An ultrasonic rangefinder has a working range of 30 mm to 450 mm and operates at a 375 Hz maximum sampling rate. The random noise increases with distance and equals 1.3 mm at the maximum range. The range measurement principle is based on pulse-echo time-of-flight measurement using a single transducer for transmit and receive. The transducer consists of a piezoelectric AlN membrane with 400 µm diameter, which was fabricated using a low-temperature process compatible with processed CMOS wafers. The performance of the system exceeds the performance of other micromechanical rangefinders.
May 23, 2011
Przybyla, R. J., Shelton, S. E., Guedes, A., Izyumin, I. I., Kline, M. H., Horsley, D. A., & Boser, B. E. (2011). In-air rangefinding with an AlN piezoelectric micromachined ultrasound transducer. IEEE Sensors Journal, 11(11), 2690-2697.