possible improvements related to rotational platform

[dlarue]

Great project and nice implementation. I was looking at it and noticed the compass is moving on the plate when it could be mounted on the base and have a pin on the rotating plate which will push a switch or a hall effect switch or even a little photo diode sensor board to know where the rotating plate start position is. By moving the compass off the rotating plate also gone all the wires for the compass through the middle of the plate. The only wires left are the 3 wires for the servo so maybe a simple stereo 1/8" audio jack could be used as a slip joint for the 3 connections the servo needs.

These would allow the geared plate to rotate without worry of wires getting twisted and simplify assembly.