Recharging Gadgets Wirelessly

A metal pad that can recharge devices placed on top of it has come to market.

The chore of recharging cell phones, PDAs, MP3 players, cameras, and laptops is perhaps one of the more frustrating side effects of modern technology. Charger cables are usually tangled in nests near outlets or behind desks. And anyone traveling for more than a day with an electronic gadget has to tote along its clunky charger as well. A Delaware-based startup called WildCharge thinks that it has a better approach. The company is selling a small metal pad, about the size of a sheet of paper, that can simultaneously charge multiple devices laid on top of it--as long as they're equipped with adaptors. WildCharge is now selling an adaptor for Motorola Razr phones, and it's developing others.

Power pad: Delaware-based WildCharge has developed an electrically conducting pad that charges phones and other devices via adaptors. Above, the battery cover of a Motorola Razr mobile phone has been replaced by WildCharge’s adaptor, which has four metal contacts arranged in a Y shape. Credit: WildCharge

"WildCharge is the industry first in wire-free charging," says Mitch Randall, the company's chief technology officer and inventor of the technology. He says that it was easy to bring the power pad to consumers because the technology is fairly straightforward, while other companies and research teams are still ironing out kinks in their approaches. "There are no other competitors on the market because they're still fighting their technology," he says. "Ours just works, and it's cheap."

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In recent years, a number of wireless-power technologies have garnered some attention. Researchers at the University of Tokyo have developed a sheet of plastic with printed electronics that charges gadgets using a technique known as inductive coupling. (See "Plastic Sheet of Power.") In the researchers' prototype, electric current flows through a coil, inducing a magnetic field. This magnetic field, in turn, induces a current in a coil within or attached to a device that is touching or nearly touching the pad--the same way that an electric toothbrush charges on its pedestal. Still, the research is early, and the printed electronics aren't reliable enough to be used in a commercial product. At MIT, another group of researchers recently demonstrated a wireless-power setup that uses large coils to charge gadgets up to three meters away; they are currently working to commercialize the technology. (See "A Wirelessly Powered Lightbulb.")

Randall explains that WildCharge took a different, simpler approach. The power pad--originally designed to power action figures for a child's game--consists of metal strips that conduct electricity. In order for a gadget to be recharged by the pad, it needs an adaptor, which plugs into its charging port and consists of four metal contacts. When the contacts touch the metal strips on the pad, electricity flows directly into the battery of the gadget. Essentially, the contacts "close the circuit," says Randall, "just like flipping a light switch." For safety, Randall says, the pad shuts down when an object that isn't WildCharge-enabled comes in contact with it; but the mechanism behind that feature is proprietary, he says. If there are no devices in contact with the pad, then after 30 seconds, it goes into a standby mode to conserve power.