sensor

prox = peripheral.wrap("top")
 mon = peripheral.wrap("left")

while true do
players = prox.getPlayers()
mon.clear()
mon.setCursorPos(2,3)

if #players ~= 0 then
  local h = fs.open("visitor", fs.exists("visitor") and "a" or "w")
    for a,b in pairs(players) do
    h.writeLine( b.name .. " @ " .. os.time() )
    mon.write(b.name)
    end
  h.close()
end

sleep(0.1)

end