Contactless Vibration Sensing and Acoustics Wave Detection Based on Laser Feedback Interferometer

In this paper, the use of laser feedback interferometer to detect the minute displacement of low frequency vibration from a piezo actuator and acoustics wave detection from a standard speaker are presented. The preliminary results of time domain and its corresponding FFT graphs are illustrated. The acoustics signal is further investigated by varying the distance of the speaker with the laser feedback interferometer optical path. The results show that measurement of vibration as low as 5 Hz and the detection of acoustics wave are achievable.