Mac Cody has been playing with digital compass electronics, read about his new project.

“I wanted to optimize the use of four data bits of an I/O port. That implied that I wanted to have sixteen points of precision on my digital compass. If I wanted to read in the data serially, even higher precision could potentially be obtained. I toyed with one digital compass design that uses a PIC processor, two of LED-optotransistors pairs placed in quadrature, and a compass with an encoder disk with varied tone shading to represent orientation. The PIC processor would implement two successive approximation analog-to-digital converters to measure the position of the encoder disk. I decided that this was far too much work to get only sixteen unique compass positions.”