Digital Shower Temperature Device

  Alright, this is my greatest idea of all time. But I'm too busy to do it now, so maybe someone will do this and make the world a better place.
  How about a shower head that monitors the temperature and adjusts the hot and cold based on it. Imagine jumping into a shower with your favorite temp accurately pre-set. And if some dude down the hall flushes the john you don't get frozen.