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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>1.3</revnumber>
40 <date>12 November 2013</date>
42 Updated for software version 1.3. Version 1.3 adds support
43 for TeleMega, TeleMetrum v2.0, TeleMini v2.0 and EasyMini
44 and fixes bugs in AltosUI and the AltOS firmware.
48 <revnumber>1.2.1</revnumber>
49 <date>21 May 2013</date>
51 Updated for software version 1.2. Version 1.2 adds support
52 for TeleBT and AltosDroid. It also adds a few minor features
53 and fixes bugs in AltosUI and the AltOS firmware.
57 <revnumber>1.2</revnumber>
58 <date>18 April 2013</date>
60 Updated for software version 1.2. Version 1.2 adds support
61 for MicroPeak and the MicroPeak USB interface.
65 <revnumber>1.1.1</revnumber>
66 <date>16 September 2012</date>
68 Updated for software version 1.1.1 Version 1.1.1 fixes a few
69 bugs found in version 1.1.
73 <revnumber>1.1</revnumber>
74 <date>13 September 2012</date>
76 Updated for software version 1.1. Version 1.1 has new
77 features but is otherwise compatible with version 1.0.
81 <revnumber>1.0</revnumber>
82 <date>24 August 2011</date>
84 Updated for software version 1.0. Note that 1.0 represents a
85 telemetry format change, meaning both ends of a link
86 (TeleMetrum/TeleMini and TeleDongle) must be updated or
87 communications will fail.
91 <revnumber>0.9</revnumber>
92 <date>18 January 2011</date>
94 Updated for software version 0.9. Note that 0.9 represents a
95 telemetry format change, meaning both ends of a link (TeleMetrum and
96 TeleDongle) must be updated or communications will fail.
100 <revnumber>0.8</revnumber>
101 <date>24 November 2010</date>
102 <revremark>Updated for software version 0.8 </revremark>
108 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing "The
109 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
110 Kit" which formed the basis of the original Getting Started chapter
111 in this manual. Bob was one of our first customers for a production
112 TeleMetrum, and his continued enthusiasm and contributions
113 are immensely gratifying and highly appreciated!
116 And thanks to Anthony (AJ) Towns for major contributions including
117 the AltosUI graphing and site map code and associated documentation.
118 Free software means that our customers and friends can become our
119 collaborators, and we certainly appreciate this level of
123 Have fun using these products, and we hope to meet all of you
124 out on the rocket flight line somewhere.
127 NAR #87103, TRA #12201
129 Keith Packard, KD7SQG
130 NAR #88757, TRA #12200
135 <title>Introduction and Overview</title>
137 Welcome to the Altus Metrum community! Our circuits and software reflect
138 our passion for both hobby rocketry and Free Software. We hope their
139 capabilities and performance will delight you in every way, but by
140 releasing all of our hardware and software designs under open licenses,
141 we also hope to empower you to take as active a role in our collective
145 The first device created for our community was TeleMetrum, a dual
146 deploy altimeter with fully integrated GPS and radio telemetry
147 as standard features, and a "companion interface" that will
148 support optional capabilities in the future. The latest version
149 of TeleMetrum, v2.0, has all of the same features but with
150 improved sensors and radio to offer increased performance.
153 Our second device was TeleMini, a dual deploy altimeter with
154 radio telemetry and radio direction finding. The first version
155 of this device was only 13mm by 38mm (½ inch by 1½ inches) and
156 could fit easily in an 18mm air-frame. The latest version, v2.0,
157 includes a beeper, USB data download and extended on-board
158 flight logging, along with an improved barometric sensor.
161 TeleMega is our most sophisticated device, including six pyro
162 channels (four of which are fully programmable), integrated GPS,
163 integrated gyroscopes for staging/air-start inhibit and high
164 performance telemetry.
167 EasyMini is a dual-deploy altimeter with logging and built-in
171 TeleDongle was our first ground station, providing a USB to RF
172 interfaces for communicating with the altimeters. Combined with
173 your choice of antenna and notebook computer, TeleDongle and our
174 associated user interface software form a complete ground
175 station capable of logging and displaying in-flight telemetry,
176 aiding rocket recovery, then processing and archiving flight
177 data for analysis and review.
180 For a slightly more portable ground station experience that also
181 provides direct rocket recovery support, TeleBT offers flight
182 monitoring and data logging using a Bluetooth connection between
183 the receiver and an Android device that has the Altos Droid
184 application installed from the Google Play store.
187 More products will be added to the Altus Metrum family over time, and
188 we currently envision that this will be a single, comprehensive manual
189 for the entire product family.
193 <title>Getting Started</title>
195 The first thing to do after you check the inventory of parts in your
196 "starter kit" is to charge the battery.
199 For TeleMetrum and TeleMega, the battery can be charged by plugging it into the
200 corresponding socket of the device and then using the USB
201 cable to plug the flight computer into your computer's USB socket. The
202 on-board circuitry will charge the battery whenever it is plugged
203 in, because the on-off switch does NOT control the
207 On TeleMetrum v1 boards, when the GPS chip is initially
208 searching for satellites, TeleMetrum will consume more current
209 than it can pull from the USB port, so the battery must be
210 attached in order to get satellite lock. Once GPS is locked,
211 the current consumption goes back down enough to enable charging
212 while running. So it's a good idea to fully charge the battery
213 as your first item of business so there is no issue getting and
214 maintaining satellite lock. The yellow charge indicator led
215 will go out when the battery is nearly full and the charger goes
216 to trickle charge. It can take several hours to fully recharge a
217 deeply discharged battery.
220 TeleMetrum v2.0 and TeleMega use a higher power battery charger,
221 allowing them to charge the battery while running the board at
222 maximum power. When the battery is charging, or when the board
223 is consuming a lot of power, the red LED will be lit. When the
224 battery is fully charged, the green LED will be lit. When the
225 battery is damaged or missing, both LEDs will be lit, which
229 The Lithium Polymer TeleMini and EasyMini battery can be charged by
230 disconnecting it from the board and plugging it into a
231 standalone battery charger such as the LipoCharger product
232 included in TeleMini Starter Kits, and connecting that via a USB
233 cable to a laptop or other USB power source.
236 You can also choose to use another battery with TeleMini v2.0
237 and EasyMini, anything supplying between 4 and 12 volts should
238 work fine (like a standard 9V battery), but if you are planning
239 to fire pyro charges, ground testing is required to verify that
240 the battery supplies enough current.
243 The other active device in the starter kit is the TeleDongle USB to
244 RF interface. If you plug it in to your Mac or Linux computer it should
245 "just work", showing up as a serial port device. Windows systems need
246 driver information that is part of the AltOS download to know that the
247 existing USB modem driver will work. We therefore recommend installing
248 our software before plugging in TeleDongle if you are using a Windows
249 computer. If you are using Linux and are having problems, try moving
250 to a fresher kernel (2.6.33 or newer), as the USB serial driver had
251 ugly bugs in some earlier versions.
254 Next you should obtain and install the AltOS software. These
255 include the AltosUI ground station program, current firmware
256 images for all of the hardware, and a number of standalone
257 utilities that are rarely needed. Pre-built binary packages are
258 available for Linux, Microsoft Windows, and recent MacOSX
259 versions. Full source code and build instructions are also
260 available. The latest version may always be downloaded from
261 <ulink url="http://altusmetrum.org/AltOS"/>.
264 If you're using a TeleBT instead of the TeleDongle, you'll want
265 to go install the Altos Droid application from the Google Play
266 store. You don't need a data plan to use Altos Droid, but
267 without network access, the Map view will be less useful as it
268 won't contain any map data. You can also use TeleBT connected
269 over USB with your laptop computer; it acts exactly like a
270 TeleDongle. Anywhere this manual talks about TeleDongle, you can
271 also read that as 'and TeleBT when connected via USB'.
275 <title>Handling Precautions</title>
277 All Altus Metrum products are sophisticated electronic devices.
278 When handled gently and properly installed in an air-frame, they
279 will deliver impressive results. However, as with all electronic
280 devices, there are some precautions you must take.
283 The Lithium Polymer rechargeable batteries have an
284 extraordinary power density. This is great because we can fly with
285 much less battery mass than if we used alkaline batteries or previous
286 generation rechargeable batteries... but if they are punctured
287 or their leads are allowed to short, they can and will release their
289 Thus we recommend that you take some care when handling our batteries
290 and consider giving them some extra protection in your air-frame. We
291 often wrap them in suitable scraps of closed-cell packing foam before
292 strapping them down, for example.
295 The barometric sensors used on all of our flight computers are
296 sensitive to sunlight. In normal mounting situations, the baro sensor
297 and all of the other surface mount components
298 are "down" towards whatever the underlying mounting surface is, so
299 this is not normally a problem. Please consider this, though, when
300 designing an installation, for example, in an air-frame with a
301 see-through plastic payload bay. It is particularly important to
302 consider this with TeleMini v1.0, both because the baro sensor is on the
303 "top" of the board, and because many model rockets with payload bays
304 use clear plastic for the payload bay! Replacing these with an opaque
305 cardboard tube, painting them, or wrapping them with a layer of masking
306 tape are all reasonable approaches to keep the sensor out of direct
310 The barometric sensor sampling port must be able to "breathe",
311 both by not being covered by foam or tape or other materials that might
312 directly block the hole on the top of the sensor, and also by having a
313 suitable static vent to outside air.
316 As with all other rocketry electronics, Altus Metrum altimeters must
317 be protected from exposure to corrosive motor exhaust and ejection
322 <title>Hardware Overview</title>
324 TeleMetrum is a 1 inch by 2¾ inch circuit board. It was designed to
325 fit inside coupler for 29mm air-frame tubing, but using it in a tube that
326 small in diameter may require some creativity in mounting and wiring
327 to succeed! The presence of an accelerometer means TeleMetrum should
328 be aligned along the flight axis of the airframe, and by default the 1/4
329 wave UHF wire antenna should be on the nose-cone end of the board. The
330 antenna wire is about 7 inches long, and wiring for a power switch and
331 the e-matches for apogee and main ejection charges depart from the
332 fin can end of the board, meaning an ideal "simple" avionics
333 bay for TeleMetrum should have at least 10 inches of interior length.
336 TeleMini v1.0 is a ½ inch by 1½ inch circuit board. It was designed to
337 fit inside an 18mm air-frame tube, but using it in a tube that
338 small in diameter may require some creativity in mounting and wiring
339 to succeed! Since there is no accelerometer, TeleMini can be mounted
340 in any convenient orientation. The default ¼
341 wave UHF wire antenna attached to the center of one end of
342 the board is about 7 inches long, and wiring for a power switch and
343 the e-matches for apogee and main ejection charges depart from the
344 other end of the board, meaning an ideal "simple" avionics
345 bay for TeleMini should have at least 9 inches of interior length.
348 TeleMini v2.0 and EasyMini are both built on a 0.8 inch by 1½
349 inch circuit board. They're designed to fit in a 24mm coupler
350 tube. TeleMini has an antenna, which must be run straight out
351 fro the board. Bending or folding it will dramatically reduce RF
352 performance. For smaller rockets, it's often best to drill a
353 hole in the bulkhead forward of TeleMini and run the antenna
354 wire through that and alongside any recovery components
355 there. Be careful to seal the hole to prevent ejection gasses
356 from passing through the hole and damaging the electronics.
359 TeleMega is a 1¼ inch by 3¼ inch circuit board. It was
360 designed to easily fit in a 38mm coupler. Like TeleMetrum,
361 TeleMega has an accelerometer and so it must be mounted so that
362 the board is aligned with the flight axis. It can be mounted
363 either antenna up or down.
366 A typical installation involves attaching
367 only a suitable battery, a single pole switch for
368 power on/off, and two pairs of wires connecting e-matches for the
369 apogee and main ejection charges. All Altus Metrum products are
370 designed for use with single-cell batteries with 3.7 volts
371 nominal. TeleMini v2.0 and EasyMini may also be used with other
372 batteries as long as they supply between 4 and 12 volts.
375 The battery connectors are a standard 2-pin JST connector and
376 match batteries sold by Spark Fun. These batteries are
377 single-cell Lithium Polymer batteries that nominally provide 3.7
378 volts. Other vendors sell similar batteries for RC aircraft
379 using mating connectors, however the polarity for those is
380 generally reversed from the batteries used by Altus Metrum
381 products. In particular, the Tenergy batteries supplied for use
382 in Featherweight flight computers are not compatible with Altus
383 Metrum flight computers or battery chargers. <emphasis>Check
384 polarity and voltage before connecting any battery not purchased
385 from Altus Metrum or Spark Fun.</emphasis>
388 By default, we use the unregulated output of the battery directly
389 to fire ejection charges. This works marvelously with standard
390 low-current e-matches like the J-Tek from MJG Technologies, and with
391 Quest Q2G2 igniters. However, if you want or need to use a separate
392 pyro battery, check out the "External Pyro Battery" section in this
393 manual for instructions on how to wire that up. The altimeters are
394 designed to work with an external pyro battery of no more than 15 volts.
397 Ejection charges are wired directly to the screw terminal block
398 at the aft end of the altimeter. You'll need a very small straight
399 blade screwdriver for these screws, such as you might find in a
400 jeweler's screwdriver set.
403 Except for TeleMini v1.0, the flight computers also use the
404 screw terminal block for the power switch leads. On TeleMini v1.0,
405 the power switch leads are soldered directly to the board and
406 can be connected directly to a switch.
409 For most air-frames, the integrated antennas are more than
410 adequate. However, if you are installing in a carbon-fiber or
411 metal electronics bay which is opaque to RF signals, you may need to
412 use off-board external antennas instead. In this case, you can
413 order an altimeter with an SMA connector for the UHF antenna
414 connection, and, on TeleMetrum v1, you can unplug the integrated GPS
415 antenna and select an appropriate off-board GPS antenna with
416 cable terminating in a U.FL connector.
420 <title>System Operation</title>
422 <title>Firmware Modes </title>
424 The AltOS firmware build for the altimeters has two
425 fundamental modes, "idle" and "flight". Which of these modes
426 the firmware operates in is determined at start up time. For
427 TeleMetrum, the mode is controlled by the orientation of the
428 rocket (well, actually the board, of course...) at the time
429 power is switched on. If the rocket is "nose up", then
430 TeleMetrum assumes it's on a rail or rod being prepared for
431 launch, so the firmware chooses flight mode. However, if the
432 rocket is more or less horizontal, the firmware instead enters
433 idle mode. Since TeleMini v2.0 and EasyMini don't have an
434 accelerometer we can use to determine orientation, "idle" mode
435 is selected if the board is connected via USB to a computer,
436 otherwise the board enters "flight" mode. TeleMini v1.0
437 selects "idle" mode if it receives a command packet within the
438 first five seconds of operation.
441 At power on, you will hear three beeps or see three flashes
442 ("S" in Morse code for start up) and then a pause while
443 the altimeter completes initialization and self test, and decides
444 which mode to enter next.
447 In flight or "pad" mode, the altimeter engages the flight
448 state machine, goes into transmit-only mode to
449 send telemetry, and waits for launch to be detected.
450 Flight mode is indicated by an "di-dah-dah-dit" ("P" for pad)
451 on the beeper or lights, followed by beeps or flashes
452 indicating the state of the pyrotechnic igniter continuity.
453 One beep/flash indicates apogee continuity, two beeps/flashes
454 indicate main continuity, three beeps/flashes indicate both
455 apogee and main continuity, and one longer "brap" sound or
456 rapidly alternating lights indicates no continuity. For a
457 dual deploy flight, make sure you're getting three beeps or
458 flashes before launching! For apogee-only or motor eject
459 flights, do what makes sense.
462 If idle mode is entered, you will hear an audible "di-dit" or
463 see two short flashes ("I" for idle), and the flight state
464 machine is disengaged, thus no ejection charges will fire.
465 The altimeters also listen for the radio link when in idle
466 mode for requests sent via TeleDongle. Commands can be issued
467 in idle mode over either USB or the radio link
468 equivalently. TeleMini v1.0 only has the radio link. Idle
469 mode is useful for configuring the altimeter, for extracting
470 data from the on-board storage chip after flight, and for
471 ground testing pyro charges.
474 One "neat trick" of particular value when TeleMetrum or TeleMega are used with
475 very large air-frames, is that you can power the board up while the
476 rocket is horizontal, such that it comes up in idle mode. Then you can
477 raise the air-frame to launch position, and issue a 'reset' command
478 via TeleDongle over the radio link to cause the altimeter to reboot and
479 come up in flight mode. This is much safer than standing on the top
480 step of a rickety step-ladder or hanging off the side of a launch
481 tower with a screw-driver trying to turn on your avionics before
485 TeleMini v1.0 is configured solely via the radio link. Of course, that
486 means you need to know the TeleMini radio configuration values
487 or you won't be able to communicate with it. For situations
488 when you don't have the radio configuration values, TeleMini v1.0
489 offers an 'emergency recovery' mode. In this mode, TeleMini is
490 configured as follows:
493 Sets the radio frequency to 434.550MHz
496 Sets the radio calibration back to the factory value.
499 Sets the callsign to N0CALL
502 Does not go to 'pad' mode after five seconds.
507 To get into 'emergency recovery' mode, first find the row of
508 four small holes opposite the switch wiring. Using a short
509 piece of small gauge wire, connect the outer two holes
510 together, then power TeleMini up. Once the red LED is lit,
511 disconnect the wire and the board should signal that it's in
512 'idle' mode after the initial five second startup period.
518 TeleMetrum and TeleMega include a complete GPS receiver. A
519 complete explanation of how GPS works is beyond the scope of
520 this manual, but the bottom line is that the GPS receiver
521 needs to lock onto at least four satellites to obtain a solid
522 3 dimensional position fix and know what time it is.
525 The flight computers provide backup power to the GPS chip any time a
526 battery is connected. This allows the receiver to "warm start" on
527 the launch rail much faster than if every power-on were a GPS
528 "cold start". In typical operations, powering up
529 on the flight line in idle mode while performing final air-frame
530 preparation will be sufficient to allow the GPS receiver to cold
531 start and acquire lock. Then the board can be powered down during
532 RSO review and installation on a launch rod or rail. When the board
533 is turned back on, the GPS system should lock very quickly, typically
534 long before igniter installation and return to the flight line are
539 <title>Controlling An Altimeter Over The Radio Link</title>
541 One of the unique features of the Altus Metrum system is the
542 ability to create a two way command link between TeleDongle
543 and an altimeter using the digital radio transceivers
544 built into each device. This allows you to interact with the
545 altimeter from afar, as if it were directly connected to the
549 Any operation which can be performed with a flight computer can
550 either be done with the device directly connected to the
551 computer via the USB cable, or through the radio
552 link. TeleMini v1.0 doesn't provide a USB connector and so it is
553 always communicated with over radio. Select the appropriate
554 TeleDongle device when the list of devices is presented and
555 AltosUI will interact with an altimeter over the radio link.
558 One oddity in the current interface is how AltosUI selects the
559 frequency for radio communications. Instead of providing
560 an interface to specifically configure the frequency, it uses
561 whatever frequency was most recently selected for the target
562 TeleDongle device in Monitor Flight mode. If you haven't ever
563 used that mode with the TeleDongle in question, select the
564 Monitor Flight button from the top level UI, and pick the
565 appropriate TeleDongle device. Once the flight monitoring
566 window is open, select the desired frequency and then close it
567 down again. All radio communications will now use that frequency.
572 Save Flight Data—Recover flight data from the rocket without
578 Configure altimeter apogee delays, main deploy heights
579 and additional pyro event conditions
580 to respond to changing launch conditions. You can also
581 'reboot' the altimeter. Use this to remotely enable the
582 flight computer by turning TeleMetrum or TeleMega on in "idle" mode,
583 then once the air-frame is oriented for launch, you can
584 reboot the altimeter and have it restart in pad mode
585 without having to climb the scary ladder.
590 Fire Igniters—Test your deployment charges without snaking
591 wires out through holes in the air-frame. Simply assemble the
592 rocket as if for flight with the apogee and main charges
593 loaded, then remotely command the altimeter to fire the
599 Operation over the radio link for configuring an altimeter, ground
600 testing igniters, and so forth uses the same RF frequencies as flight
601 telemetry. To configure the desired TeleDongle frequency, select
602 the monitor flight tab, then use the frequency selector and
603 close the window before performing other desired radio operations.
606 The flight computers only enable radio commanding in 'idle' mode.
607 TeleMetrum and TeleMega use the accelerometer to detect which orientation they
608 start up in, so make sure you have the flight computer lying horizontally when you turn
609 it on. Otherwise, it will start in 'pad' mode ready for
610 flight, and will not be listening for command packets from TeleDongle.
613 TeleMini listens for a command packet for five seconds after
614 first being turned on, if it doesn't hear anything, it enters
615 'pad' mode, ready for flight and will no longer listen for
616 command packets. The easiest way to connect to TeleMini is to
617 initiate the command and select the TeleDongle device. At this
618 point, the TeleDongle will be attempting to communicate with
619 the TeleMini. Now turn TeleMini on, and it should immediately
620 start communicating with the TeleDongle and the desired
621 operation can be performed.
624 You can monitor the operation of the radio link by watching the
625 lights on the devices. The red LED will flash each time a packet
626 is transmitted, while the green LED will light up on TeleDongle when
627 it is waiting to receive a packet from the altimeter.
631 <title>Ground Testing </title>
633 An important aspect of preparing a rocket using electronic deployment
634 for flight is ground testing the recovery system. Thanks
635 to the bi-directional radio link central to the Altus Metrum system,
636 this can be accomplished in a TeleMega, TeleMetrum or TeleMini equipped rocket
637 with less work than you may be accustomed to with other systems. It
641 Just prep the rocket for flight, then power up the altimeter
642 in "idle" mode (placing air-frame horizontal for TeleMetrum or TeleMega, or
643 selecting the Configure Altimeter tab for TeleMini). This will cause
644 the firmware to go into "idle" mode, in which the normal flight
645 state machine is disabled and charges will not fire without
646 manual command. You can now command the altimeter to fire the apogee
647 or main charges from a safe distance using your computer and
648 TeleDongle and the Fire Igniter tab to complete ejection testing.
652 <title>Radio Link </title>
654 The chip our boards are based on incorporates an RF transceiver, but
655 it's not a full duplex system... each end can only be transmitting or
656 receiving at any given moment. So we had to decide how to manage the
660 By design, the altimeter firmware listens for the radio link when
661 it's in "idle mode", which
662 allows us to use the radio link to configure the rocket, do things like
663 ejection tests, and extract data after a flight without having to
664 crack open the air-frame. However, when the board is in "flight
665 mode", the altimeter only
666 transmits and doesn't listen at all. That's because we want to put
667 ultimate priority on event detection and getting telemetry out of
669 the radio in case the rocket crashes and we aren't able to extract
673 We don't generally use a 'normal packet radio' mode like APRS because they're
674 just too inefficient. The GFSK modulation we use is FSK with the
675 base-band pulses passed through a
676 Gaussian filter before they go into the modulator to limit the
677 transmitted bandwidth. When combined with the hardware forward error
678 correction support in the cc1111 chip, this allows us to have a very
679 robust 38.4 kilobit data link with only 10 milliwatts of transmit
680 power, a whip antenna in the rocket, and a hand-held Yagi on the
681 ground. We've had flights to above 21k feet AGL with great reception,
682 and calculations suggest we should be good to well over 40k feet AGL
683 with a 5-element yagi on the ground. We hope to fly boards to higher
684 altitudes over time, and would of course appreciate customer feedback
685 on performance in higher altitude flights!
688 However, TeleMetrum v2.0 and TeleMega can send APRS if
689 desired, the interval between APRS packets can be
690 configured. As each APRS packet takes a full second to
691 transmit, we recommend an interval of at least 5 seconds.
695 <title>Configurable Parameters</title>
697 Configuring an Altus Metrum altimeter for flight is very
698 simple. Even on our baro-only TeleMini and EasyMini boards, the use of a Kalman
699 filter means there is no need to set a "mach delay". The few
700 configurable parameters can all be set using AltosUI over USB or
701 or radio link via TeleDongle.
704 <title>Radio Frequency</title>
706 Altus Metrum boards support radio frequencies in the 70cm
707 band. By default, the configuration interface provides a
708 list of 10 "standard" frequencies in 100kHz channels starting at
709 434.550MHz. However, the firmware supports use of
710 any 50kHz multiple within the 70cm band. At any given
711 launch, we highly recommend coordinating when and by whom each
712 frequency will be used to avoid interference. And of course, both
713 altimeter and TeleDongle must be configured to the same
714 frequency to successfully communicate with each other.
718 <title>Apogee Delay</title>
720 Apogee delay is the number of seconds after the altimeter detects flight
721 apogee that the drogue charge should be fired. In most cases, this
722 should be left at the default of 0. However, if you are flying
723 redundant electronics such as for an L3 certification, you may wish
724 to set one of your altimeters to a positive delay so that both
725 primary and backup pyrotechnic charges do not fire simultaneously.
728 The Altus Metrum apogee detection algorithm fires exactly at
729 apogee. If you are also flying an altimeter like the
730 PerfectFlite MAWD, which only supports selecting 0 or 1
731 seconds of apogee delay, you may wish to set the MAWD to 0
732 seconds delay and set the TeleMetrum to fire your backup 2
733 or 3 seconds later to avoid any chance of both charges
734 firing simultaneously. We've flown several air-frames this
735 way quite happily, including Keith's successful L3 cert.
739 <title>Main Deployment Altitude</title>
741 By default, the altimeter will fire the main deployment charge at an
742 elevation of 250 meters (about 820 feet) above ground. We think this
743 is a good elevation for most air-frames, but feel free to change this
744 to suit. In particular, if you are flying two altimeters, you may
746 deployment elevation for the backup altimeter to be something lower
747 than the primary so that both pyrotechnic charges don't fire
752 <title>Maximum Flight Log</title>
754 TeleMetrum version 1.1 and 1.2 have 2MB of on-board flash storage,
755 enough to hold over 40 minutes of data at full data rate
756 (100 samples/second). TeleMetrum 1.0 has 1MB of on-board
757 storage. As data are stored at a reduced rate during descent
758 (10 samples/second), there's plenty of space to store many
759 flights worth of data.
762 TeleMetrum v2.0 and TeleMega have 8MB of on-board flash stroage, enough to hold
765 The on-board flash is partitioned into separate flight logs,
766 each of a fixed maximum size. Increase the maximum size of
767 each log and you reduce the number of flights that can be
768 stored. Decrease the size and TeleMetrum can store more
772 All of the configuration data is also stored in the flash
773 memory, which consumes 64kB on TeleMetrum v1.1/v1.2 and 256B on
774 TeleMetrum v1.0. This configuration space is not available
775 for storing flight log data.
778 To compute the amount of space needed for a single flight,
779 you can multiply the expected ascent time (in seconds) by
780 800, multiply the expected descent time (in seconds) by 80
781 and add the two together. That will slightly under-estimate
782 the storage (in bytes) needed for the flight. For instance,
783 a flight spending 20 seconds in ascent and 150 seconds in
784 descent will take about (20 * 800) + (150 * 80) = 28000
785 bytes of storage. You could store dozens of these flights in
789 The default size, 192kB, allows for 10 flights of storage on
790 TeleMetrum v1.1/v1.2 and 5 flights on TeleMetrum v1.0. This
791 ensures that you won't need to erase the memory before
792 flying each time while still allowing more than sufficient
793 storage for each flight.
796 As TeleMini does not contain an accelerometer, it stores
797 data at 10 samples per second during ascent and one sample
798 per second during descent. Each sample is a two byte reading
799 from the barometer. These are stored in 5kB of
800 on-chip flash memory which can hold 256 seconds at the
801 ascent rate or 2560 seconds at the descent rate. Because of
802 the limited storage, TeleMini cannot hold data for more than
803 one flight, and so must be erased after each flight or it
804 will not capture data for subsequent flights.
808 <title>Ignite Mode</title>
810 Instead of firing one charge at apogee and another charge at
811 a fixed height above the ground, you can configure the
812 altimeter to fire both at apogee or both during
813 descent. This was added to support an airframe that has two
814 TeleMetrum computers, one in the fin can and one in the
818 Providing the ability to use both igniters for apogee or
819 main allows some level of redundancy without needing two
820 flight computers. In Redundant Apogee or Redundant Main
821 mode, the two charges will be fired two seconds apart.
825 <title>Pad Orientation</title>
827 TeleMetrum measures acceleration along the axis of the
828 board. Which way the board is oriented affects the sign of
829 the acceleration value. Instead of trying to guess which way
830 the board is mounted in the air frame, TeleMetrum must be
831 explicitly configured for either Antenna Up or Antenna
832 Down. The default, Antenna Up, expects the end of the
833 TeleMetrum board connected to the 70cm antenna to be nearest
834 the nose of the rocket, with the end containing the screw
835 terminals nearest the tail.
843 <title>AltosUI</title>
845 The AltosUI program provides a graphical user interface for
846 interacting with the Altus Metrum product family, including
847 TeleMetrum, TeleMini and TeleDongle. AltosUI can monitor telemetry data,
848 configure TeleMetrum, TeleMini and TeleDongle devices and many other
849 tasks. The primary interface window provides a selection of
850 buttons, one for each major activity in the system. This manual
851 is split into chapters, each of which documents one of the tasks
852 provided from the top-level toolbar.
855 <title>Monitor Flight</title>
856 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
858 Selecting this item brings up a dialog box listing all of the
859 connected TeleDongle devices. When you choose one of these,
860 AltosUI will create a window to display telemetry data as
861 received by the selected TeleDongle device.
864 All telemetry data received are automatically recorded in
865 suitable log files. The name of the files includes the current
866 date and rocket serial and flight numbers.
869 The radio frequency being monitored by the TeleDongle device is
870 displayed at the top of the window. You can configure the
871 frequency by clicking on the frequency box and selecting the desired
872 frequency. AltosUI remembers the last frequency selected for each
873 TeleDongle and selects that automatically the next time you use
877 Below the TeleDongle frequency selector, the window contains a few
878 significant pieces of information about the altimeter providing
879 the telemetry data stream:
883 <para>The configured call-sign</para>
886 <para>The device serial number</para>
889 <para>The flight number. Each altimeter remembers how many
895 The rocket flight state. Each flight passes through several
896 states including Pad, Boost, Fast, Coast, Drogue, Main and
902 The Received Signal Strength Indicator value. This lets
903 you know how strong a signal TeleDongle is receiving. The
904 radio inside TeleDongle operates down to about -99dBm;
905 weaker signals may not be receivable. The packet link uses
906 error detection and correction techniques which prevent
907 incorrect data from being reported.
912 The age of the displayed data, in seconds since the last
913 successfully received telemetry packet. In normal operation
914 this will stay in the low single digits. If the number starts
915 counting up, then you are no longer receiving data over the radio
916 link from the flight computer.
921 Finally, the largest portion of the window contains a set of
922 tabs, each of which contain some information about the rocket.
923 They're arranged in 'flight order' so that as the flight
924 progresses, the selected tab automatically switches to display
925 data relevant to the current state of the flight. You can select
926 other tabs at any time. The final 'table' tab displays all of
927 the raw telemetry values in one place in a spreadsheet-like format.
930 <title>Launch Pad</title>
932 The 'Launch Pad' tab shows information used to decide when the
933 rocket is ready for flight. The first elements include red/green
934 indicators, if any of these is red, you'll want to evaluate
935 whether the rocket is ready to launch:
939 Battery Voltage. This indicates whether the Li-Po battery
940 powering the TeleMetrum has sufficient charge to last for
941 the duration of the flight. A value of more than
942 3.7V is required for a 'GO' status.
947 Apogee Igniter Voltage. This indicates whether the apogee
948 igniter has continuity. If the igniter has a low
949 resistance, then the voltage measured here will be close
950 to the Li-Po battery voltage. A value greater than 3.2V is
951 required for a 'GO' status.
956 Main Igniter Voltage. This indicates whether the main
957 igniter has continuity. If the igniter has a low
958 resistance, then the voltage measured here will be close
959 to the Li-Po battery voltage. A value greater than 3.2V is
960 required for a 'GO' status.
965 On-board Data Logging. This indicates whether there is
966 space remaining on-board to store flight data for the
967 upcoming flight. If you've downloaded data, but failed
968 to erase flights, there may not be any space
969 left. TeleMetrum can store multiple flights, depending
970 on the configured maximum flight log size. TeleMini
971 stores only a single flight, so it will need to be
972 downloaded and erased after each flight to capture
973 data. This only affects on-board flight logging; the
974 altimeter will still transmit telemetry and fire
975 ejection charges at the proper times.
980 GPS Locked. For a TeleMetrum device, this indicates whether the GPS receiver is
981 currently able to compute position information. GPS requires
982 at least 4 satellites to compute an accurate position.
987 GPS Ready. For a TeleMetrum device, this indicates whether GPS has reported at least
988 10 consecutive positions without losing lock. This ensures
989 that the GPS receiver has reliable reception from the
995 The Launchpad tab also shows the computed launch pad position
996 and altitude, averaging many reported positions to improve the
1002 <title>Ascent</title>
1004 This tab is shown during Boost, Fast and Coast
1005 phases. The information displayed here helps monitor the
1006 rocket as it heads towards apogee.
1009 The height, speed and acceleration are shown along with the
1010 maximum values for each of them. This allows you to quickly
1011 answer the most commonly asked questions you'll hear during
1015 The current latitude and longitude reported by the TeleMetrum GPS are
1016 also shown. Note that under high acceleration, these values
1017 may not get updated as the GPS receiver loses position
1018 fix. Once the rocket starts coasting, the receiver should
1019 start reporting position again.
1022 Finally, the current igniter voltages are reported as in the
1023 Launch Pad tab. This can help diagnose deployment failures
1024 caused by wiring which comes loose under high acceleration.
1028 <title>Descent</title>
1030 Once the rocket has reached apogee and (we hope) activated the
1031 apogee charge, attention switches to tracking the rocket on
1032 the way back to the ground, and for dual-deploy flights,
1033 waiting for the main charge to fire.
1036 To monitor whether the apogee charge operated correctly, the
1037 current descent rate is reported along with the current
1038 height. Good descent rates vary based on the choice of recovery
1039 components, but generally range from 15-30m/s on drogue and should
1040 be below 10m/s when under the main parachute in a dual-deploy flight.
1043 For TeleMetrum altimeters, you can locate the rocket in the
1044 sky using the elevation and bearing information to figure
1045 out where to look. Elevation is in degrees above the
1046 horizon. Bearing is reported in degrees relative to true
1047 north. Range can help figure out how big the rocket will
1048 appear. Ground Distance shows how far it is to a point
1049 directly under the rocket and can help figure out where the
1050 rocket is likely to land. Note that all of these values are
1051 relative to the pad location. If the elevation is near 90°,
1052 the rocket is over the pad, not over you.
1055 Finally, the igniter voltages are reported in this tab as
1056 well, both to monitor the main charge as well as to see what
1057 the status of the apogee charge is. Note that some commercial
1058 e-matches are designed to retain continuity even after being
1059 fired, and will continue to show as green or return from red to
1064 <title>Landed</title>
1066 Once the rocket is on the ground, attention switches to
1067 recovery. While the radio signal is often lost once the
1068 rocket is on the ground, the last reported GPS position is
1069 generally within a short distance of the actual landing location.
1072 The last reported GPS position is reported both by
1073 latitude and longitude as well as a bearing and distance from
1074 the launch pad. The distance should give you a good idea of
1075 whether to walk or hitch a ride. Take the reported
1076 latitude and longitude and enter them into your hand-held GPS
1077 unit and have that compute a track to the landing location.
1080 Both TeleMini and TeleMetrum will continue to transmit RDF
1081 tones after landing, allowing you to locate the rocket by
1082 following the radio signal if necessary. You may need to get
1083 away from the clutter of the flight line, or even get up on
1084 a hill (or your neighbor's RV roof) to receive the RDF signal.
1087 The maximum height, speed and acceleration reported
1088 during the flight are displayed for your admiring observers.
1089 The accuracy of these immediate values depends on the quality
1090 of your radio link and how many packets were received.
1091 Recovering the on-board data after flight will likely yield
1092 more precise results.
1095 To get more detailed information about the flight, you can
1096 click on the 'Graph Flight' button which will bring up a
1097 graph window for the current flight.
1101 <title>Site Map</title>
1103 When the TeleMetrum has a GPS fix, the Site Map tab will map
1104 the rocket's position to make it easier for you to locate the
1105 rocket, both while it is in the air, and when it has landed. The
1106 rocket's state is indicated by color: white for pad, red for
1107 boost, pink for fast, yellow for coast, light blue for drogue,
1108 dark blue for main, and black for landed.
1111 The map's scale is approximately 3m (10ft) per pixel. The map
1112 can be dragged using the left mouse button. The map will attempt
1113 to keep the rocket roughly centered while data is being received.
1116 Images are fetched automatically via the Google Maps Static API,
1117 and cached on disk for reuse. If map images cannot be downloaded,
1118 the rocket's path will be traced on a dark gray background
1122 You can pre-load images for your favorite launch sites
1123 before you leave home; check out the 'Preload Maps' section below.
1128 <title>Save Flight Data</title>
1130 The altimeter records flight data to its internal flash memory.
1131 TeleMetrum data is recorded at a much higher rate than the telemetry
1132 system can handle, and is not subject to radio drop-outs. As
1133 such, it provides a more complete and precise record of the
1134 flight. The 'Save Flight Data' button allows you to read the
1135 flash memory and write it to disk. As TeleMini has only a barometer, it
1136 records data at the same rate as the telemetry signal, but there will be
1137 no data lost due to telemetry drop-outs.
1140 Clicking on the 'Save Flight Data' button brings up a list of
1141 connected TeleMetrum and TeleDongle devices. If you select a
1142 TeleMetrum device, the flight data will be downloaded from that
1143 device directly. If you select a TeleDongle device, flight data
1144 will be downloaded from an altimeter over radio link via the
1145 specified TeleDongle. See the chapter on Controlling An Altimeter
1146 Over The Radio Link for more information.
1149 After the device has been selected, a dialog showing the
1150 flight data saved in the device will be shown allowing you to
1151 select which flights to download and which to delete. With
1152 version 0.9 or newer firmware, you must erase flights in order
1153 for the space they consume to be reused by another
1154 flight. This prevents accidentally losing flight data
1155 if you neglect to download data before flying again. Note that
1156 if there is no more space available in the device, then no
1157 data will be recorded during the next flight.
1160 The file name for each flight log is computed automatically
1161 from the recorded flight date, altimeter serial number and
1162 flight number information.
1166 <title>Replay Flight</title>
1168 Select this button and you are prompted to select a flight
1169 record file, either a .telem file recording telemetry data or a
1170 .eeprom file containing flight data saved from the altimeter
1174 Once a flight record is selected, the flight monitor interface
1175 is displayed and the flight is re-enacted in real time. Check
1176 the Monitor Flight chapter above to learn how this window operates.
1180 <title>Graph Data</title>
1182 Select this button and you are prompted to select a flight
1183 record file, either a .telem file recording telemetry data or a
1184 .eeprom file containing flight data saved from
1188 Once a flight record is selected, a window with four tabs is
1189 opened. The first tab contains a graph with acceleration
1190 (blue), velocity (green) and altitude (red) of the flight,
1191 measured in metric units. The apogee(yellow) and main(magenta)
1192 igniter voltages are also displayed; high voltages indicate
1193 continuity, low voltages indicate open circuits. The second
1194 tab lets you configure which data to show in the graph. The
1195 third contains some basic flight statistics while the fourth
1196 has a map with the ground track of the flight displayed.
1199 The graph can be zoomed into a particular area by clicking and
1200 dragging down and to the right. Once zoomed, the graph can be
1201 reset by clicking and dragging up and to the left. Holding down
1202 control and clicking and dragging allows the graph to be panned.
1203 The right mouse button causes a pop-up menu to be displayed, giving
1204 you the option save or print the plot.
1207 Note that telemetry files will generally produce poor graphs
1208 due to the lower sampling rate and missed telemetry packets.
1209 Use saved flight data in .eeprom files for graphing where possible.
1213 <title>Export Data</title>
1215 This tool takes the raw data files and makes them available for
1216 external analysis. When you select this button, you are prompted to
1218 data file (either .eeprom or .telem will do, remember that
1219 .eeprom files contain higher resolution and more continuous
1220 data). Next, a second dialog appears which is used to select
1221 where to write the resulting file. It has a selector to choose
1222 between CSV and KML file formats.
1225 <title>Comma Separated Value Format</title>
1227 This is a text file containing the data in a form suitable for
1228 import into a spreadsheet or other external data analysis
1229 tool. The first few lines of the file contain the version and
1230 configuration information from the altimeter, then
1231 there is a single header line which labels all of the
1232 fields. All of these lines start with a '#' character which
1233 many tools can be configured to skip over.
1236 The remaining lines of the file contain the data, with each
1237 field separated by a comma and at least one space. All of
1238 the sensor values are converted to standard units, with the
1239 barometric data reported in both pressure, altitude and
1240 height above pad units.
1244 <title>Keyhole Markup Language (for Google Earth)</title>
1246 This is the format used by Google Earth to provide an overlay
1247 within that application. With this, you can use Google Earth to
1248 see the whole flight path in 3D.
1253 <title>Configure Altimeter</title>
1255 Select this button and then select either a TeleMetrum or
1256 TeleDongle Device from the list provided. Selecting a TeleDongle
1257 device will use the radio link to configure a remote altimeter.
1260 The first few lines of the dialog provide information about the
1261 connected device, including the product name,
1262 software version and hardware serial number. Below that are the
1263 individual configuration entries.
1266 At the bottom of the dialog, there are four buttons:
1271 Save. This writes any changes to the
1272 configuration parameter block in flash memory. If you don't
1273 press this button, any changes you make will be lost.
1278 Reset. This resets the dialog to the most recently saved values,
1279 erasing any changes you have made.
1284 Reboot. This reboots the device. Use this to
1285 switch from idle to pad mode by rebooting once the rocket is
1286 oriented for flight, or to confirm changes you think you saved
1292 Close. This closes the dialog. Any unsaved changes will be
1298 The rest of the dialog contains the parameters to be configured.
1301 <title>Main Deploy Altitude</title>
1303 This sets the altitude (above the recorded pad altitude) at
1304 which the 'main' igniter will fire. The drop-down menu shows
1305 some common values, but you can edit the text directly and
1306 choose whatever you like. If the apogee charge fires below
1307 this altitude, then the main charge will fire two seconds
1308 after the apogee charge fires.
1312 <title>Apogee Delay</title>
1314 When flying redundant electronics, it's often important to
1315 ensure that multiple apogee charges don't fire at precisely
1316 the same time, as that can over pressurize the apogee deployment
1317 bay and cause a structural failure of the air-frame. The Apogee
1318 Delay parameter tells the flight computer to fire the apogee
1319 charge a certain number of seconds after apogee has been
1324 <title>Radio Frequency</title>
1326 This configures which of the configured frequencies to use for both
1327 telemetry and packet command mode. Note that if you set this
1328 value via packet command mode, you will have to reconfigure
1329 the TeleDongle frequency before you will be able to use packet
1334 <title>Radio Calibration</title>
1336 The radios in every Altus Metrum device are calibrated at the
1337 factory to ensure that they transmit and receive on the
1338 specified frequency. If you need to you can adjust the calibration
1339 by changing this value. Do not do this without understanding what
1340 the value means, read the appendix on calibration and/or the source
1341 code for more information. To change a TeleDongle's calibration,
1342 you must reprogram the unit completely.
1346 <title>Callsign</title>
1348 This sets the call sign included in each telemetry packet. Set this
1349 as needed to conform to your local radio regulations.
1353 <title>Maximum Flight Log Size</title>
1355 This sets the space (in kilobytes) allocated for each flight
1356 log. The available space will be divided into chunks of this
1357 size. A smaller value will allow more flights to be stored,
1358 a larger value will record data from longer flights.
1362 <title>Ignite Mode</title>
1364 TeleMetrum and TeleMini provide two igniter channels as they
1365 were originally designed as dual-deploy flight
1366 computers. This configuration parameter allows the two
1367 channels to be used in different configurations.
1372 Dual Deploy. This is the usual mode of operation; the
1373 'apogee' channel is fired at apogee and the 'main'
1374 channel at the height above ground specified by the
1375 'Main Deploy Altitude' during descent.
1380 Redundant Apogee. This fires both channels at
1381 apogee, the 'apogee' channel first followed after a two second
1382 delay by the 'main' channel.
1387 Redundant Main. This fires both channels at the
1388 height above ground specified by the Main Deploy
1389 Altitude setting during descent. The 'apogee'
1390 channel is fired first, followed after a two second
1391 delay by the 'main' channel.
1397 <title>Pad Orientation</title>
1399 Because it includes an accelerometer, TeleMetrum is
1400 sensitive to the orientation of the board. By default, it
1401 expects the antenna end to point forward. This parameter
1402 allows that default to be changed, permitting the board to
1403 be mounted with the antenna pointing aft instead.
1408 Antenna Up. In this mode, the antenna end of the
1409 TeleMetrum board must point forward, in line with the
1410 expected flight path.
1415 Antenna Down. In this mode, the antenna end of the
1416 TeleMetrum board must point aft, in line with the
1417 expected flight path.
1424 <title>Configure AltosUI</title>
1426 This button presents a dialog so that you can configure the AltosUI global settings.
1429 <title>Voice Settings</title>
1431 AltosUI provides voice announcements during flight so that you
1432 can keep your eyes on the sky and still get information about
1433 the current flight status. However, sometimes you don't want
1438 <para>Enable—turns all voice announcements on and off</para>
1442 Test Voice—Plays a short message allowing you to verify
1443 that the audio system is working and the volume settings
1450 <title>Log Directory</title>
1452 AltosUI logs all telemetry data and saves all TeleMetrum flash
1453 data to this directory. This directory is also used as the
1454 staring point when selecting data files for display or export.
1457 Click on the directory name to bring up a directory choosing
1458 dialog, select a new directory and click 'Select Directory' to
1459 change where AltosUI reads and writes data files.
1463 <title>Callsign</title>
1465 This value is transmitted in each command packet sent from
1466 TeleDongle and received from an altimeter. It is not used in
1467 telemetry mode, as the callsign configured in the altimeter board
1468 is included in all telemetry packets. Configure this
1469 with the AltosUI operators call sign as needed to comply with
1470 your local radio regulations.
1473 Note that to successfully command a flight computer over the radio
1474 (to configure the altimeter, monitor idle, or fire pyro charges),
1475 the callsign configured here must exactly match the callsign
1476 configured in the flight computer. This matching is case
1481 <title>Imperial Units</title>
1483 This switches between metric units (meters) and imperial
1484 units (feet and miles). This affects the display of values
1485 use during flight monitoring, data graphing and all of the
1486 voice announcements. It does not change the units used when
1487 exporting to CSV files, those are always produced in metric units.
1491 <title>Font Size</title>
1493 Selects the set of fonts used in the flight monitor
1494 window. Choose between the small, medium and large sets.
1498 <title>Serial Debug</title>
1500 This causes all communication with a connected device to be
1501 dumped to the console from which AltosUI was started. If
1502 you've started it from an icon or menu entry, the output
1503 will simply be discarded. This mode can be useful to debug
1504 various serial communication issues.
1508 <title>Manage Frequencies</title>
1510 This brings up a dialog where you can configure the set of
1511 frequencies shown in the various frequency menus. You can
1512 add as many as you like, or even reconfigure the default
1513 set. Changing this list does not affect the frequency
1514 settings of any devices, it only changes the set of
1515 frequencies shown in the menus.
1520 <title>Configure Groundstation</title>
1522 Select this button and then select a TeleDongle Device from the list provided.
1525 The first few lines of the dialog provide information about the
1526 connected device, including the product name,
1527 software version and hardware serial number. Below that are the
1528 individual configuration entries.
1531 Note that the TeleDongle itself doesn't save any configuration
1532 data, the settings here are recorded on the local machine in
1533 the Java preferences database. Moving the TeleDongle to
1534 another machine, or using a different user account on the same
1535 machine will cause settings made here to have no effect.
1538 At the bottom of the dialog, there are three buttons:
1543 Save. This writes any changes to the
1544 local Java preferences file. If you don't
1545 press this button, any changes you make will be lost.
1550 Reset. This resets the dialog to the most recently saved values,
1551 erasing any changes you have made.
1556 Close. This closes the dialog. Any unsaved changes will be
1562 The rest of the dialog contains the parameters to be configured.
1565 <title>Frequency</title>
1567 This configures the frequency to use for both telemetry and
1568 packet command mode. Set this before starting any operation
1569 involving packet command mode so that it will use the right
1570 frequency. Telemetry monitoring mode also provides a menu to
1571 change the frequency, and that menu also sets the same Java
1572 preference value used here.
1576 <title>Radio Calibration</title>
1578 The radios in every Altus Metrum device are calibrated at the
1579 factory to ensure that they transmit and receive on the
1580 specified frequency. To change a TeleDongle's calibration,
1581 you must reprogram the unit completely, so this entry simply
1582 shows the current value and doesn't allow any changes.
1587 <title>Flash Image</title>
1589 This reprograms any Altus Metrum device by using a TeleMetrum
1590 or TeleDongle as a programming dongle. Please read the
1591 directions for flashing devices in the Updating Device
1592 Firmware chapter below.
1595 Once you have the programmer and target devices connected,
1596 push the 'Flash Image' button. That will present a dialog box
1597 listing all of the connected devices. Carefully select the
1598 programmer device, not the device to be programmed.
1601 Next, select the image to flash to the device. These are named
1602 with the product name and firmware version. The file selector
1603 will start in the directory containing the firmware included
1604 with the AltosUI package. Navigate to the directory containing
1605 the desired firmware if it isn't there.
1608 Next, a small dialog containing the device serial number and
1609 RF calibration values should appear. If these values are
1610 incorrect (possibly due to a corrupted image in the device),
1611 enter the correct values here.
1614 Finally, a dialog containing a progress bar will follow the
1615 programming process.
1618 When programming is complete, the target device will
1619 reboot. Note that if the target device is connected via USB, you
1620 will have to unplug it and then plug it back in for the USB
1621 connection to reset so that you can communicate with the device
1626 <title>Fire Igniter</title>
1628 This activates the igniter circuits in TeleMetrum to help test
1629 recovery systems deployment. Because this command can operate
1630 over the Packet Command Link, you can prepare the rocket as
1631 for flight and then test the recovery system without needing
1632 to snake wires inside the air-frame.
1635 Selecting the 'Fire Igniter' button brings up the usual device
1636 selection dialog. Pick the desired TeleDongle or TeleMetrum
1637 device. This brings up another window which shows the current
1638 continuity test status for both apogee and main charges.
1641 Next, select the desired igniter to fire. This will enable the
1645 Select the 'Arm' button. This enables the 'Fire' button. The
1646 word 'Arm' is replaced by a countdown timer indicating that
1647 you have 10 seconds to press the 'Fire' button or the system
1648 will deactivate, at which point you start over again at
1649 selecting the desired igniter.
1653 <title>Scan Channels</title>
1655 This listens for telemetry packets on all of the configured
1656 frequencies, displaying information about each device it
1657 receives a packet from. You can select which of the three
1658 telemetry formats should be tried; by default, it only listens
1659 for the standard telemetry packets used in v1.0 and later
1664 <title>Load Maps</title>
1666 Before heading out to a new launch site, you can use this to
1667 load satellite images in case you don't have internet
1668 connectivity at the site. This loads a fairly large area
1669 around the launch site, which should cover any flight you're likely to make.
1672 There's a drop-down menu of launch sites we know about; if
1673 your favorites aren't there, please let us know the lat/lon
1674 and name of the site. The contents of this list are actually
1675 downloaded at run-time, so as new sites are sent in, they'll
1676 get automatically added to this list.
1679 If the launch site isn't in the list, you can manually enter the lat/lon values
1682 Clicking the 'Load Map' button will fetch images from Google
1683 Maps; note that Google limits how many images you can fetch at
1684 once, so if you load more than one launch site, you may get
1685 some gray areas in the map which indicate that Google is tired
1686 of sending data to you. Try again later.
1690 <title>Monitor Idle</title>
1692 This brings up a dialog similar to the Monitor Flight UI,
1693 except it works with the altimeter in "idle" mode by sending
1694 query commands to discover the current state rather than
1695 listening for telemetry packets.
1700 <title>AltosDroid</title>
1702 AltosDroid provides the same flight monitoring capabilities as
1703 AltosUI, but runs on Android devices and is designed to connect
1704 to a TeleBT receiver over Bluetooth™. Altos Droid monitors
1705 telemetry data, logging it to internal storage in the Android
1706 device, and presents that data in a UI the same way the 'Monitor
1707 Flight' window does in AltosUI.
1710 This manual will explain how to configure AltosDroid, connect
1711 to TeleBT, operate the flight monitoring interface and describe
1712 what the displayed data means.
1715 <title>Installing AltosDroid</title>
1717 AltosDroid is included in the Google Play store. To install
1718 it on your Android device, open open the Google Play Store
1719 application and search for "altosdroid". Make sure you don't
1720 have a space between "altos" and "droid" or you probably won't
1721 find what you want. That should bring you to the right page
1722 from which you can download and install the application.
1726 <title>Connecting to TeleBT</title>
1728 Press the Android 'Menu' button or soft-key to see the
1729 configuration options available. Select the 'Connect a device'
1730 option and then the 'Scan for devices' entry at the bottom to
1731 look for your TeleBT device. Select your device, and when it
1732 asks for the code, enter '1234'.
1735 Subsequent connections will not require you to enter that
1736 code, and your 'paired' device will appear in the list without
1741 <title>Configuring AltosDroid</title>
1743 The only configuration option available for AltosDroid is
1744 which frequency to listen on. Press the Android 'Menu' button
1745 or soft-key and pick the 'Select radio frequency' entry. That
1746 brings up a menu of pre-set radio frequencies; pick the one
1747 which matches your altimeter.
1751 <title>Altos Droid Flight Monitoring</title>
1753 Altos Droid is designed to mimic the AltosUI flight monitoring
1754 display, providing separate tabs for each stage of your rocket
1755 flight along with a tab containing a map of the local area
1756 with icons marking the current location of the altimeter and
1762 The 'Launch Pad' tab shows information used to decide when the
1763 rocket is ready for flight. The first elements include red/green
1764 indicators, if any of these is red, you'll want to evaluate
1765 whether the rocket is ready to launch:
1769 Battery Voltage. This indicates whether the Li-Po battery
1770 powering the TeleMetrum has sufficient charge to last for
1771 the duration of the flight. A value of more than
1772 3.7V is required for a 'GO' status.
1777 Apogee Igniter Voltage. This indicates whether the apogee
1778 igniter has continuity. If the igniter has a low
1779 resistance, then the voltage measured here will be close
1780 to the Li-Po battery voltage. A value greater than 3.2V is
1781 required for a 'GO' status.
1786 Main Igniter Voltage. This indicates whether the main
1787 igniter has continuity. If the igniter has a low
1788 resistance, then the voltage measured here will be close
1789 to the Li-Po battery voltage. A value greater than 3.2V is
1790 required for a 'GO' status.
1795 On-board Data Logging. This indicates whether there is
1796 space remaining on-board to store flight data for the
1797 upcoming flight. If you've downloaded data, but failed
1798 to erase flights, there may not be any space
1799 left. TeleMetrum can store multiple flights, depending
1800 on the configured maximum flight log size. TeleMini
1801 stores only a single flight, so it will need to be
1802 downloaded and erased after each flight to capture
1803 data. This only affects on-board flight logging; the
1804 altimeter will still transmit telemetry and fire
1805 ejection charges at the proper times.
1810 GPS Locked. For a TeleMetrum device, this indicates whether the GPS receiver is
1811 currently able to compute position information. GPS requires
1812 at least 4 satellites to compute an accurate position.
1817 GPS Ready. For a TeleMetrum device, this indicates whether GPS has reported at least
1818 10 consecutive positions without losing lock. This ensures
1819 that the GPS receiver has reliable reception from the
1825 The Launchpad tab also shows the computed launch pad position
1826 and altitude, averaging many reported positions to improve the
1827 accuracy of the fix.
1833 <title>Downloading Flight Logs</title>
1835 Altos Droid always saves every bit of telemetry data it
1836 receives. To download that to a computer for use with AltosUI,
1837 simply remove the SD card from your Android device, or connect
1838 your device to your computer's USB port and browse the files
1839 on that device. You will find '.telem' files in the TeleMetrum
1840 directory that will work with AltosUI directly.
1845 <title>Using Altus Metrum Products</title>
1847 <title>Being Legal</title>
1849 First off, in the US, you need an <ulink url="http://www.altusmetrum.org/Radio/">amateur radio license</ulink> or
1850 other authorization to legally operate the radio transmitters that are part
1855 <title>In the Rocket</title>
1857 In the rocket itself, you just need a <ulink url="http://www.altusmetrum.org/TeleMetrum/">TeleMetrum</ulink> or
1858 <ulink url="http://www.altusmetrum.org/TeleMini/">TeleMini</ulink> board and
1859 a single-cell, 3.7 volt nominal Li-Po rechargeable battery. An
1860 850mAh battery weighs less than a 9V alkaline battery, and will
1861 run a TeleMetrum for hours.
1862 A 110mAh battery weighs less than a triple A battery and will run a TeleMetrum for
1863 a few hours, or a TeleMini for much (much) longer.
1866 By default, we ship the altimeters with a simple wire antenna. If your
1867 electronics bay or the air-frame it resides within is made of carbon fiber,
1868 which is opaque to RF signals, you may choose to have an SMA connector
1869 installed so that you can run a coaxial cable to an antenna mounted
1870 elsewhere in the rocket.
1874 <title>On the Ground</title>
1876 To receive the data stream from the rocket, you need an antenna and short
1877 feed-line connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. If possible, use an SMA to BNC
1878 adapter instead of feedline between the antenna feedpoint and
1879 TeleDongle, as this will give you the best performance. The
1880 TeleDongle in turn plugs directly into the USB port on a notebook
1881 computer. Because TeleDongle looks like a simple serial port, your computer
1882 does not require special device drivers... just plug it in.
1885 The GUI tool, AltosUI, is written in Java and runs across
1886 Linux, Mac OS and Windows. There's also a suite of C tools
1887 for Linux which can perform most of the same tasks.
1890 After the flight, you can use the radio link to extract the more detailed data
1891 logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
1892 TeleMetrum board directly. Pulling out the data without having to open up
1893 the rocket is pretty cool! A USB cable is also how you charge the Li-Po
1894 battery, so you'll want one of those anyway... the same cable used by lots
1895 of digital cameras and other modern electronic stuff will work fine.
1898 If your TeleMetrum-equipped rocket lands out of sight, you may enjoy having a hand-held GPS
1899 receiver, so that you can put in a way-point for the last reported rocket
1900 position before touch-down. This makes looking for your rocket a lot like
1901 Geo-Caching... just go to the way-point and look around starting from there.
1904 You may also enjoy having a ham radio "HT" that covers the 70cm band... you
1905 can use that with your antenna to direction-find the rocket on the ground
1906 the same way you can use a Walston or Beeline tracker. This can be handy
1907 if the rocket is hiding in sage brush or a tree, or if the last GPS position
1908 doesn't get you close enough because the rocket dropped into a canyon, or
1909 the wind is blowing it across a dry lake bed, or something like that... Keith
1910 and Bdale both currently own and use the Yaesu VX-7R at launches.
1913 So, to recap, on the ground the hardware you'll need includes:
1914 <orderedlist inheritnum='inherit' numeration='arabic'>
1916 an antenna and feed-line or adapter
1925 optionally, a hand-held GPS receiver
1928 optionally, an HT or receiver covering 435 MHz
1933 The best hand-held commercial directional antennas we've found for radio
1934 direction finding rockets are from
1935 <ulink url="http://www.arrowantennas.com/" >
1938 The 440-3 and 440-5 are both good choices for finding a
1939 TeleMetrum- or TeleMini- equipped rocket when used with a suitable
1940 70cm HT. TeleDongle and an SMA to BNC adapter fit perfectly
1941 between the driven element and reflector of Arrow antennas.
1945 <title>Data Analysis</title>
1947 Our software makes it easy to log the data from each flight, both the
1948 telemetry received during the flight itself, and the more
1949 complete data log recorded in the flash memory on the altimeter
1950 board. Once this data is on your computer, our post-flight tools make it
1951 easy to quickly get to the numbers everyone wants, like apogee altitude,
1952 max acceleration, and max velocity. You can also generate and view a
1953 standard set of plots showing the altitude, acceleration, and
1954 velocity of the rocket during flight. And you can even export a TeleMetrum data file
1955 usable with Google Maps and Google Earth for visualizing the flight path
1956 in two or three dimensions!
1959 Our ultimate goal is to emit a set of files for each flight that can be
1960 published as a web page per flight, or just viewed on your local disk with
1965 <title>Future Plans</title>
1967 In the future, we intend to offer "companion boards" for the rocket
1968 that will plug in to TeleMetrum to collect additional data, provide
1969 more pyro channels, and so forth.
1972 Also under design is a new flight computer with more sensors, more
1973 pyro channels, and a more powerful radio system designed for use
1974 in multi-stage, complex, and extreme altitude projects.
1977 We are also working on alternatives to TeleDongle. One is a
1978 a stand-alone, hand-held ground terminal that will allow monitoring
1979 the rocket's status, collecting data during flight, and logging data
1980 after flight without the need for a notebook computer on the
1981 flight line. Particularly since it is so difficult to read most
1982 notebook screens in direct sunlight, we think this will be a great
1983 thing to have. We are also working on a TeleDongle variant with
1984 Bluetooth that will work with Android phones and tablets.
1987 Because all of our work is open, both the hardware designs and the
1988 software, if you have some great idea for an addition to the current
1989 Altus Metrum family, feel free to dive in and help! Or let us know
1990 what you'd like to see that we aren't already working on, and maybe
1991 we'll get excited about it too...
1995 <ulink url="http://altusmetrum.org/">web site</ulink> for more news
1996 and information as our family of products evolves!
2001 <title>Altimeter Installation Recommendations</title>
2003 Building high-power rockets that fly safely is hard enough. Mix
2004 in some sophisticated electronics and a bunch of radio energy
2005 and oftentimes you find few perfect solutions. This chapter
2006 contains some suggestions about how to install Altus Metrum
2007 products into the rocket air-frame, including how to safely and
2008 reliably mix a variety of electronics into the same air-frame.
2011 <title>Mounting the Altimeter</title>
2013 The first consideration is to ensure that the altimeter is
2014 securely fastened to the air-frame. For TeleMetrum, we use
2015 nylon standoffs and nylon screws; they're good to at least 50G
2016 and cannot cause any electrical issues on the board. For
2017 TeleMini, we usually cut small pieces of 1/16" balsa to fit
2018 under the screw holes, and then take 2x56 nylon screws and
2019 screw them through the TeleMini mounting holes, through the
2020 balsa and into the underlying material.
2022 <orderedlist inheritnum='inherit' numeration='arabic'>
2024 Make sure TeleMetrum is aligned precisely along the axis of
2025 acceleration so that the accelerometer can accurately
2026 capture data during the flight.
2029 Watch for any metal touching components on the
2030 board. Shorting out connections on the bottom of the board
2031 can cause the altimeter to fail during flight.
2036 <title>Dealing with the Antenna</title>
2038 The antenna supplied is just a piece of solid, insulated,
2039 wire. If it gets damaged or broken, it can be easily
2040 replaced. It should be kept straight and not cut; bending or
2041 cutting it will change the resonant frequency and/or
2042 impedance, making it a less efficient radiator and thus
2043 reducing the range of the telemetry signal.
2046 Keeping metal away from the antenna will provide better range
2047 and a more even radiation pattern. In most rockets, it's not
2048 entirely possible to isolate the antenna from metal
2049 components; there are often bolts, all-thread and wires from other
2050 electronics to contend with. Just be aware that the more stuff
2051 like this around the antenna, the lower the range.
2054 Make sure the antenna is not inside a tube made or covered
2055 with conducting material. Carbon fiber is the most common
2056 culprit here -- CF is a good conductor and will effectively
2057 shield the antenna, dramatically reducing signal strength and
2058 range. Metallic flake paint is another effective shielding
2059 material which is to be avoided around any antennas.
2062 If the ebay is large enough, it can be convenient to simply
2063 mount the altimeter at one end and stretch the antenna out
2064 inside. Taping the antenna to the sled can keep it straight
2065 under acceleration. If there are metal rods, keep the
2066 antenna as far away as possible.
2069 For a shorter ebay, it's quite practical to have the antenna
2070 run through a bulkhead and into an adjacent bay. Drill a small
2071 hole in the bulkhead, pass the antenna wire through it and
2072 then seal it up with glue or clay. We've also used acrylic
2073 tubing to create a cavity for the antenna wire. This works a
2074 bit better in that the antenna is known to stay straight and
2075 not get folded by recovery components in the bay. Angle the
2076 tubing towards the side wall of the rocket and it ends up
2077 consuming very little space.
2080 If you need to place the antenna at a distance from the
2081 altimeter, you can replace the antenna with an edge-mounted
2082 SMA connector, and then run 50Ω coax from the board to the
2083 antenna. Building a remote antenna is beyond the scope of this
2088 <title>Preserving GPS Reception</title>
2090 The GPS antenna and receiver in TeleMetrum are highly
2091 sensitive and normally have no trouble tracking enough
2092 satellites to provide accurate position information for
2093 recovering the rocket. However, there are many ways to
2094 attenuate the GPS signal.
2095 <orderedlist inheritnum='inherit' numeration='arabic'>
2097 Conductive tubing or coatings. Carbon fiber and metal
2098 tubing, or metallic paint will all dramatically attenuate the
2099 GPS signal. We've never heard of anyone successfully
2100 receiving GPS from inside these materials.
2103 Metal components near the GPS patch antenna. These will
2104 de-tune the patch antenna, changing the resonant frequency
2105 away from the L1 carrier and reduce the effectiveness of the
2106 antenna. You can place as much stuff as you like beneath the
2107 antenna as that's covered with a ground plane. But, keep
2108 wires and metal out from above the patch antenna.
2114 <title>Radio Frequency Interference</title>
2116 Any altimeter will generate RFI; the digital circuits use
2117 high-frequency clocks that spray radio interference across a
2118 wide band. Altus Metrum altimeters generate intentional radio
2119 signals as well, increasing the amount of RF energy around the board.
2122 Rocketry altimeters also use precise sensors measuring air
2123 pressure and acceleration. Tiny changes in voltage can cause
2124 these sensor readings to vary by a huge amount. When the
2125 sensors start mis-reporting data, the altimeter can either
2126 fire the igniters at the wrong time, or not fire them at all.
2129 Voltages are induced when radio frequency energy is
2130 transmitted from one circuit to another. Here are things that
2131 influence the induced voltage and current:
2135 Keep wires from different circuits apart. Moving circuits
2136 further apart will reduce RFI.
2139 Avoid parallel wires from different circuits. The longer two
2140 wires run parallel to one another, the larger the amount of
2141 transferred energy. Cross wires at right angles to reduce
2145 Twist wires from the same circuits. Two wires the same
2146 distance from the transmitter will get the same amount of
2147 induced energy which will then cancel out. Any time you have
2148 a wire pair running together, twist the pair together to
2149 even out distances and reduce RFI. For altimeters, this
2150 includes battery leads, switch hookups and igniter
2154 Avoid resonant lengths. Know what frequencies are present
2155 in the environment and avoid having wire lengths near a
2156 natural resonant length. Altusmetrum products transmit on the
2157 70cm amateur band, so you should avoid lengths that are a
2158 simple ratio of that length; essentially any multiple of 1/4
2159 of the wavelength (17.5cm).
2164 <title>The Barometric Sensor</title>
2166 Altusmetrum altimeters measure altitude with a barometric
2167 sensor, essentially measuring the amount of air above the
2168 rocket to figure out how high it is. A large number of
2169 measurements are taken as the altimeter initializes itself to
2170 figure out the pad altitude. Subsequent measurements are then
2171 used to compute the height above the pad.
2174 To accurately measure atmospheric pressure, the ebay
2175 containing the altimeter must be vented outside the
2176 air-frame. The vent must be placed in a region of linear
2177 airflow, have smooth edges, and away from areas of increasing or
2178 decreasing pressure.
2181 The barometric sensor in the altimeter is quite sensitive to
2182 chemical damage from the products of APCP or BP combustion, so
2183 make sure the ebay is carefully sealed from any compartment
2184 which contains ejection charges or motors.
2188 <title>Ground Testing</title>
2190 The most important aspect of any installation is careful
2191 ground testing. Bringing an air-frame up to the LCO table which
2192 hasn't been ground tested can lead to delays or ejection
2193 charges firing on the pad, or, even worse, a recovery system
2197 Do a 'full systems' test that includes wiring up all igniters
2198 without any BP and turning on all of the electronics in flight
2199 mode. This will catch any mistakes in wiring and any residual
2200 RFI issues that might accidentally fire igniters at the wrong
2201 time. Let the air-frame sit for several minutes, checking for
2202 adequate telemetry signal strength and GPS lock. If any igniters
2203 fire unexpectedly, find and resolve the issue before loading any
2207 Ground test the ejection charges. Prepare the rocket for
2208 flight, loading ejection charges and igniters. Completely
2209 assemble the air-frame and then use the 'Fire Igniters'
2210 interface through a TeleDongle to command each charge to
2211 fire. Make sure the charge is sufficient to robustly separate
2212 the air-frame and deploy the recovery system.
2217 <title>Updating Device Firmware</title>
2219 The big concept to understand is that you have to use a
2220 TeleDongle as a programmer to update a TeleMetrum or TeleMini,
2221 and a TeleMetrum or other TeleDongle to program the TeleDongle
2222 Due to limited memory resources in the cc1111, we don't support
2223 programming directly over USB.
2226 You may wish to begin by ensuring you have current firmware images.
2227 These are distributed as part of the AltOS software bundle that
2228 also includes the AltosUI ground station program. Newer ground
2229 station versions typically work fine with older firmware versions,
2230 so you don't need to update your devices just to try out new
2231 software features. You can always download the most recent
2232 version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
2235 We recommend updating the altimeter first, before updating TeleDongle.
2238 <title>Updating TeleMetrum Firmware</title>
2239 <orderedlist inheritnum='inherit' numeration='arabic'>
2241 Find the 'programming cable' that you got as part of the starter
2242 kit, that has a red 8-pin MicroMaTch connector on one end and a
2243 red 4-pin MicroMaTch connector on the other end.
2246 Take the 2 screws out of the TeleDongle case to get access
2247 to the circuit board.
2250 Plug the 8-pin end of the programming cable to the
2251 matching connector on the TeleDongle, and the 4-pin end to the
2252 matching connector on the TeleMetrum.
2253 Note that each MicroMaTch connector has an alignment pin that
2254 goes through a hole in the PC board when you have the cable
2258 Attach a battery to the TeleMetrum board.
2261 Plug the TeleDongle into your computer's USB port, and power
2265 Run AltosUI, and select 'Flash Image' from the File menu.
2268 Pick the TeleDongle device from the list, identifying it as the
2272 Select the image you want put on the TeleMetrum, which should have a
2273 name in the form telemetrum-v1.2-1.0.0.ihx. It should be visible
2274 in the default directory, if not you may have to poke around
2275 your system to find it.
2278 Make sure the configuration parameters are reasonable
2279 looking. If the serial number and/or RF configuration
2280 values aren't right, you'll need to change them.
2283 Hit the 'OK' button and the software should proceed to flash
2284 the TeleMetrum with new firmware, showing a progress bar.
2287 Confirm that the TeleMetrum board seems to have updated OK, which you
2288 can do by plugging in to it over USB and using a terminal program
2289 to connect to the board and issue the 'v' command to check
2293 If something goes wrong, give it another try.
2298 <title>Updating TeleMini Firmware</title>
2299 <orderedlist inheritnum='inherit' numeration='arabic'>
2301 You'll need a special 'programming cable' to reprogram the
2302 TeleMini. It's available on the Altus Metrum web store, or
2303 you can make your own using an 8-pin MicroMaTch connector on
2304 one end and a set of four pins on the other.
2307 Take the 2 screws out of the TeleDongle case to get access
2308 to the circuit board.
2311 Plug the 8-pin end of the programming cable to the matching
2312 connector on the TeleDongle, and the 4-pins into the holes
2313 in the TeleMini circuit board. Note that the MicroMaTch
2314 connector has an alignment pin that goes through a hole in
2315 the PC board when you have the cable oriented correctly, and
2316 that pin 1 on the TeleMini board is marked with a square pad
2317 while the other pins have round pads.
2320 Attach a battery to the TeleMini board.
2323 Plug the TeleDongle into your computer's USB port, and power
2327 Run AltosUI, and select 'Flash Image' from the File menu.
2330 Pick the TeleDongle device from the list, identifying it as the
2334 Select the image you want put on the TeleMini, which should have a
2335 name in the form telemini-v1.0-1.0.0.ihx. It should be visible
2336 in the default directory, if not you may have to poke around
2337 your system to find it.
2340 Make sure the configuration parameters are reasonable
2341 looking. If the serial number and/or RF configuration
2342 values aren't right, you'll need to change them.
2345 Hit the 'OK' button and the software should proceed to flash
2346 the TeleMini with new firmware, showing a progress bar.
2349 Confirm that the TeleMini board seems to have updated OK, which you
2350 can do by configuring it over the radio link through the TeleDongle, or
2351 letting it come up in "flight" mode and listening for telemetry.
2354 If something goes wrong, give it another try.
2359 <title>Updating TeleDongle Firmware</title>
2361 Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
2362 firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
2364 <orderedlist inheritnum='inherit' numeration='arabic'>
2366 Find the 'programming cable' that you got as part of the starter
2367 kit, that has a red 8-pin MicroMaTch connector on one end and a
2368 red 4-pin MicroMaTch connector on the other end.
2371 Find the USB cable that you got as part of the starter kit, and
2372 plug the "mini" end in to the mating connector on TeleMetrum or TeleDongle.
2375 Take the 2 screws out of the TeleDongle case to get access
2376 to the circuit board.
2379 Plug the 8-pin end of the programming cable to the
2380 matching connector on the programmer, and the 4-pin end to the
2381 matching connector on the TeleDongle.
2382 Note that each MicroMaTch connector has an alignment pin that
2383 goes through a hole in the PC board when you have the cable
2387 Attach a battery to the TeleMetrum board if you're using one.
2390 Plug both the programmer and the TeleDongle into your computer's USB
2391 ports, and power up the programmer.
2394 Run AltosUI, and select 'Flash Image' from the File menu.
2397 Pick the programmer device from the list, identifying it as the
2401 Select the image you want put on the TeleDongle, which should have a
2402 name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
2403 in the default directory, if not you may have to poke around
2404 your system to find it.
2407 Make sure the configuration parameters are reasonable
2408 looking. If the serial number and/or RF configuration
2409 values aren't right, you'll need to change them. The TeleDongle
2410 serial number is on the "bottom" of the circuit board, and can
2411 usually be read through the translucent blue plastic case without
2412 needing to remove the board from the case.
2415 Hit the 'OK' button and the software should proceed to flash
2416 the TeleDongle with new firmware, showing a progress bar.
2419 Confirm that the TeleDongle board seems to have updated OK, which you
2420 can do by plugging in to it over USB and using a terminal program
2421 to connect to the board and issue the 'v' command to check
2422 the version, etc. Once you're happy, remove the programming cable
2423 and put the cover back on the TeleDongle.
2426 If something goes wrong, give it another try.
2430 Be careful removing the programming cable from the locking 8-pin
2431 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
2432 screwdriver or knife blade to gently pry the locking ears out
2433 slightly to extract the connector. We used a locking connector on
2434 TeleMetrum to help ensure that the cabling to companion boards
2435 used in a rocket don't ever come loose accidentally in flight.
2440 <title>Hardware Specifications</title>
2442 <title>TeleMetrum Specifications</title>
2446 Recording altimeter for model rocketry.
2451 Supports dual deployment (can fire 2 ejection charges).
2456 70cm ham-band transceiver for telemetry down-link.
2461 Barometric pressure sensor good to 45k feet MSL.
2466 1-axis high-g accelerometer for motor characterization, capable of
2467 +/- 50g using default part.
2472 On-board, integrated GPS receiver with 5Hz update rate capability.
2477 On-board 1 megabyte non-volatile memory for flight data storage.
2482 USB interface for battery charging, configuration, and data recovery.
2487 Fully integrated support for Li-Po rechargeable batteries.
2492 Uses Li-Po to fire e-matches, can be modified to support
2493 optional separate pyro battery if needed.
2498 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
2504 <title>TeleMini Specifications</title>
2508 Recording altimeter for model rocketry.
2513 Supports dual deployment (can fire 2 ejection charges).
2518 70cm ham-band transceiver for telemetry down-link.
2523 Barometric pressure sensor good to 45k feet MSL.
2528 On-board 5 kilobyte non-volatile memory for flight data storage.
2533 RF interface for configuration, and data recovery.
2538 Support for Li-Po rechargeable batteries, using an external charger.
2543 Uses Li-Po to fire e-matches, can be modified to support
2544 optional separate pyro battery if needed.
2549 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube.
2558 TeleMetrum seems to shut off when disconnected from the
2559 computer. Make sure the battery is adequately charged. Remember the
2560 unit will pull more power than the USB port can deliver before the
2561 GPS enters "locked" mode. The battery charges best when TeleMetrum
2565 It's impossible to stop the TeleDongle when it's in "p" mode, I have
2566 to unplug the USB cable? Make sure you have tried to "escape out" of
2567 this mode. If this doesn't work the reboot procedure for the
2568 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
2569 outgoing buffer IF your "escape out" ('~~') does not work.
2570 At this point using either 'ao-view' (or possibly
2571 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
2575 The amber LED (on the TeleMetrum) lights up when both
2576 battery and USB are connected. Does this mean it's charging?
2577 Yes, the yellow LED indicates the charging at the 'regular' rate.
2578 If the led is out but the unit is still plugged into a USB port,
2579 then the battery is being charged at a 'trickle' rate.
2582 There are no "dit-dah-dah-dit" sound or lights like the manual mentions?
2583 That's the "pad" mode. Weak batteries might be the problem.
2584 It is also possible that the TeleMetrum is horizontal and the output
2585 is instead a "dit-dit" meaning 'idle'. For TeleMini, it's possible that
2586 it received a command packet which would have left it in "pad" mode.
2589 How do I save flight data?
2590 Live telemetry is written to file(s) whenever AltosUI is connected
2591 to the TeleDongle. The file area defaults to ~/TeleMetrum
2592 but is easily changed using the menus in AltosUI. The files that
2593 are written end in '.telem'. The after-flight
2594 data-dumped files will end in .eeprom and represent continuous data
2595 unlike the .telem files that are subject to losses
2596 along the RF data path.
2597 See the above instructions on what and how to save the eeprom stored
2598 data after physically retrieving your altimeter. Make sure to save
2599 the on-board data after each flight; while the TeleMetrum can store
2600 multiple flights, you never know when you'll lose the altimeter...
2604 <title>Notes for Older Software</title>
2607 Before AltosUI was written, using Altus Metrum devices required
2608 some finesse with the Linux command line. There was a limited
2609 GUI tool, ao-view, which provided functionality similar to the
2610 Monitor Flight window in AltosUI, but everything else was a
2611 fairly 80's experience. This appendix includes documentation for
2612 using that software.
2616 Both TeleMetrum and TeleDongle can be directly communicated
2617 with using USB ports. The first thing you should try after getting
2618 both units plugged into to your computer's USB port(s) is to run
2619 'ao-list' from a terminal-window to see what port-device-name each
2620 device has been assigned by the operating system.
2621 You will need this information to access the devices via their
2622 respective on-board firmware and data using other command line
2623 programs in the AltOS software suite.
2626 TeleMini can be communicated with through a TeleDongle device
2627 over the radio link. When first booted, TeleMini listens for a
2628 TeleDongle device and if it receives a packet, it goes into
2629 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be
2630 launched. The easiest way to get it talking is to start the
2631 communication link on the TeleDongle and the power up the
2635 To access the device's firmware for configuration you need a terminal
2636 program such as you would use to talk to a modem. The software
2637 authors prefer using the program 'cu' which comes from the UUCP package
2638 on most Unix-like systems such as Linux. An example command line for
2639 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
2640 indicated from running the
2641 ao-list program. Another reasonable terminal program for Linux is
2642 'cutecom'. The default 'escape'
2643 character used by CU (i.e. the character you use to
2644 issue commands to cu itself instead of sending the command as input
2645 to the connected device) is a '~'. You will need this for use in
2646 only two different ways during normal operations. First is to exit
2647 the program by sending a '~.' which is called a 'escape-disconnect'
2648 and allows you to close-out from 'cu'. The
2649 second use will be outlined later.
2652 All of the Altus Metrum devices share the concept of a two level
2653 command set in their firmware.
2654 The first layer has several single letter commands. Once
2655 you are using 'cu' (or 'cutecom') sending (typing) a '?'
2656 returns a full list of these
2657 commands. The second level are configuration sub-commands accessed
2658 using the 'c' command, for
2659 instance typing 'c?' will give you this second level of commands
2660 (all of which require the
2661 letter 'c' to access). Please note that most configuration options
2662 are stored only in Flash memory; TeleDongle doesn't provide any storage
2663 for these options and so they'll all be lost when you unplug it.
2666 Try setting these configuration ('c' or second level menu) values. A good
2667 place to start is by setting your call sign. By default, the boards
2668 use 'N0CALL' which is cute, but not exactly legal!
2669 Spend a few minutes getting comfortable with the units, their
2670 firmware, and 'cu' (or possibly 'cutecom').
2671 For instance, try to send
2672 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
2673 Verify you can connect and disconnect from the units while in your
2674 terminal program by sending the escape-disconnect mentioned above.
2677 To set the radio frequency, use the 'c R' command to specify the
2678 radio transceiver configuration parameter. This parameter is computed
2679 using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
2680 the standard calibration reference frequency, 'S', (normally 434.550MHz):
2684 Round the result to the nearest integer value.
2685 As with all 'c' sub-commands, follow this with a 'c w' to write the
2686 change to the parameter block in the on-board flash on
2687 your altimeter board if you want the change to stay in place across reboots.
2690 To set the apogee delay, use the 'c d' command.
2691 As with all 'c' sub-commands, follow this with a 'c w' to write the
2692 change to the parameter block in the on-board DataFlash chip.
2695 To set the main deployment altitude, use the 'c m' command.
2696 As with all 'c' sub-commands, follow this with a 'c w' to write the
2697 change to the parameter block in the on-board DataFlash chip.
2700 To calibrate the radio frequency, connect the UHF antenna port to a
2701 frequency counter, set the board to 434.550MHz, and use the 'C'
2702 command to generate a CW carrier. Wait for the transmitter temperature
2703 to stabilize and the frequency to settle down.
2704 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 the 'reboot' command, which is very useful on the altimeters,
2715 will likely just cause problems with the dongle. The *correct* way
2716 to reset the dongle is just to unplug and re-plug it.
2719 A fun thing to do at the launch site and something you can do while
2720 learning how to use these units is to play with the radio link access
2721 between an altimeter and the TeleDongle. Be aware that you *must* create
2722 some physical separation between the devices, otherwise the link will
2723 not function due to signal overload in the receivers in each device.
2726 Now might be a good time to take a break and read the rest of this
2727 manual, particularly about the two "modes" that the altimeters
2728 can be placed in. TeleMetrum uses the position of the device when booting
2729 up will determine whether the unit is in "pad" or "idle" mode. TeleMini
2730 enters "idle" mode when it receives a command packet within the first 5 seconds
2731 of being powered up, otherwise it enters "pad" mode.
2734 You can access an altimeter in idle mode from the TeleDongle's USB
2735 connection using the radio link
2736 by issuing a 'p' command to the TeleDongle. Practice connecting and
2737 disconnecting ('~~' while using 'cu') from the altimeter. If
2738 you cannot escape out of the "p" command, (by using a '~~' when in
2739 CU) then it is likely that your kernel has issues. Try a newer version.
2742 Using this radio link allows you to configure the altimeter, test
2743 fire e-matches and igniters from the flight line, check pyro-match
2744 continuity and so forth. You can leave the unit turned on while it
2745 is in 'idle mode' and then place the
2746 rocket vertically on the launch pad, walk away and then issue a
2747 reboot command. The altimeter will reboot and start sending data
2748 having changed to the "pad" mode. If the TeleDongle is not receiving
2749 this data, you can disconnect 'cu' from the TeleDongle using the
2750 procedures mentioned above and THEN connect to the TeleDongle from
2751 inside 'ao-view'. If this doesn't work, disconnect from the
2752 TeleDongle, unplug it, and try again after plugging it back in.
2755 In order to reduce the chance of accidental firing of pyrotechnic
2756 charges, the command to fire a charge is intentionally somewhat
2757 difficult to type, and the built-in help is slightly cryptic to
2758 prevent accidental echoing of characters from the help text back at
2759 the board from firing a charge. The command to fire the apogee
2760 drogue charge is 'i DoIt drogue' and the command to fire the main
2761 charge is 'i DoIt main'.
2764 On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
2765 and 'ao-view' will both auditorily announce and visually indicate
2767 Now you can launch knowing that you have a good data path and
2768 good satellite lock for flight data and recovery. Remember
2769 you MUST tell ao-view to connect to the TeleDongle explicitly in
2770 order for ao-view to be able to receive data.
2773 The altimeters provide RDF (radio direction finding) tones on
2774 the pad, during descent and after landing. These can be used to
2775 locate the rocket using a directional antenna; the signal
2776 strength providing an indication of the direction from receiver to rocket.
2779 TeleMetrum also provides GPS tracking data, which can further simplify
2780 locating the rocket once it has landed. (The last good GPS data
2781 received before touch-down will be on the data screen of 'ao-view'.)
2784 Once you have recovered the rocket you can download the eeprom
2785 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
2786 either a USB cable or over the radio link using TeleDongle.
2787 And by following the man page for 'ao-postflight' you can create
2788 various data output reports, graphs, and even KML data to see the
2789 flight trajectory in Google-earth. (Moving the viewing angle making
2790 sure to connect the yellow lines while in Google-earth is the proper
2794 As for ao-view.... some things are in the menu but don't do anything
2795 very useful. The developers have stopped working on ao-view to focus
2796 on a new, cross-platform ground station program. So ao-view may or
2797 may not be updated in the future. Mostly you just use
2798 the Log and Device menus. It has a wonderful display of the incoming
2799 flight data and I am sure you will enjoy what it has to say to you
2800 once you enable the voice output!
2804 <title>Drill Templates</title>
2806 These images, when printed, provide precise templates for the
2807 mounting holes in Altus Metrum flight computers
2810 <title>TeleMetrum template</title>
2812 TeleMetrum has overall dimensions of 1.000 x 2.750 inches, and the
2813 mounting holes are sized for use with 4-40 or M3 screws.
2815 <mediaobject id="TeleMetrumTemplate">
2817 <imagedata format="SVG" fileref="telemetrum.svg"/>
2822 <title>TeleMini template</title>
2824 TeleMini has overall dimensions of 0.500 x 1.500 inches, and the
2825 mounting holes are sized for use with 2-56 or M2 screws.
2827 <mediaobject id="TeleMiniTemplate">
2829 <imagedata format="SVG" fileref="telemini.svg"/>
2835 <title>Calibration</title>
2837 There are only two calibrations required for a TeleMetrum board, and
2838 only one for TeleDongle and TeleMini. All boards are shipped from
2839 the factory pre-calibrated, but the procedures are documented here
2840 in case they are ever needed. Re-calibration is not supported by
2841 AltosUI, you must connect to the board with a serial terminal program
2842 and interact directly with the on-board command interpreter to effect
2846 <title>Radio Frequency</title>
2848 The radio frequency is synthesized from a clock based on the 48 MHz
2849 crystal on the board. The actual frequency of this oscillator
2850 must be measured to generate a calibration constant. While our
2852 bandwidth is wide enough to allow boards to communicate even when
2853 their oscillators are not on exactly the same frequency, performance
2854 is best when they are closely matched.
2855 Radio frequency calibration requires a calibrated frequency counter.
2856 Fortunately, once set, the variation in frequency due to aging and
2857 temperature changes is small enough that re-calibration by customers
2858 should generally not be required.
2861 To calibrate the radio frequency, connect the UHF antenna port to a
2862 frequency counter, set the board to 434.550MHz, and use the 'C'
2863 command in the on-board command interpreter to generate a CW
2864 carrier. For TeleMetrum, this is best done over USB. For TeleMini,
2865 note that the only way to escape the 'C' command is via power cycle
2866 since the board will no longer be listening for commands once it
2867 starts generating a CW carrier.
2870 Wait for the transmitter temperature to stabilize and the frequency
2871 to settle down. Then, divide 434.550 MHz by the
2872 measured frequency and multiply by the current radio cal value show
2873 in the 'c s' command. For an unprogrammed board, the default value
2874 is 1186611. Take the resulting integer and program it using the 'c f'
2875 command. Testing with the 'C' command again should show a carrier
2876 within a few tens of Hertz of the intended frequency.
2877 As with all 'c' sub-commands, follow this with a 'c w' to write the
2878 change to the parameter block in the on-board DataFlash chip.
2881 Note that any time you re-do the radio frequency calibration, the
2882 radio frequency is reset to the default 434.550 Mhz. If you want
2883 to use another frequency, you will have to set that again after
2884 calibration is completed.
2888 <title>TeleMetrum Accelerometer</title>
2890 The TeleMetrum accelerometer we use has its own 5 volt power
2892 the output must be passed through a resistive voltage divider to match
2893 the input of our 3.3 volt ADC. This means that unlike the barometric
2894 sensor, the output of the acceleration sensor is not ratio-metric to
2895 the ADC converter, and calibration is required. Explicitly
2896 calibrating the accelerometers also allows us to load any device
2897 from a Freescale family that includes at least +/- 40g, 50g, 100g,
2898 and 200g parts. Using gravity,
2899 a simple 2-point calibration yields acceptable results capturing both
2900 the different sensitivities and ranges of the different accelerometer
2901 parts and any variation in power supply voltages or resistor values
2902 in the divider network.
2905 To calibrate the acceleration sensor, use the 'c a 0' command. You
2906 will be prompted to orient the board vertically with the UHF antenna
2907 up and press a key, then to orient the board vertically with the
2908 UHF antenna down and press a key. Note that the accuracy of this
2909 calibration depends primarily on how perfectly vertical and still
2910 the board is held during the cal process. As with all 'c'
2911 sub-commands, follow this with a 'c w' to write the
2912 change to the parameter block in the on-board DataFlash chip.
2915 The +1g and -1g calibration points are included in each telemetry
2916 frame and are part of the header stored in onboard flash to be
2917 downloaded after flight. We always store and return raw ADC
2918 samples for each sensor... so nothing is permanently "lost" or
2919 "damaged" if the calibration is poor.
2922 In the unlikely event an accel cal goes badly, it is possible
2923 that TeleMetrum may always come up in 'pad mode' and as such not be
2924 listening to either the USB or radio link. If that happens,
2925 there is a special hook in the firmware to force the board back
2926 in to 'idle mode' so you can re-do the cal. To use this hook, you
2927 just need to ground the SPI clock pin at power-on. This pin is
2928 available as pin 2 on the 8-pin companion connector, and pin 1 is
2929 ground. So either carefully install a fine-gauge wire jumper
2930 between the two pins closest to the index hole end of the 8-pin
2931 connector, or plug in the programming cable to the 8-pin connector
2932 and use a small screwdriver or similar to short the two pins closest
2933 to the index post on the 4-pin end of the programming cable, and
2934 power up the board. It should come up in 'idle mode' (two beeps),
2940 xmlns:xi="http://www.w3.org/2001/XInclude">
2941 <title>Release Notes</title>
2942 <simplesect><title>Version 1.3</title><xi:include href="release-notes-1.3.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2943 <simplesect><title>Version 1.2.1</title><xi:include href="release-notes-1.2.1.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2944 <simplesect><title>Version 1.2</title><xi:include href="release-notes-1.2.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2945 <simplesect><title>Version 1.1.1</title><xi:include href="release-notes-1.1.1.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2946 <simplesect><title>Version 1.1</title><xi:include href="release-notes-1.1.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2947 <simplesect><title>Version 1.0.1</title><xi:include href="release-notes-1.0.1.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2948 <simplesect><title>Version 0.9.2</title><xi:include href="release-notes-0.9.2.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2949 <simplesect><title>Version 0.9</title><xi:include href="release-notes-0.9.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2950 <simplesect><title>Version 0.8</title><xi:include href="release-notes-0.8.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2951 <simplesect><title>Version 0.7.1</title><xi:include href="release-notes-0.7.1.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2955 <!-- LocalWords: Altusmetrum
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