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Don’t be scared by words like resistors, capacitors, and weird symbols like Ω. It is very easy to make your own Interrogator 3000 lie detector. You should build this and have it around for emergencies. Most Radio Shacks will have these parts. The speaker, nine volt battery clip, wire, and paper clip should be easy to find in junk that is lying around. You don’t even have to worry about confusing circuit boards.

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. When these fight-or-flight nerves are aroused, your body will sweat a little. The sweat, a lot or a little, will cause the electricity to flow in higher amounts and produce a higher pitched sound from the lie detector’s speaker.
Once built, to test this out put your fingers in paperclips and connect the battery. Now lick your fingertips and try this again. The pitch should be higher. Just so you know, Chef from South Park has a very low pitched voice. My sister Janice and all the princesses in Disney movies have high pitched voices.
The problem with this lie detector is that you can’t fake lies. If I said, “My name is Barack Obama,” it wouldn’t increase the pitch. This is because my nerves were not aroused, I was just joking around. The more you can get someone to take your lie detector seriously, the better.

(Note: If President Barack Obama is reading this I just wanted to say thanks for reading my book!!)






  1. Make a copy of the circuit board. Be careful not to enlarge it. Cut along the dashed outside line.

  2. Fold it over on the fold line. Add glue to each side. Glue it around a piece of cardstock from some junk mail. This will make your circuit board stronger.

  3. Use a thumbtack to poke a hole on every black dot. There are 16 total.

  4. Add the capacitor through the labeled holes. It doesn’t matter which leg goes through which hole.

  5. Add the transistors to their correct spot on the circuit board. Make sure that the flat part of the transistors faces you.

  6. Add the resistors. The colors should be in the proper order as listed on the circuit board.

  7. Insert your short (only a few inches long) jumper cable. Make sure each end is stripped of the plastic coating.

  8. Poke your touch cables through the circuit board. Make sure each end is stripped.

  9. Turn the circuit board over. Follow the picture and twist together the wires and components.

  10. Add your alligator clips. The green should connect to the positive (+) terminal of the speaker, red to the positive (+) terminal of the battery holder, and the two black wires should connect to negative (-) terminals on both the battery holder and the speaker.

  11. If you built an enclosure for the lie detector, now’s the time to put it in. It looks a lot cooler if you do.

  12. If you want, wrap the touch wires around a marker to give them a cool spiral look.

  13. Twist the stripped end of the touch wires around the paper clips. Make sure it is the short end of the paperclip that has one loop, not two.

  14. Connect the battery to test the circuit. If you don’t hear a sound, quickly disconnect the battery so you don’t burn out the transistors. Check that all of your components were added in the correct spot and make sure your transistors and resistors are facing the correct way.

  15. Put a finger from each of you subject’s hands in the two paper clips. 






Once completed, don't forgot to print out your detective badge and start solving crimes in your town.