Homemade digital compass
Some time ago OddBot posted this circuit for a homemade digital compass based on hall effect sensors:
Unfortunately CircuitBurn couldn't make it work. However I'm inclined to try again. A cheap DIY compass would be great.
So if anyone has ANY idea as to how this could be achieved let's hear it. It could be an improvement on OddBot's circuits or something completely different and wacky :D