I am looking for distance finder based on at89s52 and ultra sonic sensors hc sr04....please help me.

distance finder based on at89s52 and ultra sonic sensors hc sr04

Ultrasonic range finder using 8051 .
A simple ultrasonic range finder using 8051 microcontroller is presented in this article. This ultrasonic rangefinder can measure distances up to 2.5 meters at an accuracy of 1 centi meter. AT89s51 microcontroller and the ultrasonic transducer module HC-SR04 forms the basis of this circuit. The ultrasonic module sends a signal to the object, then picks up its echo and outputs a wave form whose time period is proportional to the distance. The microcontroller accepts this signal, performs necessary processing and displays the corresponding distance on the 3 digit seven segment display. This circuit finds a lot of application in projects like automotive parking sensors, obstacle warning systems, terrain monitoring robots, industrial distance measurements etc.

HC-SR04 ultrasonic module.

HC-SR04 is an ultrasonic ranging module designed for embedded system projects like this. It has a resolution of 0.3cm and the ranging distance is from 2cm to 500cm. It operates from a 5V DC supply and the standby current is less than 2mA. The module transmits an ultrasonic signal, picks up its echo, measures the time elapsed between the two events and outputs a waveform whose high time is modulated by the measured time which is proportional to the distance.

The supporting circuits fabricated on the module makes it almost stand alone and what the programmer need to do is to send a trigger signal to it for initiating transmission and receive the echo signal from it for distance calculation.