Instructables

Lie Detector

I want to make a lie detector with my Arduino. I know that when people lie, their skin is supposed to change its resistance. What kind of change are we talking about? I know I can monitor the light in a room with a photoresistor, but how would I go about doing this?

bumpus6 years ago
When someone makes a lie-detector kit, tell me.
Plz?
. Try searching for one.
Login258 (author)  NachoMahma6 years ago
Aha haha. Hm. Actually, I did search for it, it brought results that used a method I didn't want to use. But I ended up using a modified version of it... Yeah basically I used a 555 timer to make a tone that I play through a speaker. Then, I measured my resistance, I got about 2 Megaohms. So I changed all the resistors and capacitors in the circuit until I got a good level and tested it out with my friend, it works! Unbelievable, but it does! It lets you know if the person is lying before they even answer, they get very nervous...
A.C.E. Login2582 years ago
This is a really late reply, but did you use 2 little pads that people put their fingers on to measure the skin resistance? (for your arduino lie detector..) If so, what did you make the pads out of?
Teehee.
really? wow thats kinda cool i didnt know that
guyfrom7up6 years ago
supposedly you can just do it with a 2n3904 and an led/voltmeter