Automatic Pet Door

My pet door attempt which worked for a while, involved two motion sensors (IR type), one on each side of the door, that were focused for the area right in front of the pet door. When they detected movement, they triggered the Arduino to open the door by raising it (small motion limited winch) and left it open for 7 seconds then slowly closed it. After closure there is a 10 second delay before next "alert" for motion. It worked perfectly for several days. I noticed the dogs were at first afraid of it. But, soon caught on to stand in just the right place to trigger the motion detector and then go through quickly. The cats were confused by it and thought it was a play thing. The problem was that cats sometimes just guard the door, or sit in front of it watching it go up and down. The dogs open it and if it is guarded by one of the cats, they just begin barking to try to move the cat. It was actually pretty hilarious and I regret not doing a video on it. I came to the conclusion it was not for our menagerie and took it down. But, the idea seemed to work well otherwise. I had not anticipated the unexpected animal reactions to it. Cats! As usual, they will require something "special".