Design, build and evaluate a distance measurement device using ultra-sound

Abstract

Ultrasound distance measuring is non-contact measuring method – radiation and reception of ultrasound waves. Ultrasound waves are mechanical acoustic waves with frequencies more than 20kHz. Normally human cannot hear frequencies above 20kHz while some animals can. This project describes an ultrasound sensor that is able to measures the time interval between the transmitted and received signal. The system transmits a burst of ultrasound waves towards and then receives the corresponding echo by the receiver. When the first receiver resends an ultrasound wave from first transmitter it will switch on the second transmitter. The second transmitter transmits the wave to the second receiver. Electronics then convert this time interval into a distance measurement using the speed of sound in air.