Motion Detector
Detecting Motion Where no one is Present

Ghost Hunting Equipment: Motion Detector
Detecting Motion Where no one is Present

A motion detector can be used to help aid the ghost hunter by detecting motion where no one is present. Motion detectors usually emit a loud sound to alert the person there is movement within a specific area and generally these devices only emit a sound when the object passing in front of the device is a specific size. Small cats and dogs generally do not set off a motion detector.

A motion detector is a device that contains a physical mechanism or electronic sensor that quantifies motion that can be either integrated with or connected to other devices that alert the user of the presence of a moving object within the field of view.

An electronic motion detector contains a motion sensor that transforms the detection of motion into an electric signal. This can be achieved by measuring optical or acoustical changes in the field of view. Most motion detectors can detect up to 15–25 meters (50–80 feet).

A motion detector may be connected to a burglar alarm that is used to alert the home owner or security service after it detects motion. Such a detector may also trigger a red light camera.

An occupancy sensor is a motion detector that is integrated with a timing device. It senses when motion has stopped for a specified time period in order to trigger a light extinguishing signal.

There are basically three types of sensors used in motion detectors spectrum:

  • Passive Infrared Sensors (PIR) - Looks for body heat. No energy is emitted from the sensor.
  • Ultrasonic (active) Sensor - Sends out pulses and measures the reflection off a moving object.
  • Microwave (active) Sensor - Sends out microwave pulses and measures the reflection off a moving object. Similar to a police radar gun.

Ghost Triggers Motion Detector?

Motion sensors at a gym in Kansas turned the security system on 9 times... and when the security videos were viewed, only a ghostly orb was captured roaming through the gym.

The most common motion detector for ghost hunting is usually the 'Passive infrared sensor' type but some ghost hunters use ultrasonic and microwave sensors as well or a combination of them.

The reason why passive infrared sensors or PIR are used the most is because they detect body heat and no energy is emitted from the sensor.

It is believed that some spirits when they attempt to manifest, create heat (energy) which in turn creates cold spots as well. This heat would then be picked up by the PIR detector.

Additionally, the fact that a PIR detector does not transmit energy from the sensor to detect movement is a bonus since the chances of the motion detector affecting or interfering with other equipment is low.

Many modern motion detectors use a combination of different technologies. These dual-technology detectors benefit with each type of sensor, and false alarms are reduced.

All companies have the option to use PIR/Microwave Motion Detectors that have "Pet-Immune" functions which allow the detector to ignore pets that weigh up to 36 kg (80 pounds).

Placement of the sensors can be strategically mounted so as to lessen the chance of pets errantly activating alarms.

Often, PIR technology will be paired with another model to maximize accuracy and reduce energy usage. PIR draws less energy than microwave detection, and so many sensors are calibrated so that when the PIR sensor is tripped, it activates a microwave sensor.

Most types of motion detectors are not able to ‘see’ through windows or walls.

False alarms are those usually caused by technical errors such as electrical and mechanical failures. Many false alarms can be caused by wind blown debris, animals, insects and foliage.

Sequencing alarm systems to trip the alert mechanism only when both alarm sensors have been activated will reduce nuisance alarms, but may also cause the probability of detection to decrease.