Here is an automatic cat brush with a smart sensor that detects when your cat approaches to start and select the right rotation direction. This cat brush is suitable for short and long coat. It is smart enough to stop when you try to hold it. The Groomatic has a detection range of 5 inches.
You can mount the Groomatic cat brush anywhere. It measures 5.9″ x 3.9″. You can find out more about it here.