Looking for a sensor that can possibly be tracked by motion sensor or some other sensor. Does that exsist? Like if I have a motion sensor in each room and arrival sensor on my cat or kid I can know exactly where they are.
This is called micro location, once you get down to the room level. The short answer is that since all of the radiofrequency protocols pass through walls it turns out to be quite difficult to identify a room from the room right next to it. Or even the room right above it. It almost always requires triangulation by at least three devices per room for the triangulation, plus one for the identification of the individual , and all that tends to get more expensive than most people want to do.
So you could do it, in the same way that high-security facilities do, but it’s going to cost a lot and there’s no easy way to plug that into SmartThings.
So everybody expects this to arrive eventually, but the low-cost solution just isn’t here yet.
You can find more discussion in the following thread (this is a clickable link)