353 lines
11 KiB
PHP
353 lines
11 KiB
PHP
== Using Altus Metrum Hardware
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Here are general instructions for hooking up an Altus Metrum
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flight computer. Instructions specific to each model will be
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found in the section devoted to that model below.
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=== Wiring and Electrical Interference
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To prevent electrical interference from affecting the
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operation of the flight computer, it's important to always
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twist pairs of wires connected to the board. Twist the switch
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leads, the pyro leads and the battery leads. This reduces
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interference through a mechanism called common mode rejection.
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=== Hooking Up Lithium Polymer Batteries
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All Altus Metrum flight computers have a two pin JST PH
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series connector to connect up a single-cell Lithium Polymer
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cell (3.7V nominal). You can purchase matching batteries
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from the Altus Metrum store, or other vendors, or you can
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make your own. Pin 1 of the connector is positive, pin 2 is
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negative. Spark Fun sells a cable with the connector
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attached, which they call a
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link:https://www.sparkfun.com/products/9914[JST Jumper 2 Wire Assembly]
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[WARNING]
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Many RC vendors also sell lithium polymer batteries with
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this same connector. All that we have found use the opposite
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polarity, and if you use them that way, you will damage or
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destroy the flight computer.
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=== Hooking Up Pyro Charges
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Altus Metrum flight computers always have two screws for
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each pyro charge. This means you shouldn't need to put two
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wires into a screw terminal or connect leads from pyro
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charges together externally.
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On the flight computer, one lead from each charge is hooked
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to the positive battery terminal through the power switch.
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The other lead is connected through the pyro circuit, which
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is connected to the negative battery terminal when the pyro
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circuit is fired.
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=== Hooking Up a Power Switch
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Altus Metrum flight computers need an external power switch
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to turn them on. This disconnects both the computer and the
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pyro charges from the battery, preventing the charges from
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firing when in the Off position. The switch is in-line with
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the positive battery terminal.
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=== Understanding Beeps
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Altus Metrum flight computers include a beeper to
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provide information about the state of the system.
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ifdef::telemini[]
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TeleMini doesn't have room for a beeper, so instead it
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uses an LED, which works the same, except for every
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beep is replaced with the flash of the LED.
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endif::telemini[]
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Here's a short summary of all of the modes and the
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beeping
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ifdef::telemini[(or flashing, in the case of TeleMini v1)]
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that accompanies each mode. In the description of the
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beeping pattern, “dit” means a short beep while "dah"
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means a long beep (three times as long). “Brap” means
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a long dissonant tone.
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.AltOS Modes
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[options="border",cols="1,1,2,2"]
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|Mode Name
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|Abbreviation
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|Beeps
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|Description
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|Startup
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|S
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|battery voltage in decivolts
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|Calibrating sensors, detecting orientation.
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|Idle
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|I
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|dit dit
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|Ready to accept commands over USB
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ifdef::radio[or radio link.]
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|Pad
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|P
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|dit dah dah dit
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|Waiting for launch. Not listening for commands.
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|Boost
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|B
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|dah dit dit dit
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|Accelerating upwards.
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|Fast
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|F
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|dit dit dah dit
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|Decelerating, but moving faster than 200m/s.
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|Coast
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|C
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|dah dit dah dit
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|Decelerating, moving slower than 200m/s
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|Drogue
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|D
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|dah dit dit
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|Descending after apogee. Above main height.
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|Main
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|M
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|dah dah
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|Descending. Below main height.
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|Landed
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|L
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|dit dah dit dit
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|Stable altitude for at least ten seconds.
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|Sensor error
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|X
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|dah dit dit dah
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|Error detected during sensor calibration.
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|====
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Here's a summary of all of the Pad and Idle mode
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indications. In Idle mode, you'll hear one of these
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just once after the two short dits indicating idle
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mode. In Pad mode, after the dit dah dah dit
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indicating Pad mode, you'll hear these once every five
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seconds.
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.Pad/Idle Indications
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[options="header",cols="1,1,3"]
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|Name |Beeps |Description
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|Neither
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|brap
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|No continuity detected on either apogee or main igniters.
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|Apogee
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|dit
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|Continuity detected only on apogee igniter.
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|Main
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|dit dit
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|Continuity detected only on main igniter.
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|Both
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|dit dit dit
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|Continuity detected on both igniters.
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|Storage Full
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|warble
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|On-board data logging storage is full. This will
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not prevent the flight computer from safely
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controlling the flight or transmitting telemetry
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signals, but no record of the flight will be
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stored in on-board flash.
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ifdef::easymega,telemega,easytimer[]
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|Additional Igniters
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|four very short beeps
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|Continuity indication for the additional pyro
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channels on TeleMega, EasyMega and EasyTimer. One high tone for
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no continuity, one low tone for continuity. On TeleMega and EasyMegay, these are
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produced after the continuity indicators for the two
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primary igniter channels.
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endif::easymega,telemega,easytimer[]
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ifdef::radio[]
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For devices with a radio transmitter, in addition to
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the digital and APRS telemetry signals, you can also
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receive audio tones with a standard amateur
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70cm FM receiver. While on the pad, you will hear
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igniter status once every five seconds.
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.Pad Radio Indications
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[options="header",cols="1,1,3"]
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|Name |Beeps |Description
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|Neither
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|½ second tone
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|No continuity detected on either apogee or main igniters.
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|Apogee
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|dit
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|Continuity detected only on apogee igniter.
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|Main
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|dit dit
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|Continuity detected only on main igniter.
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|Both
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|dit dit dit
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|Continuity detected on both igniters.
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|====
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During ascent, the tones will be muted to allow the
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telemetry data to consume the full radio bandwidth.
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During descent and after landing, a ½ second tone will
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be transmitted every five seconds. This can be used to
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find the rocket using RDF techniques when the signal
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is too weak to receive GPS information via telemetry
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or APRS.
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endif::radio[]
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=== Turning On the Power
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Connect a battery and power switch and turn the switch
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to "on". The flight computer will signal power on by
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reporting the battery voltage and then perform an internal self
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test and sensor calibration.
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Once the self test and calibration are complete, there
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are two modes that an Altus Metrum flight computer can
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operate in:
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Flight/Pad::
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The flight computer is waiting to detect
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launch and then fly the rocket. In this mode, the USB
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link is
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ifdef::radio[disabled, and the radio goes into transmit-only mode.]
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ifndef::radio[disabled.]
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The only way to get out of this
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mode is to power the flight computer down. See below for how to get the flight
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computer to come up in Flight/Pad mode at power on.
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Idle::
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The flight computer is ready to communicate over USB
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ifdef::radio[and in packet mode over the radio.]
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You can configure
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the flight computer, download data or display
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the current state. See below for how to get the flight
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computer to come up in Idle mode at power on.
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ifdef::telemetrum,easymega,telemega,easytimer[]
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For flight computers with accelerometers (TeleMetrum,
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EasyMega, TeleMega and EasyTimer), the mode is selected by the
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orientation of the board during the self test
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interval. If the board is pointing upwards as if ready
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to fly, it will enter Flight/Pad mode. Otherwise, it will
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enter Idle mode.
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endif::telemetrum,easymega,telemega,easytimer[]
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ifdef::easymini[]
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For EasyMini, if the USB cable is connected to a
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computer, it will enter Idle mode. Otherwise, it will
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enter Flight/Pad mode.
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endif::easymini[]
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ifdef::telemini[]
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For TeleMini v1.0, if a packet link is waiting to
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connect when the device is powered on, it will enter
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Idle mode, otherwise it will enter Flight/Pad mode.
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endif::telemini[]
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You can see in <<_understanding_beeps>>
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how to tell which mode the flight computer is in.
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=== Using an External Active Switch Circuit
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You can use an active switch circuit, such as the
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Featherweight Magnetic Switch, with any Altus Metrum
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flight computer. These require three connections, one to
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the battery, one to the positive power input on the flight
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computer and one to ground. Find instructions on how to
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hook these up for each flight computer below. Then follow
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the instructions that come with your active switch to
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connect it up.
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=== Using a Separate Pyro Battery
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As mentioned above in <<_hooking_up_pyro_charges>>, one
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lead for each of the pyro charges is connected through
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the power switch directly to the positive battery
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terminal. The other lead is connected to the pyro
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circuit, which connects it to the negative battery
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terminal when the pyro circuit is fired. The pyro
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circuit on all of the flight computers is designed to
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handle up to 16V.
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To use a separate pyro battery, connect the negative pyro
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battery terminal to the flight computer ground terminal,
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the the switched positive battery terminal to the igniter
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and the other
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igniter lead to the negative pyro terminal on the flight
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computer. When the pyro channel fires, it will complete the
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circuit between the negative pyro terminal and the ground
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terminal, firing the igniter. Specific instructions on how
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to hook this up for each flight computer will be found
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in the section below for that flight computer.
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Note that you must include a switch in the positive lead of
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the pyro battery for safety, as the on-board power switch
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circuit on our product only controls current flow from the
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the primary or system battery!
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=== Using a Different Kind of Battery
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EasyMini
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ifdef::easytimer[and EasyTimer are]
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ifndef::easytimer[is]
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designed to use either a
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lithium polymer battery or any other battery producing
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between 4 and 12 volts, such as a rectangular 9V
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battery.
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ifdef::telemega,easymega,telemetrum,telemini[]
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[WARNING]
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ifdef::telemini[TeleMini, ]
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TeleMega, EasyMega and TeleMetrum are only designed to
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operate off a single-cell Lithium Polymer battery and
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cannot be used with any other kind. Connecting a
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different kind of battery to any of these will destroy
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the board.
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endif::telemega,easymega,telemetrum,telemini[]
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=== Using Packet Link Mode
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All AltusMetrum flight computers that have a radio can
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communicate with the ground station software for
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configuration and other operations using the Packet
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Link mode. This uses radio communication instead of a
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USB cable. To set this up, the ground station software
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must be configured to the correct data rate, frequency
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and callsign.
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You can monitor Packet Link mode from TeleBT or
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TeleDongle by watching the LEDs. Each time the device
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transmits, the red LED will flash. When the link is
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busy, or when the link is not working, the device will
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transmit 10 times per second, so the LED will flash
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rapidly. When the link is working and there is no data
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to send, the link will flash once per second, and the
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LED will flash more slowly.
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