Digital Camera News

Researchers at MIT Develop Wireless Power Source

November 22, 2006 – Researchers at the Massachusetts Institute of Technology are developing a non-radiative energy method for wirelessly powering consumer electronics, including mobile phones, laptops, and cameras.  Non-radiative electromagnetic energy could someday automatically power our household appliances without wires, according to the MIT researchers.

/o:p>The idea originated a year ago from a common frustration when MIT Assistant Professor Marin Soljacic of the Department of Physics and Research Laboratory of Electronics, found his cell phone battery had died.  /o:p>

Soljacic, along with Francis Wright Davis Professor of Physics John Joannopoulos and graduate student Aristeidis Karalis of the Department of Electrical Engineering and Computer Science, embarked on the idea that everyday media devices needed an easier power source. 

"It is a real world need," said Karalis in an interview with DigitalCameraInfo.com.  The MIT method for wireless energy could be used on "anything that operates on battery," said Karalis, including personal digital assistants and vacuum cleaners. 

The idea of automatic recharging consumer media devices is derived from the principals of physics.  Traditionally, wireless energy has been used inefficiently.  Electromagnetic radiation such as radio waves project energy in all directions, and some power is then lost. 

The method MIT researchers are currently working on contains the energy with a non-radiative field.  Energy at a particular frequency can cause objects to vibrate.  Two objects at the same frequency are particularly strong candidates for energy transfer, said Soljacic in a BBC News article published on Nov. 15.  A power transmitter such as a copper antenna resonates the electromagnetic waves, which is then picked up by a receiver, such as dead cell phone battery. 

The non-radiative energy transfer from the transmitter to the receiver, however, is currently limited to a range of a few meters.  The wireless energy transfer would not be helpful for someone stuck in the middle of the desert with no power source.

Still, photographers dream of the day when they can shoot without looking at battery life.  If the wireless energy research and technology advances, "you would never have to bother to charge your camera battery," Karalis said. 

There are concerns about the possible radiation effects this technology could have on people.  MIT is currently conducting tests about the levels of this kind of radiation exposure to see if it is safe for humans, of which standards are controlled by the FCC.  Karalis suspects the radiation levels are similar to those of an MRI and should be safe. 

If the testing is successful, non-radiative wireless energy could have far-reaching possibilities, from charging our cells to powering our cars with wires underneath our streets, according to Karalis.  The researcher points out that the technology is still in the beginning stages and the applications are still only hopes.