WiFi signals can measure heart rate
179 comments
·September 4, 2025supernova87a
bcrl
In telecommunications construction we are taught to make ample use of the "hammer test" when working on and around poles. The difference in sound between a good pole, a marginal pole and a completely rotten pole is quite significant.
jacquesm
You could of course just bury your lines.
bcrl
Too expensive where I live. Rocks, hills and trees: the natural enemies of buried fibre and wireless networks. One of my competitors took 6 months to bury a cable in granite that would've been a 5 day aerial job.
karlgkk
Did you invent that thought from first principles without running face first into the brick wall of reality?
NoPicklez
And I wonder why that hasn't been commonplace if its just that easy
bri3d
Source article (2001!): https://electricenergyonline.com/energy/magazine/4/article/n...
I can’t tell if this ever became a reality; I know of more modern approaches attempting to use thermal and multi spectral imaging to achieve the same goal.
nashashmi
What kind of helicopter of what size are we talking about here that can actually get close to a utility pole with wires going across?
gerdesj
I live near a helicopter factory and when the spinning towers are in use, you hear all sorts of auditory patterns as you move around the town. When they are test flying - similar and the Police have one and there is an air ambulance too. My Dad's other staff car in the '80s was a Gazelle and in the '70s he whizzed around in a Sioux. I've seen and heard a lot of helos!
I have absolutely no doubt that with some funky signal processing you can do all sorts of things.
morkalork
And here I thought living behind a few garages that rev engines all day long was disturbing
privatelypublic
HV transmission line inspection routinely has the linesmen crawl out of helicopters onto the lines and back. Granted, as far as I know its the highest skill and most difficult helicopter job.
jacquesm
I've seen that in person while in Canada and it is most impressive. The moment they discharge the differential between the helicopter and the line is just awesome. The firebreak clearing operations are also something to behold. From a very safe distance.
trenchpilgrim
Look up "Helicopter tree trimming" and prepare to be amazed.
fsckboy
also look up "helicopter high voltage wire"
trhway
I think you can do it from a distance, just need to have directed microphone (or use laser “microphone”)
shitpostbot
That makes sense. It's probably less "doing crazy convolution calculations on how sampled ambient noise changes as the helicopter gets close to a pole", and more "rotten wood vibrates slower"
aaron695
[dead]
kqr
People are suggesting this to continuously monitor vitals. Others think that is a privacy problem. There might be an even bigger problem: continuous vitals monitoring might lead to over-medication and perhaps be worse for patients.
One of the reasons vitals are such a good diagnostic tool is that we monitor them specifically when we already suspect something might be wrong. Monitoring healthy patients reveals the large variation in vitals -- some that might even appear problematic.
We know this among other things because we have accidentally experimented on babies and mothers during delivery. Some clinics have a policy to put them on continuous monitoring the moment they arrive and they get treated for more things with worse outcomes when they're otherwise healthy. Maybe this is confounded (some clinics overmedicalise everything -- both monitoring and treatment) but I like the intuitive explanation that excess monitoring causes excess treatment.
freedomben
Can't help but think of the Star Trek TOS episode where Kirk is accused of murder and they find the "murder victim" in the ship by identifying and isolating heart beats until they discover he must still be aboard. It's been almost 60 years since the episode came out, but still sorry if that's a spoiler
wrs
Classic Star Trek (speaking as a fan). They can scan an entire planet to find a lost crew member, but can’t tell how many people are on their own ship. And they have universal audio surveillance on the ship but still have to use wall intercoms.
Cthulhu_
The Star Trek series require a lot of suspension of disbelief, especially since in the years after it came out real life technology surpassed the stuff depicted in there. Like, in TNG people walking around with glorified e-readers but having to go to the big computer or to ask Alexa things instead of just tapping on their screens.
At least they got OLED style touch screens, and for a while it looked like everything would go that way but at least in cars some are going back to physical buttons.
eurleif
One thing that I feel actually became more believable with new technology is the plot device where only one character can perform a certain task, but then all they really do is tell the computer to do it. For example, in Voyager, they make a big deal about how Harry Kim is the only one who's able to make complex holograms. That originally seemed unrealistic; but now, with the amount of work some people put into prompt engineering for LLMs, it actually seems kind of plausible.
lovemenot
In the new TV series Alien Earth, the low resolution CRT monitors and clunky keyboards aboard interstellar spacecraft really stand out. Presumably it's an homage to the 80s' movies.
lo_zamoyski
> At least they got OLED style touch screens, and for a while it looked like everything would go that way but at least in cars some are going back to physical buttons.
On that note, physical buttons are tactile and easier to navigate while driving and thus safer. You don't have to take your eyes off the road and worry about a fussy touchscreen registering your tap. You just feel around for the control and manipulate it.
The appeal of a touchscreen is that you can change the interface. It can assume a wide range of control panels, which, in a car, isn't always useful. For functions you need immediately, you can't beat a fixed physical widget.
Now, what would be interesting is a surface whose physical texture and physical controls could be dynamically changed and reconfigured. So, a flat surface becomes a series of buttons, and then maybe a rotating knob in the next. Perhaps tactile holograms. I don't think something like this could beat physical controls for reliable and lasting function either, however.
ck2
I mean, they have GRAVITY PLATING
We could many centuries from now have "warp drive" but GRAVITY PLATING is completely implausible
Yet it makes every episode of each ST series watchable so we just accept "the future"
varenc
There's a single DS9 episode[0] where they reveal that the Captain can actually spy on everyone on the ship at once. Like tap into a video feed and listen to conversations. But then we never see this happen again.
My headcannon for this is that even though it's technically possible, it's so unethical they just choose to never do it.
[0] https://memory-alpha.fandom.com/wiki/Valiant_(episode)#:~:te...
cout
I don't remember that episode. But it does not surprise me that the Cardassians would build that feature into their station.
protocolture
>My headcannon for this is that even though it's technically possible, it's so unethical they just choose to never do it.
IF theres something unethical that they choose not to do, you can be sure Sisko is doing it.
mistyvales
Odo spies on Quark in Season 2. Think it was the Maquis two-parter? He doesn't care about Federation ethics early on though.
matheusmoreira
"Humans are ethical and behave morally" is a core idea behind every Star Trek episode featuring the Enterprise. Its relentless optimism is almost innocent in nature...
DS9 is great because it showed us the darker side of the federation. They can afford to be like this because they've got Space CIA committing atrocities behind the scenes since day one.
vkou
The mirror universe captain of the Enterprise-C uses that exact functionality, in conjunction with a disintegration beam to quietly disappear problem crew members.
deepsun
My phone can hear me and answer whenever I talk to it, but I still prefer to push a button first (kinda intercom), or even just type :)
null
vkou
Oh, it gets worse. Either Kirk or Spock should have hung for that episode - not for the thing Kirk was on trial for, but for leaving the entire ship unmanned, and for allowing that guy to terminally sabotage it, all to do some theatrics for the judge and jury. That is a criminal level of negligence - surely it was in violation of some minimal crewing requirement for a vessel of that size.
I also have to wonder what the 'dead' guy's plan was after Kirk would get convicted for his death. Presumably he'd need to climb out of whatever rathole he was hiding in for breakfast, and I'd presume someone on the ship would notice that the dead guy is alive, and that the conviction should be overturned.
---
Truly, the level of and attention to security on the Enterprise-C was shameful. In "The Conscience of a King" (an excellent episode), one of the traveling actors manages to - not only steal a weapon - presumably from the armory - but also rig it to explode and plant it in the Captain's quarters.
Starfleet in that era should have seriously formed an independent, no-bullshit, no-nonsense commission to ask the relevant enlisted and commissioned officers pressing questions, like 'Did you, or did you not leave the hatch coaming on Deck C open, thus allowing an enemy agent access to the arms locker? Are you in collusion with enemy agents?'
mrexroad
Maybe it’s just a Boomer thing? (Sorry, couldn’t resist the BSG / trek crossover joke).
MarcelOlsz
You took away my ability to make a cheesy "spoilers!" comment, which is arguably worse than having spoiled the episode (thanks, btw).
thrance
Humorous summary: https://www.mezzacotta.net/planetofhats/episodes/0020.html
TowerTall
Everyone’s heart is different. Like the iris or fingerprint, our unique cardiac signature can be used as a way to tell us apart. It can already be done from a distance using lasers [1].
[1] https://www.technologyreview.com/2019/06/27/238884/the-penta...
transpute
https://www.theregister.com/2025/07/22/whofi_wifi_identifier... | https://news.ycombinator.com/item?id=44685869
> Researchers.. developed.. a biometric identifier for people based on the way the human body interferes with Wi-Fi signal propagation.. CSI in the context of Wi-Fi devices refers to information about the amplitude and phase of electromagnetic transmissions.. interact with the human body in a way that results in person-specific distortions.. processed by a deep neural network, the result is a unique data signature.. [for] signal-based Re-ID systems
knowitnone2
fingerprints don't change, heartbeats do. Every heartbeat is different so it'd be difficult to even tell which heartbeat is yours for any giving signature.
onlypassingthru
No clunky wearables? No chest strap on the treadmill? Heart rate and respiration? Monitors everyone in the house simultaneously 24/7 on a cheap rpi? I hope this doesn't take years to come to market because this seems incredibly useful.
transpute
There are positive 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, offline voice recognition, private 3D imaging of home and human, etc.
bluGill
I don't want the data under my control - I want it under my doctors control. Except if it decects a coming heart attack or such, then notify every emt.
transpute
If you have control of your data, then you can delegate to doctors, EMT or other agents.
fragmede
Comcast renting out wifi hardware to all of their customers, and already bringing that technology to the masses should be concerning to you then.
transpute
Sensing is (sadly) already 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, keystrokes, hand gestures). It can also be done with $20 ESP32 devices + OSS firmware. The open questions are on custody and legal usage of CSI measurements, not their existence.
wlesieutre
But think of how much money they can make by selling your health data to insurance companies!
throwway120385
Yet another tool for our surveillance capitalism overlords to figure out when people are having sex.
captainkrtek
Could also see the value of this for caregiving. I caretake for my grandmother, and even something as simple as keeping airtags on her keys has been a challenge. It would be impossible for her to consistently wear some wearable health device / life alert / etc. passive health monitoring that’s not intrusive would be amazing.
onlypassingthru
Not an expert, but I suspect for many there are warning signs that someone may die in their sleep (or exercising, or ???) long before the heart finally quits. This seems like a great way to monitor for that.
boznz
when I'm old and going to die, "in my sleep" would be top of the list of ways I would want to go, (during sex is likely not going to be an option)
captainkrtek
I’m an EMT, so not the deepest level of knowledge, but certain progressive things that will kill you (such as sepsis) would show noticeable trending in basic vitals like heart rate and respiratory rate. And sepsis is also common in geriatrics (catheter / surgery / G tube -> infection -> sepsis)
snet0
I've not followed any evolutions in this area, but there's a cool paper from 2014 about using WiFi channel state information to detect 87%(!) of falls in an experimental condition[1]. It's been a while since I read the paper, and I no longer have access, so caveats aplenty, but it's one of those things that pops into my head sometimes and I wonder if it's seen any real-world deployment.
makestuff
Seems like it would be really useful in a hospital setting as well. Instead of having to wear the heart rate monitors, etc. during recovery or a stress test it could be wireless.
FridayoLeary
I feel this technology would creep people out so much that anyone in the wifi space would be actively hostile towards these things. Maybe they'll lock it behind patents? I doubt governments would want this to become common knowledge either.
transpute
It has been IEEE standardized and shipping commercially for several years.
westurner
WiFi RSSI hacks (WiSee (2013),)
Linksys Aware (-2024): https://www.google.com/search?q=Linksys+Aware
From this thread https://news.ycombinator.com/item?id=45129817 :
> 802.11bf
802.11bf: https://www.google.com/search?q=802.11bf
"Whole-home gesture recognition using wireless signals" (2013) https://dl.acm.org/doi/abs/10.1145/2500423.2500436 .. https://scholar.google.com/scholar?cites=1386163076039493879...
From https://news.ycombinator.com/item?id=38246722 re: a stylus with accelerometer with many degrees of freedom and inertial measurement:
> /? wireless gesture recognition RSSI:
> /? wireless gesture recognition RSSI site:github.com
> Awesome-WiFi-CSI-Sensing: https://github.com/Marsrocky/Awesome-WiFi-CSI-Sensing
> 3D Scanning > Technology, Applications [...]
GordonS
Whole-home gesture recognition sounds really cool! Has anyone actually got this running?
pizzly
Seeing that it works for a ESP32 chip I would say that its very likely to work on a smartphones's wifi chip though the article didn't say. Many people carry phones with them everywhere and all the time. You could build a very impressive profile of a person. It could be used to see when they get excited, scared, angry, etc at depending on what they view on the phone, the phone call they received, where they physically located on the earth, who they are around (by looking at identities of other phones near them) and properly other things as well I have not thought of.
PranayKo
Hey guys I am the high schooler who developed this let me know if you got any questions I'd be happy to answer them
notpushkin
Congrats, very impressive!
The linked article is a bit light on actual details – could you share the paper/preprint maybe?
PranayKo
Thanks!
https://ieeexplore.ieee.org/abstract/document/11096342
That’s the official paper link. Sorry it’s not open access.
notpushkin
Too bad :( Though I’ve just found a PDF here in the open: https://news.ucsc.edu/wp-content/uploads/2025/08/Pulse_Fi_sh...
er0k
This is nothing new. Wifi signals have been used to detect objects, people and animals, gait analysis[1], read keystrokes[2], monitor breathing and heart rates[3], "hear" conversations[4], etc for at least a decade now.
https://news.ycombinator.com/item?id=12353605
https://www.theatlantic.com/technology/archive/2016/08/wi-fi...
1: https://ieeexplore.ieee.org/document/7457075
Uehreka
Have you gotten any of these to work? A few years ago I was tasked with investigating these kinds of techniques for a client (it was something cool and benign but I can’t say what due to NDA) and the big papers people are referring to when they mention this all had either huge asterisks or huge methodological flaws.
IshKebab
In my experience aallll of these fancy "we can measure things that sound impossible" papers come with the asterisk "in perfect lab conditions".
> “The signal is very sensitive to the environment, so we have to select the right filters to remove all the unnecessary noise,” Bhatia said.
AKA "it barely works and we had to filter the signal to the gills to get anything at all".
It's a really impressive tech demo but the article is selling it as if this might actually work in the real world and it clearly won't.
ACCount37
Getting it to sort-of-work is fairly easy. Getting it to work well on off-the-shelf hardware without a precisely controlled environment is hell.
For practical applications right now, you'd want a dedicated radar unit at 24GHz or so, probably with two separate reception paths too.
Eventually, we might get usable radar functionality in default Wi-Fi chips with 5GHz/6GHz Wi-Fi and MIMO - but it's not there yet.
genewitch
i get asked about stuff like this from time to time and i always say "no, that's impossible" because i have ethics. The common retort is "well, i heard it was being used at <x>." and a client never contacting me again, which is fine.
antoniuschan99
Try using this you just need an esp32 devkit nodemcu style pcb. It measures movement though.
LPisGood
Indeed, this same principle has been shown to work with sound waves and not just RF waves. There was a paper a few years back that used car speakers and the microphone to be able to detect the number of people in the car for the purpose of detecting children or pets left in hot vehicles.
umvi
Generally I think this is called "tomography" (https://en.m.wikipedia.org/wiki/Tomographic_reconstruction) i.e. the reconstruction of higher dimensional data from lower dimensional data. Your brain can do it automatically in a lot of cases. For example if you see the shadow of a rotating cube on the wall, your brain can reconstruct 3d information about the cube even though you only have access to a 2d projection
throw0101d
802.11bf is working on sensing applications:
> With recent advancements, the wireless local area network (WLAN) or wireless fidelity (Wi-Fi) technology has been successfully utilized to realize sensing functionalities such as detection, localization, and recognition. However, the WLANs standards are developed mainly for the purpose of communication, and thus may not be able to meet the stringent requirements for emerging sensing applications. To resolve this issue, a new Task Group (TG), namely IEEE 802.11bf, has been established by the IEEE 802.11 working group, with the objective of creating a new amendment to the WLAN standard to meet advanced sensing requirements while minimizing the effect on communications. […]
* https://ieeexplore.ieee.org/document/10547188
> In recent years, Wi-Fi has been shown to be a viable technology to enable a wide range of sensing applications, and Wi-Fi sensing has become an active area of research and development. Due to the significant and growing interest in Wi-Fi sensing, Task Group IEEE 802.11bf was formed to develop an amendment to the IEEE 802.11 standard that will enhance its ability to support Wi-Fi sensing and applications such as user presence detection, environment monitoring in smart buildings, and remote wellness monitoring. In this paper, we identify and describe the main definitions and features of the IEEE 802.11bf amendment as defined in its first draft. Our focus is on the Wireless Local Area Network (WLAN) sensing procedure, which supports bistatic and multistatic Wi-Fi sensing in license-exempt frequency bands below 7 GHz (specifically, 2.4, 5, and 6 GHz). We also present an overview of basic sensing principles, and provide a detailed discussion of features defined in the IEEE 802.11bf amendment that enhance client-based Wi-Fi sensing.
* https://www.nist.gov/publications/ieee-80211bf-enabling-wide...
* https://www.cognitivesystems.com/how-does-802-11bf-enhance-l...
(See also perhaps IEEE 802.11bi, Enhanced Data Privacy.)
01HNNWZ0MV43FF
802.11 Blue Falcon
elric
It's galling that this press blurb only focuses on happy (supposed) health monitoring benefits, and fails to address the privacy concerns in the slightest.
This can be abused in so many ways, like watching how people's heart rates change then watching an add, or browsing a selection of goods in the shop, and making viscerally targeted advertising. Or burglars detecting whether people are at home.
Soon we won't just have to worry about unpatched wifi routers being parts of botnes, we'll have to worry about them tracking our locations and excitement levels and selling them off to whoever.
zekrioca
There are products already that do this: https://www.originwirelessai.com/
proee
This would be great for measuring heart rate while asleep because I can stand wearing a watch in bed, and my watch is charging at night as well.
Hey, I heard about how utility pole inspecting helicopters are able to tell the good/rotten state of wooden telephone poles by the reverb pattern of sound waves coming off the poles from the rotors -- it seems to me the whole field of non-invasive sensing (and using existing/ambient emission sources) is getting pretty impressive.