The 555 Door Alarm

Posted on Feb 7, 2014

My door alarm is a small device which sounds an alarm whenever the door is opened. It is ideally used when you want privacy, if you want to know if other people enter your room while you’re in another part of the house, to wake you up if someone enters your room at night, or to potentially scare away thieves who enter without permission.

The 555 Door Alarm
Click here to download the full size of the above Circuit.

I don’t really know how to draw better circuits in seashore and I don’t have or know of software to make it easier for free. The components used to make the 555 timer operate in astable mode are not shown.

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