Tag Archives: Automatic

Audio Auto Shutoff

I have had many requests to design or provide circuits for graduation projects. Yes, I had to build a graduation project too before receiving my degree. Even though I have always refused to design circuits for this situation, I thought it might be helpful for you to see what I built for my project many years ago when I graduated in 1978. I will also provide a more detailed description of the circuit than I normally do. Hopefully, this may help some of you with your projects.

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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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