+ <title>Using a Separate Pyro Battery with TeleMini v2.0</title>
+ <para>
+ As described above, using an external pyro battery involves
+ connecting the negative battery terminal to the flight
+ computer ground, connecting the positive battery terminal to
+ one of the igniter leads and connecting the other igniter
+ lead to the per-channel pyro circuit connection.
+ </para>
+ <para>
+ To connect the negative pyro battery terminal to TeleMini
+ ground, connect it to the negative external battery
+ connection, top terminal 4.
+ </para>
+ <para>
+ Connecting the positive battery terminal to the pyro
+ charges must be done separate from TeleMini v2.0, by soldering
+ them together or using some other connector.
+ </para>
+ <para>
+ The other lead from each pyro charge is then inserted into
+ the appropriate per-pyro channel screw terminal (top
+ terminal 1 for the Main charge, bottom terminal 1 for the
+ Apogee charge).
+ </para>
+ </section>
+ <section>
+ <title>Using an Active Switch with TeleMini v2.0</title>
+ <para>
+ As explained above, an external active switch requires three
+ connections, one to the positive battery terminal, one to
+ the flight computer positive input and one to ground. Use
+ the negative external battery connection, top terminal 4 for
+ ground.
+ </para>
+ <para>
+ The positive battery terminal is available on bottom
+ terminal 4, the positive flight computer input is on the
+ bottom terminal 3.
+ </para>
+ </section>
+ </section>
+ <section>
+ <title>EasyMini</title>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="easymini-top.jpg" width="5.5in" scalefit="1"/>
+ </imageobject>
+ </mediaobject>
+ </informalfigure>
+ <para>
+ EasyMini is built on a 0.8 inch by 1½ inch circuit board. It's
+ designed to fit in a 24mm coupler tube. The connectors and
+ screw terminals match TeleMini v2.0, so you can easily swap between
+ EasyMini and TeleMini.
+ </para>
+ <section>
+ <title>EasyMini Screw Terminals</title>
+ <para>
+ EasyMini has two sets of four screw terminals on the end of the
+ board opposite the telemetry antenna. Using the picture
+ above, the top four have connections for the main pyro
+ circuit and an external battery and the bottom four have
+ connections for the apogee pyro circuit and the power
+ switch. Counting from the left, the connections are as follows:
+ </para>
+ <table frame='all'>
+ <title>EasyMini Connections</title>
+ <?dbfo keep-together="always"?>
+ <tgroup cols='3' align='center' colsep='1' rowsep='1'>
+ <colspec align='center' colwidth='*' colname='Pin #'/>
+ <colspec align='center' colwidth='2*' colname='Pin Name'/>
+ <colspec align='left' colwidth='5*' colname='Description'/>
+ <thead>
+ <row>
+ <entry align='center'>Terminal #</entry>
+ <entry align='center'>Terminal Name</entry>
+ <entry align='center'>Description</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>Top 1</entry>
+ <entry>Main -</entry>
+ <entry>Main pyro channel connection to pyro circuit</entry>
+ </row>
+ <row>
+ <entry>Top 2</entry>
+ <entry>Main +</entry>
+ <entry>Main pyro channel common connection to battery +</entry>
+ </row>
+ <row>
+ <entry>Top 3</entry>
+ <entry>Battery +</entry>
+ <entry>Positive external battery terminal</entry>
+ </row>
+ <row>
+ <entry>Top 4</entry>
+ <entry>Battery -</entry>
+ <entry>Negative external battery terminal</entry>
+ </row>
+ <row>
+ <entry>Bottom 1</entry>
+ <entry>Apogee -</entry>
+ <entry>Apogee pyro channel connection to pyro circuit</entry>
+ </row>
+ <row>
+ <entry>Bottom 2</entry>
+ <entry>Apogee +</entry>
+ <entry>Apogee pyro channel common connection to
+ battery +</entry>
+ </row>
+ <row>
+ <entry>Bottom 3</entry>
+ <entry>Switch Output</entry>
+ <entry>Switch connection to flight computer</entry>
+ </row>
+ <row>
+ <entry>Bottom 4</entry>
+ <entry>Switch Input</entry>
+ <entry>Switch connection to positive battery terminal</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </section>
+ <section>
+ <title>Using a Separate Pyro Battery with EasyMini</title>
+ <para>
+ As described above, using an external pyro battery involves
+ connecting the negative battery terminal to the flight
+ computer ground, connecting the positive battery terminal to
+ one of the igniter leads and connecting the other igniter
+ lead to the per-channel pyro circuit connection.
+ </para>
+ <para>
+ To connect the negative pyro battery terminal to TeleMini
+ ground, connect it to the negative external battery
+ connection, top terminal 4.
+ </para>
+ <para>
+ Connecting the positive battery terminal to the pyro
+ charges must be done separate from EasyMini, by soldering
+ them together or using some other connector.
+ </para>
+ <para>
+ The other lead from each pyro charge is then inserted into
+ the appropriate per-pyro channel screw terminal (top
+ terminal 1 for the Main charge, bottom terminal 1 for the
+ Apogee charge).
+ </para>
+ </section>
+ <section>
+ <title>Using an Active Switch with EasyMini</title>
+ <para>
+ As explained above, an external active switch requires three
+ connections, one to the positive battery terminal, one to
+ the flight computer positive input and one to ground. Use
+ the negative external battery connection, top terminal 4 for
+ ground.
+ </para>
+ <para>
+ The positive battery terminal is available on bottom
+ terminal 4, the positive flight computer input is on the
+ bottom terminal 3.
+ </para>
+ </section>
+ </section>
+ <section>
+ <title>TeleMega</title>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="telemega-v1.0-top.jpg" width="5.5in" scalefit="1"/>
+ </imageobject>
+ </mediaobject>
+ </informalfigure>
+ <para>
+ TeleMega is a 1¼ inch by 3¼ inch circuit board. It was
+ designed to easily fit in a 38mm coupler. Like TeleMetrum,
+ TeleMega has an accelerometer and so it must be mounted so that
+ the board is aligned with the flight axis. It can be mounted
+ either antenna up or down.
+ </para>
+ <section>
+ <title>TeleMega Screw Terminals</title>
+ <para>
+ TeleMega has two sets of nine screw terminals on the end of
+ the board opposite the telemetry antenna. They are as follows:
+ </para>
+ <table frame='all'>
+ <title>TeleMega Screw Terminals</title>
+ <?dbfo keep-together="always"?>
+ <tgroup cols='3' align='center' colsep='1' rowsep='1'>
+ <colspec align='center' colwidth='*' colname='Pin #'/>
+ <colspec align='center' colwidth='2*' colname='Pin Name'/>
+ <colspec align='left' colwidth='5*' colname='Description'/>
+ <thead>
+ <row>
+ <entry align='center'>Terminal #</entry>
+ <entry align='center'>Terminal Name</entry>
+ <entry align='center'>Description</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>Top 1</entry>
+ <entry>Switch Input</entry>
+ <entry>Switch connection to positive battery terminal</entry>
+ </row>
+ <row>
+ <entry>Top 2</entry>
+ <entry>Switch Output</entry>
+ <entry>Switch connection to flight computer</entry>
+ </row>
+ <row>
+ <entry>Top 3</entry>
+ <entry>GND</entry>
+ <entry>Ground connection for use with external active switch</entry>
+ </row>
+ <row>
+ <entry>Top 4</entry>
+ <entry>Main -</entry>
+ <entry>Main pyro channel connection to pyro circuit</entry>
+ </row>
+ <row>
+ <entry>Top 5</entry>
+ <entry>Main +</entry>
+ <entry>Main pyro channel common connection to battery +</entry>
+ </row>
+ <row>
+ <entry>Top 6</entry>
+ <entry>Apogee -</entry>
+ <entry>Apogee pyro channel connection to pyro circuit</entry>
+ </row>
+ <row>
+ <entry>Top 7</entry>
+ <entry>Apogee +</entry>
+ <entry>Apogee pyro channel common connection to battery +</entry>
+ </row>
+ <row>
+ <entry>Top 8</entry>
+ <entry>D -</entry>
+ <entry>D pyro channel connection to pyro circuit</entry>
+ </row>
+ <row>
+ <entry>Top 9</entry>
+ <entry>D +</entry>
+ <entry>D pyro channel common connection to battery +</entry>
+ </row>
+ <row>
+ <entry>Bottom 1</entry>
+ <entry>GND</entry>
+ <entry>Ground connection for negative pyro battery terminal</entry>
+ </row>
+ <row>
+ <entry>Bottom 2</entry>
+ <entry>Pyro</entry>
+ <entry>Positive pyro battery terminal</entry>
+ </row>
+ <row>
+ <entry>Bottom 3</entry>
+ <entry>Lipo</entry>
+ <entry>
+ Power switch output. Use to connect main battery to
+ pyro battery input
+ </entry>
+ </row>
+ <row>
+ <entry>Bottom 4</entry>
+ <entry>A -</entry>
+ <entry>A pyro channel connection to pyro circuit</entry>
+ </row>
+ <row>
+ <entry>Bottom 5</entry>
+ <entry>A +</entry>
+ <entry>A pyro channel common connection to battery +</entry>
+ </row>
+ <row>
+ <entry>Bottom 6</entry>
+ <entry>B -</entry>
+ <entry>B pyro channel connection to pyro circuit</entry>
+ </row>
+ <row>
+ <entry>Bottom 7</entry>
+ <entry>B +</entry>
+ <entry>B pyro channel common connection to battery +</entry>
+ </row>
+ <row>
+ <entry>Bottom 8</entry>
+ <entry>C -</entry>
+ <entry>C pyro channel connection to pyro circuit</entry>
+ </row>
+ <row>
+ <entry>Bottom 9</entry>
+ <entry>C +</entry>
+ <entry>C pyro channel common connection to battery +</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </section>
+ <section>
+ <title>Using a Separate Pyro Battery with TeleMega</title>
+ <para>
+ TeleMega provides explicit support for an external pyro
+ battery. All that is required is to remove the jumper
+ between the lipo terminal (Bottom 3) and the pyro terminal
+ (Bottom 2). Then hook the negative pyro battery terminal to ground
+ (Bottom 1) and the positive pyro battery to the pyro battery
+ input (Bottom 2). You can then use the existing pyro screw
+ terminals to hook up all of the pyro charges.
+ </para>
+ </section>
+ <section>
+ <title>Using Only One Battery With TeleMega</title>
+ <para>
+ Because TeleMega has built-in support for a separate pyro
+ battery, if you want to fly with just one battery running
+ both the computer and firing the charges, you need to
+ connect the flight computer battery to the pyro
+ circuit. TeleMega has two screw terminals for this—hook a
+ wire from the Lipo terminal (Bottom 3) to the Pyro terminal
+ (Bottom 2).
+ </para>
+ </section>
+ <section>
+ <title>Using an Active Switch with TeleMega</title>
+ <para>
+ As explained above, an external active switch requires three
+ connections, one to the positive battery terminal, one to
+ the flight computer positive input and one to ground.
+ </para>
+ <para>
+ The positive battery terminal is available on Top terminal
+ 1, the positive flight computer input is on Top terminal
+ 2. Ground is on Top terminal 3.
+ </para>
+ </section>
+ </section>
+ <section>
+ <title>EasyMega</title>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="easymega-v1.0-top.jpg" width="4.5in" scalefit="1"/>
+ </imageobject>
+ </mediaobject>
+ </informalfigure>
+ <para>
+ EasyMega is a 1¼ inch by 2¼ inch circuit board. It was
+ designed to easily fit in a 38mm coupler. Like TeleMetrum,
+ EasyMega has an accelerometer and so it must be mounted so that
+ the board is aligned with the flight axis. It can be mounted
+ either antenna up or down.
+ </para>
+ <section>
+ <title>EasyMega Screw Terminals</title>
+ <para>
+ EasyMega has two sets of nine screw terminals on the end of
+ the board opposite the telemetry antenna. They are as follows:
+ </para>
+ <table frame='all'>
+ <title>EasyMega Screw Terminals</title>
+ <?dbfo keep-together="always"?>
+ <tgroup cols='3' align='center' colsep='1' rowsep='1'>
+ <colspec align='center' colwidth='*' colname='Pin #'/>
+ <colspec align='center' colwidth='2*' colname='Pin Name'/>
+ <colspec align='left' colwidth='5*' colname='Description'/>
+ <thead>
+ <row>
+ <entry align='center'>Terminal #</entry>
+ <entry align='center'>Terminal Name</entry>
+ <entry align='center'>Description</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>Top 1</entry>
+ <entry>Switch Input</entry>
+ <entry>Switch connection to positive battery terminal</entry>
+ </row>
+ <row>
+ <entry>Top 2</entry>
+ <entry>Switch Output</entry>
+ <entry>Switch connection to flight computer</entry>
+ </row>
+ <row>
+ <entry>Top 3</entry>
+ <entry>GND</entry>
+ <entry>Ground connection for use with external active switch</entry>
+ </row>
+ <row>
+ <entry>Top 4</entry>
+ <entry>Main -</entry>
+ <entry>Main pyro channel connection to pyro circuit</entry>
+ </row>
+ <row>
+ <entry>Top 5</entry>
+ <entry>Main +</entry>
+ <entry>Main pyro channel common connection to battery +</entry>
+ </row>
+ <row>
+ <entry>Top 6</entry>
+ <entry>Apogee -</entry>
+ <entry>Apogee pyro channel connection to pyro circuit</entry>
+ </row>
+ <row>
+ <entry>Top 7</entry>
+ <entry>Apogee +</entry>
+ <entry>Apogee pyro channel common connection to battery +</entry>
+ </row>
+ <row>
+ <entry>Top 8</entry>
+ <entry>D -</entry>
+ <entry>D pyro channel connection to pyro circuit</entry>
+ </row>
+ <row>
+ <entry>Top 9</entry>
+ <entry>D +</entry>
+ <entry>D pyro channel common connection to battery +</entry>
+ </row>
+ <row>
+ <entry>Bottom 1</entry>
+ <entry>GND</entry>
+ <entry>Ground connection for negative pyro battery terminal</entry>
+ </row>
+ <row>
+ <entry>Bottom 2</entry>
+ <entry>Pyro</entry>
+ <entry>Positive pyro battery terminal</entry>
+ </row>
+ <row>
+ <entry>Bottom 3</entry>
+ <entry>Lipo</entry>
+ <entry>
+ Power switch output. Use to connect main battery to
+ pyro battery input
+ </entry>
+ </row>
+ <row>
+ <entry>Bottom 4</entry>
+ <entry>A -</entry>
+ <entry>A pyro channel connection to pyro circuit</entry>
+ </row>
+ <row>
+ <entry>Bottom 5</entry>
+ <entry>A +</entry>
+ <entry>A pyro channel common connection to battery +</entry>
+ </row>
+ <row>
+ <entry>Bottom 6</entry>
+ <entry>B -</entry>
+ <entry>B pyro channel connection to pyro circuit</entry>
+ </row>
+ <row>
+ <entry>Bottom 7</entry>
+ <entry>B +</entry>
+ <entry>B pyro channel common connection to battery +</entry>
+ </row>
+ <row>
+ <entry>Bottom 8</entry>
+ <entry>C -</entry>
+ <entry>C pyro channel connection to pyro circuit</entry>
+ </row>
+ <row>
+ <entry>Bottom 9</entry>
+ <entry>C +</entry>
+ <entry>C pyro channel common connection to battery +</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </section>
+ <section>
+ <title>Using a Separate Pyro Battery with EasyMega</title>
+ <para>
+ EasyMega provides explicit support for an external pyro
+ battery. All that is required is to remove the jumper
+ between the lipo terminal (Bottom 3) and the pyro terminal
+ (Bottom 2). Then hook the negative pyro battery terminal to ground
+ (Bottom 1) and the positive pyro battery to the pyro battery
+ input (Bottom 2). You can then use the existing pyro screw
+ terminals to hook up all of the pyro charges.
+ </para>
+ </section>
+ <section>
+ <title>Using Only One Battery With EasyMega</title>
+ <para>
+ Because EasyMega has built-in support for a separate pyro
+ battery, if you want to fly with just one battery running
+ both the computer and firing the charges, you need to
+ connect the flight computer battery to the pyro
+ circuit. EasyMega has two screw terminals for this—hook a
+ wire from the Lipo terminal (Bottom 3) to the Pyro terminal
+ (Bottom 2).
+ </para>
+ </section>
+ <section>
+ <title>Using an Active Switch with EasyMega</title>
+ <para>
+ As explained above, an external active switch requires three
+ connections, one to the positive battery terminal, one to
+ the flight computer positive input and one to ground.
+ </para>
+ <para>
+ The positive battery terminal is available on Top terminal
+ 1, the positive flight computer input is on Top terminal
+ 2. Ground is on Top terminal 3.
+ </para>
+ </section>
+ </section>
+ <section>
+ <title>Flight Data Recording</title>
+ <para>
+ Each flight computer logs data at 100 samples per second
+ during ascent and 10 samples per second during descent, except
+ for TeleMini v1.0, which records ascent at 10 samples per
+ second and descent at 1 sample per second. Data are logged to
+ an on-board flash memory part, which can be partitioned into
+ several equal-sized blocks, one for each flight.
+ </para>
+ <table frame='all'>
+ <title>Data Storage on Altus Metrum altimeters</title>
+ <?dbfo keep-together="always"?>
+ <tgroup cols='4' align='center' colsep='1' rowsep='1'>
+ <colspec align='center' colwidth='*' colname='Device'/>
+ <colspec align='center' colwidth='*' colname='Bytes per sample'/>
+ <colspec align='center' colwidth='*' colname='Total storage'/>
+ <colspec align='center' colwidth='*' colname='Minutes of
+ full-rate'/>
+ <thead>
+ <row>
+ <entry align='center'>Device</entry>
+ <entry align='center'>Bytes per Sample</entry>
+ <entry align='center'>Total Storage</entry>
+ <entry align='center'>Minutes at Full Rate</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>TeleMetrum v1.0</entry>
+ <entry>8</entry>
+ <entry>1MB</entry>
+ <entry>20</entry>
+ </row>
+ <row>
+ <entry>TeleMetrum v1.1 v1.2</entry>
+ <entry>8</entry>
+ <entry>2MB</entry>
+ <entry>40</entry>
+ </row>
+ <row>
+ <entry>TeleMetrum v2.0</entry>
+ <entry>16</entry>
+ <entry>8MB</entry>
+ <entry>80</entry>
+ </row>
+ <row>
+ <entry>TeleMini v1.0</entry>
+ <entry>2</entry>
+ <entry>5kB</entry>
+ <entry>4</entry>
+ </row>
+ <row>
+ <entry>TeleMini v2.0</entry>
+ <entry>16</entry>
+ <entry>1MB</entry>
+ <entry>10</entry>
+ </row>
+ <row>
+ <entry>EasyMini</entry>
+ <entry>16</entry>
+ <entry>1MB</entry>
+ <entry>10</entry>
+ </row>
+ <row>
+ <entry>TeleMega</entry>
+ <entry>32</entry>
+ <entry>8MB</entry>
+ <entry>40</entry>
+ </row>
+ <row>
+ <entry>EasyMega</entry>
+ <entry>32</entry>
+ <entry>8MB</entry>
+ <entry>40</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ <para>
+ The on-board flash is partitioned into separate flight logs,
+ each of a fixed maximum size. Increase the maximum size of
+ each log and you reduce the number of flights that can be
+ stored. Decrease the size and you can store more flights.
+ </para>
+ <para>
+ Configuration data is also stored in the flash memory on
+ TeleMetrum v1.x, TeleMini and EasyMini. This consumes 64kB
+ of flash space. This configuration space is not available
+ for storing flight log data. TeleMetrum v2.0, TeleMega and EasyMega
+ store configuration data in a bit of eeprom available within
+ the processor chip, leaving that space available in flash for
+ more flight data.
+ </para>
+ <para>
+ To compute the amount of space needed for a single flight, you
+ can multiply the expected ascent time (in seconds) by 100
+ times bytes-per-sample, multiply the expected descent time (in
+ seconds) by 10 times the bytes per sample and add the two
+ together. That will slightly under-estimate the storage (in
+ bytes) needed for the flight. For instance, a TeleMetrum v2.0 flight spending
+ 20 seconds in ascent and 150 seconds in descent will take
+ about (20 * 1600) + (150 * 160) = 56000 bytes of storage. You
+ could store dozens of these flights in the on-board flash.
+ </para>
+ <para>
+ The default size allows for several flights on each flight
+ computer, except for TeleMini v1.0, which only holds data for a
+ single flight. You can adjust the size.
+ </para>
+ <para>
+ Altus Metrum flight computers will not overwrite existing
+ flight data, so be sure to download flight data and erase it
+ from the flight computer before it fills up. The flight
+ computer will still successfully control the flight even if it
+ cannot log data, so the only thing you will lose is the data.
+ </para>
+ </section>
+ <section>
+ <title>Installation</title>
+ <para>
+ A typical installation involves attaching
+ only a suitable battery, a single pole switch for
+ power on/off, and two pairs of wires connecting e-matches for the
+ apogee and main ejection charges. All Altus Metrum products are
+ designed for use with single-cell batteries with 3.7 volts
+ nominal. TeleMini v2.0 and EasyMini may also be used with other
+ batteries as long as they supply between 4 and 12 volts.
+ </para>
+ <para>
+ The battery connectors are a standard 2-pin JST connector and
+ match batteries sold by Spark Fun. These batteries are
+ single-cell Lithium Polymer batteries that nominally provide 3.7
+ volts. Other vendors sell similar batteries for RC aircraft
+ using mating connectors, however the polarity for those is
+ generally reversed from the batteries used by Altus Metrum
+ products. In particular, the Tenergy batteries supplied for use
+ in Featherweight flight computers are not compatible with Altus
+ Metrum flight computers or battery chargers. <emphasis>Check
+ polarity and voltage before connecting any battery not purchased
+ from Altus Metrum or Spark Fun.</emphasis>
+ </para>
+ <para>
+ By default, we use the unregulated output of the 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, check out the “External Pyro Battery” section in this
+ manual for instructions on how to wire that up. The altimeters are
+ designed to work with an external pyro battery of no more than 15 volts.
+ </para>
+ <para>
+ Ejection charges are wired directly to the screw terminal block
+ at the aft end of the altimeter. You'll need a very small straight
+ blade screwdriver for these screws, such as you might find in a
+ jeweler's screwdriver set.
+ </para>
+ <para>
+ Except for TeleMini v1.0, the flight computers also use the
+ screw terminal block for the power switch leads. On TeleMini v1.0,
+ the power switch leads are soldered directly to the board and
+ can be connected directly to a switch.
+ </para>
+ <para>
+ For most air-frames, the integrated antennas are more than
+ adequate. However, if you are installing in a carbon-fiber or
+ metal electronics bay which is opaque to RF signals, you may need to
+ use off-board external antennas instead. In this case, you can
+ replace the stock UHF antenna wire with an edge-launched SMA connector,
+ and, on TeleMetrum v1, you can unplug the integrated GPS
+ antenna and select an appropriate off-board GPS antenna with
+ cable terminating in a U.FL connector.
+ </para>
+ </section>
+ </chapter>
+ <chapter>
+ <title>System Operation</title>
+ <section>
+ <title>Firmware Modes </title>
+ <para>
+ The AltOS firmware build for the altimeters has two
+ fundamental modes, “idle” and “flight”. Which of these modes
+ the firmware operates in is determined at start up time. For
+ TeleMetrum, TeleMega and EasyMega, which have accelerometers, the mode is
+ controlled 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
+ the flight computer 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. Since TeleMini v2.0 and EasyMini don't have an
+ accelerometer we can use to determine orientation, “idle” mode
+ is selected if the board is connected via USB to a computer,
+ otherwise the board enters “flight” mode. TeleMini v1.0
+ selects “idle” mode if it receives a command packet within the
+ first five seconds of operation.
+ </para>
+ <para>
+ At power on, the altimeter will beep out the battery voltage
+ to the nearest tenth of a volt. Each digit is represented by
+ a sequence of short “dit” beeps, with a pause between
+ digits. A zero digit is represented with one long “dah”
+ beep. Then there will be a short pause while the altimeter
+ completes initialization and self test, and decides which mode
+ to enter next.
+ </para>
+ <para>
+ Here's a short summary of all of the modes and the beeping (or
+ flashing, in the case of TeleMini v1) that accompanies each
+ mode. In the description of the beeping pattern, “dit” means a
+ short beep while "dah" means a long beep (three times as
+ long). “Brap” means a long dissonant tone.
+ <table frame='all'>
+ <title>AltOS Modes</title>
+ <?dbfo keep-together="always"?>
+ <tgroup cols='4' align='center' colsep='1' rowsep='1'>
+ <colspec align='center' colwidth='*' colname='Mode Name'/>
+ <colspec align='center' colwidth='*' colname='Letter'/>
+ <colspec align='center' colwidth='*' colname='Beeps'/>
+ <colspec align='center' colwidth='*' colname='Description'/>
+ <thead>
+ <row>
+ <entry>Mode Name</entry>
+ <entry>Abbreviation</entry>
+ <entry>Beeps</entry>
+ <entry>Description</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>Startup</entry>
+ <entry>S</entry>
+ <entry>battery voltage in decivolts</entry>
+ <entry>
+ <para>
+ Calibrating sensors, detecting orientation.
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>Idle</entry>
+ <entry>I</entry>
+ <entry>dit dit</entry>
+ <entry>
+ <para>
+ Ready to accept commands over USB or radio link.
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>Pad</entry>
+ <entry>P</entry>
+ <entry>dit dah dah dit</entry>
+ <entry>
+ <para>
+ Waiting for launch. Not listening for commands.
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>Boost</entry>
+ <entry>B</entry>
+ <entry>dah dit dit dit</entry>
+ <entry>
+ <para>
+ Accelerating upwards.
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>Fast</entry>
+ <entry>F</entry>
+ <entry>dit dit dah dit</entry>
+ <entry>
+ <para>
+ Decelerating, but moving faster than 200m/s.
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>Coast</entry>
+ <entry>C</entry>
+ <entry>dah dit dah dit</entry>
+ <entry>
+ <para>
+ Decelerating, moving slower than 200m/s
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>Drogue</entry>
+ <entry>D</entry>
+ <entry>dah dit dit</entry>
+ <entry>
+ <para>
+ Descending after apogee. Above main height.
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>Main</entry>
+ <entry>M</entry>
+ <entry>dah dah</entry>
+ <entry>
+ <para>
+ Descending. Below main height.
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>Landed</entry>
+ <entry>L</entry>
+ <entry>dit dah dit dit</entry>
+ <entry>
+ <para>
+ Stable altitude for at least ten seconds.
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>Sensor error</entry>
+ <entry>X</entry>
+ <entry>dah dit dit dah</entry>
+ <entry>
+ <para>
+ Error detected during sensor calibration.
+ </para>
+ </entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </para>
+ <para>
+ In flight or “pad” mode, the altimeter engages the flight
+ state machine, goes into transmit-only mode to send telemetry,
+ and waits for launch to be detected. Flight mode is indicated
+ by an “di-dah-dah-dit” (“P” for pad) on the beeper or lights,
+ followed by beeps or flashes indicating the state of the
+ pyrotechnic igniter continuity. One beep/flash indicates
+ apogee continuity, two beeps/flashes indicate main continuity,
+ three beeps/flashes indicate both apogee and main continuity,
+ and one longer “brap” sound which is made by rapidly
+ alternating between two tones indicates no continuity. For a
+ dual deploy flight, make sure you're getting three beeps or
+ flashes before launching! For apogee-only or motor eject
+ flights, do what makes sense.
+ </para>
+ <para>
+ If idle mode is entered, you will hear an audible “di-dit” or
+ see two short flashes (“I” for idle), and the flight state
+ machine is disengaged, thus no ejection charges will fire.
+ The altimeters also listen for the radio link when in idle
+ mode for requests sent via TeleDongle. Commands can be issued
+ in idle mode over either USB or the radio link
+ equivalently. TeleMini v1.0 only has the radio link. Idle
+ mode is useful for configuring the altimeter, for extracting
+ data from the on-board storage chip after flight, and for
+ ground testing pyro charges.
+ </para>
+ <para>
+ In “Idle” and “Pad” modes, once the mode indication
+ beeps/flashes and continuity indication has been sent, if
+ there is no space available to log the flight in on-board
+ memory, the flight computer will emit a warbling tone (much
+ slower than the “no continuity tone”)
+ </para>
+ <para>
+ Here's a summary of all of the “pad” and “idle” mode indications.
+ <table frame='all'>
+ <title>Pad/Idle Indications</title>
+ <?dbfo keep-together="always"?>
+ <tgroup cols='3' align='center' colsep='1' rowsep='1'>
+ <colspec align='center' colwidth='*' colname='Name'/>
+ <colspec align='center' colwidth='*' colname='Beeps'/>
+ <colspec align='center' colwidth='*' colname='Description'/>
+ <thead>
+ <row>
+ <entry>Name</entry>
+ <entry>Beeps</entry>
+ <entry>Description</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>Neither</entry>
+ <entry>brap</entry>
+ <entry>
+ <para>
+ No continuity detected on either apogee or main
+ igniters.
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>Apogee</entry>
+ <entry>dit</entry>
+ <entry>
+ <para>
+ Continuity detected only on apogee igniter.
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>Main</entry>
+ <entry>dit dit</entry>
+ <entry>
+ <para>
+ Continuity detected only on main igniter.
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>Both</entry>
+ <entry>dit dit dit</entry>
+ <entry>
+ <para>
+ Continuity detected on both igniters.
+ </para>
+ </entry>
+ </row>
+ <row>
+ <entry>Storage Full</entry>
+ <entry>warble</entry>
+ <entry>
+ <para>
+ On-board data logging storage is full. This will
+ not prevent the flight computer from safely
+ controlling the flight or transmitting telemetry
+ signals, but no record of the flight will be
+ stored in on-board flash.
+ </para>
+ </entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </para>
+ <para>
+ Once landed, the flight computer will signal that by emitting
+ the “Landed” sound described above, after which it will beep
+ out the apogee height (in meters). Each digit is represented
+ by a sequence of short “dit” beeps, with a pause between
+ digits. A zero digit is represented with one long “dah”
+ beep. The flight computer will continue to report landed mode
+ and beep out the maximum height until turned off.
+ </para>
+ <para>
+ One “neat trick” of particular value when TeleMetrum, TeleMega
+ or EasyMega are used with
+ very large air-frames, 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 air-frame to launch position, and issue a 'reset' command
+ via TeleDongle over the radio link to cause the altimeter to reboot and
+ come up in 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>
+ <para>
+ TeleMini v1.0 is configured solely via the radio link. Of course, that
+ means you need to know the TeleMini radio configuration values
+ or you won't be able to communicate with it. For situations
+ when you don't have the radio configuration values, TeleMini v1.0
+ offers an 'emergency recovery' mode. In this mode, TeleMini is
+ configured as follows:
+ <itemizedlist>
+ <listitem>
+ <para>
+ Sets the radio frequency to 434.550MHz
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Sets the radio calibration back to the factory value.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Sets the callsign to N0CALL
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Does not go to 'pad' mode after five seconds.
+ </para>
+ </listitem>
+ </itemizedlist>
+ </para>
+ <para>
+ To get into 'emergency recovery' mode, first find the row of
+ four small holes opposite the switch wiring. Using a short
+ piece of small gauge wire, connect the outer two holes
+ together, then power TeleMini up. Once the red LED is lit,
+ disconnect the wire and the board should signal that it's in
+ 'idle' mode after the initial five second startup period.
+ </para>
+ </section>
+ <section>
+ <title>GPS </title>
+ <para>
+ TeleMetrum and TeleMega include a complete GPS receiver. A
+ complete explanation of how GPS works is beyond the scope of
+ this manual, but the bottom line is that the 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>
+ The flight computers provide backup power to the GPS chip any time a
+ battery is connected. This allows the receiver to “warm start” on
+ the launch rail much faster than if every power-on were a GPS
+ “cold start”. In typical operations, powering up
+ on the flight line in idle mode while performing final air-frame
+ 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>Controlling An Altimeter Over The Radio Link</title>
+ <para>
+ One of the unique features of the Altus Metrum system is the
+ ability to create a two way command link between TeleDongle
+ and an altimeter using the digital radio transceivers
+ built into each device. This allows you to interact with the
+ altimeter from afar, as if it were directly connected to the
+ computer.
+ </para>
+ <para>
+ Any operation which can be performed with a flight computer can
+ either be done with the device directly connected to the
+ computer via the USB cable, or through the radio
+ link. TeleMini v1.0 doesn't provide a USB connector and so it is
+ always communicated with over radio. Select the appropriate
+ TeleDongle device when the list of devices is presented and
+ AltosUI will interact with an altimeter over the radio link.
+ </para>
+ <para>
+ One oddity in the current interface is how AltosUI selects the
+ frequency for radio communications. Instead of providing
+ an interface to specifically configure the frequency, it uses
+ whatever frequency was most recently selected for the target
+ TeleDongle device in Monitor Flight mode. If you haven't ever
+ used that mode with the TeleDongle in question, select the
+ Monitor Flight button from the top level UI, and pick the
+ appropriate TeleDongle device. Once the flight monitoring
+ window is open, select the desired frequency and then close it
+ down again. All radio communications will now use that frequency.
+ </para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ Save Flight Data—Recover flight data from the rocket without
+ opening it up.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Configure altimeter apogee delays, main deploy heights
+ and additional pyro event conditions
+ to respond to changing launch conditions. You can also
+ 'reboot' the altimeter. Use this to remotely enable the
+ flight computer by turning TeleMetrum or TeleMega on in “idle” mode,
+ then once the air-frame is oriented for launch, you can
+ reboot the altimeter 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 air-frame. Simply assemble the
+ rocket as if for flight with the apogee and main charges
+ loaded, then remotely command the altimeter to fire the
+ igniters.
+ </para>
+ </listitem>
+ </itemizedlist>
+ <para>
+ Operation over the radio link for configuring an altimeter, ground
+ testing igniters, and so forth uses the same RF frequencies as flight
+ telemetry. To configure the desired TeleDongle frequency, select
+ the monitor flight tab, then use the frequency selector and
+ close the window before performing other desired radio operations.
+ </para>
+ <para>
+ The flight computers only enable radio commanding in 'idle' mode.
+ TeleMetrum and TeleMega use the accelerometer to detect which orientation they
+ start up in, so make sure you have the flight computer lying horizontally when you turn
+ it on. Otherwise, it will start in 'pad' mode ready for
+ flight, and will not be listening for command packets from TeleDongle.
+ </para>
+ <para>
+ TeleMini listens for a command packet for five seconds after
+ first being turned on, if it doesn't hear anything, it enters
+ 'pad' mode, ready for flight and will no longer listen for
+ command packets. The easiest way to connect to TeleMini is to
+ initiate the command and select the TeleDongle device. At this
+ point, the TeleDongle will be attempting to communicate with
+ the TeleMini. Now turn TeleMini on, and it should immediately
+ start communicating with the TeleDongle and the desired
+ operation can be performed.
+ </para>
+ <para>
+ You can monitor the operation of the radio link by watching the
+ lights on the devices. The red LED will flash each time a packet
+ is transmitted, while the green LED will light up on TeleDongle when
+ it is waiting to receive a packet from the altimeter.
+ </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 radio link central to the Altus Metrum system,
+ this can be accomplished in a TeleMega, TeleMetrum or TeleMini equipped rocket
+ with less work than you may be accustomed to with other systems. It
+ can even be fun!
+ </para>
+ <para>
+ Just prep the rocket for flight, then power up the altimeter
+ in “idle” mode (placing air-frame horizontal for TeleMetrum or TeleMega, or
+ selecting the Configure Altimeter tab for TeleMini). 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. You can now command the altimeter to fire the apogee
+ or main charges from a safe distance using your computer and
+ TeleDongle and the Fire Igniter tab to complete ejection testing.
+ </para>
+ </section>
+ <section>
+ <title>Radio Link </title>
+ <para>
+ Our flight computers all incorporate 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, the altimeter firmware listens for the radio link when
+ it's in “idle mode”, which
+ allows us to use the radio link to configure the rocket, do things like
+ ejection tests, and extract data after a flight without having to
+ crack open the air-frame. However, when the board is in “flight
+ mode”, the altimeter 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 through
+ the radio in case the rocket crashes and we aren't able to extract
+ data later...
+ </para>
+ <para>
+ We don't generally use a 'normal packet radio' mode like APRS
+ because they're just too inefficient. The GFSK modulation we
+ use is FSK with the base-band pulses passed through a Gaussian
+ filter before they go into the modulator to limit the
+ transmitted bandwidth. When combined with forward error
+ correction and interleaving, this allows us to have a very
+ robust 19.2 kilobit data link with only 10-40 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 great reception, and calculations suggest we should be
+ good to well over 40k feet AGL with a 5-element yagi on the
+ ground with our 10mW units and over 100k feet AGL with the
+ 40mW devices. We hope to fly boards to higher altitudes over
+ time, and would of course appreciate customer feedback on
+ performance in higher altitude flights!
+ </para>
+ </section>
+ <section>
+ <title>APRS</title>
+ <para>
+ TeleMetrum v2.0 and TeleMega can send APRS if desired, and the
+ interval between APRS packets can be configured. As each APRS
+ packet takes a full second to transmit, we recommend an
+ interval of at least 5 seconds to avoid consuming too much
+ battery power or radio channel bandwidth. You can configure
+ the APRS interval using AltosUI; that process is described in
+ the Configure Altimeter section of the AltosUI chapter.
+ </para>
+ <para>
+ AltOS uses the APRS compressed position report data format,
+ which provides for higher position precision and shorter
+ packets than the original APRS format. It also includes
+ altitude data, which is invaluable when tracking rockets. We
+ haven't found a receiver which doesn't handle compressed
+ positions, but it's just possible that you have one, so if you
+ have an older device that can receive the raw packets but
+ isn't displaying position information, it's possible that this
+ is the cause.
+ </para>
+ <para>
+ APRS packets include an SSID (Secondary Station Identifier)
+ field that allows one operator to have multiple
+ transmitters. AltOS allows you to set this to a single digit
+ from 0 to 9, allowing you to fly multiple transmitters at the
+ same time while keeping the identify of each one separate in
+ the receiver. By default, the SSID is set to the last digit of
+ the device serial number.
+ </para>
+ <para>
+ The APRS packet format includes a comment field that can have
+ arbitrary text in it. AltOS uses this to send status
+ information about the flight computer. It sends four fields as
+ shown in the following table.
+ </para>
+ <table frame='all'>
+ <title>Altus Metrum APRS Comments</title>
+ <?dbfo keep-together="always"?>
+ <tgroup cols='3' align='center' colsep='1' rowsep='1'>
+ <colspec align='center' colwidth='*' colname='Field'/>
+ <colspec align='center' colwidth='*' colname='Example'/>
+ <colspec align='center' colwidth='4*' colname='Description'/>
+ <thead>
+ <row>
+ <entry align='center'>Field</entry>
+ <entry align='center'>Example</entry>
+ <entry align='center'>Description</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>1</entry>
+ <entry>L</entry>
+ <entry>GPS Status U for unlocked, L for locked</entry>
+ </row>
+ <row>
+ <entry>2</entry>
+ <entry>6</entry>
+ <entry>Number of Satellites in View</entry>
+ </row>
+ <row>
+ <entry>3</entry>
+ <entry>B4.0</entry>
+ <entry>Altimeter Battery Voltage</entry>
+ </row>
+ <row>
+ <entry>4</entry>
+ <entry>A3.7</entry>
+ <entry>Apogee Igniter Voltage</entry>
+ </row>
+ <row>
+ <entry>5</entry>
+ <entry>M3.7</entry>
+ <entry>Main Igniter Voltage</entry>
+ </row>
+ <row>
+ <entry>6</entry>
+ <entry>1286</entry>
+ <entry>Device Serial Number</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ <para>
+ Here's an example of an APRS comment showing GPS lock with 6
+ satellites in view, a primary battery at 4.0V, and
+ apogee and main igniters both at 3.7V from device 1286.
+ <screen>
+ L6 B4.0 A3.7 M3.7 1286
+ </screen>
+ </para>
+ <para>
+ Make sure your primary battery is above 3.8V, any connected
+ igniters are above 3.5V and GPS is locked with at least 5 or 6
+ satellites in view before flying. If GPS is switching between
+ L and U regularly, then it doesn't have a good lock and you
+ should wait until it becomes stable.
+ </para>
+ <para>
+ If the GPS receiver loses lock, the APRS data transmitted will
+ contain the last position for which GPS lock was
+ available. You can tell that this has happened by noticing
+ that the GPS status character switches from 'L' to 'U'. Before
+ GPS has locked, APRS will transmit zero for latitude,
+ longitude and altitude.
+ </para>
+ </section>
+ <section>
+ <title>Configurable Parameters</title>
+ <para>
+ Configuring an Altus Metrum altimeter for flight is very
+ simple. Even on our baro-only TeleMini and EasyMini boards,
+ the use of a Kalman filter means there is no need to set a
+ “mach delay”. The few configurable parameters can all be set
+ using AltosUI over USB or or radio link via TeleDongle. Read
+ the Configure Altimeter section in the AltosUI chapter below
+ for more information.
+ </para>
+ <section>
+ <title>Radio Frequency</title>
+ <para>
+ Altus Metrum boards support radio frequencies in the 70cm
+ band. By default, the configuration interface provides a
+ list of 10 “standard” frequencies in 100kHz channels starting at
+ 434.550MHz. However, the firmware supports use of
+ any 50kHz multiple within the 70cm band. At any given
+ launch, we highly recommend coordinating when and by whom each
+ frequency will be used to avoid interference. And of course, both
+ altimeter and TeleDongle must be configured to the same
+ frequency to successfully communicate with each other.
+ </para>
+ </section>
+ <section>
+ <title>Callsign</title>
+ <para>
+ This sets the callsign used for telemetry, APRS and the
+ packet link. For telemetry and APRS, this is used to
+ identify the device. For the packet link, the callsign must
+ match that configured in AltosUI or the link will not
+ work. This is to prevent accidental configuration of another
+ Altus Metrum flight computer operating on the same frequency nearby.
+ </para>
+ </section>
+ <section>
+ <title>Telemetry/RDF/APRS Enable</title>
+ <para>
+ You can completely disable the radio while in flight, if
+ necessary. This doesn't disable the packet link in idle
+ mode.
+ </para>
+ </section>
+ <section>
+ <title>Telemetry baud rate</title>
+ <para>
+ This sets the modulation bit rate for data transmission for
+ both telemetry and packet link mode. Lower bit
+ rates will increase range while reducing the amount of data
+ that can be sent and increasing battery consumption. All
+ telemetry is done using a rate 1/2 constraint 4 convolution
+ code, so the actual data transmission rate is 1/2 of the
+ modulation bit rate specified here.
+ </para>
+ </section>
+ <section>
+ <title>APRS Interval</title>
+ <para>
+ This selects how often APRS packets are transmitted. Set
+ this to zero to disable APRS without also disabling the
+ regular telemetry and RDF transmissions. As APRS takes a
+ full second to transmit a single position report, we
+ recommend sending packets no more than once every 5 seconds.
+ </para>
+ </section>
+ <section>
+ <title>APRS SSID</title>
+ <para>
+ This selects the SSID reported in APRS packets. By default,
+ it is set to the last digit of the serial number, but you
+ can change this to any value from 0 to 9.
+ </para>
+ </section>
+ <section>
+ <title>Apogee Delay</title>
+ <para>
+ Apogee delay is the number of seconds after the altimeter 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>
+ The Altus Metrum apogee detection algorithm fires exactly at
+ 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 air-frames this
+ way quite happily, including Keith's successful L3 cert.
+ </para>
+ </section>
+ <section>
+ <title>Apogee Lockout</title>
+ <para>
+ Apogee lockout is the number of seconds after boost where
+ the flight computer will not fire the apogee charge, even if
+ the rocket appears to be at apogee. This is often called
+ 'Mach Delay', as it is intended to prevent a flight computer
+ from unintentionally firing apogee charges due to the pressure
+ spike that occurrs across a mach transition. Altus Metrum
+ flight computers include a Kalman filter which is not fooled
+ by this sharp pressure increase, and so this setting should
+ be left at the default value of zero to disable it.
+ </para>
+ </section>
+ <section>
+ <title>Main Deployment Altitude</title>
+ <para>
+ By default, the altimeter 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 air-frames, 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>
+ </section>
+ <section>
+ <title>Maximum Flight Log</title>
+ <para>
+ Changing this value will set the maximum amount of flight
+ log storage that an individual flight will use. The
+ available storage is divided into as many flights of the
+ specified size as can fit in the available space. You can
+ download and erase individual flight logs. If you fill up
+ the available storage, future flights will not get logged
+ until you erase some of the stored ones.
+ </para>
+ <para>
+ Even though our flight computers (except TeleMini v1.0) can store
+ multiple flights, we strongly recommend downloading and saving
+ flight data after each flight.
+ </para>
+ </section>
+ <section>
+ <title>Ignite Mode</title>
+ <para>
+ Instead of firing one charge at apogee and another charge at
+ a fixed height above the ground, you can configure the
+ altimeter to fire both at apogee or both during
+ descent. This was added to support an airframe Bdale designed that
+ had two altimeters, one in the fin can and one in the nose.
+ </para>
+ <para>
+ Providing the ability to use both igniters for apogee or
+ main allows some level of redundancy without needing two
+ flight computers. In Redundant Apogee or Redundant Main
+ mode, the two charges will be fired two seconds apart.
+ </para>
+ </section>
+ <section>
+ <title>Pad Orientation</title>
+ <para>
+ TeleMetrum, TeleMega and EasyMega measure acceleration along the axis
+ of the board. Which way the board is oriented affects the
+ sign of the acceleration value. Instead of trying to guess
+ which way the board is mounted in the air frame, the
+ altimeter must be explicitly configured for either Antenna
+ Up or Antenna Down. The default, Antenna Up, expects the end
+ of the board connected to the 70cm antenna to be nearest the
+ nose of the rocket, with the end containing the screw
+ terminals nearest the tail.
+ </para>
+ </section>
+ <section>
+ <title>Configurable Pyro Channels</title>
+ <para>
+ In addition to the usual Apogee and Main pyro channels,
+ TeleMega and EasyMega have four additional channels that can be configured
+ to activate when various flight conditions are
+ satisfied. You can select as many conditions as necessary;
+ all of them must be met in order to activate the
+ channel. The conditions available are:
+ </para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ Acceleration away from the ground. Select a value, and
+ then choose whether acceleration should be above or
+ below that value. Acceleration is positive upwards, so
+ accelerating towards the ground would produce negative
+ numbers. Acceleration during descent is noisy and
+ inaccurate, so be careful when using it during these
+ phases of the flight.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Vertical speed. Select a value, and then choose whether
+ vertical speed should be above or below that
+ value. Speed is positive upwards, so moving towards the
+ ground would produce negative numbers. Speed during
+ descent is a bit noisy and so be careful when using it
+ during these phases of the flight.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Height. Select a value, and then choose whether the
+ height above the launch pad should be above or below
+ that value.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Orientation. TeleMega and EasyMega contain a 3-axis gyroscope and
+ accelerometer which is used to measure the current
+ angle. Note that this angle is not the change in angle
+ from the launch pad, but rather absolute relative to
+ gravity; the 3-axis accelerometer is used to compute the
+ angle of the rocket on the launch pad and initialize the
+ system. Because this value is computed by integrating
+ rate gyros, it gets progressively less accurate as the
+ flight goes on. It should have an accumulated error of
+ less than 0.2°/second (after 10 seconds of flight, the
+ error should be less than 2°).
+ </para>
+ <para>
+ The usual use of the orientation configuration is to
+ ensure that the rocket is traveling mostly upwards when
+ deciding whether to ignite air starts or additional
+ stages. For that, choose a reasonable maximum angle
+ (like 20°) and set the motor igniter to require an angle
+ of less than that value.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Flight Time. Time since boost was detected. Select a
+ value and choose whether to activate the pyro channel
+ before or after that amount of time.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Ascending. A simple test saying whether the rocket is
+ going up or not. This is exactly equivalent to testing
+ whether the speed is > 0.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Descending. A simple test saying whether the rocket is
+ going down or not. This is exactly equivalent to testing
+ whether the speed is < 0.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ After Motor. The flight software counts each time the
+ rocket starts accelerating and then decelerating
+ (presumably due to a motor or motors burning). Use this
+ value for multi-staged or multi-airstart launches.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Delay. This value doesn't perform any checks, instead it
+ inserts a delay between the time when the other
+ parameters become true and when the pyro channel is
+ activated.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Flight State. The flight software tracks the flight
+ through a sequence of states:
+ <orderedlist>
+ <listitem>
+ <para>
+ Boost. The motor has lit and the rocket is
+ accelerating upwards.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Fast. The motor has burned out and the rocket is
+ decelerating, but it is going faster than 200m/s.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Coast. The rocket is still moving upwards and
+ decelerating, but the speed is less than 200m/s.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Drogue. The rocket has reached apogee and is heading
+ back down, but is above the configured Main
+ altitude.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Main. The rocket is still descending, and is below
+ the Main altitude
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Landed. The rocket is no longer moving.
+ </para>
+ </listitem>
+ </orderedlist>
+ </para>
+ <para>
+ You can select a state to limit when the pyro channel
+ may activate; note that the check is based on when the
+ rocket transitions <emphasis>into</emphasis> the state, and so checking for
+ “greater than Boost” means that the rocket is currently
+ in boost or some later state.
+ </para>
+ <para>
+ When a motor burns out, the rocket enters either Fast or
+ Coast state (depending on how fast it is moving). If the
+ computer detects upwards acceleration again, it will
+ move back to Boost state.
+ </para>
+ </listitem>
+ </itemizedlist>
+ </section>
+ </section>
+
+ </chapter>
+ <chapter>
+ <title>AltosUI</title>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="altosui.png" width="4.6in"/>
+ </imageobject>
+ </mediaobject>
+ </informalfigure>
+ <para>
+ The AltosUI program provides a graphical user interface for
+ interacting with the Altus Metrum product family. AltosUI can
+ monitor telemetry data, configure devices and many other
+ tasks. The primary interface window provides a selection of
+ buttons, one for each major activity in the system. This chapter
+ is split into sections, each of which documents one of the tasks
+ provided from the top-level toolbar.
+ </para>
+ <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>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="device-selection.png" width="3.1in"/>
+ </imageobject>
+ </mediaobject>
+ </informalfigure>
+ <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 frequency being monitored by the TeleDongle device is
+ displayed at the top of the window. You can configure the
+ frequency by clicking on the frequency box and selecting the desired
+ frequency. AltosUI remembers the last frequency selected for each
+ TeleDongle and selects that automatically the next time you use
+ that device.
+ </para>
+ <para>
+ Below the TeleDongle frequency selector, the window contains a few
+ significant pieces of information about the altimeter providing
+ the telemetry data stream:
+ </para>
+ <itemizedlist>
+ <listitem>
+ <para>The configured call-sign</para>
+ </listitem>
+ <listitem>
+ <para>The device serial number</para>
+ </listitem>
+ <listitem>
+ <para>The flight number. Each altimeter 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. At
+ the default data rate, 38400 bps, in bench testing, the
+ radio inside TeleDongle v0.2 operates down to about
+ -106dBm, while the v3 radio works down to about -111dBm.
+ Weaker signals, or an environment with radio noise may
+ cause the data to not be received. The packet link uses
+ error detection and correction techniques which prevent
+ incorrect data from being reported.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ The age of the displayed data, in seconds since the last
+ successfully received telemetry packet. In normal operation
+ this will stay in the low single digits. If the number starts
+ counting up, then you are no longer receiving data over the radio
+ link from the flight computer.
+ </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 displays all of
+ the raw telemetry values in one place in a spreadsheet-like format.
+ </para>
+ <section>
+ <title>Launch Pad</title>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="launch-pad.png" width="5.5in"/>
+ </imageobject>
+ </mediaobject>
+ </informalfigure>
+ <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:
+ <variablelist>
+ <varlistentry>
+ <term>Battery Voltage</term>
+ <listitem>
+ <para>
+ This indicates whether the Li-Po battery powering the
+ flight computer has sufficient charge to last for
+ the duration of the flight. A value of more than
+ 3.8V is required for a 'GO' status.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Apogee Igniter Voltage</term>
+ <listitem>
+ <para>
+ 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 Li-Po battery voltage. A value greater than 3.2V is
+ required for a 'GO' status.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Main Igniter Voltage</term>
+ <listitem>
+ <para>
+ 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 Li-Po battery voltage. A value greater than 3.2V is
+ required for a 'GO' status.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>On-board Data Logging</term>
+ <listitem>
+ <para>
+ This indicates whether there is
+ space remaining on-board to store flight data for the
+ upcoming flight. If you've downloaded data, but failed
+ to erase flights, there may not be any space
+ left. Most of our flight computers can store multiple
+ flights, depending on the configured maximum flight log
+ size. TeleMini v1.0 stores only a single flight, so it
+ will need to be
+ downloaded and erased after each flight to capture
+ data. This only affects on-board flight logging; the
+ altimeter will still transmit telemetry and fire
+ ejection charges at the proper times even if the flight
+ data storage is full.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>GPS Locked</term>
+ <listitem>
+ <para>
+ For a TeleMetrum or TeleMega device, 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>
+ </varlistentry>
+ <varlistentry>
+ <term>GPS Ready</term>
+ <listitem>
+ <para>
+ For a TeleMetrum or TeleMega device, 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>
+ </varlistentry>
+ </variablelist>
+ </para>
+ <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>
+ </section>
+ <section>
+ <title>Ascent</title>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="ascent.png" width="5.5in"/>
+ </imageobject>
+ </mediaobject>
+ </informalfigure>
+ <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, acceleration and tilt are shown along
+ with the maximum 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>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="descent.png" width="5.5in"/>
+ </imageobject>
+ </mediaobject>
+ </informalfigure>
+ <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 vary based on the choice of recovery
+ components, but generally range from 15-30m/s on drogue and should
+ be below 10m/s when under the main parachute in a dual-deploy flight.
+ </para>
+ <para>
+ With GPS-equipped flight computers, you can locate the rocket in the
+ sky using 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. Ground Distance shows how far it is to a point
+ directly under the rocket and can help figure out where the
+ rocket is likely to land. 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. Note that some commercial
+ e-matches are designed to retain continuity even after being
+ fired, and will continue to show as green or return from red to
+ green after firing.
+ </para>
+ </section>
+ <section>
+ <title>Landed</title>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="landed.png" width="5.5in"/>
+ </imageobject>
+ </mediaobject>
+ </informalfigure>
+ <para>
+ Once the rocket is on the ground, attention switches to
+ recovery. While the radio signal is often 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 to walk or hitch a ride. Take the reported
+ latitude and longitude and enter them into your hand-held GPS
+ unit and have that compute a track to the landing location.
+ </para>
+ <para>
+ Our flight computers will continue to transmit RDF
+ tones after landing, allowing you to locate the rocket by
+ following the radio signal if necessary. You may need to get
+ away from the clutter of the flight line, or even get up on
+ a hill (or your neighbor's RV roof) to receive the RDF signal.
+ </para>
+ <para>
+ The maximum height, speed and acceleration reported
+ during the flight are displayed for your admiring observers.
+ The accuracy of these immediate values depends on the quality
+ of your radio link and how many packets were received.
+ Recovering the on-board data after flight may yield
+ more precise results.
+ </para>
+ <para>
+ To get more detailed information about the flight, you can
+ click on the 'Graph Flight' button which will bring up a
+ graph window for the current flight.
+ </para>
+ </section>
+ <section>
+ <title>Table</title>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="table.png" width="5.5in"/>
+ </imageobject>
+ </mediaobject>
+ </informalfigure>
+ <para>
+ The table view shows all of the data available from the
+ flight computer. Probably the most useful data on
+ this tab is the detailed GPS information, which includes
+ horizontal dilution of precision information, and
+ information about the signal being received from the satellites.
+ </para>
+ </section>
+ <section>
+ <title>Site Map</title>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="site-map.png" width="5.5in"/>
+ </imageobject>
+ </mediaobject>
+ </informalfigure>
+ <para>
+ When the TeleMetrum has 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 color: 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 default 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 centered while data is being received.
+ </para>
+ <para>
+ You can adjust the style of map and the zoom level with
+ buttons on the right side of the map window. You can draw a
+ line on the map by moving the mouse over the map with a
+ button other than the left one pressed, or by pressing the
+ left button while also holding down the shift key. The
+ length of the line in real-world units will be shown at the
+ start of the line.
+ </para>
+ <para>
+ Images are fetched automatically via the Google Maps Static API,
+ and cached on disk for reuse. If map images cannot be downloaded,
+ the rocket's path will be traced on a dark gray background
+ instead.
+ </para>
+ <para>
+ You can pre-load images for your favorite launch sites
+ before you leave home; check out the 'Preload Maps' section below.
+ </para>
+ </section>
+ <section>
+ <title>Ignitor</title>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="ignitor.png" width="5.5in"/>
+ </imageobject>
+ </mediaobject>
+ </informalfigure>
+ <para>
+ TeleMega includes four additional programmable pyro
+ channels. The Ignitor tab shows whether each of them has
+ continuity. If an ignitor has a low resistance, then the
+ voltage measured here will be close to the pyro battery
+ voltage. A value greater than 3.2V is required for a 'GO'
+ status.
+ </para>
+ </section>
+ </section>
+ <section>
+ <title>Save Flight Data</title>
+ <para>
+ The altimeter records flight data to its internal flash memory.
+ TeleMetrum 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 flight computers and TeleDongle devices. If you select a
+ flight computer, the flight data will be downloaded from that
+ device directly. If you select a TeleDongle device, flight data
+ will be downloaded from a flight computer over radio link via the
+ specified TeleDongle. See the chapter on Controlling An Altimeter
+ Over The Radio Link for more information.
+ </para>
+ <para>
+ After the device has been selected, a dialog showing the
+ flight data saved in the device will be shown allowing you to
+ select which flights to download and which to delete. With
+ version 0.9 or newer firmware, you must erase flights in order
+ for the space they consume to be reused by another
+ flight. This prevents accidentally losing flight data
+ if you neglect to download data before flying again. Note that
+ if there is no more space available in the device, then no
+ data will be recorded during the next flight.
+ </para>
+ <para>
+ The file name for each flight log is computed automatically
+ from the recorded flight date, altimeter 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 altimeter
+ 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
+ flash memory.
+ </para>
+ <para>
+ Note that telemetry files will generally produce poor graphs
+ due to the lower sampling rate and missed telemetry packets.
+ Use saved flight data in .eeprom files for graphing where possible.
+ </para>
+ <para>
+ Once a flight record is selected, a window with multiple tabs is
+ opened.
+ </para>
+ <section>
+ <title>Flight Graph</title>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="graph.png" width="6in" scalefit="1"/>
+ </imageobject>
+ </mediaobject>
+ </informalfigure>
+ <para>
+ By default, the graph contains acceleration (blue),
+ velocity (green) and altitude (red).
+ </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 pop-up menu to be displayed, giving
+ you the option save or print the plot.
+ </para>
+ </section>
+ <section>
+ <title>Configure Graph</title>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="graph-configure.png" width="6in" scalefit="1"/>
+ </imageobject>
+ </mediaobject>
+ </informalfigure>
+ <para>
+ This selects which graph elements to show, and, at the
+ very bottom, lets you switch between metric and
+ imperial units
+ </para>
+ </section>
+ <section>
+ <title>Flight Statistics</title>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="graph-stats.png" width="6in" scalefit="1"/>
+ </imageobject>
+ </mediaobject>
+ </informalfigure>
+ <para>
+ Shows overall data computed from the flight.
+ </para>
+ </section>
+ <section>
+ <title>Map</title>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="graph-map.png" width="6in" scalefit="1"/>
+ </imageobject>
+ </mediaobject>
+ </informalfigure>
+ <para>
+ Shows a satellite image of the flight area overlaid
+ with the path of the flight. The red concentric
+ circles mark the launch pad, the black concentric
+ circles mark the landing location.
+ </para>
+ </section>
+ </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, which can be either a .eeprom or .telem.
+ The .eeprom files contain higher resolution and more continuous data,
+ while .telem files contain receiver signal strength information.
+ 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 altimeter, then
+ there is a single header line which labels all of the
+ fields. All of these lines start with a '#' character which
+ many 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 Google Earth to provide an overlay
+ within that application. With this, you can use Google Earth to
+ see the whole flight path in 3D.
+ </para>
+ </section>
+ </section>
+ <section>
+ <title>Configure Altimeter</title>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="configure-altimeter.png" width="3.6in" scalefit="1"/>
+ </imageobject>
+ </mediaobject>
+ </informalfigure>
+ <para>
+ Select this button and then select either an altimeter or
+ TeleDongle Device from the list provided. Selecting a TeleDongle
+ device will use the radio link to configure a remote altimeter.
+ </para>
+ <para>
+ The first few lines of the dialog provide information about the
+ connected 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>
+ <variablelist>
+ <varlistentry>
+ <term>Save</term>
+ <listitem>
+ <para>
+ This writes any changes to the
+ configuration parameter block in flash memory. If you don't
+ press this button, any changes you make will be lost.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Reset</term>
+ <listitem>
+ <para>
+ This resets the dialog to the most recently saved values,
+ erasing any changes you have made.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Reboot</term>
+ <listitem>
+ <para>
+ This reboots the device. Use this to
+ switch from idle to pad mode by rebooting once the rocket is
+ oriented for flight, or to confirm changes you think you saved
+ are really saved.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Close</term>
+ <listitem>
+ <para>
+ This closes the dialog. Any unsaved changes will be
+ lost.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <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 over pressurize the apogee deployment
+ bay and cause a structural failure of the air-frame. 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>Apogee Lockoug</title>
+ <para>
+ Apogee lockout is the number of seconds after boost where
+ the flight computer will not fire the apogee charge, even if
+ the rocket appears to be at apogee. This is often called
+ 'Mach Delay', as it is intended to prevent a flight computer
+ from unintentionally firing apogee charges due to the pressure
+ spike that occurrs across a mach transition. Altus Metrum
+ flight computers include a Kalman filter which is not fooled
+ by this sharp pressure increase, and so this setting should
+ be left at the default value of zero to disable it.
+ </para>
+ </section>
+ <section>
+ <title>Frequency</title>
+ <para>
+ This configures which of the frequencies to use for both
+ telemetry and packet command mode. Note that if you set this
+ value via packet command mode, the TeleDongle frequency will
+ also be automatically reconfigured to match so that
+ communication will continue afterwards.
+ </para>
+ </section>
+ <section>
+ <title>RF 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. If you need to you can adjust the calibration
+ by changing this value. Do not do this without understanding what
+ the value means, read the appendix on calibration and/or the source
+ code for more information. To change a TeleDongle's calibration,
+ you must reprogram the unit completely.
+ </para>
+ </section>
+ <section>
+ <title>Telemetry/RDF/APRS Enable</title>
+ <para>
+ Enables the radio for transmission during flight. When
+ disabled, the radio will not transmit anything during flight
+ at all.
+ </para>
+ </section>
+ <section>
+ <title>Telemetry baud rate</title>
+ <para>
+ This sets the modulation bit rate for data transmission for
+ both telemetry and packet link mode. Lower bit
+ rates will increase range while reducing the amount of data
+ that can be sent and increasing battery consumption. All
+ telemetry is done using a rate 1/2 constraint 4 convolution
+ code, so the actual data transmission rate is 1/2 of the
+ modulation bit rate specified here.
+ </para>
+ </section>
+ <section>
+ <title>APRS Interval</title>
+ <para>
+ How often to transmit GPS information via APRS (in
+ seconds). When set to zero, APRS transmission is
+ disabled. This option is available on TeleMetrum v2 and
+ TeleMega boards. TeleMetrum v1 boards cannot transmit APRS
+ packets. Note that a single APRS packet takes nearly a full
+ second to transmit, so enabling this option will prevent
+ sending any other telemetry during that time.
+ </para>
+ </section>
+ <section>
+ <title>APRS SSID</title>
+ <para>
+ Which SSID to report in APRS packets. By default, this is
+ set to the last digit of the serial number, but can be
+ configured to any value from 0 to 9.
+ </para>
+ </section>
+ <section>
+ <title>Callsign</title>
+ <para>
+ This sets the call sign included in each telemetry packet. Set this
+ as needed to conform to your local radio regulations.
+ </para>
+ </section>
+ <section>
+ <title>Maximum Flight Log Size</title>
+ <para>
+ This sets the space (in kilobytes) allocated for each flight
+ log. The available space will be divided into chunks of this
+ size. A smaller value will allow more flights to be stored,
+ a larger value will record data from longer flights.
+ </para>
+ </section>
+ <section>
+ <title>Ignitor Firing Mode</title>
+ <para>
+ This configuration parameter allows the two standard ignitor
+ channels (Apogee and Main) to be used in different
+ configurations.
+ </para>
+ <variablelist>
+ <varlistentry>
+ <term>Dual Deploy</term>
+ <listitem>
+ <para>
+ This is the usual mode of operation; the
+ 'apogee' channel is fired at apogee and the 'main'
+ channel at the height above ground specified by the
+ 'Main Deploy Altitude' during descent.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Redundant Apogee</term>
+ <listitem>
+ <para>
+ This fires both channels at
+ apogee, the 'apogee' channel first followed after a two second
+ delay by the 'main' channel.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Redundant Main</term>
+ <listitem>
+ <para>
+ This fires both channels at the
+ height above ground specified by the Main Deploy
+ Altitude setting during descent. The 'apogee'
+ channel is fired first, followed after a two second
+ delay by the 'main' channel.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </section>
+ <section>
+ <title>Pad Orientation</title>
+ <para>
+ Because they include accelerometers, TeleMetrum,
+ TeleMega and EasyMega are sensitive to the orientation of the board. By
+ default, they expect the antenna end to point forward. This
+ parameter allows that default to be changed, permitting the
+ board to be mounted with the antenna pointing aft instead.
+ </para>
+ <variablelist>
+ <varlistentry>
+ <term>Antenna Up</term>
+ <listitem>
+ <para>
+ In this mode, the antenna end of the
+ flight computer must point forward, in line with the
+ expected flight path.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Antenna Down</term>
+ <listitem>
+ <para>
+ In this mode, the antenna end of the
+ flight computer must point aft, in line with the
+ expected flight path.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </section>
+ <section>
+ <title>Beeper Frequency</title>
+ <para>
+ The beeper on all Altus Metrum flight computers works best
+ at 4000Hz, however if you have more than one flight computer
+ in a single airframe, having all of them sound at the same
+ frequency can be confusing. This parameter lets you adjust
+ the base beeper frequency value.
+ </para>
+ </section>
+ <section>
+ <title>Configure Pyro Channels</title>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="configure-pyro.png" width="6in" scalefit="1"/>
+ </imageobject>
+ </mediaobject>
+ </informalfigure>
+ <para>
+ This opens a separate window to configure the additional
+ pyro channels available on TeleMega and EasyMega. One column is
+ presented for each channel. Each row represents a single
+ parameter, if enabled the parameter must meet the specified
+ test for the pyro channel to be fired. See the Pyro Channels
+ section in the System Operation chapter above for a
+ description of these parameters.
+ </para>
+ <para>
+ Select conditions and set the related value; the pyro
+ channel will be activated when <emphasis>all</emphasis> of the
+ conditions are met. Each pyro channel has a separate set of
+ configuration values, so you can use different values for
+ the same condition with different channels.
+ </para>
+ <para>
+ At the bottom of the window, the 'Pyro Firing Time'
+ configuration sets the length of time (in seconds) which
+ each of these pyro channels will fire for.
+ </para>
+ <para>
+ Once you have selected the appropriate configuration for all
+ of the necessary pyro channels, you can save the pyro
+ configuration along with the rest of the flight computer
+ configuration by pressing the 'Save' button in the main
+ Configure Flight Computer window.
+ </para>
+ </section>
+ </section>
+ <section>
+ <title>Configure AltosUI</title>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="configure-altosui.png" width="2.4in" scalefit="1"/>
+ </imageobject>
+ </mediaobject>
+ </informalfigure>
+ <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 announcements 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>
+ <variablelist>
+ <varlistentry>
+ <term>Enable</term>
+ <listitem>
+ <para>Turns all voice announcements on and off</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Test Voice</term>
+ <listitem>
+ <para>
+ Plays a short message allowing you to verify
+ that the audio system is working and the volume settings
+ are reasonable
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </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.