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WiFi can read through walls (ucsb.edu)
251 points by geox on Sept 11, 2023 | hide | past | favorite | 171 comments



PSA: Nokia is out there pitching a vision for what 6G mobile networks will look like, and they're pitching this as a _feature_ of the media.

Nakia wants 6G devices to act as 3D imaging clients, and for network operators to have access to a realtime, 3-dimensional visualization that can see right through walls.

this was literally used as a plot point in one of the batman movies a decade ago to highlight how dangerously invasive tech can be.

https://www.nokia.com/about-us/newsroom/articles/nokias-visi...

https://www.bell-labs.com/institute/blog/building-network-si...

> A very exciting innovation that 6G will bring to the table would be its ability to sense the environment. The ubiquitous network becomes a source of situational awareness, collating signals that are bouncing off objects and determining type and shape, relative location, velocity and perhaps even material properties. With adequate 6G solutions for privacy and trust, such a mode of sensing can help create a “mirror” or digital twin of the physical world in combination with other sensing modalities.


> this was literally used as a plot point in one of the batman movies a decade ago to highlight how dangerously invasive tech can be.

In the movie Charlie’s Angels (2000) the supervillain technology allowed them to track the locations of the vast majority of people on the planet in realtime.

The real world has already jumped the shark for many different fictional supervillain doomsday technologies.


I had a discussion with my church group about this and it was absolutely fascinating. On the one hand they welcomed the ubiquitous observation and judgement of all people, because they thought that would make it easier to control people's behavior. But also someone pointed out that is what the anti-christ would do. In the end there wasn't any real consensus on whether or not mass surveillance was good or bad.


Did the church group not already believe there to be an entity capable of ubiquitous observation and judgement of everyone, that as an added bonus happens to be entirely benevolent? I'm not sure how any human-made competition in this department could be beneficial.


This is indeed a big paradox in organized religions.

When I was young my parents wanted me to learn about religions so I could make my own choice about which to follow. But I was constantly like "wtf how does this make sense???". And disruptive in class :) They had to take me out of Sunday school.

Another thing I never understood is predestination in calvinist religions, which are big in Holland. They believe it's already decided whether you go to heaven or hell, regardless of your actions during your life.

So how would you live your life? Personally I'd go for maximum enjoyment because whatever happens is already decided. But no, they're very strict and regimental in general. Never understood why. But of course I did only have Sunday school for a short while :)


> Another thing I never understood is predestination in calvinist religions, which are big in Holland. They believe it's already decided whether you go to heaven or hell, regardless of your actions during your life.

> So how would you live your life? Personally I'd go for maximum enjoyment because whatever happens is already decided. But no, they're very strict and regimental in general. Never understood why. But of course I did only have Sunday school for a short while :)

I heard about the predestination thing well before I heard of Newcomb's paradox, but now I realise this is basically the same as "one box, or both boxes?"


That's terrifying that people thought it was potentially good


Why do your fellow congregants want to control the behavior of others? Why can’t they just focus on their own lives and their own community instead of what other people outside of their community are doing?


Not OP, and I can only speak for the circles I grew up in, but some churches are full of deeply traumatized people. I think some of the authoritarian tendencies have roots in a deep desire/need to regain some kind of feeling of control in their lives, and here’s this group of people that meets every week who provides a level of comfort and community while offering a gospel that can both satisfy that need while making people feel righteous in the process.

I don’t want to doxx myself so I’ll keep the details vague, but both of my parents came from disturbing environments and were subject to things that would universally be understood as deeply traumatic. I think they’re good people, but very very confused, and their fundamentalism was a product of the degree of unresolved trauma/dysfunction in their lives and their need to impose some kind of order on their circumstances.

Not all churches look this way. Mine sure did. Almost everyone had a story. Thankfully I escaped the bubble. But not without consequence. Through no fault of my own, I was indoctrinated into a belief system that I then had to spend decades and counting unwinding and unlearning. I mention this because a lot of people want to focus on other people’s lives because that’s what they were taught to do. People were born into beliefs they didn’t choose.

None of which is to excuse the behavior. But I’ve seen up close where it comes from.


Thanks for sharing your story. Mine is similar. Always interesting to see someone else take this life path.


It’s an interesting path for sure. I’d never wish it on anyone, but the experience has also been useful in its own way.

Email me if you ever want to chat about this stuff.


You may not be paying attention. A decent slice of the population wants the government to control everything, all of the time. These people are all around you, all of the time, no matter where you are.


This assumes quite a bit about the group. Is it wrong to discuss topics like this and share different views? Why do you want to control this groups private discussions?


You are correct that I am making assumptions, I’m assuming this group wants to control the behaviors of people outside of their religious group which may not be the case.

I don’t want to control their discussion, it’s fine to discuss things and share different views. I want to understand why a group of people would welcome a panopticon because it would make people easier to control.


I agree it's a bit of a strange dialogue at church, but there is an emphasis on pius behavior both in public and private so I would guess this is the line of thinking they were going down. I would grant the other commenter that God doesn't need 6g to see you, if you believe in that.


I don't think the parent is controlling the discussion, or really even saying it's wrong to discuss this and share their views. But, by the same token, the parent is also allowed to express their concern about people who do hold these views here.


I think they implied observing the behavior of fellow congregants not outsiders. Not sure if that makes it any better. But I think that’s what the poster meant.

That said it is definitely what any competent authoritarian would want.


Why should they control the behavior of people in their congregation? I associate controlling the members of your own community with cults.


Last time it was the end of the Aries age, when Nero played the role of the antichrist. Today we're approaching the of the end of the Pisces' age, and Nero 2.0, fixed and engrossed, will be equipped with brain reading devices (the future of neuralink), machine intelligence and human-like machines. Thinking in private will be possible only at the abstract level, as all the internal monologue will be carefully recorded and analyzed. He will rise to power on the wings of nihilist technocrats, and will institute the law for those who want to be free, and freedom for those who want to be free from the law.


US govt and military give a lot of money to Nokia


Nokia has NSA rooms in their R&D offices. It's creepy.


They revealed that publicly? (Do you work for Nokia? (or the NSA?))


I think it's a misunderstanding. I found a couple of articles mentioning both Nokia and NSA, but here NSA stands for "Non-Standalone 5G network".

Here's a press release, for example: Nokia selected by Dedicado for 5G NSA network in Uruguay (https://www.nokia.com/about-us/news/releases/2022/12/08/noki...)

And a Linkedin profile (he must have a room in the office): Yuriy Pavlov - NSA Infrastructure Information Systems Manager. Nokia. (https://www.linkedin.com/in/yuriy-pavlov-1969904)


If he does, he probably does not anymore.


What's even creepier is that parent company also owns Github.


Microsoft purchased Nokia's Devices & Services division, and rebranded it as Microsoft Mobile. Nokia then pivoted to telecommunications infrastructure and IoT. So there's no longer a relationship between the two companies.


Also, the Nokia smartphone brand is licensed to HMD Global.


Yeah someone at Microsoft thought they could get Windows CE to run on the popular Nokia 3210. /s


ahh, the golden days when the smartphones that mattered ran Symbian and we thought Elop was going to be our Elon.


N900 ran linux and it mattered


Microsoft?


My understanding is that the 3D imaging is somewhat inherent to how the protocol operates: higher frequency data over a wider band of frequencies means they can locate you more precisely.

Cell phone network operators need to know your location in order to route traffic to the correct tower in order to reach you, and that is not changing anytime soon. Same principle for WiFi beamforming.


It's deeper than that. You can't have advanced communications without gleaning the information needed to form a 3D image.

To get maximum data throughput, modern communications systems measure how the channel (ie. environment) changes the radio signals and then reverses those changes in the receiver. (search term: channel estimation). So it's inherent that a modern communications system is modelling its environment. A primary way communications systems become better is to increase the sophistication of their environment model.

Once the model becomes sophisticated enough, the only difference between a radar and a communication system is which information you choose to extract: the information the environment imprinted/modulated on the radio signal/carrier (ie. the model of the environment) or the information the transmitter imprinted/modulated on the radio signal/carrier (ie. the message). The first is radar, the second is communications. There is no technical reason why you can't extract both.


This is not a technical question but a moral one in the face of such surveillance apparatuses as exist today.

A pen can be both a writing implement and a deadly weapon. But until someone decides to use it as a deadly weapon, it's not one. Luckily we don't typically hear people explaining the anatomy of soft tissues in the human neck when talking about pens.


Except you can't mass kill people with pens. Or you can't hijack someone else's pen and kill them. You can mass surveil people with this tech and you can be sure it will be used that way sooner or later.


Sooner, most likely.


Agree. Hence the qualification that there is no technical reason why the information can't be extracted. Any barriers are non-technical.

The problem is that this information is inherent to a communications system. It can't be separated. Communications is pervasive, so channel information is pervasive. How does one control something that is pervasive?

It's a Catch-22: Do we implement a surveillance apparatus to prevent people from accessing the channel information that can be used to build a surveillance apparatus?


> Do we implement a surveillance apparatus to prevent people from accessing the channel information

thats the wrong question - simply remove all barriers that prevent consuners from inspecting inner working if their devices, and attach large statutory compensation in case a consumer privacy is violated.


Killing people isn't a typical side-effect of normal usage of pen, unless you want to go into comparing might with swords.


I had an app that ran on Android about a decade ago, which let the user ignore some of the cell masts, so you could not be triangulated, it let you stick to just communicating with the cell mast of your choice.

Dont know if its still around.


Not just to the correct tower, but also for adaptive beamforming.


> Cell phone network operators need to know your location in order to route traffic to the correct tower in order to reach you, and that is not changing anytime soon.

But that's obviously false. They can know which tower to route your traffic to by the simple fact that that's where your traffic came from.

They know where you are because you broadcast simultaneously to all of their towers, but that's not something they need.


That assumes a stationary target. As cell sizes shrink due to higher frequencies, the need to anticipate where you are and where you're going goes up.


Well, because it is a feature. It's really cool and I already have ideas for projects I want to do with it. An omnidirectional way to map an entire space that doesn't have the limitations of or require cameras is incredible. And one that I can potentially use to map myself as I walk around. It's basically the end game of motion controls.

The popularity will explode the moment someone makes a commercial where someone is cooking with something messy and using their phone without ever touching it.

It's the people who make or break it. "This technology is too dangerous and must be destroyed, but hold on I need to use it first because it's really useful" doesn't feel like the strongest condemnation.


The only result will be that the router of my neighbor, provided by his ISP, will happily reports the inside of my apartment. Sorry, I can be excited for a radar-based controller for a console, but as part of wifi, I can't really find any legit use


Beamforming around moving (or even static) obstacles? Integrated motion sensing with fewer false positives for smart bulbs, doorbells, whatever? Or more realistically, your TV can make sure you don't skip the commercials. I probably wouldn't use that stuff myself either, but it's interesting to think about.

Why would I care that my neighbor knows we're home and moving around? If they really wanna creep on us, they can already use IR cameras or audio amplification or laser mics or whatever.


Walls of homes are usually insulated enough to make an IR camera useless unless it's inside the home. It would be good for identifying cracks that heat can seap through though. Surveillance by laser microphones can easily be mitigated by curtains or blinds. Both of those also require the person spying to intentionally use them to spy. There is no legal commercial device that could prevent your neighbor's Xfinity Hotspot from selling what you do in your own home to Facebook/Google to use to target you with ads.


It would come off as a bit paranoid, but chicken wire would block wifi signals.


It is commonly used for older plastered facades. Maybe there will be a resurgence.


It’s used for stucco as well, which is everywhere.


> If they really wanna creep on us, they can already use IR cameras or audio amplification or laser mics or whatever.

There's always a more sophisticated way to do something bad. Why would that be a good reason to lower the bar for doing it?


This is the first time I've seen someone use this question in defense of privacy, instead of against it.


I, maybe naively, assumed this capability will also comes to handhelds but yeah if it's only for stationary APs then it's kinda lame.


surveillance into private places is illegal. you can't film in someone's window, you can't wifi vision through someones walls. whether or not that is prevented from happening by manufacturers and that the law is enforced depends on a lot of things


You can take infrared photos currently of someone's house and use that in court


with a warrant many kinds of search are possible. in normal circumstances, that's illegal


The problem is not that you can buy a device that does this. The problem is that they'll put it in devices you can't easily avoid buying, don't control the firmware of or which have an abominable security record.

It's fine if I can take live 3D radar images of the inside of my bedroom. Not fine if someone else can.


It's not just Nokia, basically everyone working on 6G proposoals is working on this under the name joint communication and sensing.


Its interesting that any time where someone can gather some form of data is now labeled as "privacy invasion"

Which makes the whole discussion about privacy a joke because nobody can define what privacy is.


> Its interesting that any time where someone can gather some form of data is now labeled as "privacy invasion"

.... I think technology that enables visualization through walls is pretty obviously a privacy invasion. People are used to walls giving them privacy...


IR cameras existed for quite some time. You can also locate people through walls with sound.

Simply by going about your day you publish metadata about yourself that can be used to derive behavior.


This is not (completely) new. 2019 paper entitled "Passive Radar based on 802.11ac Signals for Indoor Object Detection":

* https://ieeexplore.ieee.org/document/8904842

There is an IEEE Working Group to create an extension for 'active radar':

> IEEE 802.11bf will enable stations to inform other stations of their WLAN sensing capabilities and request and set up transmissions that allow for WLAN sensing measurements to be performed, among other features. WLAN sensing makes use of received WLAN signals to detect features of an intended target in a given environment. The technology can measure range, velocity, and angular information; detect motion, presence, or proximity; detect objects, people, and animals; and be used in rooms, houses, cars, and enterprise environments. The targeted frequency bands are between 1 GHz and 7.125 GHz (MAC/PHY service interface) and above 45 GHz (MAC/PHY).

* https://standards.ieee.org/beyond-standards/ieee-802-11bf-ai...

Presentation on the extension and Wi-Fi sensing:

* https://www.youtube.com/watch?v=I3GmgO9biH87&t=5m10s


It is novel in terms of using physically accurate models such as edge diffraction to localize edges instead of the object as a whole. Most narrowband radar based imaging approaches consider extended objects as a collection of omnidirectional point scatterers, which may not be the most optimal representation....


Yes, I have met technologists who claimed to be working on the tracking of people in their homes using Wi-Fi. There are great uses such as elder health monitoring (i.e. not fallen and can't get up) but others too...


I remember seeing some presentations about WiFi gait recognition too. Quick google turned up this __2016__ paper

https://dl.acm.org/doi/10.1145/2971648.2971670



Man, I'd settle for wifi that just lets me internet through walls reliably.


My simple 5yo, non-wifi6 router gets me a reliable signal through at least two walls, so I would imagine any somewhat modern router would meet your requirements.


In all seriousness, it depends on your frequency used, building materials, national limits on WiFi output power (which some routers/firmwares respect more than others), etc.

5 GHz in particular has trouble passing through concrete and metal. If you have a small wood house or apartment it often isn't an issue, but if your office has a lot of concrete and steel, etc. it could be problematic. Those enterprise mesh networks exist for a reason :)

https://blog.ibwave.com/a-closer-look-at-attenuation-across-...

https://help.keenetic.com/hc/en-us/articles/213968869-Wi-Fi-...


The metal mesh in some plaster walls seemed to cause a lot more signal drop than I expected in one place I lived.

5GHz was basically a no go. It wasn't a huge loss since few devices were running it back then.


When I was in high school, my parents hired some contractors to put an addition on the family home and do some improvements in most of the rooms.

So the most arduous part of the whole job appeared to be the demolition to start with. They started pounding into the thick plaster walls, and revealed a thick mesh of solid steel reinforcement. Of course, that took ages to take out, wherever they had to deal with such a wall.

And you know what? I was absolutely appalled by the chintzy material that went in to replace it. They just brought this drywall, you know, and I got to touch it and examine it, and I couldn't believe how flimsy it was, when compared to the reinforced plaster they'd just taken out. I mean, like, there were cost and time considerations, but it seemed like a travesty to me. Like we were sacrificing half of our solid, valuable home for a mere facsimile in the other parts.

Today, the WiFi is fairly bad. My dad only has the one router in a distant corner of the den. I don't know how reception is directly upstairs, where his bedroom is, but the downstairs bedroom can barely keep a signal going at the best of times.

That home renovation was happening around 1988, so possibly too early to really think of putting Ethernet in every room, but my dad would've been the dad to do it.


Sure, the drywall is flimsier than the plaster walls you had before but they are way easier to work with, make modifications to, and repair. And for normal usage, they're plenty reliable. The walls themselves shouldn't be a part of what makes the house "solid", that's the job of the framing behind the plaster or drywall.


> The walls themselves shouldn't be a part of what makes the house "solid", that's the job of the framing behind the plaster or drywall.

It's actually a fairly recent trend to not build load-bearing walls anymore and instead really on a skeleton. Walks can very well be constructed to be load-bearing. But, as you indicate, the resulting building would be more difficult to modify.


It's also, typically, nailed into studs 16" apart. Just not a lot of room for flex in that case.


> They just brought this drywall, you know, and I got to touch it and examine it, and I couldn't believe how flimsy it was, when compared to the reinforced plaster they'd just taken out.

Exactly what are you getting by having the 'less flimsy' plaster and what are you losing with the 'flimsy' drywall? (I ask this as someone with three uncles that work in construction/renos.)


The biggest benefit I've noticed with plaster walls is the soundproofing. There's more layers of much denser material.

My walls are 1 inch of plaster with metal lath (vs the typical 1/2 thickness for drywall), on top of traditional wood slat lath, then insulation and studs. Typically if you have construction old enough for lath and plaster walls, they might also have independent studs per side, further isolating sound transfer.

It's also less porous and doesn't hold water like drywall, making it quite mold resistant.


My very modern many antenna WiFi6 router has a very hard time going through even one wall. Turns out metal lath and plaster walls do a very good job of blocking radio signals.


wooden lath and plaster the same. I assume it is the plaster, not the lath.


But not through the neighbors walls preferably to not interfere with each other's wifi strength...


use 2.4g + mesh. better yet, yet ubiquiti unifi dishes (3 would suffice for 2000sqf house).


I just ended up dragging a long ethernet cable along the wall. Gigabit that's always reliable... wifi never feels even remotely as fast or stable.


Same here, working on cat7 for the entire house.


Related:

2013 - gesture recognition from Wi-Fi https://wisee.cs.washington.edu/

2013 - see through walls with Wi-Fi https://people.csail.mit.edu/fadel/papers/wivi-paper.pdf

2023 - dense pose estimation from Wi-Fi https://arxiv.org/abs/2301.00250


'read' is misleading. It's determining what letters are represented by 3-dimensional letters.

It can't read 2-dimensional print on paper. Now that would be a massive (and terrifying) accomplishment


Yeah it was kind of misleading/clickbaity that they worded it that way. I guess they wanted to highlight how sharply they could image the room.


Somewhere.. Someone.. Who wrote down their wifi password, on their fridge, with giant 3d magnetic letters, is shitting themselves right now./jk

Interesting paper though, I wonder what non-infosec applications it might have.


What about a QR code that guests can scan to log into your WiFi without typing an explicit password.


Unless I'm misunderstanding you, this already exists: https://qifi.org/

Format is described on the page if you want to do it manually.

Of course the plaintext password is still encoded in the QR code data, so it's not very secure, but great for home guests.


On my Android Samsung Galaxy, when I want to know the password of a saved Wifi, I generate a share-QR, screenshot it, and have a QR scanner scan the picture to extract the password. It drives me nuts, the password is clearly not secure/protected, still the UI will only give me the QR code, not the plaintext. PLEASE tell me I am just too stupid to find the right menue!


Yeah, it's annoying. On my Samsung phone I have a "save image" option, which I can then view the photo in Google photos which has the Google lens option that will show the password.


On my pixel I get both qr and password.


I prefer https://mywifisign.com/en for the modern-esque background and verbiage.


Hey! This happens /s


You ever finish working on something and then think to yourself, "damn, I just created something incredibly evil"?


3-letter agencies have reportedly been using RF for similar purposes for almost a decade https://www.usatoday.com/story/news/2015/01/19/police-radar-....


So we agree it is evil then


I was working on a IT consolidation project in a remote country branch, replacing the old systems with those of the global IT infrastructure and a new local server managed by the global IT team. When I finished my work I was standing in the small servers room with the local IT admin, he said something that disclosed he felt there was nothing important for him to do anymore. The move was the right path for the business. I felt terrible.


How many steps removed is a bad actor from making it themselves?

Usually, we can't rely on things simply not being invented, so we do the next best thing: invent it, and use the invented thing to learn how to manage the risk that thing introduced.


That's not secund best. You can not invent it in the first place too. We have intentionally throttled recombinant DNA research for decades.


What recombinant DNA research do you believe is not being done?


Go find me the papers showing me it is. You can't ask someone to prove a negative.

Here's another one: name the private (not gov contractor) orgs who are currently working on fission/fusion or even radiological weapons. There aren't any. For as disparate as the cultures of China and the US are, both realize the fact that DIY nukes are bad and universally disappear anyone going down that route.


You can also make it illegal, like private-sector research into nuclear bomb development.


Ethics really should be mandatory for anybody making/designing anything. Some unis do fortunately have mandatory ethics courses depending on your programme.


Ethics is (often?) required in engineering curriculum, but it's mostly along the lines of "don't lie about work you didn't do then charge for it". There's nothing that touches on only using your powers for good. Like building 'autonomous' cars then letting them loose in public before they're proven, or building out algorithms designed to get people addicted to rage bait, or building in planned obsolesce, or building a device that uses WiFi to map out a private domicile without the occupant's knowledge.

Engineering ethics courses all boil down to "don't lie about stuff", not "think about the potential consequences of what you're building".


Bold of you to assume that anyone will care about what they heard in ethics class when presented with the opportunity to get rich and powerful.


I accidentally created a 200 loc bossware with PythonCV that reported if I was in-front of my computer's webcam to a dashboard with videofeed, for a sales meeting with Microsoft were we were supposed to show we could do stuff. I shit you not. I was so proud that I could encircle my face with a square that I didn't consider the obvious use case for it.


Very impressive! Famous previous work captured moving objects and did gesture recognition through the walls https://people.csail.mit.edu/fadel/wivi/project.html but this new research can capture still objects.

UCSB paper: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=101... ("Analysis of Keller Cones for RF Imaging")


Already exists in prod. At a meetup several years ago, it was demonstrated that you could track a person’s location in an adjacent room by triangulating Wi-Fi interference.

I’m not into RF so this is a bit imprecise, but it took like a RPi with GNU radio, a second router, and some code to diff the signals into a location.

The demos were compelling, you could see a heatmap of a user waving and so on. This is a product already sold.


The page, paper and video say that as well. The difference here is that this is tracing still objects.


One of my customers referred me to this thread. We have been developing our NED Passive Radar technology for 5 years now, and have field deployable, vehicle mountable, drone mountable, and pocket sized, rechargeable passive radar RF datalogging systems you can use to locate and identify devices of interest, such as drones, cell phones, wifi and bluetooth devices. You can image the environment in 3D via ambient RF emissions using our spherical antenna arrays. Basically right now our systems log raw RF signals from SMA connected antenna arrays to a micro SD card in .csv format, or you can stream it realtime via the usb port to a computer and use our python library. We have model with 4 RF ports that senses from 2 MHz to 10 GHz, and a second model with 10 ports that senses up to 84 GHz. They are quite affordable also. Its great to see the interest in this area, if you would like more info or want to try what we have come up with contact us at www.xadite.com


Impressive. Now how do we defend against malicious use of this POC?


This is what I use: YShield RF Shielding Paint - 5L Bin - HSF54 - Blocks Wifi, Smart Meters, Cell Phones, Etc. https://a.co/d/csJJslD


good lord. that's cool, but wow would that be expensive. did you only use this on the exterior walls of the house? how much primer did it take to get the paint to match the rest of the walls? also, what about windows?


I did it inside my bedroom, ceiling and all walls because we are fairly close to a cell tower. The rf meter I have went from 3000-5000 down to 7-10. I can't type the symbols in my phone for the units. Better sleep for sure since doing that a couple of years ago.

Windows we used film, curtains shielded too. Two coats primer. Put copper stripts to ground as well on walls before paint. Didn't do floor so some rf gets in and out which is ok actually, you can create a focusing effect if you aren't careful about it.


Do you sleep better because you're not on your phone so much? I've heard that you should avoid screens in bed.


I don't seem to wake up as much in the middle of the night


so what is it about radio waves that you feel is disrupting? my only reference to this is the Chuck McGill character from Better Call Saul


Oh man, that's a rabbit hole. I always slept better at my parents cabin. They eventually got wifi and I stopped noticing any difference. Then tried an emf shielded top and it worked really well. Then did the paint on the walls of bedroom.

If you want science, it's tough, nobody is going to fund it and it's harder and harder to find a control group.

There's studies of dubious quality if you Google emf and sleep.


A couple questions —

Could you link to the film you used, and also the curtains?

Did this at all block your ability to use your own cellphone?


It was a 3m film, the curtains were just emf fabric sewn in the back of regular curtains and they block the light more. And yes, Wi-Fi and cell still work, we left floor untouched. I can no longer pick up neighbors Wi-Fi in that room. My neighbors are about 150 m away, rural. I turn wifi off at night in my house.


How well does this work? Always sounded to good to be true to me.


The paint itself probably works well if it's conductive - it's just a simple Faraday shield. The problem is with testing. For example most Faraday pouches and bags turn out to be snake oil upon testing, as they let the signal out through some discontinuities, even though the mesh itself works perfectly and most of the time you don't have the signal.


Do I sense a future asbestos-like scandal brewing here?


What evidence are you basing that on?


I would start by not building your password out of giant metal letters.


I was thinking of plain old spying by identifying presence of people, perhaps enough characteristics to determine who it is.


How else am I supposed to keep track of it?


Noise/Jamming. Signal/Timing Spoofing. Environmental Spoofing. Also anyone using it paints a giant target on their back. These are all true of any active signal imaging system.

Somewhat related but I always thought a cool warfare device would be a grenade that contains an inflatable "soldier" with a built in heat signature. Toss them around for IR imaging spoofing.

Anyways..


Leave the microwave running


Build a detector which can differentiate from normal traffic and a "scan" like this.

Wire up an RPI to a motor which reorients a 2.4ghz parabolic dish, first discovering the direction and elevation which best picks up the signal from the "scanner". Then, engage the old microwave emitter you've hooked up to the dish.

You will like as not fry their equipment. Bonus: the attacker may never have children.


That's the best part of it: the technique seems to be passive.


Fry everything then.


Wouldn't you need two microwaves for each axis (XYZ), facing opposite direction? So six microwaves in each room. You have to remove the door switch because you need to leave them running 24/7.


let's not be silly. just put it in the attic so each room is covered centrally. you may need a higher wattage microwave though.


Mine is around 800w. Would a single 1600w be as good in the attic centre as two 800w evenly spaced?


This all makes me wonder on the efficiency of the original idea. if you have 6 microwaves oriented in each of the directions of an XYZ plane, there would be the assumption that the coverage would be radiating out so there are no gaps in coverage. You could then rotate the rig, but that gets complicated for all 3-axis to rotate. But if you're rotating, then why not just one for each axis. Also, is the axis pointing at the ground even necessary to radiate?

So now we have to consider the wattage of a rotating system, and how fast does it need to rotate so the time not directly being radiated doesn't cause gaps in coverage. There's a lot of variable to cover here.


Tinfoil


Ask the Amsish


i don't think being unaware protects you.


"Integrated sensing and communications". This is what 5G/6G+ are all about. This is what powers "internet of things", "smart cities" and "total sensor fusion". This is why The Five Eyes cautioned legislators about Huawei 5G infrastructure.

https://link.springer.com/book/10.1007/978-981-99-2501-8

https://www.youtube.com/watch?v=aaaLl_5kUQE

https://www.youtube.com/@integratedsensingandcommun7276


Hopefully we aren't documenting company/government secrets with letter blocks that you purchase at Hobby Lobby.


"oh look there's the FBI guys again. Go get the giant foam typewriter letters from the back room. "


at least they a decent enough to drive around with SSID labeled "FBI Surveillance Van", so you just need to have an RPi scanning available SSIDs, and enable the SCIF-activate button when the van approaches


Outline detection of metal objects at distance should be good for remote gun detection.


Could one use case be: Precisely identifying framing members (studs, rafters) behind stucco, thick lath & plaster, and roof shingles? That would be super valuable for construction work.


What are the health implications of this? Isn't that like an x-ray?

Any good research out there on WiFi, cellular and RF in general?


https://www.dia.mil/FOIA/FOIA-Electronic-Reading-Room/FileId...

This is from the DIA but was acquired via a FOIA request so I don't know how valid it is. I would probably start looking at the references first.


Wow, can I fulfill me dream of living in a 1984 style dystopia?


Get your ass to Mars.


Because Mars will be more or less of a dystopia?


I am not the one who suggested Mars, but if we interpret 1984 style as a reference to scifi movies instead of Orwell, it does fit.

The original Dune was released that year, and Terminator too...


This isn't really that different from sonar is it?


Cool another way to strip away peoples privacy.


It would be awesome to see the applications of that to assist blind people / replace vision altogether


You know, we don't have to create a tech dystopia. It's a choice. We do have some agency.


So is there an open source implementation of this yet?


What did they use as a receiver? how RX Grid was build?



Only when no one is watching.


Stupid question as someone who worked on wifi for many many years: What is the point of this? How is this remotely useful? There are tons of better technologies to use?

Let me guess, this thing puts the wifi into some constant transmit mode and measures loss rates as it passes through objects, and scans in some pattern, measuring loss rates at the other side.

Is this just packet based radar? Is this a cute way of saying "using the 5GHz band to scan through walls when you have a receiver on the other side of your object"?

Here's the thing: different materials absorb / reflect radio waves with different characteristics. You could just as easily make these letters out of a completely different material that doesn't remotely resemble a letter and it could look exactly like a letter.

How is this useful? And why is wifi the medium to do it. You can't just do this with a regular old driver. Your normal driver will be selecting antennas, adjusting rates for loss rates. This is clearly a dedicated radio with some open source driver that they've hacked to do this.

Ugh. This just seems like a dumb waste of time. This isn't even a passive radar, as it requires there to be a receiver on the other side. There is no bouncing back of signals.

"It does not require any prior RF data for training a machine learning system for RF sensing." Yes, but it does require very specific material characteristics that it is trying to detect at fixed distances. Namely edge keller cones on specific materials, and hoping that other materials don't replicate similar patterns.


Yes, essentially radar. Wifi is the medium because you already have a router in your home.

This sort of capability is being introduced into the newest WLAN standards and is being promoted as the next step towards smart homes and devices. The idea being that a standard router can be used to detect human presence, and therefore do things like turn on/off lights, HVAC, etc. This might make even more sense in the commercial space.

This would be as far as I'm aware the first attempt at doing something like this without additional hardware (mounted sensors). It should in theory lower the barrier to entry even further.

There are higher frequency variations of this that could in theory do things like detect breathing. Some people are talking about it being like the new lifeline button or baby monitor.

How well it's implemented will ultimately determine it's usefulness IMO.


Oh, hey, I knew someone who helped with research on this while I was at UCSB over a decade ago.

From the way they described the goals of their research, it wasn't so much using WiFi as radar with specially flashed router drivers doing emitting and receiving, that's just a research convenience.

The whole point is to passively detect objects using already existing WiFi signals. It's easy enough to figure out where the router is, and if the router is regularly noisy enough, the idea is they would have enough data to work with.

The research results from a decade ago was able to pinpoint and uniquely identify humans and weapons. Not hard to guess how that could be useful to the DoD.


I would love to be able to image elements inside a wall cavity: studs, pipes, ductwork, electrical lines. I don't know if it's possible with this technique, but maybe someday these ideas will lead to something like an x-ray for building structures.


You're describing a modern off the shelf studfinder. Those already use magnets, radar, and ultrasound to detect studs, pipes, and wires.


I've got a stud detector and it works like crap. But it's pretty old, maybe new ones are better.


Project Farm has a nice review and demo of many studfinders at different price points.[0]

0: https://youtu.be/sWMJhfMPWn4?si=pA--ZqeMaK_y8hfo


Just to clarify, the receivers are on the same side as the transmitters


Thanks for clarification. That wasn't immediately clear to me from the website.


We call this a monostatic radar.


One use that personally springs to mind, is if this technology is developed enough, SWAT/Rescue teams could use this to find where people are inside buildings. No need for letter-reading precision, just good enough to be easily deployable on-site and work well enough to find where people/bodies (big masses of water?) roughly are.


Hack your internet and see everything in your house could be one use?




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