How to Make a Lie Detector (sort Of)

Introduction: How to Make a Lie Detector (sort Of)

This is a machine that could be loads of things. It's basicly a machine that buzzes each time you press a secret switch but it DOES look cool! you can decorate it too to make it look MORE cool! Happy buzzing!

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Step 1: You Will Need:


1x wooden square (base)
1x long thick copper wire with no insulation on (finger holder)
4x long thin copper wire with insulation
1x buzzer (12 volt)
1x 9 volt battery
2x paperclips
2x copper nails
2x short screws (length shorter than depth of base)
duck tape
1x elastic band (or thin string)

Tools and bits:

wire stripper
soldering iron
saw (if you need to cut the wood)
double sided sticky pads
about finger size tube

Step 2: Make and Put on the Finger Holder

get the thick copper wire and wrap it round the about finger sized tube.
take the tube out and bend the ends of the wire into tiny little circles and use the screwdriver to screw the two short screws in to them so the finger holder will be in place.

Step 3: Glue and Make the Hidden Switch

get the two paper clips and bend the outside of one up a little.
mix the two araldites together to make an araldite glue. spread it on the back of the wooden board nd put in the un-bent paperclip in first. then put in the bent paperclip so the upper bit of it is over the un-bent paperclip but they must not touch.

Step 4: Put on the Other Parts (except the Four Wires)

first put on the copper nails by hammering them in with the hammer.
then put on the battery and the buzzer by using the double sided sticky pads to stick on the back of them, then peel off the covers and stick them on the wooden board.

Step 5: Soldering the Four Wires (and Buzzer Wires)

the soldering part. the first wire goes from the positive side of battery to the un-bent paperclip.
then the second wire goes from the bent paperclip to the first copper nail. the third one goes from the first copper nail to the second copper nail. the fourth wire goes from the second copper nail to the finger holder. the extra wires (the wires on the buzzer) are next.
the first buzzer wire is soldered on the other end of the finger holder and the second buzzer wire is
soldered to the negative side of the battery.

Step 6: The Switch Pocket

now we need the duck tape.
stick the duck tape back on itself and roll into a tube and hold it with another piece of duck tape.
stick it on the elastic band or string and stick the elastic band or string on the back of the wooden board.
the pocket is to cover the switch when your not using it so when you put it down it doesn't go of all the time.


now you can pretend to detect your mates lies! you can also use it for other things like a doorbell or burglar alarm.
or anything else that needs a buzzer!


Ben (age 9)

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    3 Discussions


    10 years ago on Introduction

    thanks, guys. I don't know about you but I think the microcontroler is a good idea. how about sticking it on your door so it looks like one of those access to your door things? Ben (age 9)


    10 years ago on Introduction

    you need to solder a microcontroller in there somewhere. dosnt have to do anything, but it makes your "lie detector" look more believable.