QuadRF can spot drones and see WiFi through my wall
jeffgeerling.comOne day I want to build something like this, except for sound. It would be great to get a heading and distance for where a sound is coming from.
This could be both for small scale things (e.g. which part of this is squeaking?) or large scale (e.g. is that booming noise coming from the construction a few blocks away?)
Fluke has made an acoustic imager for a while now. It is used for detecting leaks:
https://www.fluke.com/en-us/product/industrial-imaging/fluke...
There are a few knockoff options too, which are not quite as nicely calibrated, but get the job done for much less than Fluke-level prices. Like the FOTRIC TD2.
I think a few people have made homebrew versions too, like this one mentioned on HN: https://news.ycombinator.com/item?id=45137584
Not sure if you've heard of them, but they're starting to come to market with this exact thing aside from distance detection and more on the "which part is squeaking" side.
The army has one of these for sniper triangulation, and Boeing made a civilian version for optimizing sound dampening on the 787. I don’t know if they kept doing that on subsequent planes but I would expect so given how enthusiastic they were about being able to apply the weight budget to greater effect.
You need really high clock rate sensing to differentiate the arrival time for sound from microphone arrays where they are all less than a nanosecond separated from each other.
ChatGPT tells me that it would take a very large array to detect distance with any accuracy
I think you'll be very interested in this awesome project
There are products in this space, eg https://www.crysound.com/
Very cool stuff, can be used for drone detection at up to 200m. Accuracy is not super good, unless you make mic spacing a bit large.
Like in this Steve Mould video, "Acoustic cameras can SEE sound" [1]?
I've seen http://soundryx.com/
I just kinda skimmed through it, so it detects drones in sky? Am I understanding this correctly? That might have some defense application considering what's going on in Eastern Europe right now.
It detects drones which send out RF signals at the same frequency band. Most drones used in Ukraine are tethered with thin optical wire exactly because one of the first anti-drone measures was to simply jam them at the frequencies the operators used.
There are some more advanced anti-drone measures at work: Like blasting them with directed high-energy microwaves to destroy the circuits.
Frequency hopping is not THAT difficult.
Brute force wide band jamming would be easy too and would make hopping ineffective. Unless drones use self tuning antennas to overcome losses, they can't hop too far away from the antenna resonance frequency, which makes jammers job easier.
Most drones aren't optical because optical drones sacrifice payload and distance, they're only used when broad spectrum jamming is expected. Jamming of that type is expensive and heavy enough that infantry probably won't be jamming, or light vehicles, or a lot of infrastructure.
> That might have some defense application considering what's going on in Eastern Europe right now.
This is a bog-standard phased-array RDF calibrated for WiFi freqs; that stuff is already in every single defense show.
Also, that's why there's jamming everywhere (to blind that kind of things) and why many UAVs are now tethered to optical fibers instead of being RF-controlled.
Very much so.
I had a friend who'd just gotten out of EE school as a non-traditional student who was working for a company that was making radars for tracking drones maybe five years before the 2022 Russian invasion.
That was an active system, similar in concept to the radars used in air defense system just scaled down and faster acting.
The one in this article is a passive system that sees the transmitter on the drone. The comm link is the obvious weak spot on the drone as it can be detected and jammed, it is fairly inevitable that lethal attack drones that work anonymously will be widespread as a result.
> that sees the transmitter on the drone. The comm link is the obvious weak spot on the drone
Isn't most drones run by fiber optic nowadays around the front-lines though? Can't really jam those, but maybe still detect it somehow?
The visualizer reminds me of my thermal camera.
I have heard claims of devices (mostly TVs) supposedly coming with secret 5G cell uplinks built in [never heard a specific model mentioned though].
If there were more variants covering more commonly-used RF bands, people could walk around and literally check for once.
(incidentally i'm sure three letter agencies have had this sort of tech in their bug-detecting toolkit for a LONG time)
Whos paying the telcos for those 5G connections and also has the FCC been degraded so much that they would allow for undeclared radios in consumer products?
More likely 4G LTE MTM (https://www.verizon.com/business/products/internet-of-things...). It's dirt cheap and paid for by the vendor of the device it is in (usually) in the name of 'telemetry'.
I've seen so many random industrial devices and parts come into our plant that have their own cellular it's wild.
You really think these are in TVs going unoticed and someone is paying for each radio?
I have $100 devices in industrial devices that have them. In bulk, they cost next to nothing (not quite as cheap as RFID but getting there).
Secret 5G is not as common because there is a huge incentive to resell the free service. Maybe with eSIM it will be harder. Kindles uses to have a free data plan SIM.
My truck (Ford) has some cell connectivity that I’ve never paid for. At scale it’s likely very inexpensive.
Telcos sell off peak only 5g for cheap. Only to large companies that are willing to work with the limits. Often it is low bandwidth.
The FCC is literally powerless nowadays for all intents and purposes. They've abrogated so much of their authority to the states now that they might as well be eliminated. What little authority that remains with it is bought and paid for to the point that I'm sure you could get anything "approved" if you wanted.
> has the FCC been degraded so much that they would allow for undeclared radios in consumer products?
Well... most TVs already have a WiFi/BT chipset for stuff like advertisements or, especially with Apple, high-bandwidth video streaming. There is already a radio module present, but (IIRC) you don't have to disclose what exactly that module is capable of.
You definitely are required to disclose what frequencies are used and at what power.
Uhh yes you absolutely do need to disclose exactly what each is capable of. Each radio must itself be approved by the FCC and documented
Build this into smart glasses and it would be fascinating.
This has me thinking that fiber optic drones using this technology might be able to discover the location of signal-jamming equipment. But only for the good guys.
The visualizer app reminds me of the same UI / output you get from acoustic cameras.
I wonder if this tool can help with EMC compliance testing. My TinySA needs an LNA, so I wonder if this has the required noise floor.
I don't think it's any good for that. It's relatively narrowband and not the frequency you usually have issues with EMC on (5 to 6GHz - unless you are specially transmitting on this frequency you are unlikely to emit anything there).
I don't see any professionals turning to this for EMC/EMI testing, they already have all the test equipment for that job.
How about "non-professionals"? It could be useful to check device before sending for pre-compliance / compliance checks and save money - that would avoid very expensive iterations.
But there are already benchtop or handheld signal analyzer for that purpose.
This seems more like a tool for checking across entire large assemblies like an entire building, car, aircraft, etc, for unknown sources. If you have an individual discrete device that you're already testing, just using traditional instrumentation seems reasonable, but on a large, complex assembly, I can see it being useful. Also useful for things like detecting if a particular antenna is working without actually going up there to measure near it; if you have a MIMO setup with multiple antennas, this might make it easier to check if all of them are working correctly when mounted in inconvenient areas.
That's absolutely missing the point. EMC/EMI testing is expensive, time consuming and requires scheduling and experiment design.
Being able to do local soft-run testing on-site to be sure that you eliminate the easy 90% of issues before you get to the lab would be a huge win.
I think that for a single device, this probably wouldn't help much over just having a more traditional signal analyzer, either benchtop or handheld. If you know what you're testing, just using a signal analyzer around it will give you a good first pass picture of emissions, and probably be much more informative and precise than this.
This seems more useful for finding unknown or hidden RF sources, for instance looking thorugh an entire building to find unknown RF sources, or maybe a whole complex assembly like a car or aircraft.
Historically these have been quickly shut down without much of an explanation.
Please elaborate. There are literary step-by-step videos on how to build these. E.g. https://www.youtube.com/watch?v=g3LT_b6K0Mc
Phased array radars are export controlled in the US. It doesnt mean its illegal to build or own, but it might be illegal to sell in some cases
I thought I remembered even seeing public Git repos with passive radar code that ended up getting shut down due to export controls?
Yeah, Kraken SDR removed some functionality due to these concerns, if I remember correctly.
Odd, because export controls don't generally apply to published material (like open source software), but maybe they were worried that because they were also selling the hardware they could have issues due to the combo being export controlled.
As someone who works daily with export-control-adjacent hardware and software, my experience is that people tend to aggressively self-censor to a far higher standard than export control regulations actually require. The perceived headache of drawing the ire of whoever it is the enforces this stuff (which as I type this comment I'm just realizing I don't know who specifically is responsible for that) is so scary that people don't want to take any risk at all of being targeted.
If you don't self censor in these cases the law will find you somehow. How change so they get you next time.
Not always, but pgp wasn't exported that way until not long before there was good demand for for encryption in e-commerce anyway
Wonder which LLM would be happy to vibe code it back (not sure if it would be able to pull it off tho).
The covered materials are very broad, though often limited to equipment built "for purposes of", like in this section.
Title 22 Chapter I Subchapter M Part 121 - The United States Munitions List - Category XI Paragraph b
Electronic systems, equipment or software, not elsewhere enumerated in this subchapter, specially designed for intelligence purposes that collect, survey, monitor, or exploit, or analyze and produce information from, the electromagnetic spectrum (regardless of transmission medium), or for counteracting such activities.
At what point does a microphone become an intelligence device, when we have so many types of microphones. Is it an arbitrary label I can add or remove to a product? Will it apply equally to large manufacturers?
Do share some more details please
The explanation may be spelled ITAR.
Neat! SDRs have been available at reasonable price points for some time but the processing power to engage with wifi and other digital signals has been somewhat elusive. Assuming RAM can be purchased in the future, I think we might see a lot more prosumer-targeted devices for doing raw signal analysis in the future.
Do you have specific SDR in mind? I thought the v2 dongle doesnt have the range of Wifi? SDR is something Ive just recently want to learn to help me understand electromagnetism
I recall reading the original research paper from a student who made the same RF ‘camera’ here in hacker news.
It should be more specific, it spots RC drones operated on ~5.8ghz, it won’t spot RC on 900mhz, nor cellular enabled ones.
It also appears to have a fairly narrow detection angle. This might work for spotting a drone when you already know roughly where it is, but that problem becomes infinitely harder when you have to scan the entire sky.
RF drone detection has been a challenging problem for quite a while. Lots of solid state radar/RF detection products have emerged in the space, but it is not a trivial problem. And that is for drones with active RF comms, anything flying autonomously is even harder to detect at a far enough range to actually do something about.
> RF drone detection has been a challenging problem for quite a while.
Correct, there is no bullet proof cuas system to this date.
> anything flying autonomously is even harder to detect
Not just autonomously, because even in autonomous mode you would still need other RF like gnss, but you can fly drones without any rf signature at all and utilize a pre captured images saved on board to navigate the drone accurately using its cameras (normal or thermal). In this case, rf interference won’t work, it won’t be detected based on rf signature either, you will have to rely solely on visuals and acoustic, fly at night, and only left with acoustics.. it is a very hard task from technical standpoint.
Is that a limitation of the antenna? I though QuadRF uses SDR so can see many frequencies, not just the wifi things like ESPARGOS [0]
From documentation, QuadRF: Operating frequency range of 4.9 - 6.0 GHz (C-Band).
Not the antenna, unfortunately, it only operates on the range of 4.9-6ghz.
It would be great to have a wider range like other SDRs but of course the cost will increase exponentially.
for lack of directonality?
for lack of frequency tuning
> It sounds like they had to reverse-engineer the MIPI protocol used on the Pi 5 to do this (since it goes through the RP1 chip), and the way it's architected, you can daisy-chain multiple QuadRF modules together, letting each module calculate it's own phase shift.
How are they planning on distributing a shared, highly precise clock for that purpose? That's already a PITA if you do QO-100 modes that need high precision, but usually there it's enough to have one good clock that you feed to the LNA... but here? Every single one of these modules needs a very precisely identical timing signal and the kind of chips you can use to multiplex a reference clock signal are pretty expensive.
Sigh, fine. I will buy another radio gadget on crowdsupply.
I was almost through the checkout flow last week before I realized that this configuration only supports a relatively narrow frequency range.
I work primarily in sub-GHz radio. Please wake me up when they launch their LoRa version, that would be an instant purchase for me.
And yet since rtl-sdr times we have passive radars as an option as well https://www.rtl-sdr.com/tag/passive-radar/
The original quote for a single tile was $50-$100
They came out at $500
Being off by a bit is fine. Being off by 5x to 10x is.. Yikes.
Prices have gone a little insane in the last year though too to be fair to them.
The Pi alone... just today, someone over at Reddit spotted a Pi 5 being sold for 350$ [1].
[1] https://www.reddit.com/r/homelab/comments/1uso8u1/insanity/
I thought that might just be Amazon resellers capitalizing on marks being too lazy to go off site at first when they were $280 at Microcenter (still crazy expensive). [0] Then Adafruit had them for the same $350! [1] And it really does seem to be driven by the ram too the 4 GB model is only $130 (or $104 at MC).
[0] https://www.microcenter.com/product/702590/raspberry-pi-5?rd...
Just like eBay, an Amazon listing for a certain price does not mean the item is actually /selling/ for that price -- especially with badly-coded dynamic re-pricing algorithms hooked into listings these days.
It looks like it has 4 tiles on it, no?
Yea its mimo 2x2.
Point still stands that they initially said it would be $50-$100. And its going for $500.
I mean if a single tile is 50-100, then 4 is 200-400, so it's not that far?
if it can spot/track drones that is a marketing opportunity for airports around the world that have to deal with drone nonsense which shut down flights for days
Most major airports will already have a counter-UAS system, it's a huge industry.
One big issue with radar is that it has the same problem pilots and human observers do: it struggles to distinguish drones from anything else in the sky (birds, balloons, planes, etc.). This is an active and improving research space, but by and large with radar, when your pilots report a drone, you still don't know how to figure out if it's the typical mis-identification or something real.
I'm reading about pilots spotting drones during takeoff/landing that the airport didn't know about
And I've read about airport shutdowns in UK and US without a single arrest which is why it keeps happening
So whatever system exists, apparently not good enough
If would likely need to track them well (not sure from this article/video if that's the case?) to be useful in that scenario...
Drawing a splodge in roughly the location (not sure if there's range info either? I doubt it if it's passive) overlaid on the video likely won't cut it...
Yes, primary radar has been useful for detecting airspace incursions since 1939. Nothing new here.
The difference with this kind of tech, though, is tracking down the operator.
Phased array antennas (in use since the 1960s) and AESA (in use since the 1990s) are very mature tech that RF engineers are well aware of.
This gizmo is primarily interesting that it's pre-packaged at a price that hobbyists can afford.
Only the ones that use radio for control. The fiberoptic ones are "dark" to this setup.
There are more way advanced systems for cuas, where they infuse radar and visual and acoustic plus now AI to minimize the false positives, but practically speaking, they are not bullet proof and still fail. RID (remote ID) is a way to have a cooperative communication and was mandated in US, but there are ways too to spoof it and cloak it.
Yeah RemoteID is trivial to spoof using an ESP32. Most hobby pilots I know simply don't comply with RemoteID. And bad actors certainly won't purchase a $75 device to add to their drone.
It does become a bit more difficult with consumer grade off the shelf drones because it's built in. Still defeatable by the determined of course.
> If the open source community can come up with something like this, just imagine what governments are capable of.
Since ~2022 and accelerated by the Russian aggression against Ukraine, governments are now behind both private and open source for frontier technology.
The companies that captured government contracts in the last century can’t move fast enough to bring tech into the government and national technology policy and funding is collapsing compared to the private sector
That’s new in history
Open source is the future. If everyone can work on it, we get better results for cheaper.
Open source doesn't mean the end of competition, since we are a competitive species.
I think the future economy is going to be some sort of UBI + large open source projects