RedstoneGateController

sleepTime = 0.1
timeLeft = 3


function openGate()
  print("openGate started")
  timeLeft = 3
  rs.setOutput("top", true)
  oldTime = timeLeft
  while timeLeft > 0 do
    if timeLeft ~= oldTime then    --if a new thread runs openGate, stop this thread
      return
    end
    sleep(sleepTime)
    timeLeft, oldTime = timeLeft - sleepTime
  end
  rs.setOutput("top", false)
end

while true do
  shell.run("clear")
  if rs.getInput("bottom") then
    print("redstone ON")
    print("creating coroutine")
    co = coroutine.create(openGate)
    coroutine.resume(co)
  else
    print("redstone OFF")
  end
  os.pullEvent("redstone")
end