My sister asked if I could build an automated chicken coop door for her. I started think of all the possible ways to make a door and how it should close. The easiest method is using a linear actuator. I also think it is the most reliable method. But I was looking at pulley systems and Guillotine coop doors. I was also looking at the ESP8266 for another WiFi project. But luckily, I found this smart garage controller on Amazon and it was under $30 and did all the WiFi and remote magic for me. All I had to do was make the controller was operating a real garage door. That's where the Arduino steps in. It simple will latch an output based on an input toggle. The garage door controller will short a connection for 2 seconds to toggle the garage door.
This is a smaller project, but something that would have taken a much larger effort 5 years ago.
I hope this project helps or gives an idea for someone looking to automate their chicken coop door.