CC Redstone Timer

TIME = 300 -- input your time (in seconds)
running = true

while running do
 local time = TIME
 while time > 0 do
  print(time.." seconds remaining")
  local first = os.startTimer(1)
  while true do
   local event, timerID = os.pullEvent("timer")
   if timerID == first then
     time = time - 1
     break
   end
  end
 end
 local second = os.startTimer(1)
 rs.setAnalogOutput("left", 15)
 while true do
  local event, timerID = os.pullEvent("timer")
  if timerID == second then
   break
  end
 end
 rs.setAnalogOutput("left", 0)
end