Rooftop Laser Trip Sensor

A near-invisible laser sensor projecting a thin beam across a doorway, corridor, or rooftop access point, silently alerting the user the instant anything breaks the beam, giving early warning of an approach with nothing visible to trip over or notice.

Fine airborne particles like heavy dust, smoke, or fog can occasionally scatter the beam enough to trigger a false alert, and it covers only the single straight line it's aimed along.