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2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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5 <title>The Altus Metrum System</title>
6 <subtitle>An Owner's Manual for TeleMetrum 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>0.8</revnumber>
40 <date>24 November 2010</date>
41 <revremark>Updated for software version 0.8 </revremark>
47 Thanks to Bob Finch, W9YA, NAR 12965, TRA 12350 for writing "The
48 Mere-Mortals Quick Start/Usage Guide to the Altus Metrum Starter
49 Kit" which has turned into the Getting Started chapter in this
50 book. Bob was one of our first customers for a production
51 TeleMetrum, and the enthusiasm that led to his contribution of
52 this section is immensely gratifying and highy appreciated!
55 And thanks to Anthony (AJ) Towns for contributing the
56 AltosUI graphing and site map code and documentation. Free
57 software means that our customers and friends can become our
58 collaborators, and we certainly appreciate this level of
62 Have fun using these products, and we hope to meet all of you
63 out on the rocket flight line somewhere.
66 NAR #87103, TRA #12201
69 NAR #88757, TRA #12200
74 <title>Introduction and Overview</title>
76 Welcome to the Altus Metrum community! Our circuits and software reflect
77 our passion for both hobby rocketry and Free Software. We hope their
78 capabilities and performance will delight you in every way, but by
79 releasing all of our hardware and software designs under open licenses,
80 we also hope to empower you to take as active a role in our collective
84 The focal point of our community is TeleMetrum, a dual deploy altimeter
85 with fully integrated GPS and radio telemetry as standard features, and
86 a "companion interface" that will support optional capabilities in the
90 Complementing TeleMetrum is TeleDongle, a USB to RF interface for
91 communicating with TeleMetrum. Combined with your choice of antenna and
92 notebook computer, TeleDongle and our associated user interface software
93 form a complete ground station capable of logging and displaying in-flight
94 telemetry, aiding rocket recovery, then processing and archiving flight
95 data for analysis and review.
98 More products will be added to the Altus Metrum family over time, and
99 we currently envision that this will be a single, comprehensive manual
100 for the entire product family.
104 <title>Getting Started</title>
106 The first thing to do after you check the inventory of parts in your
107 "starter kit" is to charge the battery by plugging it into the
108 corresponding socket of the TeleMetrum and then using the USB A to
110 cable to plug the Telemetrum into your computer's USB socket. The
111 TeleMetrum circuitry will charge the battery whenever it is plugged
112 in, because the TeleMetrum's on-off switch does NOT control the
113 charging circuitry. When the GPS chip is initially searching for
114 satellites, TeleMetrum will consume more current than it can pull
115 from the usb port, so the battery must be attached in order to get
116 satellite lock. Once GPS is locked, the current consumption goes back
117 down enough to enable charging while
118 running. So it's a good idea to fully charge the battery as your
119 first item of business so there is no issue getting and maintaining
120 satellite lock. The yellow charge indicator led will go out when the
121 battery is nearly full and the charger goes to trickle charge. It
122 can take several hours to fully recharge a deeply discharged battery.
125 The other active device in the starter kit is the TeleDongle USB to
126 RF interface. If you plug it in to your Mac or Linux computer it should
127 "just work", showing up as a serial port device. Windows systems need
128 driver information that is part of the AltOS download to know that the
129 existing USB modem driver will work. If you are using Linux and are
130 having problems, try moving to a fresher kernel (2.6.33 or newer), as
131 the USB serial driver had ugly bugs in some earlier versions.
134 Next you should obtain and install the AltOS utilities. These include
135 the AltosUI ground station program, current firmware images for
136 TeleMetrum and TeleDongle, and a number of standalone utilities that
137 are rarely needed. Pre-built binary packages are available for Debian
138 Linux, Microsoft Windows, and recent MacOSX versions. Full sourcecode
139 and build instructions for some other Linux variants are also available.
140 The latest version may always be downloaded from
141 <ulink url="http://altusmetrum.org/AltOS"/>.
144 Both Telemetrum and TeleDongle can be directly communicated
145 with using USB ports. The first thing you should try after getting
146 both units plugged into to your computer's usb port(s) is to run
147 'ao-list' from a terminal-window to see what port-device-name each
148 device has been assigned by the operating system.
149 You will need this information to access the devices via their
150 respective on-board firmware and data using other command line
151 programs in the AltOS software suite.
154 To access the device's firmware for configuration you need a terminal
155 program such as you would use to talk to a modem. The software
156 authors prefer using the program 'cu' which comes from the UUCP package
157 on most Unix-like systems such as Linux. An example command line for
158 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
159 indicated from running the
160 ao-list program. Another reasonable terminal program for Linux is
161 'cutecom'. The default 'escape'
162 character used by CU (i.e. the character you use to
163 issue commands to cu itself instead of sending the command as input
164 to the connected device) is a '~'. You will need this for use in
165 only two different ways during normal operations. First is to exit
166 the program by sending a '~.' which is called a 'escape-disconnect'
167 and allows you to close-out from 'cu'. The
168 second use will be outlined later.
171 Both TeleMetrum and TeleDongle share the concept of a two level
172 command set in their firmware.
173 The first layer has several single letter commands. Once
174 you are using 'cu' (or 'cutecom') sending (typing) a '?'
175 returns a full list of these
176 commands. The second level are configuration sub-commands accessed
177 using the 'c' command, for
178 instance typing 'c?' will give you this second level of commands
179 (all of which require the
180 letter 'c' to access). Please note that most configuration options
181 are stored only in DataFlash memory, and only TeleMetrum has this
182 memory to save the various values entered like the channel number
183 and your callsign when powered off. TeleDongle requires that you
184 set these each time you plug it in, which ao-view can help with.
187 Try setting these config ('c' or second level menu) values. A good
188 place to start is by setting your call sign. By default, the boards
189 use 'N0CALL' which is cute, but not exactly legal!
190 Spend a few minutes getting comfortable with the units, their
191 firmware, and 'cu' (or possibly 'cutecom').
192 For instance, try to send
193 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
194 Verify you can connect and disconnect from the units while in your
195 terminal program by sending the escape-disconnect mentioned above.
198 Note that the 'reboot' command, which is very useful on TeleMetrum,
199 will likely just cause problems with the dongle. The *correct* way
200 to reset the dongle is just to unplug and re-plug it.
203 A fun thing to do at the launch site and something you can do while
204 learning how to use these units is to play with the rf-link access
205 of the TeleMetrum from the TeleDongle. Be aware that you *must* create
206 some physical separation between the devices, otherwise the link will
207 not function due to signal overload in the receivers in each device.
210 Now might be a good time to take a break and read the rest of this
211 manual, particularly about the two "modes" that the TeleMetrum
212 can be placed in and how the position of the TeleMetrum when booting
213 up will determine whether the unit is in "pad" or "idle" mode.
216 You can access a TeleMetrum in idle mode from the Teledongle's USB
217 connection using the rf link
218 by issuing a 'p' command to the TeleDongle. Practice connecting and
219 disconnecting ('~~' while using 'cu') from the TeleMetrum. If
220 you cannot escape out of the "p" command, (by using a '~~' when in
221 CU) then it is likely that your kernel has issues. Try a newer version.
224 Using this rf link allows you to configure the TeleMetrum, test
225 fire e-matches and igniters from the flight line, check pyro-match
226 continuity and so forth. You can leave the unit turned on while it
227 is in 'idle mode' and then place the
228 rocket vertically on the launch pad, walk away and then issue a
229 reboot command. The TeleMetrum will reboot and start sending data
230 having changed to the "pad" mode. If the TeleDongle is not receiving
231 this data, you can disconnect 'cu' from the Teledongle using the
232 procedures mentioned above and THEN connect to the TeleDongle from
233 inside 'ao-view'. If this doesn't work, disconnect from the
234 TeleDongle, unplug it, and try again after plugging it back in.
237 Eventually the GPS will find enough satellites, lock in on them,
238 and 'ao-view' will both auditorially announce and visually indicate
240 Now you can launch knowing that you have a good data path and
241 good satellite lock for flight data and recovery. Remember
242 you MUST tell ao-view to connect to the TeleDongle explicitly in
243 order for ao-view to be able to receive data.
246 Both RDF (radio direction finding) tones from the TeleMetrum and
247 GPS trekking data are available and together are very useful in
248 locating the rocket once it has landed. (The last good GPS data
249 received before touch-down will be on the data screen of 'ao-view'.)
252 Once you have recovered the rocket you can download the eeprom
253 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
254 either a USB cable or over the radio link using TeleDongle.
255 And by following the man page for 'ao-postflight' you can create
256 various data output reports, graphs, and even kml data to see the
257 flight trajectory in google-earth. (Moving the viewing angle making
258 sure to connect the yellow lines while in google-earth is the proper
262 As for ao-view.... some things are in the menu but don't do anything
263 very useful. The developers have stopped working on ao-view to focus
264 on a new, cross-platform ground station program. So ao-view may or
265 may not be updated in the future. Mostly you just use
266 the Log and Device menus. It has a wonderful display of the incoming
267 flight data and I am sure you will enjoy what it has to say to you
268 once you enable the voice output!
273 The altimeter (TeleMetrum) seems to shut off when disconnected from the
274 computer. Make sure the battery is adequately charged. Remember the
275 unit will pull more power than the USB port can deliver before the
276 GPS enters "locked" mode. The battery charges best when TeleMetrum
280 It's impossible to stop the TeleDongle when it's in "p" mode, I have
281 to unplug the USB cable? Make sure you have tried to "escape out" of
282 this mode. If this doesn't work the reboot procedure for the
283 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
284 outgoing buffer IF your "escape out" ('~~') does not work.
285 At this point using either 'ao-view' (or possibly
286 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
290 The amber LED (on the TeleMetrum/altimeter) lights up when both
291 battery and USB are connected. Does this mean it's charging?
292 Yes, the yellow LED indicates the charging at the 'regular' rate.
293 If the led is out but the unit is still plugged into a USB port,
294 then the battery is being charged at a 'trickle' rate.
297 There are no "dit-dah-dah-dit" sound like the manual mentions?
298 That's the "pad" mode. Weak batteries might be the problem.
299 It is also possible that the unit is horizontal and the output
300 is instead a "dit-dit" meaning 'idle'.
303 It's unclear how to use 'ao-view' and other programs when 'cu'
304 is running. You cannot have more than one program connected to
305 the TeleDongle at one time without apparent data loss as the
306 incoming data will not make it to both programs intact.
307 Disconnect whatever programs aren't currently being used.
310 How do I save flight data?
311 Live telemetry is written to file(s) whenever 'ao-view' is connected
312 to the TeleDongle. The file area defaults to ~/altos
313 but is easily changed using the menus in 'ao-view'. The files that
314 are written end in '.telem'. The after-flight
315 data-dumped files will end in .eeprom and represent continuous data
316 unlike the rf-linked .telem files that are subject to the
317 turnarounds/data-packaging time slots in the half-duplex rf data path.
318 See the above instructions on what and how to save the eeprom stored
319 data after physically retrieving your TeleMetrum. Make sure to save
320 the on-board data after each flight, as the current firmware will
321 over-write any previous flight data during a new flight.
326 <title>Specifications</title>
330 Recording altimeter for model rocketry.
335 Supports dual deployment (can fire 2 ejection charges).
340 70cm ham-band transceiver for telemetry downlink.
345 Barometric pressure sensor good to 45k feet MSL.
350 1-axis high-g accelerometer for motor characterization, capable of
351 +/- 50g using default part.
356 On-board, integrated GPS receiver with 5hz update rate capability.
361 On-board 1 megabyte non-volatile memory for flight data storage.
366 USB interface for battery charging, configuration, and data recovery.
371 Fully integrated support for LiPo rechargeable batteries.
376 Uses LiPo to fire e-matches, support for optional separate pyro
382 2.75 x 1 inch board designed to fit inside 29mm airframe coupler tube.
388 <title>Handling Precautions</title>
390 TeleMetrum is a sophisticated electronic device. When handled gently and
391 properly installed in an airframe, it will deliver impressive results.
392 However, like all electronic devices, there are some precautions you
396 The Lithium Polymer rechargeable batteries used with TeleMetrum have an
397 extraordinary power density. This is great because we can fly with
398 much less battery mass than if we used alkaline batteries or previous
399 generation rechargeable batteries... but if they are punctured
400 or their leads are allowed to short, they can and will release their
402 Thus we recommend that you take some care when handling our batteries
403 and consider giving them some extra protection in your airframe. We
404 often wrap them in suitable scraps of closed-cell packing foam before
405 strapping them down, for example.
408 The TeleMetrum barometric sensor is sensitive to sunlight. In normal
409 mounting situations, it and all of the other surface mount components
410 are "down" towards whatever the underlying mounting surface is, so
411 this is not normally a problem. Please consider this, though, when
412 designing an installation, for example, in a 29mm airframe with a
413 see-through plastic payload bay.
416 The TeleMetrum barometric sensor sampling port must be able to
418 both by not being covered by foam or tape or other materials that might
419 directly block the hole on the top of the sensor, but also by having a
420 suitable static vent to outside air.
423 As with all other rocketry electronics, TeleMetrum must be protected
424 from exposure to corrosive motor exhaust and ejection charge gasses.
428 <title>Hardware Overview</title>
430 TeleMetrum is a 1 inch by 2.75 inch circuit board. It was designed to
431 fit inside coupler for 29mm airframe tubing, but using it in a tube that
432 small in diameter may require some creativity in mounting and wiring
433 to succeed! The default 1/4
434 wave UHF wire antenna attached to the center of the nose-cone end of
435 the board is about 7 inches long, and wiring for a power switch and
436 the e-matches for apogee and main ejection charges depart from the
437 fin can end of the board. Given all this, an ideal "simple" avionics
438 bay for TeleMetrum should have at least 10 inches of interior length.
441 A typical TeleMetrum installation using the on-board GPS antenna and
442 default wire UHF antenna involves attaching only a suitable
443 Lithium Polymer battery, a single pole switch for power on/off, and
444 two pairs of wires connecting e-matches for the apogee and main ejection
448 By default, we use the unregulated output of the LiPo battery directly
449 to fire ejection charges. This works marvelously with standard
450 low-current e-matches like the J-Tek from MJG Technologies, and with
451 Quest Q2G2 igniters. However, if you
452 want or need to use a separate pyro battery, you can do so by adding
453 a second 2mm connector to position B2 on the board and cutting the
454 thick pcb trace connecting the LiPo battery to the pyro circuit between
455 the two silk screen marks on the surface mount side of the board shown
459 We offer two choices of pyro and power switch connector, or you can
460 choose neither and solder wires directly to the board. All three choices
461 are reasonable depending on the constraints of your airframe. Our
462 favorite option when there is sufficient room above the board is to use
463 the Tyco pin header with polarization and locking. If you choose this
464 option, you crimp individual wires for the power switch and e-matches
465 into a mating connector, and installing and removing the TeleMetrum
466 board from an airframe is as easy as plugging or unplugging two
467 connectors. If the airframe will not support this much height or if
468 you want to be able to directly attach e-match leads to the board, we
469 offer a screw terminal block. This is very similar to what most other
470 altimeter vendors provide and so may be the most familiar option.
471 You'll need a very small straight blade screwdriver to connect
472 and disconnect the board in this case, such as you might find in a
473 jeweler's screwdriver set. Finally, you can forego both options and
474 solder wires directly to the board, which may be the best choice for
475 minimum diameter and/or minimum mass designs.
478 For most airframes, the integrated GPS antenna and wire UHF antenna are
479 a great combination. However, if you are installing in a carbon-fiber
480 electronics bay which is opaque to RF signals, you may need to use
481 off-board external antennas instead. In this case, you can order
482 TeleMetrum with an SMA connector for the UHF antenna connection, and
483 you can unplug the integrated GPS antenna and select an appropriate
484 off-board GPS antenna with cable terminating in a U.FL connector.
488 <title>System Operation</title>
490 <title>Firmware Modes </title>
492 The AltOS firmware build for TeleMetrum has two fundamental modes,
493 "idle" and "flight". Which of these modes the firmware operates in
494 is determined by the orientation of the rocket (well, actually the
495 board, of course...) at the time power is switched on. If the rocket
496 is "nose up", then TeleMetrum assumes it's on a rail or rod being
497 prepared for launch, so the firmware chooses flight mode. However,
498 if the rocket is more or less horizontal, the firmware instead enters
502 At power on, you will hear three beeps
503 ("S" in Morse code for startup) and then a pause while
504 TeleMetrum completes initialization and self tests, and decides which
508 In flight or "pad" mode, TeleMetrum turns on the GPS system,
510 state machine, goes into transmit-only mode on the RF link sending
511 telemetry, and waits for launch to be detected. Flight mode is
512 indicated by an audible "di-dah-dah-dit" ("P" for pad) on the
514 beeps indicating the state of the pyrotechnic igniter continuity.
515 One beep indicates apogee continuity, two beeps indicate
516 main continuity, three beeps indicate both apogee and main continuity,
517 and one longer "brap" sound indicates no continuity. For a dual
518 deploy flight, make sure you're getting three beeps before launching!
519 For apogee-only or motor eject flights, do what makes sense.
522 In idle mode, you will hear an audible "di-dit" ("I" for idle), and
523 the normal flight state machine is disengaged, thus
524 no ejection charges will fire. TeleMetrum also listens on the RF
525 link when in idle mode for packet mode requests sent from TeleDongle.
526 Commands can be issued to a TeleMetrum in idle mode over either
527 USB or the RF link equivalently.
528 Idle mode is useful for configuring TeleMetrum, for extracting data
529 from the on-board storage chip after flight, and for ground testing
533 One "neat trick" of particular value when TeleMetrum is used with very
534 large airframes, is that you can power the board up while the rocket
535 is horizontal, such that it comes up in idle mode. Then you can
536 raise the airframe to launch position, use a TeleDongle to open
537 a packet connection, and issue a 'reset' command which will cause
538 TeleMetrum to reboot, realize it's now nose-up, and thus choose
539 flight mode. This is much safer than standing on the top step of a
540 rickety step-ladder or hanging off the side of a launch tower with
541 a screw-driver trying to turn on your avionics before installing
548 TeleMetrum includes a complete GPS receiver. See a later section for
549 a brief explanation of how GPS works that will help you understand
550 the information in the telemetry stream. The bottom line is that
551 the TeleMetrum GPS receiver needs to lock onto at least four
552 satellites to obtain a solid 3 dimensional position fix and know
556 TeleMetrum provides backup power to the GPS chip any time a LiPo
557 battery is connected. This allows the receiver to "warm start" on
558 the launch rail much faster than if every power-on were a "cold start"
559 for the GPS receiver. In typical operations, powering up TeleMetrum
560 on the flight line in idle mode while performing final airframe
561 preparation will be sufficient to allow the GPS receiver to cold
562 start and acquire lock. Then the board can be powered down during
563 RSO review and installation on a launch rod or rail. When the board
564 is turned back on, the GPS system should lock very quickly, typically
565 long before igniter installation and return to the flight line are
570 <title>Ground Testing </title>
572 An important aspect of preparing a rocket using electronic deployment
573 for flight is ground testing the recovery system. Thanks
574 to the bi-directional RF link central to the Altus Metrum system,
575 this can be accomplished in a TeleMetrum-equipped rocket without as
576 much work as you may be accustomed to with other systems. It can
580 Just prep the rocket for flight, then power up TeleMetrum while the
581 airframe is horizontal. This will cause the firmware to go into
582 "idle" mode, in which the normal flight state machine is disabled and
583 charges will not fire without manual command. Then, establish an
584 RF packet connection from a TeleDongle-equipped computer using the
585 P command from a safe distance. You can now command TeleMetrum to
586 fire the apogee or main charges to complete your testing.
589 In order to reduce the chance of accidental firing of pyrotechnic
590 charges, the command to fire a charge is intentionally somewhat
591 difficult to type, and the built-in help is slightly cryptic to
592 prevent accidental echoing of characters from the help text back at
593 the board from firing a charge. The command to fire the apogee
594 drogue charge is 'i DoIt drogue' and the command to fire the main
595 charge is 'i DoIt main'.
599 <title>Radio Link </title>
601 The chip our boards are based on incorporates an RF transceiver, but
602 it's not a full duplex system... each end can only be transmitting or
603 receiving at any given moment. So we had to decide how to manage the
607 By design, TeleMetrum firmware listens for an RF connection when
608 it's in "idle mode" (turned on while the rocket is horizontal), which
609 allows us to use the RF link to configure the rocket, do things like
610 ejection tests, and extract data after a flight without having to
611 crack open the airframe. However, when the board is in "flight
612 mode" (turned on when the rocket is vertical) the TeleMetrum only
613 transmits and doesn't listen at all. That's because we want to put
614 ultimate priority on event detection and getting telemetry out of
615 the rocket and out over
616 the RF link in case the rocket crashes and we aren't able to extract
620 We don't use a 'normal packet radio' mode because they're just too
621 inefficient. The GFSK modulation we use is just FSK with the
622 baseband pulses passed through a
623 Gaussian filter before they go into the modulator to limit the
624 transmitted bandwidth. When combined with the hardware forward error
625 correction support in the cc1111 chip, this allows us to have a very
626 robust 38.4 kilobit data link with only 10 milliwatts of transmit power,
627 a whip antenna in the rocket, and a hand-held Yagi on the ground. We've
628 had flights to above 21k feet AGL with good reception, and calculations
629 suggest we should be good to well over 40k feet AGL with a 5-element yagi on
630 the ground. We hope to fly boards to higher altitudes soon, and would
631 of course appreciate customer feedback on performance in higher
636 <title>Configurable Parameters</title>
638 Configuring a TeleMetrum board for flight is very simple. Because we
639 have both acceleration and pressure sensors, there is no need to set
640 a "mach delay", for example. The few configurable parameters can all
641 be set using a simple terminal program over the USB port or RF link
645 <title>Radio Channel</title>
647 Our firmware supports 10 channels. The default channel 0 corresponds
648 to a center frequency of 434.550 Mhz, and channels are spaced every
649 100 khz. Thus, channel 1 is 434.650 Mhz, and channel 9 is 435.550 Mhz.
650 At any given launch, we highly recommend coordinating who will use
651 each channel and when to avoid interference. And of course, both
652 TeleMetrum and TeleDongle must be configured to the same channel to
653 successfully communicate with each other.
656 To set the radio channel, use the 'c r' command, like 'c r 3' to set
658 As with all 'c' sub-commands, follow this with a 'c w' to write the
659 change to the parameter block in the on-board DataFlash chip on
660 your TeleMetrum board if you want the change to stay in place across reboots.
664 <title>Apogee Delay</title>
666 Apogee delay is the number of seconds after TeleMetrum detects flight
667 apogee that the drogue charge should be fired. In most cases, this
668 should be left at the default of 0. However, if you are flying
669 redundant electronics such as for an L3 certification, you may wish
670 to set one of your altimeters to a positive delay so that both
671 primary and backup pyrotechnic charges do not fire simultaneously.
674 To set the apogee delay, use the 'c d' command.
675 As with all 'c' sub-commands, follow this with a 'c w' to write the
676 change to the parameter block in the on-board DataFlash chip.
679 Please note that the TeleMetrum apogee detection algorithm always
680 fires a fraction of a second *after* apogee. If you are also flying
681 an altimeter like the PerfectFlite MAWD, which only supports selecting
682 0 or 1 seconds of apogee delay, you may wish to set the MAWD to 0
683 seconds delay and set the TeleMetrum to fire your backup 2 or 3
684 seconds later to avoid any chance of both charges firing
685 simultaneously. We've flown several airframes this way quite happily,
686 including Keith's successful L3 cert.
690 <title>Main Deployment Altitude</title>
692 By default, TeleMetrum will fire the main deployment charge at an
693 elevation of 250 meters (about 820 feet) above ground. We think this
694 is a good elevation for most airframes, but feel free to change this
695 to suit. In particular, if you are flying two altimeters, you may
697 deployment elevation for the backup altimeter to be something lower
698 than the primary so that both pyrotechnic charges don't fire
702 To set the main deployment altitude, use the 'c m' command.
703 As with all 'c' sub-commands, follow this with a 'c w' to write the
704 change to the parameter block in the on-board DataFlash chip.
709 <title>Calibration</title>
711 There are only two calibrations required for a TeleMetrum board, and
712 only one for TeleDongle.
715 <title>Radio Frequency</title>
717 The radio frequency is synthesized from a clock based on the 48 Mhz
718 crystal on the board. The actual frequency of this oscillator must be
719 measured to generate a calibration constant. While our GFSK modulation
720 bandwidth is wide enough to allow boards to communicate even when
721 their oscillators are not on exactly the same frequency, performance
722 is best when they are closely matched.
723 Radio frequency calibration requires a calibrated frequency counter.
724 Fortunately, once set, the variation in frequency due to aging and
725 temperature changes is small enough that re-calibration by customers
726 should generally not be required.
729 To calibrate the radio frequency, connect the UHF antenna port to a
730 frequency counter, set the board to channel 0, and use the 'C'
731 command to generate a CW carrier. Wait for the transmitter temperature
732 to stabilize and the frequency to settle down.
733 Then, divide 434.550 Mhz by the
734 measured frequency and multiply by the current radio cal value show
735 in the 'c s' command. For an unprogrammed board, the default value
736 is 1186611. Take the resulting integer and program it using the 'c f'
737 command. Testing with the 'C' command again should show a carrier
738 within a few tens of Hertz of the intended frequency.
739 As with all 'c' sub-commands, follow this with a 'c w' to write the
740 change to the parameter block in the on-board DataFlash chip.
744 <title>Accelerometer</title>
746 The accelerometer we use has its own 5 volt power supply and
747 the output must be passed through a resistive voltage divider to match
748 the input of our 3.3 volt ADC. This means that unlike the barometric
749 sensor, the output of the acceleration sensor is not ratiometric to
750 the ADC converter, and calibration is required. We also support the
751 use of any of several accelerometers from a Freescale family that
752 includes at least +/- 40g, 50g, 100g, and 200g parts. Using gravity,
753 a simple 2-point calibration yields acceptable results capturing both
754 the different sensitivities and ranges of the different accelerometer
755 parts and any variation in power supply voltages or resistor values
756 in the divider network.
759 To calibrate the acceleration sensor, use the 'c a 0' command. You
760 will be prompted to orient the board vertically with the UHF antenna
761 up and press a key, then to orient the board vertically with the
762 UHF antenna down and press a key.
763 As with all 'c' sub-commands, follow this with a 'c w' to write the
764 change to the parameter block in the on-board DataFlash chip.
767 The +1g and -1g calibration points are included in each telemetry
768 frame and are part of the header extracted by ao-dumplog after flight.
769 Note that we always store and return raw ADC samples for each
770 sensor... nothing is permanently "lost" or "damaged" if the
774 In the unlikely event an accel cal that goes badly, it is possible
775 that TeleMetrum may always come up in 'pad mode' and as such not be
776 listening to either the USB or radio interfaces. If that happens,
777 there is a special hook in the firmware to force the board back
778 in to 'idle mode' so you can re-do the cal. To use this hook, you
779 just need to ground the SPI clock pin at power-on. This pin is
780 available as pin 2 on the 8-pin companion connector, and pin 1 is
781 ground. So either carefully install a fine-gauge wire jumper
782 between the two pins closest to the index hole end of the 8-pin
783 connector, or plug in the programming cable to the 8-pin connector
784 and use a small screwdriver or similar to short the two pins closest
785 to the index post on the 4-pin end of the programming cable, and
786 power up the board. It should come up in 'idle mode' (two beeps).
794 <title>Updating Device Firmware</title>
796 The big conceptual thing to realize is that you have to use a
797 TeleDongle as a programmer to update a TeleMetrum, and vice versa.
798 Due to limited memory resources in the cc1111, we don't support
799 programming either unit directly over USB.
802 You may wish to begin by ensuring you have current firmware images.
803 These are distributed as part of the AltOS software bundle that
804 also includes the AltosUI ground station program. Newer ground
805 station versions typically work fine with older firmware versions,
806 so you don't need to update your devices just to try out new
807 software features. You can always download the most recent
808 version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
811 We recommend updating TeleMetrum first, before updating TeleDongle.
814 <title>Updating TeleMetrum Firmware</title>
815 <orderedlist inheritnum='inherit' numeration='arabic'>
817 Find the 'programming cable' that you got as part of the starter
818 kit, that has a red 8-pin MicroMaTch connector on one end and a
819 red 4-pin MicroMaTch connector on the other end.
822 Take the 2 screws out of the TeleDongle case to get access
823 to the circuit board.
826 Plug the 8-pin end of the programming cable to the
827 matching connector on the TeleDongle, and the 4-pin end to the
828 matching connector on the TeleMetrum.
829 Note that each MicroMaTch connector has an alignment pin that
830 goes through a hole in the PC board when you have the cable
834 Attach a battery to the TeleMetrum board.
837 Plug the TeleDongle into your computer's USB port, and power
841 Run AltosUI, and select 'Flash Image' from the File menu.
844 Pick the TeleDongle device from the list, identifying it as the
848 Select the image you want put on the TeleMetrum, which should have a
849 name in the form telemetrum-v1.0-0.7.1.ihx. It should be visible
850 in the default directory, if not you may have to poke around
851 your system to find it.
854 Make sure the configuration parameters are reasonable
855 looking. If the serial number and/or RF configuration
856 values aren't right, you'll need to change them.
859 Hit the 'OK' button and the software should proceed to flash
860 the TeleMetrum with new firmware, showing a progress bar.
863 Confirm that the TeleMetrum board seems to have updated ok, which you
864 can do by plugging in to it over USB and using a terminal program
865 to connect to the board and issue the 'v' command to check
869 If something goes wrong, give it another try.
874 <title>Updating TeleDongle Firmware</title>
876 Updating TeleDongle's firmware is just like updating TeleMetrum
877 firmware, but you switch which board is the programmer and which
878 is the programming target.
880 <orderedlist inheritnum='inherit' numeration='arabic'>
882 Find the 'programming cable' that you got as part of the starter
883 kit, that has a red 8-pin MicroMaTch connector on one end and a
884 red 4-pin MicroMaTch connector on the other end.
887 Find the USB cable that you got as part of the starter kit, and
888 plug the "mini" end in to the mating connector on TeleMetrum.
891 Take the 2 screws out of the TeleDongle case to get access
892 to the circuit board.
895 Plug the 8-pin end of the programming cable to the (latching)
896 matching connector on the TeleMetrum, and the 4-pin end to the
897 matching connector on the TeleDongle.
898 Note that each MicroMaTch connector has an alignment pin that
899 goes through a hole in the PC board when you have the cable
903 Attach a battery to the TeleMetrum board.
906 Plug both TeleMetrum and TeleDongle into your computer's USB
907 ports, and power up the TeleMetrum.
910 Run AltosUI, and select 'Flash Image' from the File menu.
913 Pick the TeleMetrum device from the list, identifying it as the
917 Select the image you want put on the TeleDongle, which should have a
918 name in the form teledongle-v0.2-0.7.1.ihx. It should be visible
919 in the default directory, if not you may have to poke around
920 your system to find it.
923 Make sure the configuration parameters are reasonable
924 looking. If the serial number and/or RF configuration
925 values aren't right, you'll need to change them. The TeleDongle
926 serial number is on the "bottom" of the circuit board, and can
927 usually be read through the translucent blue plastic case without
928 needing to remove the board from the case.
931 Hit the 'OK' button and the software should proceed to flash
932 the TeleDongle with new firmware, showing a progress bar.
935 Confirm that the TeleDongle board seems to have updated ok, which you
936 can do by plugging in to it over USB and using a terminal program
937 to connect to the board and issue the 'v' command to check
938 the version, etc. Once you're happy, remove the programming cable
939 and put the cover back on the TeleDongle.
942 If something goes wrong, give it another try.
946 Be careful removing the programming cable from the locking 8-pin
947 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
948 screwdriver or knife blade to gently pry the locking ears out
949 slightly to extract the connector. We used a locking connector on
950 TeleMetrum to help ensure that the cabling to companion boards
951 used in a rocket don't ever come loose accidentally in flight.
961 <title>AltosUI</title>
963 The AltosUI program provides a graphical user interface for
964 interacting with the Altus Metrum product family, including
965 TeleMetrum and TeleDongle. AltosUI can monitor telemetry data,
966 configure TeleMetrum and TeleDongle devices and many other
967 tasks. The primary interface window provides a selection of
968 buttons, one for each major activity in the system. This manual
969 is split into chapters, each of which documents one of the tasks
970 provided from the top-level toolbar.
973 <title>Packet Command Mode</title>
974 <subtitle>Controlling TeleMetrum Over The Radio Link</subtitle>
976 One of the unique features of the Altus Metrum environment is
977 the ability to create a two way command link between TeleDongle
978 and TeleMetrum using the digital radio transceivers built into
979 each device. This allows you to interact with TeleMetrum from
980 afar, as if it were directly connected to the computer.
983 Any operation which can be performed with TeleMetrum
984 can either be done with TeleMetrum directly connected to
985 the computer via the USB cable, or through the packet
986 link. Simply select the appropriate TeleDongle device when
987 the list of devices is presented and AltosUI will use packet
991 One oddity in the current interface is how AltosUI selects the
992 channel for packet mode communications. Instead of providing
993 an interface to specifically configure the channel, it uses
994 whatever channel was most recently selected for the target
995 TeleDongle device in Monitor Flight mode. If you haven't ever
996 used that mode with the TeleDongle in question, select the
997 Monitor Flight button from the top level UI, pick the
998 appropriate TeleDongle device. Once the flight monitoring
999 window is open, select the desired channel and then close it
1000 down again. All Packet Command Mode operations will now use
1006 Save Flight Data—Recover flight data from the rocket without
1012 Configure TeleMetrum—Reset apogee delays or main deploy
1013 heights to respond to changing launch conditions. You can
1014 also 'reboot' the TeleMetrum device. Use this to remotely
1015 enable the flight computer by turning TeleMetrum on while
1016 horizontal, then once the airframe is oriented for launch,
1017 you can reboot TeleMetrum and have it restart in pad mode
1018 without having to climb the scary ladder.
1023 Fire Igniters—Test your deployment charges without snaking
1024 wires out through holes in the airframe. Simply assembly the
1025 rocket as if for flight with the apogee and main charges
1026 loaded, then remotely command TeleMetrum to fire the
1032 Packet command mode uses the same RF channels as telemetry
1033 mode. Configure the desired TeleDongle channel using the
1034 flight monitor window channel selector and then close that
1035 window before performing the desired operation.
1038 TeleMetrum only enables packet command mode in 'idle' mode, so
1039 make sure you have TeleMetrum lying horizontally when you turn
1040 it on. Otherwise, TeleMetrum will start in 'pad' mode ready for
1041 flight and will not be listening for command packets from TeleDongle.
1044 When packet command mode is enabled, you can monitor the link
1045 by watching the lights on the TeleDongle and TeleMetrum
1046 devices. The red LED will flash each time TeleDongle or
1047 TeleMetrum transmit a packet while the green LED will light up
1048 on TeleDongle while it is waiting to receive a packet from
1053 <title>Monitor Flight</title>
1054 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
1056 Selecting this item brings up a dialog box listing all of the
1057 connected TeleDongle devices. When you choose one of these,
1058 AltosUI will create a window to display telemetry data as
1059 received by the selected TeleDongle device.
1062 All telemetry data received are automatically recorded in
1063 suitable log files. The name of the files includes the current
1064 date and rocket serial and flight numbers.
1067 The radio channel being monitored by the TeleDongle device is
1068 displayed at the top of the window. You can configure the
1069 channel by clicking on the channel box and selecting the desired
1070 channel. AltosUI remembers the last channel selected for each
1071 TeleDongle and selects that automatically the next time you use
1075 Below the TeleDongle channel selector, the window contains a few
1076 significant pieces of information about the TeleMetrum providing
1077 the telemetry data stream:
1081 <para>The TeleMetrum callsign</para>
1084 <para>The TeleMetrum serial number</para>
1087 <para>The flight number. Each TeleMetrum remembers how many
1093 The rocket flight state. Each flight passes through several
1094 states including Pad, Boost, Fast, Coast, Drogue, Main and
1100 The Received Signal Strength Indicator value. This lets
1101 you know how strong a signal TeleDongle is receiving. The
1102 radio inside TeleDongle operates down to about -99dBm;
1103 weaker signals may not be receiveable. The packet link uses
1104 error correction and detection techniques which prevent
1105 incorrect data from being reported.
1110 Finally, the largest portion of the window contains a set of
1111 tabs, each of which contain some information about the rocket.
1112 They're arranged in 'flight order' so that as the flight
1113 progresses, the selected tab automatically switches to display
1114 data relevant to the current state of the flight. You can select
1115 other tabs at any time. The final 'table' tab contains all of
1116 the telemetry data in one place.
1119 <title>Launch Pad</title>
1121 The 'Launch Pad' tab shows information used to decide when the
1122 rocket is ready for flight. The first elements include red/green
1123 indicators, if any of these is red, you'll want to evaluate
1124 whether the rocket is ready to launch:
1128 Battery Voltage. This indicates whether the LiPo battery
1129 powering the TeleMetrum has sufficient charge to last for
1130 the duration of the flight. A value of more than
1131 3.7V is required for a 'GO' status.
1136 Apogee Igniter Voltage. This indicates whether the apogee
1137 igniter has continuity. If the igniter has a low
1138 resistance, then the voltage measured here will be close
1139 to the LiPo battery voltage. A value greater than 3.2V is
1140 required for a 'GO' status.
1145 Main Igniter Voltage. This indicates whether the main
1146 igniter has continuity. If the igniter has a low
1147 resistance, then the voltage measured here will be close
1148 to the LiPo battery voltage. A value greater than 3.2V is
1149 required for a 'GO' status.
1154 GPS Locked. This indicates whether the GPS receiver is
1155 currently able to compute position information. GPS requires
1156 at least 4 satellites to compute an accurate position.
1161 GPS Ready. This indicates whether GPS has reported at least
1162 10 consecutive positions without losing lock. This ensures
1163 that the GPS receiver has reliable reception from the
1169 The LaunchPad tab also shows the computed launch pad position
1170 and altitude, averaging many reported positions to improve the
1171 accuracy of the fix.
1176 <title>Ascent</title>
1178 This tab is shown during Boost, Fast and Coast
1179 phases. The information displayed here helps monitor the
1180 rocket as it heads towards apogee.
1183 The height, speed and acceleration are shown along with the
1184 maxium values for each of them. This allows you to quickly
1185 answer the most commonly asked questions you'll hear during
1189 The current latitude and longitude reported by the GPS are
1190 also shown. Note that under high acceleration, these values
1191 may not get updated as the GPS receiver loses position
1192 fix. Once the rocket starts coasting, the receiver should
1193 start reporting position again.
1196 Finally, the current igniter voltages are reported as in the
1197 Launch Pad tab. This can help diagnose deployment failures
1198 caused by wiring which comes loose under high acceleration.
1202 <title>Descent</title>
1204 Once the rocket has reached apogee and (we hope) activated the
1205 apogee charge, attention switches to tracking the rocket on
1206 the way back to the ground, and for dual-deploy flights,
1207 waiting for the main charge to fire.
1210 To monitor whether the apogee charge operated correctly, the
1211 current descent rate is reported along with the current
1212 height. Good descent rates generally range from 15-30m/s.
1215 To help locate the rocket in the sky, use the elevation and
1216 bearing information to figure out where to look. Elevation is
1217 in degrees above the horizon. Bearing is reported in degrees
1218 relative to true north. Range can help figure out how big the
1219 rocket will appear. Note that all of these values are relative
1220 to the pad location. If the elevation is near 90°, the rocket
1221 is over the pad, not over you.
1224 Finally, the igniter voltages are reported in this tab as
1225 well, both to monitor the main charge as well as to see what
1226 the status of the apogee charge is.
1230 <title>Landed</title>
1232 Once the rocket is on the ground, attention switches to
1233 recovery. While the radio signal is generally lost once the
1234 rocket is on the ground, the last reported GPS position is
1235 generally within a short distance of the actual landing location.
1238 The last reported GPS position is reported both by
1239 latitude and longitude as well as a bearing and distance from
1240 the launch pad. The distance should give you a good idea of
1241 whether you'll want to walk or hitch a ride. Take the reported
1242 latitude and longitude and enter them into your handheld GPS
1243 unit and have that compute a track to the landing location.
1246 Finally, the maximum height, speed and acceleration reported
1247 during the flight are displayed for your admiring observers.
1251 <title>Site Map</title>
1253 When the rocket gets a GPS fix, the Site Map tab will map
1254 the rocket's position to make it easier for you to locate the
1255 rocket, both while it is in the air, and when it has landed. The
1256 rocket's state is indicated by colour: white for pad, red for
1257 boost, pink for fast, yellow for coast, light blue for drogue,
1258 dark blue for main, and black for landed.
1261 The map's scale is approximately 3m (10ft) per pixel. The map
1262 can be dragged using the left mouse button. The map will attempt
1263 to keep the rocket roughly centred while data is being received.
1266 Images are fetched automatically via the Google Maps Static API,
1267 and are cached for reuse. If map images cannot be downloaded,
1268 the rocket's path will be traced on a dark grey background
1274 <title>Save Flight Data</title>
1276 TeleMetrum records flight data to its internal flash memory.
1277 This data is recorded at a much higher rate than the telemetry
1278 system can handle, and is not subject to radio drop-outs. As
1279 such, it provides a more complete and precise record of the
1280 flight. The 'Save Flight Data' button allows you to read the
1281 flash memory and write it to disk.
1284 Clicking on the 'Save Flight Data' button brings up a list of
1285 connected TeleMetrum and TeleDongle devices. If you select a
1286 TeleMetrum device, the flight data will be downloaded from that
1287 device directly. If you select a TeleDongle device, flight data
1288 will be downloaded from a TeleMetrum device connected via the
1289 packet command link to the specified TeleDongle. See the chapter
1290 on Packet Command Mode for more information about this.
1293 The filename for the data is computed automatically from the recorded
1294 flight date, TeleMetrum serial number and flight number
1299 <title>Replay Flight</title>
1301 Select this button and you are prompted to select a flight
1302 record file, either a .telem file recording telemetry data or a
1303 .eeprom file containing flight data saved from the TeleMetrum
1307 Once a flight record is selected, the flight monitor interface
1308 is displayed and the flight is re-enacted in real time. Check
1309 the Monitor Flight chapter above to learn how this window operates.
1313 <title>Graph Data</title>
1315 Select this button and you are prompted to select a flight
1316 record file, either a .telem file recording telemetry data or a
1317 .eeprom file containing flight data saved from the TeleMetrum
1321 Once a flight record is selected, the acceleration (blue),
1322 velocity (green) and altitude (red) of the flight are plotted and
1323 displayed, measured in metric units.
1326 The graph can be zoomed into a particular area by clicking and
1327 dragging down and to the right. Once zoomed, the graph can be
1328 reset by clicking and dragging up and to the left. Holding down
1329 control and clicking and dragging allows the graph to be panned.
1330 The right mouse button causes a popup menu to be displayed, giving
1331 you the option save or print the plot.
1334 Note that telemetry files will generally produce poor graphs
1335 due to the lower sampling rate and missed telemetry packets,
1336 and will also often have significant amounts of data received
1337 while the rocket was waiting on the pad. Use saved flight data
1338 for graphing where possible.
1342 <title>Export Data</title>
1344 This tool takes the raw data files and makes them available for
1345 external analysis. When you select this button, you are prompted to select a flight
1346 data file (either .eeprom or .telem will do, remember that
1347 .eeprom files contain higher resolution and more continuous
1348 data). Next, a second dialog appears which is used to select
1349 where to write the resulting file. It has a selector to choose
1350 between CSV and KML file formats.
1353 <title>Comma Separated Value Format</title>
1355 This is a text file containing the data in a form suitable for
1356 import into a spreadsheet or other external data analysis
1357 tool. The first few lines of the file contain the version and
1358 configuration information from the TeleMetrum device, then
1359 there is a single header line which labels all of the
1360 fields. All of these lines start with a '#' character which
1361 most tools can be configured to skip over.
1364 The remaining lines of the file contain the data, with each
1365 field separated by a comma and at least one space. All of
1366 the sensor values are converted to standard units, with the
1367 barometric data reported in both pressure, altitude and
1368 height above pad units.
1372 <title>Keyhole Markup Language (for Google Earth)</title>
1374 This is the format used by
1375 Googleearth to provide an overlay within that
1376 application. With this, you can use Googleearth to see the
1377 whole flight path in 3D.
1382 <title>Configure TeleMetrum</title>
1384 Select this button and then select either a TeleMetrum or
1385 TeleDongle Device from the list provided. Selecting a TeleDongle
1386 device will use Packet Comamnd Mode to configure remote
1387 TeleMetrum device. Learn how to use this in the Packet Command
1391 The first few lines of the dialog provide information about the
1392 connected TeleMetrum device, including the product name,
1393 software version and hardware serial number. Below that are the
1394 individual configuration entries.
1397 At the bottom of the dialog, there are four buttons:
1402 Save. This writes any changes to the TeleMetrum
1403 configuration parameter block in flash memory. If you don't
1404 press this button, any changes you make will be lost.
1409 Reset. This resets the dialog to the most recently saved values,
1410 erasing any changes you have made.
1415 Reboot. This reboots the TeleMetrum device. Use this to
1416 switch from idle to pad mode by rebooting once the rocket is
1417 oriented for flight.
1422 Close. This closes the dialog. Any unsaved changes will be
1428 The rest of the dialog contains the parameters to be configured.
1431 <title>Main Deploy Altitude</title>
1433 This sets the altitude (above the recorded pad altitude) at
1434 which the 'main' igniter will fire. The drop-down menu shows
1435 some common values, but you can edit the text directly and
1436 choose whatever you like. If the apogee charge fires below
1437 this altitude, then the main charge will fire two seconds
1438 after the apogee charge fires.
1442 <title>Apogee Delay</title>
1444 When flying redundant electronics, it's often important to
1445 ensure that multiple apogee charges don't fire at precisely
1446 the same time as that can overpressurize the apogee deployment
1447 bay and cause a structural failure of the airframe. The Apogee
1448 Delay parameter tells the flight computer to fire the apogee
1449 charge a certain number of seconds after apogee has been
1454 <title>Radio Channel</title>
1456 This configures which of the 10 radio channels to use for both
1457 telemetry and packet command mode. Note that if you set this
1458 value via packet command mode, you will have to reconfigure
1459 the TeleDongle channel before you will be able to use packet
1464 <title>Radio Calibration</title>
1466 The radios in every Altus Metrum device are calibrated at the
1467 factory to ensure that they transmit and receive on the
1468 specified frequency for each channel. You can adjust that
1469 calibration by changing this value. To change the TeleDongle's
1470 calibration, you must reprogram the unit completely.
1474 <title>Callsign</title>
1476 This sets the callsign included in each telemetry packet. Set this
1477 as needed to conform to your local radio regulations.
1482 <title>Configure AltosUI</title>
1484 This button presents a dialog so that you can configure the AltosUI global settings.
1487 <title>Voice Settings</title>
1489 AltosUI provides voice annoucements during flight so that you
1490 can keep your eyes on the sky and still get information about
1491 the current flight status. However, sometimes you don't want
1496 <para>Enable—turns all voice announcements on and off</para>
1500 Test Voice—Plays a short message allowing you to verify
1501 that the audio systme is working and the volume settings
1508 <title>Log Directory</title>
1510 AltosUI logs all telemetry data and saves all TeleMetrum flash
1511 data to this directory. This directory is also used as the
1512 staring point when selecting data files for display or export.
1515 Click on the directory name to bring up a directory choosing
1516 dialog, select a new directory and click 'Select Directory' to
1517 change where AltosUI reads and writes data files.
1521 <title>Callsign</title>
1523 This value is used in command packet mode and is transmitted
1524 in each packet sent from TeleDongle and received from
1525 TeleMetrum. It is not used in telemetry mode as that transmits
1526 packets only from TeleMetrum to TeleDongle. Configure this
1527 with the AltosUI operators callsign as needed to comply with
1528 your local radio regulations.
1533 <title>Flash Image</title>
1535 This reprograms any Altus Metrum device by using a TeleMetrum or
1536 TeleDongle as a programming dongle. Please read the directions
1537 for connecting the programming cable in the main TeleMetrum
1538 manual before reading these instructions.
1541 Once you have the programmer and target devices connected,
1542 push the 'Flash Image' button. That will present a dialog box
1543 listing all of the connected devices. Carefully select the
1544 programmer device, not the device to be programmed.
1547 Next, select the image to flash to the device. These are named
1548 with the product name and firmware version. The file selector
1549 will start in the directory containing the firmware included
1550 with the AltosUI package. Navigate to the directory containing
1551 the desired firmware if it isn't there.
1554 Next, a small dialog containing the device serial number and
1555 RF calibration values should appear. If these values are
1556 incorrect (possibly due to a corrupted image in the device),
1557 enter the correct values here.
1560 Finally, a dialog containing a progress bar will follow the
1561 programming process.
1564 When programming is complete, the target device will
1565 reboot. Note that if the target device is connected via USB, you
1566 will have to unplug it and then plug it back in for the USB
1567 connection to reset so that you can communicate with the device
1572 <title>Fire Igniter</title>
1574 This activates the igniter circuits in TeleMetrum to help test
1575 recovery systems deployment. Because this command can operate
1576 over the Packet Command Link, you can prepare the rocket as
1577 for flight and then test the recovery system without needing
1578 to snake wires inside the airframe.
1581 Selecting the 'Fire Igniter' button brings up the usual device
1582 selection dialog. Pick the desired TeleDongle or TeleMetrum
1583 device. This brings up another window which shows the current
1584 continutity test status for both apogee and main charges.
1587 Next, select the desired igniter to fire. This will enable the
1591 Select the 'Arm' button. This enables the 'Fire' button. The
1592 word 'Arm' is replaced by a countdown timer indicating that
1593 you have 10 seconds to press the 'Fire' button or the system
1594 will deactivate, at which point you start over again at
1595 selecting the desired igniter.
1600 <title>Using Altus Metrum Products</title>
1602 <title>Being Legal</title>
1604 First off, in the US, you need an <ulink url="http://www.altusmetrum.org/Radio/">amateur radio license</ulink> or
1605 other authorization to legally operate the radio transmitters that are part
1610 <title>In the Rocket</title>
1612 In the rocket itself, you just need a <ulink url="http://www.altusmetrum.org/TeleMetrum/">TeleMetrum</ulink> board and
1613 a LiPo rechargeable battery. An 860mAh battery weighs less than a 9V
1614 alkaline battery, and will run a <ulink url="http://www.altusmetrum.org/TeleMetrum/">TeleMetrum</ulink> for hours.
1617 By default, we ship TeleMetrum with a simple wire antenna. If your
1618 electronics bay or the airframe it resides within is made of carbon fiber,
1619 which is opaque to RF signals, you may choose to have an SMA connector
1620 installed so that you can run a coaxial cable to an antenna mounted
1621 elsewhere in the rocket.
1625 <title>On the Ground</title>
1627 To receive the data stream from the rocket, you need an antenna and short
1628 feedline connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. The
1629 TeleDongle in turn plugs directly into the USB port on a notebook
1630 computer. Because TeleDongle looks like a simple serial port, your computer
1631 does not require special device drivers... just plug it in.
1634 The GUI tool, AltosUI, is written in Java and runs across
1635 Linux, Mac OS and Windows. There's also a suite of C tools
1636 for Linux which can perform most of the same tasks.
1639 After the flight, you can use the RF link to extract the more detailed data
1640 logged in the rocket, or you can use a mini USB cable to plug into the
1641 TeleMetrum board directly. Pulling out the data without having to open up
1642 the rocket is pretty cool! A USB cable is also how you charge the LiPo
1643 battery, so you'll want one of those anyway... the same cable used by lots
1644 of digital cameras and other modern electronic stuff will work fine.
1647 If your rocket lands out of sight, you may enjoy having a hand-held GPS
1648 receiver, so that you can put in a waypoint for the last reported rocket
1649 position before touch-down. This makes looking for your rocket a lot like
1650 Geo-Cacheing... just go to the waypoint and look around starting from there.
1653 You may also enjoy having a ham radio "HT" that covers the 70cm band... you
1654 can use that with your antenna to direction-find the rocket on the ground
1655 the same way you can use a Walston or Beeline tracker. This can be handy
1656 if the rocket is hiding in sage brush or a tree, or if the last GPS position
1657 doesn't get you close enough because the rocket dropped into a canyon, or
1658 the wind is blowing it across a dry lake bed, or something like that... Keith
1659 and Bdale both currently own and use the Yaesu VX-7R at launches.
1662 So, to recap, on the ground the hardware you'll need includes:
1663 <orderedlist inheritnum='inherit' numeration='arabic'>
1665 an antenna and feedline
1674 optionally, a handheld GPS receiver
1677 optionally, an HT or receiver covering 435 Mhz
1682 The best hand-held commercial directional antennas we've found for radio
1683 direction finding rockets are from
1684 <ulink url="http://www.arrowantennas.com/" >
1687 The 440-3 and 440-5 are both good choices for finding a
1688 TeleMetrum-equipped rocket when used with a suitable 70cm HT.
1692 <title>Data Analysis</title>
1694 Our software makes it easy to log the data from each flight, both the
1695 telemetry received over the RF link during the flight itself, and the more
1696 complete data log recorded in the DataFlash memory on the TeleMetrum
1697 board. Once this data is on your computer, our postflight tools make it
1698 easy to quickly get to the numbers everyone wants, like apogee altitude,
1699 max acceleration, and max velocity. You can also generate and view a
1700 standard set of plots showing the altitude, acceleration, and
1701 velocity of the rocket during flight. And you can even export a data file
1702 useable with Google Maps and Google Earth for visualizing the flight path
1703 in two or three dimensions!
1706 Our ultimate goal is to emit a set of files for each flight that can be
1707 published as a web page per flight, or just viewed on your local disk with
1712 <title>Future Plans</title>
1714 In the future, we intend to offer "companion boards" for the rocket that will
1715 plug in to TeleMetrum to collect additional data, provide more pyro channels,
1716 and so forth. A reference design for a companion board will be documented
1717 soon, and will be compatible with open source Arduino programming tools.
1720 We are also working on the design of a hand-held ground terminal that will
1721 allow monitoring the rocket's status, collecting data during flight, and
1722 logging data after flight without the need for a notebook computer on the
1723 flight line. Particularly since it is so difficult to read most notebook
1724 screens in direct sunlight, we think this will be a great thing to have.
1727 Because all of our work is open, both the hardware designs and the software,
1728 if you have some great idea for an addition to the current Altus Metrum family,
1729 feel free to dive in and help! Or let us know what you'd like to see that
1730 we aren't already working on, and maybe we'll get excited about it too...