Nokia, has harnessed the power of a phone that can recharge itself constantly based off olf ambient radio waves that travel through the air.

It takes all the waves from TV, radio, and other free-floating wireless signals that just bounce around the air and are either wasted, absorbed or scattered and converts the electromagnetic energy into electrical current which can then recharge the phone’s battery.

Currently Nokia is able to harvest all of 5 milliwatts from the air; the goal is to increase that to 20 milliwatts in the short term and 50 milliwatts down the line. That wouldn’t be enough to keep the phone alive during an active call, but would be enough to slowly recharge the cell phone battery while it’s in standby mode, theoretically offering infinite power — provided you’re not stuck deep underground where radio waves can’t penetrate.