hardware_base.rb

module HardwareBase

  def self.register_device_type mod, sym
    @@device_registrations ||= {}
    @@device_registrations[sym] = mod
  end
  
end

module Servo
  include HardwareBase

  HardwareBase.register_device_type self, :servo
  
  def output_pin_setup(num,opts)
	  puts "setting up output pins for servo"
  end
end

module I2C
  include HardwareBase

  HardwareBase.register_device_type self, :i2c
  
  def output_pin_setup(num,opts)
	  puts "setting up output pins for i2c"
  end
end

class ArduinoSketch
  include HardwareBase
  
  def initialize
    puts @@device_registrations.inspect
  end
  
  def output_pin num, opts={}
    ArduinoSketch.send(:include, @@device_registrations[opts[:device]])
    output_pin_setup num, opts
  end
end

as = ArduinoSketch.new#.device_registrations.inspect
as.output_pin 7, :as => :servo, :device => :servo