delcom_904008.rb

#!/usr/bin/env ruby
#
# Author: Ian Leitch <ian@envato.com>
# Copyright 2010 Envato

require 'usb'

module Delcom
  class SignalIndicator
    VENDOR_ID = 0x0fc5
    PRODUCT_ID = 0xb080
    INTERFACE_ID = 0

    OFF = "\x00"
    GREEN = "\x01"
    RED = "\x02"
    YELLOW = "\x04"

    def initialize
      @device = USB.devices.find {|device| device.idVendor == VENDOR_ID && device.idProduct == PRODUCT_ID}
      raise "Unable to find device" unless @device
    end

    def green
      msg(GREEN)
    end

    def yellow
      msg(YELLOW)
    end

    def red
      msg(RED)
    end

    def off
      msg(OFF)
    end

    def close
      handle.release_interface(INTERFACE_ID)
      handle.usb_close
      @handle = nil
    end

  private
    def msg(data)
      handle.usb_control_msg(0x21, 0x09, 0x0635, 0x000, "\x65\x0C#{data}\xFF\x00\x00\x00\x00", 0)
    end

    def handle
      return @handle if @handle
      @handle = @device.usb_open
      begin
        # ruby-usb bug: the arity of rusb_detach_kernel_driver_np isn't defined correctly, it should only accept a single argument.
        if USB::DevHandle.instance_method(:usb_detach_kernel_driver_np).arity == 2
          @handle.usb_detach_kernel_driver_np(INTERFACE_ID, INTERFACE_ID)
        else
          @handle.usb_detach_kernel_driver_np(INTERFACE_ID)
        end
      rescue Errno::ENODATA => e
        # Already detached
      end
      @handle.set_configuration(@device.configurations.first)
      @handle.claim_interface(INTERFACE_ID)
      @handle
    end
  end
end