Using Radar to Read Body Language

Yet another method of surveillance:

Radar can detect you moving closer to a computer and entering its personal space. This might mean the computer can then choose to perform certain actions, like booting up the screen without requiring you to press a button. This kind of interaction already exists in current Google Nest smart displays, though instead of radar, Google employs ultrasonic sound waves to measure a person’s distance from the device. When a Nest Hub notices you’re moving closer, it highlights current reminders, calendar events, or other important notifications.

Proximity alone isn’t enough. What if you just ended up walking past the machine and looking in a different direction? To solve this, Soli can capture greater subtleties in movements and gestures, such as body orientation, the pathway you might be taking, and the direction your head is facing—­aided by machine learning algorithms that further refine the data. All this rich radar information helps it better guess if you are indeed about to start an interaction with the device, and what the type of engagement might be.


The ATAP team chose to use radar because it’s one of the more privacy-friendly methods of gathering rich spatial data. (It also has really low latency, works in the dark, and external factors like sound or temperature don’t affect it.) Unlike a camera, radar doesn’t capture and store distinguishable images of your body, your face, or other means of identification. “It’s more like an advanced motion sensor,” Giusti says. Soli has a detectable range of around 9 feet­—less than most cameras­—but multiple gadgets in your home with the Soli sensor could effectively blanket your space and create an effective mesh network for tracking your whereabouts in a home.

“Privacy-friendly” is a relative term.

These technologies are coming. They’re going to be an essential part of the Internet of Things.

Posted on March 8, 2022 at 6:01 AM19 Comments


Winter March 8, 2022 8:32 AM

@Peter A.
“Just another ubiquitous EM radiation source”

Compared to the sun, this is an entirely negligible source.

Clive Robinson March 8, 2022 8:35 AM

@ ALL,

“This kind of interaction already exists in current Google Nest smart displays, though instead of radar, Google employs ultrasonic sound waves to measure a person’s distance from the device.”

Either EM/RF or Ultrasonics can be used to “image”.

Other things being equall, the resolution of the image depends on the wavelength of the radiant signal, not it’s frequency.

The speed of light is roughly 300,000,000meters/sec sound in air at sea level preasure about 300meters/sec. So for the same wavelength EM/RF has about a million times the frequency of ultrasonics.

Human flesh however is “soft a squishishy” and made of a lot of fat and water with molecules ending in -OH which makes it a good absorber or poor reflector of both EM/RF and ultrasound signals.

Which just happens to mean that you will be easily able to detect such signal sources before you get into their detection range.

On the flip side, many building materials are close to being transparant to EM/RF signals, BUT not to Ultrasonic signals. Which means for many reasons for “detectors” ultrasound would be perfered, but for actual surveillance by third parties, EM/RF would be prefered.

It’s why you can make “look through wall” imaging equipment with already existing WiFi AP sources…

If you are looking to enhance your privacy, it’s not just Farady screening you need, you also need absorbers for both RF/EM and ultrasound.

Supprising to many you can buy that aluminium foil covered expanded foam “thermal home” insulation that does limited screening for EM/RF and some absorbing of ultrasonics. With the advantage it’s use by you is not realy suspicious.

Ted March 8, 2022 9:06 AM

From the article: “I imagine my smart display turning into a giant stop sign when it realizes I’m heading to the snack cabinet at midnight.“

My first question: How do I turn this thing off?

Quantry March 8, 2022 11:28 AM

Hi Ted. Re: #comment-401412

Apple already uses Bluetooth_Low_Energy irrevocably on all their phones, OSTENSIBLY for their beacon protocol, I’m told [1]:

Unless, I suppose, you have the savy and grit to open your $TooPRICEY phone and gut the bluetooth radio, AND as Clive reminded us, also the ubiquitous “existing WiFi sources” emanating from every phone and router and camera near you… ad nausium…:

“Holographic imagery” made from these nice stable sources are here to stay:

“Wireless data transmission systems such as wi-fi or Bluetooth emit coherent electromagnetic waves with a precisely known amplitude and phase. Propagating in space, this radiation forms a hologram — a two-dimensional wave front encoding a three-dimensional view of all objects traversed by the beam.” – h–ps://

Stalking and Imaging by interferometry are too compelling to “switch off”.

Of course you can always opt for jamming with white noise [2], where its “legal” [3]. ;p Try the always fun 555 timer, or the random hxxps:// running hxxps://

Or just use the foil hat, Luke.

[1] Apple iPhone is the “The Most Sophisticated Spy Machine Ever Made”- Rob Braxman Tech (cant find the UTUBE link)
[2] hxxps://
[3] hxxps://

Humdee March 8, 2022 11:38 AM

I read this post immediately after reading the new research that claims we can now have an app that decodes the emotions of pigs.

So I’ll say it again. Philosophers claim that humans are just clever, complex animals. At what point in time are we willing to drop the adjectives and admit Orwell was right? All animals are equal, some more equal than others.

Ted March 8, 2022 12:46 PM


Is any BLE data stored? Does this fall under the purview of privacy laws?

It’s crazy because Google’s Nest Hub can apparently use their radar technology, Soli, to monitor your sleep. The feature is called Sleep Sensing.

It monitors your respiratory rate while sleeping, and if it’s consistently not in a recommended zone, flag it to your physician, as problems can range from heartburn to sleep apnea.

Nest Hub also uses microphones, light sensors, and temperature sensors. Okay, beyond privacy, how much does HIPAA or even the FDA come in to play here?

I’m sure it’s an interesting feature if you want it. But that kind of granular monitoring at the consumer level is amazing. And by amazing, I mean I was surprised.

Peter A. March 8, 2022 3:11 PM

@Ted: back in TechUniv days the running joke about EE projects was that someone has been assigned an electronic toilet seat controller that should control the flushing process; a longer version of the joke said it shall also measure various aspects of the “user output”, gather trends and statistics, and print a report for the physician. But it was before the Internet got here.

Today we’ve got all kind of vital functions monitoring devices that constantly send data “to the cloud” for God knows who to see and process. Wearable ones are half-decent, because you can choose to wear them when you actually need them – or not at all. And now remote sensing comes into play – not in specialized medical devices (like a Holter monitor I got once, but it was a recording-only model), but in everyday consumer electronics. Funny times.

Over here the prescriptions are all-electronic already, no way to get a prescription drug (more and more trivial drugs are prescription-only) without it being recorded in a government-controlled database. Very few practitioners still keep paper records only.

vas pup March 8, 2022 3:14 PM

Time and again:
With ANY new surveillance technology in device you bought, YOU, not manufacturer or/and ‘collective O’Brien – 1984’ should in charge of the choice use it or disable it with kill switch up to your own discretion.

Just good short video from BBC related to privacy

In our surveillance obsessed society we should have blinds blocking any Electro- Magnetic based surveillance technology, e.g. cover by aluminum foil. It is better to be safe than sorry and adjust Your behavior to existing privacy violation paradigm by mean of technology rather than legal system.

vas pup March 8, 2022 3:56 PM

German intelligence agency allowed to investigate AfD, court rules

“In a blow to the right-wing AfD party, a German court sided with Germany’s internal intelligence service and said the agency was justified in its decision to classify the party as a “suspicious entity.”

Wow! First of all, Court made decision not intelligence agency by itself.

That is surveillance related – informants is just human surveillance tool:

“Labeling the AfD as suspicious allows the agency to use intelligence-gathering tools, such as informants, in order to keep tabs on the party. In practice, though, there are additional legal disputes to solve before such tools can be implemented.”

“The judges focused on AfD’s controversial “Wing” (Flügel) faction, which was officially disbanded two years ago, saying that its leaders still wielded considerable influence in the AfD. It also pointed to the party’s youth organization JA and its activities.

===>The court found that both for both of these groups, an understanding of the German nationality rooted in ethnicity was a primary political goal. This is a belief that Germans “must be preserved in their ethnic condition and ‘foreigners’ should be excluded as much as possible,” the court found, while also pointing to “xenophobic agitation.” It said that such ideas were contrary to Germany’s constitutional definition.”

Very good example to follow and not support groups with similar ideology around the globe.

vas pup March 8, 2022 4:05 PM

WE should not forget COVID is still up

Carnival spread COVID in Cologne — again

“The German city of Cologne’s Carnival celebrations raged on as normal late last month, barring a few restrictions. Now the city at the heart of the holiday is facing COVID-19 consequences.

A week after the end of the festival, Cologne is seeing a sharp rise in the seven-day incidence rate of COVID ==>infections — 56% higher than the national average.

This year’s Carnival event followed national COVID protocols and included added measures aimed at reducing possible spread.

“The city of Cologne decided that it is better that people celebrate under official terms than at private parties without restrictions,” Blümcke wrote.

Over the six days of official Carnival celebrations, the city operated as an “area for traditional festivities.”

The country’s 2G+ rule, which requires a booster vaccination, double vaccination or proof of recovery along with a negative COVID test, was enforced. While masks were not required outdoors, random compliance checks were ordered throughout the day.

Pub crawlers and others attending indoor events were asked to provide additional proof of a negative COVID test.

Still, despite the city’s efforts to ward off spread, COVID infections are on the rise.

==>Rates are especially high among 20-29 year olds, who are currently displaying a seven-day incidence rate around 118% higher than the national average.

The University Hospital of Cologne is also feeling the fallout from rising infection rates, with 689 employees infected or in quarantine.”

Clive Robinson March 8, 2022 4:56 PM

@ Ted, ALL,

Is any BLE data stored? Does this fall under the purview of privacy laws?

It depends on what jurisdiction you are in to a limited extent.

The real problem is thay legislation is generally quite a few years if not multiple decades behind “Societal mores”.

Then there is Law Enforcment “Kick Back” the result is nearly all bio-metrics are considered “public” not “private” information.

It is the “if we can see it it’s public” argument, even if they have to use a fiber optic camera to get around air conditioning ducts etc, they claim “on public view” even if they are trespassing in the process[1].

The ability to maintain your privacy against such intrusions is involved. So much so it can be made out you are either paranoid or have something to hide or both by prosecutors. Apparently judges are not keen on counter argument to such nonsense so in the US you right to be secure in your papers, person etc slides even further into the impossible to achive area.

We hear frequently the “going dark” nonsense out of Law Enforcment, and that is exactly what it is pure nonsense, all the actually verifiable evidence not hand wavery claims point in the direction that Law Enforcment have way more access to electronic communications than they can possibly handle…

People should call them out every time on it because making such a false claim is legally very awkward ground and can lead to significant issues not just for the individuals involved but their agencies and employers, be they direct or indirect[2].

[1] A friend is quite involved with drones in the US, and apparently US Law enforcment hold the view that as long as they do not touch the ground it’s “public air space”, so a drone flying outside your window to find a chink in the blinds or curtains is not trespasing, nor if it flys a probe in through an open window… Similarly if they illuminate your home with killowaTts of EM or other radient energy as long as you can not see / feel / hear it then it’s not giving you cause to make complaint…

[2] It’s actuallt making a known “false statment” in an attempt to “achieve a pecuniary advantage” for an individual or organisation aka fraud. Further as it is made “in public office” it is either misfeasence or malfeasance. The former being a tort, has much lower burden of proof, and alows for significant financial damages.

Also of interest is the “outsourcing” of government obligations to private third parties does not in any way absolve the government of responsability, but interestingly it does remove “Crown Immunity” from the outsourced function… Because the Government still retains the legal ability and right to sue a third party supplier of goods and services for nonfeasence, misfeasence or in some cases malfeasance. So “The Crown can not sue the Crown” argument nolonger holds.

Denton Scratch March 9, 2022 6:12 AM

They’re going to be an essential part of the Internet of Things.

That struck me as an odd remark. I don’t see why radar tracking of humans is an “essential” part of IoT; and I don’t believe IoT is “essential”, unless you scope “IoT” to include WiFi access points and mobile phones.

It annoys me that phones have become “essential”; increasingly, I find that online services won’t let me sign-up without a mobile number. I have a landline DECT phone. I do own a smartphone, but it’s not “mobile” – it just sits on my desk, near my landline. I never take it for a walk. Its battery now holds about a quarter of the charge it held when I bought it. Meanwhile the DECT phone never seems to deplete its battery at all.

A new battery for the mobile (a Nokia) would apparently cost me almost as much as a new cheapo smartphone. I guess I need to buy a dumbphone, aka. “festival phone”.

Quantry March 9, 2022 10:00 AM

Hi Ted.
“Lawful” is not the equivalent of “Moral / Righteous”. (re #comment-401420)

Yes, evidently the BLE standard allows for a global location surveillance mesh network, if you thread the loopholes the way Apple evidently has. So, to answer

“how do I turn this off” [legally, aka without massive spectrum-spread RF jamming noise [1]…]

sign below

I, the undersigned wearer of a tin hat, believe that Apples usage of the BLE standard is an abuse of Radio Telecom privilege.

and when you gather 3x(10^5) such signatures from your country-men send those to the correlative “parliment” and wait for 30 years. Alter and resign and resend for the thousands of abuse cases, all of which enable “exceptional case [2]” abuse AFTER the envisioned revision.


“how do I turn this off”

hm, more broadly, (including Bruce’s radar problem above), I was pondering what effect a swinging disco ball might have. Truth is, laws are society’s intense crucible for “a select hated few”, not “their beer drinking buddies”.

[1] Last night after stating that Spark-gap jamming is illegal, I went home to a major increase in the BLE scan interference that my girl-friend has been suffering with her ear-buds over the past months thereby compounding other attacks.

I suspect there is a way for Apple to increase the scan wattage in remote iPhone locations, and I suspect there is a back-door for hire to make it happen beyond what the BLE standard defines as “Low Energy”.

[2] What exorcist would you hire to if it IS claimed to be “exceptional” after all that?

Ted March 9, 2022 1:03 PM

@Quantry: “I, the undersigned wearer of a tin hat, …”


@Peter A.: “Very few practitioners still keep paper records only.”

Yes, it’s wild to think how much has changed. At my work, they scan loads of paper documents into electronic files. They are retrievable via an ID #.

The company is big enough, and I’m sure regulated enough, that their security efforts seem mature – from what limited insight I have. It’s another question if all these crazy consumer “smart” devices are overseen with serious scrutiny.

@Clive: “so a drone flying outside your window to find a chink in the blinds or curtains is not trespasing…”

Shock. No awe. Jurisdiction and intent seem relevant. Glad we live in places with a moderately free press.

Quantry March 11, 2022 11:21 AM

Grand observation Clive:

outsourcing” of government obligations to private third parties …does remove “Crown Immunity” from the outsourced function…

Now “ya” just need a billion $CDN to sue the Crown, and a lawyer that wants to loose.

@ jer, the “Soli” tech seems to be radar, operating at 60GHz: (visible at high mach 🙂
(replace xx with tt ) hxxps://

Ted, here’s the bluetooth Core spec, but Apple isn’t likely to say what info they are gathering from their use-case.

Regarding the Apple beacon loophole / backdoor I suspect is being used:

BLE Power Control and Interfering Beacon traffic, starting in paragraph 3.8 of the Core Spec (5.3):

“In LE, a device can request a remote device to make a specified change in the remote device’s power level…”

and“When advertising interval values of less than 100 ms are used for non-connectable or scannable undirected advertising in environments where the advertiser can interfere with other devices, it is recommended that steps be taken to minimize the interference.”and

“ Periodic advertising events:

The Periodic Advertising Interval is the interval between the start of two scheduled AUX_SYNC_IND PDUs from the same advertising set (even if the PDUs are not transmitted for some reason). The Periodic Advertising Interval shall be an integer multiple of 1.25 ms in the range 7.5 ms to 81.91875 s”

This frames perfectly, albeit circumstantially, the intense packet interference in the form of a regular 80db (ish) pulsed audio artifact (“chirp”) my friend was putting up with using bluetooth earbuds with her iPhone, on a remote acreage. Oddly, it went silent the day after I mentioned my suspicion here, for the first time in months.

ThreeRs March 14, 2022 8:33 PM

@Clive, @Ted: “so a drone flying outside your window to find a chink in the blinds or curtains is not trespasing…” and “…apparently US Law enforcment hold the view that as long as they do not touch the ground it’s “public air space””.

Due to railroad land grants in the 1800’s, a fair amount of the US West is “checker-boarded”, where public and private land is intermingled in 640 acre sections making a nice checkerboard grid on paper. In theory, the public can travel across the “corners”, moving from one section of public land diagonally to another. In practice, its not that simple. For some hunters in Wyoming, it led to criminal trespass citations, due to violating the airspace of the private land owner in the adjacent sections.


“Like other Western states, Wyoming has no statute explicitly allowing or prohibiting corner crossing. Opponents say it’s a problem because even if the land isn’t physically impacted, invading its airspace erodes private property rights.”

For reference:


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