Need a sensor that will detect a person, but not a cat.

I have a bunch of LED strips left over from other projects and would like to mount them under my bed frame, to be activated when my wife or I are getting in or out of bed. Trouble is - we have three cats, so an ultrasonic rangefinder - a fairly common way for me to do this sort of thing - would trigger every time a cat walked by.

I considered a far-infrared camera, since a person's foot would register high temperature and fur is a great insulator. Most of the time the fur would be low temp and could be lopped off by a threshold, but not always. At any rate, those cameras aren't cheap.

I have hardwood floors, so maybe I could put a rug down and put pressure sensors under that. The nice thing about hardwood floors, though, is that cleaning up cat hairballs is much easier. A rug would complicate that. Maybe a pressure sensor between the mattress and the box spring, or between the box spring and the bed frame?

Any thoughts?


The Grid-Eye sensor is a cheap, 8x8 pixel thermal camera, and can distinguish the size of heat sources.

Have you tried a PIR sensor, the sensitivity possibly could be adjusted to your needs. Of course closing the door when they are not in the room may solve the problem completely and much more cost effective:-)

Could you manage to lift a finger and put it on a button on your bedside table? A touch sensitive button of course, so no muscular effort is required. :slight_smile:

RFID tag on cat, RFID reader(s) on bed. If thermal triggered and tag sensed, is cat, ignore.

Weight sensor - easiest is FSRs under the legs of the bed. The moment you or your wife get off the bed, the weight reduces drastically and much more than even three cats jumping off at the exact same time.

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Or a beam-break sensor above cat tail height.