startup

print("Opening channel ..")
local p = peripheral.wrap("bottom")
p.open(1);

local gotEvent = false

function doSleep()
  sleep(1)
end

function doPull()
  local event, modemSide, senderChannel, replyChannel, message, senderDistance = os.pullEvent("modem_message")
  gotEvent = message == "GO"
end

while true do
  print("Sending signal ..")
  p.transmit(1, 1, os.getComputerLabel())

  parallel.waitForAny(doPull, doSleep)

  if gotEvent == true then
    print("Received GO signal")
  end
end