Control a Garage Door with a raspberry pi and a relay board.
Using the hardware setup described in this Raspberry Pi Garage Door Opener instructable
This golang project produces a single binary that will host a very simple HTML web-app (with iphone icon meta) with a button and an endpoint you can HTTP GET to trigger the GPIO pin.
This project is the actual source code for the golang binary, which can be cross-compiled.
I maintain a bitbake layer that can be used to produce a purpose-built embedded linux image. If you're new to building an embedded linux project, this is a great one to start with!
The Quick Build Instructions in my bitbake layer should set you on the right path.