OH3: RGBCW LED bulbs, which are the right item types for which channel?

  • openHabian 3.4.3 on rPi4 with 4GB

I seem to struggle with which item type to attahc to which channel for RGBCW lights.

I have a 1200x300 CW LED which has a:

  • colour temperature channel (dimmer type)
    • linked to a dimmer type item to change from cold to warm
  • level control channel, linked to a
    • dimmer type to change brightness, and
    • switch type

This works nicely.

Now I installed a RGBCW bulb, which I have set-up like this:

  • colour temperature channel (dimmer type) (#1)
    • linked to a color type to change from cold to warm
  • color channel (type color) linked to a
    • color type which provides the three HSB sliders (#2)
    • dimmer type to change the brightness (#3)

This also works, but shows the following problem:

I can use #1 to change CW
I can use #3 to dim CW
When I use #2 I can change colour and brightness, but when using the #1, it does not change the colour of the bulb; I have to go back to #2 to set H and S to 0 and B to what I had before.

Either I am doubling up on items, or have the wrong ones associated withe wrong channels.

What I’d like to achieve is, that I can set all CW-capable lights to the same colour temperature based on an ambient lux value… and control RGB colour via different rules, w/o touching/changing the CW LEDs…

That is, if this combination is possible at all.

Any hints appreciated.

I don’t use Color bulbs so this is strictly based on what I’ve seen. Usually the color temperature is linked to a Dimmer Item. The Channel says it wants a Dimmer Item.

Why would it. Color Items treat PercentType commands (i.e. the commands that come from a Dimmer Channel) as a command to change brightness. The color temp is a wholly separate control from the HSB. It should be linked to a Dimmer type Item.

Hmm, I removed the color item type from the ‘color temperature’ channel and added a dimmer. It (still) works.


However, I am still not clear on what items the colour channel needs. What I have got ATM is:


The Shed dining dimmer also affects the Shed Dining control (HSB). In the image we see B = Dimmer value.

Does this mean that if I want to switch the bulb OFF, I also need a switch item, in order to retain set colour temp and B values? To answer my question: it seems ‘yes’ (just added a switch).

However, it seems that in order to keep the CT dimmer value, I also need to ensure I set the HSB to 0,0,n, with n being the dimmer value


Does this set-up seem to be the correct one?

The issue is, if I have selected a colour and want to go back to CT only, I also have to change the colour back to 0,0,n (with n being the new|old|previous (before colour) value?!

With the current setup, if I add colour, setting H and S to 0 doe snot give me the CT function back. I also have to set the value for colour temperature. (which seems overly complex or my config is wrong).
Or my expectation is wrong. I am expecting that if I have a HSB control, it would be separate and in addition to the CT control.

Or should the dimmer for brightness in the colour channel be linked to the CT channel? As one could say why have a HSB and a dimmer control in the same channel, when B in HSB is the what the dedicated dimmer does. but then I have two dimmer in the CT channel. How does it know the difference, as in which is which?

Or do I even have to add a switch to the CT channel (and the dimmer item), meaning having three controls fo rthe CT channel.

It would be good to also hear from fellow peers who have their RGBCT lights working and more so controlled properly. (Whatever properly means). Again, I may be confused or overthinking this topic entirely.

To explain where I’m coming from: I have this pure CT light, where I set the CT value (linked item not shown in image) to say 80; here the dimmer to 9, and the ON|OFF switch, which will either switch OFF to come back with the same CT and dimmer values when switch on.


No. You can do it that way but it’s unnecessary.

IIRC you are still using Sitemaps. In that case link one Color Item to the Color channel of the Thing. On the sitemap, you can use a Color, Dimmer, or Switch element on that same Color Item and control it’s color, brightness or on/off. Three sitemap elements, one Item.

Color Temperature is a separate and independent Channel. That one you’ll want to link to a completely separate Dimmer Item and put on your sitemap as a Dimmer element.

Channel Item Element Controls
Color Color Color HSB values directly
Color Color Dimmer Brightness of light only
Color Color Switch ON/OFF state of the light only
Color Temp Dimmer Dimmer HS values of the light based on Dimmer value

In the Color Temp case, it makes no sense to send ON/OFF commands to it unless you want a way to jump to 0 and 100 (and what ever degrees K that represents).

I’m not certain how else to say it except you need to treat the Color and Color temp Channels as completely separate and independent from each other, at least when it comes to linking them to Items and sending commands to the light. So you will have exactly two Items, no fewer than two control elements on your sitemap and up to four control elements, three for the Color Item and one for the Color Temp Item.

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Yes, agree, and how I understood it.

Thank you for your clarification.
I thought I clarify this, before diving into installing more of these; (and potentially having to redo these).

The only difference I still is, that my pure CT light can be switched ON|OFF, retaining its CT and dimmer value, while the RGBCT does not. Switching the color channel OFF (say at 70%) and switching it back ON will start with a dimmer (brightness) value of 100.

WRT the sitemap; I like this idea, as it is saving on items.

Now off topic: did I read somewhere that sitemaps are kept (legacy) but are or not further promoted? E.g., people use HABpanel instead?!

Some lights remember, others do not.

No and in fact there are several new additions to sitemaps in OH 4 (a new input widget and support for other than OH default icons).

It is true though that only a minority of users continue to use sitemaps and even fewer use HABPanel which could be considered legacy. Most are using MainUI.

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