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RGB Underglow Configuration

See the RGB Underglow feature page for more details, including instructions for adding underglow support to a board.

See Configuration Overview for instructions on how to change these settings.

Kconfig

RGB underglow depends on Zephyr's LED strip driver, which provides additional Kconfig options.

Definition file: zmk/app/Kconfig

ConfigTypeDescriptionDefault
CONFIG_ZMK_RGB_UNDERGLOWboolEnable RGB underglown
CONFIG_ZMK_RGB_UNDERGLOW_EXT_POWERboolUnderglow toggling also controls external powery
CONFIG_ZMK_RGB_UNDERGLOW_AUTO_OFF_IDLEboolTurn off RGB underglow when keyboard goes into idle staten
CONFIG_ZMK_RGB_UNDERGLOW_AUTO_OFF_USBboolTurn off RGB underglow when USB is disconnectedn
CONFIG_ZMK_RGB_UNDERGLOW_HUE_STEPintHue step in degrees (0-359) used by RGB actions10
CONFIG_ZMK_RGB_UNDERGLOW_SAT_STEPintSaturation step in percent used by RGB actions10
CONFIG_ZMK_RGB_UNDERGLOW_BRT_STEPintBrightness step in percent used by RGB actions10
CONFIG_ZMK_RGB_UNDERGLOW_HUE_STARTintDefault hue in degrees (0-359)0
CONFIG_ZMK_RGB_UNDERGLOW_SAT_STARTintDefault saturation percent (0-100)100
CONFIG_ZMK_RGB_UNDERGLOW_BRT_STARTintDefault brightness in percent (0-100)100
CONFIG_ZMK_RGB_UNDERGLOW_SPD_STARTintDefault effect speed (1-5)3
CONFIG_ZMK_RGB_UNDERGLOW_EFF_STARTintDefault effect index from the effect list (see below)0
CONFIG_ZMK_RGB_UNDERGLOW_ON_STARTboolDefault on statey
CONFIG_ZMK_RGB_UNDERGLOW_BRT_MINintMinimum brightness in percent (0-100)0
CONFIG_ZMK_RGB_UNDERGLOW_BRT_MAXintMaximum brightness in percent (0-100)100

Values for CONFIG_ZMK_RGB_UNDERGLOW_EFF_START:

ValueEffect
0Solid color
1Breathe
2Spectrum
3Swirl
note

The *_START settings only determine the initial underglow state. Any changes you make with the underglow behavior are saved to flash after a one minute delay and will be used after that.

Devicetree

ZMK does not have any Devicetree properties of its own. See the Devicetree bindings for Zephyr's LED strip drivers.

See the RGB underglow feature page for examples of the properties that must be set to enable underglow.