maestro.rb

#!/usr/bin/env ruby

require 'serialport'

class Maestro
  def initialize
    @sp = SerialPort.new("/dev/ttyACM0")
  end

  def send(servo, position)
    mess = "#{0x84.chr}#{servo.chr}#{(position & 0x7f).chr}#{((position >> 7) & 0x7F).chr}"
    @sp.write mess
  end
end

m = Maestro.new
loop do
  (4000..8000).step(10) do |n|
    m.send(0, n)
    sleep 0.05
  end
end