倒车雷达源代码，超声波发射，接收，测距。-source code reversing radar, ultrasonic transmitter and receiver, location.

89C51单片机通过微波模块GH719检测启动,用于检测移动物体,物体移动时产生频率可变方波信号,物体不动时产生连续低电来信号。有物体移动时，逐级输出PWM信号，调整LED亮度-89C51 microcontroller is initiated by the microwave detector for detecting a moving object, a variable frequency square wave signal