Abstract: The ultrasonic ranging application is extremely widespread. After the feasibility and reliability has been analysised, the structure design technique was established. This article introduces an ultrasonic distance measurement based on the AT89C51 single-chip computer, the system according to ultrasound in the air reflection principles of the dissemination. And it uses the ultrasound sensor as interface components for the application of the distance measure based by single-chip computer technology and the margin of time that ultrasound transmit in air, thereby the systems of design of ultrasonic test comes into being. The system primarily composed by the four modules : the controller module,ultrasonic launch module, ultrasound receiving module and display modular. The I/O ports of the 51 single-chip computer were used to cause the ultrasonic transducer to send out the 40kHz ultrasonic wave. The reflected signal enter the 51 after the enlargement and feedback circuit, and the system will complete the range finder by debugging the corresponding distance. This design can realize 3 meters in range finders, with the 7 centimeters blind spot, The system have the LCD demonstration.
Keywords: ultrasonic, ultrasonic sensor, AT89C51 single-chip computer, LCD display unit, range finder