I've been thinking of building an automated coop door closer. Can you link me to some more info on yours?
https://www.amazon.com/Automatic-Chicken-Coop-Door-Standard/...
It has a solar panel and rechargeable battery and you program in your lat/long and optional + or - times for the door to remain open or close around sunrise and sunset.
It works well. Of course, you could hack something up with a micro-controller to do the same thing rather easily.