odel 405 Passive Infrared (PIR) Intrusion Sensor is an advanced stand-alone sensor specifically designed for outdoor intrusion detection applications. Two curtain-shaped sensing patterns detect intruders by sensing the temperature (heat radiation) difference between the background scene and that of the intruder. Through the use of the latest detector and signal processing technology, Model 405 is able to operate in almost any environment. Two stage optical filtering and Adaptive Threshold Decoding (ATD) ensure reliable operation under changing environmental conditions. Nuisance alarms from rain, snow, wind, and fog are virtually eliminated. Model 405 electronics and optics are housed in a rugged ABS enclosure. The universal mounting bracket allows mounting to flat sur faces or up to 4” (100mm) O.D. posts. An internally regulated heater prevents the optical mirror from clouding in cold weather. The heater is independent of the sensor electronics and operates from 12 volts AC or DC. Set-up and adjustment are easy to accomplish. Simply aim the sensor slightly downward into the area that you wish to be protect, apply power and allow a few minutes for the sensor to establish a reference level for operation. Perform a walk test and adjust sensitivity to provide optimum detection.