PIR Motion Detectors Do the windows work? If I mount a PIR (passive infrared) detector behind a window, pick up the movement of the other side of the window?
Two ways to answer your question.
1. A more theoretical approach.
a. Find a spectral response curve of PIR. I looked on the web and found this: ... http://www.murata.com/products/catalog/p (table top of page 9). It seems that the spectral response of the instrument is governed by the filter.
b. Find a spectral response curve of the glass. It depends on the formulation of glass.
C. If there is a band in the spectrum where both glass and the PIR will both have a good response (ie glass can assume that the electromagnetic waves at certain frequency and the PIR sensor can detect) , then the motion sensor works through the glass. However, my hunch is that the normal window glass to block the thermal infrared frequency.
2. experimental approach
a. Take a piece of glass and a PIR sensor. See if you detect through glass.
Posted on June 11, 2010.
