New Tech
sciencepunk | October 1, 2009
Researchers have submitted a paper for publication (read preprint) detailing how to use WiFi to see through walls. The system works by measuring interference between nodes of wireless devices. When someone walks through the field, the change in resistance is detected and plotted by a central computer. Ars technica reports:
The basic idea behind the work is the assumption that transmissions between any two IEEE 802.15.4 devices travel within an ellipse centered on a straight line between those points. It's not possible to know which path a given transmission took, as different paths will…
sciencepunk | May 11, 2009Talking to submarines is a very a tricky business - most communication systems are based on radio or acoustic signals, but neither travel very far in water. This means that to pick up radio signals, submarines must surface or raise communication buoys very close to the surface, neither of which are appropriate for nuclear-powered stealth submarines that remain deep underwater for months at a time.
Radio operators can overcome the problem of poor signal penetration by using giant arrays broadcasting in extremely-low frequency ranges, but these are expensive, difficult to build, and…