基于超声波换能器的来人探测装置

Motion-detecting device based on ultrasonic transducers

许多场合需要照明设备能够根据来人情况自动开关,该装置使用了一对收发独立的超声波换能器,能够在一定空间内有效地探测是否有人通过,并控制照明设备的开关。当它正常工作时,会持续发射一定频率的超声信号。如果有人通过,由运动人体返回的超声信号会因为多普勒效应而产生频率偏移。根据此频率偏移,该装置便可以准确地探测到有人来到,继而打开照明设备,并控制照明设备延时关闭,其延迟时间为15 s^30m in可调。该装置可以方便地安装在多种场合,其正面有效探测距离为1.0~5.5 m可调。

Lightings of many places need to be turned on and off automatically when someone passes. The device, using a couple of ultrasonic transmitter and receiver, can detect effectively anybody moving in a certain space,and control lightings on and off. When it works, the ultrasonic signals of a certain frequency are transmitted. Once someone passes,based on the Doppler effect,the frequency of the signals reflected by the moving body is different from the signals transmitted. According to the frequency difference the device can detect the motion exactly, and torn lightings on and off after a delayed time which can be set from 15 s to 30 min. The device can be installed easily in various places. Its front detecting distance can be set from 1.0 m to 5.5 m.