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Want to learn how to hook up a passive infrared (PIR) sensor to your Arduino? Check out this video I put together doing just that. These sensors are very nice to work with either by themselves (along with a transistor or relay) or on a microcontroller. You get about a 20 ft. range for detecting motion from humans, animals, other things that emit a decent amount of infrared radiation. WILL NOT DETECT THE UNDEAD.

This is the same alarm setup I used to prank my kids on April Fools’ Day.

In the Maker Shed:

mz inthemakershed 5 John Park in the Maker Shed: PIR Arduino motion alarm

The PIR Sensor detects motion up to 20 feet away by using a Fresnel lens and infrared-sensitive element to detect changing patterns of passive infrared emitted by objects in its vicinity. Inexpensive and easy to use, it’s ideal for alarm systems, motion-activated lighting, holiday props, and robotics applications.


  • Simple 3-pin connection
  • Single bit output
  • Small size – easy to conceal ( 0.96 x 1.0 x 1.27 in.)
  • Arduino Compatible


PIR Sensor

John Edgar Park

John Edgar Park likes to make things and tell people about it. He works in CG animation at DisneyToon Studios and writes for Make, Boing Boing, and other places online and in print. You can find him at and twitter @johnedgarpark — if you like that sort of thing.

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