The Laser Listener

Yeah, another unique entry for our “Most Bizarre” Section! This time how about building a less than 5$ laser listener!

This hack is freakin’ awesome infact its exactly what I have been looking for (issues with my little brother/sister) - No more secrets hidden away from me now

Now the hack states you can listen from “hundreds of yards away” but thats a bit extreme, you would need a better laser and you would have to not only setup a laser to hit the window, but also find the reflected light.

You?d basically have to be perfectly perpendicularly positioned (or close enough) to even find the reflected light beam (& that?s assuming you have a bright enough laser to reflect off of a transparent window). (Thanks tmasman)

The Procedure - How about a video!

Laser Espionage Microphone (how-to) - video powered by Metacafe

?In a microphone, sound waves (differences in the pressure of air) cause a diaphragm to vibrate back and forth, altering its resistance to an electric current. When an electric current passes through said diaphragm, the output forms a complex signal which can then be reinterpeted by speakers or a recording device as sound. The device shown here works in a very similar way. Sound bounces off of a window, causing minuscule vibrations (acting like the microphone?s diaphragm). When a laser is trained on the window, its reflection will vibrate with the sound. The laser?s reflection, if converted to an electrical signal can now be recorded as sound. I will outline how I made my own (cost me $3, hope yours is the same or less) - the technically savy among you will spot the countless variations possible on this basic idea.?

I will be building one probably on the weekend, I might put a small video together also for your benefit enjoy!

The full how can be found in the original thread by clicking here.