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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>1.0</revnumber>
40 <date>24 August 2011</date>
42 Updated for software version 1.0. Note that 1.0 represents a
43 telemetry format change, meaning both ends of a link
44 (TeleMetrum/TeleMini and TeleDongle) must be updated or
45 communications will fail.
49 <revnumber>0.9</revnumber>
50 <date>18 January 2011</date>
52 Updated for software version 0.9. Note that 0.9 represents a
53 telemetry format change, meaning both ends of a link (TeleMetrum and
54 TeleDongle) must be updated or communications will fail.
58 <revnumber>0.8</revnumber>
59 <date>24 November 2010</date>
60 <revremark>Updated for software version 0.8 </revremark>
66 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing "The
67 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
68 Kit" which formed the basis of the original Getting Started chapter
69 in this manual. Bob was one of our first customers for a production
70 TeleMetrum, and his continued enthusiasm and contributions
71 are immensely gratifying and highly appreciated!
74 And thanks to Anthony (AJ) Towns for major contributions including
75 the AltosUI graphing and site map code and associated documentation.
76 Free software means that our customers and friends can become our
77 collaborators, and we certainly appreciate this level of
81 Have fun using these products, and we hope to meet all of you
82 out on the rocket flight line somewhere.
85 NAR #87103, TRA #12201
88 NAR #88757, TRA #12200
93 <title>Introduction and Overview</title>
95 Welcome to the Altus Metrum community! Our circuits and software reflect
96 our passion for both hobby rocketry and Free Software. We hope their
97 capabilities and performance will delight you in every way, but by
98 releasing all of our hardware and software designs under open licenses,
99 we also hope to empower you to take as active a role in our collective
103 The first device created for our community was TeleMetrum, a dual
104 deploy altimeter with fully integrated GPS and radio telemetry
105 as standard features, and a "companion interface" that will
106 support optional capabilities in the future.
109 The newest device is TeleMini, a dual deploy altimeter with
110 radio telemetry and radio direction finding. This device is only
111 13mm by 38mm (½ inch by 1½ inches) and can fit easily in an 18mm
115 Complementing TeleMetrum and TeleMini is TeleDongle, a USB to RF
116 interface for communicating with the altimeters. Combined with your
117 choice of antenna and
118 notebook computer, TeleDongle and our associated user interface software
119 form a complete ground station capable of logging and displaying in-flight
120 telemetry, aiding rocket recovery, then processing and archiving flight
121 data for analysis and review.
124 More products will be added to the Altus Metrum family over time, and
125 we currently envision that this will be a single, comprehensive manual
126 for the entire product family.
130 <title>Getting Started</title>
132 The first thing to do after you check the inventory of parts in your
133 "starter kit" is to charge the battery.
136 The TeleMetrum battery can be charged by plugging it into the
137 corresponding socket of the TeleMetrum and then using the USB A to
139 cable to plug the TeleMetrum into your computer's USB socket. The
140 TeleMetrum circuitry will charge the battery whenever it is plugged
141 in, because the TeleMetrum's on-off switch does NOT control the
145 When the GPS chip is initially searching for
146 satellites, TeleMetrum will consume more current than it can pull
147 from the USB port, so the battery must be attached in order to get
148 satellite lock. Once GPS is locked, the current consumption goes back
149 down enough to enable charging while
150 running. So it's a good idea to fully charge the battery as your
151 first item of business so there is no issue getting and maintaining
152 satellite lock. The yellow charge indicator led will go out when the
153 battery is nearly full and the charger goes to trickle charge. It
154 can take several hours to fully recharge a deeply discharged battery.
157 The TeleMini battery can be charged by disconnecting it from the
158 TeleMini board and plugging it into a standalone battery charger
159 board, and connecting that via a USB cable to a laptop or other USB
163 The other active device in the starter kit is the TeleDongle USB to
164 RF interface. If you plug it in to your Mac or Linux computer it should
165 "just work", showing up as a serial port device. Windows systems need
166 driver information that is part of the AltOS download to know that the
167 existing USB modem driver will work. We therefore recommend installing
168 our software before plugging in TeleDongle if you are using a Windows
169 computer. If you are using Linux and are having problems, try moving
170 to a fresher kernel (2.6.33 or newer), as the USB serial driver had
171 ugly bugs in some earlier versions.
174 Next you should obtain and install the AltOS software. These include
175 the AltosUI ground station program, current firmware images for
176 TeleMetrum, TeleMini and TeleDongle, and a number of standalone
177 utilities that are rarely needed. Pre-built binary packages are
178 available for Linux, Microsoft Windows, and recent MacOSX versions.
179 Full source code and build instructions are also available.
180 The latest version may always be downloaded from
181 <ulink url="http://altusmetrum.org/AltOS"/>.
185 <title>Handling Precautions</title>
187 All Altus Metrum products are sophisticated electronic devices.
188 When handled gently and properly installed in an air-frame, they
189 will deliver impressive results. However, as with all electronic
190 devices, there are some precautions you must take.
193 The Lithium Polymer rechargeable batteries have an
194 extraordinary power density. This is great because we can fly with
195 much less battery mass than if we used alkaline batteries or previous
196 generation rechargeable batteries... but if they are punctured
197 or their leads are allowed to short, they can and will release their
199 Thus we recommend that you take some care when handling our batteries
200 and consider giving them some extra protection in your air-frame. We
201 often wrap them in suitable scraps of closed-cell packing foam before
202 strapping them down, for example.
205 The barometric sensors used on both TeleMetrum and TeleMini are
206 sensitive to sunlight. In normal TeleMetrum mounting situations, it
207 and all of the other surface mount components
208 are "down" towards whatever the underlying mounting surface is, so
209 this is not normally a problem. Please consider this, though, when
210 designing an installation, for example, in an air-frame with a
211 see-through plastic payload bay. It is particularly important to
212 consider this with TeleMini, both because the baro sensor is on the
213 "top" of the board, and because many model rockets with payload bays
214 use clear plastic for the payload bay! Replacing these with an opaque
215 cardboard tube, painting them, or wrapping them with a layer of masking
216 tape are all reasonable approaches to keep the sensor out of direct
220 The barometric sensor sampling port must be able to "breathe",
221 both by not being covered by foam or tape or other materials that might
222 directly block the hole on the top of the sensor, and also by having a
223 suitable static vent to outside air.
226 As with all other rocketry electronics, Altus Metrum altimeters must
227 be protected from exposure to corrosive motor exhaust and ejection
232 <title>Hardware Overview</title>
234 TeleMetrum is a 1 inch by 2.75 inch circuit board. It was designed to
235 fit inside coupler for 29mm air-frame tubing, but using it in a tube that
236 small in diameter may require some creativity in mounting and wiring
237 to succeed! The presence of an accelerometer means TeleMetrum should
238 be aligned along the flight axis of the airframe, and by default the 1/4
239 wave UHF wire antenna should be on the nose-cone end of the board. The
240 antenna wire is about 7 inches long, and wiring for a power switch and
241 the e-matches for apogee and main ejection charges depart from the
242 fin can end of the board, meaning an ideal "simple" avionics
243 bay for TeleMetrum should have at least 10 inches of interior length.
246 TeleMini is a 0.5 inch by 1.5 inch circuit board. It was designed to
247 fit inside an 18mm air-frame tube, but using it in a tube that
248 small in diameter may require some creativity in mounting and wiring
249 to succeed! Since there is no accelerometer, TeleMini can be mounted
250 in any convenient orientation. The default 1/4
251 wave UHF wire antenna attached to the center of one end of
252 the board is about 7 inches long, and wiring for a power switch and
253 the e-matches for apogee and main ejection charges depart from the
254 other end of the board, meaning an ideal "simple" avionics
255 bay for TeleMini should have at least 9 inches of interior length.
258 A typical TeleMetrum or TeleMini installation involves attaching
259 only a suitable Lithium Polymer battery, a single pole switch for
260 power on/off, and two pairs of wires connecting e-matches for the
261 apogee and main ejection charges.
264 By default, we use the unregulated output of the Li-Po battery directly
265 to fire ejection charges. This works marvelously with standard
266 low-current e-matches like the J-Tek from MJG Technologies, and with
267 Quest Q2G2 igniters. However, if you want or need to use a separate
268 pyro battery, check out the "External Pyro Battery" section in this
269 manual for instructions on how to wire that up. The altimeters are
270 designed to work with an external pyro battery of no more than 15 volts.
273 Ejection charges are wired directly to the screw terminal block
274 at the aft end of the altimeter. You'll need a very small straight
275 blade screwdriver for these screws, such as you might find in a
276 jeweler's screwdriver set.
279 TeleMetrum also uses the screw terminal block for the power
280 switch leads. On TeleMini, the power switch leads are soldered
281 directly to the board and can be connected directly to a switch.
284 For most air-frames, the integrated antennas are more than
285 adequate. However, if you are installing in a carbon-fiber or
286 metal electronics bay which is opaque to RF signals, you may need to
287 use off-board external antennas instead. In this case, you can
288 order an altimeter with an SMA connector for the UHF antenna
289 connection, and, on TeleMetrum, you can unplug the integrated GPS
290 antenna and select an appropriate off-board GPS antenna with
291 cable terminating in a U.FL connector.
295 <title>System Operation</title>
297 <title>Firmware Modes </title>
299 The AltOS firmware build for the altimeters has two
300 fundamental modes, "idle" and "flight". Which of these modes
301 the firmware operates in is determined at start up time. For
302 TeleMetrum, the mode is controlled by the orientation of the
303 rocket (well, actually the board, of course...) at the time
304 power is switched on. If the rocket is "nose up", then
305 TeleMetrum assumes it's on a rail or rod being prepared for
306 launch, so the firmware chooses flight mode. However, if the
307 rocket is more or less horizontal, the firmware instead enters
308 idle mode. Since TeleMini doesn't have an accelerometer we can
309 use to determine orientation, "idle" mode is selected when the
310 board receives a command packet within the first five seconds
311 of operation; if no packet is received, the board enters
315 At power on, you will hear three beeps or see three flashes
316 ("S" in Morse code for start up) and then a pause while
317 the altimeter completes initialization and self test, and decides
318 which mode to enter next.
321 In flight or "pad" mode, the altimeter engages the flight
322 state machine, goes into transmit-only mode to
323 send telemetry, and waits for launch to be detected.
324 Flight mode is indicated by an "di-dah-dah-dit" ("P" for pad)
325 on the beeper or lights, followed by beeps or flashes
326 indicating the state of the pyrotechnic igniter continuity.
327 One beep/flash indicates apogee continuity, two beeps/flashes
328 indicate main continuity, three beeps/flashes indicate both
329 apogee and main continuity, and one longer "brap" sound or
330 rapidly alternating lights indicates no continuity. For a
331 dual deploy flight, make sure you're getting three beeps or
332 flashes before launching! For apogee-only or motor eject
333 flights, do what makes sense.
336 If idle mode is entered, you will hear an audible "di-dit" or see
337 two short flashes ("I" for idle), and the flight state machine is
338 disengaged, thus no ejection charges will fire. The altimeters also
339 listen for the radio link when in idle mode for requests sent via
340 TeleDongle. Commands can be issued to a TeleMetrum in idle mode
342 USB or the radio link equivalently. TeleMini only has the radio link.
343 Idle mode is useful for configuring the altimeter, for extracting data
344 from the on-board storage chip after flight, and for ground testing
348 One "neat trick" of particular value when TeleMetrum is used with
349 very large air-frames, is that you can power the board up while the
350 rocket is horizontal, such that it comes up in idle mode. Then you can
351 raise the air-frame to launch position, and issue a 'reset' command
352 via TeleDongle over the radio link to cause the altimeter to reboot and
353 come up in flight mode. This is much safer than standing on the top
354 step of a rickety step-ladder or hanging off the side of a launch
355 tower with a screw-driver trying to turn on your avionics before
362 TeleMetrum includes a complete GPS receiver. A complete explanation
363 of how GPS works is beyond the scope of this manual, but the bottom
364 line is that the TeleMetrum GPS receiver needs to lock onto at least
365 four satellites to obtain a solid 3 dimensional position fix and know
369 TeleMetrum provides backup power to the GPS chip any time a
370 battery is connected. This allows the receiver to "warm start" on
371 the launch rail much faster than if every power-on were a GPS
372 "cold start". In typical operations, powering up TeleMetrum
373 on the flight line in idle mode while performing final air-frame
374 preparation will be sufficient to allow the GPS receiver to cold
375 start and acquire lock. Then the board can be powered down during
376 RSO review and installation on a launch rod or rail. When the board
377 is turned back on, the GPS system should lock very quickly, typically
378 long before igniter installation and return to the flight line are
383 <title>Controlling An Altimeter Over The Radio Link</title>
385 One of the unique features of the Altus Metrum system is
386 the ability to create a two way command link between TeleDongle
387 and an altimeter using the digital radio transceivers built into
388 each device. This allows you to interact with the altimeter from
389 afar, as if it were directly connected to the computer.
392 Any operation which can be performed with TeleMetrum can
393 either be done with TeleMetrum directly connected to the
394 computer via the USB cable, or through the radio
395 link. TeleMini doesn't provide a USB connector and so it is
396 always communicated with over radio. Select the appropriate
397 TeleDongle device when the list of devices is presented and
398 AltosUI will interact with an altimeter over the radio link.
401 One oddity in the current interface is how AltosUI selects the
402 frequency for radio communications. Instead of providing
403 an interface to specifically configure the frequency, it uses
404 whatever frequency was most recently selected for the target
405 TeleDongle device in Monitor Flight mode. If you haven't ever
406 used that mode with the TeleDongle in question, select the
407 Monitor Flight button from the top level UI, and pick the
408 appropriate TeleDongle device. Once the flight monitoring
409 window is open, select the desired frequency and then close it
410 down again. All radio communications will now use that frequency.
415 Save Flight Data—Recover flight data from the rocket without
421 Configure altimeter apogee delays or main deploy heights
422 to respond to changing launch conditions. You can also
423 'reboot' the altimeter. Use this to remotely enable the
424 flight computer by turning TeleMetrum on in "idle" mode,
425 then once the air-frame is oriented for launch, you can
426 reboot the altimeter and have it restart in pad mode
427 without having to climb the scary ladder.
432 Fire Igniters—Test your deployment charges without snaking
433 wires out through holes in the air-frame. Simply assembly the
434 rocket as if for flight with the apogee and main charges
435 loaded, then remotely command the altimeter to fire the
441 Operation over the radio link for configuring an altimeter, ground
442 testing igniters, and so forth uses the same RF frequencies as flight
443 telemetry. To configure the desired TeleDongle frequency, select
444 the monitor flight tab, then use the frequency selector and
445 close the window before performing other desired radio operations.
448 TeleMetrum only enables packet command mode in 'idle' mode, so
449 make sure you have TeleMetrum lying horizontally when you turn
450 it on. Otherwise, TeleMetrum will start in 'pad' mode ready for
451 flight and will not be listening for command packets from TeleDongle.
454 TeleMini listens for a command packet for five seconds after
455 first being turned on, if it doesn't hear anything, it enters
456 'pad' mode, ready for flight and will no longer listen for
457 command packets. The easiest way to connect to TeleMini is to
458 initiate the command and select the TeleDongle device. At this
459 point, the TeleDongle will be attempting to communicate with
460 the TeleMini. Now turn TeleMini on, and it should immediately
461 start communicating with the TeleDongle and the desired
462 operation can be performed.
465 When packet command mode is enabled, you can monitor the link
466 by watching the lights on the
467 devices. The red LED will flash each time they
468 transmit a packet while the green LED will light up
469 on TeleDongle while it is waiting to receive a packet from
474 <title>Ground Testing </title>
476 An important aspect of preparing a rocket using electronic deployment
477 for flight is ground testing the recovery system. Thanks
478 to the bi-directional radio link central to the Altus Metrum system,
479 this can be accomplished in a TeleMetrum or TeleMini equipped rocket
480 with less work than you may be accustomed to with other systems. It
484 Just prep the rocket for flight, then power up the altimeter
485 in "idle" mode (placing air-frame horizontal for TeleMetrum or
486 selected the Configure Altimeter tab for TeleMini). This will cause
487 the firmware to go into "idle" mode, in which the normal flight
488 state machine is disabled and charges will not fire without
489 manual command. You can now command the altimeter to fire the apogee
490 or main charges from a safe distance using your computer and
491 TeleDongle and the Fire Igniter tab to complete ejection testing.
495 <title>Radio Link </title>
497 The chip our boards are based on incorporates an RF transceiver, but
498 it's not a full duplex system... each end can only be transmitting or
499 receiving at any given moment. So we had to decide how to manage the
503 By design, the altimeter firmware listens for the radio link when
504 it's in "idle mode", which
505 allows us to use the radio link to configure the rocket, do things like
506 ejection tests, and extract data after a flight without having to
507 crack open the air-frame. However, when the board is in "flight
508 mode", the altimeter only
509 transmits and doesn't listen at all. That's because we want to put
510 ultimate priority on event detection and getting telemetry out of
512 the radio in case the rocket crashes and we aren't able to extract
516 We don't use a 'normal packet radio' mode like APRS because they're
517 just too inefficient. The GFSK modulation we use is FSK with the
518 base-band pulses passed through a
519 Gaussian filter before they go into the modulator to limit the
520 transmitted bandwidth. When combined with the hardware forward error
521 correction support in the cc1111 chip, this allows us to have a very
522 robust 38.4 kilobit data link with only 10 milliwatts of transmit
523 power, a whip antenna in the rocket, and a hand-held Yagi on the
524 ground. We've had flights to above 21k feet AGL with great reception,
525 and calculations suggest we should be good to well over 40k feet AGL
526 with a 5-element yagi on the ground. We hope to fly boards to higher
527 altitudes over time, and would of course appreciate customer feedback
528 on performance in higher altitude flights!
532 <title>Configurable Parameters</title>
534 Configuring an Altus Metrum altimeter for flight is very
535 simple. Even on our baro-only TeleMini board, the use of a Kalman
536 filter means there is no need to set a "mach delay". The few
537 configurable parameters can all be set using AltosUI over USB or
538 or radio link via TeleDongle.
541 <title>Radio Frequencies</title>
543 The Altus Metrum boards support frequencies in the 70cm
544 band. By default, the configuration interface provides a
545 list of 10 common frequencies in 100kHz channels starting at
546 434.550MHz. However, the firmware supports use of
547 any 50kHz multiple within the 70cm band. At any given
548 launch, we highly recommend coordinating who will use each
549 frequency and when to avoid interference. And of course, both
550 altimeter and TeleDongle must be configured to the same
551 frequency to successfully communicate with each other.
554 To set the radio frequency, use the 'c R' command to specify the
555 radio transceiver configuration parameter. This parameter is computed
556 using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
557 the standard calibration reference frequency, 'S', (normally 434.550MHz):
561 Round the result to the nearest integer value.
562 As with all 'c' sub-commands, follow this with a 'c w' to write the
563 change to the parameter block in the on-board flash on
564 your altimeter board if you want the change to stay in place across reboots.
568 <title>Apogee Delay</title>
570 Apogee delay is the number of seconds after the altimeter detects flight
571 apogee that the drogue charge should be fired. In most cases, this
572 should be left at the default of 0. However, if you are flying
573 redundant electronics such as for an L3 certification, you may wish
574 to set one of your altimeters to a positive delay so that both
575 primary and backup pyrotechnic charges do not fire simultaneously.
578 To set the apogee delay, use the 'c d' command.
579 As with all 'c' sub-commands, follow this with a 'c w' to write the
580 change to the parameter block in the on-board DataFlash chip.
583 Please note that the Altus Metrum apogee detection algorithm
584 fires exactly at apogee. If you are also flying an
585 altimeter like the PerfectFlite MAWD, which only supports
586 selecting 0 or 1 seconds of apogee delay, you may wish to
587 set the MAWD to 0 seconds delay and set the TeleMetrum to
588 fire your backup 2 or 3 seconds later to avoid any chance of
589 both charges firing simultaneously. We've flown several
590 air-frames this way quite happily, including Keith's
595 <title>Main Deployment Altitude</title>
597 By default, the altimeter will fire the main deployment charge at an
598 elevation of 250 meters (about 820 feet) above ground. We think this
599 is a good elevation for most air-frames, but feel free to change this
600 to suit. In particular, if you are flying two altimeters, you may
602 deployment elevation for the backup altimeter to be something lower
603 than the primary so that both pyrotechnic charges don't fire
607 To set the main deployment altitude, use the 'c m' command.
608 As with all 'c' sub-commands, follow this with a 'c w' to write the
609 change to the parameter block in the on-board DataFlash chip.
614 <title>Calibration</title>
616 There are only two calibrations required for a TeleMetrum board, and
617 only one for TeleDongle and TeleMini.
620 <title>Radio Frequency</title>
622 The radio frequency is synthesized from a clock based on the 48 MHz
623 crystal on the board. The actual frequency of this oscillator must be
624 measured to generate a calibration constant. While our GFSK modulation
625 bandwidth is wide enough to allow boards to communicate even when
626 their oscillators are not on exactly the same frequency, performance
627 is best when they are closely matched.
628 Radio frequency calibration requires a calibrated frequency counter.
629 Fortunately, once set, the variation in frequency due to aging and
630 temperature changes is small enough that re-calibration by customers
631 should generally not be required.
634 To calibrate the radio frequency, connect the UHF antenna port to a
635 frequency counter, set the board to 434.550MHz, and use the 'C'
636 command to generate a CW carrier. Wait for the transmitter temperature
637 to stabilize and the frequency to settle down.
638 Then, divide 434.550 MHz by the
639 measured frequency and multiply by the current radio cal value show
640 in the 'c s' command. For an unprogrammed board, the default value
641 is 1186611. Take the resulting integer and program it using the 'c f'
642 command. Testing with the 'C' command again should show a carrier
643 within a few tens of Hertz of the intended frequency.
644 As with all 'c' sub-commands, follow this with a 'c w' to write the
645 change to the parameter block in the on-board DataFlash chip.
648 when the radio calibration value is changed, the radio
649 frequency value is reset to the same value, so you'll need
650 to recompute and reset the radio frequency value using the
651 new radio calibration value.
655 <title>TeleMetrum Accelerometer</title>
657 The TeleMetrum accelerometer we use has its own 5 volt power supply and
658 the output must be passed through a resistive voltage divider to match
659 the input of our 3.3 volt ADC. This means that unlike the barometric
660 sensor, the output of the acceleration sensor is not ratio-metric to
661 the ADC converter, and calibration is required. We also support the
662 use of any of several accelerometers from a Freescale family that
663 includes at least +/- 40g, 50g, 100g, and 200g parts. Using gravity,
664 a simple 2-point calibration yields acceptable results capturing both
665 the different sensitivities and ranges of the different accelerometer
666 parts and any variation in power supply voltages or resistor values
667 in the divider network.
670 To calibrate the acceleration sensor, use the 'c a 0' command. You
671 will be prompted to orient the board vertically with the UHF antenna
672 up and press a key, then to orient the board vertically with the
673 UHF antenna down and press a key.
674 As with all 'c' sub-commands, follow this with a 'c w' to write the
675 change to the parameter block in the on-board DataFlash chip.
678 The +1g and -1g calibration points are included in each telemetry
679 frame and are part of the header extracted by ao-dumplog after flight.
680 Note that we always store and return raw ADC samples for each
681 sensor... nothing is permanently "lost" or "damaged" if the
685 In the unlikely event an accel cal that goes badly, it is possible
686 that TeleMetrum may always come up in 'pad mode' and as such not be
687 listening to either the USB or radio link. If that happens,
688 there is a special hook in the firmware to force the board back
689 in to 'idle mode' so you can re-do the cal. To use this hook, you
690 just need to ground the SPI clock pin at power-on. This pin is
691 available as pin 2 on the 8-pin companion connector, and pin 1 is
692 ground. So either carefully install a fine-gauge wire jumper
693 between the two pins closest to the index hole end of the 8-pin
694 connector, or plug in the programming cable to the 8-pin connector
695 and use a small screwdriver or similar to short the two pins closest
696 to the index post on the 4-pin end of the programming cable, and
697 power up the board. It should come up in 'idle mode' (two beeps).
705 <title>AltosUI</title>
707 The AltosUI program provides a graphical user interface for
708 interacting with the Altus Metrum product family, including
709 TeleMetrum, TeleMini and TeleDongle. AltosUI can monitor telemetry data,
710 configure TeleMetrum, TeleMini and TeleDongle devices and many other
711 tasks. The primary interface window provides a selection of
712 buttons, one for each major activity in the system. This manual
713 is split into chapters, each of which documents one of the tasks
714 provided from the top-level toolbar.
717 <title>Monitor Flight</title>
718 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
720 Selecting this item brings up a dialog box listing all of the
721 connected TeleDongle devices. When you choose one of these,
722 AltosUI will create a window to display telemetry data as
723 received by the selected TeleDongle device.
726 All telemetry data received are automatically recorded in
727 suitable log files. The name of the files includes the current
728 date and rocket serial and flight numbers.
731 The radio frequency being monitored by the TeleDongle device is
732 displayed at the top of the window. You can configure the
733 frequency by clicking on the frequency box and selecting the desired
734 frequency. AltosUI remembers the last frequency selected for each
735 TeleDongle and selects that automatically the next time you use
739 Below the TeleDongle frequency selector, the window contains a few
740 significant pieces of information about the altimeter providing
741 the telemetry data stream:
745 <para>The configured call-sign</para>
748 <para>The device serial number</para>
751 <para>The flight number. Each altimeter remembers how many
757 The rocket flight state. Each flight passes through several
758 states including Pad, Boost, Fast, Coast, Drogue, Main and
764 The Received Signal Strength Indicator value. This lets
765 you know how strong a signal TeleDongle is receiving. The
766 radio inside TeleDongle operates down to about -99dBm;
767 weaker signals may not be receivable. The packet link uses
768 error correction and detection techniques which prevent
769 incorrect data from being reported.
774 Finally, the largest portion of the window contains a set of
775 tabs, each of which contain some information about the rocket.
776 They're arranged in 'flight order' so that as the flight
777 progresses, the selected tab automatically switches to display
778 data relevant to the current state of the flight. You can select
779 other tabs at any time. The final 'table' tab contains all of
780 the telemetry data in one place.
783 <title>Launch Pad</title>
785 The 'Launch Pad' tab shows information used to decide when the
786 rocket is ready for flight. The first elements include red/green
787 indicators, if any of these is red, you'll want to evaluate
788 whether the rocket is ready to launch:
792 Battery Voltage. This indicates whether the Li-Po battery
793 powering the TeleMetrum has sufficient charge to last for
794 the duration of the flight. A value of more than
795 3.7V is required for a 'GO' status.
800 Apogee Igniter Voltage. This indicates whether the apogee
801 igniter has continuity. If the igniter has a low
802 resistance, then the voltage measured here will be close
803 to the Li-Po battery voltage. A value greater than 3.2V is
804 required for a 'GO' status.
809 Main Igniter Voltage. This indicates whether the main
810 igniter has continuity. If the igniter has a low
811 resistance, then the voltage measured here will be close
812 to the Li-Po battery voltage. A value greater than 3.2V is
813 required for a 'GO' status.
818 On-board Data Logging. This indicates whether there is
819 space remaining on-board to store flight data for the
820 upcoming flight. If you've downloaded data, but failed
821 to erase flights, there may not be any space
822 left. TeleMetrum can store multiple flights, depending
823 on the configured maximum flight log size. TeleMini
824 stores only a single flight, so it will need to be
825 downloaded and erased after each flight to capture
826 data. This only affects on-board flight logging; the
827 altimeter will still transmit telemetry and fire
828 ejection charges at the proper times.
833 GPS Locked. For a TeleMetrum device, this indicates whether the GPS receiver is
834 currently able to compute position information. GPS requires
835 at least 4 satellites to compute an accurate position.
840 GPS Ready. For a TeleMetrum device, this indicates whether GPS has reported at least
841 10 consecutive positions without losing lock. This ensures
842 that the GPS receiver has reliable reception from the
848 The Launchpad tab also shows the computed launch pad position
849 and altitude, averaging many reported positions to improve the
855 <title>Ascent</title>
857 This tab is shown during Boost, Fast and Coast
858 phases. The information displayed here helps monitor the
859 rocket as it heads towards apogee.
862 The height, speed and acceleration are shown along with the
863 maximum values for each of them. This allows you to quickly
864 answer the most commonly asked questions you'll hear during
868 The current latitude and longitude reported by the TeleMetrum GPS are
869 also shown. Note that under high acceleration, these values
870 may not get updated as the GPS receiver loses position
871 fix. Once the rocket starts coasting, the receiver should
872 start reporting position again.
875 Finally, the current igniter voltages are reported as in the
876 Launch Pad tab. This can help diagnose deployment failures
877 caused by wiring which comes loose under high acceleration.
881 <title>Descent</title>
883 Once the rocket has reached apogee and (we hope) activated the
884 apogee charge, attention switches to tracking the rocket on
885 the way back to the ground, and for dual-deploy flights,
886 waiting for the main charge to fire.
889 To monitor whether the apogee charge operated correctly, the
890 current descent rate is reported along with the current
891 height. Good descent rates generally range from 15-30m/s.
894 For TeleMetrum altimeters, you can locate the rocket in the sky
895 using the elevation and
896 bearing information to figure out where to look. Elevation is
897 in degrees above the horizon. Bearing is reported in degrees
898 relative to true north. Range can help figure out how big the
899 rocket will appear. Note that all of these values are relative
900 to the pad location. If the elevation is near 90°, the rocket
901 is over the pad, not over you.
904 Finally, the igniter voltages are reported in this tab as
905 well, both to monitor the main charge as well as to see what
906 the status of the apogee charge is.
910 <title>Landed</title>
912 Once the rocket is on the ground, attention switches to
913 recovery. While the radio signal is generally lost once the
914 rocket is on the ground, the last reported GPS position is
915 generally within a short distance of the actual landing location.
918 The last reported GPS position is reported both by
919 latitude and longitude as well as a bearing and distance from
920 the launch pad. The distance should give you a good idea of
921 whether you'll want to walk or hitch a ride. Take the reported
922 latitude and longitude and enter them into your hand-held GPS
923 unit and have that compute a track to the landing location.
926 Both TeleMini and TeleMetrum will continue to transmit RDF
927 tones after landing, allowing you to locate the rocket by
928 following the radio signal. You may need to get away from
929 the clutter of the flight line, or even get up on a hill (or
930 your neighbor's RV) to receive the RDF signal.
933 The maximum height, speed and acceleration reported
934 during the flight are displayed for your admiring observers.
937 To get more detailed information about the flight, you can
938 click on the 'Graph Flight' button which will bring up a
939 graph window for the current flight.
943 <title>Site Map</title>
945 When the TeleMetrum gets a GPS fix, the Site Map tab will map
946 the rocket's position to make it easier for you to locate the
947 rocket, both while it is in the air, and when it has landed. The
948 rocket's state is indicated by color: white for pad, red for
949 boost, pink for fast, yellow for coast, light blue for drogue,
950 dark blue for main, and black for landed.
953 The map's scale is approximately 3m (10ft) per pixel. The map
954 can be dragged using the left mouse button. The map will attempt
955 to keep the rocket roughly centered while data is being received.
958 Images are fetched automatically via the Google Maps Static API,
959 and are cached for reuse. If map images cannot be downloaded,
960 the rocket's path will be traced on a dark gray background
964 You can pre-load images for your favorite launch sites
965 before you leave home; check out the 'Preload Maps' section below.
970 <title>Save Flight Data</title>
972 The altimeter records flight data to its internal flash memory.
973 The TeleMetrum data is recorded at a much higher rate than the telemetry
974 system can handle, and is not subject to radio drop-outs. As
975 such, it provides a more complete and precise record of the
976 flight. The 'Save Flight Data' button allows you to read the
977 flash memory and write it to disk. As TeleMini has only a barometer, it
978 records data at the same rate as the telemetry signal, but there will be
979 no data lost due to telemetry drop-outs.
982 Clicking on the 'Save Flight Data' button brings up a list of
983 connected TeleMetrum and TeleDongle devices. If you select a
984 TeleMetrum device, the flight data will be downloaded from that
985 device directly. If you select a TeleDongle device, flight data
986 will be downloaded from a TeleMetrum or TeleMini device connected via the
987 packet command link to the specified TeleDongle. See the chapter
988 on Packet Command Mode for more information about this.
991 After the device has been selected, a dialog showing the
992 flight data saved in the device will be shown allowing you to
993 select which flights to download and which to delete. With
994 version 0.9 or newer firmware, you must erase flights in order
995 for the space they consume to be reused by another
996 flight. This prevents you from accidentally losing flight data
997 if you neglect to download data before flying again. Note that
998 if there is no more space available in the device, then no
999 data will be recorded for a flight.
1002 The file name for each flight log is computed automatically
1003 from the recorded flight date, altimeter serial number and
1004 flight number information.
1008 <title>Replay Flight</title>
1010 Select this button and you are prompted to select a flight
1011 record file, either a .telem file recording telemetry data or a
1012 .eeprom file containing flight data saved from the altimeter
1016 Once a flight record is selected, the flight monitor interface
1017 is displayed and the flight is re-enacted in real time. Check
1018 the Monitor Flight chapter above to learn how this window operates.
1022 <title>Graph Data</title>
1024 Select this button and you are prompted to select a flight
1025 record file, either a .telem file recording telemetry data or a
1026 .eeprom file containing flight data saved from
1030 Once a flight record is selected, a window with two tabs is
1031 opened. The first tab contains a graph with acceleration
1032 (blue), velocity (green) and altitude (red) of the flight are
1033 plotted and displayed, measured in metric units. The
1034 apogee(yellow) and main(magenta) igniter voltages are also
1035 displayed; high voltages indicate continuity, low voltages
1036 indicate open circuits. The second tab contains some basic
1040 The graph can be zoomed into a particular area by clicking and
1041 dragging down and to the right. Once zoomed, the graph can be
1042 reset by clicking and dragging up and to the left. Holding down
1043 control and clicking and dragging allows the graph to be panned.
1044 The right mouse button causes a pop-up menu to be displayed, giving
1045 you the option save or print the plot.
1048 Note that telemetry files will generally produce poor graphs
1049 due to the lower sampling rate and missed telemetry packets.
1050 Use saved flight data for graphing where possible.
1054 <title>Export Data</title>
1056 This tool takes the raw data files and makes them available for
1057 external analysis. When you select this button, you are prompted to select a flight
1058 data file (either .eeprom or .telem will do, remember that
1059 .eeprom files contain higher resolution and more continuous
1060 data). Next, a second dialog appears which is used to select
1061 where to write the resulting file. It has a selector to choose
1062 between CSV and KML file formats.
1065 <title>Comma Separated Value Format</title>
1067 This is a text file containing the data in a form suitable for
1068 import into a spreadsheet or other external data analysis
1069 tool. The first few lines of the file contain the version and
1070 configuration information from the altimeter, then
1071 there is a single header line which labels all of the
1072 fields. All of these lines start with a '#' character which
1073 most tools can be configured to skip over.
1076 The remaining lines of the file contain the data, with each
1077 field separated by a comma and at least one space. All of
1078 the sensor values are converted to standard units, with the
1079 barometric data reported in both pressure, altitude and
1080 height above pad units.
1084 <title>Keyhole Markup Language (for Google Earth)</title>
1086 This is the format used by
1087 Googleearth to provide an overlay within that
1088 application. With this, you can use Googleearth to see the
1089 whole flight path in 3D.
1094 <title>Configure Altimeter</title>
1096 Select this button and then select either a TeleMetrum or
1097 TeleDongle Device from the list provided. Selecting a TeleDongle
1098 device will use Packet Command Mode to configure a remote
1099 altimeter. Learn how to use this in the Packet Command
1103 The first few lines of the dialog provide information about the
1104 connected device, including the product name,
1105 software version and hardware serial number. Below that are the
1106 individual configuration entries.
1109 At the bottom of the dialog, there are four buttons:
1114 Save. This writes any changes to the
1115 configuration parameter block in flash memory. If you don't
1116 press this button, any changes you make will be lost.
1121 Reset. This resets the dialog to the most recently saved values,
1122 erasing any changes you have made.
1127 Reboot. This reboots the device. Use this to
1128 switch from idle to pad mode by rebooting once the rocket is
1129 oriented for flight.
1134 Close. This closes the dialog. Any unsaved changes will be
1140 The rest of the dialog contains the parameters to be configured.
1143 <title>Main Deploy Altitude</title>
1145 This sets the altitude (above the recorded pad altitude) at
1146 which the 'main' igniter will fire. The drop-down menu shows
1147 some common values, but you can edit the text directly and
1148 choose whatever you like. If the apogee charge fires below
1149 this altitude, then the main charge will fire two seconds
1150 after the apogee charge fires.
1154 <title>Apogee Delay</title>
1156 When flying redundant electronics, it's often important to
1157 ensure that multiple apogee charges don't fire at precisely
1158 the same time as that can over pressurize the apogee deployment
1159 bay and cause a structural failure of the air-frame. The Apogee
1160 Delay parameter tells the flight computer to fire the apogee
1161 charge a certain number of seconds after apogee has been
1166 <title>Radio Frequency</title>
1168 This configures which of the configured frequencies to use for both
1169 telemetry and packet command mode. Note that if you set this
1170 value via packet command mode, you will have to reconfigure
1171 the TeleDongle frequency before you will be able to use packet
1176 <title>Radio Calibration</title>
1178 The radios in every Altus Metrum device are calibrated at the
1179 factory to ensure that they transmit and receive on the
1180 specified frequency. You can adjust that
1181 calibration by changing this value. To change the TeleDongle's
1182 calibration, you must reprogram the unit completely.
1186 <title>Callsign</title>
1188 This sets the call sign included in each telemetry packet. Set this
1189 as needed to conform to your local radio regulations.
1193 <title>Maximum Flight Log Size</title>
1195 This sets the space (in kilobytes) allocated for each flight
1196 log. The available space will be divided into chunks of this
1197 size. A smaller value will allow more flights to be stored,
1198 a larger value will record data from longer flights.
1201 During ascent, TeleMetrum records barometer and
1202 accelerometer values 100 times per second, other analog
1203 information (voltages and temperature) 6 times per second
1204 and GPS data once per second. During descent, the non-GPS
1205 data is recorded 1/10th as often. Each barometer +
1206 accelerometer record takes 8 bytes.
1209 The default, 192kB, will store over 200 seconds of data at
1210 the ascent rate, or over 2000 seconds of data at the descent
1211 rate. That's plenty for most flights. This leaves enough
1212 storage for five flights in a 1MB system, or 10 flights in a
1216 The configuration block takes the last available block of
1217 memory, on v1.0 boards that's just 256 bytes. However, the
1218 flash part on the v1.1 boards uses 64kB for each block.
1221 TeleMini has 5kB of on-board storage, which is plenty for a
1222 single flight. Make sure you download and delete the data
1223 before a subsequent flight or it will not log any data.
1227 <title>Ignite Mode</title>
1229 TeleMetrum and TeleMini provide two igniter channels as they
1230 were originally designed as dual-deploy flight
1231 computers. This configuration parameter allows the two
1232 channels to be used in different configurations.
1237 Dual Deploy. This is the usual mode of operation; the
1238 'apogee' channel is fired at apogee and the 'main'
1239 channel at the height above ground specified by the
1240 'Main Deploy Altitude' during descent.
1245 Redundant Apogee. This fires both channels at
1246 apogee, the 'apogee' channel first followed after a two second
1247 delay by the 'main' channel.
1252 Redundant Main. This fires both channels at the
1253 height above ground specified by the Main Deploy
1254 Altitude setting during descent. The 'apogee'
1255 channel is fired first, followed after a two second
1256 delay by the 'main' channel.
1262 <title>Pad Orientation</title>
1264 Because it includes an accelerometer, TeleMetrum is
1265 sensitive to the orientation of the board. By default, it
1266 expects the antenna end to point forward. This parameter
1267 allows that default to be changed, permitting the board to
1268 be mounted with the antenna pointing aft instead.
1273 Antenna Up. In this mode, the antenna end of the
1274 TeleMetrum board must point forward, in line with the
1275 expected flight path.
1280 Antenna Down. In this mode, the antenna end of the
1281 TeleMetrum board must point aft, in line with the
1282 expected flight path.
1289 <title>Configure AltosUI</title>
1291 This button presents a dialog so that you can configure the AltosUI global settings.
1294 <title>Voice Settings</title>
1296 AltosUI provides voice announcements during flight so that you
1297 can keep your eyes on the sky and still get information about
1298 the current flight status. However, sometimes you don't want
1303 <para>Enable—turns all voice announcements on and off</para>
1307 Test Voice—Plays a short message allowing you to verify
1308 that the audio system is working and the volume settings
1315 <title>Log Directory</title>
1317 AltosUI logs all telemetry data and saves all TeleMetrum flash
1318 data to this directory. This directory is also used as the
1319 staring point when selecting data files for display or export.
1322 Click on the directory name to bring up a directory choosing
1323 dialog, select a new directory and click 'Select Directory' to
1324 change where AltosUI reads and writes data files.
1328 <title>Callsign</title>
1330 This value is used in command packet mode and is transmitted
1331 in each packet sent from TeleDongle and received from
1332 TeleMetrum. It is not used in telemetry mode as that transmits
1333 packets only from TeleMetrum to TeleDongle. Configure this
1334 with the AltosUI operators call sign as needed to comply with
1335 your local radio regulations.
1339 <title>Font Size</title>
1341 Selects the set of fonts used in the flight monitor
1342 window. Choose between the small, medium and large sets.
1346 <title>Serial Debug</title>
1348 This causes all communication with a connected device to be
1349 dumped to the console from which AltosUI was started. If
1350 you've started it from an icon or menu entry, the output
1351 will simply be discarded. This mode can be useful to debug
1352 various serial communication issues.
1356 <title>Manage Frequencies</title>
1358 This brings up a dialog where you can configure the set of
1359 frequencies shown in the various frequency menus. You can
1360 add as many as you like, or even reconfigure the default
1361 set. Changing this list does not affect the frequency
1362 settings of any devices, it only changes the set of
1363 frequencies shown in the menus.
1368 <title>Flash Image</title>
1370 This reprograms any Altus Metrum device by using a TeleMetrum
1371 or TeleDongle as a programming dongle. Please read the
1372 directions for flashing devices in the Updating Device
1373 Firmware chapter below.
1376 Once you have the programmer and target devices connected,
1377 push the 'Flash Image' button. That will present a dialog box
1378 listing all of the connected devices. Carefully select the
1379 programmer device, not the device to be programmed.
1382 Next, select the image to flash to the device. These are named
1383 with the product name and firmware version. The file selector
1384 will start in the directory containing the firmware included
1385 with the AltosUI package. Navigate to the directory containing
1386 the desired firmware if it isn't there.
1389 Next, a small dialog containing the device serial number and
1390 RF calibration values should appear. If these values are
1391 incorrect (possibly due to a corrupted image in the device),
1392 enter the correct values here.
1395 Finally, a dialog containing a progress bar will follow the
1396 programming process.
1399 When programming is complete, the target device will
1400 reboot. Note that if the target device is connected via USB, you
1401 will have to unplug it and then plug it back in for the USB
1402 connection to reset so that you can communicate with the device
1407 <title>Fire Igniter</title>
1409 This activates the igniter circuits in TeleMetrum to help test
1410 recovery systems deployment. Because this command can operate
1411 over the Packet Command Link, you can prepare the rocket as
1412 for flight and then test the recovery system without needing
1413 to snake wires inside the air-frame.
1416 Selecting the 'Fire Igniter' button brings up the usual device
1417 selection dialog. Pick the desired TeleDongle or TeleMetrum
1418 device. This brings up another window which shows the current
1419 continuity test status for both apogee and main charges.
1422 Next, select the desired igniter to fire. This will enable the
1426 Select the 'Arm' button. This enables the 'Fire' button. The
1427 word 'Arm' is replaced by a countdown timer indicating that
1428 you have 10 seconds to press the 'Fire' button or the system
1429 will deactivate, at which point you start over again at
1430 selecting the desired igniter.
1434 <title>Scan Channels</title>
1436 This listens for telemetry packets on all of the configured
1437 frequencies, displaying information about each device it
1438 receives a packet from. You can select which of the three
1439 telemetry formats should be tried; by default, it only listens
1440 for the standard telemetry packets used in v1.0 and later
1445 <title>Load Maps</title>
1447 Before heading out to a new launch site, you can use this to
1448 load satellite images in case you don't have internet
1449 connectivity at the site. This loads a fairly large area
1450 around the launch site, which should cover any flight you're likely to make.
1453 There's a drop-down menu of launch sites we know about; if
1454 your favorites aren't there, please let us know the lat/lon
1455 and name of the site. The contents of this list are actually
1456 downloaded at run-time, so as new sites are sent in, they'll
1457 get automatically added to this list.
1460 If the launch site isn't in the list, you can manually enter the lat/lon values
1463 Clicking the 'Load Map' button will fetch images from Google
1464 Maps; note that Google limits how many images you can fetch at
1465 once, so if you load more than one launch site, you may get
1466 some gray areas in the map which indicate that Google is tired
1467 of sending data to you. Try again later.
1471 <title>Monitor Idle</title>
1473 This brings up a dialog similar to the Monitor Flight UI,
1474 except it works with the altimeter in "idle" mode by sending
1475 query commands to discover the current state rather than
1476 listening for telemetry packets.
1481 <title>Using Altus Metrum Products</title>
1483 <title>Being Legal</title>
1485 First off, in the US, you need an <ulink url="http://www.altusmetrum.org/Radio/">amateur radio license</ulink> or
1486 other authorization to legally operate the radio transmitters that are part
1491 <title>In the Rocket</title>
1493 In the rocket itself, you just need a <ulink url="http://www.altusmetrum.org/TeleMetrum/">TeleMetrum</ulink> or
1494 <ulink url="http://www.altusmetrum.org/TeleMini/">TeleMini</ulink> board and
1495 a Li-Po rechargeable battery. An 860mAh battery weighs less than a 9V
1496 alkaline battery, and will run a TeleMetrum for hours.
1497 A 110mAh battery weighs less than a triple A battery and will run a TeleMetrum for
1498 a few hours, or a TeleMini for much (much) longer.
1501 By default, we ship the altimeters with a simple wire antenna. If your
1502 electronics bay or the air-frame it resides within is made of carbon fiber,
1503 which is opaque to RF signals, you may choose to have an SMA connector
1504 installed so that you can run a coaxial cable to an antenna mounted
1505 elsewhere in the rocket.
1509 <title>On the Ground</title>
1511 To receive the data stream from the rocket, you need an antenna and short
1512 feed-line connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. The
1513 TeleDongle in turn plugs directly into the USB port on a notebook
1514 computer. Because TeleDongle looks like a simple serial port, your computer
1515 does not require special device drivers... just plug it in.
1518 The GUI tool, AltosUI, is written in Java and runs across
1519 Linux, Mac OS and Windows. There's also a suite of C tools
1520 for Linux which can perform most of the same tasks.
1523 After the flight, you can use the radio link to extract the more detailed data
1524 logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
1525 TeleMetrum board directly. Pulling out the data without having to open up
1526 the rocket is pretty cool! A USB cable is also how you charge the Li-Po
1527 battery, so you'll want one of those anyway... the same cable used by lots
1528 of digital cameras and other modern electronic stuff will work fine.
1531 If your TeleMetrum-equipped rocket lands out of sight, you may enjoy having a hand-held GPS
1532 receiver, so that you can put in a way-point for the last reported rocket
1533 position before touch-down. This makes looking for your rocket a lot like
1534 Geo-Caching... just go to the way-point and look around starting from there.
1537 You may also enjoy having a ham radio "HT" that covers the 70cm band... you
1538 can use that with your antenna to direction-find the rocket on the ground
1539 the same way you can use a Walston or Beeline tracker. This can be handy
1540 if the rocket is hiding in sage brush or a tree, or if the last GPS position
1541 doesn't get you close enough because the rocket dropped into a canyon, or
1542 the wind is blowing it across a dry lake bed, or something like that... Keith
1543 and Bdale both currently own and use the Yaesu VX-7R at launches.
1546 So, to recap, on the ground the hardware you'll need includes:
1547 <orderedlist inheritnum='inherit' numeration='arabic'>
1549 an antenna and feed-line
1558 optionally, a hand-held GPS receiver
1561 optionally, an HT or receiver covering 435 MHz
1566 The best hand-held commercial directional antennas we've found for radio
1567 direction finding rockets are from
1568 <ulink url="http://www.arrowantennas.com/" >
1571 The 440-3 and 440-5 are both good choices for finding a
1572 TeleMetrum- or TeleMini- equipped rocket when used with a suitable 70cm HT.
1576 <title>Data Analysis</title>
1578 Our software makes it easy to log the data from each flight, both the
1579 telemetry received during the flight itself, and the more
1580 complete data log recorded in the flash memory on the altimeter
1581 board. Once this data is on your computer, our post-flight tools make it
1582 easy to quickly get to the numbers everyone wants, like apogee altitude,
1583 max acceleration, and max velocity. You can also generate and view a
1584 standard set of plots showing the altitude, acceleration, and
1585 velocity of the rocket during flight. And you can even export a TeleMetrum data file
1586 usable with Google Maps and Google Earth for visualizing the flight path
1587 in two or three dimensions!
1590 Our ultimate goal is to emit a set of files for each flight that can be
1591 published as a web page per flight, or just viewed on your local disk with
1596 <title>Future Plans</title>
1598 In the future, we intend to offer "companion boards" for the rocket that will
1599 plug in to TeleMetrum to collect additional data, provide more pyro channels,
1600 and so forth. A reference design for a companion board will be documented
1601 soon, and will be compatible with open source Arduino programming tools.
1604 We are also working on the design of a hand-held ground terminal that will
1605 allow monitoring the rocket's status, collecting data during flight, and
1606 logging data after flight without the need for a notebook computer on the
1607 flight line. Particularly since it is so difficult to read most notebook
1608 screens in direct sunlight, we think this will be a great thing to have.
1611 Because all of our work is open, both the hardware designs and the software,
1612 if you have some great idea for an addition to the current Altus Metrum family,
1613 feel free to dive in and help! Or let us know what you'd like to see that
1614 we aren't already working on, and maybe we'll get excited about it too...
1619 <title>Altimeter Installation Recommendations</title>
1621 Building high-power rockets that fly safely is hard enough. Mix
1622 in some sophisticated electronics and a bunch of radio energy
1623 and oftentimes you find few perfect solutions. This chapter
1624 contains some suggestions about how to install Altus Metrum
1625 products into the rocket air-frame, including how to safely and
1626 reliably mix a variety of electronics into the same air-frame.
1629 <title>Mounting the Altimeter</title>
1631 The first consideration is to ensure that the altimeter is
1632 securely fastened to the air-frame. For TeleMetrum, we use
1633 nylon standoffs and nylon screws; they're good to at least 50G
1634 and cannot cause any electrical issues on the board. For
1635 TeleMini, we usually cut small pieces of 1/16" balsa to fit
1636 under the screw holes, and then take 2x56 nylon screws and
1637 screw them through the TeleMini mounting holes, through the
1638 balsa and into the underlying material.
1640 <orderedlist inheritnum='inherit' numeration='arabic'>
1642 Make sure TeleMetrum is aligned precisely along the axis of
1643 acceleration so that the accelerometer can accurately
1644 capture data during the flight.
1647 Watch for any metal touching components on the
1648 board. Shorting out connections on the bottom of the board
1649 can cause the altimeter to fail during flight.
1654 <title>Dealing with the Antenna</title>
1656 The antenna supplied is just a piece of solid, insulated,
1657 wire. If it gets damaged or broken, it can be easily
1658 replaced. It should be kept straight and not cut; bending or
1659 cutting it will change the resonant frequency and/or
1660 impedance, making it a less efficient radiator and thus
1661 reducing the range of the telemetry signal.
1664 Keeping metal away from the antenna will provide better range
1665 and a more even radiation pattern. In most rockets, it's not
1666 entirely possible to isolate the antenna from metal
1667 components; there are often bolts, all-thread and wires from other
1668 electronics to contend with. Just be aware that the more stuff
1669 like this around the antenna, the lower the range.
1672 Make sure the antenna is not inside a tube made or covered
1673 with conducting material. Carbon fiber is the most common
1674 culprit here -- CF is a good conductor and will effectively
1675 shield the antenna, dramatically reducing signal strength and
1676 range. Metallic flake paint is another effective shielding
1677 material which is to be avoided around any antennas.
1680 If the ebay is large enough, it can be convenient to simply
1681 mount the altimeter at one end and stretch the antenna out
1682 inside. Taping the antenna to the sled can keep it straight
1683 under acceleration. If there are metal rods, keep the
1684 antenna as far away as possible.
1687 For a shorter ebay, it's quite practical to have the antenna
1688 run through a bulkhead and into an adjacent bay. Drill a small
1689 hole in the bulkhead, pass the antenna wire through it and
1690 then seal it up with glue or clay. We've also used acrylic
1691 tubing to create a cavity for the antenna wire. This works a
1692 bit better in that the antenna is known to stay straight and
1693 not get folded by recovery components in the bay. Angle the
1694 tubing towards the side wall of the rocket and it ends up
1695 consuming very little space.
1698 If you need to place the antenna at a distance from the
1699 altimeter, you can replace the antenna with an edge-mounted
1700 SMA connector, and then run 50Ω coax from the board to the
1701 antenna. Building a remote antenna is beyond the scope of this
1706 <title>Preserving GPS Reception</title>
1708 The GPS antenna and receiver in TeleMetrum are highly
1709 sensitive and normally have no trouble tracking enough
1710 satellites to provide accurate position information for
1711 recovering the rocket. However, there are many ways to
1712 attenuate the GPS signal.
1713 <orderedlist inheritnum='inherit' numeration='arabic'>
1715 Conductive tubing or coatings. Carbon fiber and metal
1716 tubing, or metallic paint will all dramatically attenuate the
1717 GPS signal. We've never heard of anyone successfully
1718 receiving GPS from inside these materials.
1721 Metal components near the GPS patch antenna. These will
1722 de-tune the patch antenna, changing the resonant frequency
1723 away from the L1 carrier and reduce the effectiveness of the
1724 antenna. You can place as much stuff as you like beneath the
1725 antenna as that's covered with a ground plane. But, keep
1726 wires and metal out from above the patch antenna.
1732 <title>Radio Frequency Interference</title>
1734 Any altimeter will generate RFI; the digital circuits use
1735 high-frequency clocks that spray radio interference across a
1736 wide band. Altusmetrum altimeters generate intentional radio
1737 signals as well, increasing the amount of RF energy around the board.
1740 Rocketry altimeters also use precise sensors measuring air
1741 pressure and acceleration. Tiny changes in voltage can cause
1742 these sensor readings to vary by a huge amount. When the
1743 sensors start mis-reporting data, the altimeter can either
1744 fire the igniters at the wrong time, or not fire them at all.
1747 Voltages are induced when radio frequency energy is
1748 transmitted from one circuit to another. Here are things that
1749 increase the induced voltage and current:
1753 Keep wires from different circuits apart. Moving circuits
1754 further apart will reduce RFI.
1757 Avoid parallel wires from different circuits. The longer two
1758 wires run parallel to one another, the larger the amount of
1759 transferred energy. Cross wires at right angles to reduce
1763 Twist wires from the same circuits. Two wires the same
1764 distance from the transmitter will get the same amount of
1765 induced energy which will then cancel out. Any time you have
1766 a wire pair running together, twist the pair together to
1767 even out distances and reduce RFI. For altimeters, this
1768 includes battery leads, switch hookups and igniter
1772 Avoid resonant lengths. Know what frequencies are present
1773 in the environment and avoid having wire lengths near a
1774 natural resonant length. Altusmetrum products transmit on the
1775 70cm amateur band, so you should avoid lengths that are a
1776 simple ratio of that length; essentially any multiple of 1/4
1777 of the wavelength (17.5cm).
1782 <title>The Barometric Sensor</title>
1784 Altusmetrum altimeters measure altitude with a barometric
1785 sensor, essentially measuring the amount of air above the
1786 rocket to figure out how high it is. A large number of
1787 measurements are taken as the altimeter initializes itself to
1788 figure out the pad altitude. Subsequent measurements are then
1789 used to compute the height above the pad.
1792 To accurately measure atmospheric pressure, the ebay
1793 containing the altimeter must be vented outside the
1794 air-frame. The vent must be placed in a region of linear
1795 airflow, smooth and not in an area of increasing or decreasing
1799 The barometric sensor in the altimeter is quite sensitive to
1800 chemical damage from the products of APCP or BP combustion, so
1801 make sure the ebay is carefully sealed from any compartment
1802 which contains ejection charges or motors.
1806 <title>Ground Testing</title>
1808 The most important aspect of any installation is careful
1809 ground testing. Bringing an air-frame up to the LCO table which
1810 hasn't been ground tested can lead to delays or ejection
1811 charges firing on the pad, or, even worse, a recovery system
1815 Do a 'full systems' test that includes wiring up all igniters
1816 without any BP and turning on all of the electronics in flight
1817 mode. This will catch any mistakes in wiring and any residual
1818 RFI issues that might accidentally fire igniters at the wrong
1819 time. Let the air-frame sit for several minutes, checking for
1820 adequate telemetry signal strength and GPS lock.
1823 Ground test the ejection charges. Prepare the rocket for
1824 flight, loading ejection charges and igniters. Completely
1825 assemble the air-frame and then use the 'Fire Igniters'
1826 interface through a TeleDongle to command each charge to
1827 fire. Make sure the charge is sufficient to robustly separate
1828 the air-frame and deploy the recovery system.
1833 <title>Updating Device Firmware</title>
1835 The big conceptual thing to realize is that you have to use a
1836 TeleDongle as a programmer to update a TeleMetrum or TeleMini,
1837 and a TeleMetrum or other TeleDongle to program the TeleDongle
1838 Due to limited memory resources in the cc1111, we don't support
1839 programming directly over USB.
1842 You may wish to begin by ensuring you have current firmware images.
1843 These are distributed as part of the AltOS software bundle that
1844 also includes the AltosUI ground station program. Newer ground
1845 station versions typically work fine with older firmware versions,
1846 so you don't need to update your devices just to try out new
1847 software features. You can always download the most recent
1848 version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
1851 We recommend updating the altimeter first, before updating TeleDongle.
1854 <title>Updating TeleMetrum Firmware</title>
1855 <orderedlist inheritnum='inherit' numeration='arabic'>
1857 Find the 'programming cable' that you got as part of the starter
1858 kit, that has a red 8-pin MicroMaTch connector on one end and a
1859 red 4-pin MicroMaTch connector on the other end.
1862 Take the 2 screws out of the TeleDongle case to get access
1863 to the circuit board.
1866 Plug the 8-pin end of the programming cable to the
1867 matching connector on the TeleDongle, and the 4-pin end to the
1868 matching connector on the TeleMetrum.
1869 Note that each MicroMaTch connector has an alignment pin that
1870 goes through a hole in the PC board when you have the cable
1874 Attach a battery to the TeleMetrum board.
1877 Plug the TeleDongle into your computer's USB port, and power
1881 Run AltosUI, and select 'Flash Image' from the File menu.
1884 Pick the TeleDongle device from the list, identifying it as the
1888 Select the image you want put on the TeleMetrum, which should have a
1889 name in the form telemetrum-v1.1-1.0.0.ihx. It should be visible
1890 in the default directory, if not you may have to poke around
1891 your system to find it.
1894 Make sure the configuration parameters are reasonable
1895 looking. If the serial number and/or RF configuration
1896 values aren't right, you'll need to change them.
1899 Hit the 'OK' button and the software should proceed to flash
1900 the TeleMetrum with new firmware, showing a progress bar.
1903 Confirm that the TeleMetrum board seems to have updated OK, which you
1904 can do by plugging in to it over USB and using a terminal program
1905 to connect to the board and issue the 'v' command to check
1909 If something goes wrong, give it another try.
1914 <title>Updating TeleMini Firmware</title>
1915 <orderedlist inheritnum='inherit' numeration='arabic'>
1917 You'll need a special 'programming cable' to reprogram the
1918 TeleMini. It's available on the Altus Metrum web store, or
1919 you can make your own using an 8-pin MicroMaTch connector on
1920 one end and a set of four pins on the other.
1923 Take the 2 screws out of the TeleDongle case to get access
1924 to the circuit board.
1927 Plug the 8-pin end of the programming cable to the matching
1928 connector on the TeleDongle, and the 4-pins into the holes
1929 in the TeleMini circuit board. Note that the MicroMaTch
1930 connector has an alignment pin that goes through a hole in
1931 the PC board when you have the cable oriented correctly, and
1932 that pin 1 on the TeleMini board is marked with a square pad
1933 while the other pins have round pads.
1936 Attach a battery to the TeleMini board.
1939 Plug the TeleDongle into your computer's USB port, and power
1943 Run AltosUI, and select 'Flash Image' from the File menu.
1946 Pick the TeleDongle device from the list, identifying it as the
1950 Select the image you want put on the TeleMini, which should have a
1951 name in the form telemini-v1.0-1.0.0.ihx. It should be visible
1952 in the default directory, if not you may have to poke around
1953 your system to find it.
1956 Make sure the configuration parameters are reasonable
1957 looking. If the serial number and/or RF configuration
1958 values aren't right, you'll need to change them.
1961 Hit the 'OK' button and the software should proceed to flash
1962 the TeleMini with new firmware, showing a progress bar.
1965 Confirm that the TeleMini board seems to have updated OK, which you
1966 can do by configuring it over the radio link through the TeleDongle, or
1967 letting it come up in "flight" mode and listening for telemetry.
1970 If something goes wrong, give it another try.
1975 <title>Updating TeleDongle Firmware</title>
1977 Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
1978 firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
1980 <orderedlist inheritnum='inherit' numeration='arabic'>
1982 Find the 'programming cable' that you got as part of the starter
1983 kit, that has a red 8-pin MicroMaTch connector on one end and a
1984 red 4-pin MicroMaTch connector on the other end.
1987 Find the USB cable that you got as part of the starter kit, and
1988 plug the "mini" end in to the mating connector on TeleMetrum or TeleDongle.
1991 Take the 2 screws out of the TeleDongle case to get access
1992 to the circuit board.
1995 Plug the 8-pin end of the programming cable to the
1996 matching connector on the programmer, and the 4-pin end to the
1997 matching connector on the TeleDongle.
1998 Note that each MicroMaTch connector has an alignment pin that
1999 goes through a hole in the PC board when you have the cable
2003 Attach a battery to the TeleMetrum board if you're using one.
2006 Plug both the programmer and the TeleDongle into your computer's USB
2007 ports, and power up the programmer.
2010 Run AltosUI, and select 'Flash Image' from the File menu.
2013 Pick the programmer device from the list, identifying it as the
2017 Select the image you want put on the TeleDongle, which should have a
2018 name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
2019 in the default directory, if not you may have to poke around
2020 your system to find it.
2023 Make sure the configuration parameters are reasonable
2024 looking. If the serial number and/or RF configuration
2025 values aren't right, you'll need to change them. The TeleDongle
2026 serial number is on the "bottom" of the circuit board, and can
2027 usually be read through the translucent blue plastic case without
2028 needing to remove the board from the case.
2031 Hit the 'OK' button and the software should proceed to flash
2032 the TeleDongle with new firmware, showing a progress bar.
2035 Confirm that the TeleDongle board seems to have updated OK, which you
2036 can do by plugging in to it over USB and using a terminal program
2037 to connect to the board and issue the 'v' command to check
2038 the version, etc. Once you're happy, remove the programming cable
2039 and put the cover back on the TeleDongle.
2042 If something goes wrong, give it another try.
2046 Be careful removing the programming cable from the locking 8-pin
2047 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
2048 screwdriver or knife blade to gently pry the locking ears out
2049 slightly to extract the connector. We used a locking connector on
2050 TeleMetrum to help ensure that the cabling to companion boards
2051 used in a rocket don't ever come loose accidentally in flight.
2056 <title>Hardware Specifications</title>
2058 <title>TeleMetrum Specifications</title>
2062 Recording altimeter for model rocketry.
2067 Supports dual deployment (can fire 2 ejection charges).
2072 70cm ham-band transceiver for telemetry down-link.
2077 Barometric pressure sensor good to 45k feet MSL.
2082 1-axis high-g accelerometer for motor characterization, capable of
2083 +/- 50g using default part.
2088 On-board, integrated GPS receiver with 5Hz update rate capability.
2093 On-board 1 megabyte non-volatile memory for flight data storage.
2098 USB interface for battery charging, configuration, and data recovery.
2103 Fully integrated support for Li-Po rechargeable batteries.
2108 Uses Li-Po to fire e-matches, can be modified to support
2109 optional separate pyro battery if needed.
2114 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
2120 <title>TeleMini Specifications</title>
2124 Recording altimeter for model rocketry.
2129 Supports dual deployment (can fire 2 ejection charges).
2134 70cm ham-band transceiver for telemetry down-link.
2139 Barometric pressure sensor good to 45k feet MSL.
2144 On-board 5 kilobyte non-volatile memory for flight data storage.
2149 RF interface for battery charging, configuration, and data recovery.
2154 Support for Li-Po rechargeable batteries, using an external charger.
2159 Uses Li-Po to fire e-matches, can be modified to support
2160 optional separate pyro battery if needed.
2165 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube.
2174 TeleMetrum seems to shut off when disconnected from the
2175 computer. Make sure the battery is adequately charged. Remember the
2176 unit will pull more power than the USB port can deliver before the
2177 GPS enters "locked" mode. The battery charges best when TeleMetrum
2181 It's impossible to stop the TeleDongle when it's in "p" mode, I have
2182 to unplug the USB cable? Make sure you have tried to "escape out" of
2183 this mode. If this doesn't work the reboot procedure for the
2184 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
2185 outgoing buffer IF your "escape out" ('~~') does not work.
2186 At this point using either 'ao-view' (or possibly
2187 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
2191 The amber LED (on the TeleMetrum) lights up when both
2192 battery and USB are connected. Does this mean it's charging?
2193 Yes, the yellow LED indicates the charging at the 'regular' rate.
2194 If the led is out but the unit is still plugged into a USB port,
2195 then the battery is being charged at a 'trickle' rate.
2198 There are no "dit-dah-dah-dit" sound or lights like the manual mentions?
2199 That's the "pad" mode. Weak batteries might be the problem.
2200 It is also possible that the TeleMetrum is horizontal and the output
2201 is instead a "dit-dit" meaning 'idle'. For TeleMini, it's possible that
2202 it received a command packet which would have left it in "pad" mode.
2205 How do I save flight data?
2206 Live telemetry is written to file(s) whenever AltosUI is connected
2207 to the TeleDongle. The file area defaults to ~/TeleMetrum
2208 but is easily changed using the menus in AltosUI. The files that
2209 are written end in '.telem'. The after-flight
2210 data-dumped files will end in .eeprom and represent continuous data
2211 unlike the .telem files that are subject to losses
2212 along the RF data path.
2213 See the above instructions on what and how to save the eeprom stored
2214 data after physically retrieving your altimeter. Make sure to save
2215 the on-board data after each flight; while the TeleMetrum can store
2216 multiple flights, you never know when you'll lose the altimeter...
2220 <title>Notes for Older Software</title>
2223 Before AltosUI was written, using Altus Metrum devices required
2224 some finesse with the Linux command line. There was a limited
2225 GUI tool, ao-view, which provided functionality similar to the
2226 Monitor Flight window in AltosUI, but everything else was a
2227 fairly 80's experience. This appendix includes documentation for
2228 using that software.
2232 Both TeleMetrum and TeleDongle can be directly communicated
2233 with using USB ports. The first thing you should try after getting
2234 both units plugged into to your computer's USB port(s) is to run
2235 'ao-list' from a terminal-window to see what port-device-name each
2236 device has been assigned by the operating system.
2237 You will need this information to access the devices via their
2238 respective on-board firmware and data using other command line
2239 programs in the AltOS software suite.
2242 TeleMini can be communicated with through a TeleDongle device
2243 over the radio link. When first booted, TeleMini listens for a
2244 TeleDongle device and if it receives a packet, it goes into
2245 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be
2246 launched. The easiest way to get it talking is to start the
2247 communication link on the TeleDongle and the power up the
2251 To access the device's firmware for configuration you need a terminal
2252 program such as you would use to talk to a modem. The software
2253 authors prefer using the program 'cu' which comes from the UUCP package
2254 on most Unix-like systems such as Linux. An example command line for
2255 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
2256 indicated from running the
2257 ao-list program. Another reasonable terminal program for Linux is
2258 'cutecom'. The default 'escape'
2259 character used by CU (i.e. the character you use to
2260 issue commands to cu itself instead of sending the command as input
2261 to the connected device) is a '~'. You will need this for use in
2262 only two different ways during normal operations. First is to exit
2263 the program by sending a '~.' which is called a 'escape-disconnect'
2264 and allows you to close-out from 'cu'. The
2265 second use will be outlined later.
2268 All of the Altus Metrum devices share the concept of a two level
2269 command set in their firmware.
2270 The first layer has several single letter commands. Once
2271 you are using 'cu' (or 'cutecom') sending (typing) a '?'
2272 returns a full list of these
2273 commands. The second level are configuration sub-commands accessed
2274 using the 'c' command, for
2275 instance typing 'c?' will give you this second level of commands
2276 (all of which require the
2277 letter 'c' to access). Please note that most configuration options
2278 are stored only in Flash memory; TeleDongle doesn't provide any storage
2279 for these options and so they'll all be lost when you unplug it.
2282 Try setting these configuration ('c' or second level menu) values. A good
2283 place to start is by setting your call sign. By default, the boards
2284 use 'N0CALL' which is cute, but not exactly legal!
2285 Spend a few minutes getting comfortable with the units, their
2286 firmware, and 'cu' (or possibly 'cutecom').
2287 For instance, try to send
2288 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
2289 Verify you can connect and disconnect from the units while in your
2290 terminal program by sending the escape-disconnect mentioned above.
2293 Note that the 'reboot' command, which is very useful on the altimeters,
2294 will likely just cause problems with the dongle. The *correct* way
2295 to reset the dongle is just to unplug and re-plug it.
2298 A fun thing to do at the launch site and something you can do while
2299 learning how to use these units is to play with the radio link access
2300 between an altimeter and the TeleDongle. Be aware that you *must* create
2301 some physical separation between the devices, otherwise the link will
2302 not function due to signal overload in the receivers in each device.
2305 Now might be a good time to take a break and read the rest of this
2306 manual, particularly about the two "modes" that the altimeters
2307 can be placed in. TeleMetrum uses the position of the device when booting
2308 up will determine whether the unit is in "pad" or "idle" mode. TeleMini
2309 enters "idle" mode when it receives a command packet within the first 5 seconds
2310 of being powered up, otherwise it enters "pad" mode.
2313 You can access an altimeter in idle mode from the TeleDongle's USB
2314 connection using the radio link
2315 by issuing a 'p' command to the TeleDongle. Practice connecting and
2316 disconnecting ('~~' while using 'cu') from the altimeter. If
2317 you cannot escape out of the "p" command, (by using a '~~' when in
2318 CU) then it is likely that your kernel has issues. Try a newer version.
2321 Using this radio link allows you to configure the altimeter, test
2322 fire e-matches and igniters from the flight line, check pyro-match
2323 continuity and so forth. You can leave the unit turned on while it
2324 is in 'idle mode' and then place the
2325 rocket vertically on the launch pad, walk away and then issue a
2326 reboot command. The altimeter will reboot and start sending data
2327 having changed to the "pad" mode. If the TeleDongle is not receiving
2328 this data, you can disconnect 'cu' from the TeleDongle using the
2329 procedures mentioned above and THEN connect to the TeleDongle from
2330 inside 'ao-view'. If this doesn't work, disconnect from the
2331 TeleDongle, unplug it, and try again after plugging it back in.
2334 In order to reduce the chance of accidental firing of pyrotechnic
2335 charges, the command to fire a charge is intentionally somewhat
2336 difficult to type, and the built-in help is slightly cryptic to
2337 prevent accidental echoing of characters from the help text back at
2338 the board from firing a charge. The command to fire the apogee
2339 drogue charge is 'i DoIt drogue' and the command to fire the main
2340 charge is 'i DoIt main'.
2343 On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
2344 and 'ao-view' will both auditorily announce and visually indicate
2346 Now you can launch knowing that you have a good data path and
2347 good satellite lock for flight data and recovery. Remember
2348 you MUST tell ao-view to connect to the TeleDongle explicitly in
2349 order for ao-view to be able to receive data.
2352 The altimeters provide RDF (radio direction finding) tones on
2353 the pad, during descent and after landing. These can be used to
2354 locate the rocket using a directional antenna; the signal
2355 strength providing an indication of the direction from receiver to rocket.
2358 TeleMetrum also provides GPS trekking data, which can further simplify
2359 locating the rocket once it has landed. (The last good GPS data
2360 received before touch-down will be on the data screen of 'ao-view'.)
2363 Once you have recovered the rocket you can download the eeprom
2364 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
2365 either a USB cable or over the radio link using TeleDongle.
2366 And by following the man page for 'ao-postflight' you can create
2367 various data output reports, graphs, and even KML data to see the
2368 flight trajectory in Google-earth. (Moving the viewing angle making
2369 sure to connect the yellow lines while in Google-earth is the proper
2373 As for ao-view.... some things are in the menu but don't do anything
2374 very useful. The developers have stopped working on ao-view to focus
2375 on a new, cross-platform ground station program. So ao-view may or
2376 may not be updated in the future. Mostly you just use
2377 the Log and Device menus. It has a wonderful display of the incoming
2378 flight data and I am sure you will enjoy what it has to say to you
2379 once you enable the voice output!
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