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A Low-cost range finder using SONAR technology

Submarines navigate underwater by using SOund Navigation And Ranging as the bold letters suggest we commonly call it sonar. The sonar technology uses the concept of acoustic listening to range and navigate. This concept is based on the fact that sound travels at a rate of about 340 meters per second and the concepts of echoes, thus by sending a sound burst and listening to the echo one can determine the proximity of the object where the echo originated. Adding sonar capabilities to your embedded project has never became is easy and this cheap, with just 200 bytes of code and a little soldering you can add proximity, presence detection and distance measurement capabilities to your beloved projects. It uses the PIC16F877A’s PWM to generate the initial 40KHz sound burst while using the PIC’s ADC to detect the bounced back signal. Ultrasonic piezzo transducers are used to transmit the burst and receive its echo. The firmware was written in microC while software induced delay is used to eliminate mechanical echoes that could lead to wrong measurements. Continue reading