local exitTime = 22 -- change to whatever you want
local timer = os.startTimer(exitTime) -- starts the timer
local cp = 0
local cm = 0
while true do
  local evt, arg = os.pullEvent() -- wait for an event
  if evt == "timer" then
        if arg == timer then -- check if it's the correct timer
            redstone.setOutput("top",true)
        cp = cp +1
            textutils.slowPrint ("Send redstonsignal! "..cp)
    end
  elseif evt == "redstone" then
        timer = os.startTimer(exitTime) -- restarts the timer
        redstone.setOutput("top",false)
    cm = cm +0,5
    textutils.slowPrint ("Dont send redstonsignal! "..cm)
  end
end