timer.rb

finished = true
timer = EM::PeriodicTimer.new(5) do
  if finished
    finished = false
    method = http.post :body => { data: { serial_no: serial } }
    method.errback { $stderr.puts 'Can\'t connect to cloud'; finished = true } 
    method.callback do
      finished = true
      p method.response_header.status
      p method.response_header
      p method.response
    end
  end
end