitoring
1767 the rocket's status, collecting data during flight, and logging data
1768 after flight without the need for a notebook computer on the
1769 flight line. Particularly since it is so difficult to read most
1770 notebook screens in direct sunlight, we think this will be a great
1771 thing to have. We are also working on a TeleDongle variant with
1772 Bluetooth that will work with Android phones and tablets.
1775 Because all of our work is open, both the hardware designs and the
1776 software, if you have some great idea for an addition to the current
1777 Altus Metrum family, feel free to dive in and help! Or let us know
1778 what you'd like to see that we aren't already working on, and maybe
1779 we'll get excited about it too...
1783 <ulink url="http://altusmetrum.org/">web site</ulink> for more news
1784 and information as our family of products evolves!
1789 <title>Altimeter Installation Recommendations</title>
1791 Building high-power rockets that fly safely is hard enough. Mix
1792 in some sophisticated electronics and a bunch of radio energy
1793 and oftentimes you find few perfect solutions. This chapter
1794 contains some suggestions about how to install Altus Metrum
1795 products into the rocket air-frame, including how to safely and
1796 reliably mix a variety of electronics into the same air-frame.
1799 <title>Mounting the Altimeter</title>
1801 The first consideration is to ensure that the altimeter is
1802 securely fastened to the air-frame. For TeleMetrum, we use
1803 nylon standoffs and nylon screws; they're good to at least 50G
1804 and cannot cause any electrical issues on the board. For
1805 TeleMini, we usually cut small pieces of 1/16" balsa to fit
1806 under the screw holes, and then take 2x56 nylon screws and
1807 screw them through the TeleMini mounting holes, through the
1808 balsa and into the underlying material.
1810 <orderedlist inheritnum='inherit' numeration='arabic'>
1812 Make sure TeleMetrum is aligned precisely along the axis of
1813 acceleration so that the accelerometer can accurately
1814 capture data during the flight.
1817 Watch for any metal touching components on the
1818 board. Shorting out connections on the bottom of the board
1819 can cause the altimeter to fail during flight.
1824 <title>Dealing with the Antenna</title>
1826 The antenna supplied is just a piece of solid, insulated,
1827 wire. If it gets damaged or broken, it can be easily
1828 replaced. It should be kept straight and not cut; bending or
1829 cutting it will change the resonant frequency and/or
1830 impedance, making it a less efficient radiator and thus
1831 reducing the range of the telemetry signal.
1834 Keeping metal away from the antenna will provide better range
1835 and a more even radiation pattern. In most rockets, it's not
1836 entirely possible to isolate the antenna from metal
1837 components; there are often bolts, all-thread and wires from other
1838 electronics to contend with. Just be aware that the more stuff
1839 like this around the antenna, the lower the range.
1842 Make sure the antenna is not inside a tube made or covered
1843 with conducting material. Carbon fiber is the most common
1844 culprit here -- CF is a good conductor and will effectively
1845 shield the antenna, dramatically reducing signal strength and
1846 range. Metallic flake paint is another effective shielding
1847 material which is to be avoided around any antennas.
1850 If the ebay is large enough, it can be convenient to simply
1851 mount the altimeter at one end and stretch the antenna out
1852 inside. Taping the antenna to the sled can keep it straight
1853 under acceleration. If there are metal rods, keep the
1854 antenna as far away as possible.
1857 For a shorter ebay, it's quite practical to have the antenna
1858 run through a bulkhead and into an adjacent bay. Drill a small
1859 hole in the bulkhead, pass the antenna wire through it and
1860 then seal it up with glue or clay. We've also used acrylic
1861 tubing to create a cavity for the antenna wire. This works a
1862 bit better in that the antenna is known to stay straight and
1863 not get folded by recovery components in the bay. Angle the
1864 tubing towards the side wall of the rocket and it ends up
1865 consuming very little space.
1868 If you need to place the antenna at a distance from the
1869 altimeter, you can replace the antenna with an edge-mounted
1870 SMA connector, and then run 50Ω coax from the board to the
1871 antenna. Building a remote antenna is beyond the scope of this
1876 <title>Preserving GPS Reception</title>
1878 The GPS antenna and receiver in TeleMetrum are highly
1879 sensitive and normally have no trouble tracking enough
1880 satellites to provide accurate position information for
1881 recovering the rocket. However, there are many ways to
1882 attenuate the GPS signal.
1883 <orderedlist inheritnum='inherit' numeration='arabic'>
1885 Conductive tubing or coatings. Carbon fiber and metal
1886 tubing, or metallic paint will all dramatically attenuate the
1887 GPS signal. We've never heard of anyone successfully
1888 receiving GPS from inside these materials.
1891 Metal components near the GPS patch antenna. These will
1892 de-tune the patch antenna, changing the resonant frequency
1893 away from the L1 carrier and reduce the effectiveness of the
1894 antenna. You can place as much stuff as you like beneath the
1895 antenna as that's covered with a ground plane. But, keep
1896 wires and metal out from above the patch antenna.
1902 <title>Radio Frequency Interference</title>
1904 Any altimeter will generate RFI; the digital circuits use
1905 high-frequency clocks that spray radio interference across a
1906 wide band. Altus Metrum altimeters generate intentional radio
1907 signals as well, increasing the amount of RF energy around the board.
1910 Rocketry altimeters also use precise sensors measuring air
1911 pressure and acceleration. Tiny changes in voltage can cause
1912 these sensor readings to vary by a huge amount. When the
1913 sensors start mis-reporting data, the altimeter can either
1914 fire the igniters at the wrong time, or not fire them at all.
1917 Voltages are induced when radio frequency energy is
1918 transmitted from one circuit to another. Here are things that
1919 influence the induced voltage and current:
1923 Keep wires from different circuits apart. Moving circuits
1924 further apart will reduce RFI.
1927 Avoid parallel wires from different circuits. The longer two
1928 wires run parallel to one another, the larger the amount of
1929 transferred energy. Cross wires at right angles to reduce
1933 Twist wires from the same circuits. Two wires the same
1934 distance from the transmitter will get the same amount of
1935 induced energy which will then cancel out. Any time you have
1936 a wire pair running together, twist the pair together to
1937 even out distances and reduce RFI. For altimeters, this
1938 includes battery leads, switch hookups and igniter
1942 Avoid resonant lengths. Know what frequencies are present
1943 in the environment and avoid having wire lengths near a
1944 natural resonant length. Altusmetrum products transmit on the
1945 70cm amateur band, so you should avoid lengths that are a
1946 simple ratio of that length; essentially any multiple of 1/4
1947 of the wavelength (17.5cm).
1952 <title>The Barometric Sensor</title>
1954 Altusmetrum altimeters measure altitude with a barometric
1955 sensor, essentially measuring the amount of air above the
1956 rocket to figure out how high it is. A large number of
1957 measurements are taken as the altimeter initializes itself to
1958 figure out the pad altitude. Subsequent measurements are then
1959 used to compute the height above the pad.
1962 To accurately measure atmospheric pressure, the ebay
1963 containing the altimeter must be vented outside the
1964 air-frame. The vent must be placed in a region of linear
1965 airflow, have smooth edges, and away from areas of increasing or
1966 decreasing pressure.
1969 The barometric sensor in the altimeter is quite sensitive to
1970 chemical damage from the products of APCP or BP combustion, so
1971 make sure the ebay is carefully sealed from any compartment
1972 which contains ejection charges or motors.
1976 <title>Ground Testing</title>
1978 The most important aspect of any installation is careful
1979 ground testing. Bringing an air-frame up to the LCO table which
1980 hasn't been ground tested can lead to delays or ejection
1981 charges firing on the pad, or, even worse, a recovery system
1985 Do a 'full systems' test that includes wiring up all igniters
1986 without any BP and turning on all of the electronics in flight
1987 mode. This will catch any mistakes in wiring and any residual
1988 RFI issues that might accidentally fire igniters at the wrong
1989 time. Let the air-frame sit for several minutes, checking for
1990 adequate telemetry signal strength and GPS lock. If any igniters
1991 fire unexpectedly, find and resolve the issue before loading any
1995 Ground test the ejection charges. Prepare the rocket for
1996 flight, loading ejection charges and igniters. Completely
1997 assemble the air-frame and then use the 'Fire Igniters'
1998 interface through a TeleDongle to command each charge to
1999 fire. Make sure the charge is sufficient to robustly separate
2000 the air-frame and deploy the recovery system.
2005 <title>Updating Device Firmware</title>
2007 The big concept to understand is that you have to use a
2008 TeleDongle as a programmer to update a TeleMetrum or TeleMini,
2009 and a TeleMetrum or other TeleDongle to program the TeleDongle
2010 Due to limited memory resources in the cc1111, we don't support
2011 programming directly over USB.
2014 You may wish to begin by ensuring you have current firmware images.
2015 These are distributed as part of the AltOS software bundle that
2016 also includes the AltosUI ground station program. Newer ground
2017 station versions typically work fine with older firmware versions,
2018 so you don't need to update your devices just to try out new
2019 software features. You can always download the most recent
2020 version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
2023 We recommend updating the altimeter first, before updating TeleDongle.
2026 <title>Updating TeleMetrum Firmware</title>
2027 <orderedlist inheritnum='inherit' numeration='arabic'>
2029 Find the 'programming cable' that you got as part of the starter
2030 kit, that has a red 8-pin MicroMaTch connector on one end and a
2031 red 4-pin MicroMaTch connector on the other end.
2034 Take the 2 screws out of the TeleDongle case to get access
2035 to the circuit board.
2038 Plug the 8-pin end of the programming cable to the
2039 matching connector on the TeleDongle, and the 4-pin end to the
2040 matching connector on the TeleMetrum.
2041 Note that each MicroMaTch connector has an alignment pin that
2042 goes through a hole in the PC board when you have the cable
2046 Attach a battery to the TeleMetrum board.
2049 Plug the TeleDongle into your computer's USB port, and power
2053 Run AltosUI, and select 'Flash Image' from the File menu.
2056 Pick the TeleDongle device from the list, identifying it as the
2060 Select the image you want put on the TeleMetrum, which should have a
2061 name in the form telemetrum-v1.2-1.0.0.ihx. It should be visible
2062 in the default directory, if not you may have to poke around
2063 your system to find it.
2066 Make sure the configuration parameters are reasonable
2067 looking. If the serial number and/or RF configuration
2068 values aren't right, you'll need to change them.
2071 Hit the 'OK' button and the software should proceed to flash
2072 the TeleMetrum with new firmware, showing a progress bar.
2075 Confirm that the TeleMetrum board seems to have updated OK, which you
2076 can do by plugging in to it over USB and using a terminal program
2077 to connect to the board and issue the 'v' command to check
2081 If something goes wrong, give it another try.
2086 <title>Updating TeleMini Firmware</title>
2087 <orderedlist inheritnum='inherit' numeration='arabic'>
2089 You'll need a special 'programming cable' to reprogram the
2090 TeleMini. It's available on the Altus Metrum web store, or
2091 you can make your own using an 8-pin MicroMaTch connector on
2092 one end and a set of four pins on the other.
2095 Take the 2 screws out of the TeleDongle case to get access
2096 to the circuit board.
2099 Plug the 8-pin end of the programming cable to the matching
2100 connector on the TeleDongle, and the 4-pins into the holes
2101 in the TeleMini circuit board. Note that the MicroMaTch
2102 connector has an alignment pin that goes through a hole in
2103 the PC board when you have the cable oriented correctly, and
2104 that pin 1 on the TeleMini board is marked with a square pad
2105 while the other pins have round pads.
2108 Attach a battery to the TeleMini board.
2111 Plug the TeleDongle into your computer's USB port, and power
2115 Run AltosUI, and select 'Flash Image' from the File menu.
2118 Pick the TeleDongle device from the list, identifying it as the
2122 Select the image you want put on the TeleMini, which should have a
2123 name in the form telemini-v1.0-1.0.0.ihx. It should be visible
2124 in the default directory, if not you may have to poke around
2125 your system to find it.
2128 Make sure the configuration parameters are reasonable
2129 looking. If the serial number and/or RF configuration
2130 values aren't right, you'll need to change them.
2133 Hit the 'OK' button and the software should proceed to flash
2134 the TeleMini with new firmware, showing a progress bar.
2137 Confirm that the TeleMini board seems to have updated OK, which you
2138 can do by configuring it over the radio link through the TeleDongle, or
2139 letting it come up in "flight" mode and listening for telemetry.
2142 If something goes wrong, give it another try.
2147 <title>Updating TeleDongle Firmware</title>
2149 Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
2150 firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
2152 <orderedlist inheritnum='inherit' numeration='arabic'>
2154 Find the 'programming cable' that you got as part of the starter
2155 kit, that has a red 8-pin MicroMaTch connector on one end and a
2156 red 4-pin MicroMaTch connector on the other end.
2159 Find the USB cable that you got as part of the starter kit, and
2160 plug the "mini" end in to the mating connector on TeleMetrum or TeleDongle.
2163 Take the 2 screws out of the TeleDongle case to get access
2164 to the circuit board.
2167 Plug the 8-pin end of the programming cable to the
2168 matching connector on the programmer, and the 4-pin end to the
2169 matching connector on the TeleDongle.
2170 Note that each MicroMaTch connector has an alignment pin that
2171 goes through a hole in the PC board when you have the cable
2175 Attach a battery to the TeleMetrum board if you're using one.
2178 Plug both the programmer and the TeleDongle into your computer's USB
2179 ports, and power up the programmer.
2182 Run AltosUI, and select 'Flash Image' from the File menu.
2185 Pick the programmer device from the list, identifying it as the
2189 Select the image you want put on the TeleDongle, which should have a
2190 name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
2191 in the default directory, if not you may have to poke around
2192 your system to find it.
2195 Make sure the configuration parameters are reasonable
2196 looking. If the serial number and/or RF configuration
2197 values aren't right, you'll need to change them. The TeleDongle
2198 serial number is on the "bottom" of the circuit board, and can
2199 usually be read through the translucent blue plastic case without
2200 needing to remove the board from the case.
2203 Hit the 'OK' button and the software should proceed to flash
2204 the TeleDongle with new firmware, showing a progress bar.
2207 Confirm that the TeleDongle board seems to have updated OK, which you
2208 can do by plugging in to it over USB and using a terminal program
2209 to connect to the board and issue the 'v' command to check
2210 the version, etc. Once you're happy, remove the programming cable
2211 and put the cover back on the TeleDongle.
2214 If something goes wrong, give it another try.
2218 Be careful removing the programming cable from the locking 8-pin
2219 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
2220 screwdriver or knife blade to gently pry the locking ears out
2221 slightly to extract the connector. We used a locking connector on
2222 TeleMetrum to help ensure that the cabling to companion boards
2223 used in a rocket don't ever come loose accidentally in flight.
2228 <title>Hardware Specifications</title>
2230 <title>TeleMetrum Specifications</title>
2234 Recording altimeter for model rocketry.
2239 Supports dual deployment (can fire 2 ejection charges).
2244 70cm ham-band transceiver for telemetry down-link.
2249 Barometric pressure sensor good to 45k feet MSL.
2254 1-axis high-g accelerometer for motor characterization, capable of
2255 +/- 50g using default part.
2260 On-board, integrated GPS receiver with 5Hz update rate capability.
2265 On-board 1 megabyte non-volatile memory for flight data storage.
2270 USB interface for battery charging, configuration, and data recovery.
2275 Fully integrated support for Li-Po rechargeable batteries.
2280 Uses Li-Po to fire e-matches, can be modified to support
2281 optional separate pyro battery if needed.
2286 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
2292 <title>TeleMini Specifications</title>
2296 Recording altimeter for model rocketry.
2301 Supports dual deployment (can fire 2 ejection charges).
2306 70cm ham-band transceiver for telemetry down-link.
2311 Barometric pressure sensor good to 45k feet MSL.
2316 On-board 5 kilobyte non-volatile memory for flight data storage.
2321 RF interface for configuration, and data recovery.
2326 Support for Li-Po rechargeable batteries, using an external charger.
2331 Uses Li-Po to fire e-matches, can be modified to support
2332 optional separate pyro battery if needed.
2337 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube.
2346 TeleMetrum seems to shut off when disconnected from the
2347 computer. Make sure the battery is adequately charged. Remember the
2348 unit will pull more power than the USB port can deliver before the
2349 GPS enters "locked" mode. The battery charges best when TeleMetrum
2353 It's impossible to stop the TeleDongle when it's in "p" mode, I have
2354 to unplug the USB cable? Make sure you have tried to "escape out" of
2355 this mode. If this doesn't work the reboot procedure for the
2356 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
2357 outgoing buffer IF your "escape out" ('~~') does not work.
2358 At this point using either 'ao-view' (or possibly
2359 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
2363 The amber LED (on the TeleMetrum) lights up when both
2364 battery and USB are connected. Does this mean it's charging?
2365 Yes, the yellow LED indicates the charging at the 'regular' rate.
2366 If the led is out but the unit is still plugged into a USB port,
2367 then the battery is being charged at a 'trickle' rate.
2370 There are no "dit-dah-dah-dit" sound or lights like the manual mentions?
2371 That's the "pad" mode. Weak batteries might be the problem.
2372 It is also possible that the TeleMetrum is horizontal and the output
2373 is instead a "dit-dit" meaning 'idle'. For TeleMini, it's possible that
2374 it received a command packet which would have left it in "pad" mode.
2377 How do I save flight data?
2378 Live telemetry is written to file(s) whenever AltosUI is connected
2379 to the TeleDongle. The file area defaults to ~/TeleMetrum
2380 but is easily changed using the menus in AltosUI. The files that
2381 are written end in '.telem'. The after-flight
2382 data-dumped files will end in .eeprom and represent continuous data
2383 unlike the .telem files that are subject to losses
2384 along the RF data path.
2385 See the above instructions on what and how to save the eeprom stored
2386 data after physically retrieving your altimeter. Make sure to save
2387 the on-board data after each flight; while the TeleMetrum can store
2388 multiple flights, you never know when you'll lose the altimeter...
2392 <title>Notes for Older Software</title>
2395 Before AltosUI was written, using Altus Metrum devices required
2396 some finesse with the Linux command line. There was a limited
2397 GUI tool, ao-view, which provided functionality similar to the
2398 Monitor Flight window in AltosUI, but everything else was a
2399 fairly 80's experience. This appendix includes documentation for
2400 using that software.
2404 Both TeleMetrum and TeleDongle can be directly communicated
2405 with using USB ports. The first thing you should try after getting
2406 both units plugged into to your computer's USB port(s) is to run
2407 'ao-list' from a terminal-window to see what port-device-name each
2408 device has been assigned by the operating system.
2409 You will need this information to access the devices via their
2410 respective on-board firmware and data using other command line
2411 programs in the AltOS software suite.
2414 TeleMini can be communicated with through a TeleDongle device
2415 over the radio link. When first booted, TeleMini listens for a
2416 TeleDongle device and if it receives a packet, it goes into
2417 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be
2418 launched. The easiest way to get it talking is to start the
2419 communication link on the TeleDongle and the power up the
2423 To access the device's firmware for configuration you need a terminal
2424 program such as you would use to talk to a modem. The software
2425 authors prefer using the program 'cu' which comes from the UUCP package
2426 on most Unix-like systems such as Linux. An example command line for
2427 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
2428 indicated from running the
2429 ao-list program. Another reasonable terminal program for Linux is
2430 'cutecom'. The default 'escape'
2431 character used by CU (i.e. the character you use to
2432 issue commands to cu itself instead of sending the command as input
2433 to the connected device) is a '~'. You will need this for use in
2434 only two different ways during normal operations. First is to exit
2435 the program by sending a '~.' which is called a 'escape-disconnect'
2436 and allows you to close-out from 'cu'. The
2437 second use will be outlined later.
2440 All of the Altus Metrum devices share the concept of a two level
2441 command set in their firmware.
2442 The first layer has several single letter commands. Once
2443 you are using 'cu' (or 'cutecom') sending (typing) a '?'
2444 returns a full list of these
2445 commands. The second level are configuration sub-commands accessed
2446 using the 'c' command, for
2447 instance typing 'c?' will give you this second level of commands
2448 (all of which require the
2449 letter 'c' to access). Please note that most configuration options
2450 are stored only in Flash memory; TeleDongle doesn't provide any storage
2451 for these options and so they'll all be lost when you unplug it.
2454 Try setting these configuration ('c' or second level menu) values. A good
2455 place to start is by setting your call sign. By default, the boards
2456 use 'N0CALL' which is cute, but not exactly legal!
2457 Spend a few minutes getting comfortable with the units, their
2458 firmware, and 'cu' (or possibly 'cutecom').
2459 For instance, try to send
2460 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
2461 Verify you can connect and disconnect from the units while in your
2462 terminal program by sending the escape-disconnect mentioned above.
2465 To set the radio frequency, use the 'c R' command to specify the
2466 radio transceiver configuration parameter. This parameter is computed
2467 using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
2468 the standard calibration reference frequency, 'S', (normally 434.550MHz):
2472 Round the result to the nearest integer value.
2473 As with all 'c' sub-commands, follow this with a 'c w' to write the
2474 change to the parameter block in the on-board flash on
2475 your altimeter board if you want the change to stay in place across reboots.
2478 To set the apogee delay, use the 'c d' command.
2479 As with all 'c' sub-commands, follow this with a 'c w' to write the
2480 change to the parameter block in the on-board DataFlash chip.
2483 To set the main deployment altitude, use the 'c m' command.
2484 As with all 'c' sub-commands, follow this with a 'c w' to write the
2485 change to the parameter block in the on-board DataFlash chip.
2488 To calibrate the radio frequency, connect the UHF antenna port to a
2489 frequency counter, set the board to 434.550MHz, and use the 'C'
2490 command to generate a CW carrier. Wait for the transmitter temperature
2491 to stabilize and the frequency to settle down.
2492 Then, divide 434.550 MHz by the
2493 measured frequency and multiply by the current radio cal value show
2494 in the 'c s' command. For an unprogrammed board, the default value
2495 is 1186611. Take the resulting integer and program it using the 'c f'
2496 command. Testing with the 'C' command again should show a carrier
2497 within a few tens of Hertz of the intended frequency.
2498 As with all 'c' sub-commands, follow this with a 'c w' to write the
2499 change to the parameter block in the on-board DataFlash chip.
2502 Note that the 'reboot' command, which is very useful on the altimeters,
2503 will likely just cause problems with the dongle. The *correct* way
2504 to reset the dongle is just to unplug and re-plug it.
2507 A fun thing to do at the launch site and something you can do while
2508 learning how to use these units is to play with the radio link access
2509 between an altimeter and the TeleDongle. Be aware that you *must* create
2510 some physical separation between the devices, otherwise the link will
2511 not function due to signal overload in the receivers in each device.
2514 Now might be a good time to take a break and read the rest of this
2515 manual, particularly about the two "modes" that the altimeters
2516 can be placed in. TeleMetrum uses the position of the device when booting
2517 up will determine whether the unit is in "pad" or "idle" mode. TeleMini
2518 enters "idle" mode when it receives a command packet within the first 5 seconds
2519 of being powered up, otherwise it enters "pad" mode.
2522 You can access an altimeter in idle mode from the TeleDongle's USB
2523 connection using the radio link
2524 by issuing a 'p' command to the TeleDongle. Practice connecting and
2525 disconnecting ('~~' while using 'cu') from the altimeter. If
2526 you cannot escape out of the "p" command, (by using a '~~' when in
2527 CU) then it is likely that your kernel has issues. Try a newer version.
2530 Using this radio link allows you to configure the altimeter, test
2531 fire e-matches and igniters from the flight line, check pyro-match
2532 continuity and so forth. You can leave the unit turned on while it
2533 is in 'idle mode' and then place the
2534 rocket vertically on the launch pad, walk away and then issue a
2535 reboot command. The altimeter will reboot and start sending data
2536 having changed to the "pad" mode. If the TeleDongle is not receiving
2537 this data, you can disconnect 'cu' from the TeleDongle using the
2538 procedures mentioned above and THEN connect to the TeleDongle from
2539 inside 'ao-view'. If this doesn't work, disconnect from the
2540 TeleDongle, unplug it, and try again after plugging it back in.
2543 In order to reduce the chance of accidental firing of pyrotechnic
2544 charges, the command to fire a charge is intentionally somewhat
2545 difficult to type, and the built-in help is slightly cryptic to
2546 prevent accidental echoing of characters from the help text back at
2547 the board from firing a charge. The command to fire the apogee
2548 drogue charge is 'i DoIt drogue' and the command to fire the main
2549 charge is 'i DoIt main'.
2552 On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
2553 and 'ao-view' will both auditorily announce and visually indicate
2555 Now you can launch knowing that you have a good data path and
2556 good satellite lock for flight data and recovery. Remember
2557 you MUST tell ao-view to connect to the TeleDongle explicitly in
2558 order for ao-view to be able to receive data.
2561 The altimeters provide RDF (radio direction finding) tones on
2562 the pad, during descent and after landing. These can be used to
2563 locate the rocket using a directional antenna; the signal
2564 strength providing an indication of the direction from receiver to rocket.
2567 TeleMetrum also provides GPS tracking data, which can further simplify
2568 locating the rocket once it has landed. (The last good GPS data
2569 received before touch-down will be on the data screen of 'ao-view'.)
2572 Once you have recovered the rocket you can download the eeprom
2573 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
2574 either a USB cable or over the radio link using TeleDongle.
2575 And by following the man page for 'ao-postflight' you can create
2576 various data output reports, graphs, and even KML data to see the
2577 flight trajectory in Google-earth. (Moving the viewing angle making
2578 sure to connect the yellow lines while in Google-earth is the proper
2582 As for ao-view.... some things are in the menu but don't do anything
2583 very useful. The developers have stopped working on ao-view to focus
2584 on a new, cross-platform ground station program. So ao-view may or
2585 may not be updated in the future. Mostly you just use
2586 the Log and Device menus. It has a wonderful display of the incoming
2587 flight data and I am sure you will enjoy what it has to say to you
2588 once you enable the voice output!
2592 <title>Drill Templates</title>
2594 These images, when printed, provide precise templates for the
2595 mounting holes in Altus Metrum flight computers
2598 <title>TeleMetrum template</title>
2600 TeleMetrum has overall dimensions of 1.000 x 2.750 inches, and the
2601 mounting holes are sized for use with 4-40 or M3 screws.
2603 <mediaobject id="TeleMetrumTemplate">
2605 <imagedata format="SVG" fileref="telemetrum.svg"/>
2610 <title>TeleMini template</title>
2612 TeleMini has overall dimensions of 0.500 x 1.500 inches, and the
2613 mounting holes are sized for use with 2-56 or M2 screws.
2615 <mediaobject id="TeleMiniTemplate">
2617 <imagedata format="SVG" fileref="telemini.svg"/>
2623 <title>Calibration</title>
2625 There are only two calibrations required for a TeleMetrum board, and
2626 only one for TeleDongle and TeleMini. All boards are shipped from
2627 the factory pre-calibrated, but the procedures are documented here
2628 in case they are ever needed. Re-calibration is not supported by
2629 AltosUI, you must connect to the board with a serial terminal program
2630 and interact directly with the on-board command interpreter to effect
2634 <title>Radio Frequency</title>
2636 The radio frequency is synthesized from a clock based on the 48 MHz
2637 crystal on the board. The actual frequency of this oscillator
2638 must be measured to generate a calibration constant. While our
2640 bandwidth is wide enough to allow boards to communicate even when
2641 their oscillators are not on exactly the same frequency, performance
2642 is best when they are closely matched.
2643 Radio frequency calibration requires a calibrated frequency counter.
2644 Fortunately, once set, the variation in frequency due to aging and
2645 temperature changes is small enough that re-calibration by customers
2646 should generally not be required.
2649 To calibrate the radio frequency, connect the UHF antenna port to a
2650 frequency counter, set the board to 434.550MHz, and use the 'C'
2651 command in the on-board command interpreter to generate a CW
2652 carrier. For TeleMetrum, this is best done over USB. For TeleMini,
2653 note that the only way to escape the 'C' command is via power cycle
2654 since the board will no longer be listening for commands once it
2655 starts generating a CW carrier.
2658 Wait for the transmitter temperature to stabilize and the frequency
2659 to settle down. Then, divide 434.550 MHz by the
2660 measured frequency and multiply by the current radio cal value show
2661 in the 'c s' command. For an unprogrammed board, the default value
2662 is 1186611. Take the resulting integer and program it using the 'c f'
2663 command. Testing with the 'C' command again should show a carrier
2664 within a few tens of Hertz of the intended frequency.
2665 As with all 'c' sub-commands, follow this with a 'c w' to write the
2666 change to the parameter block in the on-board DataFlash chip.
2669 Note that any time you re-do the radio frequency calibration, the
2670 radio frequency is reset to the default 434.550 Mhz. If you want
2671 to use another frequency, you will have to set that again after
2672 calibration is completed.
2676 <title>TeleMetrum Accelerometer</title>
2678 The TeleMetrum accelerometer we use has its own 5 volt power
2680 the output must be passed through a resistive voltage divider to match
2681 the input of our 3.3 volt ADC. This means that unlike the barometric
2682 sensor, the output of the acceleration sensor is not ratio-metric to
2683 the ADC converter, and calibration is required. Explicitly
2684 calibrating the accelerometers also allows us to load any device
2685 from a Freescale family that includes at least +/- 40g, 50g, 100g,
2686 and 200g parts. Using gravity,
2687 a simple 2-point calibration yields acceptable results capturing both
2688 the different sensitivities and ranges of the different accelerometer
2689 parts and any variation in power supply voltages or resistor values
2690 in the divider network.
2693 To calibrate the acceleration sensor, use the 'c a 0' command. You
2694 will be prompted to orient the board vertically with the UHF antenna
2695 up and press a key, then to orient the board vertically with the
2696 UHF antenna down and press a key. Note that the accuracy of this
2697 calibration depends primarily on how perfectly vertical and still
2698 the board is held during the cal process. As with all 'c'
2699 sub-commands, follow this with a 'c w' to write the
2700 change to the parameter block in the on-board DataFlash chip.
2703 The +1g and -1g calibration points are included in each telemetry
2704 frame and are part of the header stored in onboard flash to be
2705 downloaded after flight. We always store and return raw ADC
2706 samples for each sensor... so nothing is permanently "lost" or
2707 "damaged" if the calibration is poor.
2710 In the unlikely event an accel cal goes badly, it is possible
2711 that TeleMetrum may always come up in 'pad mode' and as such not be
2712 listening to either the USB or radio link. If that happens,
2713 there is a special hook in the firmware to force the board back
2714 in to 'idle mode' so you can re-do the cal. To use this hook, you
2715 just need to ground the SPI clock pin at power-on. This pin is
2716 available as pin 2 on the 8-pin companion connector, and pin 1 is
2717 ground. So either carefully install a fine-gauge wire jumper
2718 between the two pins closest to the index hole end of the 8-pin
2719 connector, or plug in the programming cable to the 8-pin connector
2720 and use a small screwdriver or similar to short the two pins closest
2721 to the index post on the 4-pin end of the programming cable, and
2722 power up the board. It should come up in 'idle mode' (two beeps),
2728 xmlns:xi="http://www.w3.org/2001/XInclude">
2729 <title>Release Notes</title>
2730 <simplesect><title>Version 1.2</title><xi:include href="release-notes-1.2.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2731 <simplesect><title>Version 1.1.1</title><xi:include href="release-notes-1.1.1.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2732 <simplesect><title>Version 1.1</title><xi:include href="release-notes-1.1.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2733 <simplesect><title>Version 1.0.1</title><xi:include href="release-notes-1.0.1.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2734 <simplesect><title>Version 0.9.2</title><xi:include href="release-notes-0.9.2.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2735 <simplesect><title>Version 0.9</title><xi:include href="release-notes-0.9.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2736 <simplesect><title>Version 0.8</title><xi:include href="release-notes-0.8.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2737 <simplesect><title>Version 0.7.1</title><xi:include href="release-notes-0.7.1.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2741 <!-- LocalWords: Altusmetrum
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