How detect if MP3 player is recording in your room? [OT]

[kony]

You know how an IC gives off heat in relation to how
hard it is working, ("constant current" is a myth) heat is
only one part of the electromagnetic spectrum.

No, constant current is a fact. The IC draws constant
current in many MP3 players and does not substantially
change it's heat output unless entirely turned off or put to
sleep which is an entirely separate mode of player
operation, not momentary in use like with a CPU.

Switching
devices certainly produce as much "noise" when they
operate as analog devices, more in most cases.

We may have a mic on shielded cable running to a constant
current chip that digitizes. It's spitting out digits when
there's no noise as well as when there is. Yes there may be
noise, but it may not vary as with the old analog, and
certainly not as noisey as something more obvious- a
transmitter signal.

We have
devices that can detect very, very low wattage signals.

That may be useful if you have an object in your hand, but
remember the unknown context of this thread, and that they
can't be constantly false detecting cell phones, beepers,
etc, providing the cell phone isn't recording off-grid which
is a whole 'nuther issue.

 

[Matthew Hicks]

No, constant current is a fact. The IC draws constant
current in many MP3 players and does not substantially
change it's heat output unless entirely turned off or put to
sleep which is an entirely separate mode of player
operation, not momentary in use like with a CPU.

No, contsant current isn't a fact. When an IC sends outputs the signals on
the traces are switching and unless the same data is flowing you will see
different currents depending on what data is bieng sent and what was sent
before. Resistance can also change.


---Matthew Hicks

 

[Ken Maltby]

No, constant current is a fact. The IC draws constant
current in many MP3 players and does not substantially
change it's heat output unless entirely turned off or put to
sleep which is an entirely separate mode of player
operation, not momentary in use like with a CPU.



We may have a mic on shielded cable running to a constant
current chip that digitizes. It's spitting out digits when
there's no noise as well as when there is. Yes there may be
noise, but it may not vary as with the old analog, and
certainly not as noisey as something more obvious- a
transmitter signal.


That may be useful if you have an object in your hand, but
remember the unknown context of this thread, and that they
can't be constantly false detecting cell phones, beepers,
etc, providing the cell phone isn't recording off-grid which
is a whole 'nuther issue.

Normally people entering rooms have to pass through
doorways. I would think any "open mike" that responds to
the pattern should be considered a threat.

But look, you can believe what you want, your world can
be a much simpler place, if you don't delve into these issues.

Luck;
Ken

 

[kony]

No, contsant current isn't a fact. When an IC sends outputs the signals on
the traces are switching and unless the same data is flowing you will see
different currents depending on what data is bieng sent and what was sent
before. Resistance can also change.

The signals are fairly constant, encoded bits regardless of
whether there's silence or not. My argument is not whether
the mere presences of signals can be deteced, but rather
there is a significant enough difference in signal to detect
with sound input versus silence (in the room).

Claiming you will see different currents based on the data
is easy with the gear open and measurement by wire. Trying
to find whether there is an unknown device present or not is
not quite same situation.

 

[kony]

Normally people entering rooms have to pass through
doorways. I would think any "open mike" that responds to
the pattern should be considered a threat.

Sure, but we haven't established that it really will be
detectable based on a pattern of sound. Presuming it will
because some other type of device can be detected isn't
reliable.

But look, you can believe what you want, your world can
be a much simpler place, if you don't delve into these issues.

This is a fairly generic non-applicable comment. We could
as easily consider the opposite, that you can believe what
you want and your world can be a much more paranoid place if
you don't delve into the specifics- but either way we cannot
assume detection without any evidence of same type device
BEING detected in an applicable scenario. While a doorway
detector could be more easily implemented than some, it's
also not going to detect a device turned off at the time.

We'll have to consider the specifics of a digital recorder,
and perhaps even more significantly one that might be chosen
to be harder to detect if it were to be used for a stealthy
purpose.

 

[Jamie]

That sounds like BS to me. Of course cellphones are very easy to
detect that way, and I expect that is what he is showing off. Forget
about non-woreless devices. They have several orders of magnitude
less RF emanations. This guy is likely demonstrating with
cellphones and then claiming he can detect the other things
without ever demonstrating.

Arno

maybe you should step out of the dark and into the real world.
have you ever use a service monitor to scan a wide spectrum of
frequencies?
i can tell you that wide band receivers on a mini board exist and
are very sensitive to external R.F. when your standing beside the person
with in 3 feet of them.
most devices these day's involve embedded processes which also uses
R.F. clock devices. it would take a very high priced unit with proper
casing and shielding to reduce the emissions low enough for this device
to not detect it. most consumer electronics is very sloppy in the area.
in fact, there has been cases where cheaply made devices that xfer lets
say audio information in a digital format causes their internal osc's to
be unstable enough when voice is passing through the mic/pre'amp
circuits, that some one with a high gain FM receiver can detect clear
enough audio from a distance before it even gets encoded digitally for
final destination.
the average joe wouldn't even think of this let alone attempt to
waste their time in trying it how ever, there are people out there that
spend a lot of time investigating consumer devices just for the purpose
of simple wireless taps and detection of use.

 

[Arno Wagner]

Arno Wagner wrote:
maybe you should step out of the dark and into the real world.
have you ever use a service monitor to scan a wide spectrum of
frequencies?

I have used a spectrum analyser. I admit I am not an EMI expert.
However cellphone detection is far simpler than detection of other
devices....

i can tell you that wide band receivers on a mini board exist and
are very sensitive to external R.F. when your standing beside the person
with in 3 feet of them.
most devices these day's involve embedded processes which also uses
R.F. clock devices. it would take a very high priced unit with proper
casing and shielding to reduce the emissions low enough for this device
to not detect it. most consumer electronics is very sloppy in the area.
in fact, there has been cases where cheaply made devices that xfer lets
say audio information in a digital format causes their internal osc's to
be unstable enough when voice is passing through the mic/pre'amp
circuits, that some one with a high gain FM receiver can detect clear
enough audio from a distance before it even gets encoded digitally for
final destination.
the average joe wouldn't even think of this let alone attempt to
waste their time in trying it how ever, there are people out there that
spend a lot of time investigating consumer devices just for the purpose
of simple wireless taps and detection of use.

Oh, I know. But I was pointing out that the guy described does not need
to have what he claimed. And in addition, how do you separate, e.g., the
crystal in a high-powerd pocket calculator from the one in the MP3
recorder? Detecting RF energy is not that difficult. It becomes
difficult if you have a lot of background noise or need an identification
in addition.

Arno

 

[Joey]

I hinted at that a couple of days ago.
It has been amusing watching some of the replies from some of the
people here.

You man there actually is something which will detect MP3 recorders?

 

[Joey]

[...]

Sorry for my rather unhelpful reply, I'm having one of my moments
where I only talk to microcontrollers.

No problems.

Seriously though. There's very little in world that's so
important. I've worked with people that would *record* meetings
thinking they were of vital importance when in actual truth, no one
could care less.

I guess it would just cause people to be more careful about what
they say. I'm unable to view those videos you've supplied as this
is a development machine without any clutter on it.

eBay could be a good place to buy such things though. All sorts of
stuff comes out of the AsiaPac.

This is to document something quite serious.

 

[Dana]

You man there actually is something which will detect MP3 recorders?

There are devices that can detect when electronic devices are being used.
There are devices that can be made that can detect almost any known material
If said mp3 player is made of that material it can be detected.

 

[kony]

There are devices that can detect when electronic devices are being used.
There are devices that can be made that can detect almost any known material
If said mp3 player is made of that material it can be detected.

Which is not entirely applicable, since plenty of
non-recorders are made of circuit boards, ICs & other
discretes, and some plastic. Cell phone and pager are two
quite common ones.

Detecting electronics devices in general, is it useful? We
dont know the exact scenario, what the result would be of a
positive detection but as above, cell phones and pagers
would tend to be caught and are going to be far more common
and innocuous than a recording device, though in the former
case, the phone may have recording capability too.

 

[Dana]

Which is not entirely applicable,

Sure it is

since plenty of
non-recorders are made of circuit boards, ICs & other
discretes, and some plastic. Cell phone and pager are two
quite common ones.

Yep, and all are detectable, and all have signatures.

Detecting electronics devices in general, is it useful?

Depends on who you ask
The OP is not the only one who wants to ensure no one is able to record
conversations, or hear conversations they should not be hearing.

We
dont know the exact scenario,

He gave the scenario.

what the result would be of a
positive detection but as above, cell phones and pagers
would tend to be caught and are going to be far more common
and innocuous than a recording device, though in the former
case, the phone may have recording capability too.

True enough, but the technology is there to do what is being requested. Now
if the OP can afford it, or even obtain it is a different issue.

 

[max]

Would an all nude work environment be acceptable? It would make hiding such
devices difficult so you wouldn't have to do anything untoward like
searching people.

You'd be surprised where people can hide things:

http://www.dailymotion.com/blog/vid...3&play=1&referer=http://susiebright.blogs.com

Caution! NSFW!

max

 

[Dana]

Which is not entirely applicable, since plenty of
non-recorders are made of circuit boards, ICs & other
discretes, and some plastic. Cell phone and pager are two
quite common ones.

And what is a common item to circuit boards, IC's, cell phones, pagers, MP3
players, etc.
There are devices made to detect the presence of semiconductors, and these
have been out for ages.
And now with the war on terror going on, you would not believe what kind of
sensors they are coming up with.
Minor modifications of some of these units would not be very difficult to
detect a mere MP3 in someones pocket.
But then these would not be cheap either, if you can even get one.

 

[Alexander Grigoriev]

Well shielded (for example, wrapped to copper foil), 1.5V AAA powered device
will give EMI below ambient level. If its clock generator employs spread
spectrum, it's even more difficult to detect.

 

[paulmd]

Your only real option is to hold your meetings in the middle of field, and
for everyone to be naked.

Just think what could be done with a parabolic microphone and a
telephoto lens.

 

[paulmd]

[...]

Sorry for my rather unhelpful reply, I'm having one of my moments
where I only talk to microcontrollers.

No problems.

Seriously though. There's very little in world that's so
important. I've worked with people that would *record* meetings
thinking they were of vital importance when in actual truth, no one
could care less.

I guess it would just cause people to be more careful about what
they say. I'm unable to view those videos you've supplied as this
is a development machine without any clutter on it.

eBay could be a good place to buy such things though. All sorts of
stuff comes out of the AsiaPac.

This is to document something quite serious.

Are you the trying to be the documenter, or trying to avoid being the
documentee?
Or both?

 

[Arno Wagner]

You man there actually is something which will detect MP3 recorders?

Detection is a minor problem. Correct identification is the
issue. This is likely infeasible, unless you have the
specific recorder in question beforehand. And remember
that you wanted to know whether it is recording. Even more
difficult....

Arno

 

[Mitch Crane]

You'd be surprised where people can hide things:

http://www.dailymotion.com/blog/video/575462?key=467i4l5zyuv3g7lzul2w64
rs1iaad00kom8c0ii3&play=1&referer=http%3A%2F%2Fsusiebright.blogs.com

Caution! NSFW!

Sure, but I don't think the MP3 recorder would work very well in there, so
the point is moot.

 

[kony]

Sure it is

Nope, not without the scenario.

Yep, and all are detectable, and all have signatures.

You have not established that the signature (difference) of
such a device can be discriminated from a different device.
The scenario has not been defined enough to know if the
device will be turned on within the distance of the
scanner/other detection device.

Random ideas that "something" similar is possible is not
same as application in a specific scenario.

Depends on who you ask
The OP is not the only one who wants to ensure no one is able to record
conversations, or hear conversations they should not be hearing.


He gave the scenario.

No. A hint, but not a full scenario might include something
like what happens if "something" is detected, both the full
purpose and result.

True enough, but the technology is there to do what is being requested. Now
if the OP can afford it, or even obtain it is a different issue.

You have not established this. That some fields can be
detected, that it can be known if something is running, is
not same thing as knowing a digital recorder is running.
This difference is quite important in many scenarios because
OTHER types of devices are far more common in modern society
than digital recorders.