I wanted to set up presence detection in Home Assistant without exposing my installation to the internet, and without giving the companion app on my phone access to location data.
I use MikroTik network gear at home, so I added the Mikrotik integration to Home Assistant. It showed my phone as a MAC address, connected through Wifi, and I used that as device tracker. Everything seemed fine, but then the next afternoon. the device tracker still showed me as Away.
I then discovered that GrapheneOS (edit: Android rather, see below) uses a different random MAC address for each connection to a network, as default. Changed it to use a static random MAC for my home network, and now it works as intended.
All this to avoid running the Morning Coffee automation if I'm not even home.
