Mon Aug  8 10:13:29 PDT 2011 Kevin Karplus

This board uses a 4-hole Arduino template (2 screws for either Arduino
or Arduino Mega) and connects to the motor power on the open end opposite
the USB port).

If the switching regulator is installed, then the HexMotor board
supplies 6.25v to the servos and (via a jumper that can be removed) to
the Aduino Vin pin.  If the Arduino is getting power separately (for
example, from the USB connection), then the jumper may be removed.
If the Arduino is separately powered and there are no servos, then the
switching regulator, the 11.8kohm resistor, and one of the
electrolytic capacitors can be omitted.

The board has a reset button (since the Arduino reset button is
covered up) and LEDs to show availability of +5v and +6.25v supplies.

The motor power has the following constraints:

	low	high
	6v	40v		for TLE-5206 chips
	0v	25v		for capacitors
	8.25v	36v		for PTN7800W (6.25v+2v)

The capacitors should probably be replaced by ones with higher voltage
ratings if motor supplies over 20v are used.  So, realistically, the
motor voltage input should be between 8.25v and 20v.  If the switching
regulator is not used (no servos and Arduino separately powered), then
the motor voltage supply can go as low as 6v.


Mon Aug  8 12:56:11 PDT 2011 Kevin Karplus

I'm not sure how big to make the series resistors for the LEDs, since
I don't know how bright the cheap (no data sheet) LEDs I have are.
A 1kohm resistor should be safe (providing something like 2-5mA), but
I don't know if that will be bright enough to see the LEDs clearly
when they are in the dry box.  I tried a 1.5kohm resistor with one of
the green LEDs and it seems adequate with the 5v supply, so 1kohm
should provide more than enough current.