超声波测距仪设计文档，本设计主要是以74LS04和CX20106A为测距模块，DS18B20用于温度补偿，12864液晶显示，HC-SR04为超声波显示板，语音模块由音频功率放大器LM386、语音芯片WT588D、低压差电压调节LM1117组成。-Ultrasonic range finder design documents, the design is mainly based on 74LS04 and CX20106A ranging module, DS18B20 for temper