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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>10 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 (TeleMetrum/TeleMini and
44 TeleDongle) must be updated or communications will fail.
48 <revnumber>0.9</revnumber>
49 <date>18 January 2011</date>
51 Updated for software version 0.9. Note that 0.9 represents a
52 telemetry format change, meaning both ends of a link (TeleMetrum and
53 TeleDongle) must be updated or communications will fail.
57 <revnumber>0.8</revnumber>
58 <date>24 November 2010</date>
59 <revremark>Updated for software version 0.8 </revremark>
65 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing "The
66 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
67 Kit" which has turned into the Getting Started chapter in this
68 book. Bob was one of our first customers for a production
69 TeleMetrum, and the enthusiasm that led to his contribution of
70 this section is immensely gratifying and highly appreciated!
73 And thanks to Anthony (AJ) Towns for contributing the
74 AltosUI graphing and site map code and documentation. Free
75 software means that our customers and friends can become our
76 collaborators, and we certainly appreciate this level of
80 Have fun using these products, and we hope to meet all of you
81 out on the rocket flight line somewhere.
84 NAR #87103, TRA #12201
87 NAR #88757, TRA #12200
92 <title>Introduction and Overview</title>
94 Welcome to the Altus Metrum community! Our circuits and software reflect
95 our passion for both hobby rocketry and Free Software. We hope their
96 capabilities and performance will delight you in every way, but by
97 releasing all of our hardware and software designs under open licenses,
98 we also hope to empower you to take as active a role in our collective
102 The first device created for our community was TeleMetrum, a dual
103 deploy altimeter with fully integrated GPS and radio telemetry
104 as standard features, and a "companion interface" that will
105 support optional capabilities in the future.
108 The newest device is TeleMini, a dual deploy altimeter with
109 radio telemetry and radio direction finding. This device is only
110 13mm by 38mm (½ inch by 1½ inches) and can fit easily in an 18mm air-frame.
113 Complementing TeleMetrum and TeleMini is TeleDongle, a USB to RF interface for
114 communicating with the altimeters. Combined with your choice of antenna and
115 notebook computer, TeleDongle and our associated user interface software
116 form a complete ground station capable of logging and displaying in-flight
117 telemetry, aiding rocket recovery, then processing and archiving flight
118 data for analysis and review.
121 More products will be added to the Altus Metrum family over time, and
122 we currently envision that this will be a single, comprehensive manual
123 for the entire product family.
127 <title>Getting Started</title>
129 The first thing to do after you check the inventory of parts in your
130 "starter kit" is to charge the battery.
133 The TeleMetrum battery can be charged by plugging it into the
134 corresponding socket of the TeleMetrum and then using the USB A to
136 cable to plug the TeleMetrum into your computer's USB socket. The
137 TeleMetrum circuitry will charge the battery whenever it is plugged
138 in, because the TeleMetrum's on-off switch does NOT control the
142 When the GPS chip is initially searching for
143 satellites, TeleMetrum will consume more current than it can pull
144 from the USB port, so the battery must be attached in order to get
145 satellite lock. Once GPS is locked, the current consumption goes back
146 down enough to enable charging while
147 running. So it's a good idea to fully charge the battery as your
148 first item of business so there is no issue getting and maintaining
149 satellite lock. The yellow charge indicator led will go out when the
150 battery is nearly full and the charger goes to trickle charge. It
151 can take several hours to fully recharge a deeply discharged battery.
154 The TeleMini battery can be charged by disconnecting it from the
155 TeleMini board and plugging it into a standalone battery charger
156 board, and connecting that via a USB cable to a laptop or other USB
160 The other active device in the starter kit is the TeleDongle USB to
161 RF interface. If you plug it in to your Mac or Linux computer it should
162 "just work", showing up as a serial port device. Windows systems need
163 driver information that is part of the AltOS download to know that the
164 existing USB modem driver will work. We therefore recommend installing
165 our software before plugging in TeleDongle if you are using a Windows
166 computer. If you are using Linux and are having problems, try moving
167 to a fresher kernel (2.6.33 or newer), as the USB serial driver had
168 ugly bugs in some earlier versions.
171 Next you should obtain and install the AltOS utilities. These include
172 the AltosUI ground station program, current firmware images for
173 TeleMetrum, TeleMini and TeleDongle, and a number of standalone utilities that
174 are rarely needed. Pre-built binary packages are available for Debian
175 Linux, Microsoft Windows, and recent MacOSX versions. Full source code
176 and build instructions for some other Linux variants are also available.
177 The latest version may always be downloaded from
178 <ulink url="http://altusmetrum.org/AltOS"/>.
182 <title>Handling Precautions</title>
184 All Altus Metrum products are sophisticated electronic devices.
185 When handled gently and properly installed in an air-frame, they
186 will deliver impressive results. However, like all electronic
187 devices, there are some precautions you must take.
190 The Lithium Polymer rechargeable batteries have an
191 extraordinary power density. This is great because we can fly with
192 much less battery mass than if we used alkaline batteries or previous
193 generation rechargeable batteries... but if they are punctured
194 or their leads are allowed to short, they can and will release their
196 Thus we recommend that you take some care when handling our batteries
197 and consider giving them some extra protection in your air-frame. We
198 often wrap them in suitable scraps of closed-cell packing foam before
199 strapping them down, for example.
202 The barometric sensors used on both TeleMetrum and TeleMini are
203 sensitive to sunlight. In normal TeleMetrum mounting situations, it
204 and all of the other surface mount components
205 are "down" towards whatever the underlying mounting surface is, so
206 this is not normally a problem. Please consider this, though, when
207 designing an installation, for example, in an air-frame with a
208 see-through plastic payload bay. It is particularly important to
209 consider this with TeleMini, both because the baro sensor is on the
210 "top" of the board, and because many model rockets with payload bays
211 use clear plastic for the payload bay! Replacing these with an opaque
212 cardboard tube, painting them, or wrapping them with a layer of masking
213 tape are all reasonable approaches to keep the sensor out of direct
217 The barometric sensor sampling port must be able to "breathe",
218 both by not being covered by foam or tape or other materials that might
219 directly block the hole on the top of the sensor, and also by having a
220 suitable static vent to outside air.
223 As with all other rocketry electronics, Altus Metrum altimeters must
224 be protected from exposure to corrosive motor exhaust and ejection
229 <title>Hardware Overview</title>
231 TeleMetrum is a 1 inch by 2.75 inch circuit board. It was designed to
232 fit inside coupler for 29mm air-frame tubing, but using it in a tube that
233 small in diameter may require some creativity in mounting and wiring
234 to succeed! The presence of an accelerometer means TeleMetrum should
235 be aligned along the flight axis of the airframe, and by default the 1/4
236 wave UHF wire antenna should be on the nose-cone end of the board. The
237 antenna wire is about 7 inches long, and wiring for a power switch and
238 the e-matches for apogee and main ejection charges depart from the
239 fin can end of the board, meaning an ideal "simple" avionics
240 bay for TeleMetrum should have at least 10 inches of interior length.
243 TeleMini is a 0.5 inch by 1.5 inch circuit board. It was designed to
244 fit inside an 18mm air-frame tube, but using it in a tube that
245 small in diameter may require some creativity in mounting and wiring
246 to succeed! Since there is no accelerometer, TeleMini can be mounted
247 in any convenient orientation. The default 1/4
248 wave UHF wire antenna attached to the center of one end of
249 the board is about 7 inches long, and wiring for a power switch and
250 the e-matches for apogee and main ejection charges depart from the
251 other end of the board, meaning an ideal "simple" avionics
252 bay for TeleMini should have at least 9 inches of interior length.
255 A typical TeleMetrum or TeleMini installation involves attaching
256 only a suitable Lithium Polymer battery, a single pole switch for
257 power on/off, and two pairs of wires connecting e-matches for the
258 apogee and main ejection charges.
261 By default, we use the unregulated output of the Li-Po battery directly
262 to fire ejection charges. This works marvelously with standard
263 low-current e-matches like the J-Tek from MJG Technologies, and with
264 Quest Q2G2 igniters. However, if you want or need to use a separate
265 pyro battery, check out the "External Pyro Battery" section in this
266 manual for instructions on how to wire that up. The altimeters are
267 designed to work with an external pyro battery of no more than 15 volts.
270 Ejection charges are wired directly to the screw terminal block
271 at the aft end of the altimeter. You'll need a very small straight
272 blade screwdriver for these screws, such as you might find in a
273 jeweler's screwdriver set.
276 TeleMetrum also uses the screw terminal block for the power
277 switch leads. On TeleMini, the power switch leads are soldered
278 directly to the board and can be connected directly to a switch.
281 For most air-frames, the integrated antennas are more than
282 adequate. However, if you are installing in a carbon-fiber or
283 metal electronics bay which is opaque to RF signals, you may need to
284 use off-board external antennas instead. In this case, you can
285 order an altimeter with an SMA connector for the UHF antenna
286 connection, and, on TeleMetrum, you can unplug the integrated GPS
287 antenna and select an appropriate off-board GPS antenna with
288 cable terminating in a U.FL connector.
292 <title>System Operation</title>
294 <title>Firmware Modes </title>
296 The AltOS firmware build for the altimeters has two
297 fundamental modes, "idle" and "flight". Which of these modes
298 the firmware operates in is determined at start up time. For
299 TeleMetrum, the mode is controlled by the orientation of the
300 rocket (well, actually the board, of course...) at the time
301 power is switched on. If the rocket is "nose up", then
302 TeleMetrum assumes it's on a rail or rod being prepared for
303 launch, so the firmware chooses flight mode. However, if the
304 rocket is more or less horizontal, the firmware instead enters
305 idle mode. Since TeleMini doesn't have an accelerometer we can
306 use to determine orientation, "idle" mode is selected when the
307 board receives a command packet within the first five seconds
308 of operation; if no packet is received, the board enters
312 At power on, you will hear three beeps or see three flashes
313 ("S" in Morse code for start up) and then a pause while
314 the altimeter completes initialization and self test, and decides
315 which mode to enter next.
318 In flight or "pad" mode, the altimeter engages the flight
319 state machine, goes into transmit-only mode on the RF link
320 sending telemetry, and waits for launch to be detected.
321 Flight mode is indicated by an "di-dah-dah-dit" ("P" for pad)
322 on the beeper or lights, followed by beeps or flashes
323 indicating the state of the pyrotechnic igniter continuity.
324 One beep/flash indicates apogee continuity, two beeps/flashes
325 indicate main continuity, three beeps/flashes indicate both
326 apogee and main continuity, and one longer "brap" sound or
327 rapidly alternating lights indicates no continuity. For a
328 dual deploy flight, make sure you're getting three beeps or
329 flashes before launching! For apogee-only or motor eject
330 flights, do what makes sense.
333 If idle mode is entered, you will hear an audible "di-dit" or see
334 two short flashes ("I" for idle), and the flight state machine is
335 disengaged, thus no ejection charges will fire. The altimeters also
336 listen on the RF link when in idle mode for requests sent via
337 TeleDongle. Commands can be issued to a TeleMetrum in idle mode
339 USB or the RF link equivalently. TeleMini only has the RF link.
340 Idle mode is useful for configuring the altimeter, for extracting data
341 from the on-board storage chip after flight, and for ground testing
345 One "neat trick" of particular value when TeleMetrum is used with
346 very large air-frames, is that you can power the board up while the
347 rocket is horizontal, such that it comes up in idle mode. Then you can
348 raise the air-frame to launch position, and issue a 'reset' command
349 via TeleDongle over the RF link to cause the altimeter to reboot and
350 come up in flight mode. This is much safer than standing on the top
351 step of a rickety step-ladder or hanging off the side of a launch
352 tower with a screw-driver trying to turn on your avionics before
359 TeleMetrum includes a complete GPS receiver. A complete explanation
360 of how GPS works is beyond the scope of this manual, but the bottom
361 line is that the TeleMetrum GPS receiver needs to lock onto at least
362 four satellites to obtain a solid 3 dimensional position fix and know
366 TeleMetrum provides backup power to the GPS chip any time a
367 battery is connected. This allows the receiver to "warm start" on
368 the launch rail much faster than if every power-on were a GPS
369 "cold start". In typical operations, powering up TeleMetrum
370 on the flight line in idle mode while performing final air-frame
371 preparation will be sufficient to allow the GPS receiver to cold
372 start and acquire lock. Then the board can be powered down during
373 RSO review and installation on a launch rod or rail. When the board
374 is turned back on, the GPS system should lock very quickly, typically
375 long before igniter installation and return to the flight line are
380 <title>Packet Command Mode</title>
381 <subtitle>Controlling An Altimeter Over The Radio Link</subtitle>
383 One of the unique features of the Altus Metrum environment is
384 the ability to create a two way command link between TeleDongle
385 and an altimeter using the digital radio transceivers built into
386 each device. This allows you to interact with the altimeter from
387 afar, as if it were directly connected to the computer.
390 Any operation which can be performed with TeleMetrum can
391 either be done with TeleMetrum directly connected to the
392 computer via the USB cable, or through the packet
393 link. TeleMini doesn't provide a USB connector and so it is
394 always controlled through the packet link. Select the
395 appropriate TeleDongle device when the list of devices is
396 presented and AltosUI will use packet command mode.
399 One oddity in the current interface is how AltosUI selects the
400 frequency for packet mode communications. Instead of providing
401 an interface to specifically configure the frequency, it uses
402 whatever frequency was most recently selected for the target
403 TeleDongle device in Monitor Flight mode. If you haven't ever
404 used that mode with the TeleDongle in question, select the
405 Monitor Flight button from the top level UI, pick the
406 appropriate TeleDongle device. Once the flight monitoring
407 window is open, select the desired frequency and then close it
408 down again. All Packet Command Mode operations will now use
414 Save Flight Data—Recover flight data from the rocket without
420 Configure altimeter apogee delays or main deploy heights
421 to respond to changing launch conditions. You can also
422 'reboot' the altimeter. Use this to remotely enable the
423 flight computer by turning TeleMetrum on in "idle" mode,
424 then once the air-frame is oriented for launch, you can
425 reboot the altimeter and have it restart in pad mode
426 without having to climb the scary ladder.
431 Fire Igniters—Test your deployment charges without snaking
432 wires out through holes in the air-frame. Simply assembly the
433 rocket as if for flight with the apogee and main charges
434 loaded, then remotely command the altimeter to fire the
440 Packet command mode uses the same RF frequencies as telemetry
441 mode. Configure the desired TeleDongle frequency using the
442 flight monitor window frequency selector and then close that
443 window before performing the desired operation.
446 TeleMetrum only enables packet command mode in 'idle' mode, so
447 make sure you have TeleMetrum lying horizontally when you turn
448 it on. Otherwise, TeleMetrum will start in 'pad' mode ready for
449 flight and will not be listening for command packets from TeleDongle.
452 TeleMini listens for a command packet for five seconds after
453 first being turned on, if it doesn't hear anything, it enters
454 'pad' mode, ready for flight and will no longer listen for
455 command packets. The easiest way to connect to TeleMini is to
456 initiate the command and select the TeleDongle device. At this
457 point, the TeleDongle will be attempting to communicate with
458 the TeleMini. Now turn TeleMini on, and it should immediately
459 start communicating with the TeleDongle and the desired
460 operation can be performed.
463 When packet command mode is enabled, you can monitor the link
464 by watching the lights on the
465 devices. The red LED will flash each time they
466 transmit a packet while the green LED will light up
467 on TeleDongle while it is waiting to receive a packet from
472 <title>Ground Testing </title>
474 An important aspect of preparing a rocket using electronic deployment
475 for flight is ground testing the recovery system. Thanks
476 to the bi-directional RF link central to the Altus Metrum system,
477 this can be accomplished in a TeleMetrum or TeleMini equipped rocket
478 with less work than you may be accustomed to with other systems. It
482 Just prep the rocket for flight, then power up the altimeter
483 in "idle" mode (placing air-frame horizontal for TeleMetrum or
484 selected the Configure Altimeter tab for TeleMini). This will cause
485 the firmware to go into "idle" mode, in which the normal flight
486 state machine is disabled and charges will not fire without
487 manual command. You can now command the altimeter to fire the apogee
488 or main charges from a safe distance using your computer and
489 TeleDongle and the Fire Igniter tab to complete ejection testing.
493 <title>Radio Link </title>
495 The chip our boards are based on incorporates an RF transceiver, but
496 it's not a full duplex system... each end can only be transmitting or
497 receiving at any given moment. So we had to decide how to manage the
501 By design, the altimeter firmware listens for an RF connection when
502 it's in "idle mode", which
503 allows us to use the RF link to configure the rocket, do things like
504 ejection tests, and extract data after a flight without having to
505 crack open the air-frame. However, when the board is in "flight
506 mode", the altimeter only
507 transmits and doesn't listen at all. That's because we want to put
508 ultimate priority on event detection and getting telemetry out of
509 the rocket and out over
510 the RF link in case the rocket crashes and we aren't able to extract
514 We don't use a 'normal packet radio' mode because they're just too
515 inefficient. The GFSK modulation we use is just FSK with the
516 base-band pulses passed through a
517 Gaussian filter before they go into the modulator to limit the
518 transmitted bandwidth. When combined with the hardware forward error
519 correction support in the cc1111 chip, this allows us to have a very
520 robust 38.4 kilobit data link with only 10 milliwatts of transmit power,
521 a whip antenna in the rocket, and a hand-held Yagi on the ground. We've
522 had flights to above 21k feet AGL with good reception, and calculations
523 suggest we should be good to well over 40k feet AGL with a 5-element yagi on
524 the ground. We hope to fly boards to higher altitudes soon, and would
525 of course appreciate customer feedback on performance in higher
530 <title>Configurable Parameters</title>
532 Configuring an Altus Metrum altimeter for flight is very
533 simple. Through the use of a Kalman filter, there is no need
534 to set a "mach delay" . The few configurable parameters can
535 all be set using a simple terminal program over the USB port
536 or RF link via TeleDongle.
539 <title>Radio Frequencies</title>
541 The Altus Metrum boards support frequencies in the 70cm
542 band. By default, the configuration interface provides a
543 list of 10 common frequencies -- 100kHz channels starting at
544 434.550MHz. However, you can configure the firmware to use
545 any 50kHz multiple within the 70cm band. At any given
546 launch, we highly recommend coordinating who will use each
547 frequency and when to avoid interference. And of course, both
548 altimeter and TeleDongle must be configured to the same
549 frequency to successfully communicate with each other.
552 To set the radio frequency, use the 'c R' command to specify the
553 radio transceiver configuration parameter. This parameter is computed
554 using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
555 the standard calibration reference frequency, 'S', (normally 434.550MHz):
559 Round the result to the nearest integer value.
560 As with all 'c' sub-commands, follow this with a 'c w' to write the
561 change to the parameter block in the on-board flash on
562 your altimeter board if you want the change to stay in place across reboots.
566 <title>Apogee Delay</title>
568 Apogee delay is the number of seconds after the altimeter detects flight
569 apogee that the drogue charge should be fired. In most cases, this
570 should be left at the default of 0. However, if you are flying
571 redundant electronics such as for an L3 certification, you may wish
572 to set one of your altimeters to a positive delay so that both
573 primary and backup pyrotechnic charges do not fire simultaneously.
576 To set the apogee delay, use the 'c d' command.
577 As with all 'c' sub-commands, follow this with a 'c w' to write the
578 change to the parameter block in the on-board DataFlash chip.
581 Please note that the Altus Metrum apogee detection algorithm
582 fires exactly at apogee. If you are also flying an
583 altimeter like the PerfectFlite MAWD, which only supports
584 selecting 0 or 1 seconds of apogee delay, you may wish to
585 set the MAWD to 0 seconds delay and set the TeleMetrum to
586 fire your backup 2 or 3 seconds later to avoid any chance of
587 both charges firing simultaneously. We've flown several
588 air-frames this way quite happily, including Keith's
593 <title>Main Deployment Altitude</title>
595 By default, the altimeter will fire the main deployment charge at an
596 elevation of 250 meters (about 820 feet) above ground. We think this
597 is a good elevation for most air-frames, but feel free to change this
598 to suit. In particular, if you are flying two altimeters, you may
600 deployment elevation for the backup altimeter to be something lower
601 than the primary so that both pyrotechnic charges don't fire
605 To set the main deployment altitude, use the 'c m' command.
606 As with all 'c' sub-commands, follow this with a 'c w' to write the
607 change to the parameter block in the on-board DataFlash chip.
612 <title>Calibration</title>
614 There are only two calibrations required for a TeleMetrum board, and
615 only one for TeleDongle and TeleMini.
618 <title>Radio Frequency</title>
620 The radio frequency is synthesized from a clock based on the 48 MHz
621 crystal on the board. The actual frequency of this oscillator must be
622 measured to generate a calibration constant. While our GFSK modulation
623 bandwidth is wide enough to allow boards to communicate even when
624 their oscillators are not on exactly the same frequency, performance
625 is best when they are closely matched.
626 Radio frequency calibration requires a calibrated frequency counter.
627 Fortunately, once set, the variation in frequency due to aging and
628 temperature changes is small enough that re-calibration by customers
629 should generally not be required.
632 To calibrate the radio frequency, connect the UHF antenna port to a
633 frequency counter, set the board to 434.550MHz, and use the 'C'
634 command to generate a CW carrier. Wait for the transmitter temperature
635 to stabilize and the frequency to settle down.
636 Then, divide 434.550 MHz by the
637 measured frequency and multiply by the current radio cal value show
638 in the 'c s' command. For an unprogrammed board, the default value
639 is 1186611. Take the resulting integer and program it using the 'c f'
640 command. Testing with the 'C' command again should show a carrier
641 within a few tens of Hertz of the intended frequency.
642 As with all 'c' sub-commands, follow this with a 'c w' to write the
643 change to the parameter block in the on-board DataFlash chip.
646 when the radio calibration value is changed, the radio
647 frequency value is reset to the same value, so you'll need
648 to recompute and reset the radio frequency value using the
649 new radio calibration value.
653 <title>TeleMetrum Accelerometer</title>
655 The TeleMetrum accelerometer we use has its own 5 volt power supply and
656 the output must be passed through a resistive voltage divider to match
657 the input of our 3.3 volt ADC. This means that unlike the barometric
658 sensor, the output of the acceleration sensor is not ratio-metric to
659 the ADC converter, and calibration is required. We also support the
660 use of any of several accelerometers from a Freescale family that
661 includes at least +/- 40g, 50g, 100g, and 200g parts. Using gravity,
662 a simple 2-point calibration yields acceptable results capturing both
663 the different sensitivities and ranges of the different accelerometer
664 parts and any variation in power supply voltages or resistor values
665 in the divider network.
668 To calibrate the acceleration sensor, use the 'c a 0' command. You
669 will be prompted to orient the board vertically with the UHF antenna
670 up and press a key, then to orient the board vertically with the
671 UHF antenna down and press a key.
672 As with all 'c' sub-commands, follow this with a 'c w' to write the
673 change to the parameter block in the on-board DataFlash chip.
676 The +1g and -1g calibration points are included in each telemetry
677 frame and are part of the header extracted by ao-dumplog after flight.
678 Note that we always store and return raw ADC samples for each
679 sensor... nothing is permanently "lost" or "damaged" if the
683 In the unlikely event an accel cal that goes badly, it is possible
684 that TeleMetrum may always come up in 'pad mode' and as such not be
685 listening to either the USB or radio interfaces. If that happens,
686 there is a special hook in the firmware to force the board back
687 in to 'idle mode' so you can re-do the cal. To use this hook, you
688 just need to ground the SPI clock pin at power-on. This pin is
689 available as pin 2 on the 8-pin companion connector, and pin 1 is
690 ground. So either carefully install a fine-gauge wire jumper
691 between the two pins closest to the index hole end of the 8-pin
692 connector, or plug in the programming cable to the 8-pin connector
693 and use a small screwdriver or similar to short the two pins closest
694 to the index post on the 4-pin end of the programming cable, and
695 power up the board. It should come up in 'idle mode' (two beeps).
700 <title>Updating Device Firmware</title>
702 The big conceptual thing to realize is that you have to use a
703 TeleDongle as a programmer to update a TeleMetrum or TeleMini,
704 and a TeleMetrum or other TeleDongle to program the TeleDongle
705 Due to limited memory resources in the cc1111, we don't support
706 programming directly over USB.
709 You may wish to begin by ensuring you have current firmware images.
710 These are distributed as part of the AltOS software bundle that
711 also includes the AltosUI ground station program. Newer ground
712 station versions typically work fine with older firmware versions,
713 so you don't need to update your devices just to try out new
714 software features. You can always download the most recent
715 version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
718 We recommend updating the altimeter first, before updating TeleDongle.
721 <title>Updating TeleMetrum Firmware</title>
722 <orderedlist inheritnum='inherit' numeration='arabic'>
724 Find the 'programming cable' that you got as part of the starter
725 kit, that has a red 8-pin MicroMaTch connector on one end and a
726 red 4-pin MicroMaTch connector on the other end.
729 Take the 2 screws out of the TeleDongle case to get access
730 to the circuit board.
733 Plug the 8-pin end of the programming cable to the
734 matching connector on the TeleDongle, and the 4-pin end to the
735 matching connector on the TeleMetrum.
736 Note that each MicroMaTch connector has an alignment pin that
737 goes through a hole in the PC board when you have the cable
741 Attach a battery to the TeleMetrum board.
744 Plug the TeleDongle into your computer's USB port, and power
748 Run AltosUI, and select 'Flash Image' from the File menu.
751 Pick the TeleDongle device from the list, identifying it as the
755 Select the image you want put on the TeleMetrum, which should have a
756 name in the form telemetrum-v1.1-1.0.0.ihx. It should be visible
757 in the default directory, if not you may have to poke around
758 your system to find it.
761 Make sure the configuration parameters are reasonable
762 looking. If the serial number and/or RF configuration
763 values aren't right, you'll need to change them.
766 Hit the 'OK' button and the software should proceed to flash
767 the TeleMetrum with new firmware, showing a progress bar.
770 Confirm that the TeleMetrum board seems to have updated OK, which you
771 can do by plugging in to it over USB and using a terminal program
772 to connect to the board and issue the 'v' command to check
776 If something goes wrong, give it another try.
781 <title>Updating TeleMini Firmware</title>
782 <orderedlist inheritnum='inherit' numeration='arabic'>
784 You'll need a special 'programming cable' to reprogram the
785 TeleMini. It's available on the Altus Metrum web store, or
786 you can make your own using an 8-pin MicroMaTch connector on
787 one end and a set of four pins on the other.
790 Take the 2 screws out of the TeleDongle case to get access
791 to the circuit board.
794 Plug the 8-pin end of the programming cable to the matching
795 connector on the TeleDongle, and the 4-pins into the holes
796 in the TeleMini circuit board. Note that the MicroMaTch
797 connector has an alignment pin that goes through a hole in
798 the PC board when you have the cable oriented correctly, and
799 that pin 1 on the TeleMini board is marked with a square pad
800 while the other pins have round pads.
803 Attach a battery to the TeleMini board.
806 Plug the TeleDongle into your computer's USB port, and power
810 Run AltosUI, and select 'Flash Image' from the File menu.
813 Pick the TeleDongle device from the list, identifying it as the
817 Select the image you want put on the TeleMini, which should have a
818 name in the form telemini-v1.0-1.0.0.ihx. It should be visible
819 in the default directory, if not you may have to poke around
820 your system to find it.
823 Make sure the configuration parameters are reasonable
824 looking. If the serial number and/or RF configuration
825 values aren't right, you'll need to change them.
828 Hit the 'OK' button and the software should proceed to flash
829 the TeleMini with new firmware, showing a progress bar.
832 Confirm that the TeleMini board seems to have updated OK, which you
833 can do by configuring it over the RF link through the TeleDongle, or
834 letting it come up in "flight" mode and listening for telemetry.
837 If something goes wrong, give it another try.
842 <title>Updating TeleDongle Firmware</title>
844 Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
845 firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
847 <orderedlist inheritnum='inherit' numeration='arabic'>
849 Find the 'programming cable' that you got as part of the starter
850 kit, that has a red 8-pin MicroMaTch connector on one end and a
851 red 4-pin MicroMaTch connector on the other end.
854 Find the USB cable that you got as part of the starter kit, and
855 plug the "mini" end in to the mating connector on TeleMetrum or TeleDongle.
858 Take the 2 screws out of the TeleDongle case to get access
859 to the circuit board.
862 Plug the 8-pin end of the programming cable to the
863 matching connector on the programmer, and the 4-pin end to the
864 matching connector on the TeleDongle.
865 Note that each MicroMaTch connector has an alignment pin that
866 goes through a hole in the PC board when you have the cable
870 Attach a battery to the TeleMetrum board if you're using one.
873 Plug both the programmer and the TeleDongle into your computer's USB
874 ports, and power up the programmer.
877 Run AltosUI, and select 'Flash Image' from the File menu.
880 Pick the programmer device from the list, identifying it as the
884 Select the image you want put on the TeleDongle, which should have a
885 name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
886 in the default directory, if not you may have to poke around
887 your system to find it.
890 Make sure the configuration parameters are reasonable
891 looking. If the serial number and/or RF configuration
892 values aren't right, you'll need to change them. The TeleDongle
893 serial number is on the "bottom" of the circuit board, and can
894 usually be read through the translucent blue plastic case without
895 needing to remove the board from the case.
898 Hit the 'OK' button and the software should proceed to flash
899 the TeleDongle with new firmware, showing a progress bar.
902 Confirm that the TeleDongle board seems to have updated OK, which you
903 can do by plugging in to it over USB and using a terminal program
904 to connect to the board and issue the 'v' command to check
905 the version, etc. Once you're happy, remove the programming cable
906 and put the cover back on the TeleDongle.
909 If something goes wrong, give it another try.
913 Be careful removing the programming cable from the locking 8-pin
914 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
915 screwdriver or knife blade to gently pry the locking ears out
916 slightly to extract the connector. We used a locking connector on
917 TeleMetrum to help ensure that the cabling to companion boards
918 used in a rocket don't ever come loose accidentally in flight.
926 <title>AltosUI</title>
928 The AltosUI program provides a graphical user interface for
929 interacting with the Altus Metrum product family, including
930 TeleMetrum, TeleMini and TeleDongle. AltosUI can monitor telemetry data,
931 configure TeleMetrum, TeleMini and TeleDongle devices and many other
932 tasks. The primary interface window provides a selection of
933 buttons, one for each major activity in the system. This manual
934 is split into chapters, each of which documents one of the tasks
935 provided from the top-level toolbar.
938 <title>Monitor Flight</title>
939 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
941 Selecting this item brings up a dialog box listing all of the
942 connected TeleDongle devices. When you choose one of these,
943 AltosUI will create a window to display telemetry data as
944 received by the selected TeleDongle device.
947 All telemetry data received are automatically recorded in
948 suitable log files. The name of the files includes the current
949 date and rocket serial and flight numbers.
952 The radio frequency being monitored by the TeleDongle device is
953 displayed at the top of the window. You can configure the
954 frequency by clicking on the frequency box and selecting the desired
955 frequency. AltosUI remembers the last frequency selected for each
956 TeleDongle and selects that automatically the next time you use
960 Below the TeleDongle frequency selector, the window contains a few
961 significant pieces of information about the altimeter providing
962 the telemetry data stream:
966 <para>The configured call-sign</para>
969 <para>The device serial number</para>
972 <para>The flight number. Each altimeter remembers how many
978 The rocket flight state. Each flight passes through several
979 states including Pad, Boost, Fast, Coast, Drogue, Main and
985 The Received Signal Strength Indicator value. This lets
986 you know how strong a signal TeleDongle is receiving. The
987 radio inside TeleDongle operates down to about -99dBm;
988 weaker signals may not be receivable. The packet link uses
989 error correction and detection techniques which prevent
990 incorrect data from being reported.
995 Finally, the largest portion of the window contains a set of
996 tabs, each of which contain some information about the rocket.
997 They're arranged in 'flight order' so that as the flight
998 progresses, the selected tab automatically switches to display
999 data relevant to the current state of the flight. You can select
1000 other tabs at any time. The final 'table' tab contains all of
1001 the telemetry data in one place.
1004 <title>Launch Pad</title>
1006 The 'Launch Pad' tab shows information used to decide when the
1007 rocket is ready for flight. The first elements include red/green
1008 indicators, if any of these is red, you'll want to evaluate
1009 whether the rocket is ready to launch:
1013 Battery Voltage. This indicates whether the Li-Po battery
1014 powering the TeleMetrum has sufficient charge to last for
1015 the duration of the flight. A value of more than
1016 3.7V is required for a 'GO' status.
1021 Apogee Igniter Voltage. This indicates whether the apogee
1022 igniter has continuity. If the igniter has a low
1023 resistance, then the voltage measured here will be close
1024 to the Li-Po battery voltage. A value greater than 3.2V is
1025 required for a 'GO' status.
1030 Main Igniter Voltage. This indicates whether the main
1031 igniter has continuity. If the igniter has a low
1032 resistance, then the voltage measured here will be close
1033 to the Li-Po battery voltage. A value greater than 3.2V is
1034 required for a 'GO' status.
1039 On-board Data Logging. This indicates whether there is
1040 space remaining on-board to store flight data for the
1041 upcoming flight. If you've downloaded data, but failed
1042 to erase flights, there may not be any space
1043 left. TeleMetrum can store multiple flights, depending
1044 on the configured maximum flight log size. TeleMini
1045 stores only a single flight, so it will need to be
1046 downloaded and erased after each flight to capture
1047 data. This only affects on-board flight logging; the
1048 altimeter will still transmit telemetry and fire
1049 ejection charges at the proper times.
1054 GPS Locked. For a TeleMetrum device, this indicates whether the GPS receiver is
1055 currently able to compute position information. GPS requires
1056 at least 4 satellites to compute an accurate position.
1061 GPS Ready. For a TeleMetrum device, this indicates whether GPS has reported at least
1062 10 consecutive positions without losing lock. This ensures
1063 that the GPS receiver has reliable reception from the
1069 The Launchpad tab also shows the computed launch pad position
1070 and altitude, averaging many reported positions to improve the
1071 accuracy of the fix.
1076 <title>Ascent</title>
1078 This tab is shown during Boost, Fast and Coast
1079 phases. The information displayed here helps monitor the
1080 rocket as it heads towards apogee.
1083 The height, speed and acceleration are shown along with the
1084 maximum values for each of them. This allows you to quickly
1085 answer the most commonly asked questions you'll hear during
1089 The current latitude and longitude reported by the TeleMetrum GPS are
1090 also shown. Note that under high acceleration, these values
1091 may not get updated as the GPS receiver loses position
1092 fix. Once the rocket starts coasting, the receiver should
1093 start reporting position again.
1096 Finally, the current igniter voltages are reported as in the
1097 Launch Pad tab. This can help diagnose deployment failures
1098 caused by wiring which comes loose under high acceleration.
1102 <title>Descent</title>
1104 Once the rocket has reached apogee and (we hope) activated the
1105 apogee charge, attention switches to tracking the rocket on
1106 the way back to the ground, and for dual-deploy flights,
1107 waiting for the main charge to fire.
1110 To monitor whether the apogee charge operated correctly, the
1111 current descent rate is reported along with the current
1112 height. Good descent rates generally range from 15-30m/s.
1115 For TeleMetrum altimeters, you can locate the rocket in the sky
1116 using the elevation and
1117 bearing information to figure out where to look. Elevation is
1118 in degrees above the horizon. Bearing is reported in degrees
1119 relative to true north. Range can help figure out how big the
1120 rocket will appear. Note that all of these values are relative
1121 to the pad location. If the elevation is near 90°, the rocket
1122 is over the pad, not over you.
1125 Finally, the igniter voltages are reported in this tab as
1126 well, both to monitor the main charge as well as to see what
1127 the status of the apogee charge is.
1131 <title>Landed</title>
1133 Once the rocket is on the ground, attention switches to
1134 recovery. While the radio signal is generally lost once the
1135 rocket is on the ground, the last reported GPS position is
1136 generally within a short distance of the actual landing location.
1139 The last reported GPS position is reported both by
1140 latitude and longitude as well as a bearing and distance from
1141 the launch pad. The distance should give you a good idea of
1142 whether you'll want to walk or hitch a ride. Take the reported
1143 latitude and longitude and enter them into your hand-held GPS
1144 unit and have that compute a track to the landing location.
1147 Both TeleMini and TeleMetrum will continue to transmit RDF
1148 tones after landing, allowing you to locate the rocket by
1149 following the radio signal. You may need to get away from
1150 the clutter of the flight line, or even get up on a hill (or
1151 your neighbor's RV) to receive the RDF signal.
1154 The maximum height, speed and acceleration reported
1155 during the flight are displayed for your admiring observers.
1158 To get more detailed information about the flight, you can
1159 click on the 'Graph Flight' button which will bring up a
1160 graph window for the current flight.
1164 <title>Site Map</title>
1166 When the TeleMetrum gets a GPS fix, the Site Map tab will map
1167 the rocket's position to make it easier for you to locate the
1168 rocket, both while it is in the air, and when it has landed. The
1169 rocket's state is indicated by color: white for pad, red for
1170 boost, pink for fast, yellow for coast, light blue for drogue,
1171 dark blue for main, and black for landed.
1174 The map's scale is approximately 3m (10ft) per pixel. The map
1175 can be dragged using the left mouse button. The map will attempt
1176 to keep the rocket roughly centered while data is being received.
1179 Images are fetched automatically via the Google Maps Static API,
1180 and are cached for reuse. If map images cannot be downloaded,
1181 the rocket's path will be traced on a dark gray background
1185 You can pre-load images for your favorite launch sites
1186 before you leave home; check out the 'Preload Maps' section below.
1191 <title>Save Flight Data</title>
1193 The altimeter records flight data to its internal flash memory.
1194 The TeleMetrum data is recorded at a much higher rate than the telemetry
1195 system can handle, and is not subject to radio drop-outs. As
1196 such, it provides a more complete and precise record of the
1197 flight. The 'Save Flight Data' button allows you to read the
1198 flash memory and write it to disk. As TeleMini has only a barometer, it
1199 records data at the same rate as the telemetry signal, but there will be
1200 no data lost due to telemetry drop-outs.
1203 Clicking on the 'Save Flight Data' button brings up a list of
1204 connected TeleMetrum and TeleDongle devices. If you select a
1205 TeleMetrum device, the flight data will be downloaded from that
1206 device directly. If you select a TeleDongle device, flight data
1207 will be downloaded from a TeleMetrum or TeleMini device connected via the
1208 packet command link to the specified TeleDongle. See the chapter
1209 on Packet Command Mode for more information about this.
1212 After the device has been selected, a dialog showing the
1213 flight data saved in the device will be shown allowing you to
1214 select which flights to download and which to delete. With
1215 version 0.9 or newer firmware, you must erase flights in order
1216 for the space they consume to be reused by another
1217 flight. This prevents you from accidentally losing flight data
1218 if you neglect to download data before flying again. Note that
1219 if there is no more space available in the device, then no
1220 data will be recorded for a flight.
1223 The file name for each flight log is computed automatically
1224 from the recorded flight date, altimeter serial number and
1225 flight number information.
1229 <title>Replay Flight</title>
1231 Select this button and you are prompted to select a flight
1232 record file, either a .telem file recording telemetry data or a
1233 .eeprom file containing flight data saved from the altimeter
1237 Once a flight record is selected, the flight monitor interface
1238 is displayed and the flight is re-enacted in real time. Check
1239 the Monitor Flight chapter above to learn how this window operates.
1243 <title>Graph Data</title>
1245 Select this button and you are prompted to select a flight
1246 record file, either a .telem file recording telemetry data or a
1247 .eeprom file containing flight data saved from
1251 Once a flight record is selected, a window with two tabs is
1252 opened. The first tab contains a graph with acceleration
1253 (blue), velocity (green) and altitude (red) of the flight are
1254 plotted and displayed, measured in metric units. The
1255 apogee(yellow) and main(magenta) igniter voltages are also
1256 displayed; high voltages indicate continuity, low voltages
1257 indicate open circuits. The second tab contains some basic
1261 The graph can be zoomed into a particular area by clicking and
1262 dragging down and to the right. Once zoomed, the graph can be
1263 reset by clicking and dragging up and to the left. Holding down
1264 control and clicking and dragging allows the graph to be panned.
1265 The right mouse button causes a pop-up menu to be displayed, giving
1266 you the option save or print the plot.
1269 Note that telemetry files will generally produce poor graphs
1270 due to the lower sampling rate and missed telemetry packets.
1271 Use saved flight data for graphing where possible.
1275 <title>Export Data</title>
1277 This tool takes the raw data files and makes them available for
1278 external analysis. When you select this button, you are prompted to select a flight
1279 data file (either .eeprom or .telem will do, remember that
1280 .eeprom files contain higher resolution and more continuous
1281 data). Next, a second dialog appears which is used to select
1282 where to write the resulting file. It has a selector to choose
1283 between CSV and KML file formats.
1286 <title>Comma Separated Value Format</title>
1288 This is a text file containing the data in a form suitable for
1289 import into a spreadsheet or other external data analysis
1290 tool. The first few lines of the file contain the version and
1291 configuration information from the altimeter, then
1292 there is a single header line which labels all of the
1293 fields. All of these lines start with a '#' character which
1294 most tools can be configured to skip over.
1297 The remaining lines of the file contain the data, with each
1298 field separated by a comma and at least one space. All of
1299 the sensor values are converted to standard units, with the
1300 barometric data reported in both pressure, altitude and
1301 height above pad units.
1305 <title>Keyhole Markup Language (for Google Earth)</title>
1307 This is the format used by
1308 Googleearth to provide an overlay within that
1309 application. With this, you can use Googleearth to see the
1310 whole flight path in 3D.
1315 <title>Configure Altimeter</title>
1317 Select this button and then select either a TeleMetrum or
1318 TeleDongle Device from the list provided. Selecting a TeleDongle
1319 device will use Packet Command Mode to configure a remote
1320 altimeter. Learn how to use this in the Packet Command
1324 The first few lines of the dialog provide information about the
1325 connected device, including the product name,
1326 software version and hardware serial number. Below that are the
1327 individual configuration entries.
1330 At the bottom of the dialog, there are four buttons:
1335 Save. This writes any changes to the
1336 configuration parameter block in flash memory. If you don't
1337 press this button, any changes you make will be lost.
1342 Reset. This resets the dialog to the most recently saved values,
1343 erasing any changes you have made.
1348 Reboot. This reboots the device. Use this to
1349 switch from idle to pad mode by rebooting once the rocket is
1350 oriented for flight.
1355 Close. This closes the dialog. Any unsaved changes will be
1361 The rest of the dialog contains the parameters to be configured.
1364 <title>Main Deploy Altitude</title>
1366 This sets the altitude (above the recorded pad altitude) at
1367 which the 'main' igniter will fire. The drop-down menu shows
1368 some common values, but you can edit the text directly and
1369 choose whatever you like. If the apogee charge fires below
1370 this altitude, then the main charge will fire two seconds
1371 after the apogee charge fires.
1375 <title>Apogee Delay</title>
1377 When flying redundant electronics, it's often important to
1378 ensure that multiple apogee charges don't fire at precisely
1379 the same time as that can over pressurize the apogee deployment
1380 bay and cause a structural failure of the air-frame. The Apogee
1381 Delay parameter tells the flight computer to fire the apogee
1382 charge a certain number of seconds after apogee has been
1387 <title>Radio Frequency</title>
1389 This configures which of the configured frequencies to use for both
1390 telemetry and packet command mode. Note that if you set this
1391 value via packet command mode, you will have to reconfigure
1392 the TeleDongle frequency before you will be able to use packet
1397 <title>Radio Calibration</title>
1399 The radios in every Altus Metrum device are calibrated at the
1400 factory to ensure that they transmit and receive on the
1401 specified frequency. You can adjust that
1402 calibration by changing this value. To change the TeleDongle's
1403 calibration, you must reprogram the unit completely.
1407 <title>Callsign</title>
1409 This sets the call sign included in each telemetry packet. Set this
1410 as needed to conform to your local radio regulations.
1414 <title>Maximum Flight Log Size</title>
1416 This sets the space (in kilobytes) allocated for each flight
1417 log. The available space will be divided into chunks of this
1418 size. A smaller value will allow more flights to be stored,
1419 a larger value will record data from longer flights.
1422 During ascent, TeleMetrum records barometer and
1423 accelerometer values 100 times per second, other analog
1424 information (voltages and temperature) 6 times per second
1425 and GPS data once per second. During descent, the non-GPS
1426 data is recorded 1/10th as often. Each barometer +
1427 accelerometer record takes 8 bytes.
1430 The default, 192kB, will store over 200 seconds of data at
1431 the ascent rate, or over 2000 seconds of data at the descent
1432 rate. That's plenty for most flights. This leaves enough
1433 storage for five flights in a 1MB system, or 10 flights in a
1437 The configuration block takes the last available block of
1438 memory, on v1.0 boards that's just 256 bytes. However, the
1439 flash part on the v1.1 boards uses 64kB for each block.
1442 TeleMini has 5kB of on-board storage, which is plenty for a
1443 single flight. Make sure you download and delete the data
1444 before a subsequent flight or it will not log any data.
1448 <title>Ignite Mode</title>
1450 TeleMetrum and TeleMini provide two igniter channels as they
1451 were originally designed as dual-deploy flight
1452 computers. This configuration parameter allows the two
1453 channels to be used in different configurations.
1458 Dual Deploy. This is the usual mode of operation; the
1459 'apogee' channel is fired at apogee and the 'main'
1460 channel at the height above ground specified by the
1461 'Main Deploy Altitude' during descent.
1466 Redundant Apogee. This fires both channels at
1467 apogee, the 'apogee' channel first followed after a two second
1468 delay by the 'main' channel.
1473 Redundant Main. This fires both channels at the
1474 height above ground specified by the Main Deploy
1475 Altitude setting during descent. The 'apogee'
1476 channel is fired first, followed after a two second
1477 delay by the 'main' channel.
1483 <title>Pad Orientation</title>
1485 Because it includes an accelerometer, TeleMetrum is
1486 sensitive to the orientation of the board. By default, it
1487 expects the antenna end to point forward. This parameter
1488 allows that default to be changed, permitting the board to
1489 be mounted with the antenna pointing aft instead.
1494 Antenna Up. In this mode, the antenna end of the
1495 TeleMetrum board must point forward, in line with the
1496 expected flight path.
1501 Antenna Down. In this mode, the antenna end of the
1502 TeleMetrum board must point aft, in line with the
1503 expected flight path.
1510 <title>Configure AltosUI</title>
1512 This button presents a dialog so that you can configure the AltosUI global settings.
1515 <title>Voice Settings</title>
1517 AltosUI provides voice announcements during flight so that you
1518 can keep your eyes on the sky and still get information about
1519 the current flight status. However, sometimes you don't want
1524 <para>Enable—turns all voice announcements on and off</para>
1528 Test Voice—Plays a short message allowing you to verify
1529 that the audio system is working and the volume settings
1536 <title>Log Directory</title>
1538 AltosUI logs all telemetry data and saves all TeleMetrum flash
1539 data to this directory. This directory is also used as the
1540 staring point when selecting data files for display or export.
1543 Click on the directory name to bring up a directory choosing
1544 dialog, select a new directory and click 'Select Directory' to
1545 change where AltosUI reads and writes data files.
1549 <title>Callsign</title>
1551 This value is used in command packet mode and is transmitted
1552 in each packet sent from TeleDongle and received from
1553 TeleMetrum. It is not used in telemetry mode as that transmits
1554 packets only from TeleMetrum to TeleDongle. Configure this
1555 with the AltosUI operators call sign as needed to comply with
1556 your local radio regulations.
1560 <title>Font Size</title>
1562 Selects the set of fonts used in the flight monitor
1563 window. Choose between the small, medium and large sets.
1567 <title>Serial Debug</title>
1569 This causes all communication with a connected device to be
1570 dumped to the console from which AltosUI was started. If
1571 you've started it from an icon or menu entry, the output
1572 will simply be discarded. This mode can be useful to debug
1573 various serial communication issues.
1577 <title>Manage Frequencies</title>
1579 This brings up a dialog where you can configure the set of
1580 frequencies shown in the various frequency menus. You can
1581 add as many as you like, or even reconfigure the default
1582 set. Changing this list does not affect the frequency
1583 settings of any devices, it only changes the set of
1584 frequencies shown in the menus.
1589 <title>Flash Image</title>
1591 This reprograms any Altus Metrum device by using a TeleMetrum
1592 or TeleDongle as a programming dongle. Please read the
1593 directions for flashing devices in the Updating Device
1594 Firmware section above
1597 Once you have the programmer and target devices connected,
1598 push the 'Flash Image' button. That will present a dialog box
1599 listing all of the connected devices. Carefully select the
1600 programmer device, not the device to be programmed.
1603 Next, select the image to flash to the device. These are named
1604 with the product name and firmware version. The file selector
1605 will start in the directory containing the firmware included
1606 with the AltosUI package. Navigate to the directory containing
1607 the desired firmware if it isn't there.
1610 Next, a small dialog containing the device serial number and
1611 RF calibration values should appear. If these values are
1612 incorrect (possibly due to a corrupted image in the device),
1613 enter the correct values here.
1616 Finally, a dialog containing a progress bar will follow the
1617 programming process.
1620 When programming is complete, the target device will
1621 reboot. Note that if the target device is connected via USB, you
1622 will have to unplug it and then plug it back in for the USB
1623 connection to reset so that you can communicate with the device
1628 <title>Fire Igniter</title>
1630 This activates the igniter circuits in TeleMetrum to help test
1631 recovery systems deployment. Because this command can operate
1632 over the Packet Command Link, you can prepare the rocket as
1633 for flight and then test the recovery system without needing
1634 to snake wires inside the air-frame.
1637 Selecting the 'Fire Igniter' button brings up the usual device
1638 selection dialog. Pick the desired TeleDongle or TeleMetrum
1639 device. This brings up another window which shows the current
1640 continuity test status for both apogee and main charges.
1643 Next, select the desired igniter to fire. This will enable the
1647 Select the 'Arm' button. This enables the 'Fire' button. The
1648 word 'Arm' is replaced by a countdown timer indicating that
1649 you have 10 seconds to press the 'Fire' button or the system
1650 will deactivate, at which point you start over again at
1651 selecting the desired igniter.
1655 <title>Scan Channels</title>
1657 This listens for telemetry packets on all of the configured
1658 frequencies, displaying information about each device it
1659 receives a packet from. You can select which of the three
1660 telemetry formats should be tried; by default, it only listens
1661 for the standard telemetry packets used in v1.0 and later
1666 <title>Load Maps</title>
1668 Before heading out to a new launch site, you can use this to
1669 load satellite images in case you don't have internet
1670 connectivity at the site. This loads a fairly large area
1671 around the launch site, which should cover any flight you're likely to make.
1674 There's a drop-down menu of launch sites we know about; if
1675 your favorites aren't there, please let us know the lat/lon
1676 and name of the site. The contents of this list are actually
1677 downloaded at run-time, so as new sites are sent in, they'll
1678 get automatically added to this list.
1681 If the launch site isn't in the list, you can manually enter the lat/lon values
1684 Clicking the 'Load Map' button will fetch images from Google
1685 Maps; note that Google limits how many images you can fetch at
1686 once, so if you load more than one launch site, you may get
1687 some gray areas in the map which indicate that Google is tired
1688 of sending data to you. Try again later.
1692 <title>Monitor Idle</title>
1694 This brings up a dialog similar to the Monitor Flight UI,
1695 except it works with the altimeter in "idle" mode by sending
1696 query commands to discover the current state rather than
1697 listening for telemetry packets.
1702 <title>Using Altus Metrum Products</title>
1704 <title>Being Legal</title>
1706 First off, in the US, you need an <ulink url="http://www.altusmetrum.org/Radio/">amateur radio license</ulink> or
1707 other authorization to legally operate the radio transmitters that are part
1712 <title>In the Rocket</title>
1714 In the rocket itself, you just need a <ulink url="http://www.altusmetrum.org/TeleMetrum/">TeleMetrum</ulink> or
1715 <ulink url="http://www.altusmetrum.org/TeleMini/">TeleMini</ulink> board and
1716 a Li-Po rechargeable battery. An 860mAh battery weighs less than a 9V
1717 alkaline battery, and will run a TeleMetrum for hours.
1718 A 110mAh battery weighs less than a triple A battery and will run a TeleMetrum for
1719 a few hours, or a TeleMini for much (much) longer.
1722 By default, we ship the altimeters with a simple wire antenna. If your
1723 electronics bay or the air-frame it resides within is made of carbon fiber,
1724 which is opaque to RF signals, you may choose to have an SMA connector
1725 installed so that you can run a coaxial cable to an antenna mounted
1726 elsewhere in the rocket.
1730 <title>On the Ground</title>
1732 To receive the data stream from the rocket, you need an antenna and short
1733 feed-line connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. The
1734 TeleDongle in turn plugs directly into the USB port on a notebook
1735 computer. Because TeleDongle looks like a simple serial port, your computer
1736 does not require special device drivers... just plug it in.
1739 The GUI tool, AltosUI, is written in Java and runs across
1740 Linux, Mac OS and Windows. There's also a suite of C tools
1741 for Linux which can perform most of the same tasks.
1744 After the flight, you can use the RF link to extract the more detailed data
1745 logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
1746 TeleMetrum board directly. Pulling out the data without having to open up
1747 the rocket is pretty cool! A USB cable is also how you charge the Li-Po
1748 battery, so you'll want one of those anyway... the same cable used by lots
1749 of digital cameras and other modern electronic stuff will work fine.
1752 If your TeleMetrum-equipped rocket lands out of sight, you may enjoy having a hand-held GPS
1753 receiver, so that you can put in a way-point for the last reported rocket
1754 position before touch-down. This makes looking for your rocket a lot like
1755 Geo-Caching... just go to the way-point and look around starting from there.
1758 You may also enjoy having a ham radio "HT" that covers the 70cm band... you
1759 can use that with your antenna to direction-find the rocket on the ground
1760 the same way you can use a Walston or Beeline tracker. This can be handy
1761 if the rocket is hiding in sage brush or a tree, or if the last GPS position
1762 doesn't get you close enough because the rocket dropped into a canyon, or
1763 the wind is blowing it across a dry lake bed, or something like that... Keith
1764 and Bdale both currently own and use the Yaesu VX-7R at launches.
1767 So, to recap, on the ground the hardware you'll need includes:
1768 <orderedlist inheritnum='inherit' numeration='arabic'>
1770 an antenna and feed-line
1779 optionally, a hand-held GPS receiver
1782 optionally, an HT or receiver covering 435 MHz
1787 The best hand-held commercial directional antennas we've found for radio
1788 direction finding rockets are from
1789 <ulink url="http://www.arrowantennas.com/" >
1792 The 440-3 and 440-5 are both good choices for finding a
1793 TeleMetrum- or TeleMini- equipped rocket when used with a suitable 70cm HT.
1797 <title>Data Analysis</title>
1799 Our software makes it easy to log the data from each flight, both the
1800 telemetry received over the RF link during the flight itself, and the more
1801 complete data log recorded in the flash memory on the altimeter
1802 board. Once this data is on your computer, our post-flight tools make it
1803 easy to quickly get to the numbers everyone wants, like apogee altitude,
1804 max acceleration, and max velocity. You can also generate and view a
1805 standard set of plots showing the altitude, acceleration, and
1806 velocity of the rocket during flight. And you can even export a TeleMetrum data file
1807 usable with Google Maps and Google Earth for visualizing the flight path
1808 in two or three dimensions!
1811 Our ultimate goal is to emit a set of files for each flight that can be
1812 published as a web page per flight, or just viewed on your local disk with
1817 <title>Future Plans</title>
1819 In the future, we intend to offer "companion boards" for the rocket that will
1820 plug in to TeleMetrum to collect additional data, provide more pyro channels,
1821 and so forth. A reference design for a companion board will be documented
1822 soon, and will be compatible with open source Arduino programming tools.
1825 We are also working on the design of a hand-held ground terminal that will
1826 allow monitoring the rocket's status, collecting data during flight, and
1827 logging data after flight without the need for a notebook computer on the
1828 flight line. Particularly since it is so difficult to read most notebook
1829 screens in direct sunlight, we think this will be a great thing to have.
1832 Because all of our work is open, both the hardware designs and the software,
1833 if you have some great idea for an addition to the current Altus Metrum family,
1834 feel free to dive in and help! Or let us know what you'd like to see that
1835 we aren't already working on, and maybe we'll get excited about it too...
1840 <title>Altimeter Installation Recommendations</title>
1842 Building high-power rockets that fly safely is hard enough. Mix
1843 in some sophisticated electronics and a bunch of radio energy
1844 and oftentimes you find few perfect solutions. This chapter
1845 contains some suggestions about how to install Altus Metrum
1846 products into the rocket air-frame, including how to safely and
1847 reliably mix a variety of electronics into the same air-frame.
1850 <title>Mounting the Altimeter</title>
1852 The first consideration is to ensure that the altimeter is
1853 securely fastened to the air-frame. For TeleMetrum, we use
1854 nylon standoffs and nylon screws; they're good to at least 50G
1855 and cannot cause any electrical issues on the board. For
1856 TeleMini, we usually cut small pieces of 1/16" balsa to fit
1857 under the screw holes, and then take 2x56 nylon screws and
1858 screw them through the TeleMini mounting holes, through the
1859 balsa and into the underlying material.
1861 <orderedlist inheritnum='inherit' numeration='arabic'>
1863 Make sure TeleMetrum is aligned precisely along the axis of
1864 acceleration so that the accelerometer can accurately
1865 capture data during the flight.
1868 Watch for any metal touching components on the
1869 board. Shorting out connections on the bottom of the board
1870 can cause the altimeter to fail during flight.
1875 <title>Dealing with the Antenna</title>
1877 The antenna supplied is just a piece of solid, insulated,
1878 wire. If it gets damaged or broken, it can be easily
1879 replaced. It should be kept straight and not cut; bending or
1880 cutting it will change the resonant frequency and/or
1881 impedance, making it a less efficient radiator and thus
1882 reducing the range of the telemetry signal.
1885 Keeping metal away from the antenna will provide better range
1886 and a more even radiation pattern. In most rockets, it's not
1887 entirely possible to isolate the antenna from metal
1888 components; there are often bolts, all-thread and wires from other
1889 electronics to contend with. Just be aware that the more stuff
1890 like this around the antenna, the lower the range.
1893 Make sure the antenna is not inside a tube made or covered
1894 with conducting material. Carbon fiber is the most common
1895 culprit here -- CF is a good conductor and will effectively
1896 shield the antenna, dramatically reducing signal strength and
1897 range. Metallic flake paint is another effective shielding
1898 material which is to be avoided around any antennas.
1901 If the ebay is large enough, it can be convenient to simply
1902 mount the altimeter at one end and stretch the antenna out
1903 inside. Taping the antenna to the sled can keep it straight
1904 under acceleration. If there are metal rods, keep the
1905 antenna as far away as possible.
1908 For a shorter ebay, it's quite practical to have the antenna
1909 run through a bulkhead and into an adjacent bay. Drill a small
1910 hole in the bulkhead, pass the antenna wire through it and
1911 then seal it up with glue or clay. We've also used acrylic
1912 tubing to create a cavity for the antenna wire. This works a
1913 bit better in that the antenna is known to stay straight and
1914 not get folded by recovery components in the bay. Angle the
1915 tubing towards the side wall of the rocket and it ends up
1916 consuming very little space.
1919 If you need to place the antenna at a distance from the
1920 altimeter, you can replace the antenna with an edge-mounted
1921 SMA connector, and then run 50Ω coax from the board to the
1922 antenna. Building a remote antenna is beyond the scope of this
1927 <title>Preserving GPS Reception</title>
1929 The GPS antenna and receiver in TeleMetrum are highly
1930 sensitive and normally have no trouble tracking enough
1931 satellites to provide accurate position information for
1932 recovering the rocket. However, there are many ways to
1933 attenuate the GPS signal.
1934 <orderedlist inheritnum='inherit' numeration='arabic'>
1936 Conductive tubing or coatings. Carbon fiber and metal
1937 tubing, or metallic paint will all dramatically attenuate the
1938 GPS signal. We've never heard of anyone successfully
1939 receiving GPS from inside these materials.
1942 Metal components near the GPS patch antenna. These will
1943 de-tune the patch antenna, changing the resonant frequency
1944 away from the L1 carrier and reduce the effectiveness of the
1945 antenna. You can place as much stuff as you like beneath the
1946 antenna as that's covered with a ground plane. But, keep
1947 wires and metal out from above the patch antenna.
1953 <title>Radio Frequency Interference</title>
1955 Any altimeter will generate RFI; the digital circuits use
1956 high-frequency clocks that spray radio interference across a
1957 wide band. Altusmetrum altimeters generate intentional radio
1958 signals as well, increasing the amount of RF energy around the board.
1961 Rocketry altimeters also use precise sensors measuring air
1962 pressure and acceleration. Tiny changes in voltage can cause
1963 these sensor readings to vary by a huge amount. When the
1964 sensors start mis-reporting data, the altimeter can either
1965 fire the igniters at the wrong time, or not fire them at all.
1968 Voltages are induced when radio frequency energy is
1969 transmitted from one circuit to another. Here are things that
1970 increase the induced voltage and current:
1974 Keep wires from different circuits apart. Moving circuits
1975 further apart will reduce RFI.
1978 Avoid parallel wires from different circuits. The longer two
1979 wires run parallel to one another, the larger the amount of
1980 transferred energy. Cross wires at right angles to reduce
1984 Twist wires from the same circuits. Two wires the same
1985 distance from the transmitter will get the same amount of
1986 induced energy which will then cancel out. Any time you have
1987 a wire pair running together, twist the pair together to
1988 even out distances and reduce RFI. For altimeters, this
1989 includes battery leads, switch hookups and igniter
1993 Avoid resonant lengths. Know what frequencies are present
1994 in the environment and avoid having wire lengths near a
1995 natural resonant length. Altusmetrum products transmit on the
1996 70cm amateur band, so you should avoid lengths that are a
1997 simple ratio of that length; essentially any multiple of 1/4
1998 of the wavelength (17.5cm).
2003 <title>The Barometric Sensor</title>
2005 Altusmetrum altimeters measure altitude with a barometric
2006 sensor, essentially measuring the amount of air above the
2007 rocket to figure out how high it is. A large number of
2008 measurements are taken as the altimeter initializes itself to
2009 figure out the pad altitude. Subsequent measurements are then
2010 used to compute the height above the pad.
2013 To accurately measure atmospheric pressure, the ebay
2014 containing the altimeter must be vented outside the
2015 air-frame. The vent must be placed in a region of linear
2016 airflow, smooth and not in an area of increasing or decreasing
2020 The barometric sensor in the altimeter is quite sensitive to
2021 chemical damage from the products of APCP or BP combustion, so
2022 make sure the ebay is carefully sealed from any compartment
2023 which contains ejection charges or motors.
2027 <title>Ground Testing</title>
2029 The most important aspect of any installation is careful
2030 ground testing. Bringing an air-frame up to the LCO table which
2031 hasn't been ground tested can lead to delays or ejection
2032 charges firing on the pad, or, even worse, a recovery system
2036 Do a 'full systems' test that includes wiring up all igniters
2037 without any BP and turning on all of the electronics in flight
2038 mode. This will catch any mistakes in wiring and any residual
2039 RFI issues that might accidentally fire igniters at the wrong
2040 time. Let the air-frame sit for several minutes, checking for
2041 adequate telemetry signal strength and GPS lock.
2044 Ground test the ejection charges. Prepare the rocket for
2045 flight, loading ejection charges and igniters. Completely
2046 assemble the air-frame and then use the 'Fire Igniters'
2047 interface through a TeleDongle to command each charge to
2048 fire. Make sure the charge is sufficient to robustly separate
2049 the air-frame and deploy the recovery system.
2054 <title>Hardware Specifications</title>
2056 <title>TeleMetrum Specifications</title>
2060 Recording altimeter for model rocketry.
2065 Supports dual deployment (can fire 2 ejection charges).
2070 70cm ham-band transceiver for telemetry down-link.
2075 Barometric pressure sensor good to 45k feet MSL.
2080 1-axis high-g accelerometer for motor characterization, capable of
2081 +/- 50g using default part.
2086 On-board, integrated GPS receiver with 5Hz update rate capability.
2091 On-board 1 megabyte non-volatile memory for flight data storage.
2096 USB interface for battery charging, configuration, and data recovery.
2101 Fully integrated support for Li-Po rechargeable batteries.
2106 Uses Li-Po to fire e-matches, can be modified to support
2107 optional separate pyro battery if needed.
2112 2.75 x 1 inch board designed to fit inside 29mm air-frame coupler tube.
2118 <title>TeleMini Specifications</title>
2122 Recording altimeter for model rocketry.
2127 Supports dual deployment (can fire 2 ejection charges).
2132 70cm ham-band transceiver for telemetry down-link.
2137 Barometric pressure sensor good to 45k feet MSL.
2142 On-board 5 kilobyte non-volatile memory for flight data storage.
2147 RF interface for battery charging, configuration, and data recovery.
2152 Support for Li-Po rechargeable batteries, using an external charger.
2157 Uses Li-Po to fire e-matches, can be modified to support
2158 optional separate pyro battery if needed.
2163 1.5 x .5 inch board designed to fit inside 18mm air-frame coupler tube.
2172 TeleMetrum seems to shut off when disconnected from the
2173 computer. Make sure the battery is adequately charged. Remember the
2174 unit will pull more power than the USB port can deliver before the
2175 GPS enters "locked" mode. The battery charges best when TeleMetrum
2179 It's impossible to stop the TeleDongle when it's in "p" mode, I have
2180 to unplug the USB cable? Make sure you have tried to "escape out" of
2181 this mode. If this doesn't work the reboot procedure for the
2182 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
2183 outgoing buffer IF your "escape out" ('~~') does not work.
2184 At this point using either 'ao-view' (or possibly
2185 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
2189 The amber LED (on the TeleMetrum) lights up when both
2190 battery and USB are connected. Does this mean it's charging?
2191 Yes, the yellow LED indicates the charging at the 'regular' rate.
2192 If the led is out but the unit is still plugged into a USB port,
2193 then the battery is being charged at a 'trickle' rate.
2196 There are no "dit-dah-dah-dit" sound or lights like the manual mentions?
2197 That's the "pad" mode. Weak batteries might be the problem.
2198 It is also possible that the TeleMetrum is horizontal and the output
2199 is instead a "dit-dit" meaning 'idle'. For TeleMini, it's possible that
2200 it received a command packet which would have left it in "pad" mode.
2203 How do I save flight data?
2204 Live telemetry is written to file(s) whenever AltosUI is connected
2205 to the TeleDongle. The file area defaults to ~/TeleMetrum
2206 but is easily changed using the menus in AltosUI. The files that
2207 are written end in '.telem'. The after-flight
2208 data-dumped files will end in .eeprom and represent continuous data
2209 unlike the RF-linked .telem files that are subject to losses
2210 along the RF data path.
2211 See the above instructions on what and how to save the eeprom stored
2212 data after physically retrieving your altimeter. Make sure to save
2213 the on-board data after each flight; while the TeleMetrum can store
2214 multiple flights, you never know when you'll lose the altimeter...
2218 <title>Notes for Older Software</title>
2221 Before AltosUI was written, using Altus Metrum devices required
2222 some finesse with the Linux command line. There was a limited
2223 GUI tool, ao-view, which provided functionality similar to the
2224 Monitor Flight window in AltosUI, but everything else was a
2225 fairly 80's experience. This appendix includes documentation for
2226 using that software.
2230 Both TeleMetrum and TeleDongle can be directly communicated
2231 with using USB ports. The first thing you should try after getting
2232 both units plugged into to your computer's USB port(s) is to run
2233 'ao-list' from a terminal-window to see what port-device-name each
2234 device has been assigned by the operating system.
2235 You will need this information to access the devices via their
2236 respective on-board firmware and data using other command line
2237 programs in the AltOS software suite.
2240 TeleMini can be communicated with through a TeleDongle device
2241 over the radio link. When first booted, TeleMini listens for a
2242 TeleDongle device and if it receives a packet, it goes into
2243 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be
2244 launched. The easiest way to get it talking is to start the
2245 communication link on the TeleDongle and the power up the
2249 To access the device's firmware for configuration you need a terminal
2250 program such as you would use to talk to a modem. The software
2251 authors prefer using the program 'cu' which comes from the UUCP package
2252 on most Unix-like systems such as Linux. An example command line for
2253 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
2254 indicated from running the
2255 ao-list program. Another reasonable terminal program for Linux is
2256 'cutecom'. The default 'escape'
2257 character used by CU (i.e. the character you use to
2258 issue commands to cu itself instead of sending the command as input
2259 to the connected device) is a '~'. You will need this for use in
2260 only two different ways during normal operations. First is to exit
2261 the program by sending a '~.' which is called a 'escape-disconnect'
2262 and allows you to close-out from 'cu'. The
2263 second use will be outlined later.
2266 All of the Altus Metrum devices share the concept of a two level
2267 command set in their firmware.
2268 The first layer has several single letter commands. Once
2269 you are using 'cu' (or 'cutecom') sending (typing) a '?'
2270 returns a full list of these
2271 commands. The second level are configuration sub-commands accessed
2272 using the 'c' command, for
2273 instance typing 'c?' will give you this second level of commands
2274 (all of which require the
2275 letter 'c' to access). Please note that most configuration options
2276 are stored only in Flash memory; TeleDongle doesn't provide any storage
2277 for these options and so they'll all be lost when you unplug it.
2280 Try setting these configuration ('c' or second level menu) values. A good
2281 place to start is by setting your call sign. By default, the boards
2282 use 'N0CALL' which is cute, but not exactly legal!
2283 Spend a few minutes getting comfortable with the units, their
2284 firmware, and 'cu' (or possibly 'cutecom').
2285 For instance, try to send
2286 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
2287 Verify you can connect and disconnect from the units while in your
2288 terminal program by sending the escape-disconnect mentioned above.
2291 Note that the 'reboot' command, which is very useful on the altimeters,
2292 will likely just cause problems with the dongle. The *correct* way
2293 to reset the dongle is just to unplug and re-plug it.
2296 A fun thing to do at the launch site and something you can do while
2297 learning how to use these units is to play with the RF-link access
2298 between an altimeter and the TeleDongle. Be aware that you *must* create
2299 some physical separation between the devices, otherwise the link will
2300 not function due to signal overload in the receivers in each device.
2303 Now might be a good time to take a break and read the rest of this
2304 manual, particularly about the two "modes" that the altimeters
2305 can be placed in. TeleMetrum uses the position of the device when booting
2306 up will determine whether the unit is in "pad" or "idle" mode. TeleMini
2307 enters "idle" mode when it receives a command packet within the first 5 seconds
2308 of being powered up, otherwise it enters "pad" mode.
2311 You can access an altimeter in idle mode from the TeleDongle's USB
2312 connection using the RF link
2313 by issuing a 'p' command to the TeleDongle. Practice connecting and
2314 disconnecting ('~~' while using 'cu') from the altimeter. If
2315 you cannot escape out of the "p" command, (by using a '~~' when in
2316 CU) then it is likely that your kernel has issues. Try a newer version.
2319 Using this RF link allows you to configure the altimeter, test
2320 fire e-matches and igniters from the flight line, check pyro-match
2321 continuity and so forth. You can leave the unit turned on while it
2322 is in 'idle mode' and then place the
2323 rocket vertically on the launch pad, walk away and then issue a
2324 reboot command. The altimeter will reboot and start sending data
2325 having changed to the "pad" mode. If the TeleDongle is not receiving
2326 this data, you can disconnect 'cu' from the TeleDongle using the
2327 procedures mentioned above and THEN connect to the TeleDongle from
2328 inside 'ao-view'. If this doesn't work, disconnect from the
2329 TeleDongle, unplug it, and try again after plugging it back in.
2332 In order to reduce the chance of accidental firing of pyrotechnic
2333 charges, the command to fire a charge is intentionally somewhat
2334 difficult to type, and the built-in help is slightly cryptic to
2335 prevent accidental echoing of characters from the help text back at
2336 the board from firing a charge. The command to fire the apogee
2337 drogue charge is 'i DoIt drogue' and the command to fire the main
2338 charge is 'i DoIt main'.
2341 On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
2342 and 'ao-view' will both auditorily announce and visually indicate
2344 Now you can launch knowing that you have a good data path and
2345 good satellite lock for flight data and recovery. Remember
2346 you MUST tell ao-view to connect to the TeleDongle explicitly in
2347 order for ao-view to be able to receive data.
2350 The altimeters provide RDF (radio direction finding) tones on
2351 the pad, during descent and after landing. These can be used to
2352 locate the rocket using a directional antenna; the signal
2353 strength providing an indication of the direction from receiver to rocket.
2356 TeleMetrum also provides GPS trekking data, which can further simplify
2357 locating the rocket once it has landed. (The last good GPS data
2358 received before touch-down will be on the data screen of 'ao-view'.)
2361 Once you have recovered the rocket you can download the eeprom
2362 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
2363 either a USB cable or over the radio link using TeleDongle.
2364 And by following the man page for 'ao-postflight' you can create
2365 various data output reports, graphs, and even KML data to see the
2366 flight trajectory in Google-earth. (Moving the viewing angle making
2367 sure to connect the yellow lines while in Google-earth is the proper
2371 As for ao-view.... some things are in the menu but don't do anything
2372 very useful. The developers have stopped working on ao-view to focus
2373 on a new, cross-platform ground station program. So ao-view may or
2374 may not be updated in the future. Mostly you just use
2375 the Log and Device menus. It has a wonderful display of the incoming
2376 flight data and I am sure you will enjoy what it has to say to you
2377 once you enable the voice output!
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