Anti-Theft alarm

259

02:51:58

This device runs off 2 AA batteries hence the 2 1.5VDC power sources. 

The SPST switch simulates a connector/connection that should be broken as someone tries to steal your laptop from your bag, as example.

The relay with an activation voltage of 3VDC is based on a relay I found online. 

As soon as someone pulls out your item which causes the connection to be broken, the relay no longer gets powered and  the upper circuit is being powered.

The LED is just a placeholder and should be replaced by some more circuitry, like an alarm.

I'm new to electronics and this is one of the first projects I'm planning to build, I highly appreciate comments, ratings and advices!

published 10 years ago

Taz8du29

10 years ago

Nice ! You can use a transistor to achieve this, it will draw less current than your relay (and will be smaller), can be useful if you want your batteries lasting !

wocyloh

10 years ago

Yeah, try a depletion type FET. Your batteries will thank you.

lmccoig

10 years ago

Look for placed for to use Kensington lock with security cable to deter grab and run as some electronic stores do, if you will be high crime area. When in Prague, split second timing of grabbing and jumping off elevators just as elevator doors close has to be considered.

TimoM

10 years ago

Thanks a lot for the tip! I'm new to electronics and am not sure how to use a transistor like that. Could you please explain that to me? Thanks! :)

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