Instant hit item if you can build this

A device that keeps a distance between a kid and the TV. All kids ignore "Don't stand too close to the TV" when their favorite show is on.

Here is an idea: you give your kid a cool watch with a device inside that calculates distance between it and the TV. It turns TV automatically OFF if the kid is too close. Back off? turn the TV back on.

If GPS devices can be made, this technically should be a piece of cake. Unfortunately I don't have a clue how to create something that sends infrared signal to TV. Perhaps it can be integrated to xbox or something, that is connected to a TV and has a sensor...

Every parent in the world would want this watch+sensor device. This can be an instant hit.... get it patented... sell a ton of these and collect $. (dream on)