Time delay door alarm

Time delay door alarm

Ever accidentally left your front door ajar and had a pet escape? [BlackCow] came up with a simple solution to this problem. The circuit is fairly rudimentary but a great example of using the basics to get the job done. Now, instead of having an alarm that sounds as soon as the door is open, he has a 30 second delay. This helps avoid the “boy who cried wolf” effect also known as the “vista security warning” effect of being bothered too many times for a non issue.  We also have to say that we like his taste in blog layouts.

[via Hacked Gadgets]

Via Hack a Day, Published: 2010.03.07

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