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diff --git a/doc/telemetrum.inc b/doc/telemetrum.inc new file mode 100644 index 00000000..7c9dadb5 --- /dev/null +++ b/doc/telemetrum.inc @@ -0,0 +1,85 @@ +== TeleMetrum + +	.TeleMetrum v2 Board +	image::telemetrum-v2.0-th.jpg[width="5.5in"] + +	.TeleMetrum v1 Board +	image::telemetrum-v1.1-thside.jpg[width="5.5in"] + +	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 in the v2 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 positive battery terminal to the pyro +		charges must be done separate from TeleMetrum, by soldering +		them together or using some other connector. + + +		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. +  | 
