通过超声波模块与单片机连接，进行测距。超声波测距原理是在超声波发射装置发出超声波，它的根据是接收器接到超声波时的时间差，与雷达测距原理相似。 超声波发射器向某一方向发射超声波，在发射时刻的同时开始计时，超声波在空气中传播，途中碰到障碍物就立即返回来，超声波接收器收到反射波就立即停止计时。(The ultrasonic module is connected with the microcontroller to measure the distance. The principle of ultrasonic ranging is that the ultrasonic device emits ultrasonic wave, which is based on the time difference between the receiver and the ultrasonic wave, which is similar to the principle of the radar ranging. The ultrasonic transmitter launches an ultrasonic wave in a certain direction, and starts the time at the time of the launch. The ultrasonic wave propagates in the air, and immediately meets the obstacle on the way, and the ultrasonic receiver stops the time immediately after receiving the reflected wave.)