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iSpindel gravity correction on cold crash.

Open MonTage69 opened this issue 4 years ago • 10 comments

Noticed that when cold crashing the gravity goes up. 20C = 1.011 2.5C = 1.020

Maybe this is purely on the iSpindel side.

Pretty sure my calibration was done correctly as it's always been pretty spot on on my manual readings within 0.001 of a point.

I know the tilt is able to adjust.

Any pointers?

MonTage69 avatar Jan 12 '21 23:01 MonTage69

The iSpindel only transmits angle - not gravity - so there is no "temperature correction factor" applied on the device.

It's not a bad idea to build functionality into Fermentrack to apply a temperature correction factor. I'll use this issue to track against that feature.

thorrak avatar Jan 15 '21 04:01 thorrak

Thanks @thorrak

MonTage69 avatar Jan 15 '21 04:01 MonTage69

@thorrak iSpindel sends both a gravity (calculated using user input polynomial) and a raw tilt(angle) for all the supported services. Try to lookup for gravity var in received data.

@MonTage69

pppedrillo avatar Jan 27 '21 09:01 pppedrillo

It's not a bad idea to build functionality into Fermentrack to apply a temperature correction factor. I'll use this issue to track against that feature.

FYI iSpindel will soon have its own ATC functionality, but it will be optional (eg can be turned on or off).

pppedrillo avatar Jan 27 '21 09:01 pppedrillo

Agree, should just be optional

MonTage69 avatar Jan 27 '21 10:01 MonTage69

I didn't spot this earlier in either Fermentrack or iSpindel so even though a bit late to the party. Having temperature correction factor applied to SG would be a good thing, if the correction is best being applied by the iSpindel or in Fermentrack is debatable.

Looks as if the ATC feature hasn't got enough support in the iSpindel community though. If that's the case Temperature Correction applied in Fermentrack?

ChrisThomas42 avatar Feb 24 '21 17:02 ChrisThomas42

Looks as if the ATC feature hasn't got enough support in the iSpindel community though.

@ChrisThomas42 Not community. By some reason it basically has got no go from iSpindel project owner. But so far looks like Fermentrack has the same level of interest to this feature :)

pppedrillo avatar Feb 24 '21 18:02 pppedrillo

Looks as if the ATC feature hasn't got enough support in the iSpindel community though.

@ChrisThomas42 Not community. By some reason it basically had no go from iSpindel project owner. But so far looks like Fermentrack has the same level of interest to this feature :)

I mean... If someone wants to implement it, we can always add a flag to the iSpindel model to selectively apply it. The pull request button is at the top of your screen. ;)

The interest is implicit in the fact that there's an issue open against it, it just unfortunately isn't something I've yet had time to dive into.

thorrak avatar Feb 24 '21 18:02 thorrak

Looks as if the ATC feature hasn't got enough support in the iSpindel community though.

@ChrisThomas42 Not community. By some reason it basically has got no go from iSpindel project owner. But so far looks like Fermentrack has the same level of interest to this feature :)

By community I meant the wider user community, sorry. I was hoping that posting about this feature on UK and USA Homebrew forums it would spark a bit of interest. In 24 hours, across both forums only 3 yes's!

ChrisThomas42 avatar Feb 24 '21 20:02 ChrisThomas42

Per this site the formula for this appears to be the following:

Hydrometer Temperature Correction Formula

CG = corrected gravity MG = measured gravity TR = temperature at time of reading TC = calibration temperature of hydrometer

CG = MG * ((1.00130346 – 0.000134722124 * TR + 0.00000204052596 * TR – 0.00000000232820948 * TR) / (1.00130346 – 0.000134722124 * TC + 0.00000204052596 * TC – 0.00000000232820948 * TC))

thorrak avatar Jul 04 '23 02:07 thorrak