updated 05:00 pm EDT, Fri July 24, 2009
WiTricity wireless power
At the TED Global Conference in Oxford, UK wrapping up today, US-based WiTricity showed off a wireless charging system that powered up a T-Mobile G1, Apple's iPhone and a flat screen TV. Such a system could eventually replace the current infrastructure that involves countless miles of power cable and disposable alkaline batteries. According to a recent BBC report, the system is based on research by a physicist at the Massachusetts Institute of Technology (MIT), Marin Soljacic. It uses low frequency electromagnetic wave resonance to transfer the energy from the source to the device via a coil at each end.
Each of the coils is engineered to have the same resonant frequency. Each cycle of energy arriving at the receiving coil produces a voltage that can charge the gadget. Devices so equipped automatically charge when they are in the range of the main charging coil, so there's never a need to plug devices in. The energy is transferred via magnetic fields, so there is no danger or interference with other devices, the demo showed. Because of the near field effect -- less than one wavelength -- there is no potentially dangerous electric fields, but only magnetic waves. The electromagnetic waves are only about 100ft long, and shorter wavelengths would not work.
The demo had a G1 that looked no different than the regular headset, as all the necessary components were integrated into the body of the device. Apple's iPhone required an add-on sleeve module, as space inside the headset is at a premium.
WiTricity's chief executive, Eric Giler, envisions his company's technology to be used to charge all types of devices, from cellphones and notebooks to pacemakers and electric cars.