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Supergiovane / node-red-contrib-knx-ultimate

Control your KNX intallation via Node-Red! A bunch of KNX nodes, with integrated Philips HUE control and ETS group address importer.
https://youtu.be/egRbR_KwP9I
MIT License
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Datapoint 9.002 with direct kelvin input. #283

Closed Supergiovane closed 12 months ago

Supergiovane commented 1 year ago 
          That's very kind of you, but I had some spare time tonight and had another look at the figures I put into the Excel sheet.

It seems to be pretty simple: 1000000 / Mirek value = Kelvin-value That's no scientific formula I guess, but it's pretty precise within the usual range and is very similar to the values from ISE HUE.

I can use a simple function node to rescale your values to Mirek and convert to/from Kelvin, so it does not need to be done inside the node. If you like the idea you can put it there of course as DPT 9.002

(Btw. I never found a satisfying conversion from RGB to color temperature or vice versa.)

Originally posted by @SmartyKNX in https://github.com/Supergiovane/node-red-contrib-knx-ultimate/issues/281#issuecomment-1793862555

Supergiovane commented 1 year ago

Next version will be out shortly with dpt 9.002

SmartyKNX commented 1 year ago

I tried the new version last weekend and the values are a little bit out of my expectations.

Using the HUE app and selecting the center of the total range results in values of 4300K. I think this value is way to blueish for the actual impression from the HUE light.

Before you implemented this function, I took the 7.600 DPT with values from 0-65k and rescaled these values to the mirek-range from 153-500. 1000000/MirekValue results in pretty reasonable kelvin values. However these values are not the values I get, when using the direct output of your 9.002DPT.

Of course if you are happy with values keep them, because I can use my own conversion in Node Red anyway.

Supergiovane commented 12 months ago

Hi just to le you know, i'm working to fix the datapoint 7.600

Supergiovane commented 12 months ago

Hi node-red-contrib-knx-ultimate@2.2.33 is out with fixed conversion from 7600 to mired and vice versa. Thank you for point me out that.