Obstacle detector
The reflection of sound waves with an ultrasonic transducer is used in our obstacle detection technique. The ultrasonic transducer transmitter releases a burst of ultrasonic
sound waves toward the air and receives a corresponding echo (19). The echo amplitude also depends on the reflecting material surface and the sound absorption.
The distance between the transducer and the object can be calculated by the reflection echo time and the speed of sound in the air, as shown in Equations (1) and (2):