基于AT89C52的超声波模块，包含原理图和PCB，用AD9以上版本打开-AT89C52 based ultrasonic module, including schematics and PCB, with more than AD9 version to open

快递柜锁控板的原理图，采用ALTIUM DESIGNER设计(The schematic diagram of the lock control panel of the express cabinet is designed by using ALTIUM DESIGNER)