Posted by bookofjoe 9/4/2025
There is a whole field dedicated to this, called non-destructive testing. Modal response (i.e., monitor how a structure vibrates in response to an excitation) is a basic technique that features in multiple areas such as structural health monitoring and service life estimations.
Some mechanics also do this by placing the tip of a screwdriver against a point in an engine and place their ear against the screwdriver's handle. If it's not sounding right, the engine has problems.
Even pottery. You should hear the sound of a pot after you tap it. If it's muffled then odds are it has internal cracks.
Most folks in Europe climb only sport routes, or then do some variant of proper alpinism once on wild unsecured terrain.
It is a bit more than that, but there is no objective foolproof test, no.
Downside is: a drunk guy in a truck is all you need to tear it down, not to mention natural disaster influence. And it's unsightly AF.
Yes, it's fast and cheap. That's how we got the situation that a backwater village in the midst of the "anus mundi" of Romania has XGPON for a few dozen euros a month, while you're lucky to get anything above 50M VDSL in Germany outside of large urban areas and 200M VDSL in urban areas.
But holy hell it's an eyesore to be in said village in Romania, look out the window and look at a bunch of fiber strung not even from a proper pole but from a tree. Takes the German expression "Kabelbaum" to a whole new level.
The bigger issue over the last 5 years in the area where my company operates is the number of dump trucks that leave the bed up. Given the weight of dump truck it is easy for them to pull down multiple poles when they catch the cables, although perhaps they are drunk drivers...
Google Fiber wrecked entire city streets relearning these things the dumbest way possible (then left the street repair bills to the us the taxpayers, because of course they did).
Repairing becomes a different kind of nightmare.
Local municipalities establish de-facto monopolies and drive prices up, because they offer slightly faster and stable lines.
There is a joint effort by local utility companies in Mecklenburg and they’re trying to make things better, but anecdotally are also challenging to deal with.
My now residence here in the UK is not really rural and for years Giganet/CityFibre/toob promised gigabit soonTM for years and the date got delayed and delayed and delayed.
There is a common case of excessive bureaucracy and extremely conservative population (thank you, low birth rates) which is hindering any significant development in the country.
That's what you get with arrogant and ignorant large bureaucracies, anywhere, anytime :-)
OTOH, considering how well the 'megabit-chip' went, I'm wondering wtf they'd do with fiber, at the times? For the military, agencies, ministries and some universities maybe, but for the masses? How common was the 'stinknormales telephon' in households, back then?
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.
I have absolutely no doubt that with some funky signal processing you can do all sorts of things.
Mind you I also lived near RAF, USAAF and Luftwaffe bases back in the day and several flights of Phantoms, Starfighters, Jaguars and Tornadoes and the rest can make quite a din. Phantoms were pretty huge engined beasts with minimal effort made for noise reduction. A "finger four" lighting up their after burners to gain altitude really fast is ear splitting.
Email hn@ycombinator.com, they may be willing to unban you, so other people can see your posts.
We have people working around low-flying aircraft all the time. I’m guessing the associated job risks are better.
When you take those jobs, it’s because you want to make money, not because your life is at risk, there’s information asymmetry between you and the medical provider who is indirectly rewarded for billing for scans, and the overarching medical system prioritized CT scans over MRIs while our engineering culture failed to establish something safer and cheaper.
Would you play Russian Roulette with a revolver with 500 chambers and 1 bullet? What if by doing so a hospital would receive thousands of dollars, and would go on to be paid many more thousands of dollars if you got unlucky?
The cost-benefit trade-off is there, and the powers that be are prioritizing cancer.
> ...93 million CT examinations performed ... projected to result in approximately 103 000 future cancers ... cancer risk was higher in children ... CT-associated cancers could eventually account for 5% of all new cancer diagnoses annually.
Although keep in mind that these numbers do need context. cancer != death. That ranges from cold comfort (in the case painful chemo treatment & years of fear) to a critical factor (based on how the USA diagnoses it, approximately 6% of men will have prostate cancer that does not require treatment).
Based only on these numbers above and my prior beliefs, I would say that that either
A) CT scans are a necessary evil that haven't been adequately replaced
or
B) These numbers less problematic than one might expect, due to some quirk of the data
I generally trust the USA's medical establishment on new treatment, though I've heard that they're slow to clamp down on outdated treatments.
[1] https://jamanetwork.com/journals/jamainternalmedicine/fullar... https://www.nih.gov/news-events/nih-research-matters/radiati...
Also, framed another way, 5% of cancer cases caused by CT scans would mean that 1 in 20 people in the cancer ward were placed there by a CT scan. Or alternatively, phasing out CT scans would prevent 1 in 20 cancer cases, with prevention being worth more than a cure for every 1 cancer patient in 20.
If we had gotten our heads out of the sand on pushing CT scans as the answer, years ago we might have progressed further on other tech too.
E.g., photons: https://medicalxpress.com/news/2025-06-scientists-entire-hum...
And yes, you can still see bone in an MRI. A related question is, how well can you see soft tissue in a CT scan?
CT scans are routinely used to diagnose soft tissue problems, where they are the wrong tool for the job: an MRI would be more ideal. CT scans in these situations expose the patient to avoidable cancer risks while compromising the level of insight provided to the medical provider.
Interoperative imaging is another specialist use case. The need for CT scans in specialist situations speaks to the failure to develop alternatives with lower cancer risks. Also, the need to use a CT scan in certain situations does not mean that the CT scans should be used in other situations.
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...
IF theres something unethical that they choose not to do, you can be sure Sisko is doing it.
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.
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.
(2023)
https://www.engadget.com/2015-09-23-geltouch.html
(2015)
PADD was still futuristic enough at that time but what they didn't predict behind scenes was multitasking in software. Characters in old series were seen working on multiple devices like on multi-page documents. Tho, you can always say that it was just a gimmick to show character being really busy.
Some 30 years ago there was this Australian tv show for kids created where by sheer luck a damaged satellite fixed itself and let group of random kids around the world magically have a Zoom-like meetings for education and... making art thieves lives miserable. Prop department utilized still new at that time Sharp OZ-7000 (one of first such devices, before even PDA was coined) as communication device equipped with small colored LCD and weird looking "gem" camera. Back then that was a futuristic fantasy that seem impossible. And here we are, with smartphones that can make video calls at ease by Internet for last few years.
People do that in real life all the time even with the ability to do everything on one handheld device today. People pick up preferences for using "apps" on specific devices, or have multi-tasking use cases where flowing across devices feels nice or makes the most sense.
For instance: Using an iPad to read a kitchen recipe and calling to Alexa or Siri on a nearby Echo or HomePod to set a kitchen timer while watching a show on a kitchen screen, say powered by an Apple TV. The iPad could picture-in-picture the show and track the timer and show the recipe all at the same time, but that's not the experience everyone wants. It's not even the experience that Apple wants to sell to people. If you've got an iPad and HomePod in the same room and call for Siri, the software is built to prefer the HomePod and its smarter array of microphones to listen for what comes next. It's better, more dedicated hardware to help the software deliver a better experience.
It's great that one device can do everything, but we rarely want to use one device to do everything when we don't have to. Especially because human memory is contextual and spatial it becomes easier to remember where we "left" things if they are on different devices in different places.
Especially in TNG it feels like a lot of the screens are designed for exactly that: the screens can change to other displays but most often don't because they are very specifically tailored to each specific place they are. That seems somewhat intentionally designed to help the human memory and better muscle memory, knowing what we knew in the 90s and knowing what we know today. "I don't want to lose my place in this recipe just to set a timer or to catch up on TV" is a human problem and TNG showing "I don't want to lose my place on this PADD so I'll ask the computer to do something or walk to engineering to touch a specific dedicated panel that my fingers have already memorized" is maybe just a reflection that in Star Trek's future humans are still, you know, human.
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"
It doesn't come with nearly the same level of implausibility (causality problems) that FTL does IMHO.
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?'
But yeah, the story went pretty much like this. I prefer that second episode much more than first one with 33 minutes theme.
[1] https://www.technologyreview.com/2019/06/27/238884/the-penta...
> 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
Any active RF broadcasting device would function as a "look at me" homing beacon.
Therefore the ideas that this might apply to real-world situations and use existing WiFi infrastructure, are a stretch given the information that's been shared.
It basically doesn't seem like a big deal to demonstrate what has been demonstrated.
In principle, any packet that carries data can also be used for sensing, though, as you mentioned, this isn't what the researchers demonstrated. However, for years, this kind of thing was studied using special multi-antenna Intel cards to get a clean signal. Getting this level of accuracy from such a low amplitude signal from a single antenna on commodity hardware like an ESP32, is the actual breakthrough. It proves the concept is sound before tackling the much harder problem of using a standard home router amidst other traffic or isolating multiple targets in a room.
CSI does require a supported chipset, like an ESP-32. However, if an IoT device is already using an ESP-32, for example, one would not need to add dedicated hardware (like an mmWave MR60BHAX) to be able to do things like presence, breathing, heart rate, and location detection.
As a hobbiest/ESPHome user, I have lots of ESP-32s and not lots of mmWave-s. As a business, I'm already shipping with an ESP-32 and I don't want to increase my BOM.
Besides this, I find this research to be a big deal as it has implications for privacy and security. Your biometrics can be collected using existing widely-deployed hardware using existing internet standards. Your smart toaster can indeed be spying on you in more ways than you think.
But anyway, using CSI for sensing will soon be old hat. IEEE has granted approval to the 802.11bf WLAN Sensing working group to define standards for exactly these types of applications. Taking what's currently an artifact of an implementation detail, and turning into a first-class feature.
Edit below
I want to point out another thing: "clinical-level heart rate monitoring with ultra low-cost WiFi devices" can be lifesaving in situations where clinical-level heart rate monitoring is otherwise unattainable.
Ok.
> There is no indication in the article that the WiFi can actually be used for transmitting real data at the same time
So? No one said it was.
> Therefore the ideas that this might apply to real-world situations and use existing WiFi infrastructure, are a stretch given the information that's been shared.
What? First you say it's trivial/obvious, and now it's impossible? Decide on your critique.
Intel demo on commercial laptop (2022), https://news.ycombinator.com/item?id=45130061
Qualcomm human-in-home positioning demo (2021), https://www.youtube.com/watch?v=xNmnqCsvMTU
You can delegate to your doctor the right to delegate to other specialists without consulting you.
Other humans can delegate to the agents of their choice.
This is why the first step is for you to have control of your data, then you can specify/revoke who-does-what with it.
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 [...]
Marsrocky/Awesome-WiFi-CSI-Sensing#gesture-recognition: https://github.com/Marsrocky/Awesome-WiFi-CSI-Sensing#gestur... :
> "Real-time Cross-Domain Gesture and User Identification via COTS WiFi" (2025)
> "One is Enough: Enabling One-shot Device-free Gesture Recognition with COTS WiFi" (2024) https://ieeexplore.ieee.org/abstract/document/10621091 .. https://scholar.google.com/scholar?cites=5141488558554953622...
https://news.ycombinator.com/item?id=12353605
https://www.theatlantic.com/technology/archive/2016/08/wi-fi...
1: https://ieeexplore.ieee.org/document/7457075
> “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.
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.
> 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.)
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.
(100% of my foster kittens have survived (out of 25) and I specialize in fostering the worst cases.)
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.
