Microcomputer-based phase-discrimination capacitive angular sensor

A capacitive angular sensor with grating-shape is introduced in this paper. It is comprised of emitting, interchanging, and receiving capacitive plates, and works on the periodical signal whose phase is relative to the turning angle when the 8 groups of emitting plates are driven by 8-signals with 1/8 period phase difference. So the angle is measured by discriminating signal phase of the receiving plate. A single-chip microcomputer is used for processing the signal, calculating and displaying the angle. To reject the strong noises in the received signal and increase measurement accuracy, a special amplifier circuit is also used. Finally testing results are given.