Data Sheet

Did It Move? Detecting Motion with PIR +

Arduino

Wednesday, June 8

, 2011

if anyone is having troubles with a PIR sensor you got from SparkFun please keep in mind:

“The colors of the wires can vary greatly. Looking at the unit from the top, the middle wire is ground, the

left-most wire is the alarm, and the right-most is the power.”

Security alarms, time lapse cameras, and those house-lights that turn on when you walk by all have something in

common… Motion detection. Motion detection can be a very handy thing in installation art, interactive walls, and other

times you need a cheep way to know when people are around.

PIR or Passive Infrared is a common method of motion detection that measure changes in heat to signal the change. The

basic model is that they take IR (heat) images on 2 sensors at different times, when they differ, they know something has

changed. This particular sensor from SparkFun beings the signal pin low when it senses a change.

Hooking it up

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Did It Move? Detecting Motion with PIR + Arduino th Wednesday, June 8 , 2011 if anyone is having troubles with a PIR sensor you got from SparkFun please keep in mind: “The colors of the wires can vary greatly. Looking at the unit from the top, the middle wire is ground, the left-most wire is the alarm, and the right-most is the power.” Security alarms, time lapse cameras, and those house-lights that turn on when you walk by all have something in common… Motion detection.
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Hooking one up to your Arduino is pretty simple, but you need to make sure not to fall for the manufacturer’s trap. The red wire is V+ as you would think, the brown wire is ground, NOT the black wire. The black wire is the signal wire. To make matters even worse, the manufacturer uses a B/W image to show you what wire is what. Aside from power, the signal pin connects to any digital pin on your Arduino but also needs a 10k pullup resistor between the signal and 5V.
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