Animal Detector

I forget, sometimes, what I designed in the past. I came across an interesting design of mine on the Internet this week. It is easy to detect a human, say, reaching out a hand for the front door, or stepping onto a doormat -- however, it is not so easy to do that with an animal. With passive detectors, that is. Therefore I induced currents in animals, and detected the electromagnetic radiation they emitted. That is an active detector. It was perfectly harmless to the animals, and solved the difficulty of detecting them. OBSERVATION: I would do it differently today, but the diagram gives one the idea.