Tag Archives: Siren

Automatic Intruder Alarm

This is a simple single-zone burglar alarm circuit. Its features include automatic Exit and Entry delays and a timed Bell/Siren Cut-Off. It’s designed to be used with the usual types of normally-closed input devices such as – magnetic reed contacts – micro switches – foil tape – and PIRs. But it can be Easily Modified to accept normally-open triggering devices – such as pressure mats.

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