汽车速度与距离监测及自动刹车系统:通过超声波及霍尔传感器监测车辆与前方障碍物之间的距离与此时车辆的实时速度，并将数据传送到LED显示屏上，通过单片机把得到的数据与事先设定好的车速和安全车距进行比较，由此判断该车辆是否安全，若不安全则由单片机控制执行机构进行刹车。(The car speed and distance monitoring and automatic braking system through real-time monitoring of vehicles and the speed between the ultrasonic sensor and the Holzer front obstacle distance with the vehicle, and transmits the data to the LED display, through the microcontroller to get data with the preset speed and safety distance comparison, judging whether the vehicle safety, if the security is controlled by the single chip computer brake actuator.)