Add CCT LED support for Plus RGBW PM

[Bieniu]

Several users have reported to me that they cannot control the color temperature of CCT LEDs with the Plus RGBW PM. I think these are quite popular LEDs and the device should support them.

[Yakov]

Came here looking for an RGB+CCT controller. This will need to be a new product since CCT LEDs are basically two separate channels. I'll need to wait for Shelly to introduce such a product 😞

EDIT: while we are at it, I wish such a controller had some sort of a "raw" mode that allowed setting each of the five channels independently, with a 10-bit linear precision or greater. 8-bit is not enough. This is in contrast to many other controllers on the market that allow controlling either the whites or the RGBs, but not both at the same time.

Alternatively, it could have a CIE XYZ input plus a configurable color calibration matrix (XYZ coordinates of each of the RGBWW channels). The upside of this approach is that even non-CCT controllers could be controlled with the same API, producing the same colors. Things like arbitrary color-temperature would be easily achieved (e.g dim to red would be cool).

 

Edited September 26 by Yakov