How do PIR (passive infrared) motion sensors work?

How do ghost hunters use motion sensors?

SJGR uses Passive Infrared Motion Sensors (PIR). The sensor does not send out any kind of beam.  It is just a receiver.   It receives the Infrared Heat Signatures s coverage area.   Everything that is above absolute zero degrees gives off an Infrared Heat Signature.  Generally, the larger the object, the larger the IR Heat Signature from that object.   Most PIR Motion Sensors are set to ignore small things to help them avoid getting false alarms from small animals, bugs, etc.  The sensors have two settings on them, alarm and chime.   We usually use the chime mode which will set off an alarm that rings for a few seconds when it detects movement and then the sensor resets itself.   The alarm mode will sound a constant ringing that will not shut off until someone turns the sensor off.   The alarm mode can be used on unoccupied floors or areas so you will know that
something moved in that area when you return.  When a PIR Motion Sensor t anything visible moving, you have a major unexplainable paranormal event.



Helpful tips:

Some brands of sensors have 10 to 30 second delays when you first turn them on.

Watch out for mirrors, sometimes they can extend a sensors coverage area around a corner.

When you set off a motion sensor yourself make sure you announce it is a false alarm