What would the PIR most effectively detect?

What would the PIR most effectively detect?

• A. Sound
• B. Cross walk
• C. Temperature change
• D. Light flicker

Answer: (B)

PIR sensors detect infrared energy emitted by warm objects and respond to changes in that energy in their field of view. Because a moving person or animal creates a changing heat pattern as they pass through the sensor’s area, a PIR is most effective at detecting someone crossing a space, like a crosswalk. Sound requires a microphone, not a PIR. Temperature changes in the environment don’t produce the kind of dynamic infrared energy change a moving body does, so they’re not what the PIR is designed to pick up. Light flicker is monitored by a photodetector, not a PIR.

PIR sensors detect infrared energy emitted by warm objects and respond to changes in that energy in their field of view. Because a moving person or animal creates a changing heat pattern as they pass through the sensor’s area, a PIR is most effective at detecting someone crossing a space, like a crosswalk.

Sound requires a microphone, not a PIR. Temperature changes in the environment don’t produce the kind of dynamic infrared energy change a moving body does, so they’re not what the PIR is designed to pick up. Light flicker is monitored by a photodetector, not a PIR.