Optical Reflective Gear Tooth Sensor with Application to Rotational Speed Measurement

An optical reflective gear tooth sensor is described in this paper. Mathematical models of optical and electrical signals are derived after theoretical analysis and calculation, and the waveforms are plotted as a reference of design by MATLAB programming. The test results show that the optical reflective gear tooth sensor with collimation LED can work well in a wide range of sensing distance, and the optical reflective sensor can detect a longer distance than Hall-effect sensor with high measuring accuracy. The developed optical reflective gear tooth sensor can be applied to various kinds of rotary speed measurement, especially where the electromagnetic interference or a wide sensing distance of sensor is required.