Charge your smartphones with Wi-Fi.

Allen Hawkes and Alexander Katko from Duke University's Pratt School have figured out a way to charge your smartphones  with  Wi-Fi.

They have developed a device with metamaterials that captures energy waves from wireless Internet and converts them into electrical current.

The device can wirelessly convert Wi-Fi’s microwave signals into direct current voltage to recharge a cell phone battery or other small electronic devices. Key to this power harvester are the metamaterials, which are engineered structures that can capture various forms of wave energy and tune them for useful applications. These energy sources could include satellite signals, sound signals or Wi-Fi signals.