Looking for an easy, cheap way to spy on your neighbors? Researchers are working on a device that may be just the thing, which uses a simple wireless network to “see” through a wall and detect people moving around in the room beyond. But paranoid apartment-dwellers will be glad to know that the system still has plenty of limitations. At the moment the system can only track movement within a three-foot range, and it can only sense motion–it can’t put together a picture of what or who’s moving.
The system relies on the variations of radio signals in a wireless network. The signal strength at any point in a network is the sum of all the paths the radio waves can take to get to the receiver. Any change in the volume of space through which the signals pass, for example caused by the movement of a person, makes the signal strength vary. So by “interrogating” this volume of space with many signals, picked up by multiple receivers, it is possible to build up a picture of the movement within it [Technology Review]. The paper describing the technology has been posted on the arXiv pre-print server, and has not yet been peer-reviewed.
The device could be more than a boon for voyeurs or robbers. The researchers argue that the technology could be used in search and rescue operations, with emergency teams using the same radio technology used by Wi-Fi networks to build a web of sensors around a disaster site, revealing the location of victims and survivors [Telegraph].
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Image: Joey Wilson and Neal Patwari
October 2nd, 2009 at 1:55 pm
sweet!!, it’s a start but i like it!!
October 2nd, 2009 at 3:16 pm
Perhaps they could autocorrelate the fluctuations in signal (as is done in Dynamic Light Scattering) and determine patterns characteristic of different possible inhabitants…
October 2nd, 2009 at 3:20 pm
How likely is it people trapped in debris can move around? Apartment already have a spy networking option…don’t wear earplugs, you can tell where anyone in the floor above you is at when they move.
October 3rd, 2009 at 3:07 pm
Its not enough that big brother can watch you through your computer camera, he can see thru walls too. What next- process all cell phone calls through the NSA? Oh right, they already do that too.
Hold on, someones at the door.
October 3rd, 2009 at 11:42 pm
answer the door….hurry!
October 4th, 2009 at 6:43 am
this is still a long way to go.
not to mention rules and regulations for this.
October 4th, 2009 at 8:50 pm
not sure how that would help find people buried under rubble, where they’re not really able to move.
October 5th, 2009 at 3:46 pm
Sounds like STTW technology which has actually been around for a while:
http://www.slate.com/id/2200292/
http://articles.latimes.com/2008/sep/12/world/fg-pakistan12
What red dot on my head?