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This is a single zone alarm - with automatic exit, entry and siren cut-off timers. It will accommodate all the usual types of normally-closed input devices - such as magnetic-reed contacts - foil tape - PIRs etc. But it's easy to add a normally-open trigger.

When the alarm is activated - the siren will sound for a fixed length of time. Then it will switch off - and remain off. The alarm will not re-activate.

I've used a 12-volt supply in the drawing - but the circuit will work at anything from 5 to 15-volts. All you need do is select a siren, buzzer, and relay to suit the voltage you're using.

Parts list