Colour temperature?

  • Hi,

    I need to send the correlated colour temperature (CCT) to the controller from a node. How can I present it please in MyMessage()/present()? It is expressed in Kelvins.

    FYG - Colour temperature defines the colour appearance of a white LED. CCT is defined in degrees Kelvin; a warm light is around 2700K, moving to neutral white at around 4000K, and to cool white, at 5000K or more.

  • You may use virtually any other type of sensor as a child (apart from the ones representing percentage values). I fyou want to have it bidirectional, use one your controller is able to send. In most cases S_CUSTOM is a good idea, but eg. FHEM will then provide you with 5 variables to exchange info between controller and node - that may be to much.

  • @rejoe2 I am not sure Domoticz would accept S_CUSTOM. It may have been changed recently though. But I wonder if anyone has had a similar issue. How to represent Kelvins? What's the best representative in MySensors?

  • Mod

    @alexsh1 I would try the options supported by S_LIGHT_LEVEL, and normal temperature and see which looks best in Domoticz.

    Alternatively, convert the temperature to a rgb value (algorithm: ) but I guess it depends on what you're going to do with the value.

    V_TEXT might be a viable fallback if nothing else works.

  • @mfalkvidd Nice one - thanks. The only issue is this:

    Start with a temperature, in Kelvin, somewhere between 1000 and 40000.  (Other values may work,
         but I can't make any promises about the quality of the algorithm's estimates above 40000 K.)

    I have values from 0 to 65535 on RGBW (Provides 16-bit resolution for each channel
    (R, G, B, W))

  • Mod

    @alexsh1 that's why I suggested the conversion. Or do you need values below 1000K/ above 40000K?

  • @mfalkvidd For now, I left it all in Lux. I have to think about what to do next. This is for VEML6040 - I intent to use it to manage RGBW LED colours behind my TV