Privacy??

Ever wonder if someone is watching you and you have no idea who it is? Ever think that your safe in your own home? Thanks to Darpa the Defense Department's way-out research arm, is looking to develop a suite of tools for "external sensing deep inside buildings." The ultimate goal of this Harnessing Infrastructure for Building Reconnaissance (HIBR) project: "reverse the adversaries' advantage of urban familiarity and sanctuary and provide U.S. Forces with complete above- and below-ground awareness. They would be able to see a full blueprint of the building and also track people inside these buildings. These bluepritnts are not limited to electrical, plumbing, and ventilation systems.


Darpa's research uses a kind of radar to scan structures. The problem is not sending the radio frequency (RF) energy in. It's making sense of the data produced from all the reflected signals that come back. The system also must filter a large amount of RF propagation in the form of randomly reflected signals. Although radar technologies exist that can track people in adjacent rooms, it is much more difficult to map an entire building.

Wireless Power

Has your cell phone battery ever died on you because you forgot to plug it into the charger the night before? How does a wireless power source sound that can charge your phone as soon as you walk into your house. A few years ago, Marin Soljačić, an assistant physics professor at MIT, was woken up by the insistent beeping of his cell phone. Since he was so exhausted, he wished that the phone would charge by itself as soon as it was brought into his house. After that day Soljačić tried to find ways to transmit power wirelessly that could charge--or even power--portabl­e devices such as cell phones, PDAs, and laptops.


So far, the most effective setup consists of 60-centimeter copper coils and a 10-megahertz magnetic field; this transfers power over a distance of two meters with about 50 percent efficiency. The team is looking at silver and other materials to decrease coil size and boost efficiency. "While ideally it would be nice to have efficiencies at 100 percent, realistically, 70 to 80 percent could be possible for a typical application," says Soljačić.