- <title>Hardware Overview</title>
- <para>
- TeleMetrum is a 1 inch by 2.75 inch circuit board. It was designed to
- fit inside coupler for 29mm 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 1/4
- 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>
- <para>
- TeleMini is a 0.5 inch by 1.5 inch circuit board. 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 1/4
- wave UHF wire antenna attached to the center of one end of
- the board is about 7 inches long, and wiring for a power switch and
- the e-matches for apogee and main ejection charges depart from the
- other end of the board, meaning an ideal "simple" avionics
- bay for TeleMini should have at least 9 inches of interior length.
- </para>
- <para>
- A typical TeleMetrum or TeleMini installation involves attaching
- only a suitable Lithium Polymer battery, a single pole switch for
- power on/off, and two pairs of wires connecting e-matches for the
- apogee and main ejection charges.
- </para>
- <para>
- By default, we use the unregulated output of the Li-Po 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>
- TeleMetrum also uses the screw terminal block for the power
- switch leads. On TeleMini, 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
- order an altimeter with an SMA connector for the UHF antenna
- connection, and, on TeleMetrum, you can unplug the integrated GPS
- antenna and select an appropriate off-board GPS antenna with
- cable terminating in a U.FL connector.
- </para>
+ <title>Altus Metrum Hardware</title>
+ <section>
+ <title>Overview</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>
+ <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>
+ <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 aiframe</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>
+ <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>
+ <section>
+ <title>TeleMini</title>
+ <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>
+ <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>
+ <section>
+ <title>EasyMini</title>
+ <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, so you can swap an EasyMini
+ with a TeleMini.
+ </para>
+ </section>
+ <section>
+ <title>TeleMega</title>
+ <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>
+ <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>
+ <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
+ order an altimeter with an SMA connector for the UHF antenna
+ connection, 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>