HC-SR04测距,本传感器采用HC-SR04超声波测距模块，该模块可提供2cm-400cm的非接触式距离感测功能，测距精度可达到3-it is a UltraSonic HC-SR04 testcode,platform is AVR.You can study tht method of HC-SR04 sensor.

使用avr实现HC-SR04的测距功能，精度为1cm，精度较高-HC-SR04 achieved using avr ranging functions, accuracy 1cm, high precision

超声波测距模块及显示模块，含C51 PIC,并且有比较丰富的参考资料！-Ultrasonic ranging module and display module, including C51 PIC, and have relatively rich reference material!