Vincent,
For the proximity detector, how close do you need to get before it detects you? At our house, we have a touch sensor water faucet in our kitchen (our model is called "Touch2O," not homemade), but upgrading it to turn on/off based on proximity detection to the surface would be even better. My wife wanted it, and although I was skeptical about how useful it would be when we bought it, I'm sold on the idea now. It really is a nice feature! We've been using it now for 7 years. When it's something you use everyday all the time, upgrades can be really worth it.