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Posted by RamboRogers 10/24/2024

Show HN: RF Hunter – Find hidden cameras and other devices(github.com)
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.
594 points | 175 commentspage 2
kubectl_h 10/24/2024|
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 10/24/2024||
Don’t many of those just store data locally?
potato3732842 10/24/2024|||
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.
05 10/25/2024||
Not really, those are using PIR motion sensors to wake up, so you'd need to be able to capture the burst of activity when the camera actually wakes up and takes a picture. PIR circuit is very low power, so not much RF energy to detect while it's sleeping..
potato3732842 10/25/2024||
The unshielded electronics are still going to be highly RF reflective the same way that a car headlight is still reflective when not powered. Pretty much all bug sweeping works on this premise.

Finding a game cam in the woods with basic bug sweeping equipment is like finding a headlight housing on the ground in the woods at night using a flashlight.

05 10/25/2024||
> highly RF reflective

What do you mean, exactly? Most of what you can find in the forest is 'RF reflective' because of the water contents - the trees, the grass, the ground. What's the proposed detection method that is going to discern a reflection from a small PCB from a reflection from a large tree trunk?

edit: first, the camera isn't a retroreflector so you can't just light it up from any direction and get a strong reflection. Second, the kind of equipment that would give you good directionality with a static target is some next generation beam steering radar, that stuff is so expensive you're better off walking around with a 4K camera and then processing the footage with an image detector to find possible matches with images of trail cameras.

kubectl_h 10/24/2024||||
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 10/24/2024||
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 10/24/2024|||
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 10/24/2024|||
Game cameras are truly pathetic.
defrost 10/24/2024|||
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 10/24/2024||
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 10/24/2024||
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 10/24/2024|||
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 10/24/2024||
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?

toss1 10/24/2024|||
Or maybe, instead of relying on yet another toy of modern technology, do it the same way it was done before game cameras?

Learn the craft so that you can tell from the signs, such as tracks, droppings, markings, etc., and spend the time doing actual scouting and sightings before hunting?

Seems to me you're either enjoying the whole process of learning and doing the sport, or just enjoying the results. If the former, do it for real, if the latter, just buy some game meat from someone who does. Doing everything with excess technology and little craft seems more like cosplaying and just cheating yourself of a real experience.

toss1 10/25/2024||
and on your other 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?

I'd look at Glassdoor as reading the actual signs in the wild, like reading tracks, markings, broken twigs, etc., not an artificial aid — it's one of the signs in the environment. And like signs in the environment, it's not like a camera, it is often obscured, gamed, and skewed. Similarly, a crafty employee would also contact people she knows and exploit connections to scout the potential employer.

However, putting game cameras, webcams, and/or recording devices in their management offices, HR offices, and meeting rooms would be considered a bit out of bounds, you think?

kubectl_h 10/24/2024|||
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.

Loggias 10/24/2024|||
[dead]
RamboRogers 10/24/2024||
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.
omagramma 10/24/2024||
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).

CamperBob2 10/27/2024||
Parent post falls firmly into the "Not even wrong" category, after you get past the "Just plain wrong" parts (such as the need to program the AD8317.)
RamboRogers 10/24/2024||
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).

jmward01 10/24/2024||
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.
ddingus 10/24/2024||
Of course nefarious actors will ignore the requirement and or hack their gear.
b112 10/24/2024||
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.)

rahimnathwani 10/24/2024|||
> 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.

Cthulhu_ 10/24/2024|||
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 10/24/2024|||
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.

ted_dunning 10/25/2024|||
Actually, there is a rise of burglars going in with Wifi jammers to stop cameras.

So, yeah, I would think that is evidence that they care about cameras.

https://www.nj.com/morris/2024/06/burglars-are-using-wi-fi-j...

sriram_malhar 10/24/2024|||
Dang. Never thought of that. No free lunch, eh?
RamboRogers 10/24/2024||
This Device lights up pretty good on wireless or cellular data transfer. If my wife starts browsing on her phone it lights up.
slow_typist 10/24/2024||
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 10/24/2024|
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: 50Ω Supply voltage: 7-15V Size: as the picture Weight:7g

9dev 10/24/2024|||
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?
RamboRogers 10/26/2024||
Looks cool! make one :-)
slow_typist 10/25/2024|||
Thanks OP. The detector itself has a Pulse response time of 6 ns/10 ns (fall/rise) but of course the whole system will always be slower. 1 s is a lot though, got probably nothing to do with the sampling done by the esp.
sandworm101 10/24/2024||
>> 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 10/24/2024|
This finds a Wyze camera or many of Wifi Cameras as demonstrated in my video. So yes, with proof attached. Thanks
ajsnigrutin 10/25/2024||
Following the amazon links in the cpp brought me to this: https://www.amazon.com/gp/product/B07FHZXTCZ

Holy fsck, the build quality must be shitty if even the amazon photo looks horrible (just look at the area around the voltage regulator)

sriram_malhar 10/24/2024||
Thanks for this useful project. Can I trouble you to add a circuit diagram of the latest rev? So much easier than reading text.
o1o1o1 10/24/2024||
Interesting, thank you for sharing!

Maybe somebody knows: Is there something similar for the Flipper Zero?

RamboRogers 10/24/2024|
I could make it I suppose.
x______________ 10/24/2024||
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 10/24/2024||
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.

o1o1o1 10/25/2024||
First of all, I also would be very grateful if you can make this happen. I don't have too much free time currently and also no skill in hardware, but if there is anything else I can help with, I'd be happy!

Why do you find it cumbersome to use?

Terr_ 10/24/2024||
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 10/24/2024|
It runs the screen and reads the sensors, you can see it in the code.
ffujdefvjg 10/24/2024|
Cool project! I'd buy one of these if they were pre-assembled.
RamboRogers 10/24/2024|
Thanks, it costs about 30$ in parts. Not sure what a fair price would be.
tomcam 10/24/2024|||
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.

Eisenstein 10/24/2024|||
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?
tomcam 10/25/2024||
The custom PC components are already finished goods by the time they get to your PC assembly person. Most of the markup is already baked in. I would in fact expect to pay $120 or so to have a PC assembled for me, so we still get to the $150 figure in either scenario. I assume you have never worked for, or originated, any such business. That $150 has to cover overhead like assembly labor, rent, credit card charges, insurance, accounting, bookkeeping, excise tax, chargebacks and refunds, advertising, website development and social media, bookkeeping, software subscriptions, fulfillment, compliance, and so on. Running any business in the western world is complicated and expensive these days.

If you’re imagining you can take $30 worth of parts, sell the finished item for $60 or $90, and sustain that enterprise, it’s time to reconsider your business acumen.

ted_dunning 10/25/2024|||
There's a lot of ways to rephrase this to be less insulting.

For instance,

"lots of people have started with the idea that they could sell at retail for only 3-4x parts cost and failed"

or

"I have had personal experience trying (and failing) to drive down retail cost of electronics below this rule of thumb"

This last has the advantage of making the advice more personal.

tomcam 10/26/2024||
> "I have had personal experience trying (and failing) to drive down retail cost of electronics below this rule of thumb"

Didn't have to make such a statement because I paid attention to people who knew what they were doing. If someone had been this "insulting" with my attempt to beat Craigslist, OTOH, I'd have saved $1.4 million of my own money. I'm happy to be "insulted" by people with more experience.

Eisenstein 10/28/2024||
Or you can just admit that you don't care about other people's feelings.
tomcam 10/29/2024||
You have an active imagination. I like that in a budding social critic of your skill level!
Eisenstein 10/29/2024||
Since you are asserting that you do care about how you impact others, I would like to point that you have acted contrary to that assertion in our conversation. In particular, your:

* use of dismissive sarcasm ("active imagination") to deflect legitimate concerns

* deliberate infantilizing tone ("budding social critic of your skill level")

* preemptive dismissal of differing viewpoints ("This comment will be downvoted but only by people who...")

* assumption of others' inexperience ("I assume you have never worked for...")

* defensive response claiming that you have the right to be insulting to others ("I'm happy to be "insulted" by people with more experience.")

If you honestly do care about how you come across in your communications and have a desire to use your interactions with others productively and not in a way which comes across as bullying, I am happy to work with you privately towards this goal. Is this something you would be interested in?

tomcam 10/29/2024||
Thanks kindly, but my dance card is full.
ffujdefvjg 10/24/2024||||
That...doesn't sound unreasonable.
RamboRogers 10/24/2024|||
Thanks for the info, super useful.
ffujdefvjg 10/24/2024|||
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_ 10/24/2024||
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 10/24/2024|||
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 10/24/2024|||
This is a great idea.
b112 10/24/2024|||
It's sad we're letting bedbugs return.
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