Using Wi-Fi To Count People Through Walls (techcrunch.com) 26
An anonymous reader shares a report: Whether you're trying to figure out how many students are attending your lectures or how many evil aliens have taken your Space Force brethren hostage, Wi-Fi can now be used to count them all. The system, created by researchers at UC Santa Barbara, uses a single Wi-Fi router outside of the room to measure attenuation and signal drops. From the release: "The transmitter sends a wireless signal whose received signal strength (RSSI) is measured by the receiver. Using only such received signal power measurements, the receiver estimates how many people are inside the room -- an estimate that closely matches the actual number. It is noteworthy that the researchers do not do any prior measurements or calibration in the area of interest; their approach has only a very short calibration phase that need not be done in the same area." This means that you could simply walk up to a wall and press a button to count, with a high degree of accuracy, how many people are walking around. The system can measure up to 20 people in its current form.
Wifi has to much overlap to jam up channels with t (Score:2)
Wifi has to much overlap to jam up channels with this
Ethical Implications (Score:4, Insightful)
If I use this to spy on my neighbors and find out they're being periodically abducted by the Asgard, should I tell them?
Joking aside, the accuracy is around 2 people, and it can't tell you anything about distribution. So on average, you have no idea if there are people or not. But you can tell a crowded room from an empty room, at least in rooms that if empty would have a normal attenuation pattern.
Pretty weak sauce. Old-school DIY radar on the same frequency is generally more accurate than this.
Re: (Score:2)
I can do better, and recover audio with a paper cup against the wall!
If they are using multiple frequencies (Score:2)
could they get better granularity? I'm thinking 2.4 and 5.0 ?
My house has thick enough walls that it would probably be difficult to discern much, unless someone floated a drone above it.
Clickbait (Score:3)
It doesn't matter how much power you transmit outside a room, the received signal AT THE TRANSMITTER is not going to be attenuated by the people in the room. In fact, the received signal will depend ONLY upon the transmitted signal level -- the receiver and the transmitter are connected to the same antennas.
This is patent nonsense.
Re: (Score:3)
The receiver and transmitter are not using the same antenna. They are on opposite sides of the room.
From TFS:
From TFA:
A single Wi-Fi router outside of the room cannot be on opposite sides of the room. A single Wi-Fi router outside the room likely has a pair of antennas, but they are separated
Re: (Score:2)
From TFA, quoted from the original release:
The transmitter sends a wireless signal whose received signal strength (RSSI) is measured by the receiver.
The original release [ucsb.edu] says:
In the team’s experiments, one WiFi transmitter and one WiFi receiver are behind walls, outside a room in which a number of people are present.
In fact, why not just read the paper itself [ucsb.edu]?
our experimental setup consists of a
pair of WiFi nodes for transmission and reception of wireless
signals. One of the WiFi nodes is configured as a Tx, which
constantly transmits wireless signals. The other WiFi node,
which acts as a Rx, measures the signals that are emitted from
the Tx node and records the corresponding signal strength
It would've taken much longer to write out your rant above than to spend two minutes locating the paper and bypass all the misinterpretation.
Re: (Score:2)
In fact, why not just read the paper itself?
Because the clickbait had no links to any paper. Only the claim that it was using ONE WiFi router.
Yes, if you put TWO routers on the opposite sides of a room and measure the signal between them, you will measure how much attenuation there is, and you can assume it comes from people. This is true for almost any two radios, and isn't specific to WiFi. Use a pair of bluetooth devices, or something at another frequency. Hell, do it with ultrasonics. Bodies absorb that, too. Do'h. But then, you can't just walk
Re: (Score:2)
I don't think you get many points for being correct about something not relevant to the subject. Yes, science reporting sucks at a lot of popular sites, we know. And given the rest of your comments, it sounds like you still haven't read the paper, which is somewhat less obvious than you appear to think.
Re: (Score:2)
I don't think you get many points for being correct about something not relevant to the subject.
The summary and the news article it links to are probably relevant to the subject. If not, why do they exist?
And given the rest of your comments, it sounds like you still haven't read the paper, which is somewhat less obvious than you appear to think.
Path loss is established science. My points stand.
Re: (Score:2)
Here's how I got to the project page:
Played on the video.
Clicked on "YouTube" to open it on YouTube.
Opened the description.
Clicked on the project page.
An error in understanding doesn't translate to clickbait, and getting to the source isn't that hard.
Re: (Score:2)
An error in understanding doesn't translate to clickbait,
Deliberate misrepresentation of the material to make it seem magical and new does translate to clickbait. Linking to a page that is 90% advertising, which automatically changes to an irrelevant page with 90% advertising when you scroll just a skootch past the clickbait article is clickbait, especially when you cannot go back to the original page using the standard "back" button.
and getting to the source isn't that hard.
You have to watch the video, which doesn't play well over the net to begin with and not at all when it isn't in a form that is pla
But not on Faraday cages (Score:2)
For some reason, that doesn't work.