Instructables

How to make a cheap, simple, and effective alarm system

Picture of How to make a cheap, simple, and effective alarm system
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This is my fourth instructable. It is on how you can make an alarm without any expensive equipment. It takes very short to set up too.

materials

wire
bar magnet(s)
reed switch
tape
paper
battery with holder
buzzer
door
Intruders:)





result
 
 
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Step 1: Step one: battery

Picture of Step one: battery
attach the battery/holder to the wall with tape (see pic) attach wires flowing downwards.

Step 2: Step two: attaching the reed switch

Picture of Step two: attaching the reed switch
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attach the reed switch to the hanging wire from the battery close but not touching the door

Step 3: Step three: bar magnet trigger

Picture of Step three: bar magnet trigger
when a reed switch comes close to a magnet both parts attract causing them to come together and continue the flow of electricity. Attach the magnet with tape to the inner part of the door so it can swing.

Step 4: Step four: attaching the buzzer

Picture of Step four: attaching the buzzer
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add a wire flowing from the other side of the reed switch. This should then go to the buzzer. The attach an other wire flowing up (see red wire)

Step 5: Finishing touchings

Picture of finishing touchings
attach the final two wires so that the circuit is complete now when the bar magnet comes close to the reed switch it will buzz. To make a disarmer put a piece of tape under the magnet and reed switch (see pic). Now you can put a piece of thick paper between the magnet and reed switch from the outside and be able to walk in without it going of. You may have to adjust it to your desire. Thanks for viewing my instructable!  
abagas4 months ago
Hey, I have a question. In your picture the bar magnets were put on the door and get taped in it, so when the door open, the bar magnets get touch with reed switch or what?
Thank you. Sorry for my bad english
Yeah, maybe I should stop pranking him. Before he pulls the ULTIMATE PRANK! (Nervous)
patriots8888 (author)  K'nex gun builder2 years ago
then you just have to top that prank!
Cool! I used it to prank again. I put it in my brothers bedroom and plugged it underneath his bed. When he went to bed I snuck in his room, and turned it on. Then I tried to hide when he heard the buzzer, and man he was so FREAKED OUT!
patriots8888 (author)  K'nex gun builder2 years ago
lol thats awesome
jensenr303 years ago
Cool. reed-switches are the best.
patriots8888 (author)  jensenr303 years ago
thanks
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