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5 <title>The Altus Metrum System</title>
6 <subtitle>An Owner's Manual for TeleMetrum, TeleMini and TeleDongle Devices</subtitle>
9 <firstname>Bdale</firstname>
10 <surname>Garbee</surname>
13 <firstname>Keith</firstname>
14 <surname>Packard</surname>
17 <firstname>Bob</firstname>
18 <surname>Finch</surname>
21 <firstname>Anthony</firstname>
22 <surname>Towns</surname>
26 <holder>Bdale Garbee and Keith Packard</holder>
30 This document is released under the terms of the
31 <ulink url="http://creativecommons.org/licenses/by-sa/3.0/">
32 Creative Commons ShareAlike 3.0
39 <revnumber>1.1.1</revnumber>
40 <date>16 September 2012</date>
42 Updated for software version 1.1.1 Version 1.1.1 fixes a few
43 bugs found in version 1.1.
47 <revnumber>1.1</revnumber>
48 <date>13 September 2012</date>
50 Updated for software version 1.1. Version 1.1 has new
51 features but is otherwise compatible with version 1.0.
55 <revnumber>1.0</revnumber>
56 <date>24 August 2011</date>
58 Updated for software version 1.0. Note that 1.0 represents a
59 telemetry format change, meaning both ends of a link
60 (TeleMetrum/TeleMini and TeleDongle) must be updated or
61 communications will fail.
65 <revnumber>0.9</revnumber>
66 <date>18 January 2011</date>
68 Updated for software version 0.9. Note that 0.9 represents a
69 telemetry format change, meaning both ends of a link (TeleMetrum and
70 TeleDongle) must be updated or communications will fail.
74 <revnumber>0.8</revnumber>
75 <date>24 November 2010</date>
76 <revremark>Updated for software version 0.8 </revremark>
82 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing "The
83 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
84 Kit" which formed the basis of the original Getting Started chapter
85 in this manual. Bob was one of our first customers for a production
86 TeleMetrum, and his continued enthusiasm and contributions
87 are immensely gratifying and highly appreciated!
90 And thanks to Anthony (AJ) Towns for major contributions including
91 the AltosUI graphing and site map code and associated documentation.
92 Free software means that our customers and friends can become our
93 collaborators, and we certainly appreciate this level of
97 Have fun using these products, and we hope to meet all of you
98 out on the rocket flight line somewhere.
101 NAR #87103, TRA #12201
103 Keith Packard, KD7SQG
104 NAR #88757, TRA #12200
109 <title>Introduction and Overview</title>
111 Welcome to the Altus Metrum community! Our circuits and software reflect
112 our passion for both hobby rocketry and Free Software. We hope their
113 capabilities and performance will delight you in every way, but by
114 releasing all of our hardware and software designs under open licenses,
115 we also hope to empower you to take as active a role in our collective
119 The first device created for our community was TeleMetrum, a dual
120 deploy altimeter with fully integrated GPS and radio telemetry
121 as standard features, and a "companion interface" that will
122 support optional capabilities in the future.
125 Our second device was TeleMini, a dual deploy altimeter with
126 radio telemetry and radio direction finding. This device is only
127 13mm by 38mm (½ inch by 1½ inches) and can fit easily in an 18mm
131 Complementing TeleMetrum and TeleMini is TeleDongle, a USB to RF
132 interface for communicating with the altimeters. Combined with your
133 choice of antenna and
134 notebook computer, TeleDongle and our associated user interface software
135 form a complete ground station capable of logging and displaying in-flight
136 telemetry, aiding rocket recovery, then processing and archiving flight
137 data for analysis and review.
140 More products will be added to the Altus Metrum family over time, and
141 we currently envision that this will be a single, comprehensive manual
142 for the entire product family.
146 <title>Getting Started</title>
148 The first thing to do after you check the inventory of parts in your
149 "starter kit" is to charge the battery.
152 The TeleMetrum battery can be charged by plugging it into the
153 corresponding socket of the TeleMetrum and then using the USB A to
155 cable to plug the TeleMetrum into your computer's USB socket. The
156 TeleMetrum circuitry will charge the battery whenever it is plugged
157 in, because the TeleMetrum's on-off switch does NOT control the
161 When the GPS chip is initially searching for
162 satellites, TeleMetrum will consume more current than it can pull
163 from the USB port, so the battery must be attached in order to get
164 satellite lock. Once GPS is locked, the current consumption goes back
165 down enough to enable charging while
166 running. So it's a good idea to fully charge the battery as your
167 first item of business so there is no issue getting and maintaining
168 satellite lock. The yellow charge indicator led will go out when the
169 battery is nearly full and the charger goes to trickle charge. It
170 can take several hours to fully recharge a deeply discharged battery.
173 The TeleMini battery can be charged by disconnecting it from the
174 TeleMini board and plugging it into a standalone battery charger
175 such as the LipoCharger product included in TeleMini Starter Kits,
176 and connecting that via a USB cable to a laptop or other USB
180 The other active device in the starter kit is the TeleDongle USB to
181 RF interface. If you plug it in to your Mac or Linux computer it should
182 "just work", showing up as a serial port device. Windows systems need
183 driver information that is part of the AltOS download to know that the
184 existing USB modem driver will work. We therefore recommend installing
185 our software before plugging in TeleDongle if you are using a Windows
186 computer. If you are using Linux and are having problems, try moving
187 to a fresher kernel (2.6.33 or newer), as the USB serial driver had
188 ugly bugs in some earlier versions.
191 Next you should obtain and install the AltOS software. These include
192 the AltosUI ground station program, current firmware images for
193 TeleMetrum, TeleMini and TeleDongle, and a number of standalone
194 utilities that are rarely needed. Pre-built binary packages are
195 available for Linux, Microsoft Windows, and recent MacOSX versions.
196 Full source code and build instructions are also available.
197 The latest version may always be downloaded from
198 <ulink url="http://altusmetrum.org/AltOS"/>.
202 <title>Handling Precautions</title>
204 All Altus Metrum products are sophisticated electronic devices.
205 When handled gently and properly installed in an air-frame, they
206 will deliver impressive results. However, as with all electronic
207 devices, there are some precautions you must take.
210 The Lithium Polymer rechargeable batteries have an
211 extraordinary power density. This is great because we can fly with
212 much less battery mass than if we used alkaline batteries or previous
213 generation rechargeable batteries... but if they are punctured
214 or their leads are allowed to short, they can and will release their
216 Thus we recommend that you take some care when handling our batteries
217 and consider giving them some extra protection in your air-frame. We
218 often wrap them in suitable scraps of closed-cell packing foam before
219 strapping them down, for example.
222 The barometric sensors used on both TeleMetrum and TeleMini are
223 sensitive to sunlight. In normal TeleMetrum mounting situations, it
224 and all of the other surface mount components
225 are "down" towards whatever the underlying mounting surface is, so
226 this is not normally a problem. Please consider this, though, when
227 designing an installation, for example, in an air-frame with a
228 see-through plastic payload bay. It is particularly important to
229 consider this with TeleMini, both because the baro sensor is on the
230 "top" of the board, and because many model rockets with payload bays
231 use clear plastic for the payload bay! Replacing these with an opaque
232 cardboard tube, painting them, or wrapping them with a layer of masking
233 tape are all reasonable approaches to keep the sensor out of direct
237 The barometric sensor sampling port must be able to "breathe",
238 both by not being covered by foam or tape or other materials that might
239 directly block the hole on the top of the sensor, and also by having a
240 suitable static vent to outside air.
243 As with all other rocketry electronics, Altus Metrum altimeters must
244 be protected from exposure to corrosive motor exhaust and ejection
249 <title>Hardware Overview</title>
251 TeleMetrum is a 1 inch by 2.75 inch circuit board. It was designed to
252 fit inside coupler for 29mm air-frame tubing, but using it in a tube that
253 small in diameter may require some creativity in mounting and wiring
254 to succeed! The presence of an accelerometer means TeleMetrum should
255 be aligned along the flight axis of the airframe, and by default the 1/4
256 wave UHF wire antenna should be on the nose-cone end of the board. The
257 antenna wire is about 7 inches long, and wiring for a power switch and
258 the e-matches for apogee and main ejection charges depart from the
259 fin can end of the board, meaning an ideal "simple" avionics
260 bay for TeleMetrum should have at least 10 inches of interior length.
263 TeleMini is a 0.5 inch by 1.5 inch circuit board. It was designed to
264 fit inside an 18mm air-frame tube, but using it in a tube that
265 small in diameter may require some creativity in mounting and wiring
266 to succeed! Since there is no accelerometer, TeleMini can be mounted
267 in any convenient orientation. The default 1/4
268 wave UHF wire antenna attached to the center of one end of
269 the board is about 7 inches long, and wiring for a power switch and
270 the e-matches for apogee and main ejection charges depart from the
271 other end of the board, meaning an ideal "simple" avionics
272 bay for TeleMini should have at least 9 inches of interior length.
275 A typical TeleMetrum or TeleMini installation involves attaching
276 only a suitable Lithium Polymer battery, a single pole switch for
277 power on/off, and two pairs of wires connecting e-matches for the
278 apogee and main ejection charges. All Altus Metrum products are
279 designed for use with single-cell batteries with 3.7 volts nominal.
282 The battery connectors are a standard 2-pin JST connector and
283 match batteries sold by Spark Fun. These batteries are
284 single-cell Lithium Polymer batteries that nominally provide 3.7
285 volts. Other vendors sell similar batteries for RC aircraft
286 using mating connectors, however the polarity for those is
287 generally reversed from the batteries used by Altus Metrum
288 products. In particular, the Tenergy batteries supplied for use
289 in Featherweight flight computers are not compatible with Altus
290 Metrum flight computers or battery chargers. <emphasis>Check
291 polarity and voltage before connecting any battery not purchased
292 from Altus Metrum or Spark Fun.</emphasis>
295 By default, we use the unregulated output of the Li-Po battery directly
296 to fire ejection charges. This works marvelously with standard
297 low-current e-matches like the J-Tek from MJG Technologies, and with
298 Quest Q2G2 igniters. However, if you want or need to use a separate
299 pyro battery, check out the "External Pyro Battery" section in this
300 manual for instructions on how to wire that up. The altimeters are
301 designed to work with an external pyro battery of no more than 15 volts.
304 Ejection charges are wired directly to the screw terminal block
305 at the aft end of the altimeter. You'll need a very small straight
306 blade screwdriver for these screws, such as you might find in a
307 jeweler's screwdriver set.
310 TeleMetrum also uses the screw terminal block for the power
311 switch leads. On TeleMini, the power switch leads are soldered
312 directly to the board and can be connected directly to a switch.
315 For most air-frames, the integrated antennas are more than
316 adequate. However, if you are installing in a carbon-fiber or
317 metal electronics bay which is opaque to RF signals, you may need to
318 use off-board external antennas instead. In this case, you can
319 order an altimeter with an SMA connector for the UHF antenna
320 connection, and, on TeleMetrum, you can unplug the integrated GPS
321 antenna and select an appropriate off-board GPS antenna with
322 cable terminating in a U.FL connector.
326 <title>System Operation</title>
328 <title>Firmware Modes </title>
330 The AltOS firmware build for the altimeters has two
331 fundamental modes, "idle" and "flight". Which of these modes
332 the firmware operates in is determined at start up time. For
333 TeleMetrum, the mode is controlled by the orientation of the
334 rocket (well, actually the board, of course...) at the time
335 power is switched on. If the rocket is "nose up", then
336 TeleMetrum assumes it's on a rail or rod being prepared for
337 launch, so the firmware chooses flight mode. However, if the
338 rocket is more or less horizontal, the firmware instead enters
339 idle mode. Since TeleMini doesn't have an accelerometer we can
340 use to determine orientation, "idle" mode is selected when the
341 board receives a command packet within the first five seconds
342 of operation; if no packet is received, the board enters
346 At power on, you will hear three beeps or see three flashes
347 ("S" in Morse code for start up) and then a pause while
348 the altimeter completes initialization and self test, and decides
349 which mode to enter next.
352 In flight or "pad" mode, the altimeter engages the flight
353 state machine, goes into transmit-only mode to
354 send telemetry, and waits for launch to be detected.
355 Flight mode is indicated by an "di-dah-dah-dit" ("P" for pad)
356 on the beeper or lights, followed by beeps or flashes
357 indicating the state of the pyrotechnic igniter continuity.
358 One beep/flash indicates apogee continuity, two beeps/flashes
359 indicate main continuity, three beeps/flashes indicate both
360 apogee and main continuity, and one longer "brap" sound or
361 rapidly alternating lights indicates no continuity. For a
362 dual deploy flight, make sure you're getting three beeps or
363 flashes before launching! For apogee-only or motor eject
364 flights, do what makes sense.
367 If idle mode is entered, you will hear an audible "di-dit" or see
368 two short flashes ("I" for idle), and the flight state machine is
369 disengaged, thus no ejection charges will fire. The altimeters also
370 listen for the radio link when in idle mode for requests sent via
371 TeleDongle. Commands can be issued to a TeleMetrum in idle mode
373 USB or the radio link equivalently. TeleMini only has the radio link.
374 Idle mode is useful for configuring the altimeter, for extracting data
375 from the on-board storage chip after flight, and for ground testing
379 One "neat trick" of particular value when TeleMetrum is used with
380 very large air-frames, is that you can power the board up while the
381 rocket is horizontal, such that it comes up in idle mode. Then you can
382 raise the air-frame to launch position, and issue a 'reset' command
383 via TeleDongle over the radio link to cause the altimeter to reboot and
384 come up in flight mode. This is much safer than standing on the top
385 step of a rickety step-ladder or hanging off the side of a launch
386 tower with a screw-driver trying to turn on your avionics before
393 TeleMetrum includes a complete GPS receiver. A complete explanation
394 of how GPS works is beyond the scope of this manual, but the bottom
395 line is that the TeleMetrum GPS receiver needs to lock onto at least
396 four satellites to obtain a solid 3 dimensional position fix and know
400 TeleMetrum provides backup power to the GPS chip any time a
401 battery is connected. This allows the receiver to "warm start" on
402 the launch rail much faster than if every power-on were a GPS
403 "cold start". In typical operations, powering up TeleMetrum
404 on the flight line in idle mode while performing final air-frame
405 preparation will be sufficient to allow the GPS receiver to cold
406 start and acquire lock. Then the board can be powered down during
407 RSO review and installation on a launch rod or rail. When the board
408 is turned back on, the GPS system should lock very quickly, typically
409 long before igniter installation and return to the flight line are
414 <title>Controlling An Altimeter Over The Radio Link</title>
416 One of the unique features of the Altus Metrum system is
417 the ability to create a two way command link between TeleDongle
418 and an altimeter using the digital radio transceivers built into
419 each device. This allows you to interact with the altimeter from
420 afar, as if it were directly connected to the computer.
423 Any operation which can be performed with TeleMetrum can
424 either be done with TeleMetrum directly connected to the
425 computer via the USB cable, or through the radio
426 link. TeleMini doesn't provide a USB connector and so it is
427 always communicated with over radio. Select the appropriate
428 TeleDongle device when the list of devices is presented and
429 AltosUI will interact with an altimeter over the radio link.
432 One oddity in the current interface is how AltosUI selects the
433 frequency for radio communications. Instead of providing
434 an interface to specifically configure the frequency, it uses
435 whatever frequency was most recently selected for the target
436 TeleDongle device in Monitor Flight mode. If you haven't ever
437 used that mode with the TeleDongle in question, select the
438 Monitor Flight button from the top level UI, and pick the
439 appropriate TeleDongle device. Once the flight monitoring
440 window is open, select the desired frequency and then close it
441 down again. All radio communications will now use that frequency.
446 Save Flight Data—Recover flight data from the rocket without
452 Configure altimeter apogee delays or main deploy heights
453 to respond to changing launch conditions. You can also
454 'reboot' the altimeter. Use this to remotely enable the
455 flight computer by turning TeleMetrum on in "idle" mode,
456 then once the air-frame is oriented for launch, you can
457 reboot the altimeter and have it restart in pad mode
458 without having to climb the scary ladder.
463 Fire Igniters—Test your deployment charges without snaking
464 wires out through holes in the air-frame. Simply assembly the
465 rocket as if for flight with the apogee and main charges
466 loaded, then remotely command the altimeter to fire the
472 Operation over the radio link for configuring an altimeter, ground
473 testing igniters, and so forth uses the same RF frequencies as flight
474 telemetry. To configure the desired TeleDongle frequency, select
475 the monitor flight tab, then use the frequency selector and
476 close the window before performing other desired radio operations.
479 TeleMetrum only enables radio commanding in 'idle' mode, so
480 make sure you have TeleMetrum lying horizontally when you turn
481 it on. Otherwise, TeleMetrum will start in 'pad' mode ready for
482 flight, and will not be listening for command packets from TeleDongle.
485 TeleMini listens for a command packet for five seconds after
486 first being turned on, if it doesn't hear anything, it enters
487 'pad' mode, ready for flight and will no longer listen for
488 command packets. The easiest way to connect to TeleMini is to
489 initiate the command and select the TeleDongle device. At this
490 point, the TeleDongle will be attempting to communicate with
491 the TeleMini. Now turn TeleMini on, and it should immediately
492 start communicating with the TeleDongle and the desired
493 operation can be performed.
496 You can monitor the operation of the radio link by watching the
497 lights on the devices. The red LED will flash each time a packet
498 is transmitted, while the green LED will light up on TeleDongle when
499 it is waiting to receive a packet from the altimeter.
503 <title>Ground Testing </title>
505 An important aspect of preparing a rocket using electronic deployment
506 for flight is ground testing the recovery system. Thanks
507 to the bi-directional radio link central to the Altus Metrum system,
508 this can be accomplished in a TeleMetrum or TeleMini equipped rocket
509 with less work than you may be accustomed to with other systems. It
513 Just prep the rocket for flight, then power up the altimeter
514 in "idle" mode (placing air-frame horizontal for TeleMetrum or
515 selected the Configure Altimeter tab for TeleMini). This will cause
516 the firmware to go into "idle" mode, in which the normal flight
517 state machine is disabled and charges will not fire without
518 manual command. You can now command the altimeter to fire the apogee
519 or main charges from a safe distance using your computer and
520 TeleDongle and the Fire Igniter tab to complete ejection testing.
524 <title>Radio Link </title>
526 The chip our boards are based on incorporates an RF transceiver, but
527 it's not a full duplex system... each end can only be transmitting or
528 receiving at any given moment. So we had to decide how to manage the
532 By design, the altimeter firmware listens for the radio link when
533 it's in "idle mode", which
534 allows us to use the radio link to configure the rocket, do things like
535 ejection tests, and extract data after a flight without having to
536 crack open the air-frame. However, when the board is in "flight
537 mode", the altimeter only
538 transmits and doesn't listen at all. That's because we want to put
539 ultimate priority on event detection and getting telemetry out of
541 the radio in case the rocket crashes and we aren't able to extract
545 We don't use a 'normal packet radio' mode like APRS because they're
546 just too inefficient. The GFSK modulation we use is FSK with the
547 base-band pulses passed through a
548 Gaussian filter before they go into the modulator to limit the
549 transmitted bandwidth. When combined with the hardware forward error
550 correction support in the cc1111 chip, this allows us to have a very
551 robust 38.4 kilobit data link with only 10 milliwatts of transmit
552 power, a whip antenna in the rocket, and a hand-held Yagi on the
553 ground. We've had flights to above 21k feet AGL with great reception,
554 and calculations suggest we should be good to well over 40k feet AGL
555 with a 5-element yagi on the ground. We hope to fly boards to higher
556 altitudes over time, and would of course appreciate customer feedback
557 on performance in higher altitude flights!
561 <title>Configurable Parameters</title>
563 Configuring an Altus Metrum altimeter for flight is very
564 simple. Even on our baro-only TeleMini board, the use of a Kalman
565 filter means there is no need to set a "mach delay". The few
566 configurable parameters can all be set using AltosUI over USB or
567 or radio link via TeleDongle.
570 <title>Radio Frequency</title>
572 Altus Metrum boards support radio frequencies in the 70cm
573 band. By default, the configuration interface provides a
574 list of 10 "standard" frequencies in 100kHz channels starting at
575 434.550MHz. However, the firmware supports use of
576 any 50kHz multiple within the 70cm band. At any given
577 launch, we highly recommend coordinating when and by whom each
578 frequency will be used to avoid interference. And of course, both
579 altimeter and TeleDongle must be configured to the same
580 frequency to successfully communicate with each other.
584 <title>Apogee Delay</title>
586 Apogee delay is the number of seconds after the altimeter detects flight
587 apogee that the drogue charge should be fired. In most cases, this
588 should be left at the default of 0. However, if you are flying
589 redundant electronics such as for an L3 certification, you may wish
590 to set one of your altimeters to a positive delay so that both
591 primary and backup pyrotechnic charges do not fire simultaneously.
594 The Altus Metrum apogee detection algorithm fires exactly at
595 apogee. If you are also flying an altimeter like the
596 PerfectFlite MAWD, which only supports selecting 0 or 1
597 seconds of apogee delay, you may wish to set the MAWD to 0
598 seconds delay and set the TeleMetrum to fire your backup 2
599 or 3 seconds later to avoid any chance of both charges
600 firing simultaneously. We've flown several air-frames this
601 way quite happily, including Keith's successful L3 cert.
605 <title>Main Deployment Altitude</title>
607 By default, the altimeter will fire the main deployment charge at an
608 elevation of 250 meters (about 820 feet) above ground. We think this
609 is a good elevation for most air-frames, but feel free to change this
610 to suit. In particular, if you are flying two altimeters, you may
612 deployment elevation for the backup altimeter to be something lower
613 than the primary so that both pyrotechnic charges don't fire
618 <title>Maximum Flight Log</title>
620 TeleMetrum version 1.1 and 1.2 have 2MB of on-board flash storage,
621 enough to hold over 40 minutes of data at full data rate
622 (100 samples/second). TeleMetrum 1.0 has 1MB of on-board
623 storage. As data are stored at a reduced rate during descent
624 (10 samples/second), there's plenty of space to store many
625 flights worth of data.
628 The on-board flash is partitioned into separate flight logs,
629 each of a fixed maximum size. Increase the maximum size of
630 each log and you reduce the number of flights that can be
631 stored. Decrease the size and TeleMetrum can store more
635 All of the configuration data is also stored in the flash
636 memory, which consumes 64kB on TeleMetrum v1.1/v1.2 and 256B on
637 TeleMetrum v1.0. This configuration space is not available
638 for storing flight log data.
641 To compute the amount of space needed for a single flight,
642 you can multiply the expected ascent time (in seconds) by
643 800, multiply the expected descent time (in seconds) by 80
644 and add the two together. That will slightly under-estimate
645 the storage (in bytes) needed for the flight. For instance,
646 a flight spending 20 seconds in ascent and 150 seconds in
647 descent will take about (20 * 800) + (150 * 80) = 28000
648 bytes of storage. You could store dozens of these flights in
652 The default size, 192kB, allows for 10 flights of storage on
653 TeleMetrum v1.1/v1.2 and 5 flights on TeleMetrum v1.0. This
654 ensures that you won't need to erase the memory before
655 flying each time while still allowing more than sufficient
656 storage for each flight.
659 As TeleMini does not contain an accelerometer, it stores
660 data at 10 samples per second during ascent and one sample
661 per second during descent. Each sample is a two byte reading
662 from the barometer. These are stored in 5kB of
663 on-chip flash memory which can hold 256 seconds at the
664 ascent rate or 2560 seconds at the descent rate. Because of
665 the limited storage, TeleMini cannot hold data for more than
666 one flight, and so must be erased after each flight or it
667 will not capture data for subsequent flights.
671 <title>Ignite Mode</title>
673 Instead of firing one charge at apogee and another charge at
674 a fixed height above the ground, you can configure the
675 altimeter to fire both at apogee or both during
676 descent. This was added to support an airframe that has two
677 TeleMetrum computers, one in the fin can and one in the
681 Providing the ability to use both igniters for apogee or
682 main allows some level of redundancy without needing two
683 flight computers. In Redundant Apogee or Redundant Main
684 mode, the two charges will be fired two seconds apart.
688 <title>Pad Orientation</title>
690 TeleMetrum measures acceleration along the axis of the
691 board. Which way the board is oriented affects the sign of
692 the acceleration value. Instead of trying to guess which way
693 the board is mounted in the air frame, TeleMetrum must be
694 explicitly configured for either Antenna Up or Antenna
695 Down. The default, Antenna Up, expects the end of the
696 TeleMetrum board connected to the 70cm antenna to be nearest
697 the nose of the rocket, with the end containing the screw
698 terminals nearest the tail.
706 <title>AltosUI</title>
708 The AltosUI program provides a graphical user interface for
709 interacting with the Altus Metrum product family, including
710 TeleMetrum, TeleMini and TeleDongle. AltosUI can monitor telemetry data,
711 configure TeleMetrum, TeleMini and TeleDongle devices and many other
712 tasks. The primary interface window provides a selection of
713 buttons, one for each major activity in the system. This manual
714 is split into chapters, each of which documents one of the tasks
715 provided from the top-level toolbar.
718 <title>Monitor Flight</title>
719 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
721 Selecting this item brings up a dialog box listing all of the
722 connected TeleDongle devices. When you choose one of these,
723 AltosUI will create a window to display telemetry data as
724 received by the selected TeleDongle device.
727 All telemetry data received are automatically recorded in
728 suitable log files. The name of the files includes the current
729 date and rocket serial and flight numbers.
732 The radio frequency being monitored by the TeleDongle device is
733 displayed at the top of the window. You can configure the
734 frequency by clicking on the frequency box and selecting the desired
735 frequency. AltosUI remembers the last frequency selected for each
736 TeleDongle and selects that automatically the next time you use
740 Below the TeleDongle frequency selector, the window contains a few
741 significant pieces of information about the altimeter providing
742 the telemetry data stream:
746 <para>The configured call-sign</para>
749 <para>The device serial number</para>
752 <para>The flight number. Each altimeter remembers how many
758 The rocket flight state. Each flight passes through several
759 states including Pad, Boost, Fast, Coast, Drogue, Main and
765 The Received Signal Strength Indicator value. This lets
766 you know how strong a signal TeleDongle is receiving. The
767 radio inside TeleDongle operates down to about -99dBm;
768 weaker signals may not be receivable. The packet link uses
769 error detection and correction techniques which prevent
770 incorrect data from being reported.
775 The age of the displayed data, in seconds since the last
776 successfully received telemetry packet. In normal operation
777 this will stay in the low single digits. If the number starts
778 counting up, then you are no longer receiving data over the radio
779 link from the flight computer.
784 Finally, the largest portion of the window contains a set of
785 tabs, each of which contain some information about the rocket.
786 They're arranged in 'flight order' so that as the flight
787 progresses, the selected tab automatically switches to display
788 data relevant to the current state of the flight. You can select
789 other tabs at any time. The final 'table' tab displays all of
790 the raw telemetry values in one place in a spreadsheet-like format.
793 <title>Launch Pad</title>
795 The 'Launch Pad' tab shows information used to decide when the
796 rocket is ready for flight. The first elements include red/green
797 indicators, if any of these is red, you'll want to evaluate
798 whether the rocket is ready to launch:
802 Battery Voltage. This indicates whether the Li-Po battery
803 powering the TeleMetrum has sufficient charge to last for
804 the duration of the flight. A value of more than
805 3.7V is required for a 'GO' status.
810 Apogee Igniter Voltage. This indicates whether the apogee
811 igniter has continuity. If the igniter has a low
812 resistance, then the voltage measured here will be close
813 to the Li-Po battery voltage. A value greater than 3.2V is
814 required for a 'GO' status.
819 Main Igniter Voltage. This indicates whether the main
820 igniter has continuity. If the igniter has a low
821 resistance, then the voltage measured here will be close
822 to the Li-Po battery voltage. A value greater than 3.2V is
823 required for a 'GO' status.
828 On-board Data Logging. This indicates whether there is
829 space remaining on-board to store flight data for the
830 upcoming flight. If you've downloaded data, but failed
831 to erase flights, there may not be any space
832 left. TeleMetrum can store multiple flights, depending
833 on the configured maximum flight log size. TeleMini
834 stores only a single flight, so it will need to be
835 downloaded and erased after each flight to capture
836 data. This only affects on-board flight logging; the
837 altimeter will still transmit telemetry and fire
838 ejection charges at the proper times.
843 GPS Locked. For a TeleMetrum device, this indicates whether the GPS receiver is
844 currently able to compute position information. GPS requires
845 at least 4 satellites to compute an accurate position.
850 GPS Ready. For a TeleMetrum device, this indicates whether GPS has reported at least
851 10 consecutive positions without losing lock. This ensures
852 that the GPS receiver has reliable reception from the
858 The Launchpad tab also shows the computed launch pad position
859 and altitude, averaging many reported positions to improve the
865 <title>Ascent</title>
867 This tab is shown during Boost, Fast and Coast
868 phases. The information displayed here helps monitor the
869 rocket as it heads towards apogee.
872 The height, speed and acceleration are shown along with the
873 maximum values for each of them. This allows you to quickly
874 answer the most commonly asked questions you'll hear during
878 The current latitude and longitude reported by the TeleMetrum GPS are
879 also shown. Note that under high acceleration, these values
880 may not get updated as the GPS receiver loses position
881 fix. Once the rocket starts coasting, the receiver should
882 start reporting position again.
885 Finally, the current igniter voltages are reported as in the
886 Launch Pad tab. This can help diagnose deployment failures
887 caused by wiring which comes loose under high acceleration.
891 <title>Descent</title>
893 Once the rocket has reached apogee and (we hope) activated the
894 apogee charge, attention switches to tracking the rocket on
895 the way back to the ground, and for dual-deploy flights,
896 waiting for the main charge to fire.
899 To monitor whether the apogee charge operated correctly, the
900 current descent rate is reported along with the current
901 height. Good descent rates vary based on the choice of recovery
902 components, but generally range from 15-30m/s on drogue and should
903 be below 10m/s when under the main parachute in a dual-deploy flight.
906 For TeleMetrum altimeters, you can locate the rocket in the
907 sky using the elevation and bearing information to figure
908 out where to look. Elevation is in degrees above the
909 horizon. Bearing is reported in degrees relative to true
910 north. Range can help figure out how big the rocket will
911 appear. Ground Distance shows how far it is to a point
912 directly under the rocket and can help figure out where the
913 rocket is likely to land. Note that all of these values are
914 relative to the pad location. If the elevation is near 90°,
915 the rocket is over the pad, not over you.
918 Finally, the igniter voltages are reported in this tab as
919 well, both to monitor the main charge as well as to see what
920 the status of the apogee charge is. Note that some commercial
921 e-matches are designed to retain continuity even after being
922 fired, and will continue to show as green or return from red to
927 <title>Landed</title>
929 Once the rocket is on the ground, attention switches to
930 recovery. While the radio signal is often lost once the
931 rocket is on the ground, the last reported GPS position is
932 generally within a short distance of the actual landing location.
935 The last reported GPS position is reported both by
936 latitude and longitude as well as a bearing and distance from
937 the launch pad. The distance should give you a good idea of
938 whether to walk or hitch a ride. Take the reported
939 latitude and longitude and enter them into your hand-held GPS
940 unit and have that compute a track to the landing location.
943 Both TeleMini and TeleMetrum will continue to transmit RDF
944 tones after landing, allowing you to locate the rocket by
945 following the radio signal if necessary. You may need to get
946 away from the clutter of the flight line, or even get up on
947 a hill (or your neighbor's RV roof) to receive the RDF signal.
950 The maximum height, speed and acceleration reported
951 during the flight are displayed for your admiring observers.
952 The accuracy of these immediate values depends on the quality
953 of your radio link and how many packets were received.
954 Recovering the on-board data after flight will likely yield
955 more precise results.
958 To get more detailed information about the flight, you can
959 click on the 'Graph Flight' button which will bring up a
960 graph window for the current flight.
964 <title>Site Map</title>
966 When the TeleMetrum has a GPS fix, the Site Map tab will map
967 the rocket's position to make it easier for you to locate the
968 rocket, both while it is in the air, and when it has landed. The
969 rocket's state is indicated by color: white for pad, red for
970 boost, pink for fast, yellow for coast, light blue for drogue,
971 dark blue for main, and black for landed.
974 The map's scale is approximately 3m (10ft) per pixel. The map
975 can be dragged using the left mouse button. The map will attempt
976 to keep the rocket roughly centered while data is being received.
979 Images are fetched automatically via the Google Maps Static API,
980 and cached on disk for reuse. If map images cannot be downloaded,
981 the rocket's path will be traced on a dark gray background
985 You can pre-load images for your favorite launch sites
986 before you leave home; check out the 'Preload Maps' section below.
991 <title>Save Flight Data</title>
993 The altimeter records flight data to its internal flash memory.
994 TeleMetrum data is recorded at a much higher rate than the telemetry
995 system can handle, and is not subject to radio drop-outs. As
996 such, it provides a more complete and precise record of the
997 flight. The 'Save Flight Data' button allows you to read the
998 flash memory and write it to disk. As TeleMini has only a barometer, it
999 records data at the same rate as the telemetry signal, but there will be
1000 no data lost due to telemetry drop-outs.
1003 Clicking on the 'Save Flight Data' button brings up a list of
1004 connected TeleMetrum and TeleDongle devices. If you select a
1005 TeleMetrum device, the flight data will be downloaded from that
1006 device directly. If you select a TeleDongle device, flight data
1007 will be downloaded from an altimeter over radio link via the
1008 specified TeleDongle. See the chapter on Controlling An Altimeter
1009 Over The Radio Link for more information.
1012 After the device has been selected, a dialog showing the
1013 flight data saved in the device will be shown allowing you to
1014 select which flights to download and which to delete. With
1015 version 0.9 or newer firmware, you must erase flights in order
1016 for the space they consume to be reused by another
1017 flight. This prevents accidentally losing flight data
1018 if you neglect to download data before flying again. Note that
1019 if there is no more space available in the device, then no
1020 data will be recorded during the next flight.
1023 The file name for each flight log is computed automatically
1024 from the recorded flight date, altimeter serial number and
1025 flight number information.
1029 <title>Replay Flight</title>
1031 Select this button and you are prompted to select a flight
1032 record file, either a .telem file recording telemetry data or a
1033 .eeprom file containing flight data saved from the altimeter
1037 Once a flight record is selected, the flight monitor interface
1038 is displayed and the flight is re-enacted in real time. Check
1039 the Monitor Flight chapter above to learn how this window operates.
1043 <title>Graph Data</title>
1045 Select this button and you are prompted to select a flight
1046 record file, either a .telem file recording telemetry data or a
1047 .eeprom file containing flight data saved from
1051 Once a flight record is selected, a window with two tabs is
1052 opened. The first tab contains a graph with acceleration
1053 (blue), velocity (green) and altitude (red) of the flight,
1054 measured in metric units. The
1055 apogee(yellow) and main(magenta) igniter voltages are also
1056 displayed; high voltages indicate continuity, low voltages
1057 indicate open circuits. The second tab contains some basic
1061 The graph can be zoomed into a particular area by clicking and
1062 dragging down and to the right. Once zoomed, the graph can be
1063 reset by clicking and dragging up and to the left. Holding down
1064 control and clicking and dragging allows the graph to be panned.
1065 The right mouse button causes a pop-up menu to be displayed, giving
1066 you the option save or print the plot.
1069 Note that telemetry files will generally produce poor graphs
1070 due to the lower sampling rate and missed telemetry packets.
1071 Use saved flight data in .eeprom files for graphing where possible.
1075 <title>Export Data</title>
1077 This tool takes the raw data files and makes them available for
1078 external analysis. When you select this button, you are prompted to
1080 data file (either .eeprom or .telem will do, remember that
1081 .eeprom files contain higher resolution and more continuous
1082 data). Next, a second dialog appears which is used to select
1083 where to write the resulting file. It has a selector to choose
1084 between CSV and KML file formats.
1087 <title>Comma Separated Value Format</title>
1089 This is a text file containing the data in a form suitable for
1090 import into a spreadsheet or other external data analysis
1091 tool. The first few lines of the file contain the version and
1092 configuration information from the altimeter, then
1093 there is a single header line which labels all of the
1094 fields. All of these lines start with a '#' character which
1095 many tools can be configured to skip over.
1098 The remaining lines of the file contain the data, with each
1099 field separated by a comma and at least one space. All of
1100 the sensor values are converted to standard units, with the
1101 barometric data reported in both pressure, altitude and
1102 height above pad units.
1106 <title>Keyhole Markup Language (for Google Earth)</title>
1108 This is the format used by Google Earth to provide an overlay
1109 within that application. With this, you can use Google Earth to
1110 see the whole flight path in 3D.
1115 <title>Configure Altimeter</title>
1117 Select this button and then select either a TeleMetrum or
1118 TeleDongle Device from the list provided. Selecting a TeleDongle
1119 device will use the radio link to configure a remote altimeter.
1122 The first few lines of the dialog provide information about the
1123 connected device, including the product name,
1124 software version and hardware serial number. Below that are the
1125 individual configuration entries.
1128 At the bottom of the dialog, there are four buttons:
1133 Save. This writes any changes to the
1134 configuration parameter block in flash memory. If you don't
1135 press this button, any changes you make will be lost.
1140 Reset. This resets the dialog to the most recently saved values,
1141 erasing any changes you have made.
1146 Reboot. This reboots the device. Use this to
1147 switch from idle to pad mode by rebooting once the rocket is
1148 oriented for flight, or to confirm changes you think you saved
1154 Close. This closes the dialog. Any unsaved changes will be
1160 The rest of the dialog contains the parameters to be configured.
1163 <title>Main Deploy Altitude</title>
1165 This sets the altitude (above the recorded pad altitude) at
1166 which the 'main' igniter will fire. The drop-down menu shows
1167 some common values, but you can edit the text directly and
1168 choose whatever you like. If the apogee charge fires below
1169 this altitude, then the main charge will fire two seconds
1170 after the apogee charge fires.
1174 <title>Apogee Delay</title>
1176 When flying redundant electronics, it's often important to
1177 ensure that multiple apogee charges don't fire at precisely
1178 the same time, as that can over pressurize the apogee deployment
1179 bay and cause a structural failure of the air-frame. The Apogee
1180 Delay parameter tells the flight computer to fire the apogee
1181 charge a certain number of seconds after apogee has been
1186 <title>Radio Frequency</title>
1188 This configures which of the configured frequencies to use for both
1189 telemetry and packet command mode. Note that if you set this
1190 value via packet command mode, you will have to reconfigure
1191 the TeleDongle frequency before you will be able to use packet
1196 <title>Radio Calibration</title>
1198 The radios in every Altus Metrum device are calibrated at the
1199 factory to ensure that they transmit and receive on the
1200 specified frequency. If you need to you can adjust the calibration
1201 by changing this value. Do not do this without understanding what
1202 the value means, read the appendix on calibration and/or the source
1203 code for more information. To change a TeleDongle's calibration,
1204 you must reprogram the unit completely.
1208 <title>Callsign</title>
1210 This sets the call sign included in each telemetry packet. Set this
1211 as needed to conform to your local radio regulations.
1215 <title>Maximum Flight Log Size</title>
1217 This sets the space (in kilobytes) allocated for each flight
1218 log. The available space will be divided into chunks of this
1219 size. A smaller value will allow more flights to be stored,
1220 a larger value will record data from longer flights.
1224 <title>Ignite Mode</title>
1226 TeleMetrum and TeleMini provide two igniter channels as they
1227 were originally designed as dual-deploy flight
1228 computers. This configuration parameter allows the two
1229 channels to be used in different configurations.
1234 Dual Deploy. This is the usual mode of operation; the
1235 'apogee' channel is fired at apogee and the 'main'
1236 channel at the height above ground specified by the
1237 'Main Deploy Altitude' during descent.
1242 Redundant Apogee. This fires both channels at
1243 apogee, the 'apogee' channel first followed after a two second
1244 delay by the 'main' channel.
1249 Redundant Main. This fires both channels at the
1250 height above ground specified by the Main Deploy
1251 Altitude setting during descent. The 'apogee'
1252 channel is fired first, followed after a two second
1253 delay by the 'main' channel.
1259 <title>Pad Orientation</title>
1261 Because it includes an accelerometer, TeleMetrum is
1262 sensitive to the orientation of the board. By default, it
1263 expects the antenna end to point forward. This parameter
1264 allows that default to be changed, permitting the board to
1265 be mounted with the antenna pointing aft instead.
1270 Antenna Up. In this mode, the antenna end of the
1271 TeleMetrum board must point forward, in line with the
1272 expected flight path.
1277 Antenna Down. In this mode, the antenna end of the
1278 TeleMetrum board must point aft, in line with the
1279 expected flight path.
1286 <title>Configure AltosUI</title>
1288 This button presents a dialog so that you can configure the AltosUI global settings.
1291 <title>Voice Settings</title>
1293 AltosUI provides voice announcements during flight so that you
1294 can keep your eyes on the sky and still get information about
1295 the current flight status. However, sometimes you don't want
1300 <para>Enable—turns all voice announcements on and off</para>
1304 Test Voice—Plays a short message allowing you to verify
1305 that the audio system is working and the volume settings
1312 <title>Log Directory</title>
1314 AltosUI logs all telemetry data and saves all TeleMetrum flash
1315 data to this directory. This directory is also used as the
1316 staring point when selecting data files for display or export.
1319 Click on the directory name to bring up a directory choosing
1320 dialog, select a new directory and click 'Select Directory' to
1321 change where AltosUI reads and writes data files.
1325 <title>Callsign</title>
1327 This value is transmitted in each command packet sent from
1328 TeleDongle and received from an altimeter. It is not used in
1329 telemetry mode, as the callsign configured in the altimeter board
1330 is included in all telemetry packets. Configure this
1331 with the AltosUI operators call sign as needed to comply with
1332 your local radio regulations.
1336 <title>Imperial Units</title>
1338 This switches between metric units (meters) and imperial
1339 units (feet and miles). This affects the display of values
1340 use during flight monitoring, data graphing and all of the
1341 voice announcements. It does not change the units used when
1342 exporting to CSV files, those are always produced in metric units.
1346 <title>Font Size</title>
1348 Selects the set of fonts used in the flight monitor
1349 window. Choose between the small, medium and large sets.
1353 <title>Serial Debug</title>
1355 This causes all communication with a connected device to be
1356 dumped to the console from which AltosUI was started. If
1357 you've started it from an icon or menu entry, the output
1358 will simply be discarded. This mode can be useful to debug
1359 various serial communication issues.
1363 <title>Manage Frequencies</title>
1365 This brings up a dialog where you can configure the set of
1366 frequencies shown in the various frequency menus. You can
1367 add as many as you like, or even reconfigure the default
1368 set. Changing this list does not affect the frequency
1369 settings of any devices, it only changes the set of
1370 frequencies shown in the menus.
1375 <title>Configure Groundstation</title>
1377 Select this button and then select a TeleDongle Device from the list provided.
1380 The first few lines of the dialog provide information about the
1381 connected device, including the product name,
1382 software version and hardware serial number. Below that are the
1383 individual configuration entries.
1386 Note that the TeleDongle itself doesn't save any configuration
1387 data, the settings here are recorded on the local machine in
1388 the Java preferences database. Moving the TeleDongle to
1389 another machine, or using a different user account on the same
1390 machine will cause settings made here to have no effect.
1393 At the bottom of the dialog, there are three buttons:
1398 Save. This writes any changes to the
1399 local Java preferences file. If you don't
1400 press this button, any changes you make will be lost.
1405 Reset. This resets the dialog to the most recently saved values,
1406 erasing any changes you have made.
1411 Close. This closes the dialog. Any unsaved changes will be
1417 The rest of the dialog contains the parameters to be configured.
1420 <title>Frequency</title>
1422 This configures the frequency to use for both telemetry and
1423 packet command mode. Set this before starting any operation
1424 involving packet command mode so that it will use the right
1425 frequency. Telemetry monitoring mode also provides a menu to
1426 change the frequency, and that menu also sets the same Java
1427 preference value used here.
1431 <title>Radio Calibration</title>
1433 The radios in every Altus Metrum device are calibrated at the
1434 factory to ensure that they transmit and receive on the
1435 specified frequency. To change a TeleDongle's calibration,
1436 you must reprogram the unit completely, so this entry simply
1437 shows the current value and doesn't allow any changes.
1442 <title>Flash Image</title>
1444 This reprograms any Altus Metrum device by using a TeleMetrum
1445 or TeleDongle as a programming dongle. Please read the
1446 directions for flashing devices in the Updating Device
1447 Firmware chapter below.
1450 Once you have the programmer and target devices connected,
1451 push the 'Flash Image' button. That will present a dialog box
1452 listing all of the connected devices. Carefully select the
1453 programmer device, not the device to be programmed.
1456 Next, select the image to flash to the device. These are named
1457 with the product name and firmware version. The file selector
1458 will start in the directory containing the firmware included
1459 with the AltosUI package. Navigate to the directory containing
1460 the desired firmware if it isn't there.
1463 Next, a small dialog containing the device serial number and
1464 RF calibration values should appear. If these values are
1465 incorrect (possibly due to a corrupted image in the device),
1466 enter the correct values here.
1469 Finally, a dialog containing a progress bar will follow the
1470 programming process.
1473 When programming is complete, the target device will
1474 reboot. Note that if the target device is connected via USB, you
1475 will have to unplug it and then plug it back in for the USB
1476 connection to reset so that you can communicate with the device
1481 <title>Fire Igniter</title>
1483 This activates the igniter circuits in TeleMetrum to help test
1484 recovery systems deployment. Because this command can operate
1485 over the Packet Command Link, you can prepare the rocket as
1486 for flight and then test the recovery system without needing
1487 to snake wires inside the air-frame.
1490 Selecting the 'Fire Igniter' button brings up the usual device
1491 selection dialog. Pick the desired TeleDongle or TeleMetrum
1492 device. This brings up another window which shows the current
1493 continuity test status for both apogee and main charges.
1496 Next, select the desired igniter to fire. This will enable the
1500 Select the 'Arm' button. This enables the 'Fire' button. The
1501 word 'Arm' is replaced by a countdown timer indicating that
1502 you have 10 seconds to press the 'Fire' button or the system
1503 will deactivate, at which point you start over again at
1504 selecting the desired igniter.
1508 <title>Scan Channels</title>
1510 This listens for telemetry packets on all of the configured
1511 frequencies, displaying information about each device it
1512 receives a packet from. You can select which of the three
1513 telemetry formats should be tried; by default, it only listens
1514 for the standard telemetry packets used in v1.0 and later
1519 <title>Load Maps</title>
1521 Before heading out to a new launch site, you can use this to
1522 load satellite images in case you don't have internet
1523 connectivity at the site. This loads a fairly large area
1524 around the launch site, which should cover any flight you're likely to make.
1527 There's a drop-down menu of launch sites we know about; if
1528 your favorites aren't there, please let us know the lat/lon
1529 and name of the site. The contents of this list are actually
1530 downloaded at run-time, so as new sites are sent in, they'll
1531 get automatically added to this list.
1534 If the launch site isn't in the list, you can manually enter the lat/lon values
1537 Clicking the 'Load Map' button will fetch images from Google
1538 Maps; note that Google limits how many images you can fetch at
1539 once, so if you load more than one launch site, you may get
1540 some gray areas in the map which indicate that Google is tired
1541 of sending data to you. Try again later.
1545 <title>Monitor Idle</title>
1547 This brings up a dialog similar to the Monitor Flight UI,
1548 except it works with the altimeter in "idle" mode by sending
1549 query commands to discover the current state rather than
1550 listening for telemetry packets.
1555 <title>Using Altus Metrum Products</title>
1557 <title>Being Legal</title>
1559 First off, in the US, you need an <ulink url="http://www.altusmetrum.org/Radio/">amateur radio license</ulink> or
1560 other authorization to legally operate the radio transmitters that are part
1565 <title>In the Rocket</title>
1567 In the rocket itself, you just need a <ulink url="http://www.altusmetrum.org/TeleMetrum/">TeleMetrum</ulink> or
1568 <ulink url="http://www.altusmetrum.org/TeleMini/">TeleMini</ulink> board and
1569 a single-cell, 3.7 volt nominal Li-Po rechargeable battery. An
1570 850mAh battery weighs less than a 9V alkaline battery, and will
1571 run a TeleMetrum for hours.
1572 A 110mAh battery weighs less than a triple A battery and will run a TeleMetrum for
1573 a few hours, or a TeleMini for much (much) longer.
1576 By default, we ship the altimeters with a simple wire antenna. If your
1577 electronics bay or the air-frame it resides within is made of carbon fiber,
1578 which is opaque to RF signals, you may choose to have an SMA connector
1579 installed so that you can run a coaxial cable to an antenna mounted
1580 elsewhere in the rocket.
1584 <title>On the Ground</title>
1586 To receive the data stream from the rocket, you need an antenna and short
1587 feed-line connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. If possible, use an SMA to BNC
1588 adapter instead of feedline between the antenna feedpoint and
1589 TeleDongle, as this will give you the best performance. The
1590 TeleDongle in turn plugs directly into the USB port on a notebook
1591 computer. Because TeleDongle looks like a simple serial port, your computer
1592 does not require special device drivers... just plug it in.
1595 The GUI tool, AltosUI, is written in Java and runs across
1596 Linux, Mac OS and Windows. There's also a suite of C tools
1597 for Linux which can perform most of the same tasks.
1600 After the flight, you can use the radio link to extract the more detailed data
1601 logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
1602 TeleMetrum board directly. Pulling out the data without having to open up
1603 the rocket is pretty cool! A USB cable is also how you charge the Li-Po
1604 battery, so you'll want one of those anyway... the same cable used by lots
1605 of digital cameras and other modern electronic stuff will work fine.
1608 If your TeleMetrum-equipped rocket lands out of sight, you may enjoy having a hand-held GPS
1609 receiver, so that you can put in a way-point for the last reported rocket
1610 position before touch-down. This makes looking for your rocket a lot like
1611 Geo-Caching... just go to the way-point and look around starting from there.
1614 You may also enjoy having a ham radio "HT" that covers the 70cm band... you
1615 can use that with your antenna to direction-find the rocket on the ground
1616 the same way you can use a Walston or Beeline tracker. This can be handy
1617 if the rocket is hiding in sage brush or a tree, or if the last GPS position
1618 doesn't get you close enough because the rocket dropped into a canyon, or
1619 the wind is blowing it across a dry lake bed, or something like that... Keith
1620 and Bdale both currently own and use the Yaesu VX-7R at launches.
1623 So, to recap, on the ground the hardware you'll need includes:
1624 <orderedlist inheritnum='inherit' numeration='arabic'>
1626 an antenna and feed-line or adapter
1635 optionally, a hand-held GPS receiver
1638 optionally, an HT or receiver covering 435 MHz
1643 The best hand-held commercial directional antennas we've found for radio
1644 direction finding rockets are from
1645 <ulink url="http://www.arrowantennas.com/" >
1648 The 440-3 and 440-5 are both good choices for finding a
1649 TeleMetrum- or TeleMini- equipped rocket when used with a suitable
1650 70cm HT. TeleDongle and an SMA to BNC adapter fit perfectly
1651 between the driven element and reflector of Arrow antennas.
1655 <title>Data Analysis</title>
1657 Our software makes it easy to log the data from each flight, both the
1658 telemetry received during the flight itself, and the more
1659 complete data log recorded in the flash memory on the altimeter
1660 board. Once this data is on your computer, our post-flight tools make it
1661 easy to quickly get to the numbers everyone wants, like apogee altitude,
1662 max acceleration, and max velocity. You can also generate and view a
1663 standard set of plots showing the altitude, acceleration, and
1664 velocity of the rocket during flight. And you can even export a TeleMetrum data file
1665 usable with Google Maps and Google Earth for visualizing the flight path
1666 in two or three dimensions!
1669 Our ultimate goal is to emit a set of files for each flight that can be
1670 published as a web page per flight, or just viewed on your local disk with
1675 <title>Future Plans</title>
1677 In the future, we intend to offer "companion boards" for the rocket
1678 that will plug in to TeleMetrum to collect additional data, provide
1679 more pyro channels, and so forth.
1682 Also under design is a new flight computer with more sensors, more
1683 pyro channels, and a more powerful radio system designed for use
1684 in multi-stage, complex, and extreme altitude projects.
1687 We are also working on alternatives to TeleDongle. One is a
1688 a stand-alone, hand-held ground terminal that will allow monitoring
1689 the rocket's status, collecting data during flight, and logging data
1690 after flight without the need for a notebook computer on the
1691 flight line. Particularly since it is so difficult to read most
1692 notebook screens in direct sunlight, we think this will be a great
1693 thing to have. We are also working on a TeleDongle variant with
1694 Bluetooth that will work with Android phones and tablets.
1697 Because all of our work is open, both the hardware designs and the
1698 software, if you have some great idea for an addition to the current
1699 Altus Metrum family, feel free to dive in and help! Or let us know
1700 what you'd like to see that we aren't already working on, and maybe
1701 we'll get excited about it too...
1705 <ulink url="http://altusmetrum.org/">web site</ulink> for more news
1706 and information as our family of products evolves!
1711 <title>Altimeter Installation Recommendations</title>
1713 Building high-power rockets that fly safely is hard enough. Mix
1714 in some sophisticated electronics and a bunch of radio energy
1715 and oftentimes you find few perfect solutions. This chapter
1716 contains some suggestions about how to install Altus Metrum
1717 products into the rocket air-frame, including how to safely and
1718 reliably mix a variety of electronics into the same air-frame.
1721 <title>Mounting the Altimeter</title>
1723 The first consideration is to ensure that the altimeter is
1724 securely fastened to the air-frame. For TeleMetrum, we use
1725 nylon standoffs and nylon screws; they're good to at least 50G
1726 and cannot cause any electrical issues on the board. For
1727 TeleMini, we usually cut small pieces of 1/16" balsa to fit
1728 under the screw holes, and then take 2x56 nylon screws and
1729 screw them through the TeleMini mounting holes, through the
1730 balsa and into the underlying material.
1732 <orderedlist inheritnum='inherit' numeration='arabic'>
1734 Make sure TeleMetrum is aligned precisely along the axis of
1735 acceleration so that the accelerometer can accurately
1736 capture data during the flight.
1739 Watch for any metal touching components on the
1740 board. Shorting out connections on the bottom of the board
1741 can cause the altimeter to fail during flight.
1746 <title>Dealing with the Antenna</title>
1748 The antenna supplied is just a piece of solid, insulated,
1749 wire. If it gets damaged or broken, it can be easily
1750 replaced. It should be kept straight and not cut; bending or
1751 cutting it will change the resonant frequency and/or
1752 impedance, making it a less efficient radiator and thus
1753 reducing the range of the telemetry signal.
1756 Keeping metal away from the antenna will provide better range
1757 and a more even radiation pattern. In most rockets, it's not
1758 entirely possible to isolate the antenna from metal
1759 components; there are often bolts, all-thread and wires from other
1760 electronics to contend with. Just be aware that the more stuff
1761 like this around the antenna, the lower the range.
1764 Make sure the antenna is not inside a tube made or covered
1765 with conducting material. Carbon fiber is the most common
1766 culprit here -- CF is a good conductor and will effectively
1767 shield the antenna, dramatically reducing signal strength and
1768 range. Metallic flake paint is another effective shielding
1769 material which is to be avoided around any antennas.
1772 If the ebay is large enough, it can be convenient to simply
1773 mount the altimeter at one end and stretch the antenna out
1774 inside. Taping the antenna to the sled can keep it straight
1775 under acceleration. If there are metal rods, keep the
1776 antenna as far away as possible.
1779 For a shorter ebay, it's quite practical to have the antenna
1780 run through a bulkhead and into an adjacent bay. Drill a small
1781 hole in the bulkhead, pass the antenna wire through it and
1782 then seal it up with glue or clay. We've also used acrylic
1783 tubing to create a cavity for the antenna wire. This works a
1784 bit better in that the antenna is known to stay straight and
1785 not get folded by recovery components in the bay. Angle the
1786 tubing towards the side wall of the rocket and it ends up
1787 consuming very little space.
1790 If you need to place the antenna at a distance from the
1791 altimeter, you can replace the antenna with an edge-mounted
1792 SMA connector, and then run 50Ω coax from the board to the
1793 antenna. Building a remote antenna is beyond the scope of this
1798 <title>Preserving GPS Reception</title>
1800 The GPS antenna and receiver in TeleMetrum are highly
1801 sensitive and normally have no trouble tracking enough
1802 satellites to provide accurate position information for
1803 recovering the rocket. However, there are many ways to
1804 attenuate the GPS signal.
1805 <orderedlist inheritnum='inherit' numeration='arabic'>
1807 Conductive tubing or coatings. Carbon fiber and metal
1808 tubing, or metallic paint will all dramatically attenuate the
1809 GPS signal. We've never heard of anyone successfully
1810 receiving GPS from inside these materials.
1813 Metal components near the GPS patch antenna. These will
1814 de-tune the patch antenna, changing the resonant frequency
1815 away from the L1 carrier and reduce the effectiveness of the
1816 antenna. You can place as much stuff as you like beneath the
1817 antenna as that's covered with a ground plane. But, keep
1818 wires and metal out from above the patch antenna.
1824 <title>Radio Frequency Interference</title>
1826 Any altimeter will generate RFI; the digital circuits use
1827 high-frequency clocks that spray radio interference across a
1828 wide band. Altus Metrum altimeters generate intentional radio
1829 signals as well, increasing the amount of RF energy around the board.
1832 Rocketry altimeters also use precise sensors measuring air
1833 pressure and acceleration. Tiny changes in voltage can cause
1834 these sensor readings to vary by a huge amount. When the
1835 sensors start mis-reporting data, the altimeter can either
1836 fire the igniters at the wrong time, or not fire them at all.
1839 Voltages are induced when radio frequency energy is
1840 transmitted from one circuit to another. Here are things that
1841 influence the induced voltage and current:
1845 Keep wires from different circuits apart. Moving circuits
1846 further apart will reduce RFI.
1849 Avoid parallel wires from different circuits. The longer two
1850 wires run parallel to one another, the larger the amount of
1851 transferred energy. Cross wires at right angles to reduce
1855 Twist wires from the same circuits. Two wires the same
1856 distance from the transmitter will get the same amount of
1857 induced energy which will then cancel out. Any time you have
1858 a wire pair running together, twist the pair together to
1859 even out distances and reduce RFI. For altimeters, this
1860 includes battery leads, switch hookups and igniter
1864 Avoid resonant lengths. Know what frequencies are present
1865 in the environment and avoid having wire lengths near a
1866 natural resonant length. Altusmetrum products transmit on the
1867 70cm amateur band, so you should avoid lengths that are a
1868 simple ratio of that length; essentially any multiple of 1/4
1869 of the wavelength (17.5cm).
1874 <title>The Barometric Sensor</title>
1876 Altusmetrum altimeters measure altitude with a barometric
1877 sensor, essentially measuring the amount of air above the
1878 rocket to figure out how high it is. A large number of
1879 measurements are taken as the altimeter initializes itself to
1880 figure out the pad altitude. Subsequent measurements are then
1881 used to compute the height above the pad.
1884 To accurately measure atmospheric pressure, the ebay
1885 containing the altimeter must be vented outside the
1886 air-frame. The vent must be placed in a region of linear
1887 airflow, have smooth edges, and away from areas of increasing or
1888 decreasing pressure.
1891 The barometric sensor in the altimeter is quite sensitive to
1892 chemical damage from the products of APCP or BP combustion, so
1893 make sure the ebay is carefully sealed from any compartment
1894 which contains ejection charges or motors.
1898 <title>Ground Testing</title>
1900 The most important aspect of any installation is careful
1901 ground testing. Bringing an air-frame up to the LCO table which
1902 hasn't been ground tested can lead to delays or ejection
1903 charges firing on the pad, or, even worse, a recovery system
1907 Do a 'full systems' test that includes wiring up all igniters
1908 without any BP and turning on all of the electronics in flight
1909 mode. This will catch any mistakes in wiring and any residual
1910 RFI issues that might accidentally fire igniters at the wrong
1911 time. Let the air-frame sit for several minutes, checking for
1912 adequate telemetry signal strength and GPS lock. If any igniters
1913 fire unexpectedly, find and resolve the issue before loading any
1917 Ground test the ejection charges. Prepare the rocket for
1918 flight, loading ejection charges and igniters. Completely
1919 assemble the air-frame and then use the 'Fire Igniters'
1920 interface through a TeleDongle to command each charge to
1921 fire. Make sure the charge is sufficient to robustly separate
1922 the air-frame and deploy the recovery system.
1927 <title>Updating Device Firmware</title>
1929 The big concept to understand is that you have to use a
1930 TeleDongle as a programmer to update a TeleMetrum or TeleMini,
1931 and a TeleMetrum or other TeleDongle to program the TeleDongle
1932 Due to limited memory resources in the cc1111, we don't support
1933 programming directly over USB.
1936 You may wish to begin by ensuring you have current firmware images.
1937 These are distributed as part of the AltOS software bundle that
1938 also includes the AltosUI ground station program. Newer ground
1939 station versions typically work fine with older firmware versions,
1940 so you don't need to update your devices just to try out new
1941 software features. You can always download the most recent
1942 version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
1945 We recommend updating the altimeter first, before updating TeleDongle.
1948 <title>Updating TeleMetrum Firmware</title>
1949 <orderedlist inheritnum='inherit' numeration='arabic'>
1951 Find the 'programming cable' that you got as part of the starter
1952 kit, that has a red 8-pin MicroMaTch connector on one end and a
1953 red 4-pin MicroMaTch connector on the other end.
1956 Take the 2 screws out of the TeleDongle case to get access
1957 to the circuit board.
1960 Plug the 8-pin end of the programming cable to the
1961 matching connector on the TeleDongle, and the 4-pin end to the
1962 matching connector on the TeleMetrum.
1963 Note that each MicroMaTch connector has an alignment pin that
1964 goes through a hole in the PC board when you have the cable
1968 Attach a battery to the TeleMetrum board.
1971 Plug the TeleDongle into your computer's USB port, and power
1975 Run AltosUI, and select 'Flash Image' from the File menu.
1978 Pick the TeleDongle device from the list, identifying it as the
1982 Select the image you want put on the TeleMetrum, which should have a
1983 name in the form telemetrum-v1.2-1.0.0.ihx. It should be visible
1984 in the default directory, if not you may have to poke around
1985 your system to find it.
1988 Make sure the configuration parameters are reasonable
1989 looking. If the serial number and/or RF configuration
1990 values aren't right, you'll need to change them.
1993 Hit the 'OK' button and the software should proceed to flash
1994 the TeleMetrum with new firmware, showing a progress bar.
1997 Confirm that the TeleMetrum board seems to have updated OK, which you
1998 can do by plugging in to it over USB and using a terminal program
1999 to connect to the board and issue the 'v' command to check
2003 If something goes wrong, give it another try.
2008 <title>Updating TeleMini Firmware</title>
2009 <orderedlist inheritnum='inherit' numeration='arabic'>
2011 You'll need a special 'programming cable' to reprogram the
2012 TeleMini. It's available on the Altus Metrum web store, or
2013 you can make your own using an 8-pin MicroMaTch connector on
2014 one end and a set of four pins on the other.
2017 Take the 2 screws out of the TeleDongle case to get access
2018 to the circuit board.
2021 Plug the 8-pin end of the programming cable to the matching
2022 connector on the TeleDongle, and the 4-pins into the holes
2023 in the TeleMini circuit board. Note that the MicroMaTch
2024 connector has an alignment pin that goes through a hole in
2025 the PC board when you have the cable oriented correctly, and
2026 that pin 1 on the TeleMini board is marked with a square pad
2027 while the other pins have round pads.
2030 Attach a battery to the TeleMini board.
2033 Plug the TeleDongle into your computer's USB port, and power
2037 Run AltosUI, and select 'Flash Image' from the File menu.
2040 Pick the TeleDongle device from the list, identifying it as the
2044 Select the image you want put on the TeleMini, which should have a
2045 name in the form telemini-v1.0-1.0.0.ihx. It should be visible
2046 in the default directory, if not you may have to poke around
2047 your system to find it.
2050 Make sure the configuration parameters are reasonable
2051 looking. If the serial number and/or RF configuration
2052 values aren't right, you'll need to change them.
2055 Hit the 'OK' button and the software should proceed to flash
2056 the TeleMini with new firmware, showing a progress bar.
2059 Confirm that the TeleMini board seems to have updated OK, which you
2060 can do by configuring it over the radio link through the TeleDongle, or
2061 letting it come up in "flight" mode and listening for telemetry.
2064 If something goes wrong, give it another try.
2069 <title>Updating TeleDongle Firmware</title>
2071 Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
2072 firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
2074 <orderedlist inheritnum='inherit' numeration='arabic'>
2076 Find the 'programming cable' that you got as part of the starter
2077 kit, that has a red 8-pin MicroMaTch connector on one end and a
2078 red 4-pin MicroMaTch connector on the other end.
2081 Find the USB cable that you got as part of the starter kit, and
2082 plug the "mini" end in to the mating connector on TeleMetrum or TeleDongle.
2085 Take the 2 screws out of the TeleDongle case to get access
2086 to the circuit board.
2089 Plug the 8-pin end of the programming cable to the
2090 matching connector on the programmer, and the 4-pin end to the
2091 matching connector on the TeleDongle.
2092 Note that each MicroMaTch connector has an alignment pin that
2093 goes through a hole in the PC board when you have the cable
2097 Attach a battery to the TeleMetrum board if you're using one.
2100 Plug both the programmer and the TeleDongle into your computer's USB
2101 ports, and power up the programmer.
2104 Run AltosUI, and select 'Flash Image' from the File menu.
2107 Pick the programmer device from the list, identifying it as the
2111 Select the image you want put on the TeleDongle, which should have a
2112 name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
2113 in the default directory, if not you may have to poke around
2114 your system to find it.
2117 Make sure the configuration parameters are reasonable
2118 looking. If the serial number and/or RF configuration
2119 values aren't right, you'll need to change them. The TeleDongle
2120 serial number is on the "bottom" of the circuit board, and can
2121 usually be read through the translucent blue plastic case without
2122 needing to remove the board from the case.
2125 Hit the 'OK' button and the software should proceed to flash
2126 the TeleDongle with new firmware, showing a progress bar.
2129 Confirm that the TeleDongle board seems to have updated OK, which you
2130 can do by plugging in to it over USB and using a terminal program
2131 to connect to the board and issue the 'v' command to check
2132 the version, etc. Once you're happy, remove the programming cable
2133 and put the cover back on the TeleDongle.
2136 If something goes wrong, give it another try.
2140 Be careful removing the programming cable from the locking 8-pin
2141 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
2142 screwdriver or knife blade to gently pry the locking ears out
2143 slightly to extract the connector. We used a locking connector on
2144 TeleMetrum to help ensure that the cabling to companion boards
2145 used in a rocket don't ever come loose accidentally in flight.
2150 <title>Hardware Specifications</title>
2152 <title>TeleMetrum Specifications</title>
2156 Recording altimeter for model rocketry.
2161 Supports dual deployment (can fire 2 ejection charges).
2166 70cm ham-band transceiver for telemetry down-link.
2171 Barometric pressure sensor good to 45k feet MSL.
2176 1-axis high-g accelerometer for motor characterization, capable of
2177 +/- 50g using default part.
2182 On-board, integrated GPS receiver with 5Hz update rate capability.
2187 On-board 1 megabyte non-volatile memory for flight data storage.
2192 USB interface for battery charging, configuration, and data recovery.
2197 Fully integrated support for Li-Po rechargeable batteries.
2202 Uses Li-Po to fire e-matches, can be modified to support
2203 optional separate pyro battery if needed.
2208 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
2214 <title>TeleMini Specifications</title>
2218 Recording altimeter for model rocketry.
2223 Supports dual deployment (can fire 2 ejection charges).
2228 70cm ham-band transceiver for telemetry down-link.
2233 Barometric pressure sensor good to 45k feet MSL.
2238 On-board 5 kilobyte non-volatile memory for flight data storage.
2243 RF interface for configuration, and data recovery.
2248 Support for Li-Po rechargeable batteries, using an external charger.
2253 Uses Li-Po to fire e-matches, can be modified to support
2254 optional separate pyro battery if needed.
2259 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube.
2268 TeleMetrum seems to shut off when disconnected from the
2269 computer. Make sure the battery is adequately charged. Remember the
2270 unit will pull more power than the USB port can deliver before the
2271 GPS enters "locked" mode. The battery charges best when TeleMetrum
2275 It's impossible to stop the TeleDongle when it's in "p" mode, I have
2276 to unplug the USB cable? Make sure you have tried to "escape out" of
2277 this mode. If this doesn't work the reboot procedure for the
2278 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
2279 outgoing buffer IF your "escape out" ('~~') does not work.
2280 At this point using either 'ao-view' (or possibly
2281 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
2285 The amber LED (on the TeleMetrum) lights up when both
2286 battery and USB are connected. Does this mean it's charging?
2287 Yes, the yellow LED indicates the charging at the 'regular' rate.
2288 If the led is out but the unit is still plugged into a USB port,
2289 then the battery is being charged at a 'trickle' rate.
2292 There are no "dit-dah-dah-dit" sound or lights like the manual mentions?
2293 That's the "pad" mode. Weak batteries might be the problem.
2294 It is also possible that the TeleMetrum is horizontal and the output
2295 is instead a "dit-dit" meaning 'idle'. For TeleMini, it's possible that
2296 it received a command packet which would have left it in "pad" mode.
2299 How do I save flight data?
2300 Live telemetry is written to file(s) whenever AltosUI is connected
2301 to the TeleDongle. The file area defaults to ~/TeleMetrum
2302 but is easily changed using the menus in AltosUI. The files that
2303 are written end in '.telem'. The after-flight
2304 data-dumped files will end in .eeprom and represent continuous data
2305 unlike the .telem files that are subject to losses
2306 along the RF data path.
2307 See the above instructions on what and how to save the eeprom stored
2308 data after physically retrieving your altimeter. Make sure to save
2309 the on-board data after each flight; while the TeleMetrum can store
2310 multiple flights, you never know when you'll lose the altimeter...
2314 <title>Notes for Older Software</title>
2317 Before AltosUI was written, using Altus Metrum devices required
2318 some finesse with the Linux command line. There was a limited
2319 GUI tool, ao-view, which provided functionality similar to the
2320 Monitor Flight window in AltosUI, but everything else was a
2321 fairly 80's experience. This appendix includes documentation for
2322 using that software.
2326 Both TeleMetrum and TeleDongle can be directly communicated
2327 with using USB ports. The first thing you should try after getting
2328 both units plugged into to your computer's USB port(s) is to run
2329 'ao-list' from a terminal-window to see what port-device-name each
2330 device has been assigned by the operating system.
2331 You will need this information to access the devices via their
2332 respective on-board firmware and data using other command line
2333 programs in the AltOS software suite.
2336 TeleMini can be communicated with through a TeleDongle device
2337 over the radio link. When first booted, TeleMini listens for a
2338 TeleDongle device and if it receives a packet, it goes into
2339 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be
2340 launched. The easiest way to get it talking is to start the
2341 communication link on the TeleDongle and the power up the
2345 To access the device's firmware for configuration you need a terminal
2346 program such as you would use to talk to a modem. The software
2347 authors prefer using the program 'cu' which comes from the UUCP package
2348 on most Unix-like systems such as Linux. An example command line for
2349 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
2350 indicated from running the
2351 ao-list program. Another reasonable terminal program for Linux is
2352 'cutecom'. The default 'escape'
2353 character used by CU (i.e. the character you use to
2354 issue commands to cu itself instead of sending the command as input
2355 to the connected device) is a '~'. You will need this for use in
2356 only two different ways during normal operations. First is to exit
2357 the program by sending a '~.' which is called a 'escape-disconnect'
2358 and allows you to close-out from 'cu'. The
2359 second use will be outlined later.
2362 All of the Altus Metrum devices share the concept of a two level
2363 command set in their firmware.
2364 The first layer has several single letter commands. Once
2365 you are using 'cu' (or 'cutecom') sending (typing) a '?'
2366 returns a full list of these
2367 commands. The second level are configuration sub-commands accessed
2368 using the 'c' command, for
2369 instance typing 'c?' will give you this second level of commands
2370 (all of which require the
2371 letter 'c' to access). Please note that most configuration options
2372 are stored only in Flash memory; TeleDongle doesn't provide any storage
2373 for these options and so they'll all be lost when you unplug it.
2376 Try setting these configuration ('c' or second level menu) values. A good
2377 place to start is by setting your call sign. By default, the boards
2378 use 'N0CALL' which is cute, but not exactly legal!
2379 Spend a few minutes getting comfortable with the units, their
2380 firmware, and 'cu' (or possibly 'cutecom').
2381 For instance, try to send
2382 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
2383 Verify you can connect and disconnect from the units while in your
2384 terminal program by sending the escape-disconnect mentioned above.
2387 To set the radio frequency, use the 'c R' command to specify the
2388 radio transceiver configuration parameter. This parameter is computed
2389 using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
2390 the standard calibration reference frequency, 'S', (normally 434.550MHz):
2394 Round the result to the nearest integer value.
2395 As with all 'c' sub-commands, follow this with a 'c w' to write the
2396 change to the parameter block in the on-board flash on
2397 your altimeter board if you want the change to stay in place across reboots.
2400 To set the apogee delay, use the 'c d' command.
2401 As with all 'c' sub-commands, follow this with a 'c w' to write the
2402 change to the parameter block in the on-board DataFlash chip.
2405 To set the main deployment altitude, use the 'c m' command.
2406 As with all 'c' sub-commands, follow this with a 'c w' to write the
2407 change to the parameter block in the on-board DataFlash chip.
2410 To calibrate the radio frequency, connect the UHF antenna port to a
2411 frequency counter, set the board to 434.550MHz, and use the 'C'
2412 command to generate a CW carrier. Wait for the transmitter temperature
2413 to stabilize and the frequency to settle down.
2414 Then, divide 434.550 MHz by the
2415 measured frequency and multiply by the current radio cal value show
2416 in the 'c s' command. For an unprogrammed board, the default value
2417 is 1186611. Take the resulting integer and program it using the 'c f'
2418 command. Testing with the 'C' command again should show a carrier
2419 within a few tens of Hertz of the intended frequency.
2420 As with all 'c' sub-commands, follow this with a 'c w' to write the
2421 change to the parameter block in the on-board DataFlash chip.
2424 Note that the 'reboot' command, which is very useful on the altimeters,
2425 will likely just cause problems with the dongle. The *correct* way
2426 to reset the dongle is just to unplug and re-plug it.
2429 A fun thing to do at the launch site and something you can do while
2430 learning how to use these units is to play with the radio link access
2431 between an altimeter and the TeleDongle. Be aware that you *must* create
2432 some physical separation between the devices, otherwise the link will
2433 not function due to signal overload in the receivers in each device.
2436 Now might be a good time to take a break and read the rest of this
2437 manual, particularly about the two "modes" that the altimeters
2438 can be placed in. TeleMetrum uses the position of the device when booting
2439 up will determine whether the unit is in "pad" or "idle" mode. TeleMini
2440 enters "idle" mode when it receives a command packet within the first 5 seconds
2441 of being powered up, otherwise it enters "pad" mode.
2444 You can access an altimeter in idle mode from the TeleDongle's USB
2445 connection using the radio link
2446 by issuing a 'p' command to the TeleDongle. Practice connecting and
2447 disconnecting ('~~' while using 'cu') from the altimeter. If
2448 you cannot escape out of the "p" command, (by using a '~~' when in
2449 CU) then it is likely that your kernel has issues. Try a newer version.
2452 Using this radio link allows you to configure the altimeter, test
2453 fire e-matches and igniters from the flight line, check pyro-match
2454 continuity and so forth. You can leave the unit turned on while it
2455 is in 'idle mode' and then place the
2456 rocket vertically on the launch pad, walk away and then issue a
2457 reboot command. The altimeter will reboot and start sending data
2458 having changed to the "pad" mode. If the TeleDongle is not receiving
2459 this data, you can disconnect 'cu' from the TeleDongle using the
2460 procedures mentioned above and THEN connect to the TeleDongle from
2461 inside 'ao-view'. If this doesn't work, disconnect from the
2462 TeleDongle, unplug it, and try again after plugging it back in.
2465 In order to reduce the chance of accidental firing of pyrotechnic
2466 charges, the command to fire a charge is intentionally somewhat
2467 difficult to type, and the built-in help is slightly cryptic to
2468 prevent accidental echoing of characters from the help text back at
2469 the board from firing a charge. The command to fire the apogee
2470 drogue charge is 'i DoIt drogue' and the command to fire the main
2471 charge is 'i DoIt main'.
2474 On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
2475 and 'ao-view' will both auditorily announce and visually indicate
2477 Now you can launch knowing that you have a good data path and
2478 good satellite lock for flight data and recovery. Remember
2479 you MUST tell ao-view to connect to the TeleDongle explicitly in
2480 order for ao-view to be able to receive data.
2483 The altimeters provide RDF (radio direction finding) tones on
2484 the pad, during descent and after landing. These can be used to
2485 locate the rocket using a directional antenna; the signal
2486 strength providing an indication of the direction from receiver to rocket.
2489 TeleMetrum also provides GPS tracking data, which can further simplify
2490 locating the rocket once it has landed. (The last good GPS data
2491 received before touch-down will be on the data screen of 'ao-view'.)
2494 Once you have recovered the rocket you can download the eeprom
2495 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
2496 either a USB cable or over the radio link using TeleDongle.
2497 And by following the man page for 'ao-postflight' you can create
2498 various data output reports, graphs, and even KML data to see the
2499 flight trajectory in Google-earth. (Moving the viewing angle making
2500 sure to connect the yellow lines while in Google-earth is the proper
2504 As for ao-view.... some things are in the menu but don't do anything
2505 very useful. The developers have stopped working on ao-view to focus
2506 on a new, cross-platform ground station program. So ao-view may or
2507 may not be updated in the future. Mostly you just use
2508 the Log and Device menus. It has a wonderful display of the incoming
2509 flight data and I am sure you will enjoy what it has to say to you
2510 once you enable the voice output!
2514 <title>Drill Templates</title>
2516 These images, when printed, provide precise templates for the
2517 mounting holes in Altus Metrum flight computers
2520 <title>TeleMetrum template</title>
2522 TeleMetrum has overall dimensions of 1.000 x 2.750 inches, and the
2523 mounting holes are sized for use with 4-40 or M3 screws.
2525 <mediaobject id="TeleMetrumTemplate">
2527 <imagedata format="SVG" fileref="telemetrum.svg"/>
2532 <title>TeleMini template</title>
2534 TeleMini has overall dimensions of 0.500 x 1.500 inches, and the
2535 mounting holes are sized for use with 2-56 or M2 screws.
2537 <mediaobject id="TeleMiniTemplate">
2539 <imagedata format="SVG" fileref="telemini.svg"/>
2545 <title>Calibration</title>
2547 There are only two calibrations required for a TeleMetrum board, and
2548 only one for TeleDongle and TeleMini. All boards are shipped from
2549 the factory pre-calibrated, but the procedures are documented here
2550 in case they are ever needed. Re-calibration is not supported by
2551 AltosUI, you must connect to the board with a serial terminal program
2552 and interact directly with the on-board command interpreter to effect
2556 <title>Radio Frequency</title>
2558 The radio frequency is synthesized from a clock based on the 48 MHz
2559 crystal on the board. The actual frequency of this oscillator
2560 must be measured to generate a calibration constant. While our
2562 bandwidth is wide enough to allow boards to communicate even when
2563 their oscillators are not on exactly the same frequency, performance
2564 is best when they are closely matched.
2565 Radio frequency calibration requires a calibrated frequency counter.
2566 Fortunately, once set, the variation in frequency due to aging and
2567 temperature changes is small enough that re-calibration by customers
2568 should generally not be required.
2571 To calibrate the radio frequency, connect the UHF antenna port to a
2572 frequency counter, set the board to 434.550MHz, and use the 'C'
2573 command in the on-board command interpreter to generate a CW
2574 carrier. For TeleMetrum, this is best done over USB. For TeleMini,
2575 note that the only way to escape the 'C' command is via power cycle
2576 since the board will no longer be listening for commands once it
2577 starts generating a CW carrier.
2580 Wait for the transmitter temperature to stabilize and the frequency
2581 to settle down. Then, divide 434.550 MHz by the
2582 measured frequency and multiply by the current radio cal value show
2583 in the 'c s' command. For an unprogrammed board, the default value
2584 is 1186611. Take the resulting integer and program it using the 'c f'
2585 command. Testing with the 'C' command again should show a carrier
2586 within a few tens of Hertz of the intended frequency.
2587 As with all 'c' sub-commands, follow this with a 'c w' to write the
2588 change to the parameter block in the on-board DataFlash chip.
2591 Note that any time you re-do the radio frequency calibration, the
2592 radio frequency is reset to the default 434.550 Mhz. If you want
2593 to use another frequency, you will have to set that again after
2594 calibration is completed.
2598 <title>TeleMetrum Accelerometer</title>
2600 The TeleMetrum accelerometer we use has its own 5 volt power
2602 the output must be passed through a resistive voltage divider to match
2603 the input of our 3.3 volt ADC. This means that unlike the barometric
2604 sensor, the output of the acceleration sensor is not ratio-metric to
2605 the ADC converter, and calibration is required. Explicitly
2606 calibrating the accelerometers also allows us to load any device
2607 from a Freescale family that includes at least +/- 40g, 50g, 100g,
2608 and 200g parts. Using gravity,
2609 a simple 2-point calibration yields acceptable results capturing both
2610 the different sensitivities and ranges of the different accelerometer
2611 parts and any variation in power supply voltages or resistor values
2612 in the divider network.
2615 To calibrate the acceleration sensor, use the 'c a 0' command. You
2616 will be prompted to orient the board vertically with the UHF antenna
2617 up and press a key, then to orient the board vertically with the
2618 UHF antenna down and press a key. Note that the accuracy of this
2619 calibration depends primarily on how perfectly vertical and still
2620 the board is held during the cal process. As with all 'c'
2621 sub-commands, follow this with a 'c w' to write the
2622 change to the parameter block in the on-board DataFlash chip.
2625 The +1g and -1g calibration points are included in each telemetry
2626 frame and are part of the header stored in onboard flash to be
2627 downloaded after flight. We always store and return raw ADC
2628 samples for each sensor... so nothing is permanently "lost" or
2629 "damaged" if the calibration is poor.
2632 In the unlikely event an accel cal goes badly, it is possible
2633 that TeleMetrum may always come up in 'pad mode' and as such not be
2634 listening to either the USB or radio link. If that happens,
2635 there is a special hook in the firmware to force the board back
2636 in to 'idle mode' so you can re-do the cal. To use this hook, you
2637 just need to ground the SPI clock pin at power-on. This pin is
2638 available as pin 2 on the 8-pin companion connector, and pin 1 is
2639 ground. So either carefully install a fine-gauge wire jumper
2640 between the two pins closest to the index hole end of the 8-pin
2641 connector, or plug in the programming cable to the 8-pin connector
2642 and use a small screwdriver or similar to short the two pins closest
2643 to the index post on the 4-pin end of the programming cable, and
2644 power up the board. It should come up in 'idle mode' (two beeps),
2650 xmlns:xi="http://www.w3.org/2001/XInclude">
2651 <title>Release Notes</title>
2652 <simplesect><title>Version 1.1.1</title><xi:include href="release-notes-1.1.1.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2653 <simplesect><title>Version 1.1</title><xi:include href="release-notes-1.1.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2654 <simplesect><title>Version 1.0.1</title><xi:include href="release-notes-1.0.1.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2655 <simplesect><title>Version 0.9.2</title><xi:include href="release-notes-0.9.2.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2656 <simplesect><title>Version 0.9</title><xi:include href="release-notes-0.9.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2657 <simplesect><title>Version 0.8</title><xi:include href="release-notes-0.8.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2658 <simplesect><title>Version 0.7.1</title><xi:include href="release-notes-0.7.1.xsl" xpointer="xpointer(/article/*)"/></simplesect>
2662 <!-- LocalWords: Altusmetrum
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