HC_SR04超声波模块测距并使用一个8段共阳极数码管对距离进行粗略显示。使用STC89C52单片机。可以轻松在此代码基础上进行扩展，从而控制直流电机等外设（只需要更改if语句中的内容）-HC_SR04 ultrasonic ranging module and use an 8-segment common anode LED display on the rough distance. Use STC89C52 microcontroller. In this code, you can easily expand on, thereby controlling the DC motor and other peripherals (only need to change the contents of an if statement)