
How to Find Hidden Cameras and Spy Gear - loteck
https://www.senteltechsecurity.com/blog/post/how-to-find-hidden-cameras/
======
weinzierl
Doesn't mention the good old _Nonlinear Junction Detector_. (NLJD) [1] or _The
Broom_ as they call it. It can find any unshielded device containing
semiconductors, no matter if the device is powered or not - which is pretty
cool. It is possible to build one yourself which is even cooler. Although I
have to say, while it is a WW II era device, DIY building is not a beginners
project. The British documentary _" The Spying Game - Walls Have Ears"_ has a
good interview with its inventor that even includes a demo of the device by
him in his wonderful old school lab[2].

[1]
[https://en.wikipedia.org/wiki/Nonlinear_junction_detector](https://en.wikipedia.org/wiki/Nonlinear_junction_detector)

[2]
[https://www.youtube.com/watch?v=4EWYI9zfF9Y#t=22m30s](https://www.youtube.com/watch?v=4EWYI9zfF9Y#t=22m30s)

~~~
consp
Can't a well build device mitigate this by just using up the energy provided
by the NLJD before it is re-transmitted by the semiconductors as a harmonic of
the original signal? As far as I my knowledge goes of these, it can detect the
created harmonics of the original signal.

~~~
londons_explore
Using up all the energy would require a perfect impedance match, which would
be very hard to achieve.

Even a 1 percent error would be easy to detect, since radio receivers can
easily have 100 dB of dynamic range, and decibels is a log scale, so that's
massive!

~~~
rkangel
The linked wikipedia page describes a countermeasure a little like that
described.

------
smarks
_One quick and cost-effective way to detect IR light is by using the front-
facing camera on your phone._

 _Unlike the rear-facing camera, the front-facing camera does not have an IR
filter and can easily pick up IR lights in the dark._

 _To try this at home, grab your TV remote, which uses IR light to send
information to your TV and open the front-facing camera on your phone. Next,
point the front end of the remote at the camera and press any of the remote
buttons. The IR light that is normally not visible will be completely visible
on your camera screen._

Well I’ll be darned. This works! (iPhone 7)

~~~
TeMPOraL
I don't remember seeing a _rear-facing_ camera for which it wouldn't work. Are
there extra IR filters installed on newest models, or is that an Apple thing?

~~~
tapland
I was also surprised. My old Galaxy S6 detected it fine (which is great when
DIY-ing a TrackIR). I have to go home, plug it in and see if newer phones are
any different.

~~~
TeMPOraL
My S7 handless this as well, and every Android phone I ever tried this on has
a rear camera receptive to IR (I usually test it on TV remotes).

------
andrewstuart
Here's a review of a hidden camera digital clock:
[https://www.youtube.com/watch?v=wMtG_fAL9aI](https://www.youtube.com/watch?v=wMtG_fAL9aI)

And someone using a FLIR infrared camera to find hidden cameras:
[https://www.youtube.com/watch?v=ndlhlBIG0SQ](https://www.youtube.com/watch?v=ndlhlBIG0SQ)

------
chrsstrm
I have a routine when entering a hotel room that involves scanning for devices
similar to what the article mentions (but not as far as using specialized
equipment). I'm not paranoid about being spied on, giving a proper once-over
makes me feel more at ease when inside the room. You never find anything,
which is always a relief, but a couple years ago when hotels started
installing smart mirrors it sure made my heart beat faster when you shut off
the bathroom light and look at the mirror with a light source. I've also
recently started seeing hall effect switches on hotel room doors. I'm not sure
how they are being used, but I usually pull the magnet out of the door and put
it on the mini bar and no one comes running thinking the door has been left
open. I'm not a fan of the hotel knowing when I come and go. I've seen a
motion sensor once but I believe those are more for the room's HVAC.

~~~
bdamm
Of course the hotel can track your face with lobby cameras, your room key when
you authenticate with the elevator and door, and monitor your use of the Wi-
Fi, so really they don't need a camera or hall effect sensor to know you are
coming and going or get some idea of your preferences.

~~~
chrsstrm
I would be genuinely surprised if hotels implemented facial recognition. I'm
the one who doesn't touch hotel WiFi - cell tethering to the rescue. And yes,
all these hotels use NFC keycards, which makes the placement of door sensors
even more puzzling. You can't be invisible in a hotel but there is a level of
knowledge on your whereabouts that they just don't need. Sadly the Las Vegas
incident isn't helping as management is more paranoid than ever of a repeat.

~~~
9h12dqe
They are already doing so. VIP recognition and check-in are two cases.

------
vertexFarm
I'm interested that it doesn't mention the nonlinear junction detector, but
I'm no spyhunter or anything and maybe that's an obsolete piece of equipment
now. After all, there's certainly a lot more innocent transistors and diodes
out in the world today than there were during the cold war. Also I'm not sure
they're legal for just anybody to use since they vomit so much radio
interference.

An interesting build:

[http://67.225.133.110/~gbpprorg/mil/non/index.html](http://67.225.133.110/~gbpprorg/mil/non/index.html)

~~~
weerd
Woah! The electronics info at this site seems interesting... but stuff gets
pretty wild...

[http://67.225.133.110/~gbpprorg/obama/](http://67.225.133.110/~gbpprorg/obama/)

~~~
microdrum
Did these 67.x links above kill anyone’s device cellular connection? Something
dangerous going on there.

~~~
justtopost
No, that seems more improbable than the linked ramblings.

------
ouid
this article is actually just an advertisement for this product.
[https://www.senteltechsecurity.com/lawmate-
dd802-defender.ht...](https://www.senteltechsecurity.com/lawmate-
dd802-defender.html)

~~~
gk1
This is such a cynical statement that I'm tired of seeing on HN.

Yes, the article mentions a product from the company, not in a sneaky way. The
rest of it, some 2,800 words, is interesting and informative--to me, at least.

An article can be both informative and self-serving, and there's nothing wrong
with that, provided there's no deception. Most of what you read online is
self-serving, in some way.

~~~
ouid
>provided there's no deception.

First of all, your caveat does not hold. This article is deceptive in full.
None of the advice presented here is good at all... "divide the room into
quadrants and search each quadrant"? Why? Just search the entire room. The
article fundamentally gives the impression that you will not actually be able
to locate any spygear unless you have an RF detector and a camera beacon
simply by not giving any good advice otherwise. "Check if the outlet covers
have been changed?" right, because when I bug a house that I own, I also buy a
new outlet cover.

No one trying to sell you something is going to tell you how you could
effectively live your life without their product. This is fundamentally
deceptive, and seems to have gone so far as to have fooled even you.

~~~
booleandilemma
_None of the advice presented here is good at all... "divide the room into
quadrants and search each quadrant"? Why?_

The article answers that:

 _Splitting the room into sections will help you to systematically and
meticulously go through the room and clear each section without skipping over
any of the fine details._

This strategy is generally known as “divide and conquer”.

~~~
ouid
no, the strategy of divide and conquer exclusively refers to situations in
which the whole is greater than the sum of the parts, in this case they are
exactly equal.

In military parlance, it means that you have a much greater advantage against
2 armies of half size separately than against them both simultaneously. This
is known as Lanchester's law, and the whole point is that it's non-linear.

In algorithms, the idea is roughly that, given a method which solves a
problem, it is often cheaper to split your input, solve each half, then merge
them, than it is to run the algorithm on the entire input. Again, non-linear.

Dividing your room into quadrants provides NO advantage to searching your
room. You still have to search each unit area methodically.

~~~
pergadad
The suggestion is not about efficiency, it's about not forgetting anything.

~~~
ouid
I'm pretty sure most people have a pretty intuitive understanding of how to
perform a methodical search of a room. The article promises clever tricks for
finding bugs and cameras in a room without having to spend any money, and
fails to deliver on that premise, deceptively, because it is solely an
advertisement for a device that is FAR more expensive than it needs to be.

~~~
mrob
>I'm pretty sure most people have a pretty intuitive understanding of how to
perform a methodical search of a room

And surgeons were pretty sure they'd never leave an implement inside a
patient, but the stats still improved with the introduction of checklists.
Like checklists, the quadrant method means there's less demand on your memory,
which means less chance of forgetting things if something unexpected happens.

~~~
TeMPOraL
Thus, the article would be _much_ better if it provided a checklist with
concrete, actionable steps instead.

This is a difference between content marketing and actually caring about
informing the reader.

~~~
logfromblammo
The checklist can also be ordered such that the lowest-hanging fruit is
covered first. Start with the vent covers, overhead lights, and smoke
detectors, because those are the places where it's easiest for an unskilled
spy to hide monitoring devices. Any hole cut into the sheetrock for a legit
purpose could also have a peephole near it.

I bought a house that had a slight dimple in the heating duct of a ground-
level bathroom, mostly concealed by the vent cover. I went down into the
basement, and surely enough, from a certain spot, I had a clear view of the
toilet and shower from below. I bent the duct back flush with the edge of the
hole, and concluded that was probably one of the reasons that the sellers were
getting divorced. So you might not find a camera. There might be an actual
eyeball there sometimes. An electronic scanner isn't going to find that.

------
loteck
Google cache:
[https://webcache.googleusercontent.com/search?q=cache:rZMVkY...](https://webcache.googleusercontent.com/search?q=cache:rZMVkYxBElIJ:https://www.senteltechsecurity.com/blog/post/how-
to-find-hidden-cameras/+&cd=1&hl=en&ct=clnk&gl=us)

------
aldamiz
"The best way to check for a two-way mirror is by using your fingertip. On
most mirrors, if you place your fingertip on the mirror, the reflection of it
will not touch. Instead, it will leave a quarter inch gap or so"

Went to check all mirrors at home, and placed my fingertip on them. In all,
the reflection of my finger touches my finger.

I'm gonna need to have a serious conversation with my wife now.

~~~
vldx
I’ve done the same and had the exact same experience. What is the reason for
that?

~~~
borgel
I assume it has to do with which side the reflective coating is on? If it's on
the room-facing face there is no gap. If it's on the backing (wall-side face)
there is a gap as thick as the glass.

~~~
sm4rk0
The reflective coating (silver or alumin(i)um) of a glass mirror is usually on
its back.

Gap should be _twice_ the glass thickness because the light travels the
distance twice.

------
andrewstuart
Is unplugging the power of the router in an AirBNB a good basic security step?

Presumably some cameras depend on flash storage rather than Internet
connection but many cameras do use Internet connection to function?

~~~
acct1771
I just cut the power to the house when I arrive.

~~~
ackfoo
"Today engineers will succeed in restoring water and power to your area,
leaving you with hours of hard sledgehammer work to get it back the way you
like it." \--The Onion

------
cyborgx7
Why does a completely static blogpost have a loading animation? Some really
bad engineering decisions have been made here.

~~~
frankzinger
If only there were readily-available tools to find hidden website bloat. /s
(directed at them, not you)

9,70 MB / 7,93 MB transferred; many 100+ and 500+KB images, two over 1MB; one
800KB (minimised!) stylesheet.

Pretty crazy. Took over 1 minute to load on my 2Mb/s connection.

------
tzhenghao
You could also roll your own (at your own risk) :) [1]

[1] -
[https://github.com/JulianOliver/dropkick.sh](https://github.com/JulianOliver/dropkick.sh)

~~~
aboutruby
Would be nice as an app or a portable device like a button (kind of like the
universal remote to shutdown TVs[1]).

[1]: [https://www.amazon.com/TV-B-Gone-Universal-TV-Control-
Keycha...](https://www.amazon.com/TV-B-Gone-Universal-TV-Control-
Keychain/dp/B0006GD9CE)

~~~
AJMaxwell
Wouldn't be too difficult to run it on a Raspberry Pi

------
heyjudy
This is a real problem for females in Korea, where spy cameras are a real
thing. So much so, there's a Korean word for, it "molka," and a Kickstarter
for a handheld device that can find even pinhole cameras based on reflected
visible light from an array of LEDs.

[https://www.kickstarter.com/projects/spyassociates/spyfinder...](https://www.kickstarter.com/projects/spyassociates/spyfinder-
pro-hidden-camera-detector-spying-preven)

------
_underfl0w_
This is an excellent follow-up to the AirBNB story posted here earlier.

Tl;dr AirBNB ruled that a host's photo with an easily-glanced-over single
camera tucked in a corner was sufficient evidence and documentation of the
fact that they had multiple cameras inside - i.e. that the guest should've
been aware that there was no expectation of privacy. The article mentioned
unplugging said equipment, other comments mentioned guests having found
cameras in alarm clocks in AirBnBs, etc.

~~~
gcbw2
Typical airBNB customer care.

How is it they recommend unplugging the cameras, if they say seeing one camera
is the same as acknowledging there are other hidden ones?

How do you unplug that which you cannot see?!

------
deytempo
If it’s an IP camera, you can solve the problem by carrying a little switch
and patch cable. The switch plugged into an Ethernet port, then the jumper
cable plugged across two of the ports in the switch. If the camera is on the
same network no appreciable amount of data will be getting from that camera
back to where it is supposed to be recording

~~~
go_prodev
Why is that? Wouldn't it just double the data volume, or does it do something
else?

~~~
TeMPOraL
It'll make the switch gum the network up with broadcast and multicast packets
forever looping around the switch.

Back in my high school days, looping two Ethernet ports with a patchcord was a
trick you could use to take down the entire school network. I was under
impression that modern hardware has safeguards against that, though.

~~~
citrin_ru
This safeguard is called STP (spanning tree protocol). I've seen it only in
managed swithes and most SOHO swithes are unmanaged. It is easy to detect
usage of STP using tcpdump.

------
harshulpandav
There's also a research paper on this subject. Some of the information in it
might no longer be relevant in today's world though.

[http://www.tentacle.franken.de/papers/hiddencams.pdf](http://www.tentacle.franken.de/papers/hiddencams.pdf)

------
Havoc
So spend 250+ and carry all that extra gear with me while traveling to hotels?

I could see this being a thing in Airbnb though unfortunately.

~~~
jarfil
You can get an RF scanner with a laser lens scanner for $10, and your phone
camera is good enough for detecting IR LEDs. The only expensive part is the
FLIR camera, but still 3 out of 4 for $10 is not bad.

~~~
remcob
FLIR Camera has many good uses. I bet in a hot or cold climate you can quickly
win it back in heating/cooling costs by optimizing insulation.

------
SudoEpoch
Cameras are easy to find. You use red glasses (laser safety ppe) and a red
light source. The type of polymer they coat lenses in is highly reflective in
the red spectrum. With out getting into too many details you just shine the
light around looking for strong pin pricks of red light. I've got experience
doing this for over 20 years and this is by far the most effective approach
100% of the time.

------
elchief
It's funny how in spy movies a sniper or observer has a big ol lens pointed at
a target.

Govt buildings have lens detectors.

And I'd hope high value targets teams do too

~~~
matt-attack
> Govt buildings have lens detectors.

Care to explain? If I point a camera at my local Fed building while walking on
the nearby sidewalk, are you telling me that's detected somewhere?

~~~
rococode
Not a technical explanation but a story about a similar thing:

[https://www.wired.com/2009/09/russian-billionaire-
installs-a...](https://www.wired.com/2009/09/russian-billionaire-installs-
anti-photo-shield-on-giant-yacht/)

I remember this article as the first time I learned that photo-taking can
actually be detected. Given that it was written in 2009, I imagine that the
general camera-detecting technology has been mostly figured out by now.

~~~
Antonio123123
So when it detects a lens, it shoots light to destroy the photo.

If the detection is not ideal, it could detect eyeglasses and shoot light into
people's eyes

------
crankylinuxuser
I've proposed a talk at CircleCityCon that includes this area... except the
software stack I'm using makes sounds and then rapidly watches a large swath
of spectrum to find FM bugs.

I can also pick up 802.11* bugs too with standard wireless hacking toolset
that we're all familiar with.

I can't pick up video with it (5.8GHz FPV modules), but that shouldn't be too
hard to add at a later date.

I also can't pick up "record to SD" style of bugs. There's nothing to pick up
radio widse, and their tempest emissions are too miniscule to detect.

------
manishsharan
Didnt Hilton pay large sum of money to an ESPN reporter to settle a voyeur cam
issue ? This is why I choose Hilton -- they know spying on me or enabling
spying on me is going to be expensive for them.

For people using AirBnB -- the best you can hope for is your pictures don't
end up on a fetish site.

------
pohl
Bookmarking this for when we need to sweep the white house in a couple years.

------
dakpan
Why does he have 2 clocks, a bed, a toilet and a bathtub in the same room?

------
Giorgi
Camera inside alarm clock will pass all these tests.

------
crb002
Curious why they aren't using public key encryption when writing to the SD
card if they went to that much trouble hiding it.

~~~
cf141q5325
Power consumption I would assume

------
ffvhhbbgfcgbhf
As a pervert/voyeur I can recommend these tips for spotting 19 out of 20 such
pervs. The thermal being most effective.

------
navinsylvester
You can do basic detection via mobile app itself and they are surprisingly
good. I know they can't replace dedicated gadgets but for most it should be
enough and convenient.

On android i use Ultimate EMF Detector PRO and Hidden Camera(PRO version).
These should help you to detect electro magnetic field emanating from devices
and infrared camera. Be very careful while selecting the app since there are
lot of similar apps in the market from shady looking companies.

~~~
bogle
Who are the developers of those two apps? In the app store that's the
distinguishing feature between the Hidden Camera apps at least.

------
kingofhdds
My hidden bullshit detector says it's an advertising article playing on fears,
and having fake comments below it.

------
pcdoodle
This ia paranoid as hell. If you really needed to worry about it, you wouldn't
be reading this article.

~~~
tchaffee
It's not that paranoid if you use AirBnB a lot. I have caught one owner spying
on me with video, and so have some of my friends who use AirBnB as much as I
do. It's easy for the owner to mentally justify the invasion of privacy with
the excuse of protecting their property. When it happened to me I was on my
way to a friend's wedding so I didn't want to get the police involved, but in
hindsight I wish I had.

------
Pigo
I guess I'm lucky that I'm not important enough for anyone to bug me, besides
taking amazing video of me going at it with my hot wife going at it in a
hotel. Now that I think about it, someone would hit the jackpot if they got us
on film.

------
inteligencenet
using IR devices or buy RF detector from amazon to avoid hidden camera

------
paradoxparalax
Also, as any pretty girl in a DongGuan city's Sauna will teach you, put all
portable objects inside the room's wardrobe and cover everything you can,
including mirrors, with towels, bedsheets, or whatever piece of cloth you can
find. Put all flasks of Shampoo or body soap in the wardrobe aswell. Scan the
long curtains of the room's window with your eyes and hands. They are really
professionals there.

~~~
weinzierl
Why DongGuan? Wouldn't this be good advice anywhere around the world? Or is
this some kind of in-joke I don't get?

~~~
yakshaving_jgt
First result on Google.

[http://www.atimes.com/article/fall-liang-yaohui-king-
donggua...](http://www.atimes.com/article/fall-liang-yaohui-king-dongguans-
infamous-saunas/)

~~~
weinzierl
Your Google is not my Google apparently.

~~~
tlavoie
The filter bubble is real.

------
ILBCNU
Has anyone considered these pieces of equipment?

[http://aitproducts.com/products/fiberscopes/micro-
fiberscope...](http://aitproducts.com/products/fiberscopes/micro-
fiberscope/fiber-scope-milliscope.html)

They are very hard to spot. you have to inspect the area of concern for tack
holes or raised features in the wallpaper. As far as price is concerned, there
is a fair bit of profit that will be realized short term from the disgusting
type of porn that could be generated. Im sure there is some gaurded position
regarding sales of these devices, if not there should be.

~~~
owenversteeg
Depth of field is measured in millimeters for everything they list. I wonder
if that's a requirement of the hardware or something that can be overcome.

