Wireless Network Modded To See Through Walls 161
KentuckyFC writes "The way radio signals vary in a wireless network can reveal the movement of people behind closed doors, say researchers who have developed a technique called variance-based radio tomographic imaging which processes wireless signals to peer through walls. They've tested the idea with a 34-node wireless network using the IEEE 802.15.4 wireless protocol (the personal area network protocol employed by home automation services such as ZigBee). The researchers say that such a network could be easily distributed by the police or military wanting to determine what's going on inside a building. But such a network, which uses cheap off-the-shelf components, might also be easily deployed by your neighbor or anybody else wanting to monitor movements in your home."
The Dark Knight (Score:3, Informative)
Re:Tinfoil House (Score:3, Informative)
Looks like it is time to get hold of some Aluminum Oxide paint.
Looks like it is time to start making cell phone calls from outside.
Re:Fear mongering (Score:3, Informative)
What, did you shower with your eyes closed?
How do you not realize that you can see the road from the shower if people can see in the shower from the road?
Google Maps? (Score:3, Informative)
"We envision a building imaging scenario similar to the following. Emergency responders, military forces, or police arrive at a scene where entry into a building is potentially dangerous. ... The nodes immediately form a network and self-localize, perhaps using information about the size and shape of the building from a database (eg Google maps) and some known-location coordinates (eg using GPS).
Anyone remember http://en.wikipedia.org/wiki/NATO_bombing_of_the_Chinese_embassy_in_Belgrade [wikipedia.org]?
Oops! Map was wrong and we are in the wrong house!
Re:Tinfoil House (Score:3, Informative)
Aluminum oxide is a dielectric with breakdown around 16kV/mm and dielectric constant of 9. That puts the material in a class similar to glass. As such it would be among the most ineffective Faraday cages since the walls of such a cage must be conductive, and to be truly effective, VERY Conductive. In fact, at high RF ranges light weight cages and shielding have to be made of silver, gold, etc. to keep the skin effect thickness of the material down to manageable values. What is interesting about the aluminum oxide dielectric is its apparent very lossy nature to some RF frequencies, while being "transparent" to others. That is sort of similar to the behavior of pure water, which, if absolutely pure, is a dielectric, but as a polar dielectric it absorbs high frequencies in your microwave oven or in the atmosphere between me and my geosynchronous internet satellite.
The usefulness of aluminum oxide as a dielectric has been known a long time and electrolytic capacitors used as power supply filters, among other things, use its characteristics to make large capacitances in small volumes.
Competition (Score:3, Informative)
Although this thing idea is neat, there is an Israeli company that is currently selling RF tech to do the same thing. It comes in a package the size of a suitcase, and can be deployed without having to put transmitters/receivers all over the place. Check it out.
I actually applied to work for that company but wasn't smart enough. Blasted Israelis and their blasted smarter-than-me-ness.
I did some searching, here's a video: (Score:4, Informative)
Videos at their website (Score:4, Informative)
Check out their demonstration videos at http://span.ece.utah.edu/radio-tomographic-imaging [utah.edu].
I was fortunate enough to see the demo at Mobicom last year. It's a really neat application, even if the math is nothing new.
Re:Wow innovation! (Score:4, Informative)
Ah, propellerheads, hello? (Score:3, Informative)
They just reinvented RADAR for pity's sake! What is 802.xx? 2-5GHZ Microwave frequencies! It's rather like reinventing the wheel, only this time they used millimeter band, low powered microwaves to do it with. Hooray they are able to use it as a poor man's license-free RADAR system, I'll give them credit for that.
Thank goodness for Kyllo vs. U.S. (Score:4, Informative)
... wherein the Supreme Court (including Scalia, amazingly) held that peering into homes using equipment that was not available in common use by the layperson was within the bounds of the 4th amendment, and therefore requires a search warrant.
Re:In 20 years..... (Score:2, Informative)
Re:The Dark Knight (Score:1, Informative)
Tyvek is paper, with controlled porosity, to let air and water vapor through whilst keeping out dust. You are probably thinking of foil-backed fibreglas wool.