Five Options for an Outdoor Motion Detector
Passive Infrared
Most people choose to get an outdoor motion detector that uses passive infrared technology. This system does not emit any energy from the sensor. Instead, it relies on the use of invisible light to detect motion. It is sensitive to infrared light that is generated by warm objects such as people.
Microwave
Another popular option for an outdoor motion detector is the microwave variety. These detectors work by using radio waves. They emit microwave pulses and measure the reflection off of a moving objection. They work just like radar guns used by police officers.
Active Infrared
An outdoor motion detector can also be an active infrared system. Unlike passive infrared systems, these systems actively emit energy from the sensor. An active infrared outdoor motion detector will detect objects that interrupt the beam of radiation emitted from the sensor.
Ultrasonic
One of the next options for an outdoor motion detector is the ultrasonic design. These detectors rely on sound to detect motion. They emit ultrasonic sound energy that is reflected off objects and received by the sensor. An ultrasonic motion detector is one of the most inexpensive systems. However, they can easily set off far alarms when they receive reflections from pets and flying insects. The ultrasonic beams can also be blocked many different materials.
Video
One of the final options for an outdoor motion detector is the video variety. They detect motion in the images of a closed-circuit television camera. The system constantly monitors the images picked up by the television camera and analyzes them for changes in the ambient lighting. They are commonly attached to a VCR that will only start recording once the system detects motion.
These are some of your options for an outdoor motion detector. One of the most common systems uses passive infrared technology that will detect heat generated by warm objects. Microwave detectors work just like radar guns used by police officers. You can also consider getting an outdoor motion detector that emits ultrasonic energy. These systems rely on sound disturbances to detect motion and alert you to the presence of an intruder.
