Build your own laser listening device
This is one of those “it works, and it’s scary” hacking projects. Build your own laser listening device for about $3. Video after the jump.Via Funditor
“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 that can then be reinterpreted 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 savvy among you will spot the countless variations possible on this basic idea.â€
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