Laser mic makes eavesdropping remarkably simple - Hack a Day

Laser mic makes eavesdropping remarkably simple

posted Sep 25th 2010 12:00pm by Mike Szczys
filed under: laser hacks

Here’s a surprisly simple way to build yourself a laser-based listening device. It consists of two modules, a transmitter and a receiver. The transmitter is a set of lasers, one is visible red for aiming, and the other is infrared for measuring the vibration of a surface. Point the transmitter at the window of the room you want to listen in on and the laser can be reflected back to the receiver. The receiver module has a phototransistor to pick up the infrared laser light, and an LM386 audio amplifier to generate the audio signal sent to a pair of headphone. The need to be well-aligned which is easy enough using a pair of tripods. Check out the demo after the break.

Looking for something to do with the leftover laser diodes from this project? Try making yourself a laser microscope.

tagged: infrared, laser, microphone, diode, mic, spy, lm386, listening

Go there...
http://hackaday.com/2010/09/25/laser-mic-makes-eavesdropping-remarkably-simple/