Preserve last calibration results between reboots

[gorbunovav]

Is your feature request related to a problem? Please describe.

The calibration process requires some stable and predictable conditions.
The auto-calibration feature is useful since it allows to simplify the sensor setup.
Periodical re-calibration makes sense to adjust expectations to the changing environment.
Automatic re-calibration on boot is unpredictable.

Describe the solution you'd like

Preserve calibration results in some way. And don't perform automatic calibration on boot if data already present.
Re-calibration can be performed on schedule via the exposed service.

Describe alternatives you've considered

Use manual calibration (e.g. turn-on automatic method, grab values, fill into config).
Downsides:

• each time sensor boots with some default values unrelated to the latest calibration results
• more manual work

[CarsonF]

I'll work on this. It goes hand in hand with the sensors refactor I'm about to start.

[Lyr3x]

@CarsonF This should be an optional configuration option.

[CarsonF]

This should be an optional configuration option.

As in not the default functionality?

[Lyr3x]

Yes the default should be false because i know that it can cause problems. Thresholds change by a lot depending on the sunlight and temperature. If you dont recalibrate for quite some time you getting worse results.

[CarsonF]

That makes this the opposite of #58 then. Maybe we should discuss more.

[Lyr3x]

I have #58 in mind and really want to implement that soon because this eliminates the frequent recalibration issue.

If #58 is done we this feature here can be default: true

[gorbunovav]

@Lyr3x but this feature only prevents the re-calibration on boot. So in the described scenario disabling it will only help if you are rebooting the device regularly.
Although I agree that it can be configurable.

[Lyr3x]

I think most of the users do reboot frequently to update the firmware and use the chance to get fresh thresholds in. I do understand why some don't want to do that always though 👍