A motion sensor, or motion detector is an electronic device that contains a physical trigger mechanism or
electronic sensor that quantifies motion. It can be either integrated with, or connected to, other electronic
devices that can alert the user of the presence of a moving object within the field of view, or magnetic
influence. They basically form the vital component of comprehensive security systems often used in homes
and businesses and adopted by paranormal groups for research and investigation.
An electronic motion detector contains a motion sensor that transforms a detection of motion into an electric
signal that can measure optical (visual) or acoustical (audio) changes in the field of view. Usually detecting
motion or sound up to 15–25 meters (50–80 feet) away.
There are basically five types of sensors used in motion detectors spectrum:
Active Infrared Motion Detector (IR) – Active infrared motion detectors use an IR sensor, as well as a
source of radiation. The sensor is able to detect interruptions in the radiation it receives from the
radiation source. This basically means that an IR motion detector is able to detect the signal of heat
energy emitted by an intruder as it differs from the constant infrared scanning activity of the detector, as
long as the intruder passes through it’s detection range.
Passive Infrared Sensors (PIR) – Currently the most popular type of motion detecting system. PIR
motion detectors are relatively inexpensive compared to detectors that utilize other technology. A PIR
sensor is able to use an optical collection system in combination with several different sensing
elements. This allows the sensor to detect any changes that occur in ambient infrared radiation. The
sensor is able to recognize a thermal infrared image (created by infrared technology combined with a
heat sensor), which usually starts the transmission of an alarm signal back to the unit’s receiver. If the
PIR sensor is connected to a monitored security system control panel, the control panel can interpret the
alarm signal, and convert it into data to trigger the appropriate alarm.
Ultrasonic Motion Detector (active) – An ultrasonic motion detector is able to use sound energy in
order to detect movement in a specific region. This ultrasonic sound energy is emitted in waves, which
come from quartz-crystal transducers. When the sensor detects movement, the sound waves are
disrupted, which triggers the sensor. Ultrasonic motion detectors are commonly used in automatic
doors, since they are reliable and easy to install. The main limitation of an ultrasonic motion detector is
that it can be blocked by any material, and can be easily disrupted.
Continuous Wave (Microwave active) – CW motion detectors use microwave signals to emit
frequencies to bounce off of the surrounding area (which is why they are sometimes referred to as
“microwave motion detectors”). The sensor is able to detect when there are subtle changes in these
frequencies, since this would signal a disruption. When an intruder passes the field of a CW microwave
sensor, he disrupts the frequency, which sets off the sensor’s alarm. CW motion detectors are generally
more expensive than PIR motion detectors. This is because they are highly sensitive, and are very
reliable over longer distances than other sensors.
Vibration Motion Detector - A motion detector that detects simple vibration can either be made from
materials at home, or purchased as an electrical device. Most vibration motion sensors use the
piezoelectric effect (the ability of some materials to generate an electric field) in order to detect motion.
Simple do-it-yourself vibration sensors most commonly use a lever that activates a switch when it
The principal methods we’re interested in, is detecting motion that can easily be electronically identified via
optical and/or acoustical detectors. Of which, infrared light or laser technology is most often used for optical
detection, while motion detection devices, use sensors that detect movement and send a signal to a an alarm
switch that usually produces a shrill sound that can be heard for great distances, or to an imaging device to
start recording audio and/or video.
Many high-end security cameras are motion detector equipped with the cameras connected to a computer
system (DVR - Digital Video Recorder) which in turn stores and manages the captured images to be viewed
at a later time or viewed over a computer network.
The chief application of course being security systems, usually designed to detect:
Detection of unauthorized entry,
Detection the cessation of occupancy of an area to extinguish lighting, or entry into a darkened area to
Detection of a moving object which triggers a camera to record subsequent events.
All of which can be used to detect and record paranormal activity.
The ITSPP Favorite
We are use a variety of Motion Sensors, but by far we prefer the 'broken beam' type of sensor. We use them
when we wish to secure a doorway, walkway, hallway, and even by our hidden camera equipment. These
sensors allow you to leave the room or area unmonitored, sending out a loud shrill when activated. Notifying
you of activity in the area, and is totally battery operated.
Wireless 2000 Driveway Alarm
Although the alarm is designed for driveways as an electronic monitoring system that automatically sounds
an alarm when a car pulls into the driveway. The fact that it's a portabile, self-contained, light weight and
simple to operate unit makes it a perfect addition to the ITSPP arsenal of detection equipment. The unit can
easily be attached to a doorway with Velcro strips. Then when the trigger is broken, it alarms an electronic
sensor that emits a loud pulsating alarm at the receiver up at the ‘home base’ monitoring area during an
investigation to 2000 feet away.
OPTEX now brings the benefits of its advanced wireless technology in the form of greater RF transmission
range with this Wireless 2000 entry announcer with a design versatility that makes it easy and convenient to
The system can be installed anywhere easily and quickly with no wiring, is fully battery operated and now
allows for a 2000 ft. line of sight transmission range. Add the additional range unit repeater for greater
coverage. The ideal choice for perimeter awareness and wireless remote control for the serious
Important to Note
We would also like to point out that it is our experience that ghosts, spirits, and entities will
rarely trip motion detectors. As our cameras have caught shadow figures moving freely in
and around our sensors with no effect. However, it is quite valuable in the detection of
hoaxes and fraud by the living. Thus, the motion sensor can help ensure your investigation is
valid fr and are therefore is a viable tools in your arsenal.
Caught in the Act
Ghost Hunting 101
The content of this website is the copyright of World Nexus Publications © 2008-2011