Get correct color temperature from CCT LED-Controller

Configuration Zigbee
1

Hey guys,

I just wanted to get the most out of circadian lighting so I installed some Gledopto GL-C-006P CCT LED-Controller together with 2200K-4000K WW/CW LED-Strips in my kitchen.

Here’s my Problem: If I look at the Gledopto’s State attributes it reads min_mireds 158 (6300K) and max_mireds 495 (2000K).
While the attached lightstrip is only 2200K min and 4000K max I can’t pair them with e.g. hue bulbs (2200K-6500K) because the temperature is way off.

At 166 mireds (6000K) set with light.turn_on the hue bulbs are at exact that value but the lightstrip doesn’t even hit it’s max of 4000K because the lowest value on the controller is 158.

Then I thought I could simply customize the controller entity so that min_mireds is 254 (4000K) and max_mireds is 454 (2200K). The customization works but then with light.turn_on set to 254 the controller doesn’t translate that to “go to the maximum on the colder end” and instead sets itself to what it’s told: 254.
So I have the same issue like before but am unable to get to the ends of the controller’s spectrum.

I hope it’s not too confusing to understand and hopefully someone can help me how to tell the controller that full brightness on the cw-channel represents 4000K and full brightness on the ww-channel is 2200K.

Regards
Stephan

2

Stephan,
I ran into this same problem. I had to write a script that computed the correct (closest) setting for the strip. Then instead of calling light.turn_on with that temperature, I have to call the script. I solved this by having a script that sets the color temperature for all lights except lights that end in “_no_ct”. Those ones get handled differently, and, in the case of my GL-C-006P, the script does the computation and sets the appropriate temperature.

Here’s the core of the script I used:

    - service: light.turn_on
      data:
        entity_id: light.living_room_white_led_strip_no_ct
        color_temp: >
          {% set req=states('input_select.global_color_temp_k')|int %}
          {% set min_req=2700 %}
          {% set max_req=4000 %}   
          {% set min_needed=2020 %}
          {% set max_needed=2995 %}
          {% set per_K = (max_needed-min_needed)/(max_req-min_req) %}
          {% set scaled = (req-min_req)*per_K+min_needed %}
          {{(1000000/scaled)|int}}
        transition: 10
3

Hi David,

thanks for your help, I really appreciate that! Could you explain to me, how exactly the core of your script works? I can’t figure that out.

And would it be possible to create a dummy-light with Template Light that has the range from 2200-4000K and triggers the original light with computed values?

That would be helpful, because I could use that dummy in adaptive lighting custom component.

4

If you mean the script above (as opposed to the main script that sets the color temperature for all lights) it works as follows:

{% set req=states('input_select.global_color_temp_k')|int %}

This makes a variable called req that is equal to an input_select (a pop-up menu in the GUI) called “global_color_temp_k” converted to an integer “|int”. This variable is used later in the computation.

The next four lines set some variables. The idea is to do a linear scaling between the input range and the output range with an offset (min_needed) for the minimum value. This is a mess because I tried to do it based on first principles, but the calibration is wrong so I had to address min_needed and max_needed to make the ranges look good.

The sixth line is computing a scale factor “per_K”
The seventh line is applying the scale factor and the offset to the input value “req” to get the final Kelvin value “scaled”.
The last line:

{{(1000000/scaled)|int}}

Is returning the color temperature in mireds. (I wrote this script before HA supported Kelvin directly.

I’m sorry that’s not very clean. To use the formula you put in the min/max values for min_req and max_req from your strip and then you adjust the min_needed and max_needed so the colors look right. (Or at least that’s what I did. :slight_smile:

-David

1 Like
5

I know it is two years later, but I found this post because I had a similar issue. Hopefully my solution can help others who still find this thread.
I fixed it with a template light in the configuration.yaml. It is a little hassle to set up, however, it works reliably and effortless after it is implemented. Just use your new ‘scaled’ light.
My example is below:

light:
  - platform: template
    lights:
      example_light_scaled:
        friendly_name: "Example Light Scaled"
        value_template: "{{ states('light.example_light') }}"
        level_template: "{{ state_attr('light.example_light', 'brightness') | int }}"
        min_mireds_template: 158
        max_mireds_template: 370
        temperature_template: "{{ ((state_attr('light.example_light', 'color_temp') | float - 158.0) / (495.0 - 158.0 )* (370.0 - 158.0) + 158.0) | int }}"
        turn_on:
          service: light.turn_on
          target:
            entity_id: light.example_light
        turn_off:
          service: light.turn_off
          target:
            entity_id: light.example_light
        set_level:
          service: light.turn_on
          target:
            entity_id: light.example_light
          data:
            brightness: "{{ brightness }}"
        set_temperature:
          service: light.turn_on
          target:
            entity_id: light.example_light
          data:
            color_temp: "{{ ((color_temp | float - 158.0) / (370.0 - 158.0 )* (495.0 - 158.0) + 158.0 ) | int }}"
        supports_transition_template: "{{ true }}"

In my example I wanted to convert from a range of 158 till 495 (6330K - 2020K, Gledopto GL-C-006P CCT LED-Controller), to a range of 158 to 370 (6300K - 2700K, my CCT LED-strip). I did not shorten the calculations above, so the conversion is human readable and easily editable.
I did not implement effects, since I don’t need those anyways.