1 <?xml version="1.0" encoding="utf-8" ?>
2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
3 "/usr/share/xml/docbook/schema/dtd/4.5/docbookx.dtd">
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 highy 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 is 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 airframe.
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 the battery charger board,
156 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. If you are using Linux and are
165 having problems, try moving to a fresher kernel (2.6.33 or newer), as
166 the USB serial driver had ugly bugs in some earlier versions.
169 Next you should obtain and install the AltOS utilities. These include
170 the AltosUI ground station program, current firmware images for
171 TeleMetrum, TeleMini and TeleDongle, and a number of standalone utilities that
172 are rarely needed. Pre-built binary packages are available for Debian
173 Linux, Microsoft Windows, and recent MacOSX versions. Full sourcecode
174 and build instructions for some other Linux variants are also available.
175 The latest version may always be downloaded from
176 <ulink url="http://altusmetrum.org/AltOS"/>.
179 Both Telemetrum and TeleDongle can be directly communicated
180 with using USB ports. The first thing you should try after getting
181 both units plugged into to your computer's usb port(s) is to run
182 'ao-list' from a terminal-window to see what port-device-name each
183 device has been assigned by the operating system.
184 You will need this information to access the devices via their
185 respective on-board firmware and data using other command line
186 programs in the AltOS software suite.
189 TeleMini can be communicated with through a TeleDongle device
190 over the radio link. When first booted, TeleMini listens for a
191 TeleDongle device and if it receives a packet, it goes into
192 'idle' mode. Otherwise, it goes into 'pad' mode and waits to be
193 launched. The easiest way to get it talking is to start the
194 communication link on the TeleDongle and the power up the
198 To access the device's firmware for configuration you need a terminal
199 program such as you would use to talk to a modem. The software
200 authors prefer using the program 'cu' which comes from the UUCP package
201 on most Unix-like systems such as Linux. An example command line for
202 cu might be 'cu -l /dev/ttyACM0', substituting the correct number
203 indicated from running the
204 ao-list program. Another reasonable terminal program for Linux is
205 'cutecom'. The default 'escape'
206 character used by CU (i.e. the character you use to
207 issue commands to cu itself instead of sending the command as input
208 to the connected device) is a '~'. You will need this for use in
209 only two different ways during normal operations. First is to exit
210 the program by sending a '~.' which is called a 'escape-disconnect'
211 and allows you to close-out from 'cu'. The
212 second use will be outlined later.
215 All of the Altus Metrum devices share the concept of a two level
216 command set in their firmware.
217 The first layer has several single letter commands. Once
218 you are using 'cu' (or 'cutecom') sending (typing) a '?'
219 returns a full list of these
220 commands. The second level are configuration sub-commands accessed
221 using the 'c' command, for
222 instance typing 'c?' will give you this second level of commands
223 (all of which require the
224 letter 'c' to access). Please note that most configuration options
225 are stored only in Flash memory; TeleDongle doesn't provide any storage
226 for these options and so they'll all be lost when you unplug it.
229 Try setting these config ('c' or second level menu) values. A good
230 place to start is by setting your call sign. By default, the boards
231 use 'N0CALL' which is cute, but not exactly legal!
232 Spend a few minutes getting comfortable with the units, their
233 firmware, and 'cu' (or possibly 'cutecom').
234 For instance, try to send
235 (type) a 'c r 2' and verify the channel change by sending a 'c s'.
236 Verify you can connect and disconnect from the units while in your
237 terminal program by sending the escape-disconnect mentioned above.
240 Note that the 'reboot' command, which is very useful on the altimeters,
241 will likely just cause problems with the dongle. The *correct* way
242 to reset the dongle is just to unplug and re-plug it.
245 A fun thing to do at the launch site and something you can do while
246 learning how to use these units is to play with the rf-link access
247 between an altimeter and the TeleDongle. Be aware that you *must* create
248 some physical separation between the devices, otherwise the link will
249 not function due to signal overload in the receivers in each device.
252 Now might be a good time to take a break and read the rest of this
253 manual, particularly about the two "modes" that the altimeters
254 can be placed in. TeleMetrum uses the position of the device when booting
255 up will determine whether the unit is in "pad" or "idle" mode. TeleMini
256 enters "idle" mode when it receives a command packet within the first 5 seconds
257 of being powered up, otherwise it enters "pad" mode.
260 You can access an altimeter in idle mode from the Teledongle's USB
261 connection using the rf link
262 by issuing a 'p' command to the TeleDongle. Practice connecting and
263 disconnecting ('~~' while using 'cu') from the altimeter. If
264 you cannot escape out of the "p" command, (by using a '~~' when in
265 CU) then it is likely that your kernel has issues. Try a newer version.
268 Using this rf link allows you to configure the altimeter, test
269 fire e-matches and igniters from the flight line, check pyro-match
270 continuity and so forth. You can leave the unit turned on while it
271 is in 'idle mode' and then place the
272 rocket vertically on the launch pad, walk away and then issue a
273 reboot command. The altimeter will reboot and start sending data
274 having changed to the "pad" mode. If the TeleDongle is not receiving
275 this data, you can disconnect 'cu' from the Teledongle using the
276 procedures mentioned above and THEN connect to the TeleDongle from
277 inside 'ao-view'. If this doesn't work, disconnect from the
278 TeleDongle, unplug it, and try again after plugging it back in.
281 On TeleMetrum, the GPS will eventually find enough satellites, lock in on them,
282 and 'ao-view' will both auditorially announce and visually indicate
284 Now you can launch knowing that you have a good data path and
285 good satellite lock for flight data and recovery. Remember
286 you MUST tell ao-view to connect to the TeleDongle explicitly in
287 order for ao-view to be able to receive data.
290 The altimeters provide RDF (radio direction finding) tones on
291 the pad, during descent and after landing. These can be used to
292 locate the rocket using a directional antenna; the signal
293 strength providing an indication of the direction from receiver to rocket.
296 TeleMetrum also provides GPS trekking data, which can further simplify
297 locating the rocket once it has landed. (The last good GPS data
298 received before touch-down will be on the data screen of 'ao-view'.)
301 Once you have recovered the rocket you can download the eeprom
302 contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
303 either a USB cable or over the radio link using TeleDongle.
304 And by following the man page for 'ao-postflight' you can create
305 various data output reports, graphs, and even kml data to see the
306 flight trajectory in google-earth. (Moving the viewing angle making
307 sure to connect the yellow lines while in google-earth is the proper
311 As for ao-view.... some things are in the menu but don't do anything
312 very useful. The developers have stopped working on ao-view to focus
313 on a new, cross-platform ground station program. So ao-view may or
314 may not be updated in the future. Mostly you just use
315 the Log and Device menus. It has a wonderful display of the incoming
316 flight data and I am sure you will enjoy what it has to say to you
317 once you enable the voice output!
322 TeleMetrum seems to shut off when disconnected from the
323 computer. Make sure the battery is adequately charged. Remember the
324 unit will pull more power than the USB port can deliver before the
325 GPS enters "locked" mode. The battery charges best when TeleMetrum
329 It's impossible to stop the TeleDongle when it's in "p" mode, I have
330 to unplug the USB cable? Make sure you have tried to "escape out" of
331 this mode. If this doesn't work the reboot procedure for the
332 TeleDongle *is* to simply unplug it. 'cu' however will retain it's
333 outgoing buffer IF your "escape out" ('~~') does not work.
334 At this point using either 'ao-view' (or possibly
335 'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
339 The amber LED (on the TeleMetrum) lights up when both
340 battery and USB are connected. Does this mean it's charging?
341 Yes, the yellow LED indicates the charging at the 'regular' rate.
342 If the led is out but the unit is still plugged into a USB port,
343 then the battery is being charged at a 'trickle' rate.
346 There are no "dit-dah-dah-dit" sound or lights like the manual mentions?
347 That's the "pad" mode. Weak batteries might be the problem.
348 It is also possible that the Telemetrum is horizontal and the output
349 is instead a "dit-dit" meaning 'idle'. For TeleMini, it's possible that
350 it received a command packet which would have left it in "pad" mode.
353 It's unclear how to use 'ao-view' and other programs when 'cu'
354 is running. You cannot have more than one program connected to
355 the TeleDongle at one time without apparent data loss as the
356 incoming data will not make it to both programs intact.
357 Disconnect whatever programs aren't currently being used.
360 How do I save flight data?
361 Live telemetry is written to file(s) whenever 'ao-view' is connected
362 to the TeleDongle. The file area defaults to ~/altos
363 but is easily changed using the menus in 'ao-view'. The files that
364 are written end in '.telem'. The after-flight
365 data-dumped files will end in .eeprom and represent continuous data
366 unlike the rf-linked .telem files that are subject to the
367 turnarounds/data-packaging time slots in the half-duplex rf data path.
368 See the above instructions on what and how to save the eeprom stored
369 data after physically retrieving your TeleMetrum. Make sure to save
370 the on-board data after each flight, as the current firmware will
371 over-write any previous flight data during a new flight.
376 <title>Specifications</title>
378 <title>TeleMetrum Specifications</title>
382 Recording altimeter for model rocketry.
387 Supports dual deployment (can fire 2 ejection charges).
392 70cm ham-band transceiver for telemetry downlink.
397 Barometric pressure sensor good to 45k feet MSL.
402 1-axis high-g accelerometer for motor characterization, capable of
403 +/- 50g using default part.
408 On-board, integrated GPS receiver with 5hz update rate capability.
413 On-board 1 megabyte non-volatile memory for flight data storage.
418 USB interface for battery charging, configuration, and data recovery.
423 Fully integrated support for LiPo rechargeable batteries.
428 Uses LiPo to fire e-matches, can be modiied to support
429 optional separate pyro battery if needed.
434 2.75 x 1 inch board designed to fit inside 29mm airframe coupler tube.
440 <title>TeleMini Specifications</title>
444 Recording altimeter for model rocketry.
449 Supports dual deployment (can fire 2 ejection charges).
454 70cm ham-band transceiver for telemetry downlink.
459 Barometric pressure sensor good to 45k feet MSL.
464 On-board 5 kilobyte non-volatile memory for flight data storage.
469 RF interface for battery charging, configuration, and data recovery.
474 Support for LiPo rechargeable batteries, using an external charger.
479 Uses LiPo to fire e-matches, can be modiied to support
480 optional separate pyro battery if needed.
485 1.5 x .5 inch board designed to fit inside 18mm airframe coupler tube.
492 <title>Handling Precautions</title>
494 All Altus Metrum products are sophisticated electronic device. When handled gently and
495 properly installed in an airframe, theywill deliver impressive results.
496 However, like all electronic devices, there are some precautions you
500 The Lithium Polymer rechargeable batteries have an
501 extraordinary power density. This is great because we can fly with
502 much less battery mass than if we used alkaline batteries or previous
503 generation rechargeable batteries... but if they are punctured
504 or their leads are allowed to short, they can and will release their
506 Thus we recommend that you take some care when handling our batteries
507 and consider giving them some extra protection in your airframe. We
508 often wrap them in suitable scraps of closed-cell packing foam before
509 strapping them down, for example.
512 The barometric sensor is sensitive to sunlight. In normal
513 mounting situations, it and all of the other surface mount components
514 are "down" towards whatever the underlying mounting surface is, so
515 this is not normally a problem. Please consider this, though, when
516 designing an installation, for example, in an airframe with a
517 see-through plastic payload bay.
520 The barometric sensor sampling port must be able to
522 both by not being covered by foam or tape or other materials that might
523 directly block the hole on the top of the sensor, but also by having a
524 suitable static vent to outside air.
527 As with all other rocketry electronics, Altus Metrum altimeters must be protected
528 from exposure to corrosive motor exhaust and ejection charge gasses.
532 <title>Hardware Overview</title>
534 TeleMetrum is a 1 inch by 2.75 inch circuit board. It was designed to
535 fit inside coupler for 29mm airframe tubing, but using it in a tube that
536 small in diameter may require some creativity in mounting and wiring
537 to succeed! The default 1/4
538 wave UHF wire antenna attached to the center of the nose-cone end of
539 the board is about 7 inches long, and wiring for a power switch and
540 the e-matches for apogee and main ejection charges depart from the
541 fin can end of the board. Given all this, an ideal "simple" avionics
542 bay for TeleMetrum should have at least 10 inches of interior length.
545 TeleMini is a 0.5 inch by 1.5 inch circuit board. It was designed to
546 fit inside an 18mm airframe tube, but using it in a tube that
547 small in diameter may require some creativity in mounting and wiring
548 to succeed! The default 1/4
549 wave UHF wire antenna attached to the center of the nose-cone end of
550 the board is about 7 inches long, and wiring for a power switch and
551 the e-matches for apogee and main ejection charges depart from the
552 fin can end of the board. Given all this, an ideal "simple" avionics
553 bay for TeleMini should have at least 9 inches of interior length.
556 A typical TeleMetrum or TeleMini installation using the on-board devices and
557 default wire UHF antenna involves attaching only a suitable
558 Lithium Polymer battery, a single pole switch for power on/off, and
559 two pairs of wires connecting e-matches for the apogee and main ejection
563 By default, we use the unregulated output of the LiPo battery directly
564 to fire ejection charges. This works marvelously with standard
565 low-current e-matches like the J-Tek from MJG Technologies, and with
566 Quest Q2G2 igniters. However, if you
567 want or need to use a separate pyro battery, check out the "External Pyro Battery"
568 section in this manual for instructions on how to wire that up. The
569 altimeters are designed to work with an external pyro battery of up to 15V.
572 Ejection charges are wired directly to the screw terminal block
573 at the aft end of the altimeter. This is very similar to what
574 most other altimeter vendors provide and so may be the most
575 familiar option. You'll need a very small straight blade
576 screwdriver to connect and disconnect the board in this case,
577 such as you might find in a jeweler's screwdriver set.
580 TeleMetrum also uses the screw terminal block for the power
581 switch leads. On TeleMini, the power switch leads are soldered
582 directly to the board and can be connected directly to the switch.
585 For most airframes, the integrated antennas are more than
586 adequate However, if you are installing in a carbon-fiber
587 electronics bay which is opaque to RF signals, you may need to
588 use off-board external antennas instead. In this case, you can
589 order an altimeter with an SMA connector for the UHF antenna
590 connection, and, on TeleMetrum, you can unplug the integrated GPS
591 antenna and select an appropriate off-board GPS antenna with
592 cable terminating in a U.FL connector.
596 <title>System Operation</title>
598 <title>Firmware Modes </title>
600 The AltOS firmware build for the altimeters has two
601 fundamental modes, "idle" and "flight". Which of these modes
602 the firmware operates in is determined at startup time. For
603 TeleMetrum, the mode is controlled by the orientation of the
604 rocket (well, actually the board, of course...) at the time
605 power is switched on. If the rocket is "nose up", then
606 TeleMetrum assumes it's on a rail or rod being prepared for
607 launch, so the firmware chooses flight mode. However, if the
608 rocket is more or less horizontal, the firmware instead enters
609 idle mode. For TeleMini, "idle" mode is selected when the
610 board receives a command packet within the first five seconds
611 of operation; if no packet is received, the board enters
615 At power on, you will hear three beeps or see three flashes
616 ("S" in Morse code for startup) and then a pause while
617 the altimeter completes initialization and self tests, and decides which
621 In flight or "pad" mode, the altimeter engages the flight
622 state machine, goes into transmit-only mode on the RF link
623 sending telemetry, and waits for launch to be detected.
624 Flight mode is indicated by an "di-dah-dah-dit" ("P" for pad)
625 on the beeper or lights, followed by beeps or flashes
626 indicating the state of the pyrotechnic igniter continuity.
627 One beep/flash indicates apogee continuity, two beeps/flashes
628 indicate main continuity, three beeps/flashes indicate both
629 apogee and main continuity, and one longer "brap" sound or
630 rapidly alternating lights indicates no continuity. For a
631 dual deploy flight, make sure you're getting three beeps or
632 flashes before launching! For apogee-only or motor eject
633 flights, do what makes sense.
636 In idle mode, you will hear an audible "di-dit" or see two short flashes ("I" for idle), and
637 the normal flight state machine is disengaged, thus
638 no ejection charges will fire. The altimeters also listen on the RF
639 link when in idle mode for packet mode requests sent from TeleDongle.
640 Commands can be issued to a TeleMetrum in idle mode over either
641 USB or the RF link equivalently. TeleMini uses only the RF link.
642 Idle mode is useful for configuring the altimeter, for extracting data
643 from the on-board storage chip after flight, and for ground testing
647 One "neat trick" of particular value when the altimeter is used with very
648 large airframes, is that you can power the board up while the rocket
649 is horizontal, such that it comes up in idle mode. Then you can
650 raise the airframe to launch position, use a TeleDongle to open
651 a packet connection, and issue a 'reset' command which will cause
652 the altimeter to reboot and come up in
653 flight mode. This is much safer than standing on the top step of a
654 rickety step-ladder or hanging off the side of a launch tower with
655 a screw-driver trying to turn on your avionics before installing
662 TeleMetrum includes a complete GPS receiver. See a later section for
663 a brief explanation of how GPS works that will help you understand
664 the information in the telemetry stream. The bottom line is that
665 the TeleMetrum GPS receiver needs to lock onto at least four
666 satellites to obtain a solid 3 dimensional position fix and know
670 TeleMetrum provides backup power to the GPS chip any time a LiPo
671 battery is connected. This allows the receiver to "warm start" on
672 the launch rail much faster than if every power-on were a "cold start"
673 for the GPS receiver. In typical operations, powering up TeleMetrum
674 on the flight line in idle mode while performing final airframe
675 preparation will be sufficient to allow the GPS receiver to cold
676 start and acquire lock. Then the board can be powered down during
677 RSO review and installation on a launch rod or rail. When the board
678 is turned back on, the GPS system should lock very quickly, typically
679 long before igniter installation and return to the flight line are
684 <title>Ground Testing </title>
686 An important aspect of preparing a rocket using electronic deployment
687 for flight is ground testing the recovery system. Thanks
688 to the bi-directional RF link central to the Altus Metrum system,
689 this can be accomplished in a TeleMetrum- or TeleMini- equipped rocket without as
690 much work as you may be accustomed to with other systems. It can
694 Just prep the rocket for flight, then power up the altimeter
695 in "idle" mode (placing airframe horizontal for TeleMetrum or
696 starting the RF packet connection for TeleMini). This will cause the
697 firmware to go into "idle" mode, in which the normal flight
698 state machine is disabled and charges will not fire without
699 manual command. Then, establish an RF packet connection from
700 a TeleDongle-equipped computer using the P command from a safe
701 distance. You can now command the altimeter to fire the apogee
702 or main charges to complete your testing.
705 In order to reduce the chance of accidental firing of pyrotechnic
706 charges, the command to fire a charge is intentionally somewhat
707 difficult to type, and the built-in help is slightly cryptic to
708 prevent accidental echoing of characters from the help text back at
709 the board from firing a charge. The command to fire the apogee
710 drogue charge is 'i DoIt drogue' and the command to fire the main
711 charge is 'i DoIt main'.
715 <title>Radio Link </title>
717 The chip our boards are based on incorporates an RF transceiver, but
718 it's not a full duplex system... each end can only be transmitting or
719 receiving at any given moment. So we had to decide how to manage the
723 By design, the altimeter firmware listens for an RF connection when
724 it's in "idle mode", which
725 allows us to use the RF link to configure the rocket, do things like
726 ejection tests, and extract data after a flight without having to
727 crack open the airframe. However, when the board is in "flight
728 mode", the altimeter only
729 transmits and doesn't listen at all. That's because we want to put
730 ultimate priority on event detection and getting telemetry out of
731 the rocket and out over
732 the RF link in case the rocket crashes and we aren't able to extract
736 We don't use a 'normal packet radio' mode because they're just too
737 inefficient. The GFSK modulation we use is just FSK with the
738 baseband pulses passed through a
739 Gaussian filter before they go into the modulator to limit the
740 transmitted bandwidth. When combined with the hardware forward error
741 correction support in the cc1111 chip, this allows us to have a very
742 robust 38.4 kilobit data link with only 10 milliwatts of transmit power,
743 a whip antenna in the rocket, and a hand-held Yagi on the ground. We've
744 had flights to above 21k feet AGL with good reception, and calculations
745 suggest we should be good to well over 40k feet AGL with a 5-element yagi on
746 the ground. We hope to fly boards to higher altitudes soon, and would
747 of course appreciate customer feedback on performance in higher
752 <title>Configurable Parameters</title>
754 Configuring an Altus Metrum altimeter for flight is very
755 simple. Through the use of a Kalman filter, there is no need
756 to set a "mach delay" . The few configurable parameters can
757 all be set using a simple terminal program over the USB port
758 or RF link via TeleDongle.
761 <title>Radio Frequencies</title>
763 The Altus Metrum boards support frequencies in the 70cm
764 band. By default, the configuration interface provides a
765 list of 10 common frequencies -- 100kHz channels starting at
766 434.550MHz. However, you can configure the firmware to use
767 any 50kHz multiple within the 70cm band. At any given
768 launch, we highly recommend coordinating who will use each
769 frequency and when to avoid interference. And of course, both
770 altimeter and TeleDongle must be configured to the same
771 frequency to successfully communicate with each other.
774 To set the radio frequency, use the 'c R' command to specify the
775 radio transceiver configuration parameter. This parameter is computed
776 using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and
777 the standard calibration reference frequency, 'S', (normally 434.550Mhz):
781 Round the result to the nearest integer value.
782 As with all 'c' sub-commands, follow this with a 'c w' to write the
783 change to the parameter block in the on-board flash on
784 your altimeter board if you want the change to stay in place across reboots.
788 <title>Apogee Delay</title>
790 Apogee delay is the number of seconds after the altimeter detects flight
791 apogee that the drogue charge should be fired. In most cases, this
792 should be left at the default of 0. However, if you are flying
793 redundant electronics such as for an L3 certification, you may wish
794 to set one of your altimeters to a positive delay so that both
795 primary and backup pyrotechnic charges do not fire simultaneously.
798 To set the apogee delay, use the 'c d' command.
799 As with all 'c' sub-commands, follow this with a 'c w' to write the
800 change to the parameter block in the on-board DataFlash chip.
803 Please note that the Altus Metrum apogee detection algorithm
804 fires exactly at apogee. If you are also flying an
805 altimeter like the PerfectFlite MAWD, which only supports
806 selecting 0 or 1 seconds of apogee delay, you may wish to
807 set the MAWD to 0 seconds delay and set the TeleMetrum to
808 fire your backup 2 or 3 seconds later to avoid any chance of
809 both charges firing simultaneously. We've flown several
810 airframes this way quite happily, including Keith's
815 <title>Main Deployment Altitude</title>
817 By default, the altimeter will fire the main deployment charge at an
818 elevation of 250 meters (about 820 feet) above ground. We think this
819 is a good elevation for most airframes, but feel free to change this
820 to suit. In particular, if you are flying two altimeters, you may
822 deployment elevation for the backup altimeter to be something lower
823 than the primary so that both pyrotechnic charges don't fire
827 To set the main deployment altitude, use the 'c m' command.
828 As with all 'c' sub-commands, follow this with a 'c w' to write the
829 change to the parameter block in the on-board DataFlash chip.
834 <title>Calibration</title>
836 There are only two calibrations required for a TeleMetrum board, and
837 only one for TeleDongle and TeleMini.
840 <title>Radio Frequency</title>
842 The radio frequency is synthesized from a clock based on the 48 Mhz
843 crystal on the board. The actual frequency of this oscillator must be
844 measured to generate a calibration constant. While our GFSK modulation
845 bandwidth is wide enough to allow boards to communicate even when
846 their oscillators are not on exactly the same frequency, performance
847 is best when they are closely matched.
848 Radio frequency calibration requires a calibrated frequency counter.
849 Fortunately, once set, the variation in frequency due to aging and
850 temperature changes is small enough that re-calibration by customers
851 should generally not be required.
854 To calibrate the radio frequency, connect the UHF antenna port to a
855 frequency counter, set the board to 434.550MHz, and use the 'C'
856 command to generate a CW carrier. Wait for the transmitter temperature
857 to stabilize and the frequency to settle down.
858 Then, divide 434.550 Mhz by the
859 measured frequency and multiply by the current radio cal value show
860 in the 'c s' command. For an unprogrammed board, the default value
861 is 1186611. Take the resulting integer and program it using the 'c f'
862 command. Testing with the 'C' command again should show a carrier
863 within a few tens of Hertz of the intended frequency.
864 As with all 'c' sub-commands, follow this with a 'c w' to write the
865 change to the parameter block in the on-board DataFlash chip.
868 when the radio calibration value is changed, the radio
869 frequency value is reset to the same value, so you'll need
870 to recompute and reset the radio frequency value using the
871 new radio calibration value.
875 <title>TeleMetrum Accelerometer</title>
877 The TeleMerum accelerometer we use has its own 5 volt power supply and
878 the output must be passed through a resistive voltage divider to match
879 the input of our 3.3 volt ADC. This means that unlike the barometric
880 sensor, the output of the acceleration sensor is not ratiometric to
881 the ADC converter, and calibration is required. We also support the
882 use of any of several accelerometers from a Freescale family that
883 includes at least +/- 40g, 50g, 100g, and 200g parts. Using gravity,
884 a simple 2-point calibration yields acceptable results capturing both
885 the different sensitivities and ranges of the different accelerometer
886 parts and any variation in power supply voltages or resistor values
887 in the divider network.
890 To calibrate the acceleration sensor, use the 'c a 0' command. You
891 will be prompted to orient the board vertically with the UHF antenna
892 up and press a key, then to orient the board vertically with the
893 UHF antenna down and press a key.
894 As with all 'c' sub-commands, follow this with a 'c w' to write the
895 change to the parameter block in the on-board DataFlash chip.
898 The +1g and -1g calibration points are included in each telemetry
899 frame and are part of the header extracted by ao-dumplog after flight.
900 Note that we always store and return raw ADC samples for each
901 sensor... nothing is permanently "lost" or "damaged" if the
905 In the unlikely event an accel cal that goes badly, it is possible
906 that TeleMetrum may always come up in 'pad mode' and as such not be
907 listening to either the USB or radio interfaces. If that happens,
908 there is a special hook in the firmware to force the board back
909 in to 'idle mode' so you can re-do the cal. To use this hook, you
910 just need to ground the SPI clock pin at power-on. This pin is
911 available as pin 2 on the 8-pin companion connector, and pin 1 is
912 ground. So either carefully install a fine-gauge wire jumper
913 between the two pins closest to the index hole end of the 8-pin
914 connector, or plug in the programming cable to the 8-pin connector
915 and use a small screwdriver or similar to short the two pins closest
916 to the index post on the 4-pin end of the programming cable, and
917 power up the board. It should come up in 'idle mode' (two beeps).
925 <title>Updating Device Firmware</title>
927 The big conceptual thing to realize is that you have to use a
928 TeleDongle as a programmer to update a TeleMetrum or TeleMini,
929 and a TeleMetrum or other TeleDongle to program the TeleDongle
930 Due to limited memory resources in the cc1111, we don't support
931 programming directly over USB.
934 You may wish to begin by ensuring you have current firmware images.
935 These are distributed as part of the AltOS software bundle that
936 also includes the AltosUI ground station program. Newer ground
937 station versions typically work fine with older firmware versions,
938 so you don't need to update your devices just to try out new
939 software features. You can always download the most recent
940 version from <ulink url="http://www.altusmetrum.org/AltOS/"/>.
943 We recommend updating the altimeter first, before updating TeleDongle.
946 <title>Updating TeleMetrum Firmware</title>
947 <orderedlist inheritnum='inherit' numeration='arabic'>
949 Find the 'programming cable' that you got as part of the starter
950 kit, that has a red 8-pin MicroMaTch connector on one end and a
951 red 4-pin MicroMaTch connector on the other end.
954 Take the 2 screws out of the TeleDongle case to get access
955 to the circuit board.
958 Plug the 8-pin end of the programming cable to the
959 matching connector on the TeleDongle, and the 4-pin end to the
960 matching connector on the TeleMetrum.
961 Note that each MicroMaTch connector has an alignment pin that
962 goes through a hole in the PC board when you have the cable
966 Attach a battery to the TeleMetrum board.
969 Plug the TeleDongle into your computer's USB port, and power
973 Run AltosUI, and select 'Flash Image' from the File menu.
976 Pick the TeleDongle device from the list, identifying it as the
980 Select the image you want put on the TeleMetrum, which should have a
981 name in the form telemetrum-v1.1-1.0.0.ihx. It should be visible
982 in the default directory, if not you may have to poke around
983 your system to find it.
986 Make sure the configuration parameters are reasonable
987 looking. If the serial number and/or RF configuration
988 values aren't right, you'll need to change them.
991 Hit the 'OK' button and the software should proceed to flash
992 the TeleMetrum with new firmware, showing a progress bar.
995 Confirm that the TeleMetrum board seems to have updated ok, which you
996 can do by plugging in to it over USB and using a terminal program
997 to connect to the board and issue the 'v' command to check
1001 If something goes wrong, give it another try.
1006 <title>Updating TeleMini Firmware</title>
1007 <orderedlist inheritnum='inherit' numeration='arabic'>
1009 You'll need a special 'programming cable' to reprogram the
1010 TeleMini. It's available on the Altus Metrum web store, or
1011 you can make your own using an 8-pin MicroMaTch connector on
1012 one end and a set of four pins on the other.
1015 Take the 2 screws out of the TeleDongle case to get access
1016 to the circuit board.
1019 Plug the 8-pin end of the programming cable to the matching
1020 connector on the TeleDongle, and the 4-pins into the holes
1021 in the TeleMini circuit board. Note that the MicroMaTch
1022 connector has an alignment pin that goes through a hole in
1023 the PC board when you have the cable oriented correctly, and
1024 that pin 1 on the TeleMini board is marked with a square pad
1025 while the other pins have round pads.
1028 Attach a battery to the TeleMini board.
1031 Plug the TeleDongle into your computer's USB port, and power
1035 Run AltosUI, and select 'Flash Image' from the File menu.
1038 Pick the TeleDongle device from the list, identifying it as the
1042 Select the image you want put on the TeleMini, which should have a
1043 name in the form telemini-v1.0-1.0.0.ihx. It should be visible
1044 in the default directory, if not you may have to poke around
1045 your system to find it.
1048 Make sure the configuration parameters are reasonable
1049 looking. If the serial number and/or RF configuration
1050 values aren't right, you'll need to change them.
1053 Hit the 'OK' button and the software should proceed to flash
1054 the TeleMini with new firmware, showing a progress bar.
1057 Confirm that the TeleMini board seems to have updated ok, which you
1058 can do by configuring it over the RF link through the TeleDongle, or
1059 letting it come up in "flight" mode and listening for telemetry.
1062 If something goes wrong, give it another try.
1067 <title>Updating TeleDongle Firmware</title>
1069 Updating TeleDongle's firmware is just like updating TeleMetrum or TeleMini
1070 firmware, but you use either a TeleMetrum or another TeleDongle as the programmer.
1072 <orderedlist inheritnum='inherit' numeration='arabic'>
1074 Find the 'programming cable' that you got as part of the starter
1075 kit, that has a red 8-pin MicroMaTch connector on one end and a
1076 red 4-pin MicroMaTch connector on the other end.
1079 Find the USB cable that you got as part of the starter kit, and
1080 plug the "mini" end in to the mating connector on TeleMetrum or TeleDongle.
1083 Take the 2 screws out of the TeleDongle case to get access
1084 to the circuit board.
1087 Plug the 8-pin end of the programming cable to the
1088 matching connector on the programmer, and the 4-pin end to the
1089 matching connector on the TeleDongle.
1090 Note that each MicroMaTch connector has an alignment pin that
1091 goes through a hole in the PC board when you have the cable
1095 Attach a battery to the TeleMetrum board if you're using one.
1098 Plug both the programmer and the TeleDongle into your computer's USB
1099 ports, and power up the programmer.
1102 Run AltosUI, and select 'Flash Image' from the File menu.
1105 Pick the programmer device from the list, identifying it as the
1109 Select the image you want put on the TeleDongle, which should have a
1110 name in the form teledongle-v0.2-1.0.0.ihx. It should be visible
1111 in the default directory, if not you may have to poke around
1112 your system to find it.
1115 Make sure the configuration parameters are reasonable
1116 looking. If the serial number and/or RF configuration
1117 values aren't right, you'll need to change them. The TeleDongle
1118 serial number is on the "bottom" of the circuit board, and can
1119 usually be read through the translucent blue plastic case without
1120 needing to remove the board from the case.
1123 Hit the 'OK' button and the software should proceed to flash
1124 the TeleDongle with new firmware, showing a progress bar.
1127 Confirm that the TeleDongle board seems to have updated ok, which you
1128 can do by plugging in to it over USB and using a terminal program
1129 to connect to the board and issue the 'v' command to check
1130 the version, etc. Once you're happy, remove the programming cable
1131 and put the cover back on the TeleDongle.
1134 If something goes wrong, give it another try.
1138 Be careful removing the programming cable from the locking 8-pin
1139 connector on TeleMetrum. You'll need a fingernail or perhaps a thin
1140 screwdriver or knife blade to gently pry the locking ears out
1141 slightly to extract the connector. We used a locking connector on
1142 TeleMetrum to help ensure that the cabling to companion boards
1143 used in a rocket don't ever come loose accidentally in flight.
1151 <title>AltosUI</title>
1153 The AltosUI program provides a graphical user interface for
1154 interacting with the Altus Metrum product family, including
1155 TeleMetrum, TeleMini and TeleDongle. AltosUI can monitor telemetry data,
1156 configure TeleMetrum, TeleMini and TeleDongle devices and many other
1157 tasks. The primary interface window provides a selection of
1158 buttons, one for each major activity in the system. This manual
1159 is split into chapters, each of which documents one of the tasks
1160 provided from the top-level toolbar.
1163 <title>Packet Command Mode</title>
1164 <subtitle>Controlling An Altimeter Over The Radio Link</subtitle>
1166 One of the unique features of the Altus Metrum environment is
1167 the ability to create a two way command link between TeleDongle
1168 and an altimeter using the digital radio transceivers built into
1169 each device. This allows you to interact with the altimeter from
1170 afar, as if it were directly connected to the computer.
1173 Any operation which can be performed with TeleMetrum
1174 can either be done with TeleMetrum directly connected to
1175 the computer via the USB cable, or through the packet
1176 link. Simply select the appropriate TeleDongle device when
1177 the list of devices is presented and AltosUI will use packet
1181 One oddity in the current interface is how AltosUI selects the
1182 frequency for packet mode communications. Instead of providing
1183 an interface to specifically configure the frequency, it uses
1184 whatever frequency was most recently selected for the target
1185 TeleDongle device in Monitor Flight mode. If you haven't ever
1186 used that mode with the TeleDongle in question, select the
1187 Monitor Flight button from the top level UI, pick the
1188 appropriate TeleDongle device. Once the flight monitoring
1189 window is open, select the desired frequency and then close it
1190 down again. All Packet Command Mode operations will now use
1196 Save Flight Data—Recover flight data from the rocket without
1202 Configure altimeter apogee delays or main deploy heights
1203 to respond to changing launch conditions. You can also
1204 'reboot' the altimeter. Use this to remotely enable the
1205 flight computer by turning TeleMetrum on in "idle" mode,
1206 then once the airframe is oriented for launch, you can
1207 reboot the altimeter and have it restart in pad mode
1208 without having to climb the scary ladder.
1213 Fire Igniters—Test your deployment charges without snaking
1214 wires out through holes in the airframe. Simply assembly the
1215 rocket as if for flight with the apogee and main charges
1216 loaded, then remotely command the altimeter to fire the
1222 Packet command mode uses the same RF frequencies as telemetry
1223 mode. Configure the desired TeleDongle frequency using the
1224 flight monitor window frequency selector and then close that
1225 window before performing the desired operation.
1228 TeleMetrum only enables packet command mode in 'idle' mode, so
1229 make sure you have TeleMetrum lying horizontally when you turn
1230 it on. Otherwise, TeleMetrum will start in 'pad' mode ready for
1231 flight and will not be listening for command packets from TeleDongle.
1234 TeleMini listens for a command packet for five seconds after
1235 first being turned on, if it doesn't hear anything, it enters
1236 'pad' mode, ready for flight and will no longer listen for
1240 When packet command mode is enabled, you can monitor the link
1241 by watching the lights on the
1242 devices. The red LED will flash each time they
1243 transmit a packet while the green LED will light up
1244 on TeleDongle while it is waiting to receive a packet from
1249 <title>Monitor Flight</title>
1250 <subtitle>Receive, Record and Display Telemetry Data</subtitle>
1252 Selecting this item brings up a dialog box listing all of the
1253 connected TeleDongle devices. When you choose one of these,
1254 AltosUI will create a window to display telemetry data as
1255 received by the selected TeleDongle device.
1258 All telemetry data received are automatically recorded in
1259 suitable log files. The name of the files includes the current
1260 date and rocket serial and flight numbers.
1263 The radio frequency being monitored by the TeleDongle device is
1264 displayed at the top of the window. You can configure the
1265 frequecy by clicking on the frequency box and selecting the desired
1266 frequency. AltosUI remembers the last frequency selected for each
1267 TeleDongle and selects that automatically the next time you use
1271 Below the TeleDongle frequency selector, the window contains a few
1272 significant pieces of information about the altimeter providing
1273 the telemetry data stream:
1277 <para>The configured callsign</para>
1280 <para>The device serial number</para>
1283 <para>The flight number. Each altimeter remembers how many
1289 The rocket flight state. Each flight passes through several
1290 states including Pad, Boost, Fast, Coast, Drogue, Main and
1296 The Received Signal Strength Indicator value. This lets
1297 you know how strong a signal TeleDongle is receiving. The
1298 radio inside TeleDongle operates down to about -99dBm;
1299 weaker signals may not be receiveable. The packet link uses
1300 error correction and detection techniques which prevent
1301 incorrect data from being reported.
1306 Finally, the largest portion of the window contains a set of
1307 tabs, each of which contain some information about the rocket.
1308 They're arranged in 'flight order' so that as the flight
1309 progresses, the selected tab automatically switches to display
1310 data relevant to the current state of the flight. You can select
1311 other tabs at any time. The final 'table' tab contains all of
1312 the telemetry data in one place.
1315 <title>Launch Pad</title>
1317 The 'Launch Pad' tab shows information used to decide when the
1318 rocket is ready for flight. The first elements include red/green
1319 indicators, if any of these is red, you'll want to evaluate
1320 whether the rocket is ready to launch:
1324 Battery Voltage. This indicates whether the LiPo battery
1325 powering the TeleMetrum has sufficient charge to last for
1326 the duration of the flight. A value of more than
1327 3.7V is required for a 'GO' status.
1332 Apogee Igniter Voltage. This indicates whether the apogee
1333 igniter has continuity. If the igniter has a low
1334 resistance, then the voltage measured here will be close
1335 to the LiPo battery voltage. A value greater than 3.2V is
1336 required for a 'GO' status.
1341 Main Igniter Voltage. This indicates whether the main
1342 igniter has continuity. If the igniter has a low
1343 resistance, then the voltage measured here will be close
1344 to the LiPo battery voltage. A value greater than 3.2V is
1345 required for a 'GO' status.
1350 GPS Locked. For a TeleMetrum device, this indicates whether the GPS receiver is
1351 currently able to compute position information. GPS requires
1352 at least 4 satellites to compute an accurate position.
1357 GPS Ready. For a TeleMetrum device, this indicates whether GPS has reported at least
1358 10 consecutive positions without losing lock. This ensures
1359 that the GPS receiver has reliable reception from the
1365 The LaunchPad tab also shows the computed launch pad position
1366 and altitude, averaging many reported positions to improve the
1367 accuracy of the fix.
1372 <title>Ascent</title>
1374 This tab is shown during Boost, Fast and Coast
1375 phases. The information displayed here helps monitor the
1376 rocket as it heads towards apogee.
1379 The height, speed and acceleration are shown along with the
1380 maxium values for each of them. This allows you to quickly
1381 answer the most commonly asked questions you'll hear during
1385 The current latitude and longitude reported by the TeleMetrum GPS are
1386 also shown. Note that under high acceleration, these values
1387 may not get updated as the GPS receiver loses position
1388 fix. Once the rocket starts coasting, the receiver should
1389 start reporting position again.
1392 Finally, the current igniter voltages are reported as in the
1393 Launch Pad tab. This can help diagnose deployment failures
1394 caused by wiring which comes loose under high acceleration.
1398 <title>Descent</title>
1400 Once the rocket has reached apogee and (we hope) activated the
1401 apogee charge, attention switches to tracking the rocket on
1402 the way back to the ground, and for dual-deploy flights,
1403 waiting for the main charge to fire.
1406 To monitor whether the apogee charge operated correctly, the
1407 current descent rate is reported along with the current
1408 height. Good descent rates generally range from 15-30m/s.
1411 For TeleMetrum altimeters, you can locate the rocket in the sky
1412 using the elevation and
1413 bearing information to figure out where to look. Elevation is
1414 in degrees above the horizon. Bearing is reported in degrees
1415 relative to true north. Range can help figure out how big the
1416 rocket will appear. Note that all of these values are relative
1417 to the pad location. If the elevation is near 90°, the rocket
1418 is over the pad, not over you.
1421 Finally, the igniter voltages are reported in this tab as
1422 well, both to monitor the main charge as well as to see what
1423 the status of the apogee charge is.
1427 <title>Landed</title>
1429 Once the rocket is on the ground, attention switches to
1430 recovery. While the radio signal is generally lost once the
1431 rocket is on the ground, the last reported GPS position is
1432 generally within a short distance of the actual landing location.
1435 The last reported GPS position is reported both by
1436 latitude and longitude as well as a bearing and distance from
1437 the launch pad. The distance should give you a good idea of
1438 whether you'll want to walk or hitch a ride. Take the reported
1439 latitude and longitude and enter them into your handheld GPS
1440 unit and have that compute a track to the landing location.
1443 Both TeleMini and TeleMetrum will continue to transmit RDF
1444 tones after landing, allowing you to locate the rocket by
1445 following the radio signal. You may need to get away from
1446 the clutter of the flight line, or even get up on a hill (or
1447 your neighbor's RV) to receive the RDF signal.
1450 Finally, the maximum height, speed and acceleration reported
1451 during the flight are displayed for your admiring observers.
1455 <title>Site Map</title>
1457 When the TeleMetrum gets a GPS fix, the Site Map tab will map
1458 the rocket's position to make it easier for you to locate the
1459 rocket, both while it is in the air, and when it has landed. The
1460 rocket's state is indicated by colour: white for pad, red for
1461 boost, pink for fast, yellow for coast, light blue for drogue,
1462 dark blue for main, and black for landed.
1465 The map's scale is approximately 3m (10ft) per pixel. The map
1466 can be dragged using the left mouse button. The map will attempt
1467 to keep the rocket roughly centred while data is being received.
1470 Images are fetched automatically via the Google Maps Static API,
1471 and are cached for reuse. If map images cannot be downloaded,
1472 the rocket's path will be traced on a dark grey background
1476 You can pre-load images for your favorite launch sites
1477 before you leave home; check out the 'Preload Maps' section below.
1482 <title>Save Flight Data</title>
1484 The altimeter records flight data to its internal flash memory.
1485 The TeleMetrum data is recorded at a much higher rate than the telemetry
1486 system can handle, and is not subject to radio drop-outs. As
1487 such, it provides a more complete and precise record of the
1488 flight. The 'Save Flight Data' button allows you to read the
1489 flash memory and write it to disk. As TeleMini has only a barometer, it
1490 records data at the same rate as the telemetry signal, but there will be
1491 no data lost due to telemetry drop-outs.
1494 Clicking on the 'Save Flight Data' button brings up a list of
1495 connected TeleMetrum and TeleDongle devices. If you select a
1496 TeleMetrum device, the flight data will be downloaded from that
1497 device directly. If you select a TeleDongle device, flight data
1498 will be downloaded from a TeleMetrum or TeleMini device connected via the
1499 packet command link to the specified TeleDongle. See the chapter
1500 on Packet Command Mode for more information about this.
1503 After the device has been selected, a dialog showing the
1504 flight data saved in the device will be shown allowing you to
1505 select which flights to download and which to delete. With
1506 version 0.9 or newer firmware, you must erase flights in order
1507 for the space they consume to be reused by another
1508 flight. This prevents you from accidentally losing flight data
1509 if you neglect to download data before flying again. Note that
1510 if there is no more space available in the device, then no
1511 data will be recorded for a flight.
1514 The filename for each flight log is computed automatically
1515 from the recorded flight date, altimeter serial number and
1516 flight number information.
1520 <title>Replay Flight</title>
1522 Select this button and you are prompted to select a flight
1523 record file, either a .telem file recording telemetry data or a
1524 .eeprom file containing flight data saved from the altimeter
1528 Once a flight record is selected, the flight monitor interface
1529 is displayed and the flight is re-enacted in real time. Check
1530 the Monitor Flight chapter above to learn how this window operates.
1534 <title>Graph Data</title>
1536 Select this button and you are prompted to select a flight
1537 record file, either a .telem file recording telemetry data or a
1538 .eeprom file containing flight data saved from
1542 Once a flight record is selected, the acceleration (blue),
1543 velocity (green) and altitude (red) of the flight are plotted and
1544 displayed, measured in metric units.
1547 The graph can be zoomed into a particular area by clicking and
1548 dragging down and to the right. Once zoomed, the graph can be
1549 reset by clicking and dragging up and to the left. Holding down
1550 control and clicking and dragging allows the graph to be panned.
1551 The right mouse button causes a popup menu to be displayed, giving
1552 you the option save or print the plot.
1555 Note that telemetry files will generally produce poor graphs
1556 due to the lower sampling rate and missed telemetry packets.
1557 Use saved flight data for graphing where possible.
1561 <title>Export Data</title>
1563 This tool takes the raw data files and makes them available for
1564 external analysis. When you select this button, you are prompted to select a flight
1565 data file (either .eeprom or .telem will do, remember that
1566 .eeprom files contain higher resolution and more continuous
1567 data). Next, a second dialog appears which is used to select
1568 where to write the resulting file. It has a selector to choose
1569 between CSV and KML file formats.
1572 <title>Comma Separated Value Format</title>
1574 This is a text file containing the data in a form suitable for
1575 import into a spreadsheet or other external data analysis
1576 tool. The first few lines of the file contain the version and
1577 configuration information from the altimeter, then
1578 there is a single header line which labels all of the
1579 fields. All of these lines start with a '#' character which
1580 most tools can be configured to skip over.
1583 The remaining lines of the file contain the data, with each
1584 field separated by a comma and at least one space. All of
1585 the sensor values are converted to standard units, with the
1586 barometric data reported in both pressure, altitude and
1587 height above pad units.
1591 <title>Keyhole Markup Language (for Google Earth)</title>
1593 This is the format used by
1594 Googleearth to provide an overlay within that
1595 application. With this, you can use Googleearth to see the
1596 whole flight path in 3D.
1601 <title>Configure Altimeter</title>
1603 Select this button and then select either a TeleMetrum or
1604 TeleDongle Device from the list provided. Selecting a TeleDongle
1605 device will use Packet Comamnd Mode to configure a remote
1606 altimeter. Learn how to use this in the Packet Command
1610 The first few lines of the dialog provide information about the
1611 connected device, including the product name,
1612 software version and hardware serial number. Below that are the
1613 individual configuration entries.
1616 At the bottom of the dialog, there are four buttons:
1621 Save. This writes any changes to the
1622 configuration parameter block in flash memory. If you don't
1623 press this button, any changes you make will be lost.
1628 Reset. This resets the dialog to the most recently saved values,
1629 erasing any changes you have made.
1634 Reboot. This reboots the device. Use this to
1635 switch from idle to pad mode by rebooting once the rocket is
1636 oriented for flight.
1641 Close. This closes the dialog. Any unsaved changes will be
1647 The rest of the dialog contains the parameters to be configured.
1650 <title>Main Deploy Altitude</title>
1652 This sets the altitude (above the recorded pad altitude) at
1653 which the 'main' igniter will fire. The drop-down menu shows
1654 some common values, but you can edit the text directly and
1655 choose whatever you like. If the apogee charge fires below
1656 this altitude, then the main charge will fire two seconds
1657 after the apogee charge fires.
1661 <title>Apogee Delay</title>
1663 When flying redundant electronics, it's often important to
1664 ensure that multiple apogee charges don't fire at precisely
1665 the same time as that can overpressurize the apogee deployment
1666 bay and cause a structural failure of the airframe. The Apogee
1667 Delay parameter tells the flight computer to fire the apogee
1668 charge a certain number of seconds after apogee has been
1673 <title>Radio Frequency</title>
1675 This configures which of the configured frequencies to use for both
1676 telemetry and packet command mode. Note that if you set this
1677 value via packet command mode, you will have to reconfigure
1678 the TeleDongle frequency before you will be able to use packet
1683 <title>Radio Calibration</title>
1685 The radios in every Altus Metrum device are calibrated at the
1686 factory to ensure that they transmit and receive on the
1687 specified frequency. You can adjust that
1688 calibration by changing this value. To change the TeleDongle's
1689 calibration, you must reprogram the unit completely.
1693 <title>Callsign</title>
1695 This sets the callsign included in each telemetry packet. Set this
1696 as needed to conform to your local radio regulations.
1700 <title>Maximum Flight Log Size</title>
1702 This sets the space (in kilobytes) allocated for each flight
1703 log. The available space will be divided into chunks of this
1704 size. A smaller value will allow more flights to be stored,
1705 a larger value will record data from longer flights.
1708 During ascent, TeleMetrum records barometer and
1709 accelerometer values 100 times per second, other analog
1710 information (voltages and temperature) 6 times per second
1711 and GPS data once per second. During descent, the non-GPS
1712 data is recorded 1/10th as often. Each barometer +
1713 accelerometer record takes 8 bytes.
1716 The default, 192kB, will store over 200 seconds of data at
1717 the ascent rate, or over 2000 seconds of data at the descent
1718 rate. That's plenty for most flights. This leaves enough
1719 storage for five flights in a 1MB system, or 10 flights in a
1723 The configuration block takes the last available block of
1724 memory, on v1.0 boards that's just 256 bytes. However, the
1725 flash part on the v1.1 boards uses 64kB for each block.
1728 TeleMini has 5kB of on-board storage, which is plenty for a
1729 single flight. Make sure you download and delete the data
1730 before a subsequent flight or it will not log any data.
1735 <title>Configure AltosUI</title>
1737 This button presents a dialog so that you can configure the AltosUI global settings.
1740 <title>Voice Settings</title>
1742 AltosUI provides voice annoucements during flight so that you
1743 can keep your eyes on the sky and still get information about
1744 the current flight status. However, sometimes you don't want
1749 <para>Enable—turns all voice announcements on and off</para>
1753 Test Voice—Plays a short message allowing you to verify
1754 that the audio systme is working and the volume settings
1761 <title>Log Directory</title>
1763 AltosUI logs all telemetry data and saves all TeleMetrum flash
1764 data to this directory. This directory is also used as the
1765 staring point when selecting data files for display or export.
1768 Click on the directory name to bring up a directory choosing
1769 dialog, select a new directory and click 'Select Directory' to
1770 change where AltosUI reads and writes data files.
1774 <title>Callsign</title>
1776 This value is used in command packet mode and is transmitted
1777 in each packet sent from TeleDongle and received from
1778 TeleMetrum. It is not used in telemetry mode as that transmits
1779 packets only from TeleMetrum to TeleDongle. Configure this
1780 with the AltosUI operators callsign as needed to comply with
1781 your local radio regulations.
1785 <title>Serial Debug</title>
1787 This causes all communication with a connected device to be
1788 dumped to the console from which AltosUI was started. If
1789 you've started it from an icon or menu entry, the output
1790 will simply be discarded. This mode can be useful to debug
1791 various serial communication issues.
1795 <title>Manage Frequencies</title>
1797 This brings up a dialog where you can configure the set of
1798 frequencies shown in the various frequency menus. You can
1799 add as many as you like, or even reconfigure the default
1800 set. Changing this list does not affect the frequency
1801 settings of any devices, it only changes the set of
1802 frequencies shown in the menus.
1807 <title>Flash Image</title>
1809 This reprograms any Altus Metrum device by using a TeleMetrum or
1810 TeleDongle as a programming dongle. Please read the directions
1811 for connecting the programming cable in the main TeleMetrum
1812 manual before reading these instructions.
1815 Once you have the programmer and target devices connected,
1816 push the 'Flash Image' button. That will present a dialog box
1817 listing all of the connected devices. Carefully select the
1818 programmer device, not the device to be programmed.
1821 Next, select the image to flash to the device. These are named
1822 with the product name and firmware version. The file selector
1823 will start in the directory containing the firmware included
1824 with the AltosUI package. Navigate to the directory containing
1825 the desired firmware if it isn't there.
1828 Next, a small dialog containing the device serial number and
1829 RF calibration values should appear. If these values are
1830 incorrect (possibly due to a corrupted image in the device),
1831 enter the correct values here.
1834 Finally, a dialog containing a progress bar will follow the
1835 programming process.
1838 When programming is complete, the target device will
1839 reboot. Note that if the target device is connected via USB, you
1840 will have to unplug it and then plug it back in for the USB
1841 connection to reset so that you can communicate with the device
1846 <title>Fire Igniter</title>
1848 This activates the igniter circuits in TeleMetrum to help test
1849 recovery systems deployment. Because this command can operate
1850 over the Packet Command Link, you can prepare the rocket as
1851 for flight and then test the recovery system without needing
1852 to snake wires inside the airframe.
1855 Selecting the 'Fire Igniter' button brings up the usual device
1856 selection dialog. Pick the desired TeleDongle or TeleMetrum
1857 device. This brings up another window which shows the current
1858 continutity test status for both apogee and main charges.
1861 Next, select the desired igniter to fire. This will enable the
1865 Select the 'Arm' button. This enables the 'Fire' button. The
1866 word 'Arm' is replaced by a countdown timer indicating that
1867 you have 10 seconds to press the 'Fire' button or the system
1868 will deactivate, at which point you start over again at
1869 selecting the desired igniter.
1873 <title>Scan Channels</title>
1875 This listens for telemetry packets on all of the configured
1876 frequencies, displaying information about each device it
1877 receives a packet from. You can select which of the three
1878 telemetry formats should be tried; by default, it only listens
1879 for the standard telemetry packets used in v1.0 and later
1884 <title>Load Maps</title>
1886 Before heading out to a new launch site, you can use this to
1887 load satellite images in case you don't have internet
1888 connectivity at the site. This loads a fairly large area
1889 around the launch site, which should cover any flight you're likely to make.
1892 There's a drop-down menu of launch sites we know about; if
1893 your favorites aren't there, please let us know the lat/lon
1894 and name of the site. The contents of this list are actually
1895 downloaded at run-time, so as new sites are sent in, they'll
1896 get automatically added to this list.
1899 If the launch site isn't in the list, you can manually enter the lat/lon values
1902 Clicking the 'Load Map' button will fetch images from Google
1903 Maps; note that Google limits how many images you can fetch at
1904 once, so if you load more than one launch site, you may get
1905 some gray areas in the map which indicate that Google is tired
1906 of sending data to you. Try again later.
1910 <title>Monitor Idle</title>
1912 This brings up a dialog similar to the Monitor Flight UI,
1913 except it works with the altimeter in "idle" mode by sending
1914 query commands to discover the current state rather than
1915 listening for telemetry packets.
1920 <title>Using Altus Metrum Products</title>
1922 <title>Being Legal</title>
1924 First off, in the US, you need an <ulink url="http://www.altusmetrum.org/Radio/">amateur radio license</ulink> or
1925 other authorization to legally operate the radio transmitters that are part
1930 <title>In the Rocket</title>
1932 In the rocket itself, you just need a <ulink url="http://www.altusmetrum.org/TeleMetrum/">TeleMetrum</ulink> or
1933 <ulink url="http://www.altusmetrum.org/TeleMini/">TeleMini</ulink> board and
1934 a LiPo rechargeable battery. An 860mAh battery weighs less than a 9V
1935 alkaline battery, and will run a TeleMetrum for hours.
1936 A 110mAh battery weighs less than a triple A battery and will run a TeleMetrum for
1937 a few hours, or a TeleMini for much (much) longer.
1940 By default, we ship the altimeters with a simple wire antenna. If your
1941 electronics bay or the airframe it resides within is made of carbon fiber,
1942 which is opaque to RF signals, you may choose to have an SMA connector
1943 installed so that you can run a coaxial cable to an antenna mounted
1944 elsewhere in the rocket.
1948 <title>On the Ground</title>
1950 To receive the data stream from the rocket, you need an antenna and short
1951 feedline connected to one of our <ulink url="http://www.altusmetrum.org/TeleDongle/">TeleDongle</ulink> units. The
1952 TeleDongle in turn plugs directly into the USB port on a notebook
1953 computer. Because TeleDongle looks like a simple serial port, your computer
1954 does not require special device drivers... just plug it in.
1957 The GUI tool, AltosUI, is written in Java and runs across
1958 Linux, Mac OS and Windows. There's also a suite of C tools
1959 for Linux which can perform most of the same tasks.
1962 After the flight, you can use the RF link to extract the more detailed data
1963 logged in either TeleMetrum or TeleMini devices, or you can use a mini USB cable to plug into the
1964 TeleMetrum board directly. Pulling out the data without having to open up
1965 the rocket is pretty cool! A USB cable is also how you charge the LiPo
1966 battery, so you'll want one of those anyway... the same cable used by lots
1967 of digital cameras and other modern electronic stuff will work fine.
1970 If your TeleMetrum-equiped rocket lands out of sight, you may enjoy having a hand-held GPS
1971 receiver, so that you can put in a waypoint for the last reported rocket
1972 position before touch-down. This makes looking for your rocket a lot like
1973 Geo-Cacheing... just go to the waypoint and look around starting from there.
1976 You may also enjoy having a ham radio "HT" that covers the 70cm band... you
1977 can use that with your antenna to direction-find the rocket on the ground
1978 the same way you can use a Walston or Beeline tracker. This can be handy
1979 if the rocket is hiding in sage brush or a tree, or if the last GPS position
1980 doesn't get you close enough because the rocket dropped into a canyon, or
1981 the wind is blowing it across a dry lake bed, or something like that... Keith
1982 and Bdale both currently own and use the Yaesu VX-7R at launches.
1985 So, to recap, on the ground the hardware you'll need includes:
1986 <orderedlist inheritnum='inherit' numeration='arabic'>
1988 an antenna and feedline
1997 optionally, a handheld GPS receiver
2000 optionally, an HT or receiver covering 435 Mhz
2005 The best hand-held commercial directional antennas we've found for radio
2006 direction finding rockets are from
2007 <ulink url="http://www.arrowantennas.com/" >
2010 The 440-3 and 440-5 are both good choices for finding a
2011 TeleMetrum- or TeleMini- equipped rocket when used with a suitable 70cm HT.
2015 <title>Data Analysis</title>
2017 Our software makes it easy to log the data from each flight, both the
2018 telemetry received over the RF link during the flight itself, and the more
2019 complete data log recorded in the flash memory on the altimeter
2020 board. Once this data is on your computer, our postflight tools make it
2021 easy to quickly get to the numbers everyone wants, like apogee altitude,
2022 max acceleration, and max velocity. You can also generate and view a
2023 standard set of plots showing the altitude, acceleration, and
2024 velocity of the rocket during flight. And you can even export a TeleMetrum data file
2025 useable with Google Maps and Google Earth for visualizing the flight path
2026 in two or three dimensions!
2029 Our ultimate goal is to emit a set of files for each flight that can be
2030 published as a web page per flight, or just viewed on your local disk with
2035 <title>Future Plans</title>
2037 In the future, we intend to offer "companion boards" for the rocket that will
2038 plug in to TeleMetrum to collect additional data, provide more pyro channels,
2039 and so forth. A reference design for a companion board will be documented
2040 soon, and will be compatible with open source Arduino programming tools.
2043 We are also working on the design of a hand-held ground terminal that will
2044 allow monitoring the rocket's status, collecting data during flight, and
2045 logging data after flight without the need for a notebook computer on the
2046 flight line. Particularly since it is so difficult to read most notebook
2047 screens in direct sunlight, we think this will be a great thing to have.
2050 Because all of our work is open, both the hardware designs and the software,
2051 if you have some great idea for an addition to the current Altus Metrum family,
2052 feel free to dive in and help! Or let us know what you'd like to see that
2053 we aren't already working on, and maybe we'll get excited about it too...
projects / fw / altos / blob