This circuit simulates the siren of an American police car.
This circuit simulates the “Red Alert” siren from the TV show Star Trek. It uses two 555 timers in the circuit.
This circuit simulates the siren of a British police car. It uses two 555 timers in the circuit.
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.