Faculty Advisor

King, Brian M.


The purpose of this project is to design and construct a device that is capable of eavesdropping on a conversation form a distance away. As people are talking in a room, they create sound waves that travel through the air. These sound waves vibrate the window, flexing it in an out. A laser beam is aimed at a window and the deflection angle of the reflected beam is proportional to the sound intensity. The photodiode then converts the changes in intensity of the reflected light due to the angle variation into an electrical signals. The goals of the project are to reproduce the sound of the conversation at the distance away via a beam modulated by a surface such as a window as well as to design a device at a lower cost than current products on the market.


Worcester Polytechnic Institute

Date Accepted

January 2005


Electrical and Computer Engineering


Engineering Physics

Project Type

Major Qualifying Project


Restricted-WPI community only

Advisor Department

Electrical and Computer Engineering