Home Security Motion Detectors

In the home security area, motion detectors are a common and popular means of securing the house and yard. The motion detector can be connected to an alarm or a light, both of which alert the owners that there is possible danger of an intruder.

The motion detector is a security device that uses either an electronic or mechanical sensor to measure movement to detect unauthorized entry. There are 3 main types of sensors used in motion detectors:

• Microwave - this sensor sends microwaves pulses to measure the moving object.
• Ultrasonic - this sends electrical pulses to measure the moving object.
• PIR (Passive Infrared) - measures body heat, but emits no energy.

Modern motion detectors often use a combination of technologies. This tends to make the detector more accurate and reliable, and cuts down on the number of false alarms. One of the major causes of false alarms is animals – when a pet moves in front of the sensor, it is detected as a moving object and the alarm sounds. Many newer models have a “pet-sensitive” function that ignores body mass below a particular weight.

Mechanical Motion Detectors
One of the simplest forms of mechanical motion detection is the tripwire. If a bell or something similar is attached to the wire, it will sound if the wire is knocked or “tripped”. This type of device is easily disarmed, however, by cutting the wire. This makes the device only effective if it can be concealed from view.

Electronic Motion Detectors
The major ways that motion is electronically detected are optical and acoustical. The motion detector can be connected to an alarm, a light or a security camera, or any combination of the three. When movement activates the sensor, the attached security device is activated.

Motion detectors that are employed to provide security for the home are most often connected to a bright light. This serves a dual purpose – it illuminates an intruder, and probably scares them away, but it also provides light for family members returning home after dark. This prevents falls and reduces the possibility of attack from a prowler hiding nearby.