An MIT research team reported last Thursday in Science Express (pdf available to Science subscribers) a novel method for transmitting power through the air. They are calling it WiTricity (pronouned “why” not “we” – why?), and there is a web site (witric.com) to follow events. It reports the spectacular rise from zero to over a million google results in the last 5 days.
Sending power through the air is certainly not new. It goes back at least to Nikola Tesla’s coils, which you can buy from Resonance Research if you are a science museum. But they aren’t safe! At high frequency high voltage your body’s nerves will not register a painful ZAP from the sparks – but damage to cells can occur. Indeed, Tesla coils have been the basis for death rays. WiTronics uses magnetic fields to transmit power. This has been studied extensively, since it is used in the medical procedure MRI, and is much safer.
Safety aside, the other innovation is using resonance to efficiently transmit the power. Without resonance the power would either dissipate in all directions, or need to be focused in a direct line of sight to the target device. Resonance allows the target device to selectively pluck power from the air, while intervening objects would not be affected. A prototype can transmit 60 watts across 2 meters with people in the airspace between the devices (see picture)…miniaturization TBD.