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|
<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"/usr/share/xml/docbook/schema/dtd/4.5/docbookx.dtd">
<book>
<title>TeleMetrum</title>
<subtitle>Owner's Manual for the TeleMetrum System</subtitle>
<bookinfo>
<author>
<firstname>Bdale</firstname>
<surname>Garbee</surname>
</author>
<author>
<firstname>Keith</firstname>
<surname>Packard</surname>
</author>
<copyright>
<year>2010</year>
<holder>Bdale Garbee and Keith Packard</holder>
</copyright>
<legalnotice>
<para>
This document is released under the terms of the
<ulink url="http://creativecommons.org/licenses/by-sa/3.0/">
Creative Commons ShareAlike 3.0
</ulink>
license.
</para>
</legalnotice>
<revhistory>
<revision>
<revnumber>0.8</revnumber>
<date>24 November 2010</date>
<revremark>Updated for software version 0.8 </revremark>
</revision>
</revhistory>
</bookinfo>
<chapter>
<title>Introduction and Overview</title>
<para>
Welcome to the Altus Metrum community! Our circuits and software reflect
our passion for both hobby rocketry and Free Software. We hope their
capabilities and performance will delight you in every way, but by
releasing all of our hardware and software designs under open licenses,
we also hope to empower you to take as active a role in our collective
future as you wish!
</para>
<para>
The focal point of our community is TeleMetrum, a dual deploy altimeter
with fully integrated GPS and radio telemetry as standard features, and
a "companion interface" that will support optional capabilities in the
future.
</para>
<para>
Complementing TeleMetrum is TeleDongle, a USB to RF interface for
communicating with TeleMetrum. Combined with your choice of antenna and
notebook computer, TeleDongle and our associated user interface software
form a complete ground station capable of logging and displaying in-flight
telemetry, aiding rocket recovery, then processing and archiving flight
data for analysis and review.
</para>
<para>
More products will be added to the Altus Metrum family over time, and
we currently envision that this will be a single, comprehensive manual
for the entire product family.
</para>
</chapter>
<chapter>
<title>Getting Started</title>
<para>
This chapter began as "The Mere-Mortals Quick Start/Usage Guide to
the Altus Metrum Starter Kit" by Bob Finch, W9YA, NAR 12965, TRA 12350,
w9ya@amsat.org. Bob was one of our first customers for a production
TeleMetrum, and the enthusiasm that led to his contribution of this
section is immensely gratifying and highy appreciated!
</para>
<para>
The first thing to do after you check the inventory of parts in your
"starter kit" is to charge the battery by plugging it into the
corresponding socket of the TeleMetrum and then using the USB A to
mini B
cable to plug the Telemetrum into your computer's USB socket. The
TeleMetrum circuitry will charge the battery whenever it is plugged
in, because the TeleMetrum's on-off switch does NOT control the
charging circuitry. When the GPS chip is initially searching for
satellites, TeleMetrum will consume more current than it can pull
from the usb port, so the battery must be attached in order to get
satellite lock. Once GPS is locked, the current consumption goes back
down enough to enable charging while
running. So it's a good idea to fully charge the battery as your
first item of business so there is no issue getting and maintaining
satellite lock. The yellow charge indicator led will go out when the
battery is nearly full and the charger goes to trickle charge. It
can takeseveral hours to fully recharge a deeply discharged battery.
</para>
<para>
The other active device in the starter kit is the TeleDongle USB to
RF interface. If you plug it in to your Mac or Linux computer it should
"just work", showing up as a serial port device. Windows systems need
driver information that is part of the AltOS download to know that the
existing USB modem driver will work. If you are using Linux and are
having problems, try moving to a fresher kernel (2.6.33 or newer), as
the USB serial driver had ugly bugs in some earlier versions.
</para>
<para>
Next you should obtain and install the AltOS utilities. These include
the AltosUI ground station program, current firmware images for
TeleMetrum and TeleDongle, and a number of standalone utilities that
are rarely needed. Pre-built binary packages are available for Debian
Linux, Microsoft Windows, and recent MacOSX versions. Full sourcecode
and build instructions for some other Linux variants are also available.
The latest version may always be downloaded from
http://altusmetrum.org/AltOS.
</para>
<para>
Both Telemetrum and TeleDongle can be directly communicated
with using USB ports. The first thing you should try after getting
both units plugged into to your computer's usb port(s) is to run
'ao-list' from a terminal-window to see what port-device-name each
device has been assigned by the operating system.
You will need this information to access the devices via their
respective on-board firmware and data using other command line
programs in the AltOS software suite.
</para>
<para>
To access the device's firmware for configuration you need a terminal
program such as you would use to talk to a modem. The software
authors prefer using the program 'cu' which comes from the UUCP package
on most Unix-like systems such as Linux. An example command line for
cu might be 'cu -l /dev/ttyACM0', substituting the correct number
indicated from running the
ao-list program. Another reasonable terminal program for Linux is
'cutecom'. The default 'escape'
character used by CU (i.e. the character you use to
issue commands to cu itself instead of sending the command as input
to the connected device) is a '~'. You will need this for use in
only two different ways during normal operations. First is to exit
the program by sending a '~.' which is called a 'escape-disconnect'
and allows you to close-out from 'cu'. The
second use will be outlined later.
</para>
<para>
Both TeleMetrum and TeleDongle share the concept of a two level
command set in their firmware.
The first layer has several single letter commands. Once
you are using 'cu' (or 'cutecom') sending (typing) a '?'
returns a full list of these
commands. The second level are configuration sub-commands accessed
using the 'c' command, for
instance typing 'c?' will give you this second level of commands
(all of which require the
letter 'c' to access). Please note that most configuration options
are stored only in DataFlash memory, and only TeleMetrum has this
memory to save the various values entered like the channel number
and your callsign when powered off. TeleDongle requires that you
set these each time you plug it in, which ao-view can help with.
</para>
<para>
Try setting these config ('c' or second level menu) values. A good
place to start is by setting your call sign. By default, the boards
use 'N0CALL' which is cute, but not exactly legal!
Spend a few minutes getting comfortable with the units, their
firmware, and 'cu' (or possibly 'cutecom').
For instance, try to send
(type) a 'c r 2' and verify the channel change by sending a 'c s'.
Verify you can connect and disconnect from the units while in your
terminal program by sending the escape-disconnect mentioned above.
</para>
<para>
Note that the 'reboot' command, which is very useful on TeleMetrum,
will likely just cause problems with the dongle. The *correct* way
to reset the dongle is just to unplug and re-plug it.
</para>
<para>
A fun thing to do at the launch site and something you can do while
learning how to use these units is to play with the rf-link access
of the TeleMetrum from the TeleDongle. Be aware that you *must* create
some physical separation between the devices, otherwise the link will
not function due to signal overload in the receivers in each device.
</para>
<para>
Now might be a good time to take a break and read the rest of this
manual, particularly about the two "modes" that the TeleMetrum
can be placed in and how the position of the TeleMetrum when booting
up will determine whether the unit is in "pad" or "idle" mode.
</para>
<para>
You can access a TeleMetrum in idle mode from the Teledongle's USB
connection using the rf link
by issuing a 'p' command to the TeleDongle. Practice connecting and
disconnecting ('~~' while using 'cu') from the TeleMetrum. If
you cannot escape out of the "p" command, (by using a '~~' when in
CU) then it is likely that your kernel has issues. Try a newer version.
</para>
<para>
Using this rf link allows you to configure the TeleMetrum, test
fire e-matches and igniters from the flight line, check pyro-match
continuity and so forth. You can leave the unit turned on while it
is in 'idle mode' and then place the
rocket vertically on the launch pad, walk away and then issue a
reboot command. The TeleMetrum will reboot and start sending data
having changed to the "pad" mode. If the TeleDongle is not receiving
this data, you can disconnect 'cu' from the Teledongle using the
procedures mentioned above and THEN connect to the TeleDongle from
inside 'ao-view'. If this doesn't work, disconnect from the
TeleDongle, unplug it, and try again after plugging it back in.
</para>
<para>
Eventually the GPS will find enough satellites, lock in on them,
and 'ao-view' will both auditorially announce and visually indicate
that GPS is ready.
Now you can launch knowing that you have a good data path and
good satellite lock for flight data and recovery. Remember
you MUST tell ao-view to connect to the TeleDongle explicitly in
order for ao-view to be able to receive data.
</para>
<para>
Both RDF (radio direction finding) tones from the TeleMetrum and
GPS trekking data are available and together are very useful in
locating the rocket once it has landed. (The last good GPS data
received before touch-down will be on the data screen of 'ao-view'.)
</para>
<para>
Once you have recovered the rocket you can download the eeprom
contents using either 'ao-dumplog' (or possibly 'ao-eeprom'), over
either a USB cable or over the radio link using TeleDongle.
And by following the man page for 'ao-postflight' you can create
various data output reports, graphs, and even kml data to see the
flight trajectory in google-earth. (Moving the viewing angle making
sure to connect the yellow lines while in google-earth is the proper
technique.)
</para>
<para>
As for ao-view.... some things are in the menu but don't do anything
very useful. The developers have stopped working on ao-view to focus
on a new, cross-platform ground station program. So ao-view may or
may not be updated in the future. Mostly you just use
the Log and Device menus. It has a wonderful display of the incoming
flight data and I am sure you will enjoy what it has to say to you
once you enable the voice output!
</para>
<section>
<title>FAQ</title>
<para>
The altimeter (TeleMetrum) seems to shut off when disconnected from the
computer. Make sure the battery is adequately charged. Remember the
unit will pull more power than the USB port can deliver before the
GPS enters "locked" mode. The battery charges best when TeleMetrum
is turned off.
</para>
<para>
It's impossible to stop the TeleDongle when it's in "p" mode, I have
to unplug the USB cable? Make sure you have tried to "escape out" of
this mode. If this doesn't work the reboot procedure for the
TeleDongle *is* to simply unplug it. 'cu' however will retain it's
outgoing buffer IF your "escape out" ('~~') does not work.
At this point using either 'ao-view' (or possibly
'cutemon') instead of 'cu' will 'clear' the issue and allow renewed
communication.
</para>
<para>
The amber LED (on the TeleMetrum/altimeter) lights up when both
battery and USB are connected. Does this mean it's charging?
Yes, the yellow LED indicates the charging at the 'regular' rate.
If the led is out but the unit is still plugged into a USB port,
then the battery is being charged at a 'trickle' rate.
</para>
<para>
There are no "dit-dah-dah-dit" sound like the manual mentions?
That's the "pad" mode. Weak batteries might be the problem.
It is also possible that the unit is horizontal and the output
is instead a "dit-dit" meaning 'idle'.
</para>
<para>
It's unclear how to use 'ao-view' and other programs when 'cu'
is running. You cannot have more than one program connected to
the TeleDongle at one time without apparent data loss as the
incoming data will not make it to both programs intact.
Disconnect whatever programs aren't currently being used.
</para>
<para>
How do I save flight data?
Live telemetry is written to file(s) whenever 'ao-view' is connected
to the TeleDongle. The file area defaults to ~/altos
but is easily changed using the menus in 'ao-view'. The files that
are written end in '.telem'. The after-flight
data-dumped files will end in .eeprom and represent continuous data
unlike the rf-linked .telem files that are subject to the
turnarounds/data-packaging time slots in the half-duplex rf data path.
See the above instructions on what and how to save the eeprom stored
data after physically retrieving your TeleMetrum. Make sure to save
the on-board data after each flight, as the current firmware will
over-write any previous flight data during a new flight.
</para>
</section>
</chapter>
<chapter>
<title>Specifications</title>
<itemizedlist>
<listitem>
<para>
Recording altimeter for model rocketry.
</para>
</listitem>
<listitem>
<para>
Supports dual deployment (can fire 2 ejection charges).
</para>
</listitem>
<listitem>
<para>
70cm ham-band transceiver for telemetry downlink.
</para>
</listitem>
<listitem>
<para>
Barometric pressure sensor good to 45k feet MSL.
</para>
</listitem>
<listitem>
<para>
1-axis high-g accelerometer for motor characterization, capable of
+/- 50g using default part.
</para>
</listitem>
<listitem>
<para>
On-board, integrated GPS receiver with 5hz update rate capability.
</para>
</listitem>
<listitem>
<para>
On-board 1 megabyte non-volatile memory for flight data storage.
</para>
</listitem>
<listitem>
<para>
USB interface for battery charging, configuration, and data recovery.
</para>
</listitem>
<listitem>
<para>
Fully integrated support for LiPo rechargeable batteries.
</para>
</listitem>
<listitem>
<para>
Uses LiPo to fire e-matches, support for optional separate pyro
battery if needed.
</para>
</listitem>
<listitem>
<para>
2.75 x 1 inch board designed to fit inside 29mm airframe coupler tube.
</para>
</listitem>
</itemizedlist>
</chapter>
<chapter>
<title>Handling Precautions</title>
<para>
TeleMetrum is a sophisticated electronic device. When handled gently and
properly installed in an airframe, it will deliver impressive results.
However, like all electronic devices, there are some precautions you
must take.
</para>
<para>
The Lithium Polymer rechargeable batteries used with TeleMetrum have an
extraordinary power density. This is great because we can fly with
much less battery mass than if we used alkaline batteries or previous
generation rechargeable batteries... but if they are punctured
or their leads are allowed to short, they can and will release their
energy very rapidly!
Thus we recommend that you take some care when handling our batteries
and consider giving them some extra protection in your airframe. We
often wrap them in suitable scraps of closed-cell packing foam before
strapping them down, for example.
</para>
<para>
The TeleMetrum barometric sensor is sensitive to sunlight. In normal
mounting situations, it and all of the other surface mount components
are "down" towards whatever the underlying mounting surface is, so
this is not normally a problem. Please consider this, though, when
designing an installation, for example, in a 29mm airframe with a
see-through plastic payload bay.
</para>
<para>
The TeleMetrum barometric sensor sampling port must be able to
"breathe",
both by not being covered by foam or tape or other materials that might
directly block the hole on the top of the sensor, but also by having a
suitable static vent to outside air.
</para>
<para>
As with all other rocketry electronics, TeleMetrum must be protected
from exposure to corrosive motor exhaust and ejection charge gasses.
</para>
</chapter>
<chapter>
<title>Hardware Overview</title>
<para>
TeleMetrum is a 1 inch by 2.75 inch circuit board. It was designed to
fit inside coupler for 29mm airframe tubing, but using it in a tube that
small in diameter may require some creativity in mounting and wiring
to succeed! The default 1/4
wave UHF wire antenna attached to the center of the nose-cone end of
the board is about 7 inches long, and wiring for a power switch and
the e-matches for apogee and main ejection charges depart from the
fin can end of the board. Given all this, an ideal "simple" avionics
bay for TeleMetrum should have at least 10 inches of interior length.
</para>
<para>
A typical TeleMetrum installation using the on-board GPS antenna and
default wire UHF antenna involves attaching only a suitable
Lithium Polymer battery, a single pole switch for power on/off, and
two pairs of wires connecting e-matches for the apogee and main ejection
charges.
</para>
<para>
By default, we use the unregulated output of the LiPo battery directly
to fire ejection charges. This works marvelously with standard
low-current e-matches like the J-Tek from MJG Technologies, and with
Quest Q2G2 igniters. However, if you
want or need to use a separate pyro battery, you can do so by adding
a second 2mm connector to position B2 on the board and cutting the
thick pcb trace connecting the LiPo battery to the pyro circuit between
the two silk screen marks on the surface mount side of the board shown
here [insert photo]
</para>
<para>
We offer two choices of pyro and power switch connector, or you can
choose neither and solder wires directly to the board. All three choices
are reasonable depending on the constraints of your airframe. Our
favorite option when there is sufficient room above the board is to use
the Tyco pin header with polarization and locking. If you choose this
option, you crimp individual wires for the power switch and e-matches
into a mating connector, and installing and removing the TeleMetrum
board from an airframe is as easy as plugging or unplugging two
connectors. If the airframe will not support this much height or if
you want to be able to directly attach e-match leads to the board, we
offer a screw terminal block. This is very similar to what most other
altimeter vendors provide and so may be the most familiar option.
You'll need a very small straight blade screwdriver to connect
and disconnect the board in this case, such as you might find in a
jeweler's screwdriver set. Finally, you can forego both options and
solder wires directly to the board, which may be the best choice for
minimum diameter and/or minimum mass designs.
</para>
<para>
For most airframes, the integrated GPS antenna and wire UHF antenna are
a great combination. However, if you are installing in a carbon-fiber
electronics bay which is opaque to RF signals, you may need to use
off-board external antennas instead. In this case, you can order
TeleMetrum with an SMA connector for the UHF antenna connection, and
you can unplug the integrated GPS antenna and select an appropriate
off-board GPS antenna with cable terminating in a U.FL connector.
</para>
</chapter>
<chapter>
<title>System Operation</title>
<section>
<title>Firmware Modes </title>
<para>
The AltOS firmware build for TeleMetrum has two fundamental modes,
"idle" and "flight". Which of these modes the firmware operates in
is determined by the orientation of the rocket (well, actually the
board, of course...) at the time power is switched on. If the rocket
is "nose up", then TeleMetrum assumes it's on a rail or rod being
prepared for launch, so the firmware chooses flight mode. However,
if the rocket is more or less horizontal, the firmware instead enters
idle mode.
</para>
<para>
At power on, you will hear three beeps
("S" in Morse code for startup) and then a pause while
TeleMetrum completes initialization and self tests, and decides which
mode to enter next.
</para>
<para>
In flight or "pad" mode, TeleMetrum turns on the GPS system,
engages the flight
state machine, goes into transmit-only mode on the RF link sending
telemetry, and waits for launch to be detected. Flight mode is
indicated by an audible "di-dah-dah-dit" ("P" for pad) on the
beeper, followed by
beeps indicating the state of the pyrotechnic igniter continuity.
One beep indicates apogee continuity, two beeps indicate
main continuity, three beeps indicate both apogee and main continuity,
and one longer "brap" sound indicates no continuity. For a dual
deploy flight, make sure you're getting three beeps before launching!
For apogee-only or motor eject flights, do what makes sense.
</para>
<para>
In idle mode, you will hear an audible "di-dit" ("I" for idle), and
the normal flight state machine is disengaged, thus
no ejection charges will fire. TeleMetrum also listens on the RF
link when in idle mode for packet mode requests sent from TeleDongle.
Commands can be issued to a TeleMetrum in idle mode over either
USB or the RF link equivalently.
Idle mode is useful for configuring TeleMetrum, for extracting data
from the on-board storage chip after flight, and for ground testing
pyro charges.
</para>
<para>
One "neat trick" of particular value when TeleMetrum is used with very
large airframes, is that you can power the board up while the rocket
is horizontal, such that it comes up in idle mode. Then you can
raise the airframe to launch position, use a TeleDongle to open
a packet connection, and issue a 'reset' command which will cause
TeleMetrum to reboot, realize it's now nose-up, and thus choose
flight mode. This is much safer than standing on the top step of a
rickety step-ladder or hanging off the side of a launch tower with
a screw-driver trying to turn on your avionics before installing
igniters!
</para>
</section>
<section>
<title>GPS </title>
<para>
TeleMetrum includes a complete GPS receiver. See a later section for
a brief explanation of how GPS works that will help you understand
the information in the telemetry stream. The bottom line is that
the TeleMetrum GPS receiver needs to lock onto at least four
satellites to obtain a solid 3 dimensional position fix and know
what time it is!
</para>
<para>
TeleMetrum provides backup power to the GPS chip any time a LiPo
battery is connected. This allows the receiver to "warm start" on
the launch rail much faster than if every power-on were a "cold start"
for the GPS receiver. In typical operations, powering up TeleMetrum
on the flight line in idle mode while performing final airframe
preparation will be sufficient to allow the GPS receiver to cold
start and acquire lock. Then the board can be powered down during
RSO review and installation on a launch rod or rail. When the board
is turned back on, the GPS system should lock very quickly, typically
long before igniter installation and return to the flight line are
complete.
</para>
</section>
<section>
<title>Ground Testing </title>
<para>
An important aspect of preparing a rocket using electronic deployment
for flight is ground testing the recovery system. Thanks
to the bi-directional RF link central to the Altus Metrum system,
this can be accomplished in a TeleMetrum-equipped rocket without as
much work as you may be accustomed to with other systems. It can
even be fun!
</para>
<para>
Just prep the rocket for flight, then power up TeleMetrum while the
airframe is horizontal. This will cause the firmware to go into
"idle" mode, in which the normal flight state machine is disabled and
charges will not fire without manual command. Then, establish an
RF packet connection from a TeleDongle-equipped computer using the
P command from a safe distance. You can now command TeleMetrum to
fire the apogee or main charges to complete your testing.
</para>
<para>
In order to reduce the chance of accidental firing of pyrotechnic
charges, the command to fire a charge is intentionally somewhat
difficult to type, and the built-in help is slightly cryptic to
prevent accidental echoing of characters from the help text back at
the board from firing a charge. The command to fire the apogee
drogue charge is 'i DoIt drogue' and the command to fire the main
charge is 'i DoIt main'.
</para>
</section>
<section>
<title>Radio Link </title>
<para>
The chip our boards are based on incorporates an RF transceiver, but
it's not a full duplex system... each end can only be transmitting or
receiving at any given moment. So we had to decide how to manage the
link.
</para>
<para>
By design, TeleMetrum firmware listens for an RF connection when
it's in "idle mode" (turned on while the rocket is horizontal), which
allows us to use the RF link to configure the rocket, do things like
ejection tests, and extract data after a flight without having to
crack open the airframe. However, when the board is in "flight
mode" (turned on when the rocket is vertical) the TeleMetrum only
transmits and doesn't listen at all. That's because we want to put
ultimate priority on event detection and getting telemetry out of
the rocket and out over
the RF link in case the rocket crashes and we aren't able to extract
data later...
</para>
<para>
We don't use a 'normal packet radio' mode because they're just too
inefficient. The GFSK modulation we use is just FSK with the
baseband pulses passed through a
Gaussian filter before they go into the modulator to limit the
transmitted bandwidth. When combined with the hardware forward error
correction support in the cc1111 chip, this allows us to have a very
robust 38.4 kilobit data link with only 10 milliwatts of transmit power,
a whip antenna in the rocket, and a hand-held Yagi on the ground. We've
had flights to above 21k feet AGL with good reception, and calculations
suggest we should be good to well over 40k feet AGL with a 5-element yagi on
the ground. We hope to fly boards to higher altitudes soon, and would
of course appreciate customer feedback on performance in higher
altitude flights!
</para>
</section>
<section>
<title>Configurable Parameters</title>
<para>
Configuring a TeleMetrum board for flight is very simple. Because we
have both acceleration and pressure sensors, there is no need to set
a "mach delay", for example. The few configurable parameters can all
be set using a simple terminal program over the USB port or RF link
via TeleDongle.
</para>
<section>
<title>Radio Channel</title>
<para>
Our firmware supports 10 channels. The default channel 0 corresponds
to a center frequency of 434.550 Mhz, and channels are spaced every
100 khz. Thus, channel 1 is 434.650 Mhz, and channel 9 is 435.550 Mhz.
At any given launch, we highly recommend coordinating who will use
each channel and when to avoid interference. And of course, both
TeleMetrum and TeleDongle must be configured to the same channel to
successfully communicate with each other.
</para>
<para>
To set the radio channel, use the 'c r' command, like 'c r 3' to set
channel 3.
As with all 'c' sub-commands, follow this with a 'c w' to write the
change to the parameter block in the on-board DataFlash chip on
your TeleMetrum board if you want the change to stay in place across reboots.
</para>
</section>
<section>
<title>Apogee Delay</title>
<para>
Apogee delay is the number of seconds after TeleMetrum detects flight
apogee that the drogue charge should be fired. In most cases, this
should be left at the default of 0. However, if you are flying
redundant electronics such as for an L3 certification, you may wish
to set one of your altimeters to a positive delay so that both
primary and backup pyrotechnic charges do not fire simultaneously.
</para>
<para>
To set the apogee delay, use the [FIXME] command.
As with all 'c' sub-commands, follow this with a 'c w' to write the
change to the parameter block in the on-board DataFlash chip.
</para>
<para>
Please note that the TeleMetrum apogee detection algorithm always
fires a fraction of a second *after* apogee. If you are also flying
an altimeter like the PerfectFlite MAWD, which only supports selecting
0 or 1 seconds of apogee delay, you may wish to set the MAWD to 0
seconds delay and set the TeleMetrum to fire your backup 2 or 3
seconds later to avoid any chance of both charges firing
simultaneously. We've flown several airframes this way quite happily,
including Keith's successful L3 cert.
</para>
</section>
<section>
<title>Main Deployment Altitude</title>
<para>
By default, TeleMetrum will fire the main deployment charge at an
elevation of 250 meters (about 820 feet) above ground. We think this
is a good elevation for most airframes, but feel free to change this
to suit. In particular, if you are flying two altimeters, you may
wish to set the
deployment elevation for the backup altimeter to be something lower
than the primary so that both pyrotechnic charges don't fire
simultaneously.
</para>
<para>
To set the main deployment altitude, use the [FIXME] command.
As with all 'c' sub-commands, follow this with a 'c w' to write the
change to the parameter block in the on-board DataFlash chip.
</para>
</section>
</section>
<section>
<title>Calibration</title>
<para>
There are only two calibrations required for a TeleMetrum board, and
only one for TeleDongle.
</para>
<section>
<title>Radio Frequency</title>
<para>
The radio frequency is synthesized from a clock based on the 48 Mhz
crystal on the board. The actual frequency of this oscillator must be
measured to generate a calibration constant. While our GFSK modulation
bandwidth is wide enough to allow boards to communicate even when
their oscillators are not on exactly the same frequency, performance
is best when they are closely matched.
Radio frequency calibration requires a calibrated frequency counter.
Fortunately, once set, the variation in frequency due to aging and
temperature changes is small enough that re-calibration by customers
should generally not be required.
</para>
<para>
To calibrate the radio frequency, connect the UHF antenna port to a
frequency counter, set the board to channel 0, and use the 'C'
command to generate a CW carrier. Wait for the transmitter temperature
to stabilize and the frequency to settle down.
Then, divide 434.550 Mhz by the
measured frequency and multiply by the current radio cal value show
in the 'c s' command. For an unprogrammed board, the default value
is 1186611. Take the resulting integer and program it using the 'c f'
command. Testing with the 'C' command again should show a carrier
within a few tens of Hertz of the intended frequency.
As with all 'c' sub-commands, follow this with a 'c w' to write the
change to the parameter block in the on-board DataFlash chip.
</para>
</section>
<section>
<title>Accelerometer</title>
<para>
The accelerometer we use has its own 5 volt power supply and
the output must be passed through a resistive voltage divider to match
the input of our 3.3 volt ADC. This means that unlike the barometric
sensor, the output of the acceleration sensor is not ratiometric to
the ADC converter, and calibration is required. We also support the
use of any of several accelerometers from a Freescale family that
includes at least +/- 40g, 50g, 100g, and 200g parts. Using gravity,
a simple 2-point calibration yields acceptable results capturing both
the different sensitivities and ranges of the different accelerometer
parts and any variation in power supply voltages or resistor values
in the divider network.
</para>
<para>
To calibrate the acceleration sensor, use the 'c a 0' command. You
will be prompted to orient the board vertically with the UHF antenna
up and press a key, then to orient the board vertically with the
UHF antenna down and press a key.
As with all 'c' sub-commands, follow this with a 'c w' to write the
change to the parameter block in the on-board DataFlash chip.
</para>
<para>
The +1g and -1g calibration points are included in each telemetry
frame and are part of the header extracted by ao-dumplog after flight.
Note that we always store and return raw ADC samples for each
sensor... nothing is permanently "lost" or "damaged" if the
calibration is poor.
</para>
<para>
In the unlikely event an accel cal that goes badly, it is possible
that TeleMetrum may always come up in 'pad mode' and as such not be
listening to either the USB or radio interfaces. If that happens,
there is a special hook in the firmware to force the board back
in to 'idle mode' so you can re-do the cal. To use this hook, you
just need to ground the SPI clock pin at power-on. This pin is
available as pin 2 on the 8-pin companion connector, and pin 1 is
ground. So either carefully install a fine-gauge wire jumper
between the two pins closest to the index hole end of the 8-pin
connector, or plug in the programming cable to the 8-pin connector
and use a small screwdriver or similar to short the two pins closest
to the index post on the 4-pin end of the programming cable, and
power up the board. It should come up in 'idle mode' (two beeps).
</para>
</section>
</section>
<section>
<title>Updating Device Firmware</title>
<para>
The big conceptual thing to realize is that you have to use a
TeleDongle as a programmer to update a TeleMetrum, and vice versa.
Due to limited memory resources in the cc1111, we don't support
programming either unit directly over USB.
</para>
<para>
You may wish to begin by ensuring you have current firmware images.
These are distributed as part of the AltOS software bundle that
also includes the AltosUI ground station program. Newer ground
station versions typically work fine with older firmware versions,
so you don't need to update your devices just to try out new
software features. You can always download the most recent
version from http://www.altusmetrum.org/AltOS/.
</para>
<para>
We recommend updating TeleMetrum first, before updating TeleDongle.
</para>
<section>
<title>Updating TeleMetrum Firmware</title>
<orderedlist inheritnum='inherit' numeration='arabic'>
<listitem>
Find the 'programming cable' that you got as part of the starter
kit, that has a red 8-pin MicroMaTch connector on one end and a
red 4-pin MicroMaTch connector on the other end.
</listitem>
<listitem>
Take the 2 screws out of the TeleDongle case to get access
to the circuit board.
</listitem>
<listitem>
Plug the 8-pin end of the programming cable to the
matching connector on the TeleDongle, and the 4-pin end to the
matching connector on the TeleMetrum.
Note that each MicroMaTch connector has an alignment pin that
goes through a hole in the PC board when you have the cable
oriented correctly.
</listitem>
<listitem>
Attach a battery to the TeleMetrum board.
</listitem>
<listitem>
Plug the TeleDongle into your computer's USB port, and power
up the TeleMetrum.
</listitem>
<listitem>
Run AltosUI, and select 'Flash Image' from the File menu.
</listitem>
<listitem>
Pick the TeleDongle device from the list, identifying it as the
programming device.
</listitem>
<listitem>
Select the image you want put on the TeleMetrum, which should have a
name in the form telemetrum-v1.0-0.7.1.ihx. It should be visible
in the default directory, if not you may have to poke around
your system to find it.
</listitem>
<listitem>
Make sure the configuration parameters are reasonable
looking. If the serial number and/or RF configuration
values aren't right, you'll need to change them.
</listitem>
<listitem>
Hit the 'OK' button and the software should proceed to flash
the TeleMetrum with new firmware, showing a progress bar.
</listitem>
<listitem>
Confirm that the TeleMetrum board seems to have updated ok, which you
can do by plugging in to it over USB and using a terminal program
to connect to the board and issue the 'v' command to check
the version, etc.
</listitem>
<listitem>
If something goes wrong, give it another try.
</listitem>
</orderedlist>
</section>
<section>
<title>Updating TeleDongle Firmware</title>
<para>
Updating TeleDongle's firmware is just like updating TeleMetrum
firmware, but you switch which board is the programmer and which
is the programming target.
</para>
<orderedlist inheritnum='inherit' numeration='arabic'>
<listitem>
Find the 'programming cable' that you got as part of the starter
kit, that has a red 8-pin MicroMaTch connector on one end and a
red 4-pin MicroMaTch connector on the other end.
</listitem>
<listitem>
Find the USB cable that you got as part of the starter kit, and
plug the "mini" end in to the mating connector on TeleMetrum.
</listitem>
<listitem>
Take the 2 screws out of the TeleDongle case to get access
to the circuit board.
</listitem>
<listitem>
Plug the 8-pin end of the programming cable to the (latching)
matching connector on the TeleMetrum, and the 4-pin end to the
matching connector on the TeleDongle.
Note that each MicroMaTch connector has an alignment pin that
goes through a hole in the PC board when you have the cable
oriented correctly.
</listitem>
<listitem>
Attach a battery to the TeleMetrum board.
</listitem>
<listitem>
Plug both TeleMetrum and TeleDongle into your computer's USB
ports, and power up the TeleMetrum.
</listitem>
<listitem>
Run AltosUI, and select 'Flash Image' from the File menu.
</listitem>
<listitem>
Pick the TeleMetrum device from the list, identifying it as the
programming device.
</listitem>
<listitem>
Select the image you want put on the TeleDongle, which should have a
name in the form teledongle-v0.2-0.7.1.ihx. It should be visible
in the default directory, if not you may have to poke around
your system to find it.
</listitem>
<listitem>
Make sure the configuration parameters are reasonable
looking. If the serial number and/or RF configuration
values aren't right, you'll need to change them. The TeleDongle
serial number is on the "bottom" of the circuit board, and can
usually be read through the translucent blue plastic case without
needing to remove the board from the case.
</listitem>
<listitem>
Hit the 'OK' button and the software should proceed to flash
the TeleDongle with new firmware, showing a progress bar.
</listitem>
<listitem>
Confirm that the TeleDongle board seems to have updated ok, which you
can do by plugging in to it over USB and using a terminal program
to connect to the board and issue the 'v' command to check
the version, etc. Once you're happy, remove the programming cable
and put the cover back on the TeleDongle.
</listitem>
<listitem>
If something goes wrong, give it another try.
</listitem>
</orderedlist>
<para>
Be careful removing the programming cable from the locking 8-pin
connector on TeleMetrum. You'll need a fingernail or perhaps a thin
screwdriver or knife blade to gently pry the locking ears out
slightly to extract the connector. We used a locking connector on
TeleMetrum to help ensure that the cabling to companion boards
used in a rocket don't ever come loose accidentally in flight.
</para>
</section>
</section>
</chapter>
<chapter>
<title>AltosUI</title>
<para>
The AltosUI program provides a graphical user interface for
interacting with the Altus Metrum product family, including
TeleMetrum and TeleDongle. AltosUI can monitor telemetry data,
configure TeleMetrum and TeleDongle devices and many other
tasks. The primary interface window provides a selection of
buttons, one for each major activity in the system. This manual
is split into chapters, each of which documents one of the tasks
provided from the top-level toolbar.
</para>
<section>
<title>Packet Command Mode</title>
<subtitle>Controlling TeleMetrum Over The Radio Link</subtitle>
<para>
One of the unique features of the Altos Metrum environment is
the ability to create a two way command link between TeleDongle
and TeleMetrum using the digital radio transceivers built into
each device. This allows you to interact with TeleMetrum from
afar, as if it were directly connected to the computer.
</para>
<para>
Any operation which can be performed with TeleMetrum
can either be done with TeleMetrum directly connected to
the computer via the USB cable, or through the packet
link. Simply select the appropriate TeleDongle device when
the list of devices is presented and AltosUI will use packet
command mode.
</para>
<itemizedlist>
<listitem>
<para>
Save Flight Data—Recover flight data from the rocket without
opening it up.
</para>
</listitem>
<listitem>
<para>
Configure TeleMetrum—Reset apogee delays or main deploy
heights to respond to changing launch conditions. You can
also 'reboot' the TeleMetrum device. Use this to remotely
enable the flight computer by turning TeleMetrum on while
horizontal, then once the airframe is oriented for launch,
you can reboot TeleMetrum and have it restart in pad mode
without having to climb the scary ladder.
</para>
</listitem>
<listitem>
<para>
Fire Igniters—Test your deployment charges without snaking
wires out through holes in the airframe. Simply assembly the
rocket as if for flight with the apogee and main charges
loaded, then remotely command TeleMetrum to fire the
igniters.
</para>
</listitem>
</itemizedlist>
<para>
Packet command mode uses the same RF channels as telemetry
mode. Configure the desired TeleDongle channel using the
flight monitor window channel selector and then close that
window before performing the desired operation.
</para>
<para>
TeleMetrum only enables packet command mode in 'idle' mode, so
make sure you have TeleMetrum lying horizontally when you turn
it on. Otherwise, TeleMetrum will start in 'pad' mode ready for
flight and will not be listening for command packets from TeleDongle.
</para>
<para>
When packet command mode is enabled, you can monitor the link
by watching the lights on the TeleDongle and TeleMetrum
devices. The red LED will flash each time TeleDongle or
TeleMetrum transmit a packet while the green LED will light up
on TeleDongle while it is waiting to receive a packet from
TeleMetrum.
</para>
</section>
<section>
<title>Monitor Flight</title>
<subtitle>Receive, Record and Display Telemetry Data</subtitle>
<para>
Selecting this item brings up a dialog box listing all of the
connected TeleDongle devices. When you choose one of these,
AltosUI will create a window to display telemetry data as
received by the selected TeleDongle device.
</para>
<para>
All telemetry data received are automatically recorded in
suitable log files. The name of the files includes the current
date and rocket serial and flight numbers.
</para>
<para>
The radio channel being monitored by the TeleDongle device is
displayed at the top of the window. You can configure the
channel by clicking on the channel box and selecting the desired
channel. AltosUI remembers the last channel selected for each
TeleDongle and selects that automatically the next time you use
that device.
</para>
<para>
Below the TeleDongle channel selector, the window contains a few
significant pieces of information about the TeleMetrum providing
the telemetry data stream:
</para>
<itemizedlist>
<listitem>
<para>The TeleMetrum callsign</para>
</listitem>
<listitem>
<para>The TeleMetrum serial number</para>
</listitem>
<listitem>
<para>The flight number. Each TeleMetrum remembers how many
times it has flown.
</para>
</listitem>
<listitem>
<para>
The rocket flight state. Each flight passes through several
states including Pad, Boost, Fast, Coast, Drogue, Main and
Landed.
</para>
</listitem>
<listitem>
<para>
The Received Signal Strength Indicator value. This lets
you know how strong a signal TeleDongle is receiving. The
radio inside TeleDongle operates down to about -99dBm;
weaker signals may not be receiveable. The packet link uses
error correction and detection techniques which prevent
incorrect data from being reported.
</para>
</listitem>
</itemizedlist>
<para>
Finally, the largest portion of the window contains a set of
tabs, each of which contain some information about the rocket.
They're arranged in 'flight order' so that as the flight
progresses, the selected tab automatically switches to display
data relevant to the current state of the flight. You can select
other tabs at any time. The final 'table' tab contains all of
the telemetry data in one place.
</para>
<section>
<title>Launch Pad</title>
<para>
The 'Launch Pad' tab shows information used to decide when the
rocket is ready for flight. The first elements include red/green
indicators, if any of these is red, you'll want to evaluate
whether the rocket is ready to launch:
<itemizedlist>
<listitem>
<para>
Battery Voltage. This indicates whether the LiPo battery
powering the TeleMetrum has sufficient charge to last for
the duration of the flight. A value of more than
3.7V is required for a 'GO' status.
</para>
</listitem>
<listitem>
<para>
Apogee Igniter Voltage. This indicates whether the apogee
igniter has continuity. If the igniter has a low
resistance, then the voltage measured here will be close
to the LiPo battery voltage. A value greater than 3.2V is
required for a 'GO' status.
</para>
</listitem>
<listitem>
<para>
Main Igniter Voltage. This indicates whether the main
igniter has continuity. If the igniter has a low
resistance, then the voltage measured here will be close
to the LiPo battery voltage. A value greater than 3.2V is
required for a 'GO' status.
</para>
</listitem>
<listitem>
<para>
GPS Locked. This indicates whether the GPS receiver is
currently able to compute position information. GPS requires
at least 4 satellites to compute an accurate position.
</para>
</listitem>
<listitem>
<para>
GPS Ready. This indicates whether GPS has reported at least
10 consecutive positions without losing lock. This ensures
that the GPS receiver has reliable reception from the
satellites.
</para>
</listitem>
</itemizedlist>
<para>
The LaunchPad tab also shows the computed launch pad position
and altitude, averaging many reported positions to improve the
accuracy of the fix.
</para>
</para>
</section>
<section>
<title>Ascent</title>
<para>
This tab is shown during Boost, Fast and Coast
phases. The information displayed here helps monitor the
rocket as it heads towards apogee.
</para>
<para>
The height, speed and acceleration are shown along with the
maxium values for each of them. This allows you to quickly
answer the most commonly asked questions you'll hear during
flight.
</para>
<para>
The current latitude and longitude reported by the GPS are
also shown. Note that under high acceleration, these values
may not get updated as the GPS receiver loses position
fix. Once the rocket starts coasting, the receiver should
start reporting position again.
</para>
<para>
Finally, the current igniter voltages are reported as in the
Launch Pad tab. This can help diagnose deployment failures
caused by wiring which comes loose under high acceleration.
</para>
</section>
<section>
<title>Descent</title>
<para>
Once the rocket has reached apogee and (we hope) activated the
apogee charge, attention switches to tracking the rocket on
the way back to the ground, and for dual-deploy flights,
waiting for the main charge to fire.
</para>
<para>
To monitor whether the apogee charge operated correctly, the
current descent rate is reported along with the current
height. Good descent rates generally range from 15-30m/s.
</para>
<para>
To help locate the rocket in the sky, use the elevation and
bearing information to figure out where to look. Elevation is
in degrees above the horizon. Bearing is reported in degrees
relative to true north. Range can help figure out how big the
rocket will appear. Note that all of these values are relative
to the pad location. If the elevation is near 90°, the rocket
is over the pad, not over you.
</para>
<para>
Finally, the igniter voltages are reported in this tab as
well, both to monitor the main charge as well as to see what
the status of the apogee charge is.
</para>
</section>
<section>
<title>Landed</title>
<para>
Once the rocket is on the ground, attention switches to
recovery. While the radio signal is generally lost once the
rocket is on the ground, the last reported GPS position is
generally within a short distance of the actual landing location.
</para>
<para>
The last reported GPS position is reported both by
latitude and longitude as well as a bearing and distance from
the launch pad. The distance should give you a good idea of
whether you'll want to walk or hitch a ride. Take the reported
latitude and longitude and enter them into your handheld GPS
unit and have that compute a track to the landing location.
</para>
<para>
Finally, the maximum height, speed and acceleration reported
during the flight are displayed for your admiring observers.
</para>
</section>
<section>
<title>Site Map</title>
<para>
When the rocket gets a GPS fix, the Site Map tab will map
the rocket's position to make it easier for you to locate the
rocket, both while it is in the air, and when it has landed. The
rocket's state is indicated by colour: white for pad, red for
boost, pink for fast, yellow for coast, light blue for drogue,
dark blue for main, and black for landed.
</para>
<para>
The map's scale is approximately 3m (10ft) per pixel. The map
can be dragged using the left mouse button. The map will attempt
to keep the rocket roughly centred while data is being received.
</para>
<para>
Images are fetched automatically via the Google Maps Static API,
and are cached for reuse. If map images cannot be downloaded,
the rocket's path will be traced on a dark grey background
instead.
</para>
</section>
</section>
<section>
<title>Save Flight Data</title>
<para>
TeleMetrum records flight data to its internal flash memory.
This data is recorded at a much higher rate than the telemetry
system can handle, and is not subject to radio drop-outs. As
such, it provides a more complete and precise record of the
flight. The 'Save Flight Data' button allows you to read the
flash memory and write it to disk.
</para>
<para>
Clicking on the 'Save Flight Data' button brings up a list of
connected TeleMetrum and TeleDongle devices. If you select a
TeleMetrum device, the flight data will be downloaded from that
device directly. If you select a TeleDongle device, flight data
will be downloaded from a TeleMetrum device connected via the
packet command link to the specified TeleDongle. See the chapter
on Packet Command Mode for more information about this.
</para>
<para>
The filename for the data is computed automatically from the recorded
flight date, TeleMetrum serial number and flight number
information.
</para>
</section>
<section>
<title>Replay Flight</title>
<para>
Select this button and you are prompted to select a flight
record file, either a .telem file recording telemetry data or a
.eeprom file containing flight data saved from the TeleMetrum
flash memory.
</para>
<para>
Once a flight record is selected, the flight monitor interface
is displayed and the flight is re-enacted in real time. Check
the Monitor Flight chapter above to learn how this window operates.
</para>
</section>
<section>
<title>Graph Data</title>
<para>
Select this button and you are prompted to select a flight
record file, either a .telem file recording telemetry data or a
.eeprom file containing flight data saved from the TeleMetrum
flash memory.
</para>
<para>
Once a flight record is selected, the acceleration (blue),
velocity (green) and altitude (red) of the flight are plotted and
displayed, measured in metric units.
</para>
<para>
The graph can be zoomed into a particular area by clicking and
dragging down and to the right. Once zoomed, the graph can be
reset by clicking and dragging up and to the left. Holding down
control and clicking and dragging allows the graph to be panned.
The right mouse button causes a popup menu to be displayed, giving
you the option save or print the plot.
</para>
<para>
Note that telemetry files will generally produce poor graphs
due to the lower sampling rate and missed telemetry packets,
and will also often have significant amounts of data received
while the rocket was waiting on the pad. Use saved flight data
for graphing where possible.
</para>
</section>
<section>
<title>Export Data</title>
<para>
This tool takes the raw data files and makes them available for
external analysis. When you select this button, you are prompted to select a flight
data file (either .eeprom or .telem will do, remember that
.eeprom files contain higher resolution and more continuous
data). Next, a second dialog appears which is used to select
where to write the resulting file. It has a selector to choose
between CSV and KML file formats.
</para>
<section>
<title>Comma Separated Value Format</title>
<para>
This is a text file containing the data in a form suitable for
import into a spreadsheet or other external data analysis
tool. The first few lines of the file contain the version and
configuration information from the TeleMetrum device, then
there is a single header line which labels all of the
fields. All of these lines start with a '#' character which
most tools can be configured to skip over.
</para>
<para>
The remaining lines of the file contain the data, with each
field separated by a comma and at least one space. All of
the sensor values are converted to standard units, with the
barometric data reported in both pressure, altitude and
height above pad units.
</para>
</section>
<section>
<title>Keyhole Markup Language (for Google Earth)</title>
<para>
This is the format used by
Googleearth to provide an overlay within that
application. With this, you can use Googleearth to see the
whole flight path in 3D.
</para>
</section>
</section>
<section>
<title>Configure TeleMetrum</title>
<para>
Select this button and then select either a TeleMetrum or
TeleDongle Device from the list provided. Selecting a TeleDongle
device will use Packet Comamnd Mode to configure remote
TeleMetrum device. Learn how to use this in the Packet Command
Mode chapter.
</para>
<para>
The first few lines of the dialog provide information about the
connected TeleMetrum device, including the product name,
software version and hardware serial number. Below that are the
individual configuration entries.
</para>
<para>
At the bottom of the dialog, there are four buttons:
</para>
<itemizedlist>
<listitem>
<para>
Save. This writes any changes to the TeleMetrum
configuration parameter block in flash memory. If you don't
press this button, any changes you make will be lost.
</para>
</listitem>
<listitem>
<para>
Reset. This resets the dialog to the most recently saved values,
erasing any changes you have made.
</para>
</listitem>
<listitem>
<para>
Reboot. This reboots the TeleMetrum device. Use this to
switch from idle to pad mode by rebooting once the rocket is
oriented for flight.
</para>
</listitem>
<listitem>
<para>
Close. This closes the dialog. Any unsaved changes will be
lost.
</para>
</listitem>
</itemizedlist>
<para>
The rest of the dialog contains the parameters to be configured.
</para>
<section>
<title>Main Deploy Altitude</title>
<para>
This sets the altitude (above the recorded pad altitude) at
which the 'main' igniter will fire. The drop-down menu shows
some common values, but you can edit the text directly and
choose whatever you like. If the apogee charge fires below
this altitude, then the main charge will fire two seconds
after the apogee charge fires.
</para>
</section>
<section>
<title>Apogee Delay</title>
<para>
When flying redundant electronics, it's often important to
ensure that multiple apogee charges don't fire at precisely
the same time as that can overpressurize the apogee deployment
bay and cause a structural failure of the airframe. The Apogee
Delay parameter tells the flight computer to fire the apogee
charge a certain number of seconds after apogee has been
detected.
</para>
</section>
<section>
<title>Radio Channel</title>
<para>
This configures which of the 10 radio channels to use for both
telemetry and packet command mode. Note that if you set this
value via packet command mode, you will have to reconfigure
the TeleDongle channel before you will be able to use packet
command mode again.
</para>
</section>
<section>
<title>Radio Calibration</title>
<para>
The radios in every Altus Metrum device are calibrated at the
factory to ensure that they transmit and receive on the
specified frequency for each channel. You can adjust that
calibration by changing this value. To change the TeleDongle's
calibration, you must reprogram the unit completely.
</para>
</section>
<section>
<title>Callsign</title>
<para>
This sets the callsign included in each telemetry packet. Set this
as needed to conform to your local radio regulations.
</para>
</section>
</section>
<section>
<title>Configure AltosUI</title>
<para>
This button presents a dialog so that you can configure the AltosUI global settings.
</para>
<section>
<title>Voice Settings</title>
<para>
AltosUI provides voice annoucements during flight so that you
can keep your eyes on the sky and still get information about
the current flight status. However, sometimes you don't want
to hear them.
</para>
<itemizedlist>
<listitem>
<para>Enable—turns all voice announcements on and off</para>
</listitem>
<listitem>
<para>
Test Voice—Plays a short message allowing you to verify
that the audio systme is working and the volume settings
are reasonable
</para>
</listitem>
</itemizedlist>
</section>
<section>
<title>Log Directory</title>
<para>
AltosUI logs all telemetry data and saves all TeleMetrum flash
data to this directory. This directory is also used as the
staring point when selecting data files for display or export.
</para>
<para>
Click on the directory name to bring up a directory choosing
dialog, select a new directory and click 'Select Directory' to
change where AltosUI reads and writes data files.
</para>
</section>
<section>
<title>Callsign</title>
<para>
This value is used in command packet mode and is transmitted
in each packet sent from TeleDongle and received from
TeleMetrum. It is not used in telemetry mode as that transmits
packets only from TeleMetrum to TeleDongle. Configure this
with the AltosUI operators callsign as needed to comply with
your local radio regulations.
</para>
</section>
</section>
<section>
<title>Flash Image</title>
<para>
This reprograms any Altus Metrum device by using a TeleMetrum or
TeleDongle as a programming dongle. Please read the directions
for connecting the programming cable in the main TeleMetrum
manual before reading these instructions.
</para>
<para>
Once you have the programmer and target devices connected,
push the 'Flash Image' button. That will present a dialog box
listing all of the connected devices. Carefully select the
programmer device, not the device to be programmed.
</para>
<para>
Next, select the image to flash to the device. These are named
with the product name and firmware version. The file selector
will start in the directory containing the firmware included
with the AltosUI package. Navigate to the directory containing
the desired firmware if it isn't there.
</para>
<para>
Next, a small dialog containing the device serial number and
RF calibration values should appear. If these values are
incorrect (possibly due to a corrupted image in the device),
enter the correct values here.
</para>
<para>
Finally, a dialog containing a progress bar will follow the
programming process.
</para>
<para>
When programming is complete, the target device will
reboot. Note that if the target device is connected via USB, you
will have to unplug it and then plug it back in for the USB
connection to reset so that you can communicate with the device
again.
</para>
</section>
<section>
<title>Fire Igniter</title>
<para>
</para>
</section>
</chapter>
<chapter>
<title>Using Altus Metrum Products</title>
<section>
<title>Being Legal</title>
<para>
First off, in the US, you need an [amateur radio license](../Radio) or
other authorization to legally operate the radio transmitters that are part
of our products.
</para>
<section>
<title>In the Rocket</title>
<para>
In the rocket itself, you just need a [TeleMetrum](../TeleMetrum) board and
a LiPo rechargeable battery. An 860mAh battery weighs less than a 9V
alkaline battery, and will run a [TeleMetrum](../TeleMetrum) for hours.
</para>
<para>
By default, we ship TeleMetrum with a simple wire antenna. If your
electronics bay or the airframe it resides within is made of carbon fiber,
which is opaque to RF signals, you may choose to have an SMA connector
installed so that you can run a coaxial cable to an antenna mounted
elsewhere in the rocket.
</para>
</section>
<section>
<title>On the Ground</title>
<para>
To receive the data stream from the rocket, you need an antenna and short
feedline connected to one of our [TeleDongle](../TeleDongle) units. The
TeleDongle in turn plugs directly into the USB port on a notebook
computer. Because TeleDongle looks like a simple serial port, your computer
does not require special device drivers... just plug it in.
</para>
<para>
Right now, all of our application software is written for Linux. However,
because we understand that many people run Windows or MacOS, we are working
on a new ground station program written in Java that should work on all
operating systems.
</para>
<para>
After the flight, you can use the RF link to extract the more detailed data
logged in the rocket, or you can use a mini USB cable to plug into the
TeleMetrum board directly. Pulling out the data without having to open up
the rocket is pretty cool! A USB cable is also how you charge the LiPo
battery, so you'll want one of those anyway... the same cable used by lots
of digital cameras and other modern electronic stuff will work fine.
</para>
<para>
If your rocket lands out of sight, you may enjoy having a hand-held GPS
receiver, so that you can put in a waypoint for the last reported rocket
position before touch-down. This makes looking for your rocket a lot like
Geo-Cacheing... just go to the waypoint and look around starting from there.
</para>
<para>
You may also enjoy having a ham radio "HT" that covers the 70cm band... you
can use that with your antenna to direction-find the rocket on the ground
the same way you can use a Walston or Beeline tracker. This can be handy
if the rocket is hiding in sage brush or a tree, or if the last GPS position
doesn't get you close enough because the rocket dropped into a canyon, or
the wind is blowing it across a dry lake bed, or something like that... Keith
and Bdale both currently own and use the Yaesu VX-7R at launches.
</para>
<para>
So, to recap, on the ground the hardware you'll need includes:
<orderedlist inheritnum='inherit' numeration='arabic'>
<listitem>
an antenna and feedline
</listitem>
<listitem>
a TeleDongle
</listitem>
<listitem>
a notebook computer
</listitem>
<listitem>
optionally, a handheld GPS receiver
</listitem>
<listitem>
optionally, an HT or receiver covering 435 Mhz
</listitem>
</orderedlist>
</para>
<para>
The best hand-held commercial directional antennas we've found for radio
direction finding rockets are from
<ulink url="http://www.arrowantennas.com/" >
Arrow Antennas.
</ulink>
The 440-3 and 440-5 are both good choices for finding a
TeleMetrum-equipped rocket when used with a suitable 70cm HT.
</para>
</section>
<section>
<title>Data Analysis</title>
<para>
Our software makes it easy to log the data from each flight, both the
telemetry received over the RF link during the flight itself, and the more
complete data log recorded in the DataFlash memory on the TeleMetrum
board. Once this data is on your computer, our postflight tools make it
easy to quickly get to the numbers everyone wants, like apogee altitude,
max acceleration, and max velocity. You can also generate and view a
standard set of plots showing the altitude, acceleration, and
velocity of the rocket during flight. And you can even export a data file
useable with Google Maps and Google Earth for visualizing the flight path
in two or three dimensions!
</para>
<para>
Our ultimate goal is to emit a set of files for each flight that can be
published as a web page per flight, or just viewed on your local disk with
a web browser.
</para>
</section>
<section>
<title>Future Plans</title>
<para>
In the future, we intend to offer "companion boards" for the rocket that will
plug in to TeleMetrum to collect additional data, provide more pyro channels,
and so forth. A reference design for a companion board will be documented
soon, and will be compatible with open source Arduino programming tools.
</para>
<para>
We are also working on the design of a hand-held ground terminal that will
allow monitoring the rocket's status, collecting data during flight, and
logging data after flight without the need for a notebook computer on the
flight line. Particularly since it is so difficult to read most notebook
screens in direct sunlight, we think this will be a great thing to have.
</para>
<para>
Because all of our work is open, both the hardware designs and the software,
if you have some great idea for an addition to the current Altus Metrum family,
feel free to dive in and help! Or let us know what you'd like to see that
we aren't already working on, and maybe we'll get excited about it too...
</para>
</section>
</section>
</chapter>
</book>
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