WORKING PRINCIPLE - Ultrasonic Sensors are widely used for non-contact proximity, presence and distance measuring applications. These devices work on a similar principle of sonar which evaluates the target by interpreting the echo from sound. It emits a short high frequency sound wave and evaluates echo which is reflected back from the target. Sensors use the time interval between sending the sound waves and receiving the echo to determine the distance of the target. Most of the ultrasonic sensors are equipped with temperature compensation circuits to avoid changes in readings due to temperature changes. Also, after calculating the distance it determines and checks the predefined range. If it satisfies the condition the alarm goes on i.e., the buzzer beeps.
