Initial Commit - Copy from Altus Metrum AltOS

doc/telemetrum.inc

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+== TeleMetrum
+
+	.TeleMetrum v2 Board
+	image::telemetrum-v2.0-th.jpg[width=400]
+
+	.TeleMetrum v1 Board
+	image::telemetrum-v1.1-thside.jpg[width=400]
+
+	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.
+
+	There are two generations of the TeleMetrum design. The
+	major changes after v1 generation are:
+
+	* uBlox GPS chip certified for altitude records
+
+	* Higher power radio (40mW vs 10mW)
+
+	* APRS support
+
+	Otherwise, they're the same size, with mounting holes and
+	screw terminals in the same position.
+
+	=== TeleMetrum Screw Terminals
+
+		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:
+
+		.TeleMetrum Screw Terminals
+		[options="header",grid="all",cols="2,3,10"]
+		|===
+		|Terminal #|Terminal Name|Description
+		|1	|Switch Output	|Switch connection to flight computer
+		|2	|Switch Input	|Switch connection to positive battery terminal
+		|3	|Main +++	|Main pyro channel common connection to battery +++
+		|4	|Main -		|Main pyro channel connection to pyro circuit
+		|5	|Apogee +++	|Apogee pyro channel common connection to battery +++
+		|6	|Apogee -	|Apogee pyro channel connection to pyro circuit
+		|===
+
+	=== Using a Separate Pyro Battery with TeleMetrum
+
+		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.
+
+		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.
+
+		Connecting the switched positive battery terminal to the pyro
+		charges must be done separate from TeleMetrum, by soldering
+		them together or using some other connector. Note that you 
+		must include a switch in the positive lead from the pyro 
+		battery for safety!
+
+		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).
+
+	=== Using an Active Switch with TeleMetrum
+
+		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.
+
+
+		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.
+