The radio waves that saturate the air around us may, or may not, give us headaches
, but we can tell you for certain they're capable of powering tiny wireless chips. Renesas Electronics Corp has created a new ultra-low power wireless transmitter that can push data to both Bluetooth and WiFi receivers without the need for a battery or AC adapter. Instead of the typical tens of milliwatts, the little transmitters require only a few microwatts of power, which can be harvested from environmental radio waves through LC resonance. The creators envision adhesive sensors that send a baby's body temperature to laptops and ads that beam coupons to smartphones over short distances -- you know, the sort of stuff NFC can do, but without the specialized hardware.