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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>
107 <title>Acknowledgements</title>
109 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing "The
110 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
111 Kit" which formed the basis of the original Getting Started chapter
112 in this manual. Bob was one of our first customers for a production
113 TeleMetrum, and his continued enthusiasm and contributions
114 are immensely gratifying and highly appreciated!
117 And thanks to Anthony (AJ) Towns for major contributions including
118 the AltosUI graphing and site map code and associated documentation.
119 Free software means that our customers and friends can become our
120 collaborators, and we certainly appreciate this level of
124 Have fun using these products, and we hope to meet all of you
125 out on the rocket flight line somewhere.
128 NAR #87103, TRA #12201
130 Keith Packard, KD7SQG
131 NAR #88757, TRA #12200
136 <title>Introduction and Overview</title>
138 Welcome to the Altus Metrum community! Our circuits and software reflect
139 our passion for both hobby rocketry and Free Software. We hope their
140 capabilities and performance will delight you in every way, but by
141 releasing all of our hardware and software designs under open licenses,
142 we also hope to empower you to take as active a role in our collective
146 The first device created for our community was TeleMetrum, a dual
147 deploy altimeter with fully integrated GPS and radio telemetry
148 as standard features, and a "companion interface" that will
149 support optional capabilities in the future. The latest version
150 of TeleMetrum, v2.0, has all of the same features but with
151 improved sensors and radio to offer increased performance.
154 Our second device was TeleMini, a dual deploy altimeter with
155 radio telemetry and radio direction finding. The first version
156 of this device was only 13mm by 38mm (½ inch by 1½ inches) and
157 could fit easily in an 18mm air-frame. The latest version, v2.0,
158 includes a beeper, USB data download and extended on-board
159 flight logging, along with an improved barometric sensor.
162 TeleMega is our most sophisticated device, including six pyro
163 channels (four of which are fully programmable), integrated GPS,
164 integrated gyroscopes for staging/air-start inhibit and high
165 performance telemetry.
168 EasyMini is a dual-deploy altimeter with logging and built-in
172 TeleDongle was our first ground station, providing a USB to RF
173 interfaces for communicating with the altimeters. Combined with
174 your choice of antenna and notebook computer, TeleDongle and our
175 associated user interface software form a complete ground
176 station capable of logging and displaying in-flight telemetry,
177 aiding rocket recovery, then processing and archiving flight
178 data for analysis and review.
181 For a slightly more portable ground station experience that also
182 provides direct rocket recovery support, TeleBT offers flight
183 monitoring and data logging using a Bluetooth connection between
184 the receiver and an Android device that has the Altos Droid
185 application installed from the Google Play store.
188 More products will be added to the Altus Metrum family over time, and
189 we currently envision that this will be a single, comprehensive manual
190 for the entire product family.
194 <title>Getting Started</title>
196 The first thing to do after you check the inventory of parts in your
197 "starter kit" is to charge the battery.
200 For TeleMetrum and TeleMega, the battery can be charged by plugging it into the
201 corresponding socket of the device and then using the USB
202 cable to plug the flight computer into your computer's USB socket. The
203 on-board circuitry will charge the battery whenever it is plugged
204 in, because the on-off switch does NOT control the
208 On TeleMetrum v1 boards, when the GPS chip is initially
209 searching for satellites, TeleMetrum will consume more current
210 than it can pull from the USB port, so the battery must be
211 attached in order to get satellite lock. Once GPS is locked,
212 the current consumption goes back down enough to enable charging
213 while running. So it's a good idea to fully charge the battery
214 as your first item of business so there is no issue getting and
215 maintaining satellite lock. The yellow charge indicator led
216 will go out when the battery is nearly full and the charger goes
217 to trickle charge. It can take several hours to fully recharge a
218 deeply discharged battery.
221 TeleMetrum v2.0 and TeleMega use a higher power battery charger,
222 allowing them to charge the battery while running the board at
223 maximum power. When the battery is charging, or when the board
224 is consuming a lot of power, the red LED will be lit. When the
225 battery is fully charged, the green LED will be lit. When the
226 battery is damaged or missing, both LEDs will be lit, which
230 The Lithium Polymer TeleMini and EasyMini battery can be charged by
231 disconnecting it from the board and plugging it into a
232 standalone battery charger such as the LipoCharger product
233 included in TeleMini Starter Kits, and connecting that via a USB
234 cable to a laptop or other USB power source.
237 You can also choose to use another battery with TeleMini v2.0
238 and EasyMini, anything supplying between 4 and 12 volts should
239 work fine (like a standard 9V battery), but if you are planning
240 to fire pyro charges, ground testing is required to verify that
241 the battery supplies enough current.
244 The other active device in the starter kit is the TeleDongle USB to
245 RF interface. If you plug it in to your Mac or Linux computer it should
246 "just work", showing up as a serial port device. Windows systems need
247 driver information that is part of the AltOS download to know that the
248 existing USB modem driver will work. We therefore recommend installing
249 our software before plugging in TeleDongle if you are using a Windows
250 computer. If you are using Linux and are having problems, try moving
251 to a fresher kernel (2.6.33 or newer), as the USB serial driver had
252 ugly bugs in some earlier versions.
255 Next you should obtain and install the AltOS software. These
256 include the AltosUI ground station program, current firmware
257 images for all of the hardware, and a number of standalone
258 utilities that are rarely needed. Pre-built binary packages are
259 available for Linux, Microsoft Windows, and recent MacOSX
260 versions. Full source code and build instructions are also
261 available. The latest version may always be downloaded from
262 <ulink url="http://altusmetrum.org/AltOS"/>.
265 If you're using a TeleBT instead of the TeleDongle, you'll want
266 to go install the Altos Droid application from the Google Play
267 store. You don't need a data plan to use Altos Droid, but
268 without network access, the Map view will be less useful as it
269 won't contain any map data. You can also use TeleBT connected
270 over USB with your laptop computer; it acts exactly like a
271 TeleDongle. Anywhere this manual talks about TeleDongle, you can
272 also read that as 'and TeleBT when connected via USB'.
276 <title>Handling Precautions</title>
278 All Altus Metrum products are sophisticated electronic devices.
279 When handled gently and properly installed in an air-frame, they
280 will deliver impressive results. However, as with all electronic
281 devices, there are some precautions you must take.
284 The Lithium Polymer rechargeable batteries have an
285 extraordinary power density. This is great because we can fly with
286 much less battery mass than if we used alkaline batteries or previous
287 generation rechargeable batteries... but if they are punctured
288 or their leads are allowed to short, they can and will release their
290 Thus we recommend that you take some care when handling our batteries
291 and consider giving them some extra protection in your air-frame. We
292 often wrap them in suitable scraps of closed-cell packing foam before
293 strapping them down, for example.
296 The barometric sensors used on all of our flight computers are
297 sensitive to sunlight. In normal mounting situations, the baro sensor
298 and all of the other surface mount components
299 are "down" towards whatever the underlying mounting surface is, so
300 this is not normally a problem. Please consider this, though, when
301 designing an installation, for example, in an air-frame with a
302 see-through plastic payload bay. It is particularly important to
303 consider this with TeleMini v1.0, both because the baro sensor is on the
304 "top" of the board, and because many model rockets with payload bays
305 use clear plastic for the payload bay! Replacing these with an opaque
306 cardboard tube, painting them, or wrapping them with a layer of masking
307 tape are all reasonable approaches to keep the sensor out of direct
311 The barometric sensor sampling port must be able to "breathe",
312 both by not being covered by foam or tape or other materials that might
313 directly block the hole on the top of the sensor, and also by having a
314 suitable static vent to outside air.
317 As with all other rocketry electronics, Altus Metrum altimeters must
318 be protected from exposure to corrosive motor exhaust and ejection
323 <title>Hardware Overview</title>
325 TeleMetrum is a 1 inch by 2¾ inch circuit board. It was designed to
326 fit inside coupler for 29mm air-frame tubing, but using it in a tube that
327 small in diameter may require some creativity in mounting and wiring
328 to succeed! The presence of an accelerometer means TeleMetrum should
329 be aligned along the flight axis of the airframe, and by default the 1/4
330 wave UHF wire antenna should be on the nose-cone end of the board. The
331 antenna wire is about 7 inches long, and wiring for a power switch and
332 the e-matches for apogee and main ejection charges depart from the
333 fin can end of the board, meaning an ideal "simple" avionics
334 bay for TeleMetrum should have at least 10 inches of interior length.
337 TeleMini v1.0 is a ½ inch by 1½ inch circuit board. It was designed to
338 fit inside an 18mm air-frame tube, but using it in a tube that
339 small in diameter may require some creativity in mounting and wiring
340 to succeed! Since there is no accelerometer, TeleMini can be mounted
341 in any convenient orientation. The default ¼
342 wave UHF wire antenna attached to the center of one end of
343 the board is about 7 inches long, and wiring for a power switch and
344 the e-matches for apogee and main ejection charges depart from the
345 other end of the board, meaning an ideal "simple" avionics
346 bay for TeleMini should have at least 9 inches of interior length.
349 TeleMini v2.0 and EasyMini are both built on a 0.8 inch by 1½
350 inch circuit board. They're designed to fit in a 24mm coupler
351 tube. TeleMini has an antenna, which must be run straight out
352 fro the board. Bending or folding it will dramatically reduce RF
353 performance. For smaller rockets, it's often best to drill a
354 hole in the bulkhead forward of TeleMini and run the antenna
355 wire through that and alongside any recovery components
356 there. Be careful to seal the hole to prevent ejection gasses
357 from passing through the hole and damaging the electronics.
360 TeleMega is a 1¼ inch by 3¼ inch circuit board. It was
361 designed to easily fit in a 38mm coupler. Like TeleMetrum,
362 TeleMega has an accelerometer and so it must be mounted so that
363 the board is aligned with the flight axis. It can be mounted
364 either antenna up or down.
367 A typical installation involves attaching
368 only a suitable battery, a single pole switch for
369 power on/off, and two pairs of wires connecting e-matches for the
370 apogee and main ejection charges. All Altus Metrum products are
371 designed for use with single-cell batteries with 3.7 volts
372 nominal. TeleMini v2.0 and EasyMini may also be used with other
373 batteries as long as they supply between 4 and 12 volts.
376 The battery connectors are a standard 2-pin JST connector and
377 match batteries sold by Spark Fun. These batteries are
378 single-cell Lithium Polymer batteries that nominally provide 3.7
379 volts. Other vendors sell similar batteries for RC aircraft
380 using mating connectors, however the polarity for those is
381 generally reversed from the batteries used by Altus Metrum
382 products. In particular, the Tenergy batteries supplied for use
383 in Featherweight flight computers are not compatible with Altus
384 Metrum flight computers or battery chargers. <emphasis>Check
385 polarity and voltage before connecting any battery not purchased
386 from Altus Metrum or Spark Fun.</emphasis>
389 By default, we use the unregulated output of the battery directly
390 to fire ejection charges. This works marvelously with standard
391 low-current e-matches like the J-Tek from MJG Technologies, and with
392 Quest Q2G2 igniters. However, if you want or need to use a separate
393 pyro battery, check out the "External Pyro Battery" section in this
394 manual for instructions on how to wire that up. The altimeters are
395 designed to work with an external pyro battery of no more than 15 volts.
398 Ejection charges are wired directly to the screw terminal block
399 at the aft end of the altimeter. You'll need a very small straight
400 blade screwdriver for these screws, such as you might find in a
401 jeweler's screwdriver set.
404 Except for TeleMini v1.0, the flight computers also use the
405 screw terminal block for the power switch leads. On TeleMini v1.0,
406 the power switch leads are soldered directly to the board and
407 can be connected directly to a switch.
410 For most air-frames, the integrated antennas are more than
411 adequate. However, if you are installing in a carbon-fiber or
412 metal electronics bay which is opaque to RF signals, you may need to
413 use off-board external antennas instead. In this case, you can
414 order an altimeter with an SMA connector for the UHF antenna
415 connection, and, on TeleMetrum v1, you can unplug the integrated GPS
416 antenna and select an appropriate off-board GPS antenna with
417 cable terminating in a U.FL connector.
421 <title>System Operation</title>
423 <title>Firmware Modes </title>
425 The AltOS firmware build for the altimeters has two
426 fundamental modes, "idle" and "flight". Which of these modes
427 the firmware operates in is determined at start up time. For
428 TeleMetrum, the mode is controlled by the orientation of the
429 rocket (well, actually the board, of course...) at the time
430 power is switched on. If the rocket is "nose up", then
431 TeleMetrum assumes it's on a rail or rod being prepared for
432 launch, so the firmware chooses flight mode. However, if the
433 rocket is more or less horizontal, the firmware instead enters
434 idle mode. Since TeleMini v2.0 and EasyMini don't have an
435 accelerometer we can use to determine orientation, "idle" mode
436 is selected if the board is connected via USB to a computer,
437 otherwise the board enters "flight" mode. TeleMini v1.0
438 selects "idle" mode if it receives a command packet within the
439 first five seconds of operation.
442 At power on, you will hear three beeps or see three flashes
443 ("S" in Morse code for start up) and then a pause while
444 the altimeter completes initialization and self test, and decides
445 which mode to enter next.
448 In flight or "pad" mode, the altimeter engages the flight
449 state machine, goes into transmit-only mode to
450 send telemetry, and waits for launch to be detected.
451 Flight mode is indicated by an "di-dah-dah-dit" ("P" for pad)
452 on the beeper or lights, followed by beeps or flashes
453 indicating the state of the pyrotechnic igniter continuity.
454 One beep/flash indicates apogee continuity, two beeps/flashes
455 indicate main continuity, three beeps/flashes indicate both
456 apogee and main continuity, and one longer "brap" sound or
457 rapidly alternating lights indicates no continuity. For a
458 dual deploy flight, make sure you're getting three beeps or
459 flashes before launching! For apogee-only or motor eject
460 flights, do what makes sense.
463 If idle mode is entered, you will hear an audible "di-dit" or
464 see two short flashes ("I" for idle), and the flight state
465 machine is disengaged, thus no ejection charges will fire.
466 The altimeters also listen for the radio link when in idle
467 mode for requests sent via TeleDongle. Commands can be issued
468 in idle mode over either USB or the radio link
469 equivalently. TeleMini v1.0 only has the radio link. Idle
470 mode is useful for configuring the altimeter, for extracting
471 data from the on-board storage chip after flight, and for
472 ground testing pyro charges.
475 One "neat trick" of particular value when TeleMetrum or TeleMega are used with
476 very large air-frames, is that you can power the board up while the
477 rocket is horizontal, such that it comes up in idle mode. Then you can
478 raise the air-frame to launch position, and issue a 'reset' command
479 via TeleDongle over the radio link to cause the altimeter to reboot and
480 come up in flight mode. This is much safer than standing on the top
481 step of a rickety step-ladder or hanging off the side of a launch
482 tower with a screw-driver trying to turn on your avionics before
486 TeleMini v1.0 is configured solely via the radio link. Of course, that
487 means you need to know the TeleMini radio configuration values
488 or you won't be able to communicate with it. For situations
489 when you don't have the radio configuration values, TeleMini v1.0
490 offers an 'emergency recovery' mode. In this mode, TeleMini is
491 configured as follows:
495 Sets the radio frequency to 434.550MHz
500 Sets the radio calibration back to the factory value.
505 Sets the callsign to N0CALL
510 Does not go to 'pad' mode after five seconds.
516 To get into 'emergency recovery' mode, first find the row of
517 four small holes opposite the switch wiring. Using a short
518 piece of small gauge wire, connect the outer two holes
519 together, then power TeleMini up. Once the red LED is lit,
520 disconnect the wire and the board should signal that it's in
521 'idle' mode after the initial five second startup period.
527 TeleMetrum and TeleMega include a complete GPS receiver. A
528 complete explanation of how GPS works is beyond the scope of
529 this manual, but the bottom line is that the GPS receiver
530 needs to lock onto at least four satellites to obtain a solid
531 3 dimensional position fix and know what time it is.
534 The flight computers provide backup power to the GPS chip any time a
535 battery is connected. This allows the receiver to "warm start" on
536 the launch rail much faster than if every power-on were a GPS
537 "cold start". In typical operations, powering up
538 on the flight line in idle mode while performing final air-frame
539 preparation will be sufficient to allow the GPS receiver to cold
540 start and acquire lock. Then the board can be powered down during
541 RSO review and installation on a launch rod or rail. When the board
542 is turned back on, the GPS system should lock very quickly, typically
543 long before igniter installation and return to the flight line are
548 <title>Controlling An Altimeter Over The Radio Link</title>
550 One of the unique features of the Altus Metrum system is the
551 ability to create a two way command link between TeleDongle
552 and an altimeter using the digital radio transceivers
553 built into each device. This allows you to interact with the
554 altimeter from afar, as if it were directly connected to the
558 Any operation which can be performed with a flight computer can
559 either be done with the device directly connected to the
560 computer via the USB cable, or through the radio
561 link. TeleMini v1.0 doesn't provide a USB connector and so it is
562 always communicated with over radio. Select the appropriate
563 TeleDongle device when the list of devices is presented and
564 AltosUI will interact with an altimeter over the radio link.
567 One oddity in the current interface is how AltosUI selects the
568 frequency for radio communications. Instead of providing
569 an interface to specifically configure the frequency, it uses
570 whatever frequency was most recently selected for the target
571 TeleDongle device in Monitor Flight mode. If you haven't ever
572 used that mode with the TeleDongle in question, select the
573 Monitor Flight button from the top level UI, and pick the
574 appropriate TeleDongle device. Once the flight monitoring
575 window is open, select the desired frequency and then close it
576 down again. All radio communications will now use that frequency.
581 Save Flight Data—Recover flight data from the rocket without
587 Configure altimeter apogee delays, main deploy heights
588 and additional pyro event conditions
589 to respond to changing launch conditions. You can also
590 'reboot' the altimeter. Use this to remotely enable the
591 flight computer by turning TeleMetrum or TeleMega on in "idle" mode,
592 then once the air-frame is oriented for launch, you can
593 reboot the altimeter and have it restart in pad mode
594 without having to climb the scary ladder.
599 Fire Igniters—Test your deployment charges without snaking
600 wires out through holes in the air-frame. Simply assemble the
601 rocket as if for flight with the apogee and main charges
602 loaded, then remotely command the altimeter to fire the
608 Operation over the radio link for configuring an altimeter, ground
609 testing igniters, and so forth uses the same RF frequencies as flight
610 telemetry. To configure the desired TeleDongle frequency, select
611 the monitor flight tab, then use the frequency selector and
612 close the window before performing other desired radio operations.
615 The flight computers only enable radio commanding in 'idle' mode.
616 TeleMetrum and TeleMega use the accelerometer to detect which orientation they
617 start up in, so make sure you have the flight computer lying horizontally when you turn
618 it on. Otherwise, it will start in 'pad' mode ready for
619 flight, and will not be listening for command packets from TeleDongle.
622 TeleMini listens for a command packet for five seconds after
623 first being turned on, if it doesn't hear anything, it enters
624 'pad' mode, ready for flight and will no longer listen for
625 command packets. The easiest way to connect to TeleMini is to
626 initiate the command and select the TeleDongle device. At this
627 point, the TeleDongle will be attempting to communicate with
628 the TeleMini. Now turn TeleMini on, and it should immediately
629 start communicating with the TeleDongle and the desired
630 operation can be performed.
633 You can monitor the operation of the radio link by watching the
634 lights on the devices. The red LED will flash each time a packet
635 is transmitted, while the green LED will light up on TeleDongle when
636 it is waiting to receive a packet from the altimeter.
640 <title>Ground Testing </title>
642 An important aspect of preparing a rocket using electronic deployment
643 for flight is ground testing the recovery system. Thanks
644 to the bi-directional radio link central to the Altus Metrum system,
645 this can be accomplished in a TeleMega, TeleMetrum or TeleMini equipped rocket
646 with less work than you may be accustomed to with other systems. It
650 Just prep the rocket for flight, then power up the altimeter
651 in "idle" mode (placing air-frame horizontal for TeleMetrum or TeleMega, or
652 selecting the Configure Altimeter tab for TeleMini). This will cause
653 the firmware to go into "idle" mode, in which the normal flight
654 state machine is disabled and charges will not fire without
655 manual command. You can now command the altimeter to fire the apogee
656 or main charges from a safe distance using your computer and
657 TeleDongle and the Fire Igniter tab to complete ejection testing.
661 <title>Radio Link </title>
663 The chip our boards are based on incorporates an RF transceiver, but
664 it's not a full duplex system... each end can only be transmitting or
665 receiving at any given moment. So we had to decide how to manage the
669 By design, the altimeter firmware listens for the radio link when
670 it's in "idle mode", which
671 allows us to use the radio link to configure the rocket, do things like
672 ejection tests, and extract data after a flight without having to
673 crack open the air-frame. However, when the board is in "flight
674 mode", the altimeter only
675 transmits and doesn't listen at all. That's because we want to put
676 ultimate priority on event detection and getting telemetry out of
678 the radio in case the rocket crashes and we aren't able to extract
682 We don't generally use a 'normal packet radio' mode like APRS because they're
683 just too inefficient. The GFSK modulation we use is FSK with the
684 base-band pulses passed through a
685 Gaussian filter before they go into the modulator to limit the
686 transmitted bandwidth. When combined with the hardware forward error
687 correction support in the cc1111 chip, this allows us to have a very
688 robust 38.4 kilobit data link with only 10 milliwatts of transmit
689 power, a whip antenna in the rocket, and a hand-held Yagi on the
690 ground. We've had flights to above 21k feet AGL with great reception,
691 and calculations suggest we should be good to well over 40k feet AGL
692 with a 5-element yagi on the ground. We hope to fly boards to higher
693 altitudes over time, and would of course appreciate customer feedback
694 on performance in higher altitude flights!
697 However, TeleMetrum v2.0 and TeleMega can send APRS if
698 desired, the interval between APRS packets can be
699 configured. As each APRS packet takes a full second to
700 transmit, we recommend an interval of at least 5 seconds.
704 <title>Configurable Parameters</title>
706 Configuring an Altus Metrum altimeter for flight is very
707 simple. Even on our baro-only TeleMini and EasyMini boards, the use of a Kalman
708 filter means there is no need to set a "mach delay". The few
709 configurable parameters can all be set using AltosUI over USB or
710 or radio link via TeleDongle.
713 <title>Radio Frequency</title>
715 Altus Metrum boards support radio frequencies in the 70cm
716 band. By default, the configuration interface provides a
717 list of 10 "standard" frequencies in 100kHz channels starting at
718 434.550MHz. However, the firmware supports use of
719 any 50kHz multiple within the 70cm band. At any given
720 launch, we highly recommend coordinating when and by whom each
721 frequency will be used to avoid interference. And of course, both
722 altimeter and TeleDongle must be configured to the same
723 frequency to successfully communicate with each other.
727 <title>Apogee Delay</title>
729 Apogee delay is the number of seconds after the altimeter detects flight
730 apogee that the drogue charge should be fired. In most cases, this
731 should be left at the default of 0. However, if you are flying
732 redundant electronics such as for an L3 certification, you may wish
733 to set one of your altimeters to a positive delay so that both
734 primary and backup pyrotechnic charges do not fire simultaneously.
737 The Altus Metrum apogee detection algorithm fires exactly at
738 apogee. If you are also flying an altimeter like the
739 PerfectFlite MAWD, which only supports selecting 0 or 1
740 seconds of apogee delay, you may wish to set the MAWD to 0
741 seconds delay and set the TeleMetrum to fire your backup 2
742 or 3 seconds later to avoid any chance of both charges
743 firing simultaneously. We've flown several air-frames this
744 way quite happily, including Keith's successful L3 cert.
748 <title>Main Deployment Altitude</title>
750 By default, the altimeter will fire the main deployment charge at an
751 elevation of 250 meters (about 820 feet) above ground. We think this
752 is a good elevation for most air-frames, but feel free to change this
753 to suit. In particular, if you are flying two altimeters, you may
755 deployment elevation for the backup altimeter to be something lower
756 than the primary so that both pyrotechnic charges don't fire
761 <title>Maximum Flight Log</title>
763 TeleMetrum version 1.1 and 1.2 have 2MB of on-board flash storage,
764 enough to hold over 40 minutes of data at full data rate
765 (100 samples/second). TeleMetrum 1.0 has 1MB of on-board
766 storage. As data are stored at a reduced rate during descent
767 (10 samples/second), there's plenty of space to store many
768 flights worth of data.
771 TeleMetrum v2.0 and TeleMega have 8MB of on-board flash stroage, enough to hold
774 The on-board flash is partitioned into separate flight logs,
775 each of a fixed maximum size. Increase the maximum size of
776 each log and you reduce the number of flights that can be
777 stored. Decrease the size and TeleMetrum can store more
781 All of the configuration data is also stored in the flash
782 memory, which consumes 64kB on TeleMetrum v1.1/v1.2 and 256B on
783 TeleMetrum v1.0. This configuration space is not available
784 for storing flight log data.
787 To compute the amount of space needed for a single flight,
788 you can multiply the expected ascent time (in seconds) by
789 800, multiply the expected descent time (in seconds) by 80
790 and add the two together. That will slightly under-estimate
791 the storage (in bytes) needed for the flight. For instance,
792 a flight spending 20 seconds in ascent and 150 seconds in
793 descent will take about (20 * 800) + (150 * 80) = 28000
794 bytes of storage. You could store dozens of these flights in
798 The default size, 192kB, allows for 10 flights of storage on
799 TeleMetrum v1.1/v1.2 and 5 flights on TeleMetrum v1.0. This
800 ensures that you won't need to erase the memory before
801 flying each time while still allowing more than sufficient
802 storage for each flight.
805 As TeleMini does not contain an accelerometer, it stores
806 data at 10 samples per second during ascent and one sample
807 per second during descent. Each sample is a two byte reading
808 from the barometer. These are stored in 5kB of
809 on-chip flash memory which can hold 256 seconds at the
810 ascent rate or 2560 seconds at the descent rate. Because of
811 the limited storage, TeleMini cannot hold data for more than
812 one flight, and so must be erased after each flight or it
813 will not capture data for subsequent flights.
817 <title>Ignite Mode</title>
819 Instead of firing one charge at apogee and another charge at
820 a fixed height above the ground, you can configure the
821 altimeter to fire both at apogee or both during
822 descent. This was added to support an airframe that has two
823 TeleMetrum computers, one in the fin can and one in the
827 Providing the ability to use both igniters for apogee or
828 main allows some level of redundancy without needing two
829 flight computers. In Redundant Apogee or Redundant Main
830 mode, the two charges will be fired two seconds apart.
834 <title>Pad Orientation</title>
836 TeleMetrum measures acceleration along the axis of the
837 board. Which way the board is oriented affects the sign of
838 the acceleration value. Instead of trying to guess which way
839 the board is mounted in the air frame, TeleMetrum must be
840 explicitly configured for either Antenna Up or Antenna
841 Down. The default, Antenna Up, expects the end of the
842 TeleMetrum board connected to the 70cm antenna to be nearest
843 the nose of the rocket, with the end containing the screw
844 terminals nearest the tail.
852 <title>AltosUI</title>
854 The AltosUI program provides a graphical user interface for
855 interacting with the Altus Metrum product family, including
856 TeleMetrum, TeleMini and TeleDongle. AltosUI can monitor telemetry data,
857 configure TeleMetrum, TeleMini and TeleDongle devices and many other
858 tasks. The primary interface window provides a selection of
859 buttons, one for each major activity in the system. This manual
860 is split into chapters, each of which documents one of the tasks
861 provided from the top-level toolbar.
864 <title>Monitor Flight</title>
865 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
867 Selecting this item brings up a dialog box listing all of the
868 connected TeleDongle devices. When you choose one of these,
869 AltosUI will create a window to display telemetry data as
870 received by the selected TeleDongle device.
873 All telemetry data received are automatically recorded in
874 suitable log files. The name of the files includes the current
875 date and rocket serial and flight numbers.
878 The radio frequency being monitored by the TeleDongle device is
879 displayed at the top of the window. You can configure the
880 frequency by clicking on the frequency box and selecting the desired
881 frequency. AltosUI remembers the last frequency selected for each
882 TeleDongle and selects that automatically the next time you use
886 Below the TeleDongle frequency selector, the window contains a few
887 significant pieces of information about the altimeter providing
888 the telemetry data stream:
892 <para>The configured call-sign</para>
895 <para>The device serial number</para>
898 <para>The flight number. Each altimeter remembers how many
904 The rocket flight state. Each flight passes through several
905 states including Pad, Boost, Fast, Coast, Drogue, Main and
911 The Received Signal Strength Indicator value. This lets
912 you know how strong a signal TeleDongle is receiving. The
913 radio inside TeleDongle operates down to about -99dBm;
914 weaker signals may not be receivable. The packet link uses
915 error detection and correction techniques which prevent
916 incorrect data from being reported.
921 The age of the displayed data, in seconds since the last
922 successfully received telemetry packet. In normal operation
923 this will stay in the low single digits. If the number starts
924 counting up, then you are no longer receiving data over the radio
925 link from the flight computer.
930 Finally, the largest portion of the window contains a set of
931 tabs, each of which contain some information about the rocket.
932 They're arranged in 'flight order' so that as the flight
933 progresses, the selected tab automatically switches to display
934 data relevant to the current state of the flight. You can select
935 other tabs at any time. The final 'table' tab displays all of
936 the raw telemetry values in one place in a spreadsheet-like format.
939 <title>Launch Pad</title>
941 The 'Launch Pad' tab shows information used to decide when the
942 rocket is ready for flight. The first elements include red/green
943 indicators, if any of these is red, you'll want to evaluate
944 whether the rocket is ready to launch:
948 Battery Voltage. This indicates whether the Li-Po battery
949 powering the TeleMetrum has sufficient charge to last for
950 the duration of the flight. A value of more than
951 3.7V is required for a 'GO' status.
956 Apogee Igniter Voltage. This indicates whether the apogee
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 Main Igniter Voltage. This indicates whether the main
966 igniter has continuity. If the igniter has a low
967 resistance, then the voltage measured here will be close
968 to the Li-Po battery voltage. A value greater than 3.2V is
969 required for a 'GO' status.
974 On-board Data Logging. This indicates whether there is
975 space remaining on-board to store flight data for the
976 upcoming flight. If you've downloaded data, but failed
977 to erase flights, there may not be any space
978 left. TeleMetrum can store multiple flights, depending
979 on the configured maximum flight log size. TeleMini
980 stores only a single flight, so it will need to be
981 downloaded and erased after each flight to capture
982 data. This only affects on-board flight logging; the
983 altimeter will still transmit telemetry and fire
984 ejection charges at the proper times.
989 GPS Locked. For a TeleMetrum device, this indicates whether the GPS receiver is
990 currently able to compute position information. GPS requires
991 at least 4 satellites to compute an accurate position.
996 GPS Ready. For a TeleMetrum device, this indicates whether GPS has reported at least
997 10 consecutive positions without losing lock. This ensures
998 that the GPS receiver has reliable reception from the
1005 The Launchpad tab also shows the computed launch pad position
1006 and altitude, averaging many reported positions to improve the
1007 accuracy of the fix.
1011 <title>Ascent</title>
1013 This tab is shown during Boost, Fast and Coast
1014 phases. The information displayed here helps monitor the
1015 rocket as it heads towards apogee.
1018 The height, speed and acceleration are shown along with the
1019 maximum values for each of them. This allows you to quickly
1020 answer the most commonly asked questions you'll hear during
1024 The current latitude and longitude reported by the TeleMetrum GPS are
1025 also shown. Note that under high acceleration, these values
1026 may not get updated as the GPS receiver loses position
1027 fix. Once the rocket starts coasting, the receiver should
1028 start reporting position again.
1031 Finally, the current igniter voltages are reported as in the
1032 Launch Pad tab. This can help diagnose deployment failures
1033 caused by wiring which comes loose under high acceleration.
1037 <title>Descent</title>
1039 Once the rocket has reached apogee and (we hope) activated the
1040 apogee charge, attention switches to tracking the rocket on
1041 the way back to the ground, and for dual-deploy flights,
1042 waiting for the main charge to fire.
1045 To monitor whether the apogee charge operated correctly, the
1046 current descent rate is reported along with the current
1047 height. Good descent rates vary based on the choice of recovery
1048 components, but generally range from 15-30m/s on drogue and should
1049 be below 10m/s when under the main parachute in a dual-deploy flight.
1052 For TeleMetrum altimeters, you can locate the rocket in the
1053 sky using the elevation and bearing information to figure
1054 out where to look. Elevation is in degrees above the
1055 horizon. Bearing is reported in degrees relative to true
1056 north. Range can help figure out how big the rocket will
1057 appear. Ground Distance shows how far it is to a point
1058 directly under the rocket and can help figure out where the
1059 rocket is likely to land. Note that all of these values are
1060 relative to the pad location. If the elevation is near 90°,
1061 the rocket is over the pad, not over you.
1064 Finally, the igniter voltages are reported in this tab as
1065 well, both to monitor the main charge as well as to see what
1066 the status of the apogee charge is. Note that some commercial
1067 e-matches are designed to retain continuity even after being
1068 fired, and will continue to show as green or return from red to
1073 <title>Landed</title>
1075 Once the rocket is on the ground, attention switches to
1076 recovery. While the radio signal is often lost once the
1077 rocket is on the ground, the last reported GPS position is
1078 generally within a short distance of the actual landing location.
1081 The last reported GPS position is reported both by
1082 latitude and longitude as well as a bearing and distance from
1083 the launch pad. The distance should give you a good idea of
1084 whether to walk or hitch a ride. Take the reported
1085 latitude and longitude and enter them into your hand-held GPS
1086 unit and have that compute a track to the landing location.
1089 Both TeleMini and TeleMetrum will continue to transmit RDF
1090 tones after landing, allowing you to locate the rocket by
1091 following the radio signal if necessary. You may need to get
1092 away from the clutter of the flight line, or even get up on
1093 a hill (or your neighbor's RV roof) to receive the RDF signal.
1096 The maximum height, speed and acceleration reported
1097 during the flight are displayed for your admiring observers.
1098 The accuracy of these immediate values depends on the quality
1099 of your radio link and how many packets were received.
1100 Recovering the on-board data after flight will likely yield
1101 more precise results.
1104 To get more detailed information about the flight, you can
1105 click on the 'Graph Flight' button which will bring up a
1106 graph window for the current flight.
1110 <title>Site Map</title>
1112 When the TeleMetrum has a GPS fix, the Site Map tab will map
1113 the rocket's position to make it easier for you to locate the
1114 rocket, both while it is in the air, and when it has landed. The
1115 rocket's state is indicated by color: white for pad, red for
1116 boost, pink for fast, yellow for coast, light blue for drogue,
1117 dark blue for main, and black for landed.
1120 The map's scale is approximately 3m (10ft) per pixel. The map
1121 can be dragged using the left mouse button. The map will attempt
1122 to keep the rocket roughly centered while data is being received.
1125 Images are fetched automatically via the Google Maps Static API,
1126 and cached on disk for reuse. If map images cannot be downloaded,
1127 the rocket's path will be traced on a dark gray background
1131 You can pre-load images for your favorite launch sites
1132 before you leave home; check out the 'Preload Maps' section below.
1137 <title>Save Flight Data</title>
1139 The altimeter records flight data to its internal flash memory.
1140 TeleMetrum data is recorded at a much higher rate than the telemetry
1141 system can handle, and is not subject to radio drop-outs. As
1142 such, it provides a more complete and precise record of the
1143 flight. The 'Save Flight Data' button allows you to read the
1144 flash memory and write it to disk. As TeleMini has only a barometer, it
1145 records data at the same rate as the telemetry signal, but there will be
1146 no data lost due to telemetry drop-outs.
1149 Clicking on the 'Save Flight Data' button brings up a list of
1150 connected TeleMetrum and TeleDongle devices. If you select a
1151 TeleMetrum device, the flight data will be downloaded from that
1152 device directly. If you select a TeleDongle device, flight data
1153 will be downloaded from an altimeter over radio link via the
1154 specified TeleDongle. See the chapter on Controlling An Altimeter
1155 Over The Radio Link for more information.
1158 After the device has been selected, a dialog showing the
1159 flight data saved in the device will be shown allowing you to
1160 select which flights to download and which to delete. With
1161 version 0.9 or newer firmware, you must erase flights in order
1162 for the space they consume to be reused by another
1163 flight. This prevents accidentally losing flight data
1164 if you neglect to download data before flying again. Note that
1165 if there is no more space available in the device, then no
1166 data will be recorded during the next flight.
1169 The file name for each flight log is computed automatically
1170 from the recorded flight date, altimeter serial number and
1171 flight number information.
1175 <title>Replay Flight</title>
1177 Select this button and you are prompted to select a flight
1178 record file, either a .telem file recording telemetry data or a
1179 .eeprom file containing flight data saved from the altimeter
1183 Once a flight record is selected, the flight monitor interface
1184 is displayed and the flight is re-enacted in real time. Check
1185 the Monitor Flight chapter above to learn how this window operates.
1189 <title>Graph Data</title>
1191 Select this button and you are prompted to select a flight
1192 record file, either a .telem file recording telemetry data or a
1193 .eeprom file containing flight data saved from
1197 Once a flight record is selected, a window with four tabs is
1198 opened. The first tab contains a graph with acceleration
1199 (blue), velocity (green) and altitude (red) of the flight,
1200 measured in metric units. The apogee(yellow) and main(magenta)
1201 igniter voltages are also displayed; high voltages indicate
1202 continuity, low voltages indicate open circuits. The second
1203 tab lets you configure which data to show in the graph. The
1204 third contains some basic flight statistics while the fourth
1205 has a map with the ground track of the flight displayed.
1208 The graph can be zoomed into a particular area by clicking and
1209 dragging down and to the right. Once zoomed, the graph can be
1210 reset by clicking and dragging up and to the left. Holding down
1211 control and clicking and dragging allows the graph to be panned.
1212 The right mouse button causes a pop-up menu to be displayed, giving
1213 you the option save or print the plot.
1216 Note that telemetry files will generally produce poor graphs
1217 due to the lower sampling rate and missed telemetry packets.
1218 Use saved flight data in .eeprom files for graphing where possible.
1222 <title>Export Data</title>
1224 This tool takes the raw data files and makes them available for
1225 external analysis. When you select this button, you are prompted to
1227 data file (either .eeprom or .telem will do, remember that
1228 .eeprom files contain higher resolution and more continuous
1229 data). Next, a second dialog appears which is used to select
1230 where to write the resulting file. It has a selector to choose
1231 between CSV and KML file formats.
1234 <title>Comma Separated Value Format</title>
1236 This is a text file containing the data in a form suitable for
1237 import into a spreadsheet or other external data analysis
1238 tool. The first few lines of the file contain the version and
1239 configuration information from the altimeter, then
1240 there is a single header line which labels all of the
1241 fields. All of these lines start with a '#' character which
1242 many tools can be configured to skip over.
1245 The remaining lines of the file contain the data, with each
1246 field separated by a comma and at least one space. All of
1247 the sensor values are converted to standard units, with the
1248 barometric data reported in both pressure, altitude and
1249 height above pad units.
1253 <title>Keyhole Markup Language (for Google Earth)</title>
1255 This is the format used by Google Earth to provide an overlay
1256 within that application. With this, you can use Google Earth to
1257 see the whole flight path in 3D.
1262 <title>Configure Altimeter</title>
1264 Select this button and then select either a TeleMetrum or
1265 TeleDongle Device from the list provided. Selecting a TeleDongle
1266 device will use the radio link to configure a remote altimeter.
1269 The first few lines of the dialog provide information about the
1270 connected device, including the product name,
1271 software version and hardware serial number. Below that are the
1272 individual configuration entries.
1275 At the bottom of the dialog, there are four buttons:
1280 Save. This writes any changes to the
1281 configuration parameter block in flash memory. If you don't
1282 press this button, any changes you make will be lost.
1287 Reset. This resets the dialog to the most recently saved values,
1288 erasing any changes you have made.
1293 Reboot. This reboots the device. Use this to
1294 switch from idle to pad mode by rebooting once the rocket is
1295 oriented for flight, or to confirm changes you think you saved
1301 Close. This closes the dialog. Any unsaved changes will be
1307 The rest of the dialog contains the parameters to be configured.
1310 <title>Main Deploy Altitude</title>
1312 This sets the altitude (above the recorded pad altitude) at
1313 which the 'main' igniter will fire. The drop-down menu shows
1314 some common values, but you can edit the text directly and
1315 choose whatever you like. If the apogee charge fires below
1316 this altitude, then the main charge will fire two seconds
1317 after the apogee charge fires.
1321 <title>Apogee Delay</title>
1323 When flying redundant electronics, it's often important to
1324 ensure that multiple apogee charges don't fire at precisely
1325 the same time, as that can over pressurize the apogee deployment
1326 bay and cause a structural failure of the air-frame. The Apogee
1327 Delay parameter tells the flight computer to fire the apogee
1328 charge a certain number of seconds after apogee has been
1333 <title>Radio Frequency</title>
1335 This configures which of the configured frequencies to use for both
1336 telemetry and packet command mode. Note that if you set this
1337 value via packet command mode, you will have to reconfigure
1338 the TeleDongle frequency before you will be able to use packet
1343 <title>Radio Calibration</title>
1345 The radios in every Altus Metrum device are calibrated at the
1346 factory to ensure that they transmit and receive on the
1347 specified frequency. If you need to you can adjust the calibration
1348 by changing this value. Do not do this without understanding what
1349 the value means, read the appendix on calibration and/or the source
1350 code for more information. To change a TeleDongle's calibration,
1351 you must reprogram the unit completely.
1355 <title>Callsign</title>
1357 This sets the call sign included in each telemetry packet. Set this
1358 as needed to conform to your local radio regulations.
1362 <title>Maximum Flight Log Size</title>
1364 This sets the space (in kilobytes) allocated for each flight
1365 log. The available space will be divided into chunks of this
1366 size. A smaller value will allow more flights to be stored,
1367 a larger value will record data from longer flights.
1371 <title>Ignite Mode</title>
1373 TeleMetrum and TeleMini provide two igniter channels as they
1374 were originally designed as dual-deploy flight
1375 computers. This configuration parameter allows the two
1376 channels to be used in different configurations.
1381 Dual Deploy. This is the usual mode of operation; the
1382 'apogee' channel is fired at apogee and the 'main'
1383 channel at the height above ground specified by the
1384 'Main Deploy Altitude' during descent.
1389 Redundant Apogee. This fires both channels at
1390 apogee, the 'apogee' channel first followed after a two second
1391 delay by the 'main' channel.
1396 Redundant Main. This fires both channels at the
1397 height above ground specified by the Main Deploy
1398 Altitude setting during descent. The 'apogee'
1399 channel is fired first, followed after a two second
1400 delay by the 'main' channel.
1406 <title>Pad Orientation</title>
1408 Because it includes an accelerometer, TeleMetrum is
1409 sensitive to the orientation of the board. By default, it
1410 expects the antenna end to point forward. This parameter
1411 allows that default to be changed, permitting the board to
1412 be mounted with the antenna pointing aft instead.
1417 Antenna Up. In this mode, the antenna end of the
1418 TeleMetrum board must point forward, in line with the
1419 expected flight path.
1424 Antenna Down. In this mode, the antenna end of the
1425 TeleMetrum board must point aft, in line with the
1426 expected flight path.
1433 <title>Configure AltosUI</title>
1435 This button presents a dialog so that you can configure the AltosUI global settings.
1438 <title>Voice Settings</title>
1440 AltosUI provides voice announcements during flight so that you
1441 can keep your eyes on the sky and still get information about
1442 the current flight status. However, sometimes you don't want
1447 <para>Enable—turns all voice announcements on and off</para>
1451 Test Voice—Plays a short message allowing you to verify
1452 that the audio system is working and the volume settings
1459 <title>Log Directory</title>
1461 AltosUI logs all telemetry data and saves all TeleMetrum flash
1462 data to this directory. This directory is also used as the
1463 staring point when selecting data files for display or export.
1466 Click on the directory name to bring up a directory choosing
1467 dialog, select a new directory and click 'Select Directory' to
1468 change where AltosUI reads and writes data files.
1472 <title>Callsign</title>
1474 This value is transmitted in each command packet sent from
1475 TeleDongle and received from an altimeter. It is not used in
1476 telemetry mode, as the callsign configured in the altimeter board
1477 is included in all telemetry packets. Configure this
1478 with the AltosUI operators call sign as needed to comply with
1479 your local radio regulations.
1482 Note that to successfully command a flight computer over the radio
1483 (to configure the altimeter, monitor idle, or fire pyro charges),
1484 the callsign configured here must exactly match the callsign
1485 configured in the flight computer. This matching is case
1490 <title>Imperial Units</title>
1492 This switches between metric units (meters) and imperial
1493 units (feet and miles). This affects the display of values
1494 use during flight monitoring, data graphing and all of the
1495 voice announcements. It does not change the units used when
1496 exporting to CSV files, those are always produced in metric units.
1500 <title>Font Size</title>
1502 Selects the set of fonts used in the flight monitor
1503 window. Choose between the small, medium and large sets.
1507 <title>Serial Debug</title>
1509 This causes all communication with a connected device to be
1510 dumped to the console from which AltosUI was started. If
1511 you've started it from an icon or menu entry, the output
1512 will simply be discarded. This mode can be useful to debug
1513 various serial communication issues.
1517 <title>Manage Frequencies</title>
1519 This brings up a dialog where you can configure the set of
1520 frequencies shown in the various frequency menus. You can
1521 add as many as you like, or even reconfigure the default
1522 set. Changing this list does not affect the frequency
1523 settings of any devices, it only changes the set of
1524 frequencies shown in the menus.
1529 <title>Configure Groundstation</title>
1531 Select this button and then select a TeleDongle Device from the list provided.
1534 The first few lines of the dialog provide information about the
1535 connected device, including the product name,
1536 software version and hardware serial number. Below that are the
1537 individual configuration entries.
1540 Note that the TeleDongle itself doesn't save any configuration
1541 data, the settings here are recorded on the local machine in
1542 the Java preferences database. Moving the TeleDongle to
1543 another machine, or using a different user account on the same
1544 machine will cause settings made here to have no effect.
1547 At the bottom of the dialog, there are three buttons:
1552 Save. This writes any changes to the
1553 local Java preferences file. If you don't
1554 press this button, any changes you make will be lost.
1559 Reset. This resets the dialog to the most recently saved values,
1560 erasing any changes you have made.
1565 Close. This closes the dialog. Any unsaved changes will be
1571 The rest of the dialog contains the parameters to be configured.
1574 <title>Frequency</title>
1576 This configures the frequency to use for both telemetry and
1577 packet command mode. Set this before starting any operation
1578 involving packet command mode so that it will use the right
1579 frequency. Telemetry monitoring mode also provides a menu to
1580 change the frequency, and that menu also sets the same Java
1581 preference value used here.
1585 <title>Radio Calibration</title>
1587 The radios in every Altus Metrum device are calibrated at the
1588 factory to ensure that they transmit and receive on the
1589 specified frequency. To change a TeleDongle's calibration,
1590 you must reprogram the unit completely, so this entry simply
1591 shows the current value and doesn't allow any changes.
1596 <title>Flash Image</title>
1598 This reprograms any Altus Metrum device by using a TeleMetrum
1599 or TeleDongle as a programming dongle. Please read the
1600 directions for flashing devices in the Updating Device
1601 Firmware chapter below.
1604 Once you have the programmer and target devices connected,
1605 push the 'Flash Image' button. That will present a dialog box
1606 listing all of the connected devices. Carefully select the
1607 programmer device, not the device to be programmed.
1610 Next, select the image to flash to the device. These are named
1611 with the product name and firmware version. The file selector
1612 will start in the directory containing the firmware included
1613 with the AltosUI package. Navigate to the directory containing
1614 the desired firmware if it isn't there.
1617 Next, a small dialog containing the device serial number and
1618 RF calibration values should appear. If these values are
1619 incorrect (possibly due to a corrupted image in the device),
1620 enter the correct values here.
1623 Finally, a dialog containing a progress bar will follow the
1624 programming process.
1627 When programming is complete, the target device will
1628 reboot. Note that if the target device is connected via USB, you
1629 will have to unplug it and then plug it back in for the USB
1630 connection to reset so that you can communicate with the device
1635 <title>Fire Igniter</title>
1637 This activates the igniter circuits in TeleMetrum to help test
1638 recovery systems deployment. Because this command can operate
1639 over the Packet Command Link, you can prepare the rocket as
1640 for flight and then test the recovery system without needing
1641 to snake wires inside the air-frame.
1644 Selecting the 'Fire Igniter' button brings up the usual device
1645 selection dialog. Pick the desired TeleDongle or TeleMetrum
1646 device. This brings up another window which shows the current
1647 continuity test status for both apogee and main charges.
1650 Next, select the desired igniter to fire. This will enable the
1654 Select the 'Arm' button. This enables the 'Fire' button. The
1655 word 'Arm' is replaced by a countdown timer indicating that
1656 you have 10 seconds to press the 'Fire' button or the system
1657 will deactivate, at which point you start over again at
1658 selecting the desired igniter.
1662 <title>Scan Channels</title>
1664 This listens for telemetry packets on all of the configured
1665 frequencies, displaying information about each device it
1666 receives a packet from. You can select which of the three
1667 telemetry formats should be tried; by default, it only listens
1668 for the standard telemetry packets used in v1.0 and later
1673 <title>Load Maps</title>
1675 Before heading out to a new launch site, you can use this to
1676 load satellite images in case you don't have internet
1677 connectivity at the site. This loads a fairly large area
1678 around the launch site, which should cover any flight you're likely to make.
1681 There's a drop-down menu of launch sites we know about; if
1682 your favorites aren't there, please let us know the lat/lon
1683 and name of the site. The contents of this list are actually
1684 downloaded at run-time, so as new sites are sent in, they'll
1685 get automatically added to this list.
1688 If the launch site isn't in the list, you can manually enter the lat/lon values
1691 Clicking the 'Load Map' button will fetch images from Google
1692 Maps; note that Google limits how many images you can fetch at
1693 once, so if you load more than one launch site, you may get
1694 some gray areas in the map which indicate that Google is tired
1695 of sending data to you. Try again later.
1699 <title>Monitor Idle</title>
1701 This brings up a dialog similar to the Monitor Flight UI,
1702 except it works with the altimeter in "idle" mode by sending
1703 query commands to discover the current state rather than
1704 listening for telemetry packets.
1709 <title>AltosDroid</title>
1711 AltosDroid provides the same flight monitoring capabilities as
1712 AltosUI, but runs on Android devices and is designed to connect
1713 to a TeleBT receiver over Bluetooth™. Altos Droid monitors
1714 telemetry data, logging it to internal storage in the Android
1715 device, and presents that data in a UI the same way the 'Monitor
1716 Flight' window does in AltosUI.
1719 This manual will explain how to configure AltosDroid, connect
1720 to TeleBT, operate the flight monitoring interface and describe
1721 what the displayed data means.
1724 <title>Installing AltosDroid</title>
1726 AltosDroid is included in the Google Play store. To install
1727 it on your Android device, open open the Google Play Store
1728 application and search for "altosdroid". Make sure you don't
1729 have a space between "altos" and "droid" or you probably won't
1730 find what you want. That should bring you to the right page
1731 from which you can download and install the application.
1735 <title>Connecting to TeleBT</title>
1737 Press the Android 'Menu' button or soft-key to see the
1738 configuration options available. Select the 'Connect a device'
1739 option and then the 'Scan for devices' entry at the bottom to
1740 look for your TeleBT device. Select your device, and when it
1741 asks for the code, enter '1234'.
1744 Subsequent connections will not require you to enter that
1745 code, and your 'paired' device will appear in the list without
1750 <title>Configuring AltosDroid</title>
1752 The only configuration option available for AltosDroid is
1753 which frequency to listen on. Press the Android 'Menu' button
1754 or soft-key and pick the 'Select radio frequency' entry. That
1755 brings up a menu of pre-set radio frequencies; pick the one
1756 which matches your altimeter.
1760 <title>Altos Droid Flight Monitoring</title>
1762 Altos Droid is designed to mimic the AltosUI flight monitoring
1763 display, providing separate tabs for each stage of your rocket
1764 flight along with a tab containing a map of the local area
1765 with icons marking the current location of the altimeter and
1771 The 'Launch Pad' tab shows information used to decide when the
1772 rocket is ready for flight. The first elements include red/green
1773 indicators, if any of these is red, you'll want to evaluate
1774 whether the rocket is ready to launch:
1778 Battery Voltage. This indicates whether the Li-Po battery
1779 powering the TeleMetrum has sufficient charge to last for
1780 the duration of the flight. A value of more than
1781 3.7V is required for a 'GO' status.
1786 Apogee Igniter Voltage. This indicates whether the apogee
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 Main Igniter Voltage. This indicates whether the main
1796 igniter has continuity. If the igniter has a low
1797 resistance, then the voltage measured here will be close
1798 to the Li-Po battery voltage. A value greater than 3.2V is
1799 required for a 'GO' status.
1804 On-board Data Logging. This indicates whether there is
1805 space remaining on-board to store flight data for the
1806 upcoming flight. If you've downloaded data, but failed
1807 to erase flights, there may not be any space
1808 left. TeleMetrum can store multiple flights, depending
1809 on the configured maximum flight log size. TeleMini
1810 stores only a single flight, so it will need to be
1811 downloaded and erased after each flight to capture
1812 data. This only affects on-board flight logging; the
1813 altimeter will still transmit telemetry and fire
1814 ejection charges at the proper times.
1819 GPS Locked. For a TeleMetrum device, this indicates whether the GPS receiver is
1820 currently able to compute position information. GPS requires
1821 at least 4 satellites to compute an accurate position.
1826 GPS Ready. For a TeleMetrum device, this indicates whether GPS has reported at least
1827 10 consecutive positions without losing lock. This ensures
1828 that the GPS receiver has reliable reception from the
1835 The Launchpad tab also shows the computed launch pad position
1836 and altitude, averaging many reported positions to improve the
1837 accuracy of the fix.
1842 <title>Downloading Flight Logs</title>
1844 Altos Droid always saves every bit of telemetry data it
1845 receives. To download that to a computer for use with AltosUI,
1846 simply remove the SD card from your Android device, or connect
1847 your device to your computer's USB port and browse the files
1848 on that device. You will find '.telem' files in the TeleMetrum
1849 directory that will work with AltosUI directly.
1854 <title>Using Altus Metrum Products</title>
1856 <title>Being Legal</title>
1858 First off, in the US, you need an <ulink url="http://www.altusmetrum.org/Radio/">amateur radio license</ulink> or
1859 other authorization to legally operate the radio transmitters that are part
1864 <title>In the Rocket</title>
1866 In the rocket itself, you just need a <ulink url="http://www.altusmetrum.org/TeleMetrum/">TeleMetrum</ulink> or
1867 <ulink url="http://www.altusmetrum.org/TeleMini/">TeleMini</ulink> board and
1868 a single-cell, 3.7 volt nominal Li-Po rechargeable battery. An
1869 850mAh battery weighs less than a 9V alkaline battery, and will
1870 run a TeleMetrum for hours.
1871 A 110mAh battery weighs less than a triple A battery and will run a TeleMetrum for
1872 a few hours, or a TeleMini for much (much) longer.
1875 By default, we ship the altimeters with a simple wire antenna. If your
1876 electronics bay or the air-frame it resides within is made of carbon fiber,
1877 which is opaque to RF signals, you may choose to have an SMA connector
1878 installed so that you can run a coaxial cable to an antenna mounted
1879 elsewhere in the rocket.
1883 <title>On the Ground</title>
1885 To receive the data stream from the rocket, you need an antenna and short
1886 feed-line connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. If possible, use an SMA to BNC
1887 adapter instead of feedline between the antenna feedpoint and
1888 TeleDongle, as this will give you the best performance. The
1889 TeleDongle in turn plugs directly into the USB port on a notebook
1890 computer. Because TeleDongle looks like a simple serial port, your computer
1891 does not require special device drivers... just plug it in.
1894 The GUI tool, AltosUI, is written in Java and runs across
1895 Linux, Mac OS and Windows. There's also a suite of C tools
1896 for Linux which can perform most of the same tasks.
1899 After the flight, you can use the radio link to extract the more detailed data
1900 logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
1901 TeleMetrum board directly. Pulling out the data without having to open up
1902 the rocket is pretty cool! A USB cable is also how you charge the Li-Po
1903 battery, so you'll want one of those anyway... the same cable used by lots
1904 of digital cameras and other modern electronic stuff will work fine.
1907 If your TeleMetrum-equipped rocket lands out of sight, you may enjoy having a hand-held GPS
1908 receiver, so that you can put in a way-point for the last reported rocket
1909 position before touch-down. This makes looking for your rocket a lot like
1910 Geo-Caching... just go to the way-point and look around starting from there.
1913 You may also enjoy having a ham radio "HT" that covers the 70cm band... you
1914 can use that with your antenna to direction-find the rocket on the ground
1915 the same way you can use a Walston or Beeline tracker. This can be handy
1916 if the rocket is hiding in sage brush or a tree, or if the last GPS position
1917 doesn't get you close enough because the rocket dropped into a canyon, or
1918 the wind is blowing it across a dry lake bed, or something like that... Keith
1919 and Bdale both currently own and use the Yaesu VX-7R at launches.
1922 So, to recap, on the ground the hardware you'll need includes:
1923 <orderedlist inheritnum='inherit' numeration='arabic'>
1926 an antenna and feed-line or adapter
1941 optionally, a hand-held GPS receiver
1946 optionally, an HT or receiver covering 435 MHz
1952 The best hand-held commercial directional antennas we've found for radio
1953 direction finding rockets are from
1954 <ulink url="http://www.arrowantennas.com/" >
1957 The 440-3 and 440-5 are both good choices for finding a
1958 TeleMetrum- or TeleMini- equipped rocket when used with a suitable
1959 70cm HT. TeleDongle and an SMA to BNC adapter fit perfectly
1960 between the driven element and reflector of Arrow antennas.
1964 <title>Data Analysis</title>
1966 Our software makes it easy to log the data from each flight, both the
1967 telemetry received during the flight itself, and the more
1968 complete data log recorded in the flash memory on the altimeter
1969 board. Once this data is on your computer, our post-flight tools make it
1970 easy to quickly get to the numbers everyone wants, like apogee altitude,
1971 max acceleration, and max velocity. You can also generate and view a
1972 standard set of plots showing the altitude, acceleration, and
1973 velocity of the rocket during flight. And you can even export a TeleMetrum data file
1974 usable with Google Maps and Google Earth for visualizing the flight path
1975 in two or three dimensions!
1978 Our ultimate goal is to emit a set of files for each flight that can be
1979 published as a web page per flight, or just viewed on your local disk with
1984 <title>Future Plans</title>
1986 In the future, we intend to offer "companion boards" for the rocket
1987 that will plug in to TeleMetrum to collect additional data, provide
1988 more pyro channels, and so forth.
1991 Also under design is a new flight computer with more sensors, more
1992 pyro channels, and a more powerful radio system designed for use
1993 in multi-stage, complex, and extreme altitude projects.
1996 We are also working on alternatives to TeleDongle. One is a
1997 a stand-alone, hand-held ground terminal that will allow monitoring
1998 the rocket's status, collecting data during flight, and logging data
1999 after flight without the need for a notebook computer on the
2000 flight line. Particularly since it is so difficult to read most
2001 notebook screens in direct sunlight, we think this will be a great
2002 thing to have. We are also working on a TeleDongle variant with
2003 Bluetooth that will work with Android phones and tablets.
2006 Because all of our work is open, both the hardware designs and the
2007 software, if you have some great idea for an addition to the current
2008 Altus Metrum family, feel free to dive in and help! Or let us know
2009 what you'd like to see that we aren't already working on, and maybe
2010 we'll get excited about it too...
2014 <ulink url="http://altusmetrum.org/">web site</ulink> for more news
2015 and information as our family of products evolves!
2020 <title>Altimeter Installation Recommendations</title>
2022 Building high-power rockets that fly safely is hard enough. Mix
2023 in some sophisticated electronics and a bunch of radio energy
2024 and oftentimes you find few perfect solutions. This chapter
2025 contains some suggestions about how to install Altus Metrum
2026 products into the rocket air-frame, including how to safely and
2027 reliably mix a variety of electronics into the same air-frame.
2030 <title>Mounting the Altimeter</title>
2032 The first consideration is to ensure that the altimeter is
2033 securely fastened to the air-frame. For TeleMetrum, we use
2034 nylon standoffs and nylon screws; they're good to at least 50G
2035 and cannot cause any electrical issues on the board. For
2036 TeleMini, we usually cut small pieces of 1/16" balsa to fit
2037 under the screw holes, and then take 2x56 nylon screws and
2038 screw them through the TeleMini mounting holes, through the
2039 balsa and into the underlying material.
2041 <orderedlist inheritnum='inherit' numeration='arabic'>
2044 Make sure TeleMetrum is aligned precisely along the axis of
2045 acceleration so that the accelerometer can accurately
2046 capture data during the flight.
2051 Watch for any metal touching components on the
2052 board. Shorting out connections on the bottom of the board
2053 can cause the altimeter to fail during flight.
2059 <title>Dealing with the Antenna</title>
2061 The antenna supplied is just a piece of solid, insulated,
2062 wire. If it gets damaged or broken, it can be easily
2063 replaced. It should be kept straight and not cut; bending or
2064 cutting it will change the resonant frequency and/or
2065 impedance, making it a less efficient radiator and thus
2066 reducing the range of the telemetry signal.
2069 Keeping metal away from the antenna will provide better range
2070 and a more even radiation pattern. In most rockets, it's not
2071 entirely possible to isolate the antenna from metal
2072 components; there are often bolts, all-thread and wires from other
2073 electronics to contend with. Just be aware that the more stuff
2074 like this around the antenna, the lower the range.
2077 Make sure the antenna is not inside a tube made or covered
2078 with conducting material. Carbon fiber is the most common
2079 culprit here -- CF is a good conductor and will effectively
2080 shield the antenna, dramatically reducing signal strength and
2081 range. Metallic flake paint is another effective shielding
2082 material which is to be avoided around any antennas.
2085 If the ebay is large enough, it can be convenient to simply
2086 mount the altimeter at one end and stretch the antenna out
2087 inside. Taping the antenna to the sled can keep it straight
2088 under acceleration. If there are metal rods, keep the
2089 antenna as far away as possible.
2092 For a shorter ebay, it's quite practical to have the antenna
2093 run through a bulkhead and into an adjacent bay. Drill a small
2094 hole in the bulkhead, pass the antenna wire through it and
2095 then seal it up with glue or clay. We've also used acrylic
2096 tubing to create a cavity for the antenna wire. This works a
2097 bit better in that the antenna is known to stay straight and
2098 not get folded by recovery components in the bay. Angle the
2099 tubing towards the side wall of the rocket and it ends up
2100 consuming very little space.
2103 If you need to place the antenna at a distance from the
2104 altimeter, you can replace the antenna with an edge-mounted
2105 SMA connector, and then run 50Ω coax from the board to the
2106 antenna. Building a remote antenna is beyond the scope of this
2111 <title>Preserving GPS Reception</title>
2113 The GPS antenna and receiver in TeleMetrum are highly
2114 sensitive and normally have no trouble tracking enough
2115 satellites to provide accurate position information for
2116 recovering the rocket. However, there are many ways to
2117 attenuate the GPS signal.
2118 <orderedlist inheritnum='inherit' numeration='arabic'>
2121 Conductive tubing or coatings. Carbon fiber and metal
2122 tubing, or metallic paint will all dramatically attenuate the
2123 GPS signal. We've never heard of anyone successfully
2124 receiving GPS from inside these materials.
2129 Metal components near the GPS patch antenna. These will
2130 de-tune the patch antenna, changing the resonant frequency
2131 away from the L1 carrier and reduce the effectiveness of the
2132 antenna. You can place as much stuff as you like beneath the
2133 antenna as that's covered with a ground plane. But, keep
2134 wires and metal out from above the patch antenna.
2141 <title>Radio Frequency Interference</title>
2143 Any altimeter will generate RFI; the digital circuits use
2144 high-frequency clocks that spray radio interference across a
2145 wide band. Altus Metrum altimeters generate intentional radio
2146 signals as well, increasing the amount of RF energy around the board.
2149 Rocketry altimeters also use precise sensors measuring air
2150 pressure and acceleration. Tiny changes in voltage can cause
2151 these sensor readings to vary by a huge amount. When the
2152 sensors start mis-reporting data, the altimeter can either
2153 fire the igniters at the wrong time, or not fire them at all.
2156 Voltages are induced when radio frequency energy is
2157 transmitted from one circuit to another. Here are things that
2158 influence the induced voltage and current:
2163 Keep wires from different circuits apart. Moving circuits
2164 further apart will reduce RFI.
2169 Avoid parallel wires from different circuits. The longer two
2170 wires run parallel to one another, the larger the amount of
2171 transferred energy. Cross wires at right angles to reduce
2177 Twist wires from the same circuits. Two wires the same
2178 distance from the transmitter will get the same amount of
2179 induced energy which will then cancel out. Any time you have
2180 a wire pair running together, twist the pair together to
2181 even out distances and reduce RFI. For altimeters, this
2182 includes battery leads, switch hookups and igniter
2188 Avoid resonant lengths. Know what frequencies are present
2189 in the environment and avoid having wire lengths near a
2190 natural resonant length. Altusmetrum products transmit on the
2191 70cm amateur band, so you should avoid lengths that are a
2192 simple ratio of that length; essentially any multiple of 1/4
2193 of the wavelength (17.5cm).
2199 <title>The Barometric Sensor</title>
2201 Altusmetrum altimeters measure altitude with a barometric
2202 sensor, essentially measuring the amount of air above the
2203 rocket to figure out how high it is. A large number of
2204 measurements are taken as the altimeter initializes itself to
2205 figure out the pad altitude. Subsequent measurements are then
2206 used to compute the height above the pad.
2209 To accurately measure atmospheric pressure, the ebay
2210 containing the altimeter must be vented outside the
2211 air-frame. The vent must be placed in a region of linear
2212 airflow, have smooth edges, and away from areas of increasing or
2213 decreasing pressure.
2216 The barometric sensor in the altimeter is quite sensitive to
2217 chemical damage from the products of APCP or BP combustion, so
2218 make sure the ebay is carefully sealed from any compartment
2219 which contains ejection charges or motors.
2223 <title>Ground Testing</title>
2225 The most important aspect of any installation is careful
2226 ground testing. Bringing an air-frame up to the LCO table which
2227 hasn't been ground tested can lead to delays or ejection
2228 charges firing on the pad, or, even worse, a recovery system
2232 Do a 'full systems' test that includes wiring up all igniters
2233 without any BP and turning on all of the electronics in flight
2234 mode. This will catch any mistakes in wiring and any residual
2235 RFI issues that might accidentally fire igniters at the wrong
2236 time. Let the air-frame sit for several minutes, checking for
2237 adequate telemetry signal strength and GPS lock. If any igniters
2238 fire unexpectedly, find and resolve the issue before loading any
2242 Ground test the ejection charges. Prepare the rocket for
2243 flight, loading ejection charges and igniters. Completely
2244 assemble the air-frame and then use the 'Fire Igniters'
2245 interface through a TeleDongle to command each charge to
2246 fire. Make sure the charge is sufficient to robustly separate
2247 the air-frame and deploy the recovery system.
2252 <title>Updating Device Firmware</title>
2254 The big concept to understand is that you have to use a
2255 TeleDongle as a programmer to update a TeleMetrum or TeleMini,
2256 and a TeleMetrum or other TeleDongle to program the TeleDongle
2257 Due to limited memory resources in the cc1111, we don't support
2258 programming directly over USB.
2261 You may wish to begin by ensuring you have current firmware images.
2262 These are distributed as part of the AltOS software bundle that
2263 also includes the AltosUI ground station program. Newer ground
2264 station versions typically work fine with older firmware versions,
2265 so you don't need to update your devices just to try out new
2266 software features. You can always download the most recent
2267 version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
2270 We recommend updating the altimeter first, before updating TeleDongle.
2273 <title>Updating TeleMetrum Firmware</title>
2274 <orderedlist inheritnum='inherit' numeration='arabic'>
2277 Find the 'programming cable' that you got as part of the starter
2278 kit, that has a red 8-pin MicroMaTch connector on one end and a
2279 red 4-pin MicroMaTch connector on the other end.
2284 Take the 2 screws out of the TeleDongle case to get access
2285 to the circuit board.
2290 Plug the 8-pin end of the programming cable to the
2291 matching connector on the TeleDongle, and the 4-pin end to the
2292 matching connector on the TeleMetrum.
2293 Note that each MicroMaTch connector has an alignment pin that
2294 goes through a hole in the PC board when you have the cable
2300 Attach a battery to the TeleMetrum board.
2305 Plug the TeleDongle into your computer's USB port, and power
2311 Run AltosUI, and select 'Flash Image' from the File menu.
2316 Pick the TeleDongle device from the list, identifying it as the
2322 Select the image you want put on the TeleMetrum, which should have a
2323 name in the form telemetrum-v1.2-1.0.0.ihx. It should be visible
2324 in the default directory, if not you may have to poke around
2325 your system to find it.
2330 Make sure the configuration parameters are reasonable
2331 looking. If the serial number and/or RF configuration
2332 values aren't right, you'll need to change them.
2337 Hit the 'OK' button and the software should proceed to flash
2338 the TeleMetrum with new firmware, showing a progress bar.
2343 Confirm that the TeleMetrum board seems to have updated OK, which you
2344 can do by plugging in to it over USB and using a terminal program
2345 to connect to the board and issue the 'v' command to check
2351 If something goes wrong, give it another try.
2357 <title>Updating TeleMini Firmware</title>
2358 <orderedlist inheritnum='inherit' numeration='arabic'>
2361 You'll need a special 'programming cable' to reprogram the
2362 TeleMini. It's available on the Altus Metrum web store, or
2363 you can make your own using an 8-pin MicroMaTch connector on
2364 one end and a set of four pins on the other.
2369 Take the 2 screws out of the TeleDongle case to get access
2370 to the circuit board.
2375 Plug the 8-pin end of the programming cable to the matching
2376 connector on the TeleDongle, and the 4-pins into the holes
2377 in the TeleMini circuit board. Note that the MicroMaTch
2378 connector has an alignment pin that goes through a hole in
2379 the PC board when you have the cable oriented correctly, and
2380 that pin 1 on the TeleMini board is marked with a square pad
2381 while the other pins have round pads.
2386 Attach a battery to the TeleMini board.
2391 Plug the TeleDongle into your computer's USB port, and power
2397 Run AltosUI, and select 'Flash Image' from the File menu.
2402 Pick the TeleDongle device from the list, identifying it as the
2408 Select the image you want put on the TeleMini, which should have a
2409 name in the form telemini-v1.0-1.0.0.ihx. It should be visible
2410 in the default directory, if not you may have to poke around
2411 your system to find it.
2416 Make sure the configuration parameters are reasonable
2417 looking. If the serial number and/or RF configuration
2418 values aren't right, you'll need to change them.
2423 Hit the 'OK' button and the software should proceed to flash
2424 the TeleMini with new firmware, showing a progress bar.
2429 Confirm that the TeleMini board seems to have updated OK, which you
2430 can do by configuring it over the radio link through the TeleDongle, or
2431 letting it come up in "flight" mode and listening for telemetry.
2436 If something goes wrong, give it another try.
2442 <title>Updating TeleDongle Firmware</title>
2444 Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
2445 firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
2447 <orderedlist inheritnum='inherit' numeration='arabic'>
2450 Find the 'programming cable' that you got as part of the starter
2451 kit, that has a red 8-pin MicroMaTch connector on one end and a
2452 red 4-pin MicroMaTch connector on the other end.
2457 Find the USB cable that you got as part of the starter kit, and
2458 plug the "mini" end in to the mating connector on TeleMetrum or TeleDongle.
2463 Take the 2 screws out of the TeleDongle case to get access
2464 to the circuit board.
2469 Plug the 8-pin end of the programming cable to the
2470 matching connector on the programmer, and the 4-pin end to the
2471 matching connector on the TeleDongle.
2472 Note that each MicroMaTch connector has an alignment pin that
2473 goes through a hole in the PC board when you have the cable
2479 Attach a battery to the TeleMetrum board if you're using one.
2484 Plug both the programmer and the TeleDongle into your computer's USB
2485 ports, and power up the programmer.
2490 Run AltosUI, and select 'Flash Image' from the File menu.
2495 Pick the programmer device from the list, identifying it as the
2501 Select the image you want put on the TeleDongle, which should have a
2502 name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
2503 in the default directory, if not you may have to poke around
2504 your system to find it.
2509 Make sure the configuration parameters are reasonable
2510 looking. If the serial number and/or RF configuration
2511 values aren't right, you'll need to change them. The TeleDongle
2512 serial number is on the "bottom" of the circuit board, and can
2513 usually be read through the translucent blue plastic case without
2514 needing to remove the board from the case.
2519 Hit the 'OK' button and the software should proceed to flash
2520 the TeleDongle with new firmware, showing a progress bar.
2525 Confirm that the TeleDongle board seems to have updated OK, which you
2526 can do by plugging in to it over USB and using a terminal program
2527 to connect to the board and issue the 'v' command to check
2528 the version, etc. Once you're happy, remove the programming cable
2529 and put the cover back on the TeleDongle.
2534 If something goes wrong, give it another try.
2539 Be careful removing the programming cable from the locking 8-pin
2540 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
2541 screwdriver or knife blade to gently pry the locking ears out
2542 slightly to extract the connector. We used a locking connector on
2543 TeleMetrum to help ensure that the cabling to companion boards
2544 used in a rocket don't ever come loose accidentally in flight.
2549 <title>Hardware Specifications</title>
2551 <title>TeleMetrum Specifications</title>
2555 Recording altimeter for model rocketry.
2560 Supports dual deployment (can fire 2 ejection charges).
2565 70cm ham-band transceiver for telemetry down-link.
2570 Barometric pressure sensor good to 45k feet MSL.
2575 1-axis high-g accelerometer for motor characterization, capable of
2576 +/- 50g using default part.
2581 On-board, integrated GPS receiver with 5Hz update rate capability.
2586 On-board 1 megabyte non-volatile memory for flight data storage.
2591 USB interface for battery charging, configuration, and data recovery.
2596 Fully integrated support for Li-Po rechargeable batteries.
2601 Uses Li-Po to fire e-matches, can be modified to support
2602 optional separate pyro battery if needed.
2607 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
2613 <title>TeleMini Specifications</title>
2617 Recording altimeter for model rocketry.
2622 Supports dual deployment (can fire 2 ejection charges).
2627 70cm ham-band transceiver for telemetry down-link.
2632 Barometric pressure sensor good to 45k feet MSL.
2637 On-board 5 kilobyte non-volatile memory for flight data storage.
2642 RF interface for configuration, and data recovery.
2647 Support for Li-Po rechargeable batteries, using an external charger.
2652 Uses Li-Po to fire e-matches, can be modified to support
2653 optional separate pyro battery if needed.
2658 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube.
2667 TeleMetrum seems to shut off when disconnected from the
2668 computer. Make sure the battery is adequately charged. Remember the
2669 unit will pull more power than the USB port can deliver before the
2670 GPS enters "locked" mode. The battery charges best when TeleMetrum
2674 It's impossible to stop the TeleDongle when it's in "p" mode, I have
2675 to unplug the USB cable? Make sure you have tried to "escape out" of
2676 this mode. If this doesn't work the reboot procedure for the
2677 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
2678 outgoing buffer IF your "escape out" ('~~') does not work.
2679 At this point using either 'ao-view' (or possibly
2680 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
2684 The amber LED (on the TeleMetrum) lights up when both
2685 battery and USB are connected. Does this mean it's charging?
2686 Yes, the yellow LED indicates the charging at the 'regular' rate.
2687 If the led is out but the unit is still plugged into a USB port,
2688 then the battery is being charged at a 'trickle' rate.
2691 There are no "dit-dah-dah-dit" sound or lights like the manual mentions?
2692 That's the "pad" mode. Weak batteries might be the problem.
2693 It is also possible that the TeleMetrum is horizontal and the output
2694 is instead a "dit-dit" meaning 'idle'. For TeleMini, it's possible that
2695 it received a command packet which would have left it in "pad" mode.
2698 How do I save flight data?
2699 Live telemetry is written to file(s) whenever AltosUI is connected
2700 to the TeleDongle. The file area defaults to ~/TeleMetrum
2701 but is easily changed using the menus in AltosUI. The files that
2702 are written end in '.telem'. The after-flight
2703 data-dumped files will end in .eeprom and represent continuous data
2704 unlike the .telem files that are subject to losses
2705 along the RF data path.
2706 See the above instructions on what and how to save the eeprom stored
2707 data after physically retrieving your altimeter. Make sure to save
2708 the on-board data after each flight; while the TeleMetrum can store
2709 multiple flights, you never know when you'll lose the altimeter...
2713 <title>Notes for Older Software</title>
2716 Before AltosUI was written, using Altus Metrum devices required
2717 some finesse with the Linux command line. There was a limited
2718 GUI tool, ao-view, which provided functionality similar to the
2719 Monitor Flight window in AltosUI, but everything else was a
2720 fairly 80's experience. This appendix includes documentation for
2721 using that software.
2725 Both TeleMetrum and TeleDongle can be directly communicated
2726 with using USB ports. The first thing you should try after getting
2727 both units plugged into to your computer's USB port(s) is to run
2728 'ao-list' from a terminal-window to see what port-device-name each
2729 device has been assigned by the operating system.
2730 You will need this information to access the devices via their
2731 respective on-board firmware and data using other command line
2732 programs in the AltOS software suite.
2735 TeleMini can be communicated with through a TeleDongle device
2736 over the radio link. When first booted, TeleMini listens for a
2737 TeleDongle device and if it receives a packet, it goes into
2738 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be
2739 launched. The easiest way to get it talking is to start the
2740 communication link on the TeleDongle and the power up the
2744 To access the device's firmware for configuration you need a terminal
2745 program such as you would use to talk to a modem. The software
2746 authors prefer using the program 'cu' which comes from the UUCP package
2747 on most Unix-like systems such as Linux. An example command line for
2748 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
2749 indicated from running the
2750 ao-list program. Another reasonable terminal program for Linux is
2751 'cutecom'. The default 'escape'
2752 character used by CU (i.e. the character you use to
2753 issue commands to cu itself instead of sending the command as input
2754 to the connected device) is a '~'. You will need this for use in
2755 only two different ways during normal operations. First is to exit
2756 the program by sending a '~.' which is called a 'escape-disconnect'
2757 and allows you to close-out from 'cu'. The
2758 second use will be outlined later.
2761 All of the Altus Metrum devices share the concept of a two level
2762 command set in their firmware.
2763 The first layer has several single letter commands. Once
2764 you are using 'cu' (or 'cutecom') sending (typing) a '?'
2765 returns a full list of these
2766 commands. The second level are configuration sub-commands accessed
2767 using the 'c' command, for
2768 instance typing 'c?' will give you this second level of commands
2769 (all of which require the
2770 letter 'c' to access). Please note that most configuration options
2771 are stored only in Flash memory; TeleDongle doesn't provide any storage
2772 for these options and so they'll all be lost when you unplug it.
2775 Try setting these configuration ('c' or second level menu) values. A good
2776 place to start is by setting your call sign. By default, the boards
2777 use 'N0CALL' which is cute, but not exactly legal!
2778 Spend a few minutes getting comfortable with the units, their
2779 firmware, and 'cu' (or possibly 'cutecom').
2780 For instance, try to send
2781 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
2782 Verify you can connect and disconnect from the units while in your
2783 terminal program by sending the escape-disconnect mentioned above.
2786 To set the radio frequency, use the 'c R' command to specify the
2787 radio transceiver configuration parameter. This parameter is computed
2788 using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
2789 the standard calibration reference frequency, 'S', (normally 434.550MHz):
2793 Round the result to the nearest integer value.
2794 As with all 'c' sub-commands, follow this with a 'c w' to write the
2795 change to the parameter block in the on-board flash on
2796 your altimeter board if you want the change to stay in place across reboots.
2799 To set the apogee delay, use the 'c d' command.
2800 As with all 'c' sub-commands, follow this with a 'c w' to write the
2801 change to the parameter block in the on-board DataFlash chip.
2804 To set the main deployment altitude, use the 'c m' command.
2805 As with all 'c' sub-commands, follow this with a 'c w' to write the
2806 change to the parameter block in the on-board DataFlash chip.
2809 To calibrate the radio frequency, connect the UHF antenna port to a
2810 frequency counter, set the board to 434.550MHz, and use the 'C'
2811 command to generate a CW carrier. Wait for the transmitter temperature
2812 to stabilize and the frequency to settle down.
2813 Then, divide 434.550 MHz by the
2814 measured frequency and multiply by the current radio cal value show
2815 in the 'c s' command. For an unprogrammed board, the default value
2816 is 1186611. Take the resulting integer and program it using the 'c f'
2817 command. Testing with the 'C' command again should show a carrier
2818 within a few tens of Hertz of the intended frequency.
2819 As with all 'c' sub-commands, follow this with a 'c w' to write the
2820 change to the parameter block in the on-board DataFlash chip.
2823 Note that the 'reboot' command, which is very useful on the altimeters,
2824 will likely just cause problems with the dongle. The *correct* way
2825 to reset the dongle is just to unplug and re-plug it.
2828 A fun thing to do at the launch site and something you can do while
2829 learning how to use these units is to play with the radio link access
2830 between an altimeter and the TeleDongle. Be aware that you *must* create
2831 some physical separation between the devices, otherwise the link will
2832 not function due to signal overload in the receivers in each device.
2835 Now might be a good time to take a break and read the rest of this
2836 manual, particularly about the two "modes" that the altimeters
2837 can be placed in. TeleMetrum uses the position of the device when booting
2838 up will determine whether the unit is in "pad" or "idle" mode. TeleMini
2839 enters "idle" mode when it receives a command packet within the first 5 seconds
2840 of being powered up, otherwise it enters "pad" mode.
2843 You can access an altimeter in idle mode from the TeleDongle's USB
2844 connection using the radio link
2845 by issuing a 'p' command to the TeleDongle. Practice connecting and
2846 disconnecting ('~~' while using 'cu') from the altimeter. If
2847 you cannot escape out of the "p" command, (by using a '~~' when in
2848 CU) then it is likely that your kernel has issues. Try a newer version.
2851 Using this radio link allows you to configure the altimeter, test
2852 fire e-matches and igniters from the flight line, check pyro-match
2853 continuity and so forth. You can leave the unit turned on while it
2854 is in 'idle mode' and then place the
2855 rocket vertically on the launch pad, walk away and then issue a
2856 reboot command. The altimeter will reboot and start sending data
2857 having changed to the "pad" mode. If the TeleDongle is not receiving
2858 this data, you can disconnect 'cu' from the TeleDongle using the
2859 procedures mentioned above and THEN connect to the TeleDongle from
2860 inside 'ao-view'. If this doesn't work, disconnect from the
2861 TeleDongle, unplug it, and try again after plugging it back in.
2864 In order to reduce the chance of accidental firing of pyrotechnic
2865 charges, the command to fire a charge is intentionally somewhat
2866 difficult to type, and the built-in help is slightly cryptic to
2867 prevent accidental echoing of characters from the help text back at
2868 the board from firing a charge. The command to fire the apogee
2869 drogue charge is 'i DoIt drogue' and the command to fire the main
2870 charge is 'i DoIt main'.
2873 On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
2874 and 'ao-view' will both auditorily announce and visually indicate
2876 Now you can launch knowing that you have a good data path and
2877 good satellite lock for flight data and recovery. Remember
2878 you MUST tell ao-view to connect to the TeleDongle explicitly in
2879 order for ao-view to be able to receive data.
2882 The altimeters provide RDF (radio direction finding) tones on
2883 the pad, during descent and after landing. These can be used to
2884 locate the rocket using a directional antenna; the signal
2885 strength providing an indication of the direction from receiver to rocket.
2888 TeleMetrum also provides GPS tracking data, which can further simplify
2889 locating the rocket once it has landed. (The last good GPS data
2890 received before touch-down will be on the data screen of 'ao-view'.)
2893 Once you have recovered the rocket you can download the eeprom
2894 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
2895 either a USB cable or over the radio link using TeleDongle.
2896 And by following the man page for 'ao-postflight' you can create
2897 various data output reports, graphs, and even KML data to see the
2898 flight trajectory in Google-earth. (Moving the viewing angle making
2899 sure to connect the yellow lines while in Google-earth is the proper
2903 As for ao-view.... some things are in the menu but don't do anything
2904 very useful. The developers have stopped working on ao-view to focus
2905 on a new, cross-platform ground station program. So ao-view may or
2906 may not be updated in the future. Mostly you just use
2907 the Log and Device menus. It has a wonderful display of the incoming
2908 flight data and I am sure you will enjoy what it has to say to you
2909 once you enable the voice output!
2913 <title>Drill Templates</title>
2915 These images, when printed, provide precise templates for the
2916 mounting holes in Altus Metrum flight computers
2919 <title>TeleMetrum template</title>
2921 TeleMetrum has overall dimensions of 1.000 x 2.750 inches, and the
2922 mounting holes are sized for use with 4-40 or M3 screws.
2924 <mediaobject id="TeleMetrumTemplate">
2926 <imagedata format="SVG" fileref="telemetrum.svg"/>
2931 <title>TeleMini template</title>
2933 TeleMini has overall dimensions of 0.500 x 1.500 inches, and the
2934 mounting holes are sized for use with 2-56 or M2 screws.
2936 <mediaobject id="TeleMiniTemplate">
2938 <imagedata format="SVG" fileref="telemini.svg"/>
2944 <title>Calibration</title>
2946 There are only two calibrations required for a TeleMetrum board, and
2947 only one for TeleDongle and TeleMini. All boards are shipped from
2948 the factory pre-calibrated, but the procedures are documented here
2949 in case they are ever needed. Re-calibration is not supported by
2950 AltosUI, you must connect to the board with a serial terminal program
2951 and interact directly with the on-board command interpreter to effect
2955 <title>Radio Frequency</title>
2957 The radio frequency is synthesized from a clock based on the 48 MHz
2958 crystal on the board. The actual frequency of this oscillator
2959 must be measured to generate a calibration constant. While our
2961 bandwidth is wide enough to allow boards to communicate even when
2962 their oscillators are not on exactly the same frequency, performance
2963 is best when they are closely matched.
2964 Radio frequency calibration requires a calibrated frequency counter.
2965 Fortunately, once set, the variation in frequency due to aging and
2966 temperature changes is small enough that re-calibration by customers
2967 should generally not be required.
2970 To calibrate the radio frequency, connect the UHF antenna port to a
2971 frequency counter, set the board to 434.550MHz, and use the 'C'
2972 command in the on-board command interpreter to generate a CW
2973 carrier. For TeleMetrum, this is best done over USB. For TeleMini,
2974 note that the only way to escape the 'C' command is via power cycle
2975 since the board will no longer be listening for commands once it
2976 starts generating a CW carrier.
2979 Wait for the transmitter temperature to stabilize and the frequency
2980 to settle down. Then, divide 434.550 MHz by the
2981 measured frequency and multiply by the current radio cal value show
2982 in the 'c s' command. For an unprogrammed board, the default value
2983 is 1186611. Take the resulting integer and program it using the 'c f'
2984 command. Testing with the 'C' command again should show a carrier
2985 within a few tens of Hertz of the intended frequency.
2986 As with all 'c' sub-commands, follow this with a 'c w' to write the
2987 change to the parameter block in the on-board DataFlash chip.
2990 Note that any time you re-do the radio frequency calibration, the
2991 radio frequency is reset to the default 434.550 Mhz. If you want
2992 to use another frequency, you will have to set that again after
2993 calibration is completed.
2997 <title>TeleMetrum Accelerometer</title>
2999 The TeleMetrum accelerometer we use has its own 5 volt power
3001 the output must be passed through a resistive voltage divider to match
3002 the input of our 3.3 volt ADC. This means that unlike the barometric
3003 sensor, the output of the acceleration sensor is not ratio-metric to
3004 the ADC converter, and calibration is required. Explicitly
3005 calibrating the accelerometers also allows us to load any device
3006 from a Freescale family that includes at least +/- 40g, 50g, 100g,
3007 and 200g parts. Using gravity,
3008 a simple 2-point calibration yields acceptable results capturing both
3009 the different sensitivities and ranges of the different accelerometer
3010 parts and any variation in power supply voltages or resistor values
3011 in the divider network.
3014 To calibrate the acceleration sensor, use the 'c a 0' command. You
3015 will be prompted to orient the board vertically with the UHF antenna
3016 up and press a key, then to orient the board vertically with the
3017 UHF antenna down and press a key. Note that the accuracy of this
3018 calibration depends primarily on how perfectly vertical and still
3019 the board is held during the cal process. As with all 'c'
3020 sub-commands, follow this with a 'c w' to write the
3021 change to the parameter block in the on-board DataFlash chip.
3024 The +1g and -1g calibration points are included in each telemetry
3025 frame and are part of the header stored in onboard flash to be
3026 downloaded after flight. We always store and return raw ADC
3027 samples for each sensor... so nothing is permanently "lost" or
3028 "damaged" if the calibration is poor.
3031 In the unlikely event an accel cal goes badly, it is possible
3032 that TeleMetrum may always come up in 'pad mode' and as such not be
3033 listening to either the USB or radio link. If that happens,
3034 there is a special hook in the firmware to force the board back
3035 in to 'idle mode' so you can re-do the cal. To use this hook, you
3036 just need to ground the SPI clock pin at power-on. This pin is
3037 available as pin 2 on the 8-pin companion connector, and pin 1 is
3038 ground. So either carefully install a fine-gauge wire jumper
3039 between the two pins closest to the index hole end of the 8-pin
3040 connector, or plug in the programming cable to the 8-pin connector
3041 and use a small screwdriver or similar to short the two pins closest
3042 to the index post on the 4-pin end of the programming cable, and
3043 power up the board. It should come up in 'idle mode' (two beeps),
3049 <title>Release Notes</title>
3051 <title>Version 1.3</title>
3053 xmlns:xi="http://www.w3.org/2001/XInclude"
3054 href="release-notes-1.3.xsl"
3055 xpointer="xpointer(/article/*)"/>
3058 <title>Version 1.2.1</title>
3060 xmlns:xi="http://www.w3.org/2001/XInclude"
3061 href="release-notes-1.2.1.xsl"
3062 xpointer="xpointer(/article/*)"/>
3065 <title>Version 1.2</title>
3067 xmlns:xi="http://www.w3.org/2001/XInclude"
3068 href="release-notes-1.2.xsl"
3069 xpointer="xpointer(/article/*)"/>
3072 <title>Version 1.1.1</title>
3074 xmlns:xi="http://www.w3.org/2001/XInclude"
3075 href="release-notes-1.1.1.xsl"
3076 xpointer="xpointer(/article/*)"/>
3079 <title>Version 1.1</title>
3081 xmlns:xi="http://www.w3.org/2001/XInclude"
3082 href="release-notes-1.1.xsl"
3083 xpointer="xpointer(/article/*)"/>
3086 <title>Version 1.0.1</title>
3088 xmlns:xi="http://www.w3.org/2001/XInclude"
3089 href="release-notes-1.0.1.xsl"
3090 xpointer="xpointer(/article/*)"/>
3093 <title>Version 0.9.2</title>
3095 xmlns:xi="http://www.w3.org/2001/XInclude"
3096 href="release-notes-0.9.2.xsl"
3097 xpointer="xpointer(/article/*)"/>
3100 <title>Version 0.9</title>
3102 xmlns:xi="http://www.w3.org/2001/XInclude"
3103 href="release-notes-0.9.xsl"
3104 xpointer="xpointer(/article/*)"/>
3107 <title>Version 0.8</title>
3109 xmlns:xi="http://www.w3.org/2001/XInclude"
3110 href="release-notes-0.8.xsl"
3111 xpointer="xpointer(/article/*)"/>
3114 <title>Version 0.7.1</title>
3116 xmlns:xi="http://www.w3.org/2001/XInclude"
3117 href="release-notes-0.7.1.xsl"
3118 xpointer="xpointer(/article/*)"/>
3123 <!-- LocalWords: Altusmetrum
projects / fw / altos / blob