The photo triggers long range beam breaker consists of two boxes a transmitter and receiver the transmitter sends out an infra red beam which is picked up by the receiver which in turn is connected to the main controller to set up simply point the transmitter at the receiver and switch it on the beam width is 30 degrees so it is easy to line them up the receiver led goes out to indicate a good signal and lights up when the beam is broken anything breaking the beam will fire the trigger o