LitterMaid LM900 self-cleaning cat litter box works best with premium clay based cat litter. Your cat must be in front of the sensor for 5 seconds then it will automatically cycle 10 minutes after your cat leaves the litter box, raking the waste into a disposable container, where it and odors are sealed away.

Amazon.com Review 

Ideal for a household with a large cat or more than one cat, this big, self-cleaning litter box eliminates most odors while keeping the litter pleasingly fresh for tabby. It's ingenious in design: a cat entering the box triggers a sensor; the sensor sets a timer that counts off 10 minutes; then a rake runs through the litter, scooping out clumps and depositing them in a plastic container at the box's end; the container is automatically sealed until the next cat visit, when the raking cycle opens the container for another deposit. (Twelve reusable, disposable containers are included, each 13 inches long, 4 inches wide, and 3-1/2 inches deep.) The litter box can be plugged into a wall socket (AC adapter included) or operated on eight D-cell batteries (not included). It comes with a durable carpeted ramp that leads a cat into the box and cleans its paws on the way out. For safety, the rake stops and reverses at the slightest touch if an object gets in the way. If a cat re-enters the box before the initial 10 minutes have elapsed, the timer automatically resets. The litter box is made of hard plastic and measures 29 inches long, 8-7/8 inches high, and 16-3/4 inches wide. For proper operation, it requires premium, clumping litter but does not need as much as a nonautomated litter box of the same size. For cleaning, the litter tray can be detached. Instructions for acclimating a cat to the box are included. --Fred Brack