Next time you need to do some quick police work, here’s a basic polygraph machine you can build to make catching your crook that much easier. Complete with two modes: pulse, GSR, and breath sampling or audio sampling, there is no way to go wrong with the price. “In audio sampling mode, once a set of 32 sequential samples is acquired, the microcontoller performs a 32 point DCT on the audio signal to extract the frequency decomposition of the subject’s voice.” Next time just be sure to tell the truth.

DIY Polygraph – Link, [via]