Connecting an analog audio system to a local area network? Perfectly possible! This device not only controls powering the gear up and down sequentially, but also acts as a NAS for keeping my music collection and as a networked audio interface accessible with JACK, PulseAudio or Pipewire.
Hardware overview at https://www.youtube.com/watch?v=9gQRWPwGzJM
After a system crash the SBC didn't boot up and I had to install a new version of Armbian from scratch, which brought a new problem: the libraries my software depended on were outdated and I had to rewrite the software using libgpio. It was a good thing, because in the meantime I got a Home Assistant setup up and running, so I decided to ditch the crappy web interface and use MQTT for sending commands and status updates. After some fighting I got it to run like I wanted - here's the code: https://github.com/keriszafir/hifipower