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5 <title>The Altus Metrum System</title>
6 <subtitle>An Owner's Manual for TeleMetrum, TeleMini, TeleDongle and TeleBT 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>1.2.1</revnumber>
40 <date>21 May 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 bugs in AltosUI and the AltOS firmware.
48 <revnumber>1.2</revnumber>
49 <date>18 April 2013</date>
51 Updated for software version 1.2. Version 1.2 adds support
52 for MicroPeak and the MicroPeak USB interface.
56 <revnumber>1.1.1</revnumber>
57 <date>16 September 2012</date>
59 Updated for software version 1.1.1 Version 1.1.1 fixes a few
60 bugs found in version 1.1.
64 <revnumber>1.1</revnumber>
65 <date>13 September 2012</date>
67 Updated for software version 1.1. Version 1.1 has new
68 features but is otherwise compatible with version 1.0.
72 <revnumber>1.0</revnumber>
73 <date>24 August 2011</date>
75 Updated for software version 1.0. Note that 1.0 represents a
76 telemetry format change, meaning both ends of a link
77 (TeleMetrum/TeleMini and TeleDongle) must be updated or
78 communications will fail.
82 <revnumber>0.9</revnumber>
83 <date>18 January 2011</date>
85 Updated for software version 0.9. Note that 0.9 represents a
86 telemetry format change, meaning both ends of a link (TeleMetrum and
87 TeleDongle) must be updated or communications will fail.
91 <revnumber>0.8</revnumber>
92 <date>24 November 2010</date>
93 <revremark>Updated for software version 0.8 </revremark>
99 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing "The
100 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
101 Kit" which formed the basis of the original Getting Started chapter
102 in this manual. Bob was one of our first customers for a production
103 TeleMetrum, and his continued enthusiasm and contributions
104 are immensely gratifying and highly appreciated!
107 And thanks to Anthony (AJ) Towns for major contributions including
108 the AltosUI graphing and site map code and associated documentation.
109 Free software means that our customers and friends can become our
110 collaborators, and we certainly appreciate this level of
114 Have fun using these products, and we hope to meet all of you
115 out on the rocket flight line somewhere.
118 NAR #87103, TRA #12201
120 Keith Packard, KD7SQG
121 NAR #88757, TRA #12200
126 <title>Introduction and Overview</title>
128 Welcome to the Altus Metrum community! Our circuits and software reflect
129 our passion for both hobby rocketry and Free Software. We hope their
130 capabilities and performance will delight you in every way, but by
131 releasing all of our hardware and software designs under open licenses,
132 we also hope to empower you to take as active a role in our collective
136 The first device created for our community was TeleMetrum, a dual
137 deploy altimeter with fully integrated GPS and radio telemetry
138 as standard features, and a "companion interface" that will
139 support optional capabilities in the future.
142 Our second device was TeleMini, a dual deploy altimeter with
143 radio telemetry and radio direction finding. This device is only
144 13mm by 38mm (½ inch by 1½ inches) and can fit easily in an 18mm
148 TeleDongle was our first ground station, providing a USB to RF
149 interfaces for communicating with the altimeters. Combined with
150 your choice of antenna and notebook computer, TeleDongle and our
151 associated user interface software form a complete ground
152 station capable of logging and displaying in-flight telemetry,
153 aiding rocket recovery, then processing and archiving flight
154 data for analysis and review.
157 For a slightly more portable ground station experience that also
158 provides direct rocket recovery support, TeleBT offers flight
159 monitoring and data logging using a Bluetooth connection between
160 the receiver and an Android device that has the Altos Droid
161 application installed from the Google Play store.
164 More products will be added to the Altus Metrum family over time, and
165 we currently envision that this will be a single, comprehensive manual
166 for the entire product family.
170 <title>Getting Started</title>
172 The first thing to do after you check the inventory of parts in your
173 "starter kit" is to charge the battery.
176 The TeleMetrum battery can be charged by plugging it into the
177 corresponding socket of the TeleMetrum and then using the USB A to
179 cable to plug the TeleMetrum into your computer's USB socket. The
180 TeleMetrum circuitry will charge the battery whenever it is plugged
181 in, because the TeleMetrum's on-off switch does NOT control the
185 When the GPS chip is initially searching for
186 satellites, TeleMetrum will consume more current than it can pull
187 from the USB port, so the battery must be attached in order to get
188 satellite lock. Once GPS is locked, the current consumption goes back
189 down enough to enable charging while
190 running. So it's a good idea to fully charge the battery as your
191 first item of business so there is no issue getting and maintaining
192 satellite lock. The yellow charge indicator led will go out when the
193 battery is nearly full and the charger goes to trickle charge. It
194 can take several hours to fully recharge a deeply discharged battery.
197 The TeleMini battery can be charged by disconnecting it from the
198 TeleMini board and plugging it into a standalone battery charger
199 such as the LipoCharger product included in TeleMini Starter Kits,
200 and connecting that via a USB cable to a laptop or other USB
204 The other active device in the starter kit is the TeleDongle USB to
205 RF interface. If you plug it in to your Mac or Linux computer it should
206 "just work", showing up as a serial port device. Windows systems need
207 driver information that is part of the AltOS download to know that the
208 existing USB modem driver will work. We therefore recommend installing
209 our software before plugging in TeleDongle if you are using a Windows
210 computer. If you are using Linux and are having problems, try moving
211 to a fresher kernel (2.6.33 or newer), as the USB serial driver had
212 ugly bugs in some earlier versions.
215 Next you should obtain and install the AltOS software. These include
216 the AltosUI ground station program, current firmware images for
217 TeleMetrum, TeleMini and TeleDongle, and a number of standalone
218 utilities that are rarely needed. Pre-built binary packages are
219 available for Linux, Microsoft Windows, and recent MacOSX versions.
220 Full source code and build instructions are also available.
221 The latest version may always be downloaded from
222 <ulink url="http://altusmetrum.org/AltOS"/>.
225 If you're using a TeleBT instead of the TeleDongle, you'll want
226 to go install the Altos Droid application from the Google Play
227 store. You don't need a data plan to use Altos Droid, but
228 without network access, the Map view will be less useful as it
229 won't contain any map data. You can also use TeleBT connected
230 over USB with your laptop computer; it acts exactly like a
231 TeleDongle. Anywhere this manual talks about TeleDongle, you can
232 also read that as 'and TeleBT when connected via USB'.
236 <title>Handling Precautions</title>
238 All Altus Metrum products are sophisticated electronic devices.
239 When handled gently and properly installed in an air-frame, they
240 will deliver impressive results. However, as with all electronic
241 devices, there are some precautions you must take.
244 The Lithium Polymer rechargeable batteries have an
245 extraordinary power density. This is great because we can fly with
246 much less battery mass than if we used alkaline batteries or previous
247 generation rechargeable batteries... but if they are punctured
248 or their leads are allowed to short, they can and will release their
250 Thus we recommend that you take some care when handling our batteries
251 and consider giving them some extra protection in your air-frame. We
252 often wrap them in suitable scraps of closed-cell packing foam before
253 strapping them down, for example.
256 The barometric sensors used on both TeleMetrum and TeleMini are
257 sensitive to sunlight. In normal TeleMetrum mounting situations, it
258 and all of the other surface mount components
259 are "down" towards whatever the underlying mounting surface is, so
260 this is not normally a problem. Please consider this, though, when
261 designing an installation, for example, in an air-frame with a
262 see-through plastic payload bay. It is particularly important to
263 consider this with TeleMini, both because the baro sensor is on the
264 "top" of the board, and because many model rockets with payload bays
265 use clear plastic for the payload bay! Replacing these with an opaque
266 cardboard tube, painting them, or wrapping them with a layer of masking
267 tape are all reasonable approaches to keep the sensor out of direct
271 The barometric sensor sampling port must be able to "breathe",
272 both by not being covered by foam or tape or other materials that might
273 directly block the hole on the top of the sensor, and also by having a
274 suitable static vent to outside air.
277 As with all other rocketry electronics, Altus Metrum altimeters must
278 be protected from exposure to corrosive motor exhaust and ejection
283 <title>Hardware Overview</title>
285 TeleMetrum is a 1 inch by 2.75 inch circuit board. It was designed to
286 fit inside coupler for 29mm air-frame tubing, but using it in a tube that
287 small in diameter may require some creativity in mounting and wiring
288 to succeed! The presence of an accelerometer means TeleMetrum should
289 be aligned along the flight axis of the airframe, and by default the 1/4
290 wave UHF wire antenna should be on the nose-cone end of the board. The
291 antenna wire is about 7 inches long, and wiring for a power switch and
292 the e-matches for apogee and main ejection charges depart from the
293 fin can end of the board, meaning an ideal "simple" avionics
294 bay for TeleMetrum should have at least 10 inches of interior length.
297 TeleMini is a 0.5 inch by 1.5 inch circuit board. It was designed to
298 fit inside an 18mm air-frame tube, but using it in a tube that
299 small in diameter may require some creativity in mounting and wiring
300 to succeed! Since there is no accelerometer, TeleMini can be mounted
301 in any convenient orientation. The default 1/4
302 wave UHF wire antenna attached to the center of one end of
303 the board is about 7 inches long, and wiring for a power switch and
304 the e-matches for apogee and main ejection charges depart from the
305 other end of the board, meaning an ideal "simple" avionics
306 bay for TeleMini should have at least 9 inches of interior length.
309 A typical TeleMetrum or TeleMini installation involves attaching
310 only a suitable Lithium Polymer battery, a single pole switch for
311 power on/off, and two pairs of wires connecting e-matches for the
312 apogee and main ejection charges. All Altus Metrum products are
313 designed for use with single-cell batteries with 3.7 volts nominal.
316 The battery connectors are a standard 2-pin JST connector and
317 match batteries sold by Spark Fun. These batteries are
318 single-cell Lithium Polymer batteries that nominally provide 3.7
319 volts. Other vendors sell similar batteries for RC aircraft
320 using mating connectors, however the polarity for those is
321 generally reversed from the batteries used by Altus Metrum
322 products. In particular, the Tenergy batteries supplied for use
323 in Featherweight flight computers are not compatible with Altus
324 Metrum flight computers or battery chargers. <emphasis>Check
325 polarity and voltage before connecting any battery not purchased
326 from Altus Metrum or Spark Fun.</emphasis>
329 By default, we use the unregulated output of the Li-Po battery directly
330 to fire ejection charges. This works marvelously with standard
331 low-current e-matches like the J-Tek from MJG Technologies, and with
332 Quest Q2G2 igniters. However, if you want or need to use a separate
333 pyro battery, check out the "External Pyro Battery" section in this
334 manual for instructions on how to wire that up. The altimeters are
335 designed to work with an external pyro battery of no more than 15 volts.
338 Ejection charges are wired directly to the screw terminal block
339 at the aft end of the altimeter. You'll need a very small straight
340 blade screwdriver for these screws, such as you might find in a
341 jeweler's screwdriver set.
344 TeleMetrum also uses the screw terminal block for the power
345 switch leads. On TeleMini, the power switch leads are soldered
346 directly to the board and can be connected directly to a switch.
349 For most air-frames, the integrated antennas are more than
350 adequate. However, if you are installing in a carbon-fiber or
351 metal electronics bay which is opaque to RF signals, you may need to
352 use off-board external antennas instead. In this case, you can
353 order an altimeter with an SMA connector for the UHF antenna
354 connection, and, on TeleMetrum, you can unplug the integrated GPS
355 antenna and select an appropriate off-board GPS antenna with
356 cable terminating in a U.FL connector.
360 <title>System Operation</title>
362 <title>Firmware Modes </title>
364 The AltOS firmware build for the altimeters has two
365 fundamental modes, "idle" and "flight". Which of these modes
366 the firmware operates in is determined at start up time. For
367 TeleMetrum, the mode is controlled by the orientation of the
368 rocket (well, actually the board, of course...) at the time
369 power is switched on. If the rocket is "nose up", then
370 TeleMetrum assumes it's on a rail or rod being prepared for
371 launch, so the firmware chooses flight mode. However, if the
372 rocket is more or less horizontal, the firmware instead enters
373 idle mode. Since TeleMini doesn't have an accelerometer we can
374 use to determine orientation, "idle" mode is selected when the
375 board receives a command packet within the first five seconds
376 of operation; if no packet is received, the board enters
380 At power on, you will hear three beeps or see three flashes
381 ("S" in Morse code for start up) and then a pause while
382 the altimeter completes initialization and self test, and decides
383 which mode to enter next.
386 In flight or "pad" mode, the altimeter engages the flight
387 state machine, goes into transmit-only mode to
388 send telemetry, and waits for launch to be detected.
389 Flight mode is indicated by an "di-dah-dah-dit" ("P" for pad)
390 on the beeper or lights, followed by beeps or flashes
391 indicating the state of the pyrotechnic igniter continuity.
392 One beep/flash indicates apogee continuity, two beeps/flashes
393 indicate main continuity, three beeps/flashes indicate both
394 apogee and main continuity, and one longer "brap" sound or
395 rapidly alternating lights indicates no continuity. For a
396 dual deploy flight, make sure you're getting three beeps or
397 flashes before launching! For apogee-only or motor eject
398 flights, do what makes sense.
401 If idle mode is entered, you will hear an audible "di-dit" or
402 see two short flashes ("I" for idle), and the flight state
403 machine is disengaged, thus no ejection charges will fire.
404 The altimeters also listen for the radio link when in idle
405 mode for requests sent via TeleDongle. Commands can be issued
406 to a TeleMetrum in idle mode over either USB or the radio link
407 equivalently. TeleMini only has the radio link. Idle mode is
408 useful for configuring the altimeter, for extracting data from
409 the on-board storage chip after flight, and for ground testing
413 One "neat trick" of particular value when TeleMetrum is used with
414 very large air-frames, is that you can power the board up while the
415 rocket is horizontal, such that it comes up in idle mode. Then you can
416 raise the air-frame to launch position, and issue a 'reset' command
417 via TeleDongle over the radio link to cause the altimeter to reboot and
418 come up in flight mode. This is much safer than standing on the top
419 step of a rickety step-ladder or hanging off the side of a launch
420 tower with a screw-driver trying to turn on your avionics before
424 TeleMini is configured via the radio link. Of course, that
425 means you need to know the TeleMini radio configuration values
426 or you won't be able to communicate with it. For situations
427 when you don't have the radio configuration values, TeleMini
428 offers an 'emergency recovery' mode. In this mode, TeleMini is
429 configured as follows:
432 Sets the radio frequency to 434.550MHz
435 Sets the radio calibration back to the factory value.
438 Sets the callsign to N0CALL
441 Does not go to 'pad' mode after five seconds.
446 To get into 'emergency recovery' mode, first find the row of
447 four small holes opposite the switch wiring. Using a short
448 piece of small gauge wire, connect the outer two holes
449 together, then power TeleMini up. Once the red LED is lit,
450 disconnect the wire and the board should signal that it's in
451 'idle' mode after the initial five second startup period.
457 TeleMetrum includes a complete GPS receiver. A complete explanation
458 of how GPS works is beyond the scope of this manual, but the bottom
459 line is that the TeleMetrum GPS receiver needs to lock onto at least
460 four satellites to obtain a solid 3 dimensional position fix and know
464 TeleMetrum provides backup power to the GPS chip any time a
465 battery is connected. This allows the receiver to "warm start" on
466 the launch rail much faster than if every power-on were a GPS
467 "cold start". In typical operations, powering up TeleMetrum
468 on the flight line in idle mode while performing final air-frame
469 preparation will be sufficient to allow the GPS receiver to cold
470 start and acquire lock. Then the board can be powered down during
471 RSO review and installation on a launch rod or rail. When the board
472 is turned back on, the GPS system should lock very quickly, typically
473 long before igniter installation and return to the flight line are
478 <title>Controlling An Altimeter Over The Radio Link</title>
480 One of the unique features of the Altus Metrum system is the
481 ability to create a two way command link between TeleDongle
482 and an altimeter using the digital radio transceivers
483 built into each device. This allows you to interact with the
484 altimeter from afar, as if it were directly connected to the
488 Any operation which can be performed with TeleMetrum can
489 either be done with TeleMetrum directly connected to the
490 computer via the USB cable, or through the radio
491 link. TeleMini doesn't provide a USB connector and so it is
492 always communicated with over radio. Select the appropriate
493 TeleDongle device when the list of devices is presented and
494 AltosUI will interact with an altimeter over the radio link.
497 One oddity in the current interface is how AltosUI selects the
498 frequency for radio communications. Instead of providing
499 an interface to specifically configure the frequency, it uses
500 whatever frequency was most recently selected for the target
501 TeleDongle device in Monitor Flight mode. If you haven't ever
502 used that mode with the TeleDongle in question, select the
503 Monitor Flight button from the top level UI, and pick the
504 appropriate TeleDongle device. Once the flight monitoring
505 window is open, select the desired frequency and then close it
506 down again. All radio communications will now use that frequency.
511 Save Flight Data—Recover flight data from the rocket without
517 Configure altimeter apogee delays or main deploy heights
518 to respond to changing launch conditions. You can also
519 'reboot' the altimeter. Use this to remotely enable the
520 flight computer by turning TeleMetrum on in "idle" mode,
521 then once the air-frame is oriented for launch, you can
522 reboot the altimeter and have it restart in pad mode
523 without having to climb the scary ladder.
528 Fire Igniters—Test your deployment charges without snaking
529 wires out through holes in the air-frame. Simply assembly the
530 rocket as if for flight with the apogee and main charges
531 loaded, then remotely command the altimeter to fire the
537 Operation over the radio link for configuring an altimeter, ground
538 testing igniters, and so forth uses the same RF frequencies as flight
539 telemetry. To configure the desired TeleDongle frequency, select
540 the monitor flight tab, then use the frequency selector and
541 close the window before performing other desired radio operations.
544 TeleMetrum only enables radio commanding in 'idle' mode, so
545 make sure you have TeleMetrum lying horizontally when you turn
546 it on. Otherwise, TeleMetrum will start in 'pad' mode ready for
547 flight, and will not be listening for command packets from TeleDongle.
550 TeleMini listens for a command packet for five seconds after
551 first being turned on, if it doesn't hear anything, it enters
552 'pad' mode, ready for flight and will no longer listen for
553 command packets. The easiest way to connect to TeleMini is to
554 initiate the command and select the TeleDongle device. At this
555 point, the TeleDongle will be attempting to communicate with
556 the TeleMini. Now turn TeleMini on, and it should immediately
557 start communicating with the TeleDongle and the desired
558 operation can be performed.
561 You can monitor the operation of the radio link by watching the
562 lights on the devices. The red LED will flash each time a packet
563 is transmitted, while the green LED will light up on TeleDongle when
564 it is waiting to receive a packet from the altimeter.
568 <title>Ground Testing </title>
570 An important aspect of preparing a rocket using electronic deployment
571 for flight is ground testing the recovery system. Thanks
572 to the bi-directional radio link central to the Altus Metrum system,
573 this can be accomplished in a TeleMetrum or TeleMini equipped rocket
574 with less work than you may be accustomed to with other systems. It
578 Just prep the rocket for flight, then power up the altimeter
579 in "idle" mode (placing air-frame horizontal for TeleMetrum or
580 selected the Configure Altimeter tab for TeleMini). This will cause
581 the firmware to go into "idle" mode, in which the normal flight
582 state machine is disabled and charges will not fire without
583 manual command. You can now command the altimeter to fire the apogee
584 or main charges from a safe distance using your computer and
585 TeleDongle and the Fire Igniter tab to complete ejection testing.
589 <title>Radio Link </title>
591 The chip our boards are based on incorporates an RF transceiver, but
592 it's not a full duplex system... each end can only be transmitting or
593 receiving at any given moment. So we had to decide how to manage the
597 By design, the altimeter firmware listens for the radio link when
598 it's in "idle mode", which
599 allows us to use the radio link to configure the rocket, do things like
600 ejection tests, and extract data after a flight without having to
601 crack open the air-frame. However, when the board is in "flight
602 mode", the altimeter only
603 transmits and doesn't listen at all. That's because we want to put
604 ultimate priority on event detection and getting telemetry out of
606 the radio in case the rocket crashes and we aren't able to extract
610 We don't use a 'normal packet radio' mode like APRS because they're
611 just too inefficient. The GFSK modulation we use is FSK with the
612 base-band pulses passed through a
613 Gaussian filter before they go into the modulator to limit the
614 transmitted bandwidth. When combined with the hardware forward error
615 correction support in the cc1111 chip, this allows us to have a very
616 robust 38.4 kilobit data link with only 10 milliwatts of transmit
617 power, a whip antenna in the rocket, and a hand-held Yagi on the
618 ground. We've had flights to above 21k feet AGL with great reception,
619 and calculations suggest we should be good to well over 40k feet AGL
620 with a 5-element yagi on the ground. We hope to fly boards to higher
621 altitudes over time, and would of course appreciate customer feedback
622 on performance in higher altitude flights!
626 <title>Configurable Parameters</title>
628 Configuring an Altus Metrum altimeter for flight is very
629 simple. Even on our baro-only TeleMini board, the use of a Kalman
630 filter means there is no need to set a "mach delay". The few
631 configurable parameters can all be set using AltosUI over USB or
632 or radio link via TeleDongle.
635 <title>Radio Frequency</title>
637 Altus Metrum boards support radio frequencies in the 70cm
638 band. By default, the configuration interface provides a
639 list of 10 "standard" frequencies in 100kHz channels starting at
640 434.550MHz. However, the firmware supports use of
641 any 50kHz multiple within the 70cm band. At any given
642 launch, we highly recommend coordinating when and by whom each
643 frequency will be used to avoid interference. And of course, both
644 altimeter and TeleDongle must be configured to the same
645 frequency to successfully communicate with each other.
649 <title>Apogee Delay</title>
651 Apogee delay is the number of seconds after the altimeter detects flight
652 apogee that the drogue charge should be fired. In most cases, this
653 should be left at the default of 0. However, if you are flying
654 redundant electronics such as for an L3 certification, you may wish
655 to set one of your altimeters to a positive delay so that both
656 primary and backup pyrotechnic charges do not fire simultaneously.
659 The Altus Metrum apogee detection algorithm fires exactly at
660 apogee. If you are also flying an altimeter like the
661 PerfectFlite MAWD, which only supports selecting 0 or 1
662 seconds of apogee delay, you may wish to set the MAWD to 0
663 seconds delay and set the TeleMetrum to fire your backup 2
664 or 3 seconds later to avoid any chance of both charges
665 firing simultaneously. We've flown several air-frames this
666 way quite happily, including Keith's successful L3 cert.
670 <title>Main Deployment Altitude</title>
672 By default, the altimeter will fire the main deployment charge at an
673 elevation of 250 meters (about 820 feet) above ground. We think this
674 is a good elevation for most air-frames, but feel free to change this
675 to suit. In particular, if you are flying two altimeters, you may
677 deployment elevation for the backup altimeter to be something lower
678 than the primary so that both pyrotechnic charges don't fire
683 <title>Maximum Flight Log</title>
685 TeleMetrum version 1.1 and 1.2 have 2MB of on-board flash storage,
686 enough to hold over 40 minutes of data at full data rate
687 (100 samples/second). TeleMetrum 1.0 has 1MB of on-board
688 storage. As data are stored at a reduced rate during descent
689 (10 samples/second), there's plenty of space to store many
690 flights worth of data.
693 The on-board flash is partitioned into separate flight logs,
694 each of a fixed maximum size. Increase the maximum size of
695 each log and you reduce the number of flights that can be
696 stored. Decrease the size and TeleMetrum can store more
700 All of the configuration data is also stored in the flash
701 memory, which consumes 64kB on TeleMetrum v1.1/v1.2 and 256B on
702 TeleMetrum v1.0. This configuration space is not available
703 for storing flight log data.
706 To compute the amount of space needed for a single flight,
707 you can multiply the expected ascent time (in seconds) by
708 800, multiply the expected descent time (in seconds) by 80
709 and add the two together. That will slightly under-estimate
710 the storage (in bytes) needed for the flight. For instance,
711 a flight spending 20 seconds in ascent and 150 seconds in
712 descent will take about (20 * 800) + (150 * 80) = 28000
713 bytes of storage. You could store dozens of these flights in
717 The default size, 192kB, allows for 10 flights of storage on
718 TeleMetrum v1.1/v1.2 and 5 flights on TeleMetrum v1.0. This
719 ensures that you won't need to erase the memory before
720 flying each time while still allowing more than sufficient
721 storage for each flight.
724 As TeleMini does not contain an accelerometer, it stores
725 data at 10 samples per second during ascent and one sample
726 per second during descent. Each sample is a two byte reading
727 from the barometer. These are stored in 5kB of
728 on-chip flash memory which can hold 256 seconds at the
729 ascent rate or 2560 seconds at the descent rate. Because of
730 the limited storage, TeleMini cannot hold data for more than
731 one flight, and so must be erased after each flight or it
732 will not capture data for subsequent flights.
736 <title>Ignite Mode</title>
738 Instead of firing one charge at apogee and another charge at
739 a fixed height above the ground, you can configure the
740 altimeter to fire both at apogee or both during
741 descent. This was added to support an airframe that has two
742 TeleMetrum computers, one in the fin can and one in the
746 Providing the ability to use both igniters for apogee or
747 main allows some level of redundancy without needing two
748 flight computers. In Redundant Apogee or Redundant Main
749 mode, the two charges will be fired two seconds apart.
753 <title>Pad Orientation</title>
755 TeleMetrum measures acceleration along the axis of the
756 board. Which way the board is oriented affects the sign of
757 the acceleration value. Instead of trying to guess which way
758 the board is mounted in the air frame, TeleMetrum must be
759 explicitly configured for either Antenna Up or Antenna
760 Down. The default, Antenna Up, expects the end of the
761 TeleMetrum board connected to the 70cm antenna to be nearest
762 the nose of the rocket, with the end containing the screw
763 terminals nearest the tail.
771 <title>AltosUI</title>
773 The AltosUI program provides a graphical user interface for
774 interacting with the Altus Metrum product family, including
775 TeleMetrum, TeleMini and TeleDongle. AltosUI can monitor telemetry data,
776 configure TeleMetrum, TeleMini and TeleDongle devices and many other
777 tasks. The primary interface window provides a selection of
778 buttons, one for each major activity in the system. This manual
779 is split into chapters, each of which documents one of the tasks
780 provided from the top-level toolbar.
783 <title>Monitor Flight</title>
784 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
786 Selecting this item brings up a dialog box listing all of the
787 connected TeleDongle devices. When you choose one of these,
788 AltosUI will create a window to display telemetry data as
789 received by the selected TeleDongle device.
792 All telemetry data received are automatically recorded in
793 suitable log files. The name of the files includes the current
794 date and rocket serial and flight numbers.
797 The radio frequency being monitored by the TeleDongle device is
798 displayed at the top of the window. You can configure the
799 frequency by clicking on the frequency box and selecting the desired
800 frequency. AltosUI remembers the last frequency selected for each
801 TeleDongle and selects that automatically the next time you use
805 Below the TeleDongle frequency selector, the window contains a few
806 significant pieces of information about the altimeter providing
807 the telemetry data stream:
811 <para>The configured call-sign</para>
814 <para>The device serial number</para>
817 <para>The flight number. Each altimeter remembers how many
823 The rocket flight state. Each flight passes through several
824 states including Pad, Boost, Fast, Coast, Drogue, Main and
830 The Received Signal Strength Indicator value. This lets
831 you know how strong a signal TeleDongle is receiving. The
832 radio inside TeleDongle operates down to about -99dBm;
833 weaker signals may not be receivable. The packet link uses
834 error detection and correction techniques which prevent
835 incorrect data from being reported.
840 The age of the displayed data, in seconds since the last
841 successfully received telemetry packet. In normal operation
842 this will stay in the low single digits. If the number starts
843 counting up, then you are no longer receiving data over the radio
844 link from the flight computer.
849 Finally, the largest portion of the window contains a set of
850 tabs, each of which contain some information about the rocket.
851 They're arranged in 'flight order' so that as the flight
852 progresses, the selected tab automatically switches to display
853 data relevant to the current state of the flight. You can select
854 other tabs at any time. The final 'table' tab displays all of
855 the raw telemetry values in one place in a spreadsheet-like format.
858 <title>Launch Pad</title>
860 The 'Launch Pad' tab shows information used to decide when the
861 rocket is ready for flight. The first elements include red/green
862 indicators, if any of these is red, you'll want to evaluate
863 whether the rocket is ready to launch:
867 Battery Voltage. This indicates whether the Li-Po battery
868 powering the TeleMetrum has sufficient charge to last for
869 the duration of the flight. A value of more than
870 3.7V is required for a 'GO' status.
875 Apogee Igniter Voltage. This indicates whether the apogee
876 igniter has continuity. If the igniter has a low
877 resistance, then the voltage measured here will be close
878 to the Li-Po battery voltage. A value greater than 3.2V is
879 required for a 'GO' status.
884 Main Igniter Voltage. This indicates whether the main
885 igniter has continuity. If the igniter has a low
886 resistance, then the voltage measured here will be close
887 to the Li-Po battery voltage. A value greater than 3.2V is
888 required for a 'GO' status.
893 On-board Data Logging. This indicates whether there is
894 space remaining on-board to store flight data for the
895 upcoming flight. If you've downloaded data, but failed
896 to erase flights, there may not be any space
897 left. TeleMetrum can store multiple flights, depending
898 on the configured maximum flight log size. TeleMini
899 stores only a single flight, so it will need to be
900 downloaded and erased after each flight to capture
901 data. This only affects on-board flight logging; the
902 altimeter will still transmit telemetry and fire
903 ejection charges at the proper times.
908 GPS Locked. For a TeleMetrum device, this indicates whether the GPS receiver is
909 currently able to compute position information. GPS requires
910 at least 4 satellites to compute an accurate position.
915 GPS Ready. For a TeleMetrum device, this indicates whether GPS has reported at least
916 10 consecutive positions without losing lock. This ensures
917 that the GPS receiver has reliable reception from the
923 The Launchpad tab also shows the computed launch pad position
924 and altitude, averaging many reported positions to improve the
930 <title>Ascent</title>
932 This tab is shown during Boost, Fast and Coast
933 phases. The information displayed here helps monitor the
934 rocket as it heads towards apogee.
937 The height, speed and acceleration are shown along with the
938 maximum values for each of them. This allows you to quickly
939 answer the most commonly asked questions you'll hear during
943 The current latitude and longitude reported by the TeleMetrum GPS are
944 also shown. Note that under high acceleration, these values
945 may not get updated as the GPS receiver loses position
946 fix. Once the rocket starts coasting, the receiver should
947 start reporting position again.
950 Finally, the current igniter voltages are reported as in the
951 Launch Pad tab. This can help diagnose deployment failures
952 caused by wiring which comes loose under high acceleration.
956 <title>Descent</title>
958 Once the rocket has reached apogee and (we hope) activated the
959 apogee charge, attention switches to tracking the rocket on
960 the way back to the ground, and for dual-deploy flights,
961 waiting for the main charge to fire.
964 To monitor whether the apogee charge operated correctly, the
965 current descent rate is reported along with the current
966 height. Good descent rates vary based on the choice of recovery
967 components, but generally range from 15-30m/s on drogue and should
968 be below 10m/s when under the main parachute in a dual-deploy flight.
971 For TeleMetrum altimeters, you can locate the rocket in the
972 sky using the elevation and bearing information to figure
973 out where to look. Elevation is in degrees above the
974 horizon. Bearing is reported in degrees relative to true
975 north. Range can help figure out how big the rocket will
976 appear. Ground Distance shows how far it is to a point
977 directly under the rocket and can help figure out where the
978 rocket is likely to land. Note that all of these values are
979 relative to the pad location. If the elevation is near 90°,
980 the rocket is over the pad, not over you.
983 Finally, the igniter voltages are reported in this tab as
984 well, both to monitor the main charge as well as to see what
985 the status of the apogee charge is. Note that some commercial
986 e-matches are designed to retain continuity even after being
987 fired, and will continue to show as green or return from red to
992 <title>Landed</title>
994 Once the rocket is on the ground, attention switches to
995 recovery. While the radio signal is often lost once the
996 rocket is on the ground, the last reported GPS position is
997 generally within a short distance of the actual landing location.
1000 The last reported GPS position is reported both by
1001 latitude and longitude as well as a bearing and distance from
1002 the launch pad. The distance should give you a good idea of
1003 whether to walk or hitch a ride. Take the reported
1004 latitude and longitude and enter them into your hand-held GPS
1005 unit and have that compute a track to the landing location.
1008 Both TeleMini and TeleMetrum will continue to transmit RDF
1009 tones after landing, allowing you to locate the rocket by
1010 following the radio signal if necessary. You may need to get
1011 away from the clutter of the flight line, or even get up on
1012 a hill (or your neighbor's RV roof) to receive the RDF signal.
1015 The maximum height, speed and acceleration reported
1016 during the flight are displayed for your admiring observers.
1017 The accuracy of these immediate values depends on the quality
1018 of your radio link and how many packets were received.
1019 Recovering the on-board data after flight will likely yield
1020 more precise results.
1023 To get more detailed information about the flight, you can
1024 click on the 'Graph Flight' button which will bring up a
1025 graph window for the current flight.
1029 <title>Site Map</title>
1031 When the TeleMetrum has a GPS fix, the Site Map tab will map
1032 the rocket's position to make it easier for you to locate the
1033 rocket, both while it is in the air, and when it has landed. The
1034 rocket's state is indicated by color: white for pad, red for
1035 boost, pink for fast, yellow for coast, light blue for drogue,
1036 dark blue for main, and black for landed.
1039 The map's scale is approximately 3m (10ft) per pixel. The map
1040 can be dragged using the left mouse button. The map will attempt
1041 to keep the rocket roughly centered while data is being received.
1044 Images are fetched automatically via the Google Maps Static API,
1045 and cached on disk for reuse. If map images cannot be downloaded,
1046 the rocket's path will be traced on a dark gray background
1050 You can pre-load images for your favorite launch sites
1051 before you leave home; check out the 'Preload Maps' section below.
1056 <title>Save Flight Data</title>
1058 The altimeter records flight data to its internal flash memory.
1059 TeleMetrum data is recorded at a much higher rate than the telemetry
1060 system can handle, and is not subject to radio drop-outs. As
1061 such, it provides a more complete and precise record of the
1062 flight. The 'Save Flight Data' button allows you to read the
1063 flash memory and write it to disk. As TeleMini has only a barometer, it
1064 records data at the same rate as the telemetry signal, but there will be
1065 no data lost due to telemetry drop-outs.
1068 Clicking on the 'Save Flight Data' button brings up a list of
1069 connected TeleMetrum and TeleDongle devices. If you select a
1070 TeleMetrum device, the flight data will be downloaded from that
1071 device directly. If you select a TeleDongle device, flight data
1072 will be downloaded from an altimeter over radio link via the
1073 specified TeleDongle. See the chapter on Controlling An Altimeter
1074 Over The Radio Link for more information.
1077 After the device has been selected, a dialog showing the
1078 flight data saved in the device will be shown allowing you to
1079 select which flights to download and which to delete. With
1080 version 0.9 or newer firmware, you must erase flights in order
1081 for the space they consume to be reused by another
1082 flight. This prevents accidentally losing flight data
1083 if you neglect to download data before flying again. Note that
1084 if there is no more space available in the device, then no
1085 data will be recorded during the next flight.
1088 The file name for each flight log is computed automatically
1089 from the recorded flight date, altimeter serial number and
1090 flight number information.
1094 <title>Replay Flight</title>
1096 Select this button and you are prompted to select a flight
1097 record file, either a .telem file recording telemetry data or a
1098 .eeprom file containing flight data saved from the altimeter
1102 Once a flight record is selected, the flight monitor interface
1103 is displayed and the flight is re-enacted in real time. Check
1104 the Monitor Flight chapter above to learn how this window operates.
1108 <title>Graph Data</title>
1110 Select this button and you are prompted to select a flight
1111 record file, either a .telem file recording telemetry data or a
1112 .eeprom file containing flight data saved from
1116 Once a flight record is selected, a window with four tabs is
1117 opened. The first tab contains a graph with acceleration
1118 (blue), velocity (green) and altitude (red) of the flight,
1119 measured in metric units. The apogee(yellow) and main(magenta)
1120 igniter voltages are also displayed; high voltages indicate
1121 continuity, low voltages indicate open circuits. The second
1122 tab lets you configure which data to show in the graph. The
1123 third contains some basic flight statistics while the fourth
1124 has a map with the ground track of the flight displayed.
1127 The graph can be zoomed into a particular area by clicking and
1128 dragging down and to the right. Once zoomed, the graph can be
1129 reset by clicking and dragging up and to the left. Holding down
1130 control and clicking and dragging allows the graph to be panned.
1131 The right mouse button causes a pop-up menu to be displayed, giving
1132 you the option save or print the plot.
1135 Note that telemetry files will generally produce poor graphs
1136 due to the lower sampling rate and missed telemetry packets.
1137 Use saved flight data in .eeprom files for graphing where possible.
1141 <title>Export Data</title>
1143 This tool takes the raw data files and makes them available for
1144 external analysis. When you select this button, you are prompted to
1146 data file (either .eeprom or .telem will do, remember that
1147 .eeprom files contain higher resolution and more continuous
1148 data). Next, a second dialog appears which is used to select
1149 where to write the resulting file. It has a selector to choose
1150 between CSV and KML file formats.
1153 <title>Comma Separated Value Format</title>
1155 This is a text file containing the data in a form suitable for
1156 import into a spreadsheet or other external data analysis
1157 tool. The first few lines of the file contain the version and
1158 configuration information from the altimeter, then
1159 there is a single header line which labels all of the
1160 fields. All of these lines start with a '#' character which
1161 many tools can be configured to skip over.
1164 The remaining lines of the file contain the data, with each
1165 field separated by a comma and at least one space. All of
1166 the sensor values are converted to standard units, with the
1167 barometric data reported in both pressure, altitude and
1168 height above pad units.
1172 <title>Keyhole Markup Language (for Google Earth)</title>
1174 This is the format used by Google Earth to provide an overlay
1175 within that application. With this, you can use Google Earth to
1176 see the whole flight path in 3D.
1181 <title>Configure Altimeter</title>
1183 Select this button and then select either a TeleMetrum or
1184 TeleDongle Device from the list provided. Selecting a TeleDongle
1185 device will use the radio link to configure a remote altimeter.
1188 The first few lines of the dialog provide information about the
1189 connected device, including the product name,
1190 software version and hardware serial number. Below that are the
1191 individual configuration entries.
1194 At the bottom of the dialog, there are four buttons:
1199 Save. This writes any changes to the
1200 configuration parameter block in flash memory. If you don't
1201 press this button, any changes you make will be lost.
1206 Reset. This resets the dialog to the most recently saved values,
1207 erasing any changes you have made.
1212 Reboot. This reboots the device. Use this to
1213 switch from idle to pad mode by rebooting once the rocket is
1214 oriented for flight, or to confirm changes you think you saved
1220 Close. This closes the dialog. Any unsaved changes will be
1226 The rest of the dialog contains the parameters to be configured.
1229 <title>Main Deploy Altitude</title>
1231 This sets the altitude (above the recorded pad altitude) at
1232 which the 'main' igniter will fire. The drop-down menu shows
1233 some common values, but you can edit the text directly and
1234 choose whatever you like. If the apogee charge fires below
1235 this altitude, then the main charge will fire two seconds
1236 after the apogee charge fires.
1240 <title>Apogee Delay</title>
1242 When flying redundant electronics, it's often important to
1243 ensure that multiple apogee charges don't fire at precisely
1244 the same time, as that can over pressurize the apogee deployment
1245 bay and cause a structural failure of the air-frame. The Apogee
1246 Delay parameter tells the flight computer to fire the apogee
1247 charge a certain number of seconds after apogee has been
1252 <title>Radio Frequency</title>
1254 This configures which of the configured frequencies to use for both
1255 telemetry and packet command mode. Note that if you set this
1256 value via packet command mode, you will have to reconfigure
1257 the TeleDongle frequency before you will be able to use packet
1262 <title>Radio Calibration</title>
1264 The radios in every Altus Metrum device are calibrated at the
1265 factory to ensure that they transmit and receive on the
1266 specified frequency. If you need to you can adjust the calibration
1267 by changing this value. Do not do this without understanding what
1268 the value means, read the appendix on calibration and/or the source
1269 code for more information. To change a TeleDongle's calibration,
1270 you must reprogram the unit completely.
1274 <title>Callsign</title>
1276 This sets the call sign included in each telemetry packet. Set this
1277 as needed to conform to your local radio regulations.
1281 <title>Maximum Flight Log Size</title>
1283 This sets the space (in kilobytes) allocated for each flight
1284 log. The available space will be divided into chunks of this
1285 size. A smaller value will allow more flights to be stored,
1286 a larger value will record data from longer flights.
1290 <title>Ignite Mode</title>
1292 TeleMetrum and TeleMini provide two igniter channels as they
1293 were originally designed as dual-deploy flight
1294 computers. This configuration parameter allows the two
1295 channels to be used in different configurations.
1300 Dual Deploy. This is the usual mode of operation; the
1301 'apogee' channel is fired at apogee and the 'main'
1302 channel at the height above ground specified by the
1303 'Main Deploy Altitude' during descent.
1308 Redundant Apogee. This fires both channels at
1309 apogee, the 'apogee' channel first followed after a two second
1310 delay by the 'main' channel.
1315 Redundant Main. This fires both channels at the
1316 height above ground specified by the Main Deploy
1317 Altitude setting during descent. The 'apogee'
1318 channel is fired first, followed after a two second
1319 delay by the 'main' channel.
1325 <title>Pad Orientation</title>
1327 Because it includes an accelerometer, TeleMetrum is
1328 sensitive to the orientation of the board. By default, it
1329 expects the antenna end to point forward. This parameter
1330 allows that default to be changed, permitting the board to
1331 be mounted with the antenna pointing aft instead.
1336 Antenna Up. In this mode, the antenna end of the
1337 TeleMetrum board must point forward, in line with the
1338 expected flight path.
1343 Antenna Down. In this mode, the antenna end of the
1344 TeleMetrum board must point aft, in line with the
1345 expected flight path.
1352 <title>Configure AltosUI</title>
1354 This button presents a dialog so that you can configure the AltosUI global settings.
1357 <title>Voice Settings</title>
1359 AltosUI provides voice announcements during flight so that you
1360 can keep your eyes on the sky and still get information about
1361 the current flight status. However, sometimes you don't want
1366 <para>Enable—turns all voice announcements on and off</para>
1370 Test Voice—Plays a short message allowing you to verify
1371 that the audio system is working and the volume settings
1378 <title>Log Directory</title>
1380 AltosUI logs all telemetry data and saves all TeleMetrum flash
1381 data to this directory. This directory is also used as the
1382 staring point when selecting data files for display or export.
1385 Click on the directory name to bring up a directory choosing
1386 dialog, select a new directory and click 'Select Directory' to
1387 change where AltosUI reads and writes data files.
1391 <title>Callsign</title>
1393 This value is transmitted in each command packet sent from
1394 TeleDongle and received from an altimeter. It is not used in
1395 telemetry mode, as the callsign configured in the altimeter board
1396 is included in all telemetry packets. Configure this
1397 with the AltosUI operators call sign as needed to comply with
1398 your local radio regulations.
1401 Note that to successfully command a flight computer over the radio
1402 (to configure the altimeter, monitor idle, or fire pyro charges),
1403 the callsign configured here must exactly match the callsign
1404 configured in the flight computer. This matching is case
1409 <title>Imperial Units</title>
1411 This switches between metric units (meters) and imperial
1412 units (feet and miles). This affects the display of values
1413 use during flight monitoring, data graphing and all of the
1414 voice announcements. It does not change the units used when
1415 exporting to CSV files, those are always produced in metric units.
1419 <title>Font Size</title>
1421 Selects the set of fonts used in the flight monitor
1422 window. Choose between the small, medium and large sets.
1426 <title>Serial Debug</title>
1428 This causes all communication with a connected device to be
1429 dumped to the console from which AltosUI was started. If
1430 you've started it from an icon or menu entry, the output
1431 will simply be discarded. This mode can be useful to debug
1432 various serial communication issues.
1436 <title>Manage Frequencies</title>
1438 This brings up a dialog where you can configure the set of
1439 frequencies shown in the various frequency menus. You can
1440 add as many as you like, or even reconfigure the default
1441 set. Changing this list does not affect the frequency
1442 settings of any devices, it only changes the set of
1443 frequencies shown in the menus.
1448 <title>Configure Groundstation</title>
1450 Select this button and then select a TeleDongle Device from the list provided.
1453 The first few lines of the dialog provide information about the
1454 connected device, including the product name,
1455 software version and hardware serial number. Below that are the
1456 individual configuration entries.
1459 Note that the TeleDongle itself doesn't save any configuration
1460 data, the settings here are recorded on the local machine in
1461 the Java preferences database. Moving the TeleDongle to
1462 another machine, or using a different user account on the same
1463 machine will cause settings made here to have no effect.
1466 At the bottom of the dialog, there are three buttons:
1471 Save. This writes any changes to the
1472 local Java preferences file. If you don't
1473 press this button, any changes you make will be lost.
1478 Reset. This resets the dialog to the most recently saved values,
1479 erasing any changes you have made.
1484 Close. This closes the dialog. Any unsaved changes will be
1490 The rest of the dialog contains the parameters to be configured.
1493 <title>Frequency</title>
1495 This configures the frequency to use for both telemetry and
1496 packet command mode. Set this before starting any operation
1497 involving packet command mode so that it will use the right
1498 frequency. Telemetry monitoring mode also provides a menu to
1499 change the frequency, and that menu also sets the same Java
1500 preference value used here.
1504 <title>Radio Calibration</title>
1506 The radios in every Altus Metrum device are calibrated at the
1507 factory to ensure that they transmit and receive on the
1508 specified frequency. To change a TeleDongle's calibration,
1509 you must reprogram the unit completely, so this entry simply
1510 shows the current value and doesn't allow any changes.
1515 <title>Flash Image</title>
1517 This reprograms any Altus Metrum device by using a TeleMetrum
1518 or TeleDongle as a programming dongle. Please read the
1519 directions for flashing devices in the Updating Device
1520 Firmware chapter below.
1523 Once you have the programmer and target devices connected,
1524 push the 'Flash Image' button. That will present a dialog box
1525 listing all of the connected devices. Carefully select the
1526 programmer device, not the device to be programmed.
1529 Next, select the image to flash to the device. These are named
1530 with the product name and firmware version. The file selector
1531 will start in the directory containing the firmware included
1532 with the AltosUI package. Navigate to the directory containing
1533 the desired firmware if it isn't there.
1536 Next, a small dialog containing the device serial number and
1537 RF calibration values should appear. If these values are
1538 incorrect (possibly due to a corrupted image in the device),
1539 enter the correct values here.
1542 Finally, a dialog containing a progress bar will follow the
1543 programming process.
1546 When programming is complete, the target device will
1547 reboot. Note that if the target device is connected via USB, you
1548 will have to unplug it and then plug it back in for the USB
1549 connection to reset so that you can communicate with the device
1554 <title>Fire Igniter</title>
1556 This activates the igniter circuits in TeleMetrum to help test
1557 recovery systems deployment. Because this command can operate
1558 over the Packet Command Link, you can prepare the rocket as
1559 for flight and then test the recovery system without needing
1560 to snake wires inside the air-frame.
1563 Selecting the 'Fire Igniter' button brings up the usual device
1564 selection dialog. Pick the desired TeleDongle or TeleMetrum
1565 device. This brings up another window which shows the current
1566 continuity test status for both apogee and main charges.
1569 Next, select the desired igniter to fire. This will enable the
1573 Select the 'Arm' button. This enables the 'Fire' button. The
1574 word 'Arm' is replaced by a countdown timer indicating that
1575 you have 10 seconds to press the 'Fire' button or the system
1576 will deactivate, at which point you start over again at
1577 selecting the desired igniter.
1581 <title>Scan Channels</title>
1583 This listens for telemetry packets on all of the configured
1584 frequencies, displaying information about each device it
1585 receives a packet from. You can select which of the three
1586 telemetry formats should be tried; by default, it only listens
1587 for the standard telemetry packets used in v1.0 and later
1592 <title>Load Maps</title>
1594 Before heading out to a new launch site, you can use this to
1595 load satellite images in case you don't have internet
1596 connectivity at the site. This loads a fairly large area
1597 around the launch site, which should cover any flight you're likely to make.
1600 There's a drop-down menu of launch sites we know about; if
1601 your favorites aren't there, please let us know the lat/lon
1602 and name of the site. The contents of this list are actually
1603 downloaded at run-time, so as new sites are sent in, they'll
1604 get automatically added to this list.
1607 If the launch site isn't in the list, you can manually enter the lat/lon values
1610 Clicking the 'Load Map' button will fetch images from Google
1611 Maps; note that Google limits how many images you can fetch at
1612 once, so if you load more than one launch site, you may get
1613 some gray areas in the map which indicate that Google is tired
1614 of sending data to you. Try again later.
1618 <title>Monitor Idle</title>
1620 This brings up a dialog similar to the Monitor Flight UI,
1621 except it works with the altimeter in "idle" mode by sending
1622 query commands to discover the current state rather than
1623 listening for telemetry packets.
1628 <title>AltosDroid</title>
1630 AltosDroid provides the same flight monitoring capabilities as
1631 AltosUI, but runs on Android devices and is designed to connect
1632 to a TeleBT receiver over Bluetooth™. Altos Droid monitors
1633 telemetry data, logging it to internal storage in the Android
1634 device, and presents that data in a UI the same way the 'Monitor
1635 Flight' window does in AltosUI.
1638 This manual will explain how to configure AltosDroid, connect
1639 to TeleBT, operate the flight monitoring interface and describe
1640 what the displayed data means.
1643 <title>Installing AltosDroid</title>
1645 AltosDroid is included in the Google Play store. To install
1646 it on your Android device, open open the Google Play Store
1647 application and search for "altosdroid". Make sure you don't
1648 have a space between "altos" and "droid" or you probably won't
1649 find what you want. That should bring you to the right page
1650 from which you can download and install the application.
1654 <title>Connecting to TeleBT</title>
1656 Press the Android 'Menu' button or soft-key to see the
1657 configuration options available. Select the 'Connect a device'
1658 option and then the 'Scan for devices' entry at the bottom to
1659 look for your TeleBT device. Select your device, and when it
1660 asks for the code, enter '1234'.
1663 Subsequent connections will not require you to enter that
1664 code, and your 'paired' device will appear in the list without
1669 <title>Configuring AltosDroid</title>
1671 The only configuration option available for AltosDroid is
1672 which frequency to listen on. Press the Android 'Menu' button
1673 or soft-key and pick the 'Select radio frequency' entry. That
1674 brings up a menu of pre-set radio frequencies; pick the one
1675 which matches your altimeter.
1679 <title>Altos Droid Flight Monitoring</title>
1681 Altos Droid is designed to mimic the AltosUI flight monitoring
1682 display, providing separate tabs for each stage of your rocket
1683 flight along with a tab containing a map of the local area
1684 with icons marking the current location of the altimeter and
1690 The 'Launch Pad' tab shows information used to decide when the
1691 rocket is ready for flight. The first elements include red/green
1692 indicators, if any of these is red, you'll want to evaluate
1693 whether the rocket is ready to launch:
1697 Battery Voltage. This indicates whether the Li-Po battery
1698 powering the TeleMetrum has sufficient charge to last for
1699 the duration of the flight. A value of more than
1700 3.7V is required for a 'GO' status.
1705 Apogee Igniter Voltage. This indicates whether the apogee
1706 igniter has continuity. If the igniter has a low
1707 resistance, then the voltage measured here will be close
1708 to the Li-Po battery voltage. A value greater than 3.2V is
1709 required for a 'GO' status.
1714 Main Igniter Voltage. This indicates whether the main
1715 igniter has continuity. If the igniter has a low
1716 resistance, then the voltage measured here will be close
1717 to the Li-Po battery voltage. A value greater than 3.2V is
1718 required for a 'GO' status.
1723 On-board Data Logging. This indicates whether there is
1724 space remaining on-board to store flight data for the
1725 upcoming flight. If you've downloaded data, but failed
1726 to erase flights, there may not be any space
1727 left. TeleMetrum can store multiple flights, depending
1728 on the configured maximum flight log size. TeleMini
1729 stores only a single flight, so it will need to be
1730 downloaded and erased after each flight to capture
1731 data. This only affects on-board flight logging; the
1732 altimeter will still transmit telemetry and fire
1733 ejection charges at the proper times.
1738 GPS Locked. For a TeleMetrum device, this indicates whether the GPS receiver is
1739 currently able to compute position information. GPS requires
1740 at least 4 satellites to compute an accurate position.
1745 GPS Ready. For a TeleMetrum device, this indicates whether GPS has reported at least
1746 10 consecutive positions without losing lock. This ensures
1747 that the GPS receiver has reliable reception from the
1753 The Launchpad tab also shows the computed launch pad position
1754 and altitude, averaging many reported positions to improve the
1755 accuracy of the fix.
1761 <title>Downloading Flight Logs</title>
1763 Altos Droid always saves every bit of telemetry data it
1764 receives. To download that to a computer for use with AltosUI,
1765 simply remove the SD card from your Android device, or connect
1766 your device to your computer's USB port and browse the files
1767 on that device. You will find '.telem' files in the TeleMetrum
1768 directory that will work with AltosUI directly.
1773 <title>Using Altus Metrum Products</title>
1775 <title>Being Legal</title>
1777 First off, in the US, you need an <ulink url="http://www.altusmetrum.org/Radio/">amateur radio license</ulink> or
1778 other authorization to legally operate the radio transmitters that are part
1783 <title>In the Rocket</title>
1785 In the rocket itself, you just need a <ulink url="http://www.altusmetrum.org/TeleMetrum/">TeleMetrum</ulink> or
1786 <ulink url="http://www.altusmetrum.org/TeleMini/">TeleMini</ulink> board and
1787 a single-cell, 3.7 volt nominal Li-Po rechargeable battery. An
1788 850mAh battery weighs less than a 9V alkaline battery, and will
1789 run a TeleMetrum for hours.
1790 A 110mAh battery weighs less than a triple A battery and will run a TeleMetrum for
1791 a few hours, or a TeleMini for much (much) longer.
1794 By default, we ship the altimeters with a simple wire antenna. If your
1795 electronics bay or the air-frame it resides within is made of carbon fiber,
1796 which is opaque to RF signals, you may choose to have an SMA connector
1797 installed so that you can run a coaxial cable to an antenna mounted
1798 elsewhere in the rocket.
1802 <title>On the Ground</title>
1804 To receive the data stream from the rocket, you need an antenna and short
1805 feed-line connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. If possible, use an SMA to BNC
1806 adapter instead of feedline between the antenna feedpoint and
1807 TeleDongle, as this will give you the best performance. The
1808 TeleDongle in turn plugs directly into the USB port on a notebook
1809 computer. Because TeleDongle looks like a simple serial port, your computer
1810 does not require special device drivers... just plug it in.
1813 The GUI tool, AltosUI, is written in Java and runs across
1814 Linux, Mac OS and Windows. There's also a suite of C tools
1815 for Linux which can perform most of the same tasks.
1818 After the flight, you can use the radio link to extract the more detailed data
1819 logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
1820 TeleMetrum board directly. Pulling out the data without having to open up
1821 the rocket is pretty cool! A USB cable is also how you charge the Li-Po
1822 battery, so you'll want one of those anyway... the same cable used by lots
1823 of digital cameras and other modern electronic stuff will work fine.
1826 If your TeleMetrum-equipped rocket lands out of sight, you may enjoy having a hand-held GPS
1827 receiver, so that you can put in a way-point for the last reported rocket
1828 position before touch-down. This makes looking for your rocket a lot like
1829 Geo-Caching... just go to the way-point and look around starting from there.
1832 You may also enjoy having a ham radio "HT" that covers the 70cm band... you
1833 can use that with your antenna to direction-find the rocket on the ground
1834 the same way you can use a Walston or Beeline tracker. This can be handy
1835 if the rocket is hiding in sage brush or a tree, or if the last GPS position
1836 doesn't get you close enough because the rocket dropped into a canyon, or
1837 the wind is blowing it across a dry lake bed, or something like that... Keith
1838 and Bdale both currently own and use the Yaesu VX-7R at launches.
1841 So, to recap, on the ground the hardware you'll need includes:
1842 <orderedlist inheritnum='inherit' numeration='arabic'>
1844 an antenna and feed-line or adapter
1853 optionally, a hand-held GPS receiver
1856 optionally, an HT or receiver covering 435 MHz
1861 The best hand-held commercial directional antennas we've found for radio
1862 direction finding rockets are from
1863 <ulink url="http://www.arrowantennas.com/" >
1866 The 440-3 and 440-5 are both good choices for finding a
1867 TeleMetrum- or TeleMini- equipped rocket when used with a suitable
1868 70cm HT. TeleDongle and an SMA to BNC adapter fit perfectly
1869 between the driven element and reflector of Arrow antennas.
1873 <title>Data Analysis</title>
1875 Our software makes it easy to log the data from each flight, both the
1876 telemetry received during the flight itself, and the more
1877 complete data log recorded in the flash memory on the altimeter
1878 board. Once this data is on your computer, our post-flight tools make it
1879 easy to quickly get to the numbers everyone wants, like apogee altitude,
1880 max acceleration, and max velocity. You can also generate and view a
1881 standard set of plots showing the altitude, acceleration, and
1882 velocity of the rocket during flight. And you can even export a TeleMetrum data file
1883 usable with Google Maps and Google Earth for visualizing the flight path
1884 in two or three dimensions!
1887 Our ultimate goal is to emit a set of files for each flight that can be
1888 published as a web page per flight, or just viewed on your local disk with
1893 <title>Future Plans</title>
1895 In the future, we intend to offer "companion boards" for the rocket
1896 that will plug in to TeleMetrum to collect additional data, provide
1897 more pyro channels, and so forth.
1900 Also under design is a new flight computer with more sensors, more
1901 pyro channels, and a more powerful radio system designed for use
1902 in multi-stage, complex, and extreme altitude projects.
1905 We are also working on alternatives to TeleDongle. One is a
1906 a stand-alone, hand-held ground terminal that will allow monitoring
1907 the rocket's status, collecting data during flight, and logging data
1908 after flight without the need for a notebook computer on the
1909 flight line. Particularly since it is so difficult to read most
1910 notebook screens in direct sunlight, we think this will be a great
1911 thing to have. We are also working on a TeleDongle variant with
1912 Bluetooth that will work with Android phones and tablets.
1915 Because all of our work is open, both the hardware designs and the
1916 software, if you have some great idea for an addition to the current
1917 Altus Metrum family, feel free to dive in and help! Or let us know
1918 what you'd like to see that we aren't already working on, and maybe
1919 we'll get excited about it too...
1923 <ulink url="http://altusmetrum.org/">web site</ulink> for more news
1924 and information as our family of products evolves!
1929 <title>Altimeter Installation Recommendations</title>
1931 Building high-power rockets that fly safely is hard enough. Mix
1932 in some sophisticated electronics and a bunch of radio energy
1933 and oftentimes you find few perfect solutions. This chapter
1934 contains some suggestions about how to install Altus Metrum
1935 products into the rocket air-frame, including how to safely and
1936 reliably mix a variety of electronics into the same air-frame.
1939 <title>Mounting the Altimeter</title>
1941 The first consideration is to ensure that the altimeter is
1942 securely fastened to the air-frame. For TeleMetrum, we use
1943 nylon standoffs and nylon screws; they're good to at least 50G
1944 and cannot cause any electrical issues on the board. For
1945 TeleMini, we usually cut small pieces of 1/16" balsa to fit
1946 under the screw holes, and then take 2x56 nylon screws and
1947 screw them through the TeleMini mounting holes, through the
1948 balsa and into the underlying material.
1950 <orderedlist inheritnum='inherit' numeration='arabic'>
1952 Make sure TeleMetrum is aligned precisely along the axis of
1953 acceleration so that the accelerometer can accurately
1954 capture data during the flight.
1957 Watch for any metal touching components on the
1958 board. Shorting out connections on the bottom of the board
1959 can cause the altimeter to fail during flight.
1964 <title>Dealing with the Antenna</title>
1966 The antenna supplied is just a piece of solid, insulated,
1967 wire. If it gets damaged or broken, it can be easily
1968 replaced. It should be kept straight and not cut; bending or
1969 cutting it will change the resonant frequency and/or
1970 impedance, making it a less efficient radiator and thus
1971 reducing the range of the telemetry signal.
1974 Keeping metal away from the antenna will provide better range
1975 and a more even radiation pattern. In most rockets, it's not
1976 entirely possible to isolate the antenna from metal
1977 components; there are often bolts, all-thread and wires from other
1978 electronics to contend with. Just be aware that the more stuff
1979 like this around the antenna, the lower the range.
1982 Make sure the antenna is not inside a tube made or covered
1983 with conducting material. Carbon fiber is the most common
1984 culprit here -- CF is a good conductor and will effectively
1985 shield the antenna, dramatically reducing signal strength and
1986 range. Metallic flake paint is another effective shielding
1987 material which is to be avoided around any antennas.
1990 If the ebay is large enough, it can be convenient to simply
1991 mount the altimeter at one end and stretch the antenna out
1992 inside. Taping the antenna to the sled can keep it straight
1993 under acceleration. If there are metal rods, keep the
1994 antenna as far away as possible.
1997 For a shorter ebay, it's quite practical to have the antenna
1998 run through a bulkhead and into an adjacent bay. Drill a small
1999 hole in the bulkhead, pass the antenna wire through it and
2000 then seal it up with glue or clay. We've also used acrylic
2001 tubing to create a cavity for the antenna wire. This works a
2002 bit better in that the antenna is known to stay straight and
2003 not get folded by recovery components in the bay. Angle the
2004 tubing towards the side wall of the rocket and it ends up
2005 consuming very little space.
2008 If you need to place the antenna at a distance from the
2009 altimeter, you can replace the antenna with an edge-mounted
2010 SMA connector, and then run 50Ω coax from the board to the
2011 antenna. Building a remote antenna is beyond the scope of this
2016 <title>Preserving GPS Reception</title>
2018 The GPS antenna and receiver in TeleMetrum are highly
2019 sensitive and normally have no trouble tracking enough
2020 satellites to provide accurate position information for
2021 recovering the rocket. However, there are many ways to
2022 attenuate the GPS signal.
2023 <orderedlist inheritnum='inherit' numeration='arabic'>
2025 Conductive tubing or coatings. Carbon fiber and metal
2026 tubing, or metallic paint will all dramatically attenuate the
2027 GPS signal. We've never heard of anyone successfully
2028 receiving GPS from inside these materials.
2031 Metal components near the GPS patch antenna. These will
2032 de-tune the patch antenna, changing the resonant frequency
2033 away from the L1 carrier and reduce the effectiveness of the
2034 antenna. You can place as much stuff as you like beneath the
2035 antenna as that's covered with a ground plane. But, keep
2036 wires and metal out from above the patch antenna.
2042 <title>Radio Frequency Interference</title>
2044 Any altimeter will generate RFI; the digital circuits use
2045 high-frequency clocks that spray radio interference across a
2046 wide band. Altus Metrum altimeters generate intentional radio
2047 signals as well, increasing the amount of RF energy around the board.
2050 Rocketry altimeters also use precise sensors measuring air
2051 pressure and acceleration. Tiny changes in voltage can cause
2052 these sensor readings to vary by a huge amount. When the
2053 sensors start mis-reporting data, the altimeter can either
2054 fire the igniters at the wrong time, or not fire them at all.
2057 Voltages are induced when radio frequency energy is
2058 transmitted from one circuit to another. Here are things that
2059 influence the induced voltage and current:
2063 Keep wires from different circuits apart. Moving circuits
2064 further apart will reduce RFI.
2067 Avoid parallel wires from different circuits. The longer two
2068 wires run parallel to one another, the larger the amount of
2069 transferred energy. Cross wires at right angles to reduce
2073 Twist wires from the same circuits. Two wires the same
2074 distance from the transmitter will get the same amount of
2075 induced energy which will then cancel out. Any time you have
2076 a wire pair running together, twist the pair together to
2077 even out distances and reduce RFI. For altimeters, this
2078 includes battery leads, switch hookups and igniter
2082 Avoid resonant lengths. Know what frequencies are present
2083 in the environment and avoid having wire lengths near a
2084 natural resonant length. Altusmetrum products transmit on the
2085 70cm amateur band, so you should avoid lengths that are a
2086 simple ratio of that length; essentially any multiple of 1/4
2087 of the wavelength (17.5cm).
2092 <title>The Barometric Sensor</title>
2094 Altusmetrum altimeters measure altitude with a barometric
2095 sensor, essentially measuring the amount of air above the
2096 rocket to figure out how high it is. A large number of
2097 measurements are taken as the altimeter initializes itself to
2098 figure out the pad altitude. Subsequent measurements are then
2099 used to compute the height above the pad.
2102 To accurately measure atmospheric pressure, the ebay
2103 containing the altimeter must be vented outside the
2104 air-frame. The vent must be placed in a region of linear
2105 airflow, have smooth edges, and away from areas of increasing or
2106 decreasing pressure.
2109 The barometric sensor in the altimeter is quite sensitive to
2110 chemical damage from the products of APCP or BP combustion, so
2111 make sure the ebay is carefully sealed from any compartment
2112 which contains ejection charges or motors.
2116 <title>Ground Testing</title>
2118 The most important aspect of any installation is careful
2119 ground testing. Bringing an air-frame up to the LCO table which
2120 hasn't been ground tested can lead to delays or ejection
2121 charges firing on the pad, or, even worse, a recovery system
2125 Do a 'full systems' test that includes wiring up all igniters
2126 without any BP and turning on all of the electronics in flight
2127 mode. This will catch any mistakes in wiring and any residual
2128 RFI issues that might accidentally fire igniters at the wrong
2129 time. Let the air-frame sit for several minutes, checking for
2130 adequate telemetry signal strength and GPS lock. If any igniters
2131 fire unexpectedly, find and resolve the issue before loading any
2135 Ground test the ejection charges. Prepare the rocket for
2136 flight, loading ejection charges and igniters. Completely
2137 assemble the air-frame and then use the 'Fire Igniters'
2138 interface through a TeleDongle to command each charge to
2139 fire. Make sure the charge is sufficient to robustly separate
2140 the air-frame and deploy the recovery system.
2145 <title>Updating Device Firmware</title>
2147 The big concept to understand is that you have to use a
2148 TeleDongle as a programmer to update a TeleMetrum or TeleMini,
2149 and a TeleMetrum or other TeleDongle to program the TeleDongle
2150 Due to limited memory resources in the cc1111, we don't support
2151 programming directly over USB.
2154 You may wish to begin by ensuring you have current firmware images.
2155 These are distributed as part of the AltOS software bundle that
2156 also includes the AltosUI ground station program. Newer ground
2157 station versions typically work fine with older firmware versions,
2158 so you don't need to update your devices just to try out new
2159 software features. You can always download the most recent
2160 version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
2163 We recommend updating the altimeter first, before updating TeleDongle.
2166 <title>Updating TeleMetrum Firmware</title>
2167 <orderedlist inheritnum='inherit' numeration='arabic'>
2169 Find the 'programming cable' that you got as part of the starter
2170 kit, that has a red 8-pin MicroMaTch connector on one end and a
2171 red 4-pin MicroMaTch connector on the other end.
2174 Take the 2 screws out of the TeleDongle case to get access
2175 to the circuit board.
2178 Plug the 8-pin end of the programming cable to the
2179 matching connector on the TeleDongle, and the 4-pin end to the
2180 matching connector on the TeleMetrum.
2181 Note that each MicroMaTch connector has an alignment pin that
2182 goes through a hole in the PC board when you have the cable
2186 Attach a battery to the TeleMetrum board.
2189 Plug the TeleDongle into your computer's USB port, and power
2193 Run AltosUI, and select 'Flash Image' from the File menu.
2196 Pick the TeleDongle device from the list, identifying it as the
2200 Select the image you want put on the TeleMetrum, which should have a
2201 name in the form telemetrum-v1.2-1.0.0.ihx. It should be visible
2202 in the default directory, if not you may have to poke around
2203 your system to find it.
2206 Make sure the configuration parameters are reasonable
2207 looking. If the serial number and/or RF configuration
2208 values aren't right, you'll need to change them.
2211 Hit the 'OK' button and the software should proceed to flash
2212 the TeleMetrum with new firmware, showing a progress bar.
2215 Confirm that the TeleMetrum board seems to have updated OK, which you
2216 can do by plugging in to it over USB and using a terminal program
2217 to connect to the board and issue the 'v' command to check
2221 If something goes wrong, give it another try.
2226 <title>Updating TeleMini Firmware</title>
2227 <orderedlist inheritnum='inherit' numeration='arabic'>
2229 You'll need a special 'programming cable' to reprogram the
2230 TeleMini. It's available on the Altus Metrum web store, or
2231 you can make your own using an 8-pin MicroMaTch connector on
2232 one end and a set of four pins on the other.
2235 Take the 2 screws out of the TeleDongle case to get access
2236 to the circuit board.
2239 Plug the 8-pin end of the programming cable to the matching
2240 connector on the TeleDongle, and the 4-pins into the holes
2241 in the TeleMini circuit board. Note that the MicroMaTch
2242 connector has an alignment pin that goes through a hole in
2243 the PC board when you have the cable oriented correctly, and
2244 that pin 1 on the TeleMini board is marked with a square pad
2245 while the other pins have round pads.
2248 Attach a battery to the TeleMini board.
2251 Plug the TeleDongle into your computer's USB port, and power
2255 Run AltosUI, and select 'Flash Image' from the File menu.
2258 Pick the TeleDongle device from the list, identifying it as the
2262 Select the image you want put on the TeleMini, which should have a
2263 name in the form telemini-v1.0-1.0.0.ihx. It should be visible
2264 in the default directory, if not you may have to poke around
2265 your system to find it.
2268 Make sure the configuration parameters are reasonable
2269 looking. If the serial number and/or RF configuration
2270 values aren't right, you'll need to change them.
2273 Hit the 'OK' button and the software should proceed to flash
2274 the TeleMini with new firmware, showing a progress bar.
2277 Confirm that the TeleMini board seems to have updated OK, which you
2278 can do by configuring it over the radio link through the TeleDongle, or
2279 letting it come up in "flight" mode and listening for telemetry.
2282 If something goes wrong, give it another try.
2287 <title>Updating TeleDongle Firmware</title>
2289 Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
2290 firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
2292 <orderedlist inheritnum='inherit' numeration='arabic'>
2294 Find the 'programming cable' that you got as part of the starter
2295 kit, that has a red 8-pin MicroMaTch connector on one end and a
2296 red 4-pin MicroMaTch connector on the other end.
2299 Find the USB cable that you got as part of the starter kit, and
2300 plug the "mini" end in to the mating connector on TeleMetrum or TeleDongle.
2303 Take the 2 screws out of the TeleDongle case to get access
2304 to the circuit board.
2307 Plug the 8-pin end of the programming cable to the
2308 matching connector on the programmer, and the 4-pin end to the
2309 matching connector on the TeleDongle.
2310 Note that each MicroMaTch connector has an alignment pin that
2311 goes through a hole in the PC board when you have the cable
2315 Attach a battery to the TeleMetrum board if you're using one.
2318 Plug both the programmer and the TeleDongle into your computer's USB
2319 ports, and power up the programmer.
2322 Run AltosUI, and select 'Flash Image' from the File menu.
2325 Pick the programmer device from the list, identifying it as the
2329 Select the image you want put on the TeleDongle, which should have a
2330 name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
2331 in the default directory, if not you may have to poke around
2332 your system to find it.
2335 Make sure the configuration parameters are reasonable
2336 looking. If the serial number and/or RF configuration
2337 values aren't right, you'll need to change them. The TeleDongle
2338 serial number is on the "bottom" of the circuit board, and can
2339 usually be read through the translucent blue plastic case without
2340 needing to remove the board from the case.
2343 Hit the 'OK' button and the software should proceed to flash
2344 the TeleDongle with new firmware, showing a progress bar.
2347 Confirm that the TeleDongle board seems to have updated OK, which you
2348 can do by plugging in to it over USB and using a terminal program
2349 to connect to the board and issue the 'v' command to check
2350 the version, etc. Once you're happy, remove the programming cable
2351 and put the cover back on the TeleDongle.
2354 If something goes wrong, give it another try.
2358 Be careful removing the programming cable from the locking 8-pin
2359 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
2360 screwdriver or knife blade to gently pry the locking ears out
2361 slightly to extract the connector. We used a locking connector on
2362 TeleMetrum to help ensure that the cabling to companion boards
2363 used in a rocket don't ever come loose accidentally in flight.
2368 <title>Hardware Specifications</title>
2370 <title>TeleMetrum Specifications</title>
2374 Recording altimeter for model rocketry.
2379 Supports dual deployment (can fire 2 ejection charges).
2384 70cm ham-band transceiver for telemetry down-link.
2389 Barometric pressure sensor good to 45k feet MSL.
2394 1-axis high-g accelerometer for motor characterization, capable of
2395 +/- 50g using default part.
2400 On-board, integrated GPS receiver with 5Hz update rate capability.
2405 On-board 1 megabyte non-volatile memory for flight data storage.
2410 USB interface for battery charging, configuration, and data recovery.
2415 Fully integrated support for Li-Po rechargeable batteries.
2420 Uses Li-Po to fire e-matches, can be modified to support
2421 optional separate pyro battery if needed.
2426 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
2432 <title>TeleMini Specifications</title>
2436 Recording altimeter for model rocketry.
2441 Supports dual deployment (can fire 2 ejection charges).
2446 70cm ham-band transceiver for telemetry down-link.
2451 Barometric pressure sensor good to 45k feet MSL.
2456 On-board 5 kilobyte non-volatile memory for flight data storage.
2461 RF interface for configuration, and data recovery.
2466 Support for Li-Po rechargeable batteries, using an external charger.
2471 Uses Li-Po to fire e-matches, can be modified to support
2472 optional separate pyro battery if needed.
2477 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube.
2486 TeleMetrum seems to shut off when disconnected from the
2487 computer. Make sure the battery is adequately charged. Remember the
2488 unit will pull more power than the USB port can deliver before the
2489 GPS enters "locked" mode. The battery charges best when TeleMetrum
2493 It's impossible to stop the TeleDongle when it's in "p" mode, I have
2494 to unplug the USB cable? Make sure you have tried to "escape out" of
2495 this mode. If this doesn't work the reboot procedure for the
2496 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
2497 outgoing buffer IF your "escape out" ('~~') does not work.
2498 At this point using either 'ao-view' (or possibly
2499 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
2503 The amber LED (on the TeleMetrum) lights up when both
2504 battery and USB are connected. Does this mean it's charging?
2505 Yes, the yellow LED indicates the charging at the 'regular' rate.
2506 If the led is out but the unit is still plugged into a USB port,
2507 then the battery is being charged at a 'trickle' rate.
2510 There are no "dit-dah-dah-dit" sound or lights like the manual mentions?
2511 That's the "pad" mode. Weak batteries might be the problem.
2512 It is also possible that the TeleMetrum is horizontal and the output
2513 is instead a "dit-dit" meaning 'idle'. For TeleMini, it's possible that
2514 it received a command packet which would have left it in "pad" mode.
2517 How do I save flight data?
2518 Live telemetry is written to file(s) whenever AltosUI is connected
2519 to the TeleDongle. The file area defaults to ~/TeleMetrum
2520 but is easily changed using the menus in AltosUI. The files that
2521 are written end in '.telem'. The after-flight
2522 data-dumped files will end in .eeprom and represent continuous data
2523 unlike the .telem files that are subject to losses
2524 along the RF data path.
2525 See the above instructions on what and how to save the eeprom stored
2526 data after physically retrieving your altimeter. Make sure to save
2527 the on-board data after each flight; while the TeleMetrum can store
2528 multiple flights, you never know when you'll lose the altimeter...
2532 <title>Notes for Older Software</title>
2535 Before AltosUI was written, using Altus Metrum devices required
2536 some finesse with the Linux command line. There was a limited
2537 GUI tool, ao-view, which provided functionality similar to the
2538 Monitor Flight window in AltosUI, but everything else was a
2539 fairly 80's experience. This appendix includes documentation for
2540 using that software.
2544 Both TeleMetrum and TeleDongle can be directly communicated
2545 with using USB ports. The first thing you should try after getting
2546 both units plugged into to your computer's USB port(s) is to run
2547 'ao-list' from a terminal-window to see what port-device-name each
2548 device has been assigned by the operating system.
2549 You will need this information to access the devices via their
2550 respective on-board firmware and data using other command line
2551 programs in the AltOS software suite.
2554 TeleMini can be communicated with through a TeleDongle device
2555 over the radio link. When first booted, TeleMini listens for a
2556 TeleDongle device and if it receives a packet, it goes into
2557 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be
2558 launched. The easiest way to get it talking is to start the
2559 communication link on the TeleDongle and the power up the
2563 To access the device's firmware for configuration you need a terminal
2564 program such as you would use to talk to a modem. The software
2565 authors prefer using the program 'cu' which comes from the UUCP package
2566 on most Unix-like systems such as Linux. An example command line for
2567 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
2568 indicated from running the
2569 ao-list program. Another reasonable terminal program for Linux is
2570 'cutecom'. The default 'escape'
2571 character used by CU (i.e. the character you use to
2572 issue commands to cu itself instead of sending the command as input
2573 to the connected device) is a '~'. You will need this for use in
2574 only two different ways during normal operations. First is to exit
2575 the program by sending a '~.' which is called a 'escape-disconnect'
2576 and allows you to close-out from 'cu'. The
2577 second use will be outlined later.
2580 All of the Altus Metrum devices share the concept of a two level
2581 command set in their firmware.
2582 The first layer has several single letter commands. Once
2583 you are using 'cu' (or 'cutecom') sending (typing) a '?'
2584 returns a full list of these
2585 commands. The second level are configuration sub-commands accessed
2586 using the 'c' command, for
2587 instance typing 'c?' will give you this second level of commands
2588 (all of which require the
2589 letter 'c' to access). Please note that most configuration options
2590 are stored only in Flash memory; TeleDongle doesn't provide any storage
2591 for these options and so they'll all be lost when you unplug it.
2594 Try setting these configuration ('c' or second level menu) values. A good
2595 place to start is by setting your call sign. By default, the boards
2596 use 'N0CALL' which is cute, but not exactly legal!
2597 Spend a few minutes getting comfortable with the units, their
2598 firmware, and 'cu' (or possibly 'cutecom').
2599 For instance, try to send
2600 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
2601 Verify you can connect and disconnect from the units while in your
2602 terminal program by sending the escape-disconnect mentioned above.
2605 To set the radio frequency, use the 'c R' command to specify the
2606 radio transceiver configuration parameter. This parameter is computed
2607 using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
2608 the standard calibration reference frequency, 'S', (normally 434.550MHz):
2612 Round the result to the nearest integer value.
2613 As with all 'c' sub-commands, follow this with a 'c w' to write the
2614 change to the parameter block in the on-board flash on
2615 your altimeter board if you want the change to stay in place across reboots.
2618 To set the apogee delay, use the 'c d' command.
2619 As with all 'c' sub-commands, follow this with a 'c w' to write the
2620 change to the parameter block in the on-board DataFlash chip.
2623 To set the main deployment altitude, use the 'c m' command.
2624 As with all 'c' sub-commands, follow this with a 'c w' to write the
2625 change to the parameter block in the on-board DataFlash chip.
2628 To calibrate the radio frequency, connect the UHF antenna port to a
2629 frequency counter, set the board to 434.550MHz, and use the 'C'
2630 command to generate a CW carrier. Wait for the transmitter temperature
2631 to stabilize and the frequency to settle down.
2632 Then, divide 434.550 MHz by the
2633 measured frequency and multiply by the current radio cal value show
2634 in the 'c s' command. For an unprogrammed board, the default value
2635 is 1186611. Take the resulting integer and program it using the 'c f'
2636 command. Testing with the 'C' command again should show a carrier
2637 within a few tens of Hertz of the intended frequency.
2638 As with all 'c' sub-commands, follow this with a 'c w' to write the
2639 change to the parameter block in the on-board DataFlash chip.
2642 Note that the 'reboot' command, which is very useful on the altimeters,
2643 will likely just cause problems with the dongle. The *correct* way
2644 to reset the dongle is just to unplug and re-plug it.
2647 A fun thing to do at the launch site and something you can do while
2648 learning how to use these units is to play with the radio link access
2649 between an altimeter and the TeleDongle. Be aware that you *must* create
2650 some physical separation between the devices, otherwise the link will
2651 not function due to signal overload in the receivers in each device.
2654 Now might be a good time to take a break and read the rest of this
2655 manual, particularly about the two "modes" that the altimeters
2656 can be placed in. TeleMetrum uses the position of the device when booting
2657 up will determine whether the unit is in "pad" or "idle" mode. TeleMini
2658 enters "idle" mode when it receives a command packet within the first 5 seconds
2659 of being powered up, otherwise it enters "pad" mode.
2662 You can access an altimeter in idle mode from the TeleDongle's USB
2663 connection using the radio link
2664 by issuing a 'p' command to the TeleDongle. Practice connecting and
2665 disconnecting ('~~' while using 'cu') from the altimeter. If
2666 you cannot escape out of the "p" command, (by using a '~~' when in
2667 CU) then it is likely that your kernel has issues. Try a newer version.
2670 Using this radio link allows you to configure the altimeter, test
2671 fire e-matches and igniters from the flight line, check pyro-match
2672 continuity and so forth. You can leave the unit turned on while it
2673 is in 'idle mode' and then place the
2674 rocket vertically on the launch pad, walk away and then issue a
2675 reboot command. The altimeter will reboot and start sending data
2676 having changed to the "pad" mode. If the TeleDongle is not receiving
2677 this data, you can disconnect 'cu' from the TeleDongle using the
2678 procedures mentioned above and THEN connect to the TeleDongle from
2679 inside 'ao-view'. If this doesn't work, disconnect from the
2680 TeleDongle, unplug it, and try again after plugging it back in.
2683 In order to reduce the chance of accidental firing of pyrotechnic
2684 charges, the command to fire a charge is intentionally somewhat
2685 difficult to type, and the built-in help is slightly cryptic to
2686 prevent accidental echoing of characters from the help text back at
2687 the board from firing a charge. The command to fire the apogee
2688 drogue charge is 'i DoIt drogue' and the command to fire the main
2689 charge is 'i DoIt main'.
2692 On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
2693 and 'ao-view' will both auditorily announce and visually indicate
2695 Now you can launch knowing that you have a good data path and
2696 good satellite lock for flight data and recovery. Remember
2697 you MUST tell ao-view to connect to the TeleDongle explicitly in
2698 order for ao-view to be able to receive data.
2701 The altimeters provide RDF (radio direction finding) tones on
2702 the pad, during descent and after landing. These can be used to
2703 locate the rocket using a directional antenna; the signal
2704 strength providing an indication of the direction from receiver to rocket.
2707 TeleMetrum also provides GPS tracking data, which can further simplify
2708 locating the rocket once it has landed. (The last good GPS data
2709 received before touch-down will be on the data screen of 'ao-view'.)
2712 Once you have recovered the rocket you can download the eeprom
2713 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
2714 either a USB cable or over the radio link using TeleDongle.
2715 And by following the man page for 'ao-postflight' you can create
2716 various data output reports, graphs, and even KML data to see the
2717 flight trajectory in Google-earth. (Moving the viewing angle making
2718 sure to connect the yellow lines while in Google-earth is the proper
2722 As for ao-view.... some things are in the menu but don't do anything
2723 very useful. The developers have stopped working on ao-view to focus
2724 on a new, cross-platform ground station program. So ao-view may or
2725 may not be updated in the future. Mostly you just use
2726 the Log and Device menus. It has a wonderful display of the incoming
2727 flight data and I am sure you will enjoy what it has to say to you
2728 once you enable the voice output!
2732 <title>Drill Templates</title>
2734 These images, when printed, provide precise templates for the
2735 mounting holes in Altus Metrum flight computers
2738 <title>TeleMetrum template</title>
2740 TeleMetrum has overall dimensions of 1.000 x 2.750 inches, and the
2741 mounting holes are sized for use with 4-40 or M3 screws.
2743 <mediaobject id="TeleMetrumTemplate">
2745 <imagedata format="SVG" fileref="telemetrum.svg"/>
2750 <title>TeleMini template</title>
2752 TeleMini has overall dimensions of 0.500 x 1.500 inches, and the
2753 mounting holes are sized for use with 2-56 or M2 screws.
2755 <mediaobject id="TeleMiniTemplate">
2757 <imagedata format="SVG" fileref="telemini.svg"/>
2763 <title>Calibration</title>
2765 There are only two calibrations required for a TeleMetrum board, and
2766 only one for TeleDongle and TeleMini. All boards are shipped from
2767 the factory pre-calibrated, but the procedures are documented here
2768 in case they are ever needed. Re-calibration is not supported by
2769 AltosUI, you must connect to the board with a serial terminal program
2770 and interact directly with the on-board command interpreter to effect
2774 <title>Radio Frequency</title>
2776 The radio frequency is synthesized from a clock based on the 48 MHz
2777 crystal on the board. The actual frequency of this oscillator
2778 must be measured to generate a calibration constant. While our
2780 bandwidth is wide enough to allow boards to communicate even when
2781 their oscillators are not on exactly the same frequency, performance
2782 is best when they are closely matched.
2783 Radio frequency calibration requires a calibrated frequency counter.
2784 Fortunately, once set, the variation in frequency due to aging and
2785 temperature changes is small enough that re-calibration by customers
2786 should generally not be required.
2789 To calibrate the radio frequency, connect the UHF antenna port to a
2790 frequency counter, set the board to 434.550MHz, and use the 'C'
2791 command in the on-board command interpreter to generate a CW
2792 carrier. For TeleMetrum, this is best done over USB. For TeleMini,
2793 note that the only way to escape the 'C' command is via power cycle
2794 since the board will no longer be listening for commands once it
2795 starts generating a CW carrier.
2798 Wait for the transmitter temperature to stabilize and the frequency
2799 to settle down. Then, divide 434.550 MHz by the
2800 measured frequency and multiply by the current radio cal value show
2801 in the 'c s' command. For an unprogrammed board, the default value
2802 is 1186611. Take the resulting integer and program it using the 'c f'
2803 command. Testing with the 'C' command again should show a carrier
2804 within a few tens of Hertz of the intended frequency.
2805 As with all 'c' sub-commands, follow this with a 'c w' to write the
2806 change to the parameter block in the on-board DataFlash chip.
2809 Note that any time you re-do the radio frequency calibration, the
2810 radio frequency is reset to the default 434.550 Mhz. If you want
2811 to use another frequency, you will have to set that again after
2812 calibration is completed.
2816 <title>TeleMetrum Accelerometer</title>
2818 The TeleMetrum accelerometer we use has its own 5 volt power
2820 the output must be passed through a resistive voltage divider to match
2821 the input of our 3.3 volt ADC. This means that unlike the barometric
2822 sensor, the output of the acceleration sensor is not ratio-metric to
2823 the ADC converter, and calibration is required. Explicitly
2824 calibrating the accelerometers also allows us to load any device
2825 from a Freescale family that includes at least +/- 40g, 50g, 100g,
2826 and 200g parts. Using gravity,
2827 a simple 2-point calibration yields acceptable results capturing both
2828 the different sensitivities and ranges of the different accelerometer
2829 parts and any variation in power supply voltages or resistor values
2830 in the divider network.
2833 To calibrate the acceleration sensor, use the 'c a 0' command. You
2834 will be prompted to orient the board vertically with the UHF antenna
2835 up and press a key, then to orient the board vertically with the
2836 UHF antenna down and press a key. Note that the accuracy of this
2837 calibration depends primarily on how perfectly vertical and still
2838 the board is held during the cal process. As with all 'c'
2839 sub-commands, follow this with a 'c w' to write the
2840 change to the parameter block in the on-board DataFlash chip.
2843 The +1g and -1g calibration points are included in each telemetry
2844 frame and are part of the header stored in onboard flash to be
2845 downloaded after flight. We always store and return raw ADC
2846 samples for each sensor... so nothing is permanently "lost" or
2847 "damaged" if the calibration is poor.
2850 In the unlikely event an accel cal goes badly, it is possible
2851 that TeleMetrum may always come up in 'pad mode' and as such not be
2852 listening to either the USB or radio link. If that happens,
2853 there is a special hook in the firmware to force the board back
2854 in to 'idle mode' so you can re-do the cal. To use this hook, you
2855 just need to ground the SPI clock pin at power-on. This pin is
2856 available as pin 2 on the 8-pin companion connector, and pin 1 is
2857 ground. So either carefully install a fine-gauge wire jumper
2858 between the two pins closest to the index hole end of the 8-pin
2859 connector, or plug in the programming cable to the 8-pin connector
2860 and use a small screwdriver or similar to short the two pins closest
2861 to the index post on the 4-pin end of the programming cable, and
2862 power up the board. It should come up in 'idle mode' (two beeps),
2868 xmlns:xi="http://www.w3.org/2001/XInclude">
2869 <title>Release Notes</title>
2870 <simplesect><title>Version 1.21</title><xi:include href="release-notes-1.2.1.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2871 <simplesect><title>Version 1.2</title><xi:include href="release-notes-1.2.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2872 <simplesect><title>Version 1.1.1</title><xi:include href="release-notes-1.1.1.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2873 <simplesect><title>Version 1.1</title><xi:include href="release-notes-1.1.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2874 <simplesect><title>Version 1.0.1</title><xi:include href="release-notes-1.0.1.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2875 <simplesect><title>Version 0.9.2</title><xi:include href="release-notes-0.9.2.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2876 <simplesect><title>Version 0.9</title><xi:include href="release-notes-0.9.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2877 <simplesect><title>Version 0.8</title><xi:include href="release-notes-0.8.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2878 <simplesect><title>Version 0.7.1</title><xi:include href="release-notes-0.7.1.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2882 <!-- LocalWords: Altusmetrum
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