The door will look like this.
The door uses a motion sensor which is located 1 meter away from the door. When someone brakes the beam the doors open immediately. The person has 15 seconds to go through the door. If a leaf or something light breaks the beam it will still open. No matter how heavy something is it can go through anytime. The beam is 7 cm above ground. That means that no small creature can pass. The beam is 2 centimeters thick 
