Dynamic short distance estimation using ultrasonics

This paper describes the practical implementation of a dynamic distance indication system using ultrasonic waves. The distance is measured using pulse echo method, in which the signal is transmitted by an ultrasonic transducer, reflected by an obstacle and received by another transducer where the signal is detected. The time delay between the transmitted signal and the received one is measured using Microchip PIC16F877A microcontroller which controls the signal transmission, reception and distance estimation. The code for calculation of the distance is developed using PIC ASM and the code is programmed into the microcontroller using MPLAB IDE. The accuracy of the distance depends on the environmental temperature as the speed of sound in air varies with temperature.