

Wi-Fi signals enable gesture recognition throughout entire home - risent
http://www.washington.edu/news/2013/06/04/wi-fi-signals-enable-gesture-recognition-throughout-entire-home/

======
networked
_> A standard Wi-Fi router could be adapted to function as a receiver._

The article and the embedded video do not make it entirely clear but if this
technology could be deployed in existing Wi-Fi routers with relative ease [1]
then it could have far-going implications for both privacy and the physical
security of anywhere where there's Wi-Fi. Once it's easy enough to deploy on a
hacked device that a hired script kiddie can do it even simple burglars could
take an interest in residential routers to know when nobody's home.

I wonder if this will affect the market for embedded Linux security consulting
in a major way.

[1] I.e., without modifying the hardware and with no need for manual
calibration.

~~~
deserted
From the paper [1]

 _The WiSee proof-of-concept is implemented in GNURadio using the USRP-N210
hardware._

 _Each USRP is equipped with a XCVR2450 daughterboard, and communicates on a
10 MHz channel at 5 GHz. Since USRPN210 boards cannot support multiple
daughterboards, we built a MIMO receiver by combining multiple USRP-N210s
using an external clock. In our evaluation, we use MIMO receivers that have up
to ﬁve antennas. We use single antenna USRP-N210s as transmitters._

So basically, they are using 6+ USRPs at $1400+ each to do these experiments.
However, since each USRP is communicating on a 10MHz channel at 5GHz, someone
with between two and five MIMO 802.11n Wi-Fi devices could theoretically do
the same.

[1] <http://wisee.cs.washington.edu/wisee_paper.pdf>

~~~
thinkling
I think you'd still have to hack the routers to provide the external clock, as
the whole scheme depends on accurate sensor fusion between multiple antennas.

~~~
aortega
Not only you have to hack the routers, once inside the router you'll have to
flash a custom wireless firmware, or "radio" firmware. And also the Chipset
must be flexible enough to allow all the iFFT shenanigans. I think it's a
stretch to say you could do this with a common wifi device, maybe with a very
specific wifi chipset you could, and maybe you could make it work with
bluetooth or wireless phone chipsets aswell.

That said, it's an excellent paper about a soft-based radar.

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kingkawn
This sounds a lot like the mobile phone sonar that Batman used in the Dark
Knight which seemed utterly ridiculous to me and many others at the time:

[http://sfblunders.wordpress.com/2008/08/07/dark-knight-
sonar...](http://sfblunders.wordpress.com/2008/08/07/dark-knight-sonar-
phones/)

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ChuckMcM
Ok DD-WRT folks, get to it :-) More seriously though, this is a pretty cool
thing, using your motion which is blocking wireless signals to detect motion.
In hindsight its kind of obvious since people are 'giant waterbags of
attenuation' as my RF buddy calls them. This also means you can probably add
something of a burglar alarm/motion sensor system to these things, and if you
were careful you might be able to see the movement of people inside a house by
looking at the WiFi signal leaving the house. Certainly if you're carrying
around and active phone/tablet that would be trivial to do from outside (and
by trivial I mean you would have lots of signal to work with and the math
would be straight-forward, not that it would be simple)

~~~
stephengillie
We can track people, cool! And probably kids too! What about dogs and cats?
Rats, mice, and cockroaches?

What's the range on this technology, and what happens if we move the router
around with us? Maybe we take it to a new building and plug it in there? Or
maybe we can use the wifi modules on phones to do this also? It sounds like a
great scanning device. And how long before we can also see huge chunks of
metal or strong magnets with this technology, based on how radio waves
interact with them?

~~~
aidenn0
6cm is the wavelength at 5GHz and most sensing devices have issues with sub-
wavelength objects. If you're paranoid you can hang a bunch of strips of
aluminum foil that are 3cm long all around your house, which could confuse the
sensor. (see <http://en.wikipedia.org/wiki/Chaff_(countermeasure)>)

~~~
theoj
Work is underway on 60Ghz Wifi, which has wavelengths of only a few
millimeters.

[http://www.pcworld.com/article/2030041/meet-60ghz-wi-fi-
the-...](http://www.pcworld.com/article/2030041/meet-60ghz-wi-fi-the-insanely-
fast-future-of-wireless-networking.html)

In a few years we could have tri-band routers covering 2.4Ghz, 5Ghz and 60Ghz.
Correlating the info from all these frequencies should provide a much better
picture.

------
rvasa
Oh the possibilities of this - may be with enough data \- you can just wander
around a suburb and figure out which houses are currently occupied and which
ones are not. \- improve aged care by monitoring walking patterns \- combine
it with some more ingenious technology for localised sound -- you can beam
music as I walk around the house (or block out sounds)? \- a bit more
sensitivity and we can even probably pick up a person while they are having or
just about to have a heart attack?

I am sure the privacy folk out there are having multiple heart palpitations.

All I want to say is "bring it on"

~~~
finnw
And maybe predict domestic violence before it happens.

I'm not sure if I qualify as one of the "privacy folk" or not, but I would say
"As long as the police cannot compel you to install the thing and switch it
on, or have an AI system issue search warrants in seconds based on what the
machine reports." Unfortunately I think we will have both of those things 20
years from now.

~~~
danbruc
There is no need to force anybody to install and turn on anything - they could
just passively monitor the signal of your wireless router, our that of your
neighbor or of your cellphone. Or they could actively send such a signal and
analyze it if they don't care about being detected. In the end it is some kind
of (passive) radar and you will probably have to actively jam or block it in
order to prevent someone from monitoring you.

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JonnieCache
Look out for lots of <img/> tags pointing to
<http://192.168.1.100/epic_firmware_fail.cgi?sploit=PAYLOAD>!

------
niels_olson
> Neighbor: Why do you always wave your hands around?

> Me: It's the preamble to the spell where I invoke the deamons

> Neighbor: Why the stick?

> Me: Improves gain

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OldSchool
I've often wondered is to what extent existing RF noise as "illumination"
could be leveraged to effect some kind of passively acquired representation of
objects. Resolution would of course be limited by wavelength but improved if
the antenna array was physically moving in a describable manner. We had useful
SAR during the cold war and orders of magnitude more compute power today. If
you know of more efforts along these lines from hacker to research level,
please post a link.

------
chopsueyar
Can this differentiate between multiple humans gesturing at the same time
(intentional or otherwise)?

What about pets moving around or turning the shower on?

~~~
hammock
Your pet turns the shower on? That sounds like a real problem

~~~
Someone
I think he refers to having a system that, using this approach, turns on his
shower when he enters it. If this cannot distinguish humans from cats, it
would turn on the shower when a cat entered it.

I think that's a bad example. The typical cat would soon learn not to enter
the shower.

~~~
archon
> I think that's a bad example. The typical cat would soon learn not to enter
> the shower.

My black lab, however, would enter the shower every time I forgot to close the
door.

------
est
So this was basically an S-band radar with a home wifi router? Can we make a
mosquito zapper lazer with it?

~~~
Kliment
You could probably, it wouldn't work very well. Either way, Nathan Myhrvold,
evildoer and all-around asshole, would sue you for patent infringement. I
recommend making a Myhrvold zapper laser first.

------
joshdance
Love this idea. However 94% accuracy is not good enough. You need to be able
to trust your action will lead to the desired result. 94% is like Siri getting
your whole text message right, but getting the recipient wrong.

~~~
tzs
A lot depends on what happens the 6% of the time it fails. If failure just
means that it fails to recognize that there was a gesture, then 94% is
probably fine. It's not that big of a deal to have to gesture twice 6% of the
time to turn off a light or skip to the next track.

Failures where the gesture is recognized as another gesture would be a lot
more annoying.

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pointernil
Just wondering, do standard wi-fi chipsets provide the raw signals needed to
implement things depending on spectrum-analysis like this? Some super-raw
mode? How about Bluetooth chips? Sound chips (for supersonic)?

~~~
pointernil
it should have been "ultrasound" instead of "supersonic" ;)

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waster
Great; so next time I sneeze, I'll accidentally turn on the garbage disposal?

Seriously, though, it reminds me of the "house of the future" from one of
those ubiquitous films they showed us in elementary school way back in the
day.

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cheald
Honestly, the most exciting aspect of this would be in being able to just have
a passive scanning system that can identify where in the house my kids are.

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mathiasben
Could be useful in prisons to keep tabs on the general population without
having to use cameras.

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protolif
This may not be something we want.

~~~
regularfry
It's going to happen anyway.

~~~
moron4hire
probably not, home automation has been "right around the corner" for 60 years.

~~~
freehunter
Home automation exists and is cheap. There's a huge niche industry built
around it. The problem is that people don't actually want it as much as they
say they do. That doesn't mean it doesn't exist.

~~~
TeMPOraL
I think they are still a bit too expensive for people. You can either get a
whole system for several dozen kUSD, or single elements (e.g. smart outlets)
for ~$100 each. The former is a significant expense people might not want to
pay at once when buying homes, and the latter is a bit too expensive to buy
one by one, because you require to have at least few of those devices before
the system starts to get useful.

~~~
freehunter
It's not nearly that expensive, though. A light socket is in the neighborhood
of $15. A wall socket is less than $25. A transceiver is $30. For just over
$100 you can get the controlling software, two wall switches, two light
sockets, and a transceiver.

[http://www.thehomeautomationstore.com/x10-home-
automation.ht...](http://www.thehomeautomationstore.com/x10-home-
automation.html)

~~~
chopsueyar
Oh, but don't use CFL bulbs with those wall switches or light sockets.

...and good luck determining whether the device is on or off.

~~~
freehunter
That's not the point, and there are units which address those concerns. The
point is, home automation is not "right around the corner", it's here today
and it doesn't take a millionaire to have a smart home. The sticking point is
not technology nor is it money, it's that people have realized they don't
really want that.

~~~
chopsueyar
The technology you refer to has not changed since 1975.

It is a stretch to call this smarthome technology considering the ban on
incandescent bulbs, which completely eliminate X10s ability to dim or fade
bulbs (because you are using CFL, and if you use a x10 dimmer on a CFL, you
can burn down a house), and writing any sort of logic based on whether the
device is on or off is not possible.

Now Insteon supports bi-directional communication and you can determine state,
but you are looking at $45 per outlet or switch versus the $8 X10 stuff.

So, yeah, still out of most people's price range, unless you want to settle
for over 30 year old technology.

------
fbeeper
I'm nowhere near to be techno-apocalyptic, but I just thought that from a
"1984" point of view it could be a tool to monitor activities without no
permission at all.

~~~
rz2k
And wearing a tin foil hat just makes you a better reflector!

Anyway, if you look up through-wall radar detection, most of the
implementations use S-band radar, and it is probably safe to assume that it's
already been figured out how to use wifi stations and devices already in place
emitting signals to each other, rather than always needing to bring additional
equipment.

With regard to privacy though, it seems like it would be data and
computationally intensive to track the movements of people in a large number
of houses.

Let's say that a hypothetical application could only detect velocities away
from or toward the base station, but no directional information. With each
movement you make it would build a set of hypotheses about your location. Then
when you make another movement, it would need to branch out, and create an
entire set of hypotheses for each hypothesis in the previous set, and so on
with each movement. While the program could abandon entire branches when they
showed you walking through a wall, it would still grow very quickly.

Though it is possible to mine data of cell phone locations and CC television
cameras after the fact, it seems like (if my understanding of how the
technology would work is anything near reality) it is simply too difficult to
collect a lot of information about people's movements in their homes without a
specific prior reason to justify the expense.

Anyway, perhaps rather than tinfoil hats, people worried about surveillance
should hang lots of mobile sculptures in their houses to create confounding
noise instead.

------
pavel_lishin
This strongly reminds me of A Deepness in the Sky, albeit the implementation
is different and the resolution is probably nowhere near the fictional stuff.

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znt
If used right, this would disrupt home security industry so hard. It would be
possible to get rid of any motion detectors, if I am not mistaken.

~~~
jlgreco
If I understand this correctly, you would really be replacing one sort of
motion detector with another.

The article is talking about phased array stuff, stuff you can't do with stock
wifi equipment. All the regular wifi equipment is just providing the "light"
the special receiver needs to see.

~~~
hughes
So really, it would make it _im_ possible to get rid of motion detectors. You
could never really be sure that one isn't nearby.

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cdooh
This is so cool!! I wonder how far off it is to commercial deployment and what
licensing plans they may have.

------
bakztfuture
How would you get started with this technology or stay updated with this
project? I'm keen on its prospects.

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Yuioup
Bye bye Kinect. Guess we won't be needing you now.

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aren55555
They are tracking all our movements via Wi-Fi

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alphanumeric0
Damn, I posted this on hacker news before you.

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trendspotter
It is now on Techmeme, too: <http://www.techmeme.com/130605/p19#a130605p19>

~~~
simias
What is is, why do I care?

Or are you just spamming?

