From the description on Kickstarter: The Crownstone is a power outlet for both the European and the American market, that uses Bluetooth Low-Energy to establish your presence through your smartphone. Moreover, it recognizes devices by very accurate current and voltage measurements.<p>The Crowstone is a multifunctional product that simultaneously brings you comfort and reduces your energy bills.<p>There is no need to turn off every device or lamp when you are going for groceries! The Crownstones are nice gadgets. However, they are more than just nifty products, they are a first step to make your home aware of you and your presence. The Crownstones become the eyes and ears of your home to optimally cater to your needs.