Design and Testing a Remote Laser Listening System

Abstract

<jats:p>Laser listening device is one the modern and powerful techniques in the field of remote sensing. In this research a simple system was developed to remote sensing the audio signals. The reflected laser spot position variation is dependent on the variation in the reflector position. A suitable receiver was designed for receiving and demodulating the audio signal. Light dependence resistance (LDR) was used in the receiver as an optical detector and it was tested in three cases. This system was tested to remote sensing the audio signals up to 5m and it is easy to increase this distance. The results of this research are promising and one can conclude that this system can be used efficiently to sense the microvibrations, but with a careful alignment. </jats:p>