Num Lock, Caps Lock and Scroll Lock

Valid version

0.9.14+

Description

You can get a callback when the status of "Num Lock", "Caps Lock" and "Scroll Lock" in the host device is changed.

Usage

If you want an LED to turn on when Caps Lock turned on

led_pin = 25 # It's the on-board LED of Raspi Pico
gpio_init led_pin
gpio_set_dir led_pin, Keyboard::GPIO_OUT
gpio_put led_pin, 0

kbd.output_report_changed do |output|
  gpio_put led_pin, (output & Keyboard::LED_CAPSLOCK > 0 ? 1 : 0)
end

Likewise, if you want RGBLED to change its color

rgb.effect = :breath
rgb.hue = 0
rgb.speed = 25
kbd.append rgb

kbd.output_report_changed do |output|
  if output & Keyboard::LED_CAPSLOCK > 0
    rgb.hue = 100
  else
    rgb.hue = 0
  end
end

See RGBLED for details.

Coverage

The block variable output in the above examples has the status that you can extract by bit operation:

output: 0b11111
              ^ Num Lock
             ^  Caps Lock
            ^   Scroll Lock
           ^    Compose
          ^     Kana

If a bit is 1, the corresponding function is locked in the host PC.

Keycode	Alias	Mask constant	Value
:KC_NUMLOCK	:KC_NLCK	Keyboard::LED_NUMLOCK	0b00001
:KC_CAPSLOCK	:KC_CAPS	Keyboard::LED_CAPSLOCK	0b00010
:KC_SCROLLLOCK	:KC_SLCK	Keyboard::LED_SCROLLLOCK	0b00100
N/A	N/A	Keyboard::LED_COMPOSE	0b01000
N/A	N/A	Keyboard::LED_KANA	0b10000

LED_COMPOSE and LED_KANA are implemented according to the HID descriptor though, dev team hasn't check the actual function.