超声波发射电路主要由74LS04缓冲反向器和超声波换能器构成，单片机输出方波信号。
超声波接收由CX20106完成，CX20106具有内部前置放大，载波选频，脉冲解调等功能，在接收到超声波时，CX20106的7脚输出低电平。,Ultrasonic transmitter buffer by reverse 74LS04 and ultrasonic transducer consists of single-chip output square wave signal. CX20106 completed by the ultrasonic receiver, CX20106 internal preamp, carrier frequency selection, pulse demodulation functions, when the received ultrasound, CX20106 low output of 7 feet