Hall-effect Sensor
* The sensor was designed at SIO.

* The Hall-effect IC is an Allegro A3141

* The mating (cable) connector is an RMG-3-FS with the following pinout:
	1 - wht - Ground
	2 - blk - Hall Signal
	3 - grn - +5 V

* Pin 1 is large, 2 and 3 are counter-clockwise on the bulkhead connector.

* The A3141 sensor require 9 mA worst case. The EZ17 motor driver has a 200 ohm resistor (data sheet is wrong) in series with the 5 V supply to the A3141. This means that the A3141 may only see 5 - (0.009 * 200) = 3.2 V. This is below the A3141 minimum supply spec of 4.5 V, so the resistor on the EZ17 must be reduced. It can be no more than 0.5 / 0.009 = 56 ohms. To be safe we should use 22 ohms. The resistor is R27 on the bottom of the EZ17.