Air guitar makes music

CANBERRA, Australia -- Posers can become performers with a high-tech T-shirt that turns the strumming of an air guitar into music.

Motion sensors built into the shirt's elbows pick up the wearer's arm motions and relay them wirelessly to a computer that interprets them as guitar rifts, said Richard Helmer, an engineer who leads the research team from the government's Australian Commonwealth Scientific and Industrial Research Organization. (Video demonstration: www.youtube.com/user/csiromedia)

Mr. Helmer, 34, a part-time guitarist with several bands, said he did much of the development at home as "a more fun product" that built on research that the government organization conducted into monitoring the knee movements of professional soccer players.

With strong interest in the "wearable instrument shirt" since the prototype was revealed Monday, Mr. Helmer is considering going into commercial production soon.

Recharging without cords

WASHINGTON -- There may be hope -- however distant -- for recharging cell phone, laptop and other batteries without plugging them into the wall, a scientist said.

Although he hasn't built a device yet, Massachusetts Institute of Technology physics professor Marin Soljacic said he had figured out how to wirelessly recharge batteries, much like the way people can surf the Web untethered.

In a presentation at an American Institute of Physics forum in San Francisco, Mr. Soljacic made the case for using specially tuned waves of electromagnetism that don't radiate like normal waves.

The idea is that the recharge device and the receiver would be on the same acoustic frequency, similar to how a radio picks up only one channel at a time, so that the energy would mostly go straight to the intended battery, Mr. Soljacic said.

Some of the electromagnetic energy would go elsewhere but Mr. Sojacic doesn't believe it would harm people, noting that humans can endure strong magnetic fields with magnetic resonance imaging machines.

Mr. Soljacic envisions a device with wiring loops mounted on the ceiling of a room. He even sees this as a way of recharging electric buses on the go if there's a large "pipe" with recharging energy above a highway.

The concept of wirelessly recharging batteries has been dismissed before, deemed way too inefficient with too much energy put out into the air and little where it's supposed to go. But Mr. Soljacic said using special resonating frequencies could theoretically cut energy loss to only half of the energy produced, making the technology usable.

MP3.com hosting music again

LOS ANGELES -- MP3.com is reopening its servers, nearly a decade after it helped usher in the online music era by letting largely unknown bands submit files for computer users to download.

The site, acquired by San Francisco-based CNET Networks Inc. in 2003, has undergone a redesign. Relaunched officially on Tuesday, the site now offers up to 100 megabytes of storage space for audio tracks and unlimited space for videos, free of charge.

The company won't say how many independent artists or tracks have been uploaded to the site since it began accepting files a few weeks ago.

CNET bought only the Internet domain, not the library of more than 1 million tracks that bands had uploaded to MP3.com since 1998.

So, until recently, the site focused on offering editorial content on major label artists and enabled visitors to stream selected tracks and videos while online, typically with links to Internet music stores where fans could buy downloads for portable devices and offline play.

The revamped site weaves in tracks and videos by independent and unsigned bands for visitors to download directly from MP3.com. It gives at least some of the fledgling acts equal billing with similar artists from major labels.