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invention

Door Alarm

by torsten

Published on October 26, 2016

Don't want your little sister entering your room without you knowing? Alarm goes off when the door handle is turned.

How To Make It

1

Create circuit

1

Create circuit
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2

Grab a piece of cardboard and put a strip of foil on the back. Punch a hole in the middle of the foil and cardboard. Attach one lead from the circuit to the foil covers cardboard

2

Grab a piece of cardboard and put a strip of foil on the back. Punch a hole in the middle of the foil and cardboard. Attach one lead from the circuit to the foil covers cardboard
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3

Get a piece of string and attach one of the leads from the circuit to a ball of foil wrapped around one end of the string. Put the string through the hole in the cardboard

3

Get a piece of string and attach one of the leads from the circuit to a ball of foil wrapped around one end of the string. Put the string through the hole in the cardboard
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4

Attach other end of the string to the door handle and tape the cardboard above the handle at a spot where the foil end of the string is almost connecting the circuit

4

Attach other end of the string to the door handle and tape the cardboard above the handle at a spot where the foil end of the string is almost connecting the circuit
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