基于单片机控制的超声波测距报警系统设计,用8位数码管显示，当测试距离小于200mm开灯2亮，当测试距离继续减小到100mm以下灯1亮。-Microcomputer Control Ultrasonic Distance Alarm System Design, 8-digit LED display, when the test is less than 200mm away from bright lights two when testing continues to be reduced to 100mm from the following one bright light.