interfacing of at89c2051 with 7 segment display
If your requirement is for measuring the distance, this project kit from "www.united77.com/projects.htm" may help you. This Microcontroller-based Ultrasonic distance meter project employs 40 kHz ultrasonic transducers for distance measurement up to 2.5 meters. Ultrasonic transducers measure the amount of time taken for a pulse of sound to travel to a particular surface and return as the reflected echo. This circuit calculates the distance based on the speed of sound at 25°C ambient temperature and shows it on a 7-segment display. Some of the main components used in this project are : AT89C2051 microcontroller, two 40kHz ultrasonic transducers (one each for transmitter and receiver), current buffer ULN2003, operational amplifier LM324, inverter CD4049, four 7-segment displays, five transistors and some discreet components. Good Luck