[HN Gopher] Show HN: RF Hunter - Find hidden cameras and other d...
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Show HN: RF Hunter - Find hidden cameras and other devices
This project is an RF Signal Scanner built using an ESP32, AD8317
RF detector, and various other components. It's designed to detect
and measure RF signals in the environment and display the signal
strength on an OLED display. It's useful to find hidden cameras,
wiretapping devices, and other RF-enabled devices.
Author : RamboRogers
Score : 414 points
Date : 2024-10-24 00:21 UTC (22 hours ago)
(HTM) web link (github.com)
(TXT) w3m dump (github.com)
| Terr_ wrote:
| Is the ESP32 mainly to drive the LCD display and provide a
| numeric readout, or is it also needed to control the sensor-side
| so that it cycles through different settings and frequencies?
| RamboRogers wrote:
| It runs the screen and reads the sensors, you can see it in the
| code.
| transpute wrote:
| Thanks for making this public. What's the ballpark BOM cost?
|
| Could a directional antenna help with locating RF sources?
| There's some older work ("WokFi") on parabolic antennas for WiFi,
| https://web.archive.org/web/20140802123553/http://www.usbwif...
|
| Here's another circuit design for AD8317,
| https://g8rwg.uk/articles/noise-meter-ad8317/
|
| _> The AD8317 module I'm using has the logarithmic slope set to
| 22mV /dB. I used the output of a Viavi JD785 at different
| frequencies to check the slope and dynamic range of the device.
| Linearity and dynamic range at 1GHz and 3.5GHz is good and as
| expected drops off at 144MHz and 6GHz._
| pragmatick wrote:
| > What's the ballpark BOM cost?
|
| https://github.com/RamboRogers/rfhunter/blob/master/rfhunter...
| contains amazon links. About $100 although many of the required
| components come as packs.
| bobmcnamara wrote:
| Generally, directionality is tricky to do handheld over a wide
| bandwidth.
|
| Another approach is a phased rx array, could even be as few as
| 2 antennas, and from that you get a bearing too.
| kubectl_h wrote:
| What is the sensitivity/range? I've always wanted something like
| this to carry in the woods to detect game/trail cameras. Not for
| any nefarious purpose, but to get an idea of how surveilled the
| woods are.
| etrautmann wrote:
| Don't many of those just store data locally?
| kubectl_h wrote:
| Oh duh, yeah you are right. I had swapped RF and IR in my
| head for some reason when I was scanning the project page and
| thought this was somehow picking up signals based off noise
| from the sensor. Might be time for bed for me.
| ffujdefvjg wrote:
| Game cams with cellular modems are getting to be pretty
| common, and you can equip them with solar panels. Basically
| just set em and forget em. It wouldn't surprise me if this
| is making them much more common...you can get them deep
| into the woods and don't have to go check on them hardly at
| all.
|
| https://www.forestry-suppliers.com/c/trail-game-
| cameras/3-30...
| A4ET8a8uTh0 wrote:
| Sigh, it used to be at least woods offered respite from
| ever-present cameras. I am starting to think I should
| stop trying to fight the impending 'Transmetropolitan'
| future.
| jamil7 wrote:
| Game cameras are truly pathetic.
| defrost wrote:
| Some applications are, sure.
|
| The cameras themselves are useful for catching remote
| area | rural thieves on mine leases, rural properties,
| etc. They're great for spotting and counting rare and
| endangered species to better direct conservation efforts.
| ffujdefvjg wrote:
| Quite a few people dumping their trash in the woods
| illegally have been caught in my area with them.
|
| They just need to outlaw private citizens putting them on
| public property without a permit. Big fines could be a
| deterrant. Maybe USFS/BLM/NPS employees need some
| sniffing devices. The upshot is that if it's got a
| cellular modem, someone's paying a bill and they can
| usually be found pretty easily if you have the modem.
|
| With fire seasons going the way they are west of the
| Rockies, I'd be a little concerned about a bunch of lion
| batteries scattered through the woods. Just takes one of
| them to blow up in late summer (say it gets crushed by a
| tree) and there's a good chance it'll be a multi-billion
| dollar problem that kills people.
| potato3732842 wrote:
| Pretty much all the C and D rate state forests, nature
| preserves, etc, etc, in my state were only ever having
| their trails maintained by the "nominally illegal but
| nobody actually cares" SxS and ATV riders because the dog
| walkers and the hunters are much less averse to going off
| trail and even if they weren't they aren't packing a 15lb
| cordless chainsaw around to clear whatever fell on the
| trail.
|
| Karens with game cams have done a lot to curtail this.
| toss1 wrote:
| Agree, if you are talking about hunters (and I feel the
| same about fish-finders). To them: dude, if you're going
| to hunt or fish, don't just cheat, learn the craft.
|
| For my purposes, I've found a game camera extremely
| useful for finding what and when various critters are
| eating the garden and other plants in the yard, and to
| figure out what discouraging and diverting measures
| actually work. I also get a few pretty cool wildlife pics
| I'd never otherwise get.
| themaninthedark wrote:
| So just curious; if a hunter has a limit of 1 buck and 2
| doe but he really only needs 350lbs of meat, so either 1
| large buck and smaller doe or all 3 if they are smaller.
| Should he give up using the trail camera and the
| knowledge of if there is a large buck out there and just
| kill the first 3 deer he comes across?
|
| Another question, do you look up salary stats on
| Glassdoor, etc before you consider open position or
| asking for a raise? Would you consider it offensive if
| someone told you to stop cheating and just learn to
| negotiate better?
| kubectl_h wrote:
| Not to be pendantic, but if we are talking white-tailed
| deer, it depends on the population characteristics of the
| area you are hunting. In many places in the US the game
| management departments would probably prefer multiple doe
| if you have more than 1 tag.
|
| Additionally if you are hunting for sustenance, as in you
| really need the meat, then you take the first deer you
| can find. Waiting for the ideal deer is a good way to not
| end with a deer at all, regardless of whether you have
| them on camera or not.
| potato3732842 wrote:
| Yes but since it's the woods and not a university computer
| lab the only other noise source should be your personal
| devices so the noise from the "sleeping" camera should be
| pretty easily detectable even when it's simply looking for
| motion.
| RamboRogers wrote:
| This is dependent on the antenna. With a short 915 mhz antenna
| it picks up stuff 50 feet away. It auto calibrates on boot so
| if you're in the woods I bet it would work really well. Just
| make sure you turn it on without a strong nearby signal.
| o1o1o1 wrote:
| Interesting, thank you for sharing!
|
| Maybe somebody knows: Is there something similar for the Flipper
| Zero?
| RamboRogers wrote:
| I could make it I suppose.
| x______________ wrote:
| I've been lurking yc for a while and you inspired me to reach
| out to the community..
|
| This would be pretty awesome, please advise if there's
| anything I (or anyone) could do to support you in getting
| this logic onto a flipper (project support, testing, etc).
|
| -x
| RamboRogers wrote:
| Okay, I don't think it would be hard, most of the Flipper
| Modules use some sort of ESP module like an ESP8266 for the
| Wifi module.
|
| I've got a flipper right here. I find it cumbersome to use,
| but it's a pretty popular consumer product. I'll look at
| what the wiring cost could be to print a board. I've never
| done that.
| ghostpepper wrote:
| This is cool. Is is all point-to-point wired inside? I can't
| imagine a PCB design would be too difficult if all the RF stuff
| is handled by the IC.
| RamboRogers wrote:
| yeah, it's just soldered up to the pins. More details here:
| https://blog.matthewrogers.org/b/8BCF175A-6CC6-4E61-8310-A91...
| ffujdefvjg wrote:
| Cool project! I'd buy one of these if they were pre-assembled.
| RamboRogers wrote:
| Thanks, it costs about 30$ in parts. Not sure what a fair price
| would be.
| ffujdefvjg wrote:
| Not sure what the time/labor looks like, but I'd easily pay
| $60 bucks for that. You may be able to sell them at $100 and
| still move quite a few.
|
| Honestly if you dressed it up a little you could probably
| charge quite a bit, it's just a matter of reaching that
| audience.
| _dark_matter_ wrote:
| Agreed, I'd buy this at $100 for sure. I stay at a lot of
| airbnbs and am the kind of person who regularly checks
| those places for bedbugs.
| woleium wrote:
| i just disconnect the provided router in airbnbs i stay
| at. Turns out the host usually drops round all worried if
| there is a hidden camera.
| RamboRogers wrote:
| This is a great idea.
| bbarnett wrote:
| It's sad we're letting bedbugs return.
| tomcam wrote:
| Rule of thumb in manufacturing is 5x BOM costs. This comment
| will be downvoted but only by people who have not been
| associated with a successful manufacturer.
|
| I'd be happy to pay $150 for this.
| ffujdefvjg wrote:
| That...doesn't sound unreasonable.
| Eisenstein wrote:
| But does that work for putting together what are
| essentially modular pre-assembled boards? The RF detector,
| display, charge controller, and ESP are already consumer
| parts, and they are put together not unlike how a desktop
| computer can be built from retail parts. Would you say that
| 5x retail cost for the parts is fair for a custom built PC?
| RamboRogers wrote:
| Thanks for the info, super useful.
| declan_roberts wrote:
| A way easier solution to this is to turn off all of the lights
| and look around with your phone camera.
|
| The phone camera will pick up the bright IR lights that hidden
| cameras use to illuminate the room-- wireless or not.
|
| Obviously this only works if the camera uses IR lights, but
| pretty much all of the sneaky ones do.
| RamboRogers wrote:
| Well, maybe - it would need to have ir enabled. This also
| detects listening devices etc.
| mbreese wrote:
| Would this also be able to detect something like a camera
| that saves videos to an SD card to be retrieved later?
| Something that doesn't use WiFi or a radio?
|
| That's the main limit I see, but I'm wasn't sure if it such a
| device would still generate enough RF intrinsically w/o a
| radio.
| ddingus wrote:
| Maybe those could be found with a parabolic antenna and
| possibly an amp, ideally one with a limited range one can
| control via software.
|
| Once a few common signals are known, the software could do
| programmed patterns to ferret out easy ones.
| Ballas wrote:
| Most phone cameras have pretty steep IR cut filters these days.
| The front camera on most phones still don't, so you have to use
| that.
|
| That said, most of these spy cameras don't have IR
| illuminators...
| deknos wrote:
| do you have examples of cameras or smartphone which do not
| have IR filters?
| Ballas wrote:
| I don't but it's easy to test, just pick up a TV remote and
| press a button while pointing it towards the camera. It
| should look like a flashing white LED.
|
| I should also mention that both IR illuminators and TV
| remotes are usually either 850nm or 940nm, I have not
| looked into that aspect of it. I imagine that it's possible
| that your camera can detect one but not the other...
| ddingus wrote:
| My phone goes up to 980nm and it is a Note 9.
|
| Both front and rear cameras work.
|
| The light shows up as a pinkish purple.
| botanical76 wrote:
| Thanks, I had no idea about this.
|
| My Google Pixel 8a doesn't show anything on either
| camera, but my friend's front camera did! It shows up
| light purple.
| karlkloss wrote:
| Raspberry Pi sells a camera especially without IR filter.
| lightedman wrote:
| Easy test - check your black levels against someone wearing
| a black fabric or a reflective black surface. If you get a
| fair bit of grey in the image, odds are very great that you
| don't have an IR filter installed.
| runjake wrote:
| Lies. :-)
|
| Somewhere in my HN comment history from a while back is a
| response to a person claiming that modern phone cameras can't
| detect IR illumination and remotes.
|
| I took a bunch of modern iPhones and Android phones, from
| colleagues in an IT dept, and demonstrated they can in fact
| see a bunch of different IR remotes and illuminators with the
| rear camera.
|
| I could find zero cameras that could not see the IR.
|
| I'm not sure where people got the notion they couldn't.
| JKCalhoun wrote:
| Guessing because they read that CCD's have IR filters on
| them.
| runjake wrote:
| Update: here's the comment:
| https://news.ycombinator.com/item?id=40513967
| pwg wrote:
| The ultimate answer is "it depends". And upon what it
| depends is the particular IR wavelength the camera emits to
| "illuminate" a scene in IR for night photography.
|
| My cell phone's back camera will show IR light from IR
| remote controls (I've used it for just that to verify that
| a remote is transmitting). But I also have an outdoor IP
| camera with IR illumination in my back yard. The same cell
| phone camera sees zero IR emitted from the outdoor IP
| camera (even though it quite well lights up a fairly broad
| area of the yard at night).
|
| So for my phone, if a 'spy cam' were using the IR
| wavelength the IP camera uses, I would never know it was
| present by using the phone camera. If it used something
| closer to the wavelength used by IR remotes, yes, then the
| 'spy cam' would light up via the phone camera.
| lightedman wrote:
| "I'm not sure where people got the notion they couldn't."
|
| I make IR devices. My phone is the only one in the
| warehouse that can pick up their emissions - everyone
| else's cameras have IR filters with what appears to be a
| sharp ~750nm cutoff. I'm the only one that will pick up
| 800-1064nm with my cheap Samsung, and so I'm the only one
| doing the testing on those diode assemblies.
| alwayslikethis wrote:
| Most of the bright IR lights you find on typical surveillance
| cameras actually visibly look a little red. I wouldn't think
| the same lights would be used if the intention is to spy in
| secret.
| declan_roberts wrote:
| That's exactly right, and part of that is because they're
| cheap and put off some visible light.
|
| Thankfully the perverts who put this stuff in airbnbs just go
| to amazon and search and buy cheap stuff, which is easy to
| detect.
| kube-system wrote:
| The lower wavelengths like 850nm IR LEDs are visible. Some
| cameras use higher wavelengths like 940nm IR LEDs and they
| aren't.
| jmward01 wrote:
| In Japan there was a requirement to make a noise when taking a
| picture on a phone. I'm not a huge fan of that since there are a
| lot of reasonable reasons to not want noise, but I would be a fan
| if any capture device was require to advertise its presence
| wirelessly to make it easy for any smart device to notice an
| active recording device nearby. That wouldn't stop sophisticated
| surveillance but it would act like a cheap lock and stop a lot of
| the abusive stuff, or at least let people more quickly notice it.
| rahimnathwani wrote:
| > but I would be a fan if any capture device was require to
| advertise its presence wirelessly to make it easy for any smart
| device to notice an active recording device nearby
|
| That would be convenient for burglars or dishonest cops.
| sriram_malhar wrote:
| Dang. Never thought of that. No free lunch, eh?
| Cthulhu_ wrote:
| A burglar isn't deterred by a camera though. I mean for this
| use case they'd already be inside. Cameras don't prevent nor
| solve crime, at best they're for legal purposes if someone is
| caught, or for insurance claims.
| kube-system wrote:
| That sentiment has selection bias built in. Anyone who
| commits any crime wasn't deterred by everything.
|
| It is, however, factual that people choose to behave
| differently when they know they are being recorded. That
| might mean choosing not to commit a crime, commit it
| elsewhere, destroying a camera, or wearing a mask. While a
| functional camera can't prevent crime, it can identify
| those who commit them.
| RamboRogers wrote:
| This Device lights up pretty good on wireless or cellular data
| transfer. If my wife starts browsing on her phone it lights up.
| ddingus wrote:
| Of course nefarious actors will ignore the requirement and or
| hack their gear.
| bbarnett wrote:
| There is an upside though. An additional criminal charge, and
| making it easier to prove intent.
|
| (Note I said _easier_ , not just "prove", for it is indeed
| only easier.)
| rkagerer wrote:
| _" If you don't have a 9V battery, you can use a 9V battery."_
| RamboRogers wrote:
| lol, some bad summary there. It uses a lipo 3.7
| RamboRogers wrote:
| I fixed it, thanks for the comment :-)
| ujikoluk wrote:
| I have long dreamt about building a portable phased array for
| this purpose, but additionally using the phase difference between
| receivers to visualize where the transmission source is.
|
| In effect a camera into the RF world!
| transpute wrote:
| Could be combined with AR,
| https://hackaday.com/2019/01/09/smartphone-app-uses-ar-to-vi...
|
| DIY radio telescope tuned to 2.4Ghz WiFi,
| https://www.youtube.com/watch?v=g3LT_b6K0Mc
|
| Image of physical building overlaid with RF sources,
| https://www.facebook.com/thethoughtemporium/posts/2162600763...
|
| _> When I made the first video and photoshoped my impression
| of what I thought this would look like, I never imagined it
| would actually be this close. It 's official, our telescope can
| map the wifi in a building as if it were any other form of
| light._
| ujikoluk wrote:
| Oh neat! Yes that's the kind of imagine I want to see
| coin wrote:
| Title is misleading. It only detects RF. A hidden camera could
| record to storage for later upload in which case wouldn't be
| transmitting continuously.
| KeplerBoy wrote:
| Depends on the sensitivity of the device. It might be possible
| to pickup the EMF of the camera, even if it's not actively
| broadcasting.
|
| Every current carrying trace is an antenna.
| satori99 wrote:
| What you really need is a Non-Linear Junction Detector. These
| can detect an unshielded device with transistors, even if
| it's off.
|
| https://en.wikipedia.org/wiki/Nonlinear_junction_detector
| killingtime74 wrote:
| That would only be practically useful in an environment
| devoid of all other electronics. How would one tell between
| the non-transmitting spy cam and normal household electronics
| KeplerBoy wrote:
| By having some spatial/angular resolution. You'd need a
| large directional antenna or multiple antennas to have
| something similar to a phased array radar, but passively
| (i.e. listening only).
| RamboRogers wrote:
| It doesn't say "all", it also doesn't detect a someone in the
| closet, unless they're transmitting.
| consumerx wrote:
| it seems multiple ESP32s would fit into this giant case.
| RamboRogers wrote:
| You could without boost converter and the battery.
| https://x.com/rogerscissp/status/1847430193113141549/photo/1
| yftsui wrote:
| The most effective way would be use a Thermal Camera, because a
| normal "hidden camera" you get from eBay will consume around 5
| Watts - a significant heat dissipation.
|
| For others, probably just get an off the shelf TinySA?
| transpute wrote:
| _> TinySA_
|
| What's the frequency range and scanning speed of TinySA?
| garblegarble wrote:
| Another way to detect hidden cameras is optical augmentation,
| using reflections to locate lenses; this can detect cameras
| that aren't currently on / actively transmitting.
|
| Some paper and product references:
|
| - (PDF) http://s3.amazonaws.com/arena-
| attachments/1381379/c3a4e75132...
|
| - https://www.spycatcheronline.co.uk/product/camera-detector/
|
| - https://www.ijser.org/paper/Lens-Detection-System-using-
| Opti...
|
| - https://patents.google.com/patent/US20090237668A1/en
| Cthulhu_ wrote:
| That camera detector is pretty pricey; I once saw a low-tech
| solution that was basically a dyed card that you had to put
| in front of your phone camera with the light on, the light
| reflected by the camera lens would become very visible.
|
| Of course, only a matter of time - if they don't already
| exist - before there's cheap spy cameras without a reflecting
| lens, like a solid state camera of sorts. I believe some
| years ago they were experimenting with that as an alternative
| to a front facing camera on phones.
| RamboRogers wrote:
| TinySA looks cool! I want one.
|
| I made a thermal camera
| https://github.com/RamboRogers/M5StickCPlus2-AMG8833-Thermal...
| slow_typist wrote:
| OP, cool project. I have questions though:
|
| How does the device detect very short bursts? After looking up
| the data sheet of the RF detector I believe you would need
| additional circuitry to not risk that very short bursts slip
| through the sampling of the ESP A/D input.
|
| Second, the supply voltage of the detector seems to be 3.0 V to
| 5.5 V, https://www.analog.com/en/products/ad8317.html
| RamboRogers wrote:
| It doesn't detect short burst well at all. It does detect
| traffic over a second or so, like a TCP session of an h264
| stream.
|
| https://www.amazon.com/dp/B07FHZXTCZ?ref=ppx_yo2ov_dt_b_fed_...
|
| Specifications: Working frequency: 1M--10000MHz Measurement
| power: -55dBm to -0dbm Output voltage: 0.33- -1.65V Detection
| slope: -22mv/dBm (typical value) Input impedance: 50O Supply
| voltage: 7-15V Size: as the picture Weight:7g
| 9dev wrote:
| While researching for parts, I also found this one:
| https://www.amazon.com/dp/B07RR86PFC/ It goes up to 10GHz,
| and it operates on 5V. Would that also be an option, and
| possibly allow to get rid of the boost converter too?
| transpute wrote:
| 2018, _" Low budget consumer hardware espionage implant"_, 220
| comments, https://news.ycombinator.com/item?id=40363704 &
| https://news.ycombinator.com/item?id=20190251 &
| https://news.ycombinator.com/item?id=15676737
|
| 2019, _" Airbnb Has a Hidden-Camera Problem"_, 50 comments,
| https://news.ycombinator.com/item?id=24324300
|
| 2019, _" How to find hidden cameras in your AirBnB"_, 300
| comments, https://news.ycombinator.com/item?id=20457419
|
| 2023 repro of "Great Seal Bug" (1952): mechanical microphone, no
| power source, data exfiltrated via external directed microwave
| beam, https://www.youtube.com/watch?v=NLDpWrwijE8
|
| Try measuring the RF emissions of: USB hubs
| AC power strips SSD enclosures monitors
| goodpoint wrote:
| This is ineffective against most recording devices.
| RamboRogers wrote:
| Only if it's transmitting, this detects rf. It can't detect
| ears.
| goodpoint wrote:
| ...and only if the transmission is frequent enough.
| RamboRogers wrote:
| 100%, it needs to transmit pretty much constantly.
| Something like an H264 stream or an audio stream via TCP or
| UDP over something like wifi.
| amelius wrote:
| Does it get confused by nearby WiFi transmitters?
| RamboRogers wrote:
| It baselines on power on. So you'll need to get closer to raise
| the baseline. It also doesn't seem to alert on beaconing (or
| very little), my wifes phone and other devices need an active
| transfer to trigger it. (more than a 1/2 second)
| amelius wrote:
| Might also be useful for initial EMC compliance testing, maybe.
| beardyw wrote:
| Those 128x64 displays are easy to use, but frustratingly
| variable. They have differing start up sequences which using the
| wrong one leaves a blank screen.
| severino wrote:
| > They have differing start up sequences which using the wrong
| one leaves a blank screen.
|
| You mean, bricked?
| beardyw wrote:
| No, just no clue why it is unhappy.
| danbruc wrote:
| Fun fact, you can actually detect semiconductor devices even if
| they are powered off and hence emit no radiation unless the
| design took specific precautions. This works by illuminating a
| region with high frequency electromagnetic radiation and then
| listening for the effects that PN junctions have on the reflected
| radiation due to their nonlinearity. [1]
|
| [1] https://en.wikipedia.org/wiki/Nonlinear_junction_detector
| amelius wrote:
| > Thousands of diodes were mixed by the Soviets into the
| building's structural concrete, making detection and removal of
| the true listening devices by its American occupants nearly
| impossible.
|
| Wow ...
| mxuribe wrote:
| That's called playing the long game, and playing it quite
| cleverly!
| daveguy wrote:
| Not really. It makes it clear from the first attempted
| sweep they altered construction -- the opposite of a long
| game.
| krisoft wrote:
| That depends on what the game is. For example if they
| wanted the embassy to stay in their old already
| compromised premises they achieved that. (for about
| twenty years at least.) If they wanted the USA to spend a
| lot of money they also achieved that.
| hoistbypetard wrote:
| Yeah!
|
| It also makes me suspect that the device would not be super-
| useful in most environments today because our homes and
| offices have false positives littered all over the place.
| Such a countermeasure would be unnecessary now.
| diggan wrote:
| > useful in most environments today because our homes and
| offices have false positives littered all over the place
|
| Like the structural elements in your house/apartments have
| something similar to diodes in them, or what are you
| referring to?
| gorjusborg wrote:
| > our homes and offices have false positives littered all
| over the place
|
| Sure, but location matters. Searching weird (for
| electronics to be), but line-of-sight places (like a
| bookcase) you might still have a good signal to noise
| ratio.
| alwa wrote:
| I wonder if it would be feasible, with modern techniques and
| sufficient motivation, to map where the "background" diodes
| ended up setting in the concrete; then to measure newer
| sweeps against that baseline.
| danbruc wrote:
| Here [1] are some pictures and additional details on NLJDs. You
| can get your own, for example the Orion 2.4 [2] for USD 15.2k
| (free shipping) [3].
|
| [1] https://www.cryptomuseum.com/df/tscm.htm#nljd
|
| [2] https://reiusa.net/nljd/
|
| [3] https://spyassociates.com/orion-2-4-non-linear-junction-
| dete...
| stavros wrote:
| Oh good, I really wasn't prepared to pay the $7 for shipping
| that.
| AlanYx wrote:
| Are nonlinear junction detectors still state-of-the-art for
| detecting hidden devices when powered off? Does anyone know if
| alternatives like electronic noses (to detect chemical
| signatures associated with IC packaging) and magnetic anomaly
| detection increasingly used for this?
| thih9 wrote:
| Does anyone have a personal experience with finding a hidden
| camera in an AirBnB?
| lynx23 wrote:
| Well, not in an AirBnB, but... Already years ago, they found
| one in the ladies room at work...
| RamboRogers wrote:
| I found someone with a pen recording me. They left it on the
| desk, and I took it by mistake. I found it in my kit and
| realized it was a spy device.... yikes.
| binarymax wrote:
| Yes, but it was obvious and I didn't use equipment. It was in
| Jan 2020 at an Airbnb "hotel" in Nashville. There were two
| smoke detectors in the room. One of them was not like the
| other. I wrapped it in toilet paper. I left it wrapped so the
| owners knew that I knew, but I didn't bother reporting it
| because I rarely used Airbnb and it was a last minute trip. And
| then the pandemic hit and that was that.
| JKCalhoun wrote:
| > There were two smoke detectors in the room. One of them was
| not like the other.
|
| I imagine too that the other was not like the one. ;-)
| marsh_mellow wrote:
| Very cool! Could this work for detecting nearby drones?
| RamboRogers wrote:
| I would think it would work really well for that usage case.
| You could tune the antenna to focus on the in use bands. The
| automatic baselining solves a lot of this.
| sandworm101 wrote:
| >> It's useful to find hidden cameras, wiretapping devices, and
| other RF-enabled devices.
|
| Nope. It is used to find RF- _emitting_ devices, the sort of low-
| sophistication stuff you can buy online for real-time continuing
| surveillance. For many decades, the real spy stuff has operated
| in burst mode: collecting data quietly and only transmitting it
| at an agreed time or in response to an external signal. To detect
| them you need to be monitoring 24 /7 with a rig capable of
| triangulating signals that might only last a second or two.
| RamboRogers wrote:
| This finds a Wyze camera or many of Wifi Cameras as
| demonstrated in my video. So yes, with proof attached. Thanks
| 01100011 wrote:
| What I really want is something that detects any EMF above 60Hz.
|
| When I was a kid I used to hook a coil of wire and a diode to a
| piezo earphone. I then listened to the emissions of various
| devices in my house. My Amiga 500 was particularly interesting.
|
| I ran across a few projects that do the same thing but add an
| opamp and recording so you can generate sounds for electronic
| music.
| anthomtb wrote:
| > any EMF above 60Hz.
|
| Isn't that effectively all the EMF? You may be missing a
| prefix.
|
| Edit: huh, turns out these frequencies do have some
| applications: https://en.wikipedia.org/wiki/Super_low_frequency
| 01100011 wrote:
| Anything above 0Hz radiates. EMF is short for
| 'electromagnetic field' which even DC produces, so I guess I
| could have worded it better.
|
| In any case, I would want to detect the emissions from the
| CPU, memory bus and SD card traffic. Not all cameras are
| WiFi. Sure, that won't detect passive listening devices or
| other advanced techniques, but most people now are worried
| about video and that will have certain characteristic
| emissions.
|
| Edit: Something like CamRadar, presented here:
| https://dl.acm.org/doi/10.1145/3569505
| banku_brougham wrote:
| Can you give more detail so I can do this with my kid? I'm a
| not a hardware person but handy enough I think. How would I
| connect the diode to the coil? By coil do you just mean wound-
| up wire or is this an electronics component?
| jdthedisciple wrote:
| Genuinely curious: What do you expect to hear from your CPU or
| GPU?
| danparsonson wrote:
| Eeeeeeeeeeeeeeeeeeeeeeee!
| dmicah wrote:
| Check out: https://store.lom.audio/collections/elektrosluch-
| accessories
| bloopernova wrote:
| This is really cool! Have you considered using a Software Defined
| Radio or would that not improve capabilities enough to be worth
| the hassle?
| sriram_malhar wrote:
| Thanks for this useful project. Can I trouble you to add a
| circuit diagram of the latest rev? So much easier than reading
| text.
| omagramma wrote:
| This doesn't do anything useful. To detect RF transmissions you
| need to sweep a range of frequencies stopping at each frequency
| for a period of time for the Rx amp to sample. The AnalogDevices
| detector that is uses needs to be programmed, and the arduino
| code doesn't do that. It doesn't have the bandwidth or
| performance to do any real scanning. There's a reason why
| spectrum analyzers cost thousands (or tens of thousands) of
| dollars.
|
| Its funny watch Arduino (ease) programmers try to figure out RF
| (very hard).
| RamboRogers wrote:
| You know, when my wife opens up a webrowser on her phone and it
| starts transmitting this device triggers. When I go next to a
| wifi camera and it picks up the RF, it triggers.
|
| Demonstrably it does detect signals. You clearly don't
| understand the basics (very easy).
| jdthedisciple wrote:
| looks good, now I just need a version of the same software that
| runs on my phone so I don't need to buy all these materials and
| slap them together
| swayvil wrote:
| A thing for talking to rfids might do this. Some phones have an
| rfid thing. If it could sweep a frequency range.
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