Patent attributes
A wireless, automatic door obstruction detection system for protecting a motorized door or gate by signaling various hazardous conditions and reacting to said conditions by signaling control means. The invention utilizes wireless infrared emitter, receiver and controller apparatus. Infrared pulse timing data is sent as pulse repetition rate changes depending upon battery condition. In a preferred embodiment of the invention, the photoelectric transmitter emits timed pulse groups to present control information differentiating between a good battery and a low battery condition in the wireless transmitter. A wireless photoelectric transmitter extends the time period between pulse groups to indicate a low battery condition. A low battery condition signaling thereby presents a low power drain condition allowing for an extended period of low battery condition signaling.
