ComputerCraft script for controlling my RedPower frame castle gate

gatecontrol.lua

-- Castle Gate Control
-- Opens and closes a redpower frame gate at the push of a button
 
 local side = "left" -- Bundled cable location
 local alarmSide = "back" -- Howler alarm location
 
function enableWire(color) -- Turn on a colored wire in the bundle without affecting the other colors
  local currentSet = rs.getBundledOutput(side)
  if not colors.test(currentSet, color) then
    currentSet = colors.combine(currentSet, color)
    rs.setBundledOutput(side, currentSet)
  end
end
 
function disableWire(color) -- Turn off a colored wire in the bundle without affecting the other colors
  local currentSet = rs.getBundledOutput(side)
  if colors.test(currentSet, color) then
    currentSet = colors.subtract(currentSet, color)
    rs.setBundledOutput(side, currentSet)
  end
end
 
function pulseWire(color) -- Turn a wire on and off
  enableWire(color)
  os.sleep(0.5)
  disableWire(color)
  os.sleep(0.5)
end

write("== Castle Gate Control ==\n")

-- Reset the redstone
rs.setBundledOutput(side, 0)
rs.setOutput(alarmSide, false)

-- Start with the gate in a closed position
pulseWire(colors.red)
pulseWire(colors.red)
pulseWire(colors.red)
local raised = 0

while true do
  local evt, arg = os.pullEvent()
  if evt == "redstone" then
    local currentSet = rs.getBundledInput(side)
    if colors.test(currentSet, colors.yellow) then
      if raised == 0 then
        write("Opening the gate!\n")
        rs.setOutput(alarmSide, true)
        os.sleep(1)
        pulseWire(colors.white)
        pulseWire(colors.white)
        pulseWire(colors.white)
        os.sleep(1)
        rs.setOutput(alarmSide, false)
        raised = 1
      else
        write("Closing the gate!\n")
        rs.setOutput(alarmSide, true)
        os.sleep(1)
        pulseWire(colors.red)
        pulseWire(colors.red)
        pulseWire(colors.red)
        os.sleep(1)
        rs.setOutput(alarmSide, false)
        raised = 0
      end
    end
  elseif evt == "key" then
    if arg == 45 then -- X key pressed on keyboard, exit the program
      write("Exit!\n")
      break
    end
  end
end