A single beam triggered alarm about ticking time-bomb ‘Aero’ concrete that forced 100 schools to close Sian Elvin Published September 1, 2023 2:06pm Updated September 1, 2023 3:56pm Comments ...

This is an Infrared based Broken beam alarm to protect doors and entry passages. It gives a loud alarm when somebody crosses the Invisible Infrared barrier. It can protect the doors both day and night ...