ULTRASONIC WAVE DOPPLER TYPE INTRUSION DETECTOR FOR VEHICLE

摘要

PROBLEM TO BE SOLVED: To provide a ultrasonic wave Doppler type intrusion detector for a vehicle by which the Doppler shift amount caused by a human motion is detected with intermittent action, and also by which human intrusion is detected while reducing the amount of power consumption. SOLUTION: A microcomputer 100 starts arithmetic processing every time a trigger pulse from a trigger circuit 90 is output. Under the control of the microcomputer 100, a analog switch 80, when turned on, supplies electricity from a battery B to a ultrasonic wave transmitter 10a, a driving circuit 20, an oscillating circuit 30, a ultrasonic wave receiver 10b, an amplification circuit 40, a comparison circuit 50, a phase difference output circuit 60 and a BPF 70, while when it is turned off, the switch cuts off the electricity supply.