Does this already exist?

Is there anywhere to find plans for this device: it is built for economy, durability and simplicty. It consists of an electric eye mounts near a cat litter box, and when triggered, sets up a timer. Cat just got in. Four minutes later, it triggers timed activity. Small electric desk fan goes on and runs a few minutes. Also, some kind of spray bottle puts scent into the air. Hmmm. While we are at it, a container of baking soda is triggered to dump a measured sprinkle over the box. Now, I’ve seen “Automatic empty” litterboxes that must work on similar principal, and it is AMAZING how incredibly outrageously overpriced expensive they are. There must be a better, cheaper way! This needs to be CHEAP and EASY…cat owners are already overpaying for vet bills, cat litter, cat food. WindowsLiveEvan at yahoo