Spying Made Simple: Wi-Fi Signals Used to See Through Walls

By Eliza Strickland | October 2, 2009 1:08 pm

wifi-through-wallsLooking 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 The paper describing the technology has been posted on the arXiv pre-print server, and has not yet been peer-reviewed.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].

Related Content:
Science Not Fiction: Knight Rider: Seeing Through Walls With Infrared Glasses?
80beats: Light-Bending Scientists Take a Step Closer to Invisibility

Image: Joey Wilson and Neal Patwari

CATEGORIZED UNDER: Technology
  • orlando tocano

    sweet!!, it’s a start but i like it!!

  • djanes1

    Perhaps they could autocorrelate the fluctuations in signal (as is done in Dynamic Light Scattering) and determine patterns characteristic of different possible inhabitants…

  • addicted to bad

    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.

  • Pat Riot

    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.

  • http://yahoo dwhitlow

    answer the door….hurry!

  • http://robinferianto.com/ robb

    this is still a long way to go.
    not to mention rules and regulations for this.

  • http://yahoo.com urb

    not sure how that would help find people buried under rubble, where they’re not really able to move.

  • spyme

    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?

  • http://osc3.template-help.com/forum_16282/profile.php?mode=viewprofile&u=32729 Laquanda Atienza

    I acquired listed here because of Search engines. This unique appears a great posting. I just completely relished reading your web blog, i will probably be certain to keep coming back. I just set aside your blog and that i moreover passedyour can i just a few relations on top of that. I think you will don’t thoughts!

  • http://www.spielegarten.com spiele

    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.

NEW ON DISCOVER
OPEN
CITIZEN SCIENCE
ADVERTISEMENT

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

80beats

80beats is DISCOVER's news aggregator, weaving together the choicest tidbits from the best articles covering the day's most compelling topics.
ADVERTISEMENT

See More

ADVERTISEMENT
Collapse bottom bar
+

Login to your Account

X
E-mail address:
Password:
Remember me
Forgot your password?
No problem. Click here to have it e-mailed to you.

Not Registered Yet?

Register now for FREE. Registration only takes a few minutes to complete. Register now »