Design of Rotate Speed Sensor Based on MR Elements

Abstract

In order to meet the needs of speed measurement for rotation system, a rotation sensor which based on the principle of Anisotropic Magnetoresistive Effect was designed in this paper. This paper presents the principle, detailed hardware circuit, frequency characteristics of the sensor, as well as the valid detection distance. The sensor used MR elements as the sensing element. It turned the change of the magnetic gear’s rotation speed into the change of the circuit’s output signal and ultimately achieved contactless rotation measurement of the magnetic gear. The hardware circuit of the sensor includes five parts: signal collection, impedance matching, signal amplification, digitalization processing and signal output. The tests show that its operating frequency ranges from 2 Hz to 6 KHz.