More "tell" than "show", but nonetheless something I enjoyed developing.
The brains of the system is a Raspberry Pi Zero W in a 3D-printed enclosure.
It is connected to four reed switches (two per garage door), through which it can determine if a garage door is (fully) open or closed. The relais are connected to the input of the door motors.
A little python script is running on the RasPi and providing an API via a flask-server. This allows querying the current state (open/closed/unknown) and controlling the garage door.
The typical use case is in conjunction with geofencing on a smartphone to automatically open/close the garage when arriving/leaving with the car.