timer

m = peripheral.wrap("back")
rednet.open("right")
t = 31
z = 31
while true do
  while t>0 do
    t = t-1
    m.clear()
    m.setCursorPos(3,1)
    m.setTextScale(3)
    m.write("time until")
    m.setTextScale(3)
    m.setCursorPos(3,2)
    m.setTextScale(3)
    m.write("light bridge:")
    m.setCursorPos(3,3)
    m.write(t)
    sleep(1)
  end
  while t==0 do
    z = z-1
    rednet.send(7,"go")
    rednet.send(7,"stop")
    m.clear()
    m.setCursorPos(3,1)
    m.setTextScale(3)
    m.write("time until")
    m.setCursorPos(3,2)
    m.setTextScale(3)
    m.write("bridge goes off:")
    m.setCursorPos(3,3)
    m.setTextScale(3)
    m.write(z)
    sleep(1)
    if z == 0 then
      t=31
      z=31
    end
  end
end