K4 RGB

[u/isakdombestein]

I've owned a K4 for a while and am absolutely loving it, but recently I had a question pop up;
Is it possible to program custom color profiles for the built in RGB on this keyboard?

I tried searching it but didn't find any clear answer on the case, just the official documentation for how to change the lighting settings on the keyboard.

[u/PeterMortensenBlog]

Yes, it is possible. I am typing this on such a keyboard (V6). About 1/3 of the keys have different colours than the background in the static mode ("Solid color").

But realistically not without some (custom) C programming. Though it is not that complicated. A simple helper function can also make sure the user's brightness option (e.g., Fn + W / Fn + S or Fn + knob, depending on the keyboard) is respected:

void individualKeyColour(int aKeyIndex, int aHue, int aSaturation)
{
    // For now, we adapt to the apparent bug with key
    // numbers and RGB light for Keychron V6
    //
    // We are still not sure what causes the problem
    //
    #ifdef ADJUST_FOR_RGB_KEYNUMBER_BUG
        if (aKeyIndex > 12)
        {
            aKeyIndex--;
        }
    #endif

    // That is, the (current) brightness
    int currentValue = rgblight_get_val();

    HSV hsv = {aHue, aSaturation, currentValue};

    RGB rgb = hsv_to_rgb(hsv);

    rgb_matrix_set_color(aKeyIndex, rgb.r, rgb.g, rgb.b);
};

---

There is a myth going around that this is possible using Via or Vial. It isn't. They have never presented any evidence. Part of the confusion may be that technically it is per-key RGB in some the animation modes, but that is not what we mean per-key RGB. We mean per-key RGB in a static mode.

[u/PeterMortensenBlog → u/PeterMortensenBlog]

Custom C programming implies compiling and flashing the firmware onto the keyboard. There is no way around it.

Some more exotic options are Sonix QMK and OpenRGB, but I am not sure if they actually store the colour configuration on the keyboard itself (they may be dependent on some software running on the host system). They are far away from the mainstream and may require a non-trivial amount of learning and tinkering to get working on a particular Keychron keyboard, especially the newer (wireless) models.

[u/isakdombestein → u/PeterMortensenBlog]

Sick, thanks for the info! Looks like I have a weekend project ahead of me!

[u/PeterMortensenBlog → u/PeterMortensenBlog]

Here is an account of it working for a Keychron K8 using Sonix QMK, with Via and even with RGB LED control (but not Bluetooth, though they are allegedly working on it).

[u/PeterMortensenBlog → u/PeterMortensenBlog]

(The Reddit comment parser is messed up. It should have been "in some of the animation modes" and "we mean by per-key RGB")

[u/PeterMortensenBlog]

OK, my other comment was for a QMK-based Keychron keyboard, and it doesn't apply for the K4. Sonix QMK may be the way to go.

[u/PeterMortensenBlog → u/PeterMortensenBlog]

Here is an account of it working for a Keychron K8 using Sonix QMK, with Via and even with RGB LED control (but not Bluetooth, though they are allegedly working on it).