Proximity Materials Identification by Simultaneous Measurement Method of Optical and Electrical Properties Based on Impedance Measurement

Abstract

We propose a new proximity sensing method using electrodes and photodiode with the LED for simultaneous measurements of electrical and optical properties of object. In this proposed sensor, impedance between electrodes and photodiode is measured while changing light emission of the LED. The electrical property of object is measured by changing the capacitance between the electrodes, and the optical property of object is measured by changing impedance of between photodiode while changing light emission of the LED. In the experiment, discrimination of six kinds of material and detection of distance was possible. This technique may be applicable to proximity sensor for robot and factory automation.