YES! I saw in a magazine those sensor dog doors! They're SO cool and I definitely thought about getting one (still may very well do that someday). They're expensive, so I'll have to save up. But I agree, that IS an excellent solution to only permitting certain animals to get through the door. Lol, although I could see the cats waiting there by the door, waiting for the dog to come, then going out literally with him. Lol. Cat's ARE smart, that's for sure. But that sensored door seems to be the best thing. Thanks!