This is for teacher's looking to purchase a classroom set of lie detectors. If you're looking to purchase just a few, please click here.
I've priced the lie detectors at 50 cents each. To qualify for this price, you need to place a minimum order of 10. Please use the quantity to tell me how many you would like for your classroom. This is a great project. Please also email me (firstname.lastname@example.org) your school or club's name. I'll send a video saying hi and encouraging them.
Lie Detector Essentials Details...
Make your own real-working lie detector. Provide yourself or others a great learning experience with a kit ideal for beginners or experimenters. This kit provides you with the essential elements needed to build this simple lie detector. It contains a 82KΩ resistor, 4.7KΩ resistor, 3906 transistor, 3904 transistor, and a .01 mfd ceramic disk capacitor.It also contains a paper circuit board template. This paper circuit board is used in place of a real circuit board. So in place of soldering, you only need to twist your connections together.
To build a lie detector, you will also need some wire (18 gauge preferred), a 9 volt battery and battery clip, 2” Ω speaker (many other speakers will work too), 2 alligator jumper cables, and 2 paper clips (metal ones, with no plastic coating).
This simple, sound-producing circuit is a perfect for anyone looking to experiment. The same circuit can be used to make many different alarms and musical devices. See www.deweymac.com for more details.
The lie detector works on a principle called galvanic skin response. Basically, it detects sweat, which usually happens when someone lies. Sweat increases the conductivity (ability to let electricity pass through) of your skin. Your sympathetic nervous system controls the sweat glands on your fingertips and is completely subconscious (not controlled by you). When caught in a lie, these fight-or-flight nerves are alerted. Your body will sweat a little. The sweat will cause the electricity to flow in higher amounts and produce a higher pitched sound from the Interrogator 3000.