I still prefer the compass/North detection thing. One comment suggested something that simply buzzed you as you went past North, like a notch in a balance pot. That was creative and it would be a simpler device, too.
Wade.
Q:Is it proper to eat cheeseburgers with your fingers? A:No, the fingers should be eaten separately.
Mount something in glasses. When facing east, the left arm vibrates. Facing west, the right arm. Facing north, both of them at half intensity. Not just at the points, smooth transition as you turn. You would "hear" which way north is.