Wi-fi signal tracks heartbeat without wearables
spectrum.ieee.org103 points by JeanKage 7 days ago
103 points by JeanKage 7 days ago
I wish Wifi would be restricted for network use and not (invisible, non-consensual) surveillance or monitoring of any kind. Maybe it's time to start contacting regulators, who probably have no idea about this
Unfortunately it's kind of hard to truly restrict its usage. The data transmission and sensing capabilities of WiFi are two sides of the same coin: flashing morse code via a light into a room also makes it possible for anyone with eyes to see what's in the room. WiFi uses non-visible radiation but the same principle applies. What's more, higher transmission rates are made possible by higher frequencies of radiation which have physically more capacity for information density, whether information encoded into the radiation by a special device or encoded into it from from interaction with the environment.
If you want more information about this whole thing as an engineering project, check this comment from a few years back with lots of links: https://news.ycombinator.com/item?id=22480444
I guess what the mean is the same way spark gap transmitters are forbidden. Anyone can do it but it's forbidden. Anyone can read the wifi signals but CISCO doesn't have to sell you a dashboard with real time view of your location and everyone walking through it with all the websites they visited since they walked in, last time they were at your location, average time they are there, to communicate to a store in the mall that you're almost in front of it so it sends you a push notification with an ad, etc.
> Unfortunately it's kind of hard to truly restrict its usage.
Is it? You require any wireless device to have open source firmware and then people can a) inspect what the existing firmware is doing and b) replace it if it's doing anything they don't want it to.
It's a matter of replacing the existing obscurity-focused laws discouraging them from doing this with the security-focused ones that require them to.
The benefits in terms of right-to-repair and ability to patch vulnerabilities in devices the OEM has abandoned redound on top of this.
Totally, I agree that wireless devices doing sensing applications ought to be transparent about that.
That said, wireless devices are basically "light bulbs" in whatever spectrum they operate in. It's very hard to restrict people from driving by with a "camera". I believe these kinds of applications are called "passive" in the literature, and 5G is especially designed with this in mind. WiFi has been known to be good for this for a while.
In order to facilitate more privacy preserving communications that are less sensing friendly we would need highly directed packets using stuff like microwave lasers etc., so as to reduce the ambient radiation.
So there are two issues here. One is, you buy a Wi-Fi device at the store and it spies on you and sends all the data to somebody else's cloud. That one's quite solvable with open source firmware. The other is, they're not using your device, they're using their own.
Restricting someone from having a device that can do that is basically a lost cause. Anyone could make one using a variety of existing commodity equipment or use SDR with multiple antennas. It doesn't matter what some future Wi-Fi device does in that respect because if it's their device they can do whatever they want. If that's your threat model you either need a law that bans them from doing that or a Faraday cage around your building.
It is kind of hard to truly restrict its usage sure but how about we don't create IEEE standards for it.
You would get uncomfortable seeing an IEEE 802.11dp that's able determine if you're wearing an underwear that day, but they are going in that direction.
IEEE 802.11bf is the one you're looking for as far as WiFi goes. 5G and 6G are bigger than 802 but have been quite "transparently" designed with sensing in mind, as in you can read 100s of industry publications about this.
IEEE has a whole working group for standards around this stuff: https://signalprocessingsociety.org/community-involvement/in...
Here's a paper about related standards: https://ieeexplore.ieee.org/document/11142711
The paradigm itself goes back decades now. It used to be called "joint communication and sensing" in the 00s, and then it was called "integrated sensing and communications".
I would rather a standard exist so that the layperson can get a sense of what’s possible.
Grounded radiant barrier (matte white vinyl with aluminum on reverse side) in 48" rolls will block wifi and temperature for $0.25 per sq ft.
2023, https://www.policemag.com/technology/article/15541542/first-...
> “Once you place it against the wall, it takes one scan to show you where everything is, then over time anything that moves will pop up.. It can detect someone moving through the room or someone sitting on the couch and breathing. The small movements of breathing are enough for the radar to discriminate between the couch and the person.”
2015, https://www.usatoday.com/story/news/2015/01/19/police-radar-...'
> At least 50 U.S. law enforcement agencies have secretly equipped their officers with radar devices that allow them to effectively peer through the walls of houses to see whether anyone is inside.. The radars were first designed for use in Iraq and Afghanistan. They represent the latest example of battlefield technology finding its way home to civilian policing and bringing complex legal questions with it.
The police in Netherlands also operates these from inside vans. Most likely other countries too. They do this most busy weekends in the Dam Square for example. You walk by you get a full body scan to see if you have weapons on you I guess. I hope they like my butt.
Would be a shame if they'd arrest someone for carrying a toy gun or a gun-shaped ball of aluminium foil.
It's built into the WiFi 7 standard.
A lot of spaces you assumed were private are no longer so.
Nick Bild replicated the paper and shared their build on hackaday.io.
https://hackaday.io/project/204077-measuring-heart-rate-usin...
Kinda crazy the arc that 60GHz has taken over the years.
Like ages ago it was going to be Intels docking station standard (WiGig). It died, companies like IgniteNet bought up all the Dell wigig chips, and used them to prototype P2P wireless radios, ultimately building out a new class of metro p2p wireless used by every major vendor. Then it became a component of 5G, mostly used for backhaul but still capable in a lot of Massive MIMO handsets. Some handsets trialling it for in home wifi. And now the chips are probably going back into your laptops/Homes to detect your biometrics.
> your laptops/Homes to detect your biometrics
Intel laptop demo (shipping since 2023), https://news.ycombinator.com/item?id=45127983#45130061
Not even 60GHz. We're talking 2.4/5 here
Oh thats cool. I just saw a reference to ESP32 and I know they do a 60GHz heart rate unit. Some HA guys have been using it
The 60GHz heart rate sensor you're talking about (this one maybe https://wiki.seeedstudio.com/ha_with_mr60bha2) can be used with any microcontroller. It's got nothing to do specifically with ESP32, which is just one kind of microcontroller you can use it with.
260 comments | 1 month ago
Thanks! Macroexpanded:
WiFi signals can measure heart rate - https://news.ycombinator.com/item?id=45127983 - Sept 2025 (262 comments)
I believe this was posted to HN about a month ago and had a good discussion https://news.ycombinator.com/item?id=45127983
Let me guess, it use some kind of ESP32?
opens article
> First, the researchers had seven volunteers sit in a chair at various distances of 1, 2, and 3 meters from two ESP32 microcontrollers that used Pulse-Fi to estimate the volunteers’ heart rates
Yup
Oh yes, I've been actually looking at integrating this and other mmwave research into my startup https://trackourhearts.com
Non-intrusive technology which can work at home to monitor people' vitals is a game changer, there are so many applications to this. Research is at the beginning.
Indeed there are privacy issues with big providers doing this, but then this really opens up so many possibilities if done well.
Indeed there are privacy issues with big providers doing this
And if they offer you enough money to acquire the company, you'll take it, because if not you then someone else will do it. Humanity is not in fact crying out for a better panopticon.
[flagged]
We've banned this account for repeatedly breaking the site guidelines badly. Not sure what's going on here, but you've been posting like this a lot, and that's not ok.
If you don't want to be banned, you're welcome to email hn@ycombinator.com and give us reason to believe that you'll follow the rules in the future. They're here: https://news.ycombinator.com/newsguidelines.html.
If I could take my watch off while I sleep and still get good heart rate / sleep tracking from devices positioned around my bed that would be great. My watch can cause skin irritation and I find it valuable but not having it on while I sleep would probably be healthier. Also as I get older if I could put a wifi device in each room that did active tracking and not have to carry a device I need to keep charged that would be great for life alert style thing, and general health monitoring.
You're making a lot of loud baseless claims really quick, aren't you?
Radar technology isn't some kind of forbidden magic. Can you do radar sensing with 2.4GHz? Yes, absolutely. Now, can you do it well, with an off-the-shelf Wi-Fi chipset, and get down to heartbeat monitoring? Only if the chipset was designed for it. Very few existing chipsets are. Still a new experimental thing.
For practical applications today, I would look instead at things like dedicated mmWave 24GHz radar chips instead - they're getting cheap now. For the future? If chip vendors that ship the usual 2.4GHz/5GHz MIMO router chipsets start putting the relevant features in, the idea would be worth visiting.
If I had the ability to track users heart rates in response to advertisements, media, political content, etc that would be quite valuable for producing content that better captured users and made them feel what I wanted them to feel. Heart rate says a lot about what we're feeling and our attention, especially if you have it all the time and can match it to what we're looking at.
Well that’s good for you but only occasionally good for the users. Often it’s the opposite, sorta gets used against them.
I mean, obviously. That's not the question though, the question is utility. There is undoubtedly utility, it's just that you are the product, not the beneficiary.
Oh okay I get your point. Yeah we’re fucked because it is pretty useful.
What's scary is that Comcast will be using this to spy on people, and that's going to get back to the government and the cops and the new gestapo will also have that. Not to get all conspiracy theory on y'all.
They already are. Their app advertises an option to determine how many people are in your home via Comcast WiFi right now, not using connections to devices, but radar. I don't think Comcast will stop at just that.
It’s absurd to think they’d do such a thing.
Checking if your phone is attached to their router is much less signal processing!
Haha fair. The current technology is fairly limited and doesn't work through walls, but if we handwave that it will in the future, and if you're living in a an apartment complex and the neighbors have Comcast and you don't, it seems like a bit of more of a problem.
"Xfinity using WiFi signals in your house to detect motion", 500 comments, https://news.ycombinator.com/item?id=44426726#44427986
Anybody remember the heartbeat scanner in Tom Clancy’s Rainbow Six?
Yep. But my first thought on usage was "man this will make detecting home occupancy simpler" (till it turns out you can't distinguish from pets I suppose).
Pet heart-rates probably fairly different and “quieter”.
Only if they are small pets. A Mastiff for example is going to have a heart rate extremely similar to a human.
This would be great for smart home if it can accurately detect which room you are in.
In 10 years even through walls, probably.
Elementary Watson, we simply observed the swaying motion of the fly's winds to determine the heart rate
It could be used to scan people's heart rates when they're in a high security line (military check points, airports, embassies) to detect people who are nervous.
I assume some places already use thermal cameras to detect people who are sweating profusely.
Using both together might be a decent way of flagging people who might otherwise slip through security.
Of course there would be many false positives, so it wouldn't be good enough on its own.
That is the same excuse cops regularly use to violate peoples rights and justify illegal searches and stops or claim they are impaired when they aren't. The very fact that people are being closely watched or monitored is in itself a reason for people to be nervous.
Yes, some people will be stressed and nervous for benign reasons. Criminals will also be stressed and nervous.
A good security system will use multiple signals to filter out false-positives.
Yep, that's definitely what we need more of right now, not less.
What's the objection? I don't see how having my heart rate scanned at an airport or military checkpoint in any way impinges on my freedom or happiness.
Please supply your dna and biometrics at every entry point of a public roadways. Thank you good citizen.
> Please supply your dna and biometrics at every entry point of a public roadways. Thank you good citizen.
Hysterical slipper slope nonsense.
Using RF to passively detect someone's heart rate at close range is objectively less intrusive than cameras are.
Right up until they take you aside for body crevice analysis because your heart rate was a little high, anyway
Doesn't seem like a reasonable objection to me. It takes a lot of time and man power to search people's body cavities. The incentive is to avoid searching as many people as possible.
True. To avoid searching as many of the wrong people as possible, and search all of the right people. Of course, those categories are fluid.
Today you’re among the people to avoid searching; tomorrow, well… maybe you’ll have a reason to be nervous.
> Today you’re among the people to avoid searching; tomorrow, well… maybe you’ll have a reason to be nervous.
What do you even mean here? Seems entirely incoherent.
You're missing the point: if the computer picks you out for some reason (perhaps you are ill, perhaps you are worried about losing your job or a family member's health, whatever), they won't care about the economic inefficiency or the infringement on your rights. Just because you don't intend to commit crimes doesn't mean you're immunized from bad decision-making by security systems.
Explain how it's worse than a camera or thermal camera that detects you sweating? Explain how it increases the incentive to do body cavity searches?
Are you always this rude? No.
Edit: after looking through the rest of the thread, it appears that you are. Happy Saturday I guess.
Some of the responses to me were rude and I calibrated my responses to them appropriately. You stated I was "missing the point" which is more rude than me sincerely asking you to explain your rationale.
Your claims made very little sense. In my view, this potential new technology in no way increases the power of security personnel beyond what they already posses.
Because having a high heart rate doesn't mean you've committed a crime. Are you trolling?
"Of course there would be many false positives, so it wouldn't be good enough on its own."
Going through airport security is stressful and unpleasant already with a lot of people whose heart rates are probably somewhat elevated as a result.
"Of course there would be many false positives, so it wouldn't be good enough on its own."
> The incentive is to avoid searching as many people as possible
Oh good lord. Now it's no longer even "have you read a history book on the 20th century?" anymore, it's "have you been paying attention to the world for the past 15 years?".
> Oh good lord. Now it's no longer even "have you read a history book on the 20th century?" anymore, it's "have you been paying attention to the world for the past 15 years?".
Spare me the hysterics and the insults. What exactly is your claim?
That body cavity searches have increased rapidly over the last 15 years? That it's a common occurrence? That security personnel actually has an incentive to do them more rather than less?
Give me the books you read and sources you read that support your claim. I doubt they exist. I suspect you're going off "vibes" here, but I'll gladly read them if you can cite them.
> What exactly is your claim?
I think it's plain enough. That giving the state security apparatus more tools to arbitrarily harass people at their discretion is a Bad Idea™.
> That security personnel actually has an incentive to do them more rather than less?
I have absolutely no idea where you're going with this or what makes you believe this is how the world works. Are you from the US? Certain "security personnel" have been working overtime since the start of the current presidency as I'm sure you're aware... And again: picking up a history book will lead you to realise how mistaken your quaint belief is ("incentive to work less"?).
> That giving the state security apparatus more tools to arbitrarily harass people at their discretion is a Bad Idea™.
Measuring heart rate, using a computer which can log its data, is the exact opposite of arbitrary. It's an objective measurement. You don't seem to understand the words that you're using.
Are you somehow unaware of the fact that security personnel, for example TSA at airports, are already empowered to use their own discretion in deciding that particular people seem to merit extra scrutiny?
Any TSA officer can flag any person as suspicious for almost any reason. They don't abuse this power generally because they have very little incentive to and there are checks on it.
> I have absolutely no idea where you're going with this or what makes you believe this is how the world works.
Do you think TSA officers are incentivized to do more or fewer body cavity searches? Do you think they get bonuses for doing them? It's beyond ridiculous that you can't keep your argument straight and have to reference Trump in the context of a discussion about secure environment screening technology.
> And again: picking up a history book will lead you to realise how mistaken your quaint belief is ("incentive to work less"?).
I've almost certainly read far more than you on history and law. I'm likely more experienced, well traveled, and much more concerned about actual infringement on liberties.
Which, I'd argue, is why I'm less concerned about this technology than you. I know what kinds of things actually infringe on people's liberties.
Your weak attempts to talk down to me, while at alluding to non-specific events in history, would embarrass you if you knew enough to be embarrassed.