Honestly if they are not that technical, I’d with the nearly fool proof solutions of QNAP and Synology and alike. It is very easy to maintain. I think e.g. Synology still provides updates for their 2012-2013 generation devices, hardware limitations apply whatsoever.

Surely you get less Hardware/Dollar but the software is near fool proof. I recommended such devices to two of my half technical friends and granted mutual space for encrypted off-site Backups and it just works flawlessly. If they would have me setup any self made raspberry pi like solution and anything goes wrong with their data I’d rather not stand in their line of sight.

is the history of the values available after restart? like the graphs shown when you click a sensor entity?

recorder is enabled by default. however, when you are using docker it might be possible that the default file data base (it’s folder) is not mapped to a persistent location outside the container (resp. in the host file system).

however, I really do not know much about all this docker related stuff. my recorder suggestion was just a shot into the blue. if I would be facing this problem I might just try to set up a relational data base like MySQL or PostgreSQL as a target for the recorder.

Restoring the states depends on the recorder. What are your settings regarding the recorder?

Edit: reference https://www.home-assistant.io/integrations/recorder/

I know it’s different, but if I wouldn’t know home assistant I could have assumed it had something to do with USB

To be honest having an information about the actual percentage state of opening is actually useless anyway. I just need the information if it’s properly closed which could be achieved with a simple reed relay.

Having the sensor on the moving parts also comes with other challenges anyway. I used a cheap curly telephone cord to connect the sensor to the ESP8266 but it’s actually already worn out and thus hanging low when the door is open, as the normal state is that it is extended when the door closed

I installed an ultrasonic Sensor at the lowest segment of the garage door. It mostly does it’s job, though it is unreliable when the door is fully open, as the sensor tilts towards the open end and the distance is then too long. Also someone standing in the opening might block the sensor.