Over at my other blog, I have been posting examples of wildlife photos taken with game cameras (a/k/a scout cameras or camera traps).
Seeking to learn more about how their passive infrared (PIR) detectors work, I was browsing the Web and ended up with South Jersey Ghost Research.
Apparently, PIR motion sensors can be used for ghost-hunting. Here is a tutorial, using the term loosely.
For instance, their diagram makes no sense. An animal as small as a mouse can trip a camera. I have seen it happen. Squirrels definitely will do so. And as for cats, what is in the lower right corner of the PIR-activated camera photo on this page at the Ghosthunter Store site?
Nevertheless, the Ghosthunter Store site confidently proclaims, “When a PIR Motion Sensor detects movement in an area where there isn’t anything visible moving, you have a major unexplainable paranormal event.”
(Unless something did move but was not captured due to digital shutter lag, which happens all the time, particularly in less-fancy cameras.)
Except … I thought that ghosts traditionally were associated with unexplained cold spots in buildings. When did they start emitting infrared radiation?
Clearly, I am not up-to-date on twenty-first century ghost-hunting.