SK6812 Warm White Channel Configuration

andpro792 · June 19, 2024, 4:10am

Hello! I’ve searched a bit for this and haven’t found a solid answer. Is there any way to make WLED calculate color temperature assuming that the W channel on a strip is a Warm White diode? As of now setting to a warm temperature results in it tinting the 3000K white led incorrectly. Thanks in advance for the help!

Magig_Wled · June 19, 2024, 4:32pm

welcome @andpro792 Hi
the Color Temp depends also on Stripe Voltige the SK6812 may not be the real controller on the LED only the Manufacter advice so its very hard to tell

the DEVES on Wled are working ona issue that targets this Color Differents even on other type stripes to get a per PIN correction Value

is it a REAL 5PIN LED Stripe

andpro792 · June 19, 2024, 4:56pm

Thanks for responding!

This is a 3 pin pixel map strip from superlightingled.com.

Seemingly setting the color temp colder somewhat rectifies the issue despite the strip being a bit more red/pink than a consumer LED product from Govee/Hue/LIFX. For reference 4200K on this strip looks like a LIFX 2700K, near identical but the SK6812 (so we think) product has a pinkish tone vs the more amber tone of the other.

Magig_Wled · June 21, 2024, 11:38am

This also depends higly on the Power
if you injekt multiple times like in a matrix the color Temp changes slightly

andpro792 · June 21, 2024, 5:03pm

Interesting. There’s only one injection point that I’ve found necessary when installing.

It’s about 6.45m of 12v tape. The color temp seems consistent across the strip.

So I understand: WLED knows that this strip is RGBWarmWhite (3000K) without me telling it? There were options for me to purchase a Natural or Cool White as well but I didn’t realize that it wasn’t an option to pick from on the WLED controller software.

kilrah · June 22, 2024, 7:36am

Ignore, he’s completely missed the question again.

The auto-white is pretty basic and doesn’t take color temp into account

github.com

Aircoookie/WLED/blob/main/wled00/bus_manager.cpp#L78


      
            uint8_t swapW = defaultColorOrder >> 4;
            for (uint8_t i = 0; i < _count; i++) {
              if (pix >= _mappings[i].start && pix < (_mappings[i].start + _mappings[i].len)) {
                return _mappings[i].colorOrder | (swapW << 4);
              }
            }
            return defaultColorOrder;
          }
          
          
          uint32_t Bus::autoWhiteCalc(uint32_t c) {
            uint8_t aWM = _autoWhiteMode;
            if (_gAWM != AW_GLOBAL_DISABLED) aWM = _gAWM;
            if (aWM == RGBW_MODE_MANUAL_ONLY) return c;
            uint8_t w = W(c);
            //ignore auto-white calculation if w>0 and mode DUAL (DUAL behaves as BRIGHTER if w==0)
            if (w > 0 && aWM == RGBW_MODE_DUAL) return c;
            uint8_t r = R(c);
            uint8_t g = G(c);
            uint8_t b = B(c);
            if (aWM == RGBW_MODE_MAX) return RGBW32(r, g, b, r > g ? (r > b ? r : b) : (g > b ? g : b)); // brightest RGB channel

blazoncek · June 23, 2024, 8:33am

WLED does not know about color temperature of LEDs.
What it does when you set “color temperature” is approximate perceived color temperature based on some common values. Those may not be accurate for a particular strip/LEDs.

If you are using a CCT strip (one having CW and WW LEDs) it will proportionally light up each of the LEDs according to temperature slider.

Auto white has nothing to do with color temperature.

andpro792 · June 24, 2024, 5:18pm

Thank you for this!

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SK6812 Warm White Channel Configuration

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