A Bosch B series panel showing "Missing Battery" on the keypad and the Battery Light on the B series panel lite solid, indicating a missing battery.
Passive Infrared Sensors
A PIR motion sensor is good for most residential and commercial installations out to 40'. If the protection area is further away, you will need a model designed for the extended range or if available, a long-range lens for the model you have on hand. You should always refer to the installation sheet for suitable installation locations, including height. Commonly, most detectors work well between 7.5 and 9 feet above grade.
Multi-Tech motion sensors use a combination of infrared sensing with technology that detects the motion of physical objects. The most common method is to use micro-waves. The motion sensor transmits micro-waves and then "listens" for a change in the echo by using the doppler effect. Only when a motion sensor detects the movement of heat between zones AND senses the physical movement of an object in the protected area will an alarm occur.
Passive Infrared Motion (PIR) sensors have been a mainstay in modern alarm systems from the beginning. They have also been the most common source of unattended false alarms. Understanding how PIR sensors work provides an installer with the knowledge of how to best select and locate a PIR sensor which will increase the protection they provide and reduce nuisance alarms.
A PIR sensor is a small device with two sides. In our example, we call them Side A and Side B.