超声波测距学习板，可应用于汽车倒车、建筑施工工地以及一些工业现场的位置监控，也可用于如液位、井深、管道长度的测量等场合。-Ultrasonic Distance Learning board, can be applied to car parking, construction sites and the location of some industrial-site monitoring can also be used such as the level, depth, pipe len