Active Infrared sensors transmit and measure the reflection levels of infrared light. They take a snap shot of the reflection levels from the ground. Any change in the properties of the reflected wave will indicate that a person or object is in the detection area, causing the sensor relay to activate and the door to open. Our Active Infrared sensors are easy to install and adjust. They can detect motion and static presence, and have a high immunity to the negative effects of external influences such as reflections, sunlight and artificial light. Microwave Sensor TechnologyMicrowave sensors operate on the Doppler principle. They register and compare the frequency of transmitted and reflected signals. People and objects cause disparities between the emitted and received frequencies as they move through the detection zone, thereby activating the sensor relay, causing the door to open. Microwave Sensors have a large elliptical detection area. They can detect motion only, detect uni or bi-directional traffic, and can activate the swing-side of swing doors without detecting door movement. Combined Technology SensorsCapitalising on the merits of both infrared and microwave technology. Combined technology sensors, look to capitalise on the merits of both infrared and microwave technology by combining both into one sensor. The microwave part of combined technology sensors allows for the detection of a fast moving traffic or pedestrians at large distances from a door, thus ensuring timely door opening. The unidirectional detection nature of microwave sensors also decreases door hold open time, thus reducing building energy losses. Microwave technology’s lack of safety properties is overcome by the addition of a three-dimensional infrared safety curtain to protect pedestrians from contact with a moving door.