Hi Stanley,

Regarding your second question, I've used the Philips compass chip, the KMZ52. Take a look at it...you will find that direction sensing is a bit more complex than you're thinking it is. The apnotes give a good explanation of the X and Y direction magnetic flux sensors, calibration procedures, and the sine/cosine calculations required to get the final direction.

How much accuracy do you require? Eight points of the compass is relatively simple.

Dennis