portal.lua

while true do
    if redstone.getInput("back") then
      print("Received redstone signal.")
      sleep(1)

      print("Activated portal.")
      redstone.setOutput("top", true)
      sleep(1)
      redstone.setOutput("top", false)
      sleep(5)

      print("Activated portal again.")
      redstone.setOutput("top", true)
      sleep(1)
      redstone.setOutput("top", false)
    end

    os.queueEvent("someEvent")
    os.pullEvent()
  end