Inverse square law: A mathematical representation of how energy is dispersed over space, the inverse square law is useful in describing gravity, light, sound and all sorts of radiation. Energy falls off based on the square of the distance, so every time the distance is doubled, the energy available is one quarter of the original amount.
Piezoelectric materials: Piezoelectrics, like zinc oxide, are crystals that create electricity when squeezed or moved. They are used as sparkers in stoves, as sensors and as actuators.
Powercast isn't the only company developing RF-to-DC power technology. Nihon Dengyo Kosaku of Japan, for instance, has been working on a similar system that relies on a special rectifying antenna. Powercast, however, claims to have a head start on its competitors, saying it has chips ready to be integrated into products.
By 2012, Powercast hopes to have a household sensor product available to power smoke detectors that will never need to have their batteries changed. The company has also been working on shrinking its transmitters for home use. Ostaffe envisions a miniaturized transmitter "the size of a child's night light that would be powerful enough to power the smoke alarms in a modest-size home."
Nevertheless, distributing power over the air remains a tantalizing step or two away from mainstream availability. Although Powercast has the designs and chips ready, it needs a manufacturer to make and sell the actual products for consumers or businesses.
Self-healing batteries: Just-in-time repair
We all know the drill: You use your mobile device -- phone, tablet, laptop -- for a few years, then the battery dies and you have to replace it. Or you drop the device, the battery shorts out and you have to replace it even sooner.
And if a device isn't designed to allow the user to replace the battery himself (iPhones and iPads and other tablets are notorious for this), there's the extra hassle and expense of shipping the whole thing back to the manufacturer to swap out the battery.
But scientists at the Beckman Institute for Advanced Science and Technology at the University of Illinois at Urbana-Champaign have a better idea. Researchers led by professor Scott White are looking to extend the useful life of batteries in mobile devices, and they've figured out a way for the battery to fix itself, probably without the user ever knowing there was a problem.