+ <title>Altus Metrum Hardware</title>
+ <section>
+ <title>General Usage Instructions</title>
+ <para>
+ Here are general instructions for hooking up an Altus Metrum
+ flight computer. Instructions specific to each model will be
+ found in the section devoted to that model below.
+ </para>
+ <para>
+ To prevent electrical interference from affecting the
+ operation of the flight computer, it's important to always
+ twist pairs of wires connected to the board. Twist the switch
+ leads, the pyro leads and the battery leads. This reduces
+ interference through a mechanism called common mode rejection.
+ </para>
+ <section>
+ <title>Hooking Up Lithium Polymer Batteries</title>
+ <para>
+ All Altus Metrum flight computers have a two pin JST PH
+ series connector to connect up a single-cell Lithium Polymer
+ cell (3.7V nominal). You can purchase matching batteries
+ from the Altus Metrum store, or other vendors, or you can
+ make your own. Pin 1 of the connector is positive, pin 2 is
+ negative. Spark Fun sells a cable with the connector
+ attached, which they call a <ulink
+ url="https://www.sparkfun.com/products/9914">JST Jumper 2
+ Wire Assembly</ulink>.
+ </para>
+ <para>
+ Many RC vendors also sell lithium polymer batteries with
+ this same connector. All that we have found use the opposite
+ polarity, and if you use them that way, you will damage or
+ destroy the flight computer.
+ </para>
+ </section>
+ <section>
+ <title>Hooking Up Pyro Charges</title>
+ <para>
+ Altus Metrum flight computers always have two screws for
+ each pyro charge. This means you shouldn't need to put two
+ wires into a screw terminal or connect leads from pyro
+ charges together externally.
+ </para>
+ <para>
+ On the flight computer, one lead from each charge is hooked
+ to the positive battery terminal through the power switch.
+ The other lead is connected through the pyro circuit, which
+ is connected to the negative battery terminal when the pyro
+ circuit is fired.
+ </para>
+ </section>
+ <section>
+ <title>Hooking Up a Power Switch</title>
+ <para>
+ Altus Metrum flight computers need an external power switch
+ to turn them on. This disconnects both the computer and the
+ pyro charges from the battery, preventing the charges from
+ firing when in the Off position. The switch is in-line with
+ the positive battery terminal.
+ </para>
+ <section>
+ <title>Using an External Active Switch Circuit</title>
+ <para>
+ You can use an active switch circuit, such as the
+ Featherweight Magnetic Switch, with any Altus Metrum
+ flight computer. These require three connections, one to
+ the battery, one to the positive power input on the flight
+ computer and one to ground. Find instructions on how to
+ hook these up for each flight computer below. The follow
+ the instructions that come with your active switch to
+ connect it up.
+ </para>
+ </section>
+ </section>
+ <section>
+ <title>Using a Separate Pyro Battery</title>
+ <para>
+ As mentioned above in the section on hooking up pyro
+ charges, one lead for each of the pyro charges is connected
+ through the power switch directly to the positive battery
+ terminal. The other lead is connected to the pyro circuit,
+ which connects it to the negative battery terminal when the
+ pyro circuit is fired. The pyro circuit on all of the flight
+ computers is designed to handle up to 16V.
+ </para>
+ <para>
+ To use a separate pyro battery, connect the negative pyro
+ battery terminal to the flight computer ground terminal,
+ the positive battery terminal to the igniter and the other
+ igniter lead to the negative pyro terminal on the flight
+ computer. When the pyro channel fires, it will complete the
+ circuit between the negative pyro terminal and the ground
+ terminal, firing the igniter. Specific instructions on how
+ to hook this up will be found in each section below.
+ </para>
+ </section>
+ <section>
+ <title>Using a Different Kind of Battery</title>
+ <para>
+ EasyMini and TeleMini v2 are designed to use either a
+ lithium polymer battery or any other battery producing
+ between 4 and 12 volts, such as a rectangular 9V
+ battery. TeleMega and TeleMetrum are not designed for this,
+ and must only be powered by a lithium polymer battery. Find
+ instructions on how to use other batteries in the EasyMini
+ and TeleMini sections below.
+ </para>
+ </section>
+ </section>
+ <section>
+ <title>Specifications</title>
+ <para>
+ Here's the full set of Altus Metrum products, both in
+ production and retired.
+ </para>
+ <table frame='all'>
+ <title>Altus Metrum Electronics</title>
+ <?dbfo keep-together="always"?>
+ <tgroup cols='8' align='center' colsep='1' rowsep='1'>
+ <colspec align='center' colwidth='*' colname='Device'/>
+ <colspec align='center' colwidth='*' colname='Barometer'/>
+ <colspec align='center' colwidth='*' colname='Z-axis accelerometer'/>
+ <colspec align='center' colwidth='*' colname='GPS'/>
+ <colspec align='center' colwidth='*' colname='3D sensors'/>
+ <colspec align='center' colwidth='*' colname='Storage'/>
+ <colspec align='center' colwidth='*' colname='RF'/>
+ <colspec align='center' colwidth='*' colname='Battery'/>
+ <thead>
+ <row>
+ <entry align='center'>Device</entry>
+ <entry align='center'>Barometer</entry>
+ <entry align='center'>Z-axis accelerometer</entry>
+ <entry align='center'>GPS</entry>
+ <entry align='center'>3D sensors</entry>
+ <entry align='center'>Storage</entry>
+ <entry align='center'>RF Output</entry>
+ <entry align='center'>Battery</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>TeleMetrum v1.0</entry>
+ <entry><para>MP3H6115 10km (33k')</para></entry>
+ <entry><para>MMA2202 50g</para></entry>
+ <entry>SkyTraq</entry>
+ <entry>-</entry>
+ <entry>1MB</entry>
+ <entry>10mW</entry>
+ <entry>3.7V</entry>
+ </row>
+ <row>
+ <entry>TeleMetrum v1.1</entry>
+ <entry><para>MP3H6115 10km (33k')</para></entry>
+ <entry><para>MMA2202 50g</para></entry>
+ <entry>SkyTraq</entry>
+ <entry>-</entry>
+ <entry>2MB</entry>
+ <entry>10mW</entry>
+ <entry>3.7V</entry>
+ </row>
+ <row>
+ <entry>TeleMetrum v1.2</entry>
+ <entry><para>MP3H6115 10km (33k')</para></entry>
+ <entry><para>ADXL78 70g</para></entry>
+ <entry>SkyTraq</entry>
+ <entry>-</entry>
+ <entry>2MB</entry>
+ <entry>10mW</entry>
+ <entry>3.7V</entry>
+ </row>
+ <row>
+ <entry>TeleMetrum v2.0</entry>
+ <entry><para>MS5607 30km (100k')</para></entry>
+ <entry><para>MMA6555 102g</para></entry>
+ <entry>uBlox Max-7Q</entry>
+ <entry>-</entry>
+ <entry>8MB</entry>
+ <entry>40mW</entry>
+ <entry>3.7V</entry>
+ </row>
+ <row>
+ <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
+ <entry><para>MP3H6115 10km (33k')</para></entry>
+ <entry>-</entry>
+ <entry>-</entry>
+ <entry>-</entry>
+ <entry>5kB</entry>
+ <entry>10mW</entry>
+ <entry>3.7V</entry>
+ </row>
+ <row>
+ <entry>TeleMini <?linebreak?>v2.0</entry>
+ <entry><para>MS5607 30km (100k')</para></entry>
+ <entry>-</entry>
+ <entry>-</entry>
+ <entry>-</entry>
+ <entry>1MB</entry>
+ <entry>10mW</entry>
+ <entry>3.7-12V</entry>
+ </row>
+ <row>
+ <entry>EasyMini <?linebreak?>v1.0</entry>
+ <entry><para>MS5607 30km (100k')</para></entry>
+ <entry>-</entry>
+ <entry>-</entry>
+ <entry>-</entry>
+ <entry>1MB</entry>
+ <entry>-</entry>
+ <entry>3.7-12V</entry>
+ </row>
+ <row>
+ <entry>TeleMega <?linebreak?>v1.0</entry>
+ <entry><para>MS5607 30km (100k')</para></entry>
+ <entry><para>MMA6555 102g</para></entry>
+ <entry>uBlox Max-7Q</entry>
+ <entry><para>MPU6000 HMC5883</para></entry>
+ <entry>8MB</entry>
+ <entry>40mW</entry>
+ <entry>3.7V</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ <table frame='all'>
+ <title>Altus Metrum Boards</title>
+ <?dbfo keep-together="always"?>
+ <tgroup cols='6' align='center' colsep='1' rowsep='1'>
+ <colspec align='center' colwidth='*' colname='Device'/>
+ <colspec align='center' colwidth='*' colname='Connectors'/>
+ <colspec align='center' colwidth='*' colname='Screw Terminals'/>
+ <colspec align='center' colwidth='*' colname='Width'/>
+ <colspec align='center' colwidth='*' colname='Length'/>
+ <colspec align='center' colwidth='*' colname='Tube Size'/>
+ <thead>
+ <row>
+ <entry align='center'>Device</entry>
+ <entry align='center'>Connectors</entry>
+ <entry align='center'>Screw Terminals</entry>
+ <entry align='center'>Width</entry>
+ <entry align='center'>Length</entry>
+ <entry align='center'>Tube Size</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>TeleMetrum</entry>
+ <entry><para>
+ Antenna<?linebreak?>
+ Debug<?linebreak?>
+ Companion<?linebreak?>
+ USB<?linebreak?>
+ Battery
+ </para></entry>
+ <entry><para>Apogee pyro <?linebreak?>Main pyro <?linebreak?>Switch</para></entry>
+ <entry>1 inch (2.54cm)</entry>
+ <entry>2 ¾ inch (6.99cm)</entry>
+ <entry>29mm coupler</entry>
+ </row>
+ <row>
+ <entry><para>TeleMini <?linebreak?>v1.0</para></entry>
+ <entry><para>
+ Antenna<?linebreak?>
+ Debug<?linebreak?>
+ Battery
+ </para></entry>
+ <entry><para>
+ Apogee pyro <?linebreak?>
+ Main pyro
+ </para></entry>
+ <entry>½ inch (1.27cm)</entry>
+ <entry>1½ inch (3.81cm)</entry>
+ <entry>18mm coupler</entry>
+ </row>
+ <row>
+ <entry>TeleMini <?linebreak?>v2.0</entry>
+ <entry><para>
+ Antenna<?linebreak?>
+ Debug<?linebreak?>
+ USB<?linebreak?>
+ Battery
+ </para></entry>
+ <entry><para>
+ Apogee pyro <?linebreak?>
+ Main pyro <?linebreak?>
+ Battery <?linebreak?>
+ Switch
+ </para></entry>
+ <entry>0.8 inch (2.03cm)</entry>
+ <entry>1½ inch (3.81cm)</entry>
+ <entry>24mm coupler</entry>
+ </row>
+ <row>
+ <entry>EasyMini</entry>
+ <entry><para>
+ Debug<?linebreak?>
+ USB<?linebreak?>
+ Battery
+ </para></entry>
+ <entry><para>
+ Apogee pyro <?linebreak?>
+ Main pyro <?linebreak?>
+ Battery <?linebreak?>
+ Switch
+ </para></entry>
+ <entry>0.8 inch (2.03cm)</entry>
+ <entry>1½ inch (3.81cm)</entry>
+ <entry>24mm coupler</entry>
+ </row>
+ <row>
+ <entry>TeleMega</entry>
+ <entry><para>
+ Antenna<?linebreak?>
+ Debug<?linebreak?>
+ Companion<?linebreak?>
+ USB<?linebreak?>
+ Battery
+ </para></entry>
+ <entry><para>
+ Apogee pyro <?linebreak?>
+ Main pyro<?linebreak?>
+ Pyro A-D<?linebreak?>
+ Switch<?linebreak?>
+ Pyro battery
+ </para></entry>
+ <entry>1¼ inch (3.18cm)</entry>
+ <entry>3¼ inch (8.26cm)</entry>
+ <entry>38mm coupler</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </section>
+ <section>
+ <title>TeleMetrum</title>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="telemetrum-v1.1-thside.jpg" width="5.5in" scalefit="1"/>
+ </imageobject>
+ </mediaobject>
+ </informalfigure>
+ <para>
+ TeleMetrum is a 1 inch by 2¾ inch circuit board. It was designed to
+ fit inside coupler for 29mm air-frame tubing, but using it in a tube that
+ small in diameter may require some creativity in mounting and wiring
+ to succeed! The presence of an accelerometer means TeleMetrum should
+ be aligned along the flight axis of the airframe, and by default the ¼
+ wave UHF wire antenna should be on the nose-cone end of the board. The
+ antenna wire 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, meaning an ideal “simple” avionics
+ bay for TeleMetrum should have at least 10 inches of interior length.
+ </para>
+ <section>
+ <title>TeleMetrum Screw Terminals</title>
+ <para>
+ TeleMetrum has six screw terminals on the end of the board
+ opposite the telemetry antenna. Two are for the power
+ switch, and two each for the apogee and main igniter
+ circuits. Using the picture above and starting from the top,
+ the terminals are as follows:
+ </para>
+ <table frame='all'>
+ <title>TeleMetrum 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>1</entry>
+ <entry>Switch Output</entry>
+ <entry>Switch connection to flight computer</entry>
+ </row>
+ <row>
+ <entry>2</entry>
+ <entry>Switch Input</entry>
+ <entry>Switch connection to positive battery terminal</entry>
+ </row>
+ <row>
+ <entry>3</entry>
+ <entry>Main +</entry>
+ <entry>Main pyro channel common connection to battery +</entry>
+ </row>
+ <row>
+ <entry>4</entry>
+ <entry>Main -</entry>
+ <entry>Main pyro channel connection to pyro circuit</entry>
+ </row>
+ <row>
+ <entry>5</entry>
+ <entry>Apogee +</entry>
+ <entry>Apogee pyro channel common connection to battery +</entry>
+ </row>
+ <row>
+ <entry>6</entry>
+ <entry>Apogee -</entry>
+ <entry>Apogee pyro channel connection to pyro circuit</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </section>
+ <section>
+ <title>Using a Separate Pyro Battery with TeleMetrum</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 battery terminal to the TeleMetrum
+ ground, insert a small piece of wire, 24 to 28 gauge
+ stranded, into the GND hole just above the screw terminal
+ strip and solder it in place.
+ </para>
+ <para>
+ Connecting the positive battery terminal to the pyro
+ charges must be done separate from TeleMetrum, 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 (terminal 4 for the
+ Main charge, terminal 6 for the Apogee charge).
+ </para>
+ </section>
+ <section>
+ <title>Using an Active Switch with TeleMetrum</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 screw terminal
+ 2, the positive flight computer input is on terminal 1. To
+ hook a lead to ground, solder a piece of wire, 24 to 28
+ gauge stranded, to the GND hole just above terminal 1.
+ </para>
+ </section>
+ </section>
+ <section>
+ <title>TeleMini v1.0</title>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="telemini-v1-top.jpg" width="5.5in" scalefit="1"/>
+ </imageobject>
+ </mediaobject>
+ </informalfigure>
+ <para>
+ TeleMini v1.0 is ½ inches by 1½ inches. It was
+ designed to fit inside an 18mm air-frame tube, but using it in
+ a tube that small in diameter may require some creativity in
+ mounting and wiring to succeed! Since there is no
+ accelerometer, TeleMini can be mounted in any convenient
+ orientation. The default ¼ wave UHF wire antenna attached to
+ the center of one end of the board is about 7 inches long. Two
+ wires for the power switch are connected to holes in the
+ middle of the board. Screw terminals for the e-matches for
+ apogee and main ejection charges depart from the other end of
+ the board, meaning an ideal “simple” avionics bay for TeleMini
+ should have at least 9 inches of interior length.
+ </para>
+ <section>
+ <title>TeleMini v1.0 Screw Terminals</title>
+ <para>
+ TeleMini v1.0 has four screw terminals on the end of the
+ board opposite the telemetry antenna. Two are for the apogee
+ and two are for main igniter circuits. There are also wires
+ soldered to the board for the power switch. Using the
+ picture above and starting from the top for the terminals
+ and from the left for the power switch wires, the
+ connections are as follows:
+ </para>
+ <table frame='all'>
+ <title>TeleMini v1.0 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>1</entry>
+ <entry>Apogee -</entry>
+ <entry>Apogee pyro channel connection to pyro circuit</entry>
+ </row>
+ <row>
+ <entry>2</entry>
+ <entry>Apogee +</entry>
+ <entry>Apogee pyro channel common connection to battery +</entry>
+ </row>
+ <row>
+ <entry>3</entry>
+ <entry>Main -</entry>
+ <entry>Main pyro channel connection to pyro circuit</entry>
+ </row>
+ <row>
+ <entry>4</entry>
+ <entry>Main +</entry>
+ <entry>Main pyro channel common connection to battery +</entry>
+ </row>
+ <row>
+ <entry>Left</entry>
+ <entry>Switch Output</entry>
+ <entry>Switch connection to flight computer</entry>
+ </row>
+ <row>
+ <entry>Right</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 TeleMini v1.0</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. Because
+ there is no solid ground connection to use on TeleMini, this
+ is not recommended.
+ </para>
+ <para>
+ The only available ground connection on TeleMini v1.0 are
+ the two mounting holes next to the telemetry
+ antenna. Somehow connect a small piece of wire to one of
+ those holes and hook it to the negative pyro battery terminal.
+ </para>
+ <para>
+ Connecting the positive battery terminal to the pyro
+ charges must be done separate from TeleMini v1.0, 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 (terminal 3 for the
+ Main charge, terminal 1 for the Apogee charge).
+ </para>
+ </section>
+ <section>
+ <title>Using an Active Switch with TeleMini v1.0</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. Again,
+ because TeleMini doesn't have any good ground connection,
+ this is not recommended.
+ </para>
+ <para>
+ The positive battery terminal is available on the Right
+ power switch wire, the positive flight computer input is on
+ the left power switch wire. Hook a lead to either of the
+ mounting holes for a ground connection.
+ </para>
+ </section>
+ </section>
+ <section>
+ <title>TeleMini v2.0</title>
+ <informalfigure>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="telemini-v2-top.jpg" width="5.5in" scalefit="1"/>
+ </imageobject>
+ </mediaobject>
+ </informalfigure>
+ <para>
+ TeleMini v2.0 is 0.8 inches by 1½ inches. It adds more
+ on-board data logging memory, a built-in USB connector and
+ screw terminals for the battery and power switch. The larger
+ board fits in a 24mm coupler. There's also a battery connector
+ for a LiPo battery if you want to use one of those.
+ </para>
+ <section>
+ <title>TeleMini v2.0 Screw Terminals</title>
+ <para>
+ TeleMini v2.0 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>TeleMini v2.0 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 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>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>
+ </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 and TeleMega
+ 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>