Thank you for your suggestions! I’ve been tinkering with Find3 a bit but will look further into passive scanning, the active one requires an app on a phone which won’t work. For that reason Zanzito is also not an option.
Room Assistant might work as well, depending on how many PIs I’d need to cover the whole house. When I looked at RA last I couldn’t figure how it worked so I never tried it. There seems to be no learning involved so I don’t see how it could correctly know which room the user is. If I understand it correctly RA scans for BLE tags and measures their distance, relying on the room name the tag supplies to then deduct which room the tracked item is in, instead of having a learning mode like Find3. I’m afraid that this would makes it either less reliable or require more beacons (maybe even servers) to be able to detect transitions between rooms correctly.
Passive Find3 and RA are both worth a/another try though, thank you!