Passive Infra-Red Sensor

I familiarized myself (and made a test) with a PIR motion sensor as a part of a course at Haaga-Helia held by Tero Karvinen:

I found a site with instructions of how to use the motionsensor to blink a led

I got the PIR and a led hooked to my arduino following the instructions, they also provided an example code to use. My only problem now seems to be how to test the sensor with all the movement around me in the class room.


I am using a box to let the PIR calibrate.

Didn’t really notice a difference.


There was a jumper setting under PIR with L and H setting
by default it was set to H. I swiched it to L and tested again.

Now it seems to work as intended.

Symbol H: Output remains HIGH when sensor is retriggered repeatedly. Output is LOW when idle (not triggered).

Symbol L: Output goes HIGH then LOW when triggered. Continuous motion results in repeated HIGH/LOW pulses. Output is LOW when idle.

more information can be found on the PIR sensors pdf at parallax’s website

and more directly:


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