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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</revnumber>
40 <date>14 April 2013</date>
42 Updated for software version 1.2. Version 1.2 adds support
43 for TeleBT and AltosDroid. It also adds a few minor features
44 and fixes a few minor bugs in AltosUI and the AltOS firmware.
48 <revnumber>1.1.1</revnumber>
49 <date>16 September 2012</date>
51 Updated for software version 1.1.1 Version 1.1.1 fixes a few
52 bugs found in version 1.1.
56 <revnumber>1.1</revnumber>
57 <date>13 September 2012</date>
59 Updated for software version 1.1. Version 1.1 has new
60 features but is otherwise compatible with version 1.0.
64 <revnumber>1.0</revnumber>
65 <date>24 August 2011</date>
67 Updated for software version 1.0. Note that 1.0 represents a
68 telemetry format change, meaning both ends of a link
69 (TeleMetrum/TeleMini and TeleDongle) must be updated or
70 communications will fail.
74 <revnumber>0.9</revnumber>
75 <date>18 January 2011</date>
77 Updated for software version 0.9. Note that 0.9 represents a
78 telemetry format change, meaning both ends of a link (TeleMetrum and
79 TeleDongle) must be updated or communications will fail.
83 <revnumber>0.8</revnumber>
84 <date>24 November 2010</date>
85 <revremark>Updated for software version 0.8 </revremark>
91 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing "The
92 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
93 Kit" which formed the basis of the original Getting Started chapter
94 in this manual. Bob was one of our first customers for a production
95 TeleMetrum, and his continued enthusiasm and contributions
96 are immensely gratifying and highly appreciated!
99 And thanks to Anthony (AJ) Towns for major contributions including
100 the AltosUI graphing and site map code and associated documentation.
101 Free software means that our customers and friends can become our
102 collaborators, and we certainly appreciate this level of
106 Have fun using these products, and we hope to meet all of you
107 out on the rocket flight line somewhere.
110 NAR #87103, TRA #12201
112 Keith Packard, KD7SQG
113 NAR #88757, TRA #12200
118 <title>Introduction and Overview</title>
120 Welcome to the Altus Metrum community! Our circuits and software reflect
121 our passion for both hobby rocketry and Free Software. We hope their
122 capabilities and performance will delight you in every way, but by
123 releasing all of our hardware and software designs under open licenses,
124 we also hope to empower you to take as active a role in our collective
128 The first device created for our community was TeleMetrum, a dual
129 deploy altimeter with fully integrated GPS and radio telemetry
130 as standard features, and a "companion interface" that will
131 support optional capabilities in the future.
134 Our second device was TeleMini, a dual deploy altimeter with
135 radio telemetry and radio direction finding. This device is only
136 13mm by 38mm (½ inch by 1½ inches) and can fit easily in an 18mm
140 TeleDongle was our first ground station, providing a USB to RF
141 interfaces for communicating with the altimeters. Combined with
142 your choice of antenna and notebook computer, TeleDongle and our
143 associated user interface software form a complete ground
144 station capable of logging and displaying in-flight telemetry,
145 aiding rocket recovery, then processing and archiving flight
146 data for analysis and review.
149 For a slightly more portable ground station experience that also
150 provides direct rocket recovery support, TeleBT offers flight
151 monitoring and data logging using a Bluetooth connection between
152 the receiver and an Android device that has the Altos Droid
153 application installed from the Google Play store.
156 More products will be added to the Altus Metrum family over time, and
157 we currently envision that this will be a single, comprehensive manual
158 for the entire product family.
162 <title>Getting Started</title>
164 The first thing to do after you check the inventory of parts in your
165 "starter kit" is to charge the battery.
168 The TeleMetrum battery can be charged by plugging it into the
169 corresponding socket of the TeleMetrum and then using the USB A to
171 cable to plug the TeleMetrum into your computer's USB socket. The
172 TeleMetrum circuitry will charge the battery whenever it is plugged
173 in, because the TeleMetrum's on-off switch does NOT control the
177 When the GPS chip is initially searching for
178 satellites, TeleMetrum will consume more current than it can pull
179 from the USB port, so the battery must be attached in order to get
180 satellite lock. Once GPS is locked, the current consumption goes back
181 down enough to enable charging while
182 running. So it's a good idea to fully charge the battery as your
183 first item of business so there is no issue getting and maintaining
184 satellite lock. The yellow charge indicator led will go out when the
185 battery is nearly full and the charger goes to trickle charge. It
186 can take several hours to fully recharge a deeply discharged battery.
189 The TeleMini battery can be charged by disconnecting it from the
190 TeleMini board and plugging it into a standalone battery charger
191 such as the LipoCharger product included in TeleMini Starter Kits,
192 and connecting that via a USB cable to a laptop or other USB
196 The other active device in the starter kit is the TeleDongle USB to
197 RF interface. If you plug it in to your Mac or Linux computer it should
198 "just work", showing up as a serial port device. Windows systems need
199 driver information that is part of the AltOS download to know that the
200 existing USB modem driver will work. We therefore recommend installing
201 our software before plugging in TeleDongle if you are using a Windows
202 computer. If you are using Linux and are having problems, try moving
203 to a fresher kernel (2.6.33 or newer), as the USB serial driver had
204 ugly bugs in some earlier versions.
207 Next you should obtain and install the AltOS software. These include
208 the AltosUI ground station program, current firmware images for
209 TeleMetrum, TeleMini and TeleDongle, and a number of standalone
210 utilities that are rarely needed. Pre-built binary packages are
211 available for Linux, Microsoft Windows, and recent MacOSX versions.
212 Full source code and build instructions are also available.
213 The latest version may always be downloaded from
214 <ulink url="http://altusmetrum.org/AltOS"/>.
217 If you're using a TeleBT instead of the TeleDongle, you'll want
218 to go install the Altos Droid application from the Google Play
219 store. You don't need a data plan to use Altos Droid, but
220 without network access, the Map view will be less useful as it
221 won't contain any map data. You can also use TeleBT connected
222 over USB with your laptop computer; it acts exactly like a
223 TeleDongle. Anywhere this manual talks about TeleDongle, you can
224 also read that as 'and TeleBT when connected via USB'.
228 <title>Handling Precautions</title>
230 All Altus Metrum products are sophisticated electronic devices.
231 When handled gently and properly installed in an air-frame, they
232 will deliver impressive results. However, as with all electronic
233 devices, there are some precautions you must take.
236 The Lithium Polymer rechargeable batteries have an
237 extraordinary power density. This is great because we can fly with
238 much less battery mass than if we used alkaline batteries or previous
239 generation rechargeable batteries... but if they are punctured
240 or their leads are allowed to short, they can and will release their
242 Thus we recommend that you take some care when handling our batteries
243 and consider giving them some extra protection in your air-frame. We
244 often wrap them in suitable scraps of closed-cell packing foam before
245 strapping them down, for example.
248 The barometric sensors used on both TeleMetrum and TeleMini are
249 sensitive to sunlight. In normal TeleMetrum mounting situations, it
250 and all of the other surface mount components
251 are "down" towards whatever the underlying mounting surface is, so
252 this is not normally a problem. Please consider this, though, when
253 designing an installation, for example, in an air-frame with a
254 see-through plastic payload bay. It is particularly important to
255 consider this with TeleMini, both because the baro sensor is on the
256 "top" of the board, and because many model rockets with payload bays
257 use clear plastic for the payload bay! Replacing these with an opaque
258 cardboard tube, painting them, or wrapping them with a layer of masking
259 tape are all reasonable approaches to keep the sensor out of direct
263 The barometric sensor sampling port must be able to "breathe",
264 both by not being covered by foam or tape or other materials that might
265 directly block the hole on the top of the sensor, and also by having a
266 suitable static vent to outside air.
269 As with all other rocketry electronics, Altus Metrum altimeters must
270 be protected from exposure to corrosive motor exhaust and ejection
275 <title>Hardware Overview</title>
277 TeleMetrum is a 1 inch by 2.75 inch circuit board. It was designed to
278 fit inside coupler for 29mm air-frame tubing, but using it in a tube that
279 small in diameter may require some creativity in mounting and wiring
280 to succeed! The presence of an accelerometer means TeleMetrum should
281 be aligned along the flight axis of the airframe, and by default the 1/4
282 wave UHF wire antenna should be on the nose-cone end of the board. The
283 antenna wire is about 7 inches long, and wiring for a power switch and
284 the e-matches for apogee and main ejection charges depart from the
285 fin can end of the board, meaning an ideal "simple" avionics
286 bay for TeleMetrum should have at least 10 inches of interior length.
289 TeleMini is a 0.5 inch by 1.5 inch circuit board. It was designed to
290 fit inside an 18mm air-frame tube, but using it in a tube that
291 small in diameter may require some creativity in mounting and wiring
292 to succeed! Since there is no accelerometer, TeleMini can be mounted
293 in any convenient orientation. The default 1/4
294 wave UHF wire antenna attached to the center of one end of
295 the board is about 7 inches long, and wiring for a power switch and
296 the e-matches for apogee and main ejection charges depart from the
297 other end of the board, meaning an ideal "simple" avionics
298 bay for TeleMini should have at least 9 inches of interior length.
301 A typical TeleMetrum or TeleMini installation involves attaching
302 only a suitable Lithium Polymer battery, a single pole switch for
303 power on/off, and two pairs of wires connecting e-matches for the
304 apogee and main ejection charges. All Altus Metrum products are
305 designed for use with single-cell batteries with 3.7 volts nominal.
308 The battery connectors are a standard 2-pin JST connector and
309 match batteries sold by Spark Fun. These batteries are
310 single-cell Lithium Polymer batteries that nominally provide 3.7
311 volts. Other vendors sell similar batteries for RC aircraft
312 using mating connectors, however the polarity for those is
313 generally reversed from the batteries used by Altus Metrum
314 products. In particular, the Tenergy batteries supplied for use
315 in Featherweight flight computers are not compatible with Altus
316 Metrum flight computers or battery chargers. <emphasis>Check
317 polarity and voltage before connecting any battery not purchased
318 from Altus Metrum or Spark Fun.</emphasis>
321 By default, we use the unregulated output of the Li-Po battery directly
322 to fire ejection charges. This works marvelously with standard
323 low-current e-matches like the J-Tek from MJG Technologies, and with
324 Quest Q2G2 igniters. However, if you want or need to use a separate
325 pyro battery, check out the "External Pyro Battery" section in this
326 manual for instructions on how to wire that up. The altimeters are
327 designed to work with an external pyro battery of no more than 15 volts.
330 Ejection charges are wired directly to the screw terminal block
331 at the aft end of the altimeter. You'll need a very small straight
332 blade screwdriver for these screws, such as you might find in a
333 jeweler's screwdriver set.
336 TeleMetrum also uses the screw terminal block for the power
337 switch leads. On TeleMini, the power switch leads are soldered
338 directly to the board and can be connected directly to a switch.
341 For most air-frames, the integrated antennas are more than
342 adequate. However, if you are installing in a carbon-fiber or
343 metal electronics bay which is opaque to RF signals, you may need to
344 use off-board external antennas instead. In this case, you can
345 order an altimeter with an SMA connector for the UHF antenna
346 connection, and, on TeleMetrum, you can unplug the integrated GPS
347 antenna and select an appropriate off-board GPS antenna with
348 cable terminating in a U.FL connector.
352 <title>System Operation</title>
354 <title>Firmware Modes </title>
356 The AltOS firmware build for the altimeters has two
357 fundamental modes, "idle" and "flight". Which of these modes
358 the firmware operates in is determined at start up time. For
359 TeleMetrum, the mode is controlled by the orientation of the
360 rocket (well, actually the board, of course...) at the time
361 power is switched on. If the rocket is "nose up", then
362 TeleMetrum assumes it's on a rail or rod being prepared for
363 launch, so the firmware chooses flight mode. However, if the
364 rocket is more or less horizontal, the firmware instead enters
365 idle mode. Since TeleMini doesn't have an accelerometer we can
366 use to determine orientation, "idle" mode is selected when the
367 board receives a command packet within the first five seconds
368 of operation; if no packet is received, the board enters
372 At power on, you will hear three beeps or see three flashes
373 ("S" in Morse code for start up) and then a pause while
374 the altimeter completes initialization and self test, and decides
375 which mode to enter next.
378 In flight or "pad" mode, the altimeter engages the flight
379 state machine, goes into transmit-only mode to
380 send telemetry, and waits for launch to be detected.
381 Flight mode is indicated by an "di-dah-dah-dit" ("P" for pad)
382 on the beeper or lights, followed by beeps or flashes
383 indicating the state of the pyrotechnic igniter continuity.
384 One beep/flash indicates apogee continuity, two beeps/flashes
385 indicate main continuity, three beeps/flashes indicate both
386 apogee and main continuity, and one longer "brap" sound or
387 rapidly alternating lights indicates no continuity. For a
388 dual deploy flight, make sure you're getting three beeps or
389 flashes before launching! For apogee-only or motor eject
390 flights, do what makes sense.
393 If idle mode is entered, you will hear an audible "di-dit" or
394 see two short flashes ("I" for idle), and the flight state
395 machine is disengaged, thus no ejection charges will fire.
396 The altimeters also listen for the radio link when in idle
397 mode for requests sent via TeleDongle. Commands can be issued
398 to a TeleMetrum in idle mode over either USB or the radio link
399 equivalently. TeleMini only has the radio link. Idle mode is
400 useful for configuring the altimeter, for extracting data from
401 the on-board storage chip after flight, and for ground testing
405 One "neat trick" of particular value when TeleMetrum is used with
406 very large air-frames, is that you can power the board up while the
407 rocket is horizontal, such that it comes up in idle mode. Then you can
408 raise the air-frame to launch position, and issue a 'reset' command
409 via TeleDongle over the radio link to cause the altimeter to reboot and
410 come up in flight mode. This is much safer than standing on the top
411 step of a rickety step-ladder or hanging off the side of a launch
412 tower with a screw-driver trying to turn on your avionics before
416 TeleMini is configured via the radio link. Of course, that
417 means you need to know the TeleMini radio configuration values
418 or you won't be able to communicate with it. For situations
419 when you don't have the radio configuration values, TeleMini
420 offers an 'emergency recovery' mode. In this mode, TeleMini is
421 configured as follows:
424 Sets the radio frequency to 434.550MHz
427 Sets the radio calibration back to the factory value.
430 Sets the callsign to N0CALL
433 Does not go to 'pad' mode after five seconds.
438 To get into 'emergency recovery' mode, first find the row of
439 four small holes opposite the switch wiring. Using a short
440 piece of small gauge wire, connect the outer two holes
441 together, then power TeleMini up. Once the red LED is lit,
442 disconnect the wire and the board should signal that it's in
443 'idle' mode after the initial five second startup period.
449 TeleMetrum includes a complete GPS receiver. A complete explanation
450 of how GPS works is beyond the scope of this manual, but the bottom
451 line is that the TeleMetrum GPS receiver needs to lock onto at least
452 four satellites to obtain a solid 3 dimensional position fix and know
456 TeleMetrum provides backup power to the GPS chip any time a
457 battery is connected. This allows the receiver to "warm start" on
458 the launch rail much faster than if every power-on were a GPS
459 "cold start". In typical operations, powering up TeleMetrum
460 on the flight line in idle mode while performing final air-frame
461 preparation will be sufficient to allow the GPS receiver to cold
462 start and acquire lock. Then the board can be powered down during
463 RSO review and installation on a launch rod or rail. When the board
464 is turned back on, the GPS system should lock very quickly, typically
465 long before igniter installation and return to the flight line are
470 <title>Controlling An Altimeter Over The Radio Link</title>
472 One of the unique features of the Altus Metrum system is the
473 ability to create a two way command link between TeleDongle
474 and an altimeter using the digital radio transceivers
475 built into each device. This allows you to interact with the
476 altimeter from afar, as if it were directly connected to the
480 Any operation which can be performed with TeleMetrum can
481 either be done with TeleMetrum directly connected to the
482 computer via the USB cable, or through the radio
483 link. TeleMini doesn't provide a USB connector and so it is
484 always communicated with over radio. Select the appropriate
485 TeleDongle device when the list of devices is presented and
486 AltosUI will interact with an altimeter over the radio link.
489 One oddity in the current interface is how AltosUI selects the
490 frequency for radio communications. Instead of providing
491 an interface to specifically configure the frequency, it uses
492 whatever frequency was most recently selected for the target
493 TeleDongle device in Monitor Flight mode. If you haven't ever
494 used that mode with the TeleDongle in question, select the
495 Monitor Flight button from the top level UI, and pick the
496 appropriate TeleDongle device. Once the flight monitoring
497 window is open, select the desired frequency and then close it
498 down again. All radio communications will now use that frequency.
503 Save Flight Data—Recover flight data from the rocket without
509 Configure altimeter apogee delays or main deploy heights
510 to respond to changing launch conditions. You can also
511 'reboot' the altimeter. Use this to remotely enable the
512 flight computer by turning TeleMetrum on in "idle" mode,
513 then once the air-frame is oriented for launch, you can
514 reboot the altimeter and have it restart in pad mode
515 without having to climb the scary ladder.
520 Fire Igniters—Test your deployment charges without snaking
521 wires out through holes in the air-frame. Simply assembly the
522 rocket as if for flight with the apogee and main charges
523 loaded, then remotely command the altimeter to fire the
529 Operation over the radio link for configuring an altimeter, ground
530 testing igniters, and so forth uses the same RF frequencies as flight
531 telemetry. To configure the desired TeleDongle frequency, select
532 the monitor flight tab, then use the frequency selector and
533 close the window before performing other desired radio operations.
536 TeleMetrum only enables radio commanding in 'idle' mode, so
537 make sure you have TeleMetrum lying horizontally when you turn
538 it on. Otherwise, TeleMetrum will start in 'pad' mode ready for
539 flight, and will not be listening for command packets from TeleDongle.
542 TeleMini listens for a command packet for five seconds after
543 first being turned on, if it doesn't hear anything, it enters
544 'pad' mode, ready for flight and will no longer listen for
545 command packets. The easiest way to connect to TeleMini is to
546 initiate the command and select the TeleDongle device. At this
547 point, the TeleDongle will be attempting to communicate with
548 the TeleMini. Now turn TeleMini on, and it should immediately
549 start communicating with the TeleDongle and the desired
550 operation can be performed.
553 You can monitor the operation of the radio link by watching the
554 lights on the devices. The red LED will flash each time a packet
555 is transmitted, while the green LED will light up on TeleDongle when
556 it is waiting to receive a packet from the altimeter.
560 <title>Ground Testing </title>
562 An important aspect of preparing a rocket using electronic deployment
563 for flight is ground testing the recovery system. Thanks
564 to the bi-directional radio link central to the Altus Metrum system,
565 this can be accomplished in a TeleMetrum or TeleMini equipped rocket
566 with less work than you may be accustomed to with other systems. It
570 Just prep the rocket for flight, then power up the altimeter
571 in "idle" mode (placing air-frame horizontal for TeleMetrum or
572 selected the Configure Altimeter tab for TeleMini). This will cause
573 the firmware to go into "idle" mode, in which the normal flight
574 state machine is disabled and charges will not fire without
575 manual command. You can now command the altimeter to fire the apogee
576 or main charges from a safe distance using your computer and
577 TeleDongle and the Fire Igniter tab to complete ejection testing.
581 <title>Radio Link </title>
583 The chip our boards are based on incorporates an RF transceiver, but
584 it's not a full duplex system... each end can only be transmitting or
585 receiving at any given moment. So we had to decide how to manage the
589 By design, the altimeter firmware listens for the radio link when
590 it's in "idle mode", which
591 allows us to use the radio link to configure the rocket, do things like
592 ejection tests, and extract data after a flight without having to
593 crack open the air-frame. However, when the board is in "flight
594 mode", the altimeter only
595 transmits and doesn't listen at all. That's because we want to put
596 ultimate priority on event detection and getting telemetry out of
598 the radio in case the rocket crashes and we aren't able to extract
602 We don't use a 'normal packet radio' mode like APRS because they're
603 just too inefficient. The GFSK modulation we use is FSK with the
604 base-band pulses passed through a
605 Gaussian filter before they go into the modulator to limit the
606 transmitted bandwidth. When combined with the hardware forward error
607 correction support in the cc1111 chip, this allows us to have a very
608 robust 38.4 kilobit data link with only 10 milliwatts of transmit
609 power, a whip antenna in the rocket, and a hand-held Yagi on the
610 ground. We've had flights to above 21k feet AGL with great reception,
611 and calculations suggest we should be good to well over 40k feet AGL
612 with a 5-element yagi on the ground. We hope to fly boards to higher
613 altitudes over time, and would of course appreciate customer feedback
614 on performance in higher altitude flights!
618 <title>Configurable Parameters</title>
620 Configuring an Altus Metrum altimeter for flight is very
621 simple. Even on our baro-only TeleMini board, the use of a Kalman
622 filter means there is no need to set a "mach delay". The few
623 configurable parameters can all be set using AltosUI over USB or
624 or radio link via TeleDongle.
627 <title>Radio Frequency</title>
629 Altus Metrum boards support radio frequencies in the 70cm
630 band. By default, the configuration interface provides a
631 list of 10 "standard" frequencies in 100kHz channels starting at
632 434.550MHz. However, the firmware supports use of
633 any 50kHz multiple within the 70cm band. At any given
634 launch, we highly recommend coordinating when and by whom each
635 frequency will be used to avoid interference. And of course, both
636 altimeter and TeleDongle must be configured to the same
637 frequency to successfully communicate with each other.
641 <title>Apogee Delay</title>
643 Apogee delay is the number of seconds after the altimeter detects flight
644 apogee that the drogue charge should be fired. In most cases, this
645 should be left at the default of 0. However, if you are flying
646 redundant electronics such as for an L3 certification, you may wish
647 to set one of your altimeters to a positive delay so that both
648 primary and backup pyrotechnic charges do not fire simultaneously.
651 The Altus Metrum apogee detection algorithm fires exactly at
652 apogee. If you are also flying an altimeter like the
653 PerfectFlite MAWD, which only supports selecting 0 or 1
654 seconds of apogee delay, you may wish to set the MAWD to 0
655 seconds delay and set the TeleMetrum to fire your backup 2
656 or 3 seconds later to avoid any chance of both charges
657 firing simultaneously. We've flown several air-frames this
658 way quite happily, including Keith's successful L3 cert.
662 <title>Main Deployment Altitude</title>
664 By default, the altimeter will fire the main deployment charge at an
665 elevation of 250 meters (about 820 feet) above ground. We think this
666 is a good elevation for most air-frames, but feel free to change this
667 to suit. In particular, if you are flying two altimeters, you may
669 deployment elevation for the backup altimeter to be something lower
670 than the primary so that both pyrotechnic charges don't fire
675 <title>Maximum Flight Log</title>
677 TeleMetrum version 1.1 and 1.2 have 2MB of on-board flash storage,
678 enough to hold over 40 minutes of data at full data rate
679 (100 samples/second). TeleMetrum 1.0 has 1MB of on-board
680 storage. As data are stored at a reduced rate during descent
681 (10 samples/second), there's plenty of space to store many
682 flights worth of data.
685 The on-board flash is partitioned into separate flight logs,
686 each of a fixed maximum size. Increase the maximum size of
687 each log and you reduce the number of flights that can be
688 stored. Decrease the size and TeleMetrum can store more
692 All of the configuration data is also stored in the flash
693 memory, which consumes 64kB on TeleMetrum v1.1/v1.2 and 256B on
694 TeleMetrum v1.0. This configuration space is not available
695 for storing flight log data.
698 To compute the amount of space needed for a single flight,
699 you can multiply the expected ascent time (in seconds) by
700 800, multiply the expected descent time (in seconds) by 80
701 and add the two together. That will slightly under-estimate
702 the storage (in bytes) needed for the flight. For instance,
703 a flight spending 20 seconds in ascent and 150 seconds in
704 descent will take about (20 * 800) + (150 * 80) = 28000
705 bytes of storage. You could store dozens of these flights in
709 The default size, 192kB, allows for 10 flights of storage on
710 TeleMetrum v1.1/v1.2 and 5 flights on TeleMetrum v1.0. This
711 ensures that you won't need to erase the memory before
712 flying each time while still allowing more than sufficient
713 storage for each flight.
716 As TeleMini does not contain an accelerometer, it stores
717 data at 10 samples per second during ascent and one sample
718 per second during descent. Each sample is a two byte reading
719 from the barometer. These are stored in 5kB of
720 on-chip flash memory which can hold 256 seconds at the
721 ascent rate or 2560 seconds at the descent rate. Because of
722 the limited storage, TeleMini cannot hold data for more than
723 one flight, and so must be erased after each flight or it
724 will not capture data for subsequent flights.
728 <title>Ignite Mode</title>
730 Instead of firing one charge at apogee and another charge at
731 a fixed height above the ground, you can configure the
732 altimeter to fire both at apogee or both during
733 descent. This was added to support an airframe that has two
734 TeleMetrum computers, one in the fin can and one in the
738 Providing the ability to use both igniters for apogee or
739 main allows some level of redundancy without needing two
740 flight computers. In Redundant Apogee or Redundant Main
741 mode, the two charges will be fired two seconds apart.
745 <title>Pad Orientation</title>
747 TeleMetrum measures acceleration along the axis of the
748 board. Which way the board is oriented affects the sign of
749 the acceleration value. Instead of trying to guess which way
750 the board is mounted in the air frame, TeleMetrum must be
751 explicitly configured for either Antenna Up or Antenna
752 Down. The default, Antenna Up, expects the end of the
753 TeleMetrum board connected to the 70cm antenna to be nearest
754 the nose of the rocket, with the end containing the screw
755 terminals nearest the tail.
763 <title>AltosUI</title>
765 The AltosUI program provides a graphical user interface for
766 interacting with the Altus Metrum product family, including
767 TeleMetrum, TeleMini and TeleDongle. AltosUI can monitor telemetry data,
768 configure TeleMetrum, TeleMini and TeleDongle devices and many other
769 tasks. The primary interface window provides a selection of
770 buttons, one for each major activity in the system. This manual
771 is split into chapters, each of which documents one of the tasks
772 provided from the top-level toolbar.
775 <title>Monitor Flight</title>
776 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
778 Selecting this item brings up a dialog box listing all of the
779 connected TeleDongle devices. When you choose one of these,
780 AltosUI will create a window to display telemetry data as
781 received by the selected TeleDongle device.
784 All telemetry data received are automatically recorded in
785 suitable log files. The name of the files includes the current
786 date and rocket serial and flight numbers.
789 The radio frequency being monitored by the TeleDongle device is
790 displayed at the top of the window. You can configure the
791 frequency by clicking on the frequency box and selecting the desired
792 frequency. AltosUI remembers the last frequency selected for each
793 TeleDongle and selects that automatically the next time you use
797 Below the TeleDongle frequency selector, the window contains a few
798 significant pieces of information about the altimeter providing
799 the telemetry data stream:
803 <para>The configured call-sign</para>
806 <para>The device serial number</para>
809 <para>The flight number. Each altimeter remembers how many
815 The rocket flight state. Each flight passes through several
816 states including Pad, Boost, Fast, Coast, Drogue, Main and
822 The Received Signal Strength Indicator value. This lets
823 you know how strong a signal TeleDongle is receiving. The
824 radio inside TeleDongle operates down to about -99dBm;
825 weaker signals may not be receivable. The packet link uses
826 error detection and correction techniques which prevent
827 incorrect data from being reported.
832 The age of the displayed data, in seconds since the last
833 successfully received telemetry packet. In normal operation
834 this will stay in the low single digits. If the number starts
835 counting up, then you are no longer receiving data over the radio
836 link from the flight computer.
841 Finally, the largest portion of the window contains a set of
842 tabs, each of which contain some information about the rocket.
843 They're arranged in 'flight order' so that as the flight
844 progresses, the selected tab automatically switches to display
845 data relevant to the current state of the flight. You can select
846 other tabs at any time. The final 'table' tab displays all of
847 the raw telemetry values in one place in a spreadsheet-like format.
850 <title>Launch Pad</title>
852 The 'Launch Pad' tab shows information used to decide when the
853 rocket is ready for flight. The first elements include red/green
854 indicators, if any of these is red, you'll want to evaluate
855 whether the rocket is ready to launch:
859 Battery Voltage. This indicates whether the Li-Po battery
860 powering the TeleMetrum has sufficient charge to last for
861 the duration of the flight. A value of more than
862 3.7V is required for a 'GO' status.
867 Apogee Igniter Voltage. This indicates whether the apogee
868 igniter has continuity. If the igniter has a low
869 resistance, then the voltage measured here will be close
870 to the Li-Po battery voltage. A value greater than 3.2V is
871 required for a 'GO' status.
876 Main Igniter Voltage. This indicates whether the main
877 igniter has continuity. If the igniter has a low
878 resistance, then the voltage measured here will be close
879 to the Li-Po battery voltage. A value greater than 3.2V is
880 required for a 'GO' status.
885 On-board Data Logging. This indicates whether there is
886 space remaining on-board to store flight data for the
887 upcoming flight. If you've downloaded data, but failed
888 to erase flights, there may not be any space
889 left. TeleMetrum can store multiple flights, depending
890 on the configured maximum flight log size. TeleMini
891 stores only a single flight, so it will need to be
892 downloaded and erased after each flight to capture
893 data. This only affects on-board flight logging; the
894 altimeter will still transmit telemetry and fire
895 ejection charges at the proper times.
900 GPS Locked. For a TeleMetrum device, this indicates whether the GPS receiver is
901 currently able to compute position information. GPS requires
902 at least 4 satellites to compute an accurate position.
907 GPS Ready. For a TeleMetrum device, this indicates whether GPS has reported at least
908 10 consecutive positions without losing lock. This ensures
909 that the GPS receiver has reliable reception from the
915 The Launchpad tab also shows the computed launch pad position
916 and altitude, averaging many reported positions to improve the
922 <title>Ascent</title>
924 This tab is shown during Boost, Fast and Coast
925 phases. The information displayed here helps monitor the
926 rocket as it heads towards apogee.
929 The height, speed and acceleration are shown along with the
930 maximum values for each of them. This allows you to quickly
931 answer the most commonly asked questions you'll hear during
935 The current latitude and longitude reported by the TeleMetrum GPS are
936 also shown. Note that under high acceleration, these values
937 may not get updated as the GPS receiver loses position
938 fix. Once the rocket starts coasting, the receiver should
939 start reporting position again.
942 Finally, the current igniter voltages are reported as in the
943 Launch Pad tab. This can help diagnose deployment failures
944 caused by wiring which comes loose under high acceleration.
948 <title>Descent</title>
950 Once the rocket has reached apogee and (we hope) activated the
951 apogee charge, attention switches to tracking the rocket on
952 the way back to the ground, and for dual-deploy flights,
953 waiting for the main charge to fire.
956 To monitor whether the apogee charge operated correctly, the
957 current descent rate is reported along with the current
958 height. Good descent rates vary based on the choice of recovery
959 components, but generally range from 15-30m/s on drogue and should
960 be below 10m/s when under the main parachute in a dual-deploy flight.
963 For TeleMetrum altimeters, you can locate the rocket in the
964 sky using the elevation and bearing information to figure
965 out where to look. Elevation is in degrees above the
966 horizon. Bearing is reported in degrees relative to true
967 north. Range can help figure out how big the rocket will
968 appear. Ground Distance shows how far it is to a point
969 directly under the rocket and can help figure out where the
970 rocket is likely to land. Note that all of these values are
971 relative to the pad location. If the elevation is near 90°,
972 the rocket is over the pad, not over you.
975 Finally, the igniter voltages are reported in this tab as
976 well, both to monitor the main charge as well as to see what
977 the status of the apogee charge is. Note that some commercial
978 e-matches are designed to retain continuity even after being
979 fired, and will continue to show as green or return from red to
984 <title>Landed</title>
986 Once the rocket is on the ground, attention switches to
987 recovery. While the radio signal is often lost once the
988 rocket is on the ground, the last reported GPS position is
989 generally within a short distance of the actual landing location.
992 The last reported GPS position is reported both by
993 latitude and longitude as well as a bearing and distance from
994 the launch pad. The distance should give you a good idea of
995 whether to walk or hitch a ride. Take the reported
996 latitude and longitude and enter them into your hand-held GPS
997 unit and have that compute a track to the landing location.
1000 Both TeleMini and TeleMetrum will continue to transmit RDF
1001 tones after landing, allowing you to locate the rocket by
1002 following the radio signal if necessary. You may need to get
1003 away from the clutter of the flight line, or even get up on
1004 a hill (or your neighbor's RV roof) to receive the RDF signal.
1007 The maximum height, speed and acceleration reported
1008 during the flight are displayed for your admiring observers.
1009 The accuracy of these immediate values depends on the quality
1010 of your radio link and how many packets were received.
1011 Recovering the on-board data after flight will likely yield
1012 more precise results.
1015 To get more detailed information about the flight, you can
1016 click on the 'Graph Flight' button which will bring up a
1017 graph window for the current flight.
1021 <title>Site Map</title>
1023 When the TeleMetrum has a GPS fix, the Site Map tab will map
1024 the rocket's position to make it easier for you to locate the
1025 rocket, both while it is in the air, and when it has landed. The
1026 rocket's state is indicated by color: white for pad, red for
1027 boost, pink for fast, yellow for coast, light blue for drogue,
1028 dark blue for main, and black for landed.
1031 The map's scale is approximately 3m (10ft) per pixel. The map
1032 can be dragged using the left mouse button. The map will attempt
1033 to keep the rocket roughly centered while data is being received.
1036 Images are fetched automatically via the Google Maps Static API,
1037 and cached on disk for reuse. If map images cannot be downloaded,
1038 the rocket's path will be traced on a dark gray background
1042 You can pre-load images for your favorite launch sites
1043 before you leave home; check out the 'Preload Maps' section below.
1048 <title>Save Flight Data</title>
1050 The altimeter records flight data to its internal flash memory.
1051 TeleMetrum data is recorded at a much higher rate than the telemetry
1052 system can handle, and is not subject to radio drop-outs. As
1053 such, it provides a more complete and precise record of the
1054 flight. The 'Save Flight Data' button allows you to read the
1055 flash memory and write it to disk. As TeleMini has only a barometer, it
1056 records data at the same rate as the telemetry signal, but there will be
1057 no data lost due to telemetry drop-outs.
1060 Clicking on the 'Save Flight Data' button brings up a list of
1061 connected TeleMetrum and TeleDongle devices. If you select a
1062 TeleMetrum device, the flight data will be downloaded from that
1063 device directly. If you select a TeleDongle device, flight data
1064 will be downloaded from an altimeter over radio link via the
1065 specified TeleDongle. See the chapter on Controlling An Altimeter
1066 Over The Radio Link for more information.
1069 After the device has been selected, a dialog showing the
1070 flight data saved in the device will be shown allowing you to
1071 select which flights to download and which to delete. With
1072 version 0.9 or newer firmware, you must erase flights in order
1073 for the space they consume to be reused by another
1074 flight. This prevents accidentally losing flight data
1075 if you neglect to download data before flying again. Note that
1076 if there is no more space available in the device, then no
1077 data will be recorded during the next flight.
1080 The file name for each flight log is computed automatically
1081 from the recorded flight date, altimeter serial number and
1082 flight number information.
1086 <title>Replay Flight</title>
1088 Select this button and you are prompted to select a flight
1089 record file, either a .telem file recording telemetry data or a
1090 .eeprom file containing flight data saved from the altimeter
1094 Once a flight record is selected, the flight monitor interface
1095 is displayed and the flight is re-enacted in real time. Check
1096 the Monitor Flight chapter above to learn how this window operates.
1100 <title>Graph Data</title>
1102 Select this button and you are prompted to select a flight
1103 record file, either a .telem file recording telemetry data or a
1104 .eeprom file containing flight data saved from
1108 Once a flight record is selected, a window with two tabs is
1109 opened. The first tab contains a graph with acceleration
1110 (blue), velocity (green) and altitude (red) of the flight,
1111 measured in metric units. The
1112 apogee(yellow) and main(magenta) igniter voltages are also
1113 displayed; high voltages indicate continuity, low voltages
1114 indicate open circuits. The second tab contains some basic
1118 The graph can be zoomed into a particular area by clicking and
1119 dragging down and to the right. Once zoomed, the graph can be
1120 reset by clicking and dragging up and to the left. Holding down
1121 control and clicking and dragging allows the graph to be panned.
1122 The right mouse button causes a pop-up menu to be displayed, giving
1123 you the option save or print the plot.
1126 Note that telemetry files will generally produce poor graphs
1127 due to the lower sampling rate and missed telemetry packets.
1128 Use saved flight data in .eeprom files for graphing where possible.
1132 <title>Export Data</title>
1134 This tool takes the raw data files and makes them available for
1135 external analysis. When you select this button, you are prompted to
1137 data file (either .eeprom or .telem will do, remember that
1138 .eeprom files contain higher resolution and more continuous
1139 data). Next, a second dialog appears which is used to select
1140 where to write the resulting file. It has a selector to choose
1141 between CSV and KML file formats.
1144 <title>Comma Separated Value Format</title>
1146 This is a text file containing the data in a form suitable for
1147 import into a spreadsheet or other external data analysis
1148 tool. The first few lines of the file contain the version and
1149 configuration information from the altimeter, then
1150 there is a single header line which labels all of the
1151 fields. All of these lines start with a '#' character which
1152 many tools can be configured to skip over.
1155 The remaining lines of the file contain the data, with each
1156 field separated by a comma and at least one space. All of
1157 the sensor values are converted to standard units, with the
1158 barometric data reported in both pressure, altitude and
1159 height above pad units.
1163 <title>Keyhole Markup Language (for Google Earth)</title>
1165 This is the format used by Google Earth to provide an overlay
1166 within that application. With this, you can use Google Earth to
1167 see the whole flight path in 3D.
1172 <title>Configure Altimeter</title>
1174 Select this button and then select either a TeleMetrum or
1175 TeleDongle Device from the list provided. Selecting a TeleDongle
1176 device will use the radio link to configure a remote altimeter.
1179 The first few lines of the dialog provide information about the
1180 connected device, including the product name,
1181 software version and hardware serial number. Below that are the
1182 individual configuration entries.
1185 At the bottom of the dialog, there are four buttons:
1190 Save. This writes any changes to the
1191 configuration parameter block in flash memory. If you don't
1192 press this button, any changes you make will be lost.
1197 Reset. This resets the dialog to the most recently saved values,
1198 erasing any changes you have made.
1203 Reboot. This reboots the device. Use this to
1204 switch from idle to pad mode by rebooting once the rocket is
1205 oriented for flight, or to confirm changes you think you saved
1211 Close. This closes the dialog. Any unsaved changes will be
1217 The rest of the dialog contains the parameters to be configured.
1220 <title>Main Deploy Altitude</title>
1222 This sets the altitude (above the recorded pad altitude) at
1223 which the 'main' igniter will fire. The drop-down menu shows
1224 some common values, but you can edit the text directly and
1225 choose whatever you like. If the apogee charge fires below
1226 this altitude, then the main charge will fire two seconds
1227 after the apogee charge fires.
1231 <title>Apogee Delay</title>
1233 When flying redundant electronics, it's often important to
1234 ensure that multiple apogee charges don't fire at precisely
1235 the same time, as that can over pressurize the apogee deployment
1236 bay and cause a structural failure of the air-frame. The Apogee
1237 Delay parameter tells the flight computer to fire the apogee
1238 charge a certain number of seconds after apogee has been
1243 <title>Radio Frequency</title>
1245 This configures which of the configured frequencies to use for both
1246 telemetry and packet command mode. Note that if you set this
1247 value via packet command mode, you will have to reconfigure
1248 the TeleDongle frequency before you will be able to use packet
1253 <title>Radio Calibration</title>
1255 The radios in every Altus Metrum device are calibrated at the
1256 factory to ensure that they transmit and receive on the
1257 specified frequency. If you need to you can adjust the calibration
1258 by changing this value. Do not do this without understanding what
1259 the value means, read the appendix on calibration and/or the source
1260 code for more information. To change a TeleDongle's calibration,
1261 you must reprogram the unit completely.
1265 <title>Callsign</title>
1267 This sets the call sign included in each telemetry packet. Set this
1268 as needed to conform to your local radio regulations.
1272 <title>Maximum Flight Log Size</title>
1274 This sets the space (in kilobytes) allocated for each flight
1275 log. The available space will be divided into chunks of this
1276 size. A smaller value will allow more flights to be stored,
1277 a larger value will record data from longer flights.
1281 <title>Ignite Mode</title>
1283 TeleMetrum and TeleMini provide two igniter channels as they
1284 were originally designed as dual-deploy flight
1285 computers. This configuration parameter allows the two
1286 channels to be used in different configurations.
1291 Dual Deploy. This is the usual mode of operation; the
1292 'apogee' channel is fired at apogee and the 'main'
1293 channel at the height above ground specified by the
1294 'Main Deploy Altitude' during descent.
1299 Redundant Apogee. This fires both channels at
1300 apogee, the 'apogee' channel first followed after a two second
1301 delay by the 'main' channel.
1306 Redundant Main. This fires both channels at the
1307 height above ground specified by the Main Deploy
1308 Altitude setting during descent. The 'apogee'
1309 channel is fired first, followed after a two second
1310 delay by the 'main' channel.
1316 <title>Pad Orientation</title>
1318 Because it includes an accelerometer, TeleMetrum is
1319 sensitive to the orientation of the board. By default, it
1320 expects the antenna end to point forward. This parameter
1321 allows that default to be changed, permitting the board to
1322 be mounted with the antenna pointing aft instead.
1327 Antenna Up. In this mode, the antenna end of the
1328 TeleMetrum board must point forward, in line with the
1329 expected flight path.
1334 Antenna Down. In this mode, the antenna end of the
1335 TeleMetrum board must point aft, in line with the
1336 expected flight path.
1343 <title>Configure AltosUI</title>
1345 This button presents a dialog so that you can configure the AltosUI global settings.
1348 <title>Voice Settings</title>
1350 AltosUI provides voice announcements during flight so that you
1351 can keep your eyes on the sky and still get information about
1352 the current flight status. However, sometimes you don't want
1357 <para>Enable—turns all voice announcements on and off</para>
1361 Test Voice—Plays a short message allowing you to verify
1362 that the audio system is working and the volume settings
1369 <title>Log Directory</title>
1371 AltosUI logs all telemetry data and saves all TeleMetrum flash
1372 data to this directory. This directory is also used as the
1373 staring point when selecting data files for display or export.
1376 Click on the directory name to bring up a directory choosing
1377 dialog, select a new directory and click 'Select Directory' to
1378 change where AltosUI reads and writes data files.
1382 <title>Callsign</title>
1384 This value is transmitted in each command packet sent from
1385 TeleDongle and received from an altimeter. It is not used in
1386 telemetry mode, as the callsign configured in the altimeter board
1387 is included in all telemetry packets. Configure this
1388 with the AltosUI operators call sign as needed to comply with
1389 your local radio regulations.
1393 <title>Imperial Units</title>
1395 This switches between metric units (meters) and imperial
1396 units (feet and miles). This affects the display of values
1397 use during flight monitoring, data graphing and all of the
1398 voice announcements. It does not change the units used when
1399 exporting to CSV files, those are always produced in metric units.
1403 <title>Font Size</title>
1405 Selects the set of fonts used in the flight monitor
1406 window. Choose between the small, medium and large sets.
1410 <title>Serial Debug</title>
1412 This causes all communication with a connected device to be
1413 dumped to the console from which AltosUI was started. If
1414 you've started it from an icon or menu entry, the output
1415 will simply be discarded. This mode can be useful to debug
1416 various serial communication issues.
1420 <title>Manage Frequencies</title>
1422 This brings up a dialog where you can configure the set of
1423 frequencies shown in the various frequency menus. You can
1424 add as many as you like, or even reconfigure the default
1425 set. Changing this list does not affect the frequency
1426 settings of any devices, it only changes the set of
1427 frequencies shown in the menus.
1432 <title>Configure Groundstation</title>
1434 Select this button and then select a TeleDongle Device from the list provided.
1437 The first few lines of the dialog provide information about the
1438 connected device, including the product name,
1439 software version and hardware serial number. Below that are the
1440 individual configuration entries.
1443 Note that the TeleDongle itself doesn't save any configuration
1444 data, the settings here are recorded on the local machine in
1445 the Java preferences database. Moving the TeleDongle to
1446 another machine, or using a different user account on the same
1447 machine will cause settings made here to have no effect.
1450 At the bottom of the dialog, there are three buttons:
1455 Save. This writes any changes to the
1456 local Java preferences file. If you don't
1457 press this button, any changes you make will be lost.
1462 Reset. This resets the dialog to the most recently saved values,
1463 erasing any changes you have made.
1468 Close. This closes the dialog. Any unsaved changes will be
1474 The rest of the dialog contains the parameters to be configured.
1477 <title>Frequency</title>
1479 This configures the frequency to use for both telemetry and
1480 packet command mode. Set this before starting any operation
1481 involving packet command mode so that it will use the right
1482 frequency. Telemetry monitoring mode also provides a menu to
1483 change the frequency, and that menu also sets the same Java
1484 preference value used here.
1488 <title>Radio Calibration</title>
1490 The radios in every Altus Metrum device are calibrated at the
1491 factory to ensure that they transmit and receive on the
1492 specified frequency. To change a TeleDongle's calibration,
1493 you must reprogram the unit completely, so this entry simply
1494 shows the current value and doesn't allow any changes.
1499 <title>Flash Image</title>
1501 This reprograms any Altus Metrum device by using a TeleMetrum
1502 or TeleDongle as a programming dongle. Please read the
1503 directions for flashing devices in the Updating Device
1504 Firmware chapter below.
1507 Once you have the programmer and target devices connected,
1508 push the 'Flash Image' button. That will present a dialog box
1509 listing all of the connected devices. Carefully select the
1510 programmer device, not the device to be programmed.
1513 Next, select the image to flash to the device. These are named
1514 with the product name and firmware version. The file selector
1515 will start in the directory containing the firmware included
1516 with the AltosUI package. Navigate to the directory containing
1517 the desired firmware if it isn't there.
1520 Next, a small dialog containing the device serial number and
1521 RF calibration values should appear. If these values are
1522 incorrect (possibly due to a corrupted image in the device),
1523 enter the correct values here.
1526 Finally, a dialog containing a progress bar will follow the
1527 programming process.
1530 When programming is complete, the target device will
1531 reboot. Note that if the target device is connected via USB, you
1532 will have to unplug it and then plug it back in for the USB
1533 connection to reset so that you can communicate with the device
1538 <title>Fire Igniter</title>
1540 This activates the igniter circuits in TeleMetrum to help test
1541 recovery systems deployment. Because this command can operate
1542 over the Packet Command Link, you can prepare the rocket as
1543 for flight and then test the recovery system without needing
1544 to snake wires inside the air-frame.
1547 Selecting the 'Fire Igniter' button brings up the usual device
1548 selection dialog. Pick the desired TeleDongle or TeleMetrum
1549 device. This brings up another window which shows the current
1550 continuity test status for both apogee and main charges.
1553 Next, select the desired igniter to fire. This will enable the
1557 Select the 'Arm' button. This enables the 'Fire' button. The
1558 word 'Arm' is replaced by a countdown timer indicating that
1559 you have 10 seconds to press the 'Fire' button or the system
1560 will deactivate, at which point you start over again at
1561 selecting the desired igniter.
1565 <title>Scan Channels</title>
1567 This listens for telemetry packets on all of the configured
1568 frequencies, displaying information about each device it
1569 receives a packet from. You can select which of the three
1570 telemetry formats should be tried; by default, it only listens
1571 for the standard telemetry packets used in v1.0 and later
1576 <title>Load Maps</title>
1578 Before heading out to a new launch site, you can use this to
1579 load satellite images in case you don't have internet
1580 connectivity at the site. This loads a fairly large area
1581 around the launch site, which should cover any flight you're likely to make.
1584 There's a drop-down menu of launch sites we know about; if
1585 your favorites aren't there, please let us know the lat/lon
1586 and name of the site. The contents of this list are actually
1587 downloaded at run-time, so as new sites are sent in, they'll
1588 get automatically added to this list.
1591 If the launch site isn't in the list, you can manually enter the lat/lon values
1594 Clicking the 'Load Map' button will fetch images from Google
1595 Maps; note that Google limits how many images you can fetch at
1596 once, so if you load more than one launch site, you may get
1597 some gray areas in the map which indicate that Google is tired
1598 of sending data to you. Try again later.
1602 <title>Monitor Idle</title>
1604 This brings up a dialog similar to the Monitor Flight UI,
1605 except it works with the altimeter in "idle" mode by sending
1606 query commands to discover the current state rather than
1607 listening for telemetry packets.
1612 <title>AltosDroid</title>
1614 AltosDroid provides the same flight monitoring capabilities as
1615 AltosUI, but runs on Android devices and is designed to connect
1616 to a TeleBT receiver over Bluetooth™. Altos Droid monitors
1617 telemetry data, logging it to internal storage in the Android
1618 device, and presents that data in a UI the same way the 'Monitor
1619 Flight' window does in AltosUI.
1622 This manual will explain how to configure AltosDroid, connect
1623 to TeleBT, operate the flight monitoring interface and describe
1624 what the displayed data means.
1627 <title>Installing AltosDroid</title>
1629 AltosDroid is included in the Google Play store. To install
1630 it on your Android device, open open the Google Play Store
1631 application and search for "altosdroid". Make sure you don't
1632 have a space between "altos" and "droid" or you probably won't
1633 find what you want. That should bring you to the right page
1634 from which you can download and install the application.
1638 <title>Connecting to TeleBT</title>
1640 Press the Android 'Menu' button or soft-key to see the
1641 configuration options available. Select the 'Connect a device'
1642 option and then the 'Scan for devices' entry at the bottom to
1643 look for your TeleBT device. Select your device, and when it
1644 asks for the code, enter '1234'.
1647 Subsequent connections will not require you to enter that
1648 code, and your 'paired' device will appear in the list without
1653 <title>Configuring AltosDroid</title>
1655 The only configuration option available for AltosDroid is
1656 which frequency to listen on. Press the Android 'Menu' button
1657 or soft-key and pick the 'Select radio frequency' entry. That
1658 brings up a menu of pre-set radio frequencies; pick the one
1659 which matches your altimeter.
1663 <title>Flight Monitoring</title>
1666 <title>Downloading Flight Logs</title>
1668 Altos Droid always saves every bit of telemetry data it
1669 receives. To download that to a computer for use with AltosUI,
1670 simply remove the SD card from your Android device, or connect
1671 your device to your computer's USB port and browse the files
1672 on that device. You will find '.telem' files in the TeleMetrum
1673 directory that will work with AltosUI directly.
1678 <title>Using Altus Metrum Products</title>
1680 <title>Being Legal</title>
1682 First off, in the US, you need an <ulink url="http://www.altusmetrum.org/Radio/">amateur radio license</ulink> or
1683 other authorization to legally operate the radio transmitters that are part
1688 <title>In the Rocket</title>
1690 In the rocket itself, you just need a <ulink url="http://www.altusmetrum.org/TeleMetrum/">TeleMetrum</ulink> or
1691 <ulink url="http://www.altusmetrum.org/TeleMini/">TeleMini</ulink> board and
1692 a single-cell, 3.7 volt nominal Li-Po rechargeable battery. An
1693 850mAh battery weighs less than a 9V alkaline battery, and will
1694 run a TeleMetrum for hours.
1695 A 110mAh battery weighs less than a triple A battery and will run a TeleMetrum for
1696 a few hours, or a TeleMini for much (much) longer.
1699 By default, we ship the altimeters with a simple wire antenna. If your
1700 electronics bay or the air-frame it resides within is made of carbon fiber,
1701 which is opaque to RF signals, you may choose to have an SMA connector
1702 installed so that you can run a coaxial cable to an antenna mounted
1703 elsewhere in the rocket.
1707 <title>On the Ground</title>
1709 To receive the data stream from the rocket, you need an antenna and short
1710 feed-line connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. If possible, use an SMA to BNC
1711 adapter instead of feedline between the antenna feedpoint and
1712 TeleDongle, as this will give you the best performance. The
1713 TeleDongle in turn plugs directly into the USB port on a notebook
1714 computer. Because TeleDongle looks like a simple serial port, your computer
1715 does not require special device drivers... just plug it in.
1718 The GUI tool, AltosUI, is written in Java and runs across
1719 Linux, Mac OS and Windows. There's also a suite of C tools
1720 for Linux which can perform most of the same tasks.
1723 After the flight, you can use the radio link to extract the more detailed data
1724 logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
1725 TeleMetrum board directly. Pulling out the data without having to open up
1726 the rocket is pretty cool! A USB cable is also how you charge the Li-Po
1727 battery, so you'll want one of those anyway... the same cable used by lots
1728 of digital cameras and other modern electronic stuff will work fine.
1731 If your TeleMetrum-equipped rocket lands out of sight, you may enjoy having a hand-held GPS
1732 receiver, so that you can put in a way-point for the last reported rocket
1733 position before touch-down. This makes looking for your rocket a lot like
1734 Geo-Caching... just go to the way-point and look around starting from there.
1737 You may also enjoy having a ham radio "HT" that covers the 70cm band... you
1738 can use that with your antenna to direction-find the rocket on the ground
1739 the same way you can use a Walston or Beeline tracker. This can be handy
1740 if the rocket is hiding in sage brush or a tree, or if the last GPS position
1741 doesn't get you close enough because the rocket dropped into a canyon, or
1742 the wind is blowing it across a dry lake bed, or something like that... Keith
1743 and Bdale both currently own and use the Yaesu VX-7R at launches.
1746 So, to recap, on the ground the hardware you'll need includes:
1747 <orderedlist inheritnum='inherit' numeration='arabic'>
1749 an antenna and feed-line or adapter
1758 optionally, a hand-held GPS receiver
1761 optionally, an HT or receiver covering 435 MHz
1766 The best hand-held commercial directional antennas we've found for radio
1767 direction finding rockets are from
1768 <ulink url="http://www.arrowantennas.com/" >
1771 The 440-3 and 440-5 are both good choices for finding a
1772 TeleMetrum- or TeleMini- equipped rocket when used with a suitable
1773 70cm HT. TeleDongle and an SMA to BNC adapter fit perfectly
1774 between the driven element and reflector of Arrow antennas.
1778 <title>Data Analysis</title>
1780 Our software makes it easy to log the data from each flight, both the
1781 telemetry received during the flight itself, and the more
1782 complete data log recorded in the flash memory on the altimeter
1783 board. Once this data is on your computer, our post-flight tools make it
1784 easy to quickly get to the numbers everyone wants, like apogee altitude,
1785 max acceleration, and max velocity. You can also generate and view a
1786 standard set of plots showing the altitude, acceleration, and
1787 velocity of the rocket during flight. And you can even export a TeleMetrum data file
1788 usable with Google Maps and Google Earth for visualizing the flight path
1789 in two or three dimensions!
1792 Our ultimate goal is to emit a set of files for each flight that can be
1793 published as a web page per flight, or just viewed on your local disk with
1798 <title>Future Plans</title>
1800 In the future, we intend to offer "companion boards" for the rocket
1801 that will plug in to TeleMetrum to collect additional data, provide
1802 more pyro channels, and so forth.
1805 Also under design is a new flight computer with more sensors, more
1806 pyro channels, and a more powerful radio system designed for use
1807 in multi-stage, complex, and extreme altitude projects.
1810 We are also working on alternatives to TeleDongle. One is a
1811 a stand-alone, hand-held ground terminal that will allow monitoring
1812 the rocket's status, collecting data during flight, and logging data
1813 after flight without the need for a notebook computer on the
1814 flight line. Particularly since it is so difficult to read most
1815 notebook screens in direct sunlight, we think this will be a great
1816 thing to have. We are also working on a TeleDongle variant with
1817 Bluetooth that will work with Android phones and tablets.
1820 Because all of our work is open, both the hardware designs and the
1821 software, if you have some great idea for an addition to the current
1822 Altus Metrum family, feel free to dive in and help! Or let us know
1823 what you'd like to see that we aren't already working on, and maybe
1824 we'll get excited about it too...
1828 <ulink url="http://altusmetrum.org/">web site</ulink> for more news
1829 and information as our family of products evolves!
1834 <title>Altimeter Installation Recommendations</title>
1836 Building high-power rockets that fly safely is hard enough. Mix
1837 in some sophisticated electronics and a bunch of radio energy
1838 and oftentimes you find few perfect solutions. This chapter
1839 contains some suggestions about how to install Altus Metrum
1840 products into the rocket air-frame, including how to safely and
1841 reliably mix a variety of electronics into the same air-frame.
1844 <title>Mounting the Altimeter</title>
1846 The first consideration is to ensure that the altimeter is
1847 securely fastened to the air-frame. For TeleMetrum, we use
1848 nylon standoffs and nylon screws; they're good to at least 50G
1849 and cannot cause any electrical issues on the board. For
1850 TeleMini, we usually cut small pieces of 1/16" balsa to fit
1851 under the screw holes, and then take 2x56 nylon screws and
1852 screw them through the TeleMini mounting holes, through the
1853 balsa and into the underlying material.
1855 <orderedlist inheritnum='inherit' numeration='arabic'>
1857 Make sure TeleMetrum is aligned precisely along the axis of
1858 acceleration so that the accelerometer can accurately
1859 capture data during the flight.
1862 Watch for any metal touching components on the
1863 board. Shorting out connections on the bottom of the board
1864 can cause the altimeter to fail during flight.
1869 <title>Dealing with the Antenna</title>
1871 The antenna supplied is just a piece of solid, insulated,
1872 wire. If it gets damaged or broken, it can be easily
1873 replaced. It should be kept straight and not cut; bending or
1874 cutting it will change the resonant frequency and/or
1875 impedance, making it a less efficient radiator and thus
1876 reducing the range of the telemetry signal.
1879 Keeping metal away from the antenna will provide better range
1880 and a more even radiation pattern. In most rockets, it's not
1881 entirely possible to isolate the antenna from metal
1882 components; there are often bolts, all-thread and wires from other
1883 electronics to contend with. Just be aware that the more stuff
1884 like this around the antenna, the lower the range.
1887 Make sure the antenna is not inside a tube made or covered
1888 with conducting material. Carbon fiber is the most common
1889 culprit here -- CF is a good conductor and will effectively
1890 shield the antenna, dramatically reducing signal strength and
1891 range. Metallic flake paint is another effective shielding
1892 material which is to be avoided around any antennas.
1895 If the ebay is large enough, it can be convenient to simply
1896 mount the altimeter at one end and stretch the antenna out
1897 inside. Taping the antenna to the sled can keep it straight
1898 under acceleration. If there are metal rods, keep the
1899 antenna as far away as possible.
1902 For a shorter ebay, it's quite practical to have the antenna
1903 run through a bulkhead and into an adjacent bay. Drill a small
1904 hole in the bulkhead, pass the antenna wire through it and
1905 then seal it up with glue or clay. We've also used acrylic
1906 tubing to create a cavity for the antenna wire. This works a
1907 bit better in that the antenna is known to stay straight and
1908 not get folded by recovery components in the bay. Angle the
1909 tubing towards the side wall of the rocket and it ends up
1910 consuming very little space.
1913 If you need to place the antenna at a distance from the
1914 altimeter, you can replace the antenna with an edge-mounted
1915 SMA connector, and then run 50Ω coax from the board to the
1916 antenna. Building a remote antenna is beyond the scope of this
1921 <title>Preserving GPS Reception</title>
1923 The GPS antenna and receiver in TeleMetrum are highly
1924 sensitive and normally have no trouble tracking enough
1925 satellites to provide accurate position information for
1926 recovering the rocket. However, there are many ways to
1927 attenuate the GPS signal.
1928 <orderedlist inheritnum='inherit' numeration='arabic'>
1930 Conductive tubing or coatings. Carbon fiber and metal
1931 tubing, or metallic paint will all dramatically attenuate the
1932 GPS signal. We've never heard of anyone successfully
1933 receiving GPS from inside these materials.
1936 Metal components near the GPS patch antenna. These will
1937 de-tune the patch antenna, changing the resonant frequency
1938 away from the L1 carrier and reduce the effectiveness of the
1939 antenna. You can place as much stuff as you like beneath the
1940 antenna as that's covered with a ground plane. But, keep
1941 wires and metal out from above the patch antenna.
1947 <title>Radio Frequency Interference</title>
1949 Any altimeter will generate RFI; the digital circuits use
1950 high-frequency clocks that spray radio interference across a
1951 wide band. Altus Metrum altimeters generate intentional radio
1952 signals as well, increasing the amount of RF energy around the board.
1955 Rocketry altimeters also use precise sensors measuring air
1956 pressure and acceleration. Tiny changes in voltage can cause
1957 these sensor readings to vary by a huge amount. When the
1958 sensors start mis-reporting data, the altimeter can either
1959 fire the igniters at the wrong time, or not fire them at all.
1962 Voltages are induced when radio frequency energy is
1963 transmitted from one circuit to another. Here are things that
1964 influence the induced voltage and current:
1968 Keep wires from different circuits apart. Moving circuits
1969 further apart will reduce RFI.
1972 Avoid parallel wires from different circuits. The longer two
1973 wires run parallel to one another, the larger the amount of
1974 transferred energy. Cross wires at right angles to reduce
1978 Twist wires from the same circuits. Two wires the same
1979 distance from the transmitter will get the same amount of
1980 induced energy which will then cancel out. Any time you have
1981 a wire pair running together, twist the pair together to
1982 even out distances and reduce RFI. For altimeters, this
1983 includes battery leads, switch hookups and igniter
1987 Avoid resonant lengths. Know what frequencies are present
1988 in the environment and avoid having wire lengths near a
1989 natural resonant length. Altusmetrum products transmit on the
1990 70cm amateur band, so you should avoid lengths that are a
1991 simple ratio of that length; essentially any multiple of 1/4
1992 of the wavelength (17.5cm).
1997 <title>The Barometric Sensor</title>
1999 Altusmetrum altimeters measure altitude with a barometric
2000 sensor, essentially measuring the amount of air above the
2001 rocket to figure out how high it is. A large number of
2002 measurements are taken as the altimeter initializes itself to
2003 figure out the pad altitude. Subsequent measurements are then
2004 used to compute the height above the pad.
2007 To accurately measure atmospheric pressure, the ebay
2008 containing the altimeter must be vented outside the
2009 air-frame. The vent must be placed in a region of linear
2010 airflow, have smooth edges, and away from areas of increasing or
2011 decreasing pressure.
2014 The barometric sensor in the altimeter is quite sensitive to
2015 chemical damage from the products of APCP or BP combustion, so
2016 make sure the ebay is carefully sealed from any compartment
2017 which contains ejection charges or motors.
2021 <title>Ground Testing</title>
2023 The most important aspect of any installation is careful
2024 ground testing. Bringing an air-frame up to the LCO table which
2025 hasn't been ground tested can lead to delays or ejection
2026 charges firing on the pad, or, even worse, a recovery system
2030 Do a 'full systems' test that includes wiring up all igniters
2031 without any BP and turning on all of the electronics in flight
2032 mode. This will catch any mistakes in wiring and any residual
2033 RFI issues that might accidentally fire igniters at the wrong
2034 time. Let the air-frame sit for several minutes, checking for
2035 adequate telemetry signal strength and GPS lock. If any igniters
2036 fire unexpectedly, find and resolve the issue before loading any
2040 Ground test the ejection charges. Prepare the rocket for
2041 flight, loading ejection charges and igniters. Completely
2042 assemble the air-frame and then use the 'Fire Igniters'
2043 interface through a TeleDongle to command each charge to
2044 fire. Make sure the charge is sufficient to robustly separate
2045 the air-frame and deploy the recovery system.
2050 <title>Updating Device Firmware</title>
2052 The big concept to understand is that you have to use a
2053 TeleDongle as a programmer to update a TeleMetrum or TeleMini,
2054 and a TeleMetrum or other TeleDongle to program the TeleDongle
2055 Due to limited memory resources in the cc1111, we don't support
2056 programming directly over USB.
2059 You may wish to begin by ensuring you have current firmware images.
2060 These are distributed as part of the AltOS software bundle that
2061 also includes the AltosUI ground station program. Newer ground
2062 station versions typically work fine with older firmware versions,
2063 so you don't need to update your devices just to try out new
2064 software features. You can always download the most recent
2065 version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
2068 We recommend updating the altimeter first, before updating TeleDongle.
2071 <title>Updating TeleMetrum Firmware</title>
2072 <orderedlist inheritnum='inherit' numeration='arabic'>
2074 Find the 'programming cable' that you got as part of the starter
2075 kit, that has a red 8-pin MicroMaTch connector on one end and a
2076 red 4-pin MicroMaTch connector on the other end.
2079 Take the 2 screws out of the TeleDongle case to get access
2080 to the circuit board.
2083 Plug the 8-pin end of the programming cable to the
2084 matching connector on the TeleDongle, and the 4-pin end to the
2085 matching connector on the TeleMetrum.
2086 Note that each MicroMaTch connector has an alignment pin that
2087 goes through a hole in the PC board when you have the cable
2091 Attach a battery to the TeleMetrum board.
2094 Plug the TeleDongle into your computer's USB port, and power
2098 Run AltosUI, and select 'Flash Image' from the File menu.
2101 Pick the TeleDongle device from the list, identifying it as the
2105 Select the image you want put on the TeleMetrum, which should have a
2106 name in the form telemetrum-v1.2-1.0.0.ihx. It should be visible
2107 in the default directory, if not you may have to poke around
2108 your system to find it.
2111 Make sure the configuration parameters are reasonable
2112 looking. If the serial number and/or RF configuration
2113 values aren't right, you'll need to change them.
2116 Hit the 'OK' button and the software should proceed to flash
2117 the TeleMetrum with new firmware, showing a progress bar.
2120 Confirm that the TeleMetrum board seems to have updated OK, which you
2121 can do by plugging in to it over USB and using a terminal program
2122 to connect to the board and issue the 'v' command to check
2126 If something goes wrong, give it another try.
2131 <title>Updating TeleMini Firmware</title>
2132 <orderedlist inheritnum='inherit' numeration='arabic'>
2134 You'll need a special 'programming cable' to reprogram the
2135 TeleMini. It's available on the Altus Metrum web store, or
2136 you can make your own using an 8-pin MicroMaTch connector on
2137 one end and a set of four pins on the other.
2140 Take the 2 screws out of the TeleDongle case to get access
2141 to the circuit board.
2144 Plug the 8-pin end of the programming cable to the matching
2145 connector on the TeleDongle, and the 4-pins into the holes
2146 in the TeleMini circuit board. Note that the MicroMaTch
2147 connector has an alignment pin that goes through a hole in
2148 the PC board when you have the cable oriented correctly, and
2149 that pin 1 on the TeleMini board is marked with a square pad
2150 while the other pins have round pads.
2153 Attach a battery to the TeleMini board.
2156 Plug the TeleDongle into your computer's USB port, and power
2160 Run AltosUI, and select 'Flash Image' from the File menu.
2163 Pick the TeleDongle device from the list, identifying it as the
2167 Select the image you want put on the TeleMini, which should have a
2168 name in the form telemini-v1.0-1.0.0.ihx. It should be visible
2169 in the default directory, if not you may have to poke around
2170 your system to find it.
2173 Make sure the configuration parameters are reasonable
2174 looking. If the serial number and/or RF configuration
2175 values aren't right, you'll need to change them.
2178 Hit the 'OK' button and the software should proceed to flash
2179 the TeleMini with new firmware, showing a progress bar.
2182 Confirm that the TeleMini board seems to have updated OK, which you
2183 can do by configuring it over the radio link through the TeleDongle, or
2184 letting it come up in "flight" mode and listening for telemetry.
2187 If something goes wrong, give it another try.
2192 <title>Updating TeleDongle Firmware</title>
2194 Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
2195 firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
2197 <orderedlist inheritnum='inherit' numeration='arabic'>
2199 Find the 'programming cable' that you got as part of the starter
2200 kit, that has a red 8-pin MicroMaTch connector on one end and a
2201 red 4-pin MicroMaTch connector on the other end.
2204 Find the USB cable that you got as part of the starter kit, and
2205 plug the "mini" end in to the mating connector on TeleMetrum or TeleDongle.
2208 Take the 2 screws out of the TeleDongle case to get access
2209 to the circuit board.
2212 Plug the 8-pin end of the programming cable to the
2213 matching connector on the programmer, and the 4-pin end to the
2214 matching connector on the TeleDongle.
2215 Note that each MicroMaTch connector has an alignment pin that
2216 goes through a hole in the PC board when you have the cable
2220 Attach a battery to the TeleMetrum board if you're using one.
2223 Plug both the programmer and the TeleDongle into your computer's USB
2224 ports, and power up the programmer.
2227 Run AltosUI, and select 'Flash Image' from the File menu.
2230 Pick the programmer device from the list, identifying it as the
2234 Select the image you want put on the TeleDongle, which should have a
2235 name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
2236 in the default directory, if not you may have to poke around
2237 your system to find it.
2240 Make sure the configuration parameters are reasonable
2241 looking. If the serial number and/or RF configuration
2242 values aren't right, you'll need to change them. The TeleDongle
2243 serial number is on the "bottom" of the circuit board, and can
2244 usually be read through the translucent blue plastic case without
2245 needing to remove the board from the case.
2248 Hit the 'OK' button and the software should proceed to flash
2249 the TeleDongle with new firmware, showing a progress bar.
2252 Confirm that the TeleDongle board seems to have updated OK, which you
2253 can do by plugging in to it over USB and using a terminal program
2254 to connect to the board and issue the 'v' command to check
2255 the version, etc. Once you're happy, remove the programming cable
2256 and put the cover back on the TeleDongle.
2259 If something goes wrong, give it another try.
2263 Be careful removing the programming cable from the locking 8-pin
2264 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
2265 screwdriver or knife blade to gently pry the locking ears out
2266 slightly to extract the connector. We used a locking connector on
2267 TeleMetrum to help ensure that the cabling to companion boards
2268 used in a rocket don't ever come loose accidentally in flight.
2273 <title>Hardware Specifications</title>
2275 <title>TeleMetrum Specifications</title>
2279 Recording altimeter for model rocketry.
2284 Supports dual deployment (can fire 2 ejection charges).
2289 70cm ham-band transceiver for telemetry down-link.
2294 Barometric pressure sensor good to 45k feet MSL.
2299 1-axis high-g accelerometer for motor characterization, capable of
2300 +/- 50g using default part.
2305 On-board, integrated GPS receiver with 5Hz update rate capability.
2310 On-board 1 megabyte non-volatile memory for flight data storage.
2315 USB interface for battery charging, configuration, and data recovery.
2320 Fully integrated support for Li-Po rechargeable batteries.
2325 Uses Li-Po to fire e-matches, can be modified to support
2326 optional separate pyro battery if needed.
2331 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
2337 <title>TeleMini Specifications</title>
2341 Recording altimeter for model rocketry.
2346 Supports dual deployment (can fire 2 ejection charges).
2351 70cm ham-band transceiver for telemetry down-link.
2356 Barometric pressure sensor good to 45k feet MSL.
2361 On-board 5 kilobyte non-volatile memory for flight data storage.
2366 RF interface for configuration, and data recovery.
2371 Support for Li-Po rechargeable batteries, using an external charger.
2376 Uses Li-Po to fire e-matches, can be modified to support
2377 optional separate pyro battery if needed.
2382 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube.
2391 TeleMetrum seems to shut off when disconnected from the
2392 computer. Make sure the battery is adequately charged. Remember the
2393 unit will pull more power than the USB port can deliver before the
2394 GPS enters "locked" mode. The battery charges best when TeleMetrum
2398 It's impossible to stop the TeleDongle when it's in "p" mode, I have
2399 to unplug the USB cable? Make sure you have tried to "escape out" of
2400 this mode. If this doesn't work the reboot procedure for the
2401 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
2402 outgoing buffer IF your "escape out" ('~~') does not work.
2403 At this point using either 'ao-view' (or possibly
2404 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
2408 The amber LED (on the TeleMetrum) lights up when both
2409 battery and USB are connected. Does this mean it's charging?
2410 Yes, the yellow LED indicates the charging at the 'regular' rate.
2411 If the led is out but the unit is still plugged into a USB port,
2412 then the battery is being charged at a 'trickle' rate.
2415 There are no "dit-dah-dah-dit" sound or lights like the manual mentions?
2416 That's the "pad" mode. Weak batteries might be the problem.
2417 It is also possible that the TeleMetrum is horizontal and the output
2418 is instead a "dit-dit" meaning 'idle'. For TeleMini, it's possible that
2419 it received a command packet which would have left it in "pad" mode.
2422 How do I save flight data?
2423 Live telemetry is written to file(s) whenever AltosUI is connected
2424 to the TeleDongle. The file area defaults to ~/TeleMetrum
2425 but is easily changed using the menus in AltosUI. The files that
2426 are written end in '.telem'. The after-flight
2427 data-dumped files will end in .eeprom and represent continuous data
2428 unlike the .telem files that are subject to losses
2429 along the RF data path.
2430 See the above instructions on what and how to save the eeprom stored
2431 data after physically retrieving your altimeter. Make sure to save
2432 the on-board data after each flight; while the TeleMetrum can store
2433 multiple flights, you never know when you'll lose the altimeter...
2437 <title>Notes for Older Software</title>
2440 Before AltosUI was written, using Altus Metrum devices required
2441 some finesse with the Linux command line. There was a limited
2442 GUI tool, ao-view, which provided functionality similar to the
2443 Monitor Flight window in AltosUI, but everything else was a
2444 fairly 80's experience. This appendix includes documentation for
2445 using that software.
2449 Both TeleMetrum and TeleDongle can be directly communicated
2450 with using USB ports. The first thing you should try after getting
2451 both units plugged into to your computer's USB port(s) is to run
2452 'ao-list' from a terminal-window to see what port-device-name each
2453 device has been assigned by the operating system.
2454 You will need this information to access the devices via their
2455 respective on-board firmware and data using other command line
2456 programs in the AltOS software suite.
2459 TeleMini can be communicated with through a TeleDongle device
2460 over the radio link. When first booted, TeleMini listens for a
2461 TeleDongle device and if it receives a packet, it goes into
2462 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be
2463 launched. The easiest way to get it talking is to start the
2464 communication link on the TeleDongle and the power up the
2468 To access the device's firmware for configuration you need a terminal
2469 program such as you would use to talk to a modem. The software
2470 authors prefer using the program 'cu' which comes from the UUCP package
2471 on most Unix-like systems such as Linux. An example command line for
2472 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
2473 indicated from running the
2474 ao-list program. Another reasonable terminal program for Linux is
2475 'cutecom'. The default 'escape'
2476 character used by CU (i.e. the character you use to
2477 issue commands to cu itself instead of sending the command as input
2478 to the connected device) is a '~'. You will need this for use in
2479 only two different ways during normal operations. First is to exit
2480 the program by sending a '~.' which is called a 'escape-disconnect'
2481 and allows you to close-out from 'cu'. The
2482 second use will be outlined later.
2485 All of the Altus Metrum devices share the concept of a two level
2486 command set in their firmware.
2487 The first layer has several single letter commands. Once
2488 you are using 'cu' (or 'cutecom') sending (typing) a '?'
2489 returns a full list of these
2490 commands. The second level are configuration sub-commands accessed
2491 using the 'c' command, for
2492 instance typing 'c?' will give you this second level of commands
2493 (all of which require the
2494 letter 'c' to access). Please note that most configuration options
2495 are stored only in Flash memory; TeleDongle doesn't provide any storage
2496 for these options and so they'll all be lost when you unplug it.
2499 Try setting these configuration ('c' or second level menu) values. A good
2500 place to start is by setting your call sign. By default, the boards
2501 use 'N0CALL' which is cute, but not exactly legal!
2502 Spend a few minutes getting comfortable with the units, their
2503 firmware, and 'cu' (or possibly 'cutecom').
2504 For instance, try to send
2505 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
2506 Verify you can connect and disconnect from the units while in your
2507 terminal program by sending the escape-disconnect mentioned above.
2510 To set the radio frequency, use the 'c R' command to specify the
2511 radio transceiver configuration parameter. This parameter is computed
2512 using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
2513 the standard calibration reference frequency, 'S', (normally 434.550MHz):
2517 Round the result to the nearest integer value.
2518 As with all 'c' sub-commands, follow this with a 'c w' to write the
2519 change to the parameter block in the on-board flash on
2520 your altimeter board if you want the change to stay in place across reboots.
2523 To set the apogee delay, use the 'c d' command.
2524 As with all 'c' sub-commands, follow this with a 'c w' to write the
2525 change to the parameter block in the on-board DataFlash chip.
2528 To set the main deployment altitude, use the 'c m' command.
2529 As with all 'c' sub-commands, follow this with a 'c w' to write the
2530 change to the parameter block in the on-board DataFlash chip.
2533 To calibrate the radio frequency, connect the UHF antenna port to a
2534 frequency counter, set the board to 434.550MHz, and use the 'C'
2535 command to generate a CW carrier. Wait for the transmitter temperature
2536 to stabilize and the frequency to settle down.
2537 Then, divide 434.550 MHz by the
2538 measured frequency and multiply by the current radio cal value show
2539 in the 'c s' command. For an unprogrammed board, the default value
2540 is 1186611. Take the resulting integer and program it using the 'c f'
2541 command. Testing with the 'C' command again should show a carrier
2542 within a few tens of Hertz of the intended frequency.
2543 As with all 'c' sub-commands, follow this with a 'c w' to write the
2544 change to the parameter block in the on-board DataFlash chip.
2547 Note that the 'reboot' command, which is very useful on the altimeters,
2548 will likely just cause problems with the dongle. The *correct* way
2549 to reset the dongle is just to unplug and re-plug it.
2552 A fun thing to do at the launch site and something you can do while
2553 learning how to use these units is to play with the radio link access
2554 between an altimeter and the TeleDongle. Be aware that you *must* create
2555 some physical separation between the devices, otherwise the link will
2556 not function due to signal overload in the receivers in each device.
2559 Now might be a good time to take a break and read the rest of this
2560 manual, particularly about the two "modes" that the altimeters
2561 can be placed in. TeleMetrum uses the position of the device when booting
2562 up will determine whether the unit is in "pad" or "idle" mode. TeleMini
2563 enters "idle" mode when it receives a command packet within the first 5 seconds
2564 of being powered up, otherwise it enters "pad" mode.
2567 You can access an altimeter in idle mode from the TeleDongle's USB
2568 connection using the radio link
2569 by issuing a 'p' command to the TeleDongle. Practice connecting and
2570 disconnecting ('~~' while using 'cu') from the altimeter. If
2571 you cannot escape out of the "p" command, (by using a '~~' when in
2572 CU) then it is likely that your kernel has issues. Try a newer version.
2575 Using this radio link allows you to configure the altimeter, test
2576 fire e-matches and igniters from the flight line, check pyro-match
2577 continuity and so forth. You can leave the unit turned on while it
2578 is in 'idle mode' and then place the
2579 rocket vertically on the launch pad, walk away and then issue a
2580 reboot command. The altimeter will reboot and start sending data
2581 having changed to the "pad" mode. If the TeleDongle is not receiving
2582 this data, you can disconnect 'cu' from the TeleDongle using the
2583 procedures mentioned above and THEN connect to the TeleDongle from
2584 inside 'ao-view'. If this doesn't work, disconnect from the
2585 TeleDongle, unplug it, and try again after plugging it back in.
2588 In order to reduce the chance of accidental firing of pyrotechnic
2589 charges, the command to fire a charge is intentionally somewhat
2590 difficult to type, and the built-in help is slightly cryptic to
2591 prevent accidental echoing of characters from the help text back at
2592 the board from firing a charge. The command to fire the apogee
2593 drogue charge is 'i DoIt drogue' and the command to fire the main
2594 charge is 'i DoIt main'.
2597 On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
2598 and 'ao-view' will both auditorily announce and visually indicate
2600 Now you can launch knowing that you have a good data path and
2601 good satellite lock for flight data and recovery. Remember
2602 you MUST tell ao-view to connect to the TeleDongle explicitly in
2603 order for ao-view to be able to receive data.
2606 The altimeters provide RDF (radio direction finding) tones on
2607 the pad, during descent and after landing. These can be used to
2608 locate the rocket using a directional antenna; the signal
2609 strength providing an indication of the direction from receiver to rocket.
2612 TeleMetrum also provides GPS tracking data, which can further simplify
2613 locating the rocket once it has landed. (The last good GPS data
2614 received before touch-down will be on the data screen of 'ao-view'.)
2617 Once you have recovered the rocket you can download the eeprom
2618 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
2619 either a USB cable or over the radio link using TeleDongle.
2620 And by following the man page for 'ao-postflight' you can create
2621 various data output reports, graphs, and even KML data to see the
2622 flight trajectory in Google-earth. (Moving the viewing angle making
2623 sure to connect the yellow lines while in Google-earth is the proper
2627 As for ao-view.... some things are in the menu but don't do anything
2628 very useful. The developers have stopped working on ao-view to focus
2629 on a new, cross-platform ground station program. So ao-view may or
2630 may not be updated in the future. Mostly you just use
2631 the Log and Device menus. It has a wonderful display of the incoming
2632 flight data and I am sure you will enjoy what it has to say to you
2633 once you enable the voice output!
2637 <title>Drill Templates</title>
2639 These images, when printed, provide precise templates for the
2640 mounting holes in Altus Metrum flight computers
2643 <title>TeleMetrum template</title>
2645 TeleMetrum has overall dimensions of 1.000 x 2.750 inches, and the
2646 mounting holes are sized for use with 4-40 or M3 screws.
2648 <mediaobject id="TeleMetrumTemplate">
2650 <imagedata format="SVG" fileref="telemetrum.svg"/>
2655 <title>TeleMini template</title>
2657 TeleMini has overall dimensions of 0.500 x 1.500 inches, and the
2658 mounting holes are sized for use with 2-56 or M2 screws.
2660 <mediaobject id="TeleMiniTemplate">
2662 <imagedata format="SVG" fileref="telemini.svg"/>
2668 <title>Calibration</title>
2670 There are only two calibrations required for a TeleMetrum board, and
2671 only one for TeleDongle and TeleMini. All boards are shipped from
2672 the factory pre-calibrated, but the procedures are documented here
2673 in case they are ever needed. Re-calibration is not supported by
2674 AltosUI, you must connect to the board with a serial terminal program
2675 and interact directly with the on-board command interpreter to effect
2679 <title>Radio Frequency</title>
2681 The radio frequency is synthesized from a clock based on the 48 MHz
2682 crystal on the board. The actual frequency of this oscillator
2683 must be measured to generate a calibration constant. While our
2685 bandwidth is wide enough to allow boards to communicate even when
2686 their oscillators are not on exactly the same frequency, performance
2687 is best when they are closely matched.
2688 Radio frequency calibration requires a calibrated frequency counter.
2689 Fortunately, once set, the variation in frequency due to aging and
2690 temperature changes is small enough that re-calibration by customers
2691 should generally not be required.
2694 To calibrate the radio frequency, connect the UHF antenna port to a
2695 frequency counter, set the board to 434.550MHz, and use the 'C'
2696 command in the on-board command interpreter to generate a CW
2697 carrier. For TeleMetrum, this is best done over USB. For TeleMini,
2698 note that the only way to escape the 'C' command is via power cycle
2699 since the board will no longer be listening for commands once it
2700 starts generating a CW carrier.
2703 Wait for the transmitter temperature to stabilize and the frequency
2704 to settle down. Then, divide 434.550 MHz by the
2705 measured frequency and multiply by the current radio cal value show
2706 in the 'c s' command. For an unprogrammed board, the default value
2707 is 1186611. Take the resulting integer and program it using the 'c f'
2708 command. Testing with the 'C' command again should show a carrier
2709 within a few tens of Hertz of the intended frequency.
2710 As with all 'c' sub-commands, follow this with a 'c w' to write the
2711 change to the parameter block in the on-board DataFlash chip.
2714 Note that any time you re-do the radio frequency calibration, the
2715 radio frequency is reset to the default 434.550 Mhz. If you want
2716 to use another frequency, you will have to set that again after
2717 calibration is completed.
2721 <title>TeleMetrum Accelerometer</title>
2723 The TeleMetrum accelerometer we use has its own 5 volt power
2725 the output must be passed through a resistive voltage divider to match
2726 the input of our 3.3 volt ADC. This means that unlike the barometric
2727 sensor, the output of the acceleration sensor is not ratio-metric to
2728 the ADC converter, and calibration is required. Explicitly
2729 calibrating the accelerometers also allows us to load any device
2730 from a Freescale family that includes at least +/- 40g, 50g, 100g,
2731 and 200g parts. Using gravity,
2732 a simple 2-point calibration yields acceptable results capturing both
2733 the different sensitivities and ranges of the different accelerometer
2734 parts and any variation in power supply voltages or resistor values
2735 in the divider network.
2738 To calibrate the acceleration sensor, use the 'c a 0' command. You
2739 will be prompted to orient the board vertically with the UHF antenna
2740 up and press a key, then to orient the board vertically with the
2741 UHF antenna down and press a key. Note that the accuracy of this
2742 calibration depends primarily on how perfectly vertical and still
2743 the board is held during the cal process. As with all 'c'
2744 sub-commands, follow this with a 'c w' to write the
2745 change to the parameter block in the on-board DataFlash chip.
2748 The +1g and -1g calibration points are included in each telemetry
2749 frame and are part of the header stored in onboard flash to be
2750 downloaded after flight. We always store and return raw ADC
2751 samples for each sensor... so nothing is permanently "lost" or
2752 "damaged" if the calibration is poor.
2755 In the unlikely event an accel cal goes badly, it is possible
2756 that TeleMetrum may always come up in 'pad mode' and as such not be
2757 listening to either the USB or radio link. If that happens,
2758 there is a special hook in the firmware to force the board back
2759 in to 'idle mode' so you can re-do the cal. To use this hook, you
2760 just need to ground the SPI clock pin at power-on. This pin is
2761 available as pin 2 on the 8-pin companion connector, and pin 1 is
2762 ground. So either carefully install a fine-gauge wire jumper
2763 between the two pins closest to the index hole end of the 8-pin
2764 connector, or plug in the programming cable to the 8-pin connector
2765 and use a small screwdriver or similar to short the two pins closest
2766 to the index post on the 4-pin end of the programming cable, and
2767 power up the board. It should come up in 'idle mode' (two beeps),
2773 xmlns:xi="http://www.w3.org/2001/XInclude">
2774 <title>Release Notes</title>
2775 <simplesect><title>Version 1.2</title><xi:include href="release-notes-1.2.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2776 <simplesect><title>Version 1.1.1</title><xi:include href="release-notes-1.1.1.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2777 <simplesect><title>Version 1.1</title><xi:include href="release-notes-1.1.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2778 <simplesect><title>Version 1.0.1</title><xi:include href="release-notes-1.0.1.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2779 <simplesect><title>Version 0.9.2</title><xi:include href="release-notes-0.9.2.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2780 <simplesect><title>Version 0.9</title><xi:include href="release-notes-0.9.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2781 <simplesect><title>Version 0.8</title><xi:include href="release-notes-0.8.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2782 <simplesect><title>Version 0.7.1</title><xi:include href="release-notes-0.7.1.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2786 <!-- LocalWords: Altusmetrum
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