PIR Sensors

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PIR Sensors Info

Pyroelectric devices, such as the PIR sensor, have elements made of a crystalline material that generates 
an electric charge when exposed to infrared radiation.  The changes in the amount of infrared striking the 
element change the voltages generated, which are measured by an on-board amplifier.  The device 
contains a special filter called a Fresnel lens, which focuses the infrared signals onto the element. As the 
ambient infrared signals change rapidly, the on-board amplifier trips the output to indicate motion.

--From the PIRSensor-V1.1 pdf (linked below)

PIR Sensor Datasheets

pdf warning!

File:PIR Sensor 2 Element Datasheet.pdf

Schematics for PIR motion sensor boards

Hundreds of circuit boards incorporating PIR motion sensors were donated to Noisebridge. They are available for use immediately, and they are currently located in the storage area of the 83c Mezzanine. There's a page for the schematics of these PIR motion sensor boards

There's also a pdf of the same schematics at: File:PIR SensorBoardSchematic.pdf
and an LTspice schematic of the sensor front end circuit: File:PIR review 001.doc (needs some extraction and installation)

03.PIR Cellphone Board2.png PIR-less motion sensor board (see G101 for PIR placement location)

02 PIR Cell.png Backside of PIR motion sensor board

On 4/7/09 I hooked up a scope to the sensor output (pin 8 on the PIC) and 12V on the power input (marked [P5], next to LED, polarity on bottom silkscreen) , and got lovely +5 logic high signal by waving my hand over the sensor, 300-400 ms long. These units are ready to rock! Jtfoote 15:45, 7 April 2009 (PDT)

Brainstorm ideas for projects incorporating this large number of boards and sensors:

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