What Is a Motion Detector
A motion sensor is an electronic device that is used in conjunction with an alarm panel to sense motion. The motion sensor can be used to monitor a larger area which might include all of the windows and doors in an entire room. In some cases this can be cost effective so that you do not have to have a security door contact on every door and window.
There are 3 types of motion sensors:
Passive Infrared Sensor Microwave Sensor Ultrasonic Sensor These sensors often include a feature called Pet Immunity which will prevent the home alarm from being set off by a pet.
Passive Infrared Sensors (PIR) This type of detector works by sensing changes in heat within its field of vision. When there is a rapid change of heat then the sensor will trigger an alarm. Since this type of sensor works by detecting a rapid change in heat a person standing stationary will not trigger the alarm. Slow temperature changes do not trigger the alarm so heating and air conditioning will not set off an alarm. This helps keep false alarms to a minimum.
Microwave Sensor These type of sensors emit pulses of microwave when they are activated using the reflections of energy to detect movement. The inherent problem is that they penetrate most surfaces except metal so they can be prone to false alarms. These sensors should be used for very specific cases that require a longer range of coverage. If care is taken when they are being placed then they can be an effective security device.
Ultrasonic Sensors Ultrasonic sensors work in one of two ways: some (active sensors) are built with emitters that send out pulses of sound higher than humans can hear, reading the resulting echoes to detect movement; others (passive sensors) come equipped with receivers that listen for sound. Ultrasonic sensors are some of the best and most expensive types of motion detector available.
Motion Sensors are an essential part of a home security system but they must be used correctly. Many home owners think that they can save money by using a motion sensor instead of protecting each door and window with an individual contact. The problem with using motion sensors in this way is that the intruder must already be inside your home before the alarm will trigger. If a burglar enters your home and the alarm is triggered then they will make sure to take something for their efforts. The worst case is that they may harm a family member once inside the home.
When it comes to False Alarms the motion sensor is typically the cause. You must make sure that the motion sensors are properly placed and tested. You must also make sure to keep the sensors clean. Resources: http://www.elecleco.com http://ezinearticles.com/?What-Is-a-MotionDetector&id=7498838
Thank you for reading!