Xfinity using WiFi signals in your house to detect motion

Posted by bearsyankees 6/30/2025

Xfinity using WiFi signals in your house to detect motion(www.xfinity.com)

668 points | 501 commentspage 2

transpute 6/30/2025|

Sensing is (sadly) part of Wi-Fi 7. If you have a recent Intel, AMD or Qualcomm device from the past few years, it's likely physically capable of detecting human presence and/or activity (e.g. breathing rate). It can also be done with $20 ESP32 devices + OSS firmware and _possibly_ with compromised radio basebands.

al_borland 7/1/2025||

Was anyone asking for their network to be able to sense their breathing rate? What does this enable that actually improves people’s lives?

This is the kind of stuff that pushes me to pull a Ron Swanson and throw my technology in the dumpster.

jeroenhd 7/1/2025|||

The network already could. The standardisation is just making the feature available without hiding it.

The core of the sensing technology is about improving MU-MIMO + OFDM + all the other speed tricks. Human bodies interfere in predictable ways so you need the tech to steer around that. As a side effect, you get detection capabilities for free.

In such a setup, your laptop and router already know where you are. The question is whether or not to offer it to you so you can use that information for things like home automation. Had they not made this part of the protocol, the privacy risks were just as bad, you just wouldn't be aware of them.

transpute 7/1/2025||||

Similar technology has been quietly in use for a while, with falling cost, e.g. "Inside a $1 radar motion sensor", https://news.ycombinator.com/item?id=40834349 (100 comments).

Commercialization gives consumers and regulators the opportunity to express their opinions on the sudden and unsolicited transparency of the walls, floors and ceilings of their homes and businesses.

SamuelAdams 7/1/2025||||

I tried Wifi7 at my home, but most of the benefits are lost when physical walls are in the way. Therefore I think WiFi 7 is more for commercial applications.

TSA can check your heart rate / breathing rate elevating during your walk through security.

Casinos can see your heart spike before placing a bet. If the system is digital maybe that can be synced to always deal a loss hand.

pickledoyster 7/1/2025|||

The only use case I've heard of is elderly care, where no movement might mean a person has fallen and needs help. An edge, strictly opt-in scenario that would be addressed more effectively (movement+HR+body temp) by relatively cheap wearables.

jml7c5 6/30/2025|||

Commercial use of WiFi sensing predates WiFi 7 (a notable example is Philips smart bulbs with presence detection). AFAIK WiFi 7 just includes an amendment by the 802.11bf working group to improve performance.

AzzyHN 7/1/2025|||

What's the commercial use of having this data though? Or even law enforcement use? We all have our phones on us most of the time anyways, knowing where in my house I'm at doesn't really... change anything...

transpute 7/1/2025||

There are 1000+ public research papers on machine learning + RF detection of human activity, including but not limited to breathing rate, keystrokes, body position, body motion, gestures, sleeping, biometric (identity) signals and more, https://scholar.google.com/scholar?q=device+free+wireless+se...

What's the economic value of remote collection of human behavioral signatures without consent, integrated with AI and robotics and "digital twins"? We're not there yet, but if the technology continues improving, what's the future value of "motion capture" of humans without body-worn sensors?

In theory, this will enable "Minority Report" user interfaces. 3D gestures could be combined with "AI" voice interfaces. Biometric authentication (e.g. heart rate) could replace passwords. Walk into a room and it adapts itself to your preferences. Etc.

There are lots of "cool" Jetsons sci-fi use cases, but ONLY IF the data and automation are entirely under control of the human subjects, e.g. self-hosted home server, local GPUs, local LLM, local voice recognition, etc.

heywoods 6/30/2025||

[flagged]

anitil 7/1/2025|||

If you had a particular idea from the LLM that you wanted to share people would be more receptive, but just dumping the whole output comes across as intellectually lazy

tomhow 7/1/2025|||

Please don't do this. Whether it's LLM-generated or not, we don't want big blocks of text from elsewhere pasted into comments here. Please at least try to craft original human thoughts.

smallerize 6/30/2025||

This is actually a feature of the Plume wifi mesh devices. https://support.plume.com/s/article/Sense-Live-View?language... It's also available from any other ISP that uses them, or if you buy your own Plume device and a subscription. It's been there for years. https://arstechnica.com/gadgets/2020/03/from-wi-fi-to-spy-fi...

transpute 6/30/2025|

https://staceyoniot.com/the-next-big-wi-fi-standard-is-for-s...

> The IEEE plans to take the concepts for Wi-Fi sensing from the proprietary system built by Cognitive (which has been licensed to Qualcomm and also Plume) and create a standard interface for how the chips calculate interference that determines where in space an object is.

Other firmware sensing capability: https://www.cognitivesystems.com/caregiver/

  - Activity Tracking: Detects movement patterns to identify changes in daily routines to spot health concerns 
  - Sleep Monitoring: Tracks sleep duration, wake times and nighttime interruptions to assess sleep quality
  - Anomaly Detection: Establishes household baseline to proactively identify unusual patterns & changes in activity

amazingman 6/30/2025||

Put your cable modem in bridge mode and use your own WiFi.

I used to recommend using your own cable modem as well, but these days you have to use the Xfinity modem to avoid overages if you're in a market with data caps.

Comcast has a stellar network operations unit, but their business operations are creepy and exploitative.

Banditoz 7/1/2025|

Is their network good, though? They try to keep my data in their network as long as possible affecting latency to certain places, which is significantly worse than what fiber providers in my area do.

erikerikson 7/1/2025||

About fivish years ago I interviewed with a Wi-Fi device maker and the engineer I interviewed with was bragging that they could watch users walk around their home.

snickerbockers 6/30/2025||

Okay I'm as concerned about privasy as everybody else is here but i also gotta admire that its pretty neat they can actually do that. Are they measuring the signal echo like what radar does? If they controlled both the receiver and transmitter i wouldn't be as surprised to find out they can tell when something crosses between them and form a 2-dimensional mesh (like that episode of Star Trek TNG where geordie detects cloaked romulan ships by having starfleet deploy a fleet of ships that send signals back and forth and look for timing variances) but if I'm understanding correctly this is different because they only control a single point in the network?

I wonder if they have enough information to make out shapes or if it's just a simple rangefinder?

thfuran 6/30/2025|

It's far from great for imaging, but it can be done. https://www.zmescience.com/research/inventions/wifi-technolo...

transpute 7/1/2025|||

Similarly, "DensePose from WiFi" (2023), 40 comments, https://news.ycombinator.com/item?id=34423395

snickerbockers 7/2/2025|||

Honestly even that is pretty incredible. At the very least that's enough date to count family members, possibly ID them if they have different-shaped bodies, and identify certain activities with obvious silhouettes (eg, sex).

I don't think it justifies the impending orwellian hellscape this technology will eventually unleash, but one positive thing about this that has me a bit excited is that this could easily clear up many ambiguities in criminal cases. for example, fairly often a death will get ruled as a suicide but victim's relatives and friends will insist that it must have been a murder; imagine being able to use this technology to definitively prove whether or not there was another party present when the victim died.

Or in rape cases where the defendant is protesting their innocence, knowing the body language of the victim and the defendant could be a vital clue because you might be able to observe the victim fighting back.

Again, I don't think the positives outweigh the negatives to the point that it could ever justify an invasion of privacy on this scale (you might as well just make everybody let the government set up a thermal camera in their house!) but it is interesting to think about the problems this could solve.

jml7c5 6/30/2025||

The term for this sort of thing is "WiFi sensing". Relevant HN thread from 2021 ("The next big Wi-Fi standard is for sensing, not communication (2021)"): https://news.ycombinator.com/item?id=29901587

As far as I can tell, devices were already on the market when that thread was made. 802.11bf was standardization to help along interoperability and future products.

Dowwie 7/1/2025||

I worked in a nascent water tech space recently involving an IOT water flow sensing device installed on a main water line. I worked extensively on detection models capable of distinguishing water fixture use during simultaneous usage scenarios. When your full time job involves a niche domain such as this, a whole new world begins to reveal itself. You can distinguish people based on their patterns of fixture usage. You can determine how many people are living in a residence. You can determine hygiene habits of each person. There's a lot more to these smart home devices than what meets the eye. You thought the sensor was good for just detecting leaks and approximately breaking down water consumption? Think again.

This device alone is capable of doing a lot, but when combined with other sensing devices such as a WIFI motion detection system, you can create a system where the whole is greater than the sum of the parts. First, you may not even need to monitor water flow now because detecting a person in the bathroom, moving about, is sufficient to detect toilet usage followed by hand-wash, and shower usage. You will know duration of each. You may be able to distinguish people in a residence, which means you'll learn who did what throughout a household.

Right about now you may be wondering who would ever want to know this kind of stuff? Who cares if you just used the toilet and didn't wash your hands? Who cares if you frequently use the toilet, or wash your hands excessively, or frequently and excessively wash your hands throughout the day? What if you are a landlord with a tenant leasing agreement stipulating no one other than the listed members on the contract shall occupy the residence without permission of the landlord (with exceptions, of course).

tedd4u 7/1/2025|

Thanks for sharing this. Check out this other comment on this page to see what one company says they can do (health baselining etc)

https://news.ycombinator.com/item?id=44428654

chimeracoder 6/30/2025||

One takeaway from this is that there's a strong privacy case for disabling the built-in wireless network from your ISP-provided modem/router and using your own, to reduce the number of ways that your ISP can surveil you.

o11c 6/30/2025||

My home ISP's cell router (because no other internet reaches our area anymore) has almost no configurable settings (just wifi name/password/hidden), and actively forbids you from disabling wifi even though I only use it through the wired connection.

(And what limited configurability it provides is only through the app, which requires you to agree to their "molest your privacy policy". I had been content with just not installing the app , but my threat model hadn't considered this new development ...)

chatmasta 6/30/2025|||

That’s always a good idea, but they’ll still be able to tell when someone is home because the outbound internet traffic will increase.

And don’t forget to set your DNS to a non-ISP resolver.

sneak 6/30/2025|||

SNI is not encrypted.

You need a box downstream of your ISP devices that encrypts all traffic out over a VPN. This is what I do.

calvinmorrison 6/30/2025||||

So you need fake upstream downstream traffic, put your router in a lead box, use DNS over https, and then all that for nothing because the Amazon router was backdoored by the NSA too

chimeracoder 6/30/2025|||

> That’s always a good idea, but they’ll still be able to tell when someone is home because the outbound internet traffic will increase.

Sure, but not necessarily who is home, since they won't have the MAC address of your device(s) connecting.

Also, traffic volumes are a lot noisier of signals than you might think, given how much automated and background stuff we have these days.

ghurtado 6/30/2025|||

Even better, don't use the Comcast router at all. It's a rip off anyway

jayd16 6/30/2025||

Don't they hand out combination modem/routers? What's a cheaper alternative?

reanimus 6/30/2025|||

Buy your own DOCSIS modem, opt out of renting theirs. It'll pay for itself after a few billing cycles (the modem rental fee is $15 per month)

ac29 6/30/2025|||

I did this recently and found out Comcast considers some security feature that runs only on their hardware to be part of the bundle they sold us.

So, bringing your own modem gets rid of the rental fee, but requires moving to a different plan without the security feature bundled. This is of course more expensive, almost entirely negating the savings of bringing your own network equipment (I think our net savings is $5/month, which means its going to be a couple years to pay back the modem cost).

gia_ferrari 6/30/2025||||

If you're on a cheaper lower speed subscription, you can often find compatible modems at thrift stores for a couple dollars. People upgrade to faster tiers and unload their old perfectly serviceable equipment good for a couple hundred megabits - fine for most needs.

jayd16 6/30/2025|||

Wow, what a deal. Last I looked it was $5/mo. Spectrum doesn't give you any discount at all.

Still I thought a good DOCSIS 3.1 modem would be a few hundred.

slt2021 6/30/2025|||

I bought a DOCSIS modem+wifi AP on amazon a decade ago for $50. Its been working like a champ and I have control over it.

although for the best control it is recommended to buy modem separately and wifi AP separately, because Comcast can send C&C commands to your modem over the copper cable

tripdout 6/30/2025|||

If it lets you. I think Bell modem+router+AP devices always broadcast a TV network with no way of disabling it whether you have TV service or not.

anonymousab 6/30/2025||

That's what a good-ol' Faraday cage is for.

gia_ferrari 6/30/2025||

Or unplugging the internal antennas. Only on equipment you own, of course.

jeffbee 6/30/2025||

This is piled on top of the existing strong case for all Comcast wifi equipment being hot garbage. If some confluence of poor regulations has led you to being stuck with Comcast, the least you can do for yourself is get your own DOCSIS modem and routers and access points that you control.

1970-01-01 7/1/2025||

Score one more point for the tinfoil hat crowd:

1. Black tape over our webcams to keep them from watching us.

2. Cardboard over our windows to keep laser microphones from hearing us.

3. RFID blocking wallets to keep our money safe from them.

4. WiFi motion detectors watching our every move in our own home. <---You are here.--->

5. Aluminum underwear keeping our private parts from being scanned into AI at airports.

6. Tinfoil hats protecting our thoughts.

class3shock 7/1/2025|

Next step it will just be a feature they offer and whether you know of it, use it, or want it, it'll always be on in the background due to you signing a terms of service that lets them. And then it'll not just be in a xfinity router but your tv, phone, etc. Just makes me want to live in a cabin in the woods.

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