ev3_led_patch.rb

module EV3
  module UiWriteSubcodes
    LED = 27 # ev3sources/lms2012/lms2012/source/bytecodes.h
  end
  
  module Commands
    class UiWrite < Base
      UI_WRITE_SUBCODES__LED = 27  
      # color: 0-9  
      def set_led(color)
        if !color.is_a?(Integer) || !(0..9).include?(color)
          raise "invalid color: #{color.inspect}"
        end
        @message +=
          ByteCodes::UI_WRITE.bytes +
          [UiWriteSubcodes::LED] +
          [color]
        return self
      end
    end
  end

  class Brick
    def set_led(color)
      Commands::UiWrite.new(@connection).
        set_led(color).
        command_type(CommandType::DIRECT_COMMAND_NO_REPLY).
        send_command
    end
  end
end

# usage:
#   @brick.set_led(6)
#
=begin
  LED_BLACK                     = 0,  <- turn off LED
  LED_GREEN                     = 1,
  LED_RED                       = 2,
  LED_ORANGE                    = 3,
  LED_GREEN_FLASH               = 4,
  LED_RED_FLASH                 = 5,
  LED_ORANGE_FLASH              = 6,
  LED_GREEN_PULSE               = 7,
  LED_RED_PULSE                 = 8,
  LED_ORANGE_PULSE              = 9,

Refereces:
  - http://analyticphysics.com/Diversions/Assembly%20Language%20Programming%20for%20LEGO%20Mindstorms%20EV3.htm
  - EV3 Firmware Developer Kit documentation
    https://education.lego.com/en-us/support/mindstorms-ev3/developer-kits
   


=end