This paper reports on a thin and small ultrasonic distance sensor which is composed of a thermoacoustic transmitter and a piezoresistive cantilever receiver. The fabricated sensor can measure proximal distance about 10mm by using a very short transmission time ultrasonic about 60μs which is almost the same time of the reflection time in 10mm distance. The ultrasonic is a 2 cycles’ burst mode sinusoidal wave. To emit such short ultrasonic we use a thermoacoustic transmitter. The thickness of the fabricated sensor is less than 2mm, and the size of this sensor is 10mm x 10mm. This fabricated sensor measures distance from 10mm to 30mm with accuracy about 15%. This small proximal distance sensor is widely useful, for example, for a proximity sensor of robot hands.

References :
Yasushi Hashimoto, Akihito Nakai, Hajime Kawano, Kiyoshi Matsumoto and Isao Shimoyama, "Thin and Small Ultrasonic Distance Sensor with Thermoacoustic Transmitter and Piezoresistive Cantilever Receiver," Proceedings of the 4th Asia Pacific Conference on Transducers and Micro/Nano Technologies, 2008.