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

[Ken Maltby]

"Joey" <no@no-email.com> wrote in message
news:Xns985CB7B67B49071F3M4@127.0.0.1...

On 13 Oct 2006, paulmd@efn.org <paulmd@efn.org> wrote:


Joey wrote:
On 11 Oct 2006, Aly <alison@logicsaysNOSPAM.com> wrote:

Joey <no@no-email.com> wrote in message
news:Xns98593B2AEAC71F3M4@127.0.0.1...
[...]

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?


I don't want to be recorded.

But I would like to know if I can be detected if I do attempt to make a
recording.

Your last sentence is why "kony" won't get his "make&model"
for such a detector. Or any more of a technical description than
I have given him, of how they work.

I note that he isn't supplying the "Make&Model" of his
undetectable MP3 Recorder. He provides an argument
that no such detector could exist, based totally on his
theories of what is possible, but then complains that no
one will provide him with more than a basic theoretical
description of the workings of a device, that its makers,
sellers (usually the same people) and users, don't want
working details generally available. Counter-surveillance
devices are like alarm systems, you don't want to tell
anyone the details of how one works. No one, who
knows, is going to provide "kony" the "proof" he is
demanding.

Luck;
Ken

 

[kony]

On Sat, 14 Oct 2006 18:01:47 +0100, Joey <no@no-email.com>
wrote:

On 14 Oct 2006, kony <spam@spam.com> wrote:

On Fri, 13 Oct 2006 16:37:24 -0800, "Dana"
raff242@yahoo.com> wrote:

[...]

It's not my issue to claim detection of different devices
proves detection of an MP3 player recording. Rather, it is
your burden to be specific with the claim that it's possible
by showing even one reproducible example.

We have no reason to believe a scenario like the OP has (too
vaguely) posed, would allow identification of a device as an
MP3 player that is recording. Identifying the existence of
"some" kind of device, then a search uncovering this device
and a physical examination to determine that it is recording
(looking at the screen or lights) is another matter.


I can clarify whatever you are unsure about if it helps.

The specific scenario should have been, needed to be
mentioned at the opening of the thread. Because it wasn't,
the time spent on the thread wasn't very productive and many
have lost interest.

 

[kony]

On Sat, 14 Oct 2006 16:40:38 -0500, "Ken Maltby"
<kmaltby@sbcglobal.net> wrote:

But I would like to know if I can be detected if I do attempt to make a
recording.

Your last sentence is why "kony" won't get his "make&model"
for such a detector. Or any more of a technical description than
I have given him, of how they work.

I would find any test of any existing piece of equipment, a
great start towards proving an MP3 player can be detected
(as an MP3 player, since it may not be enough to identify a
mere presence of an electronic device).

I note that he isn't supplying the "Make&Model" of his
undetectable MP3 Recorder.

Recall that I'd mentioned the issue of scenaro already.
What is or is not detectable depends on scenario. Can they
seize ALL unidentified devices? Will the person be in a
random or controlled environment? Indoors or out? Will the
person carrying on the conversation need have a concealed
detector that monitors in realtime, and at what distance, or
only an initial or point-of-entry scan? What other devices
are known to be present in the vicinity?

I have never suggested it was impossible to detect that
someone electronic *exists* in general. Pinpointing the
device, identifying it, or even finding that it exists in a
specific scenario, let alone that it's recording, is what I
dispute has not been proven or even reasonably suggested.

Randomly pick a small battery powered MP3 player. Remember
that I need not pick _ONE_ because such a concealed device
is not limited to being only ONE type of recording MP3
player, the detection equipment would have to be able to
detect any and (practically) all types of recorders, but not
detect any other common devices, not excessive false
positive alerts.

He provides an argument
that no such detector could exist, based totally on his
theories of what is possible,

Based on no details that are useful to discriminate what an
MP3 player is and it's operation in recording.

If the topic had been detecting a RF transmitter of some
sort, or a know class of substance like explosives, that is
a different matter. Both have a few known signatures.
So I suggest that until you can describe what the unique
signature is that is unique to recording MP3 players, there
is no way to detect them, and only them, selectively.

but then complains that no
one will provide him with more than a basic theoretical
description of the workings of a device, that its makers,
sellers (usually the same people) and users, don't want
working details generally available.

There is no basic theoretical description that has been
provided relating to an MP3 player- the whole purpose of the
thread. This is a key detail that cannot be overlooked.
That some generalized similar concept of "detecting" some
other thing is possible, can only be held true if there are
unique detectable, in the specific scenario, attributes
common only to MP3 players, or perhaps by extension, all
small digital recorders but not other devices.

Counter-surveillance
devices are like alarm systems, you don't want to tell
anyone the details of how one works. No one, who
knows, is going to provide "kony" the "proof" he is
demanding.

So what we have is a generalized concept of "it works for a
secret reason". Sorry but that is anything except a
reasonable argument, let alone proof of concept alone.

We have to have at least 3 things:

1) A specific, exact scenario.

2) A method for discriminating recording MP3 players from
everything else, in the exact scenario. Not some vague
concept of detecting semiconductors, a mere HF signal or
anything else that is not unique to a multitude of different
MP3 players.

3) A device that can reliably use that method in that
scenario.

#2 is the linchpin, #3 may indeed be possible after #2 is
resolved to #1. So it is with any purpose built device.

 

[Dana]

"Ken Maltby" <kmaltby@sbcglobal.net> wrote in message
news:3YmdncDItbzDxKzYnZ2dnUVZ_v2dnZ2d@giganews.com...

"Joey" <no@no-email.com> wrote in message
news:Xns985CB7B67B49071F3M4@127.0.0.1...
On 13 Oct 2006, paulmd@efn.org <paulmd@efn.org> wrote:


Joey wrote:
On 11 Oct 2006, Aly <alison@logicsaysNOSPAM.com> wrote:

Joey <no@no-email.com> wrote in message
news:Xns98593B2AEAC71F3M4@127.0.0.1...
[...]

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?


I don't want to be recorded.

But I would like to know if I can be detected if I do attempt to make a
recording.

Your last sentence is why "kony" won't get his "make&model"
for such a detector. Or any more of a technical description than
I have given him, of how they work.

I note that he isn't supplying the "Make&Model" of his
undetectable MP3 Recorder. He provides an argument
that no such detector could exist, based totally on his
theories of what is possible, but then complains that no
one will provide him with more than a basic theoretical
description of the workings of a device, that its makers,
sellers (usually the same people) and users, don't want
working details generally available. Counter-surveillance
devices are like alarm systems, you don't want to tell
anyone the details of how one works. No one, who
knows, is going to provide "kony" the "proof" he is
demanding.

And now we will see Kony saying he knew that there was no such device, and
that we were just spouting garbage.

 

[Alexander Grigoriev]

Many cellphones have dictophone capability. How do you tell if the cellphone
in the visitor's pocket is not recording? The phone could be also simply
connected to another remote one, which would do the actual recording.

"kony" <spam@spam.com> wrote in message
news:curti2daiiikn4bqlqohuq2v9t1bli9dmp@4ax.com...

On Thu, 12 Oct 2006 16:48:32 -0800, "Dana"
raff242@yahoo.com> wrote:


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.



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.

 

[Alexander Grigoriev]

So it can tell semiconductor junctions of an MP3 recorder from semiconductor
junctions of non-recording devices?

Th OP question was detection not *any* semiconductor device, but a MP3
recorder. By the way, the recorder doesn't have to be in that room. Enough
to have a connected cellphone in a pocket.


"Dana" <raff242@yahoo.com> wrote in message
news:12j0msrju29j04a@corp.supernews.com...

Yeah, so what. There are devices that can detect semiconducter junctions.
MP3 players have semiconductor junctions, hence they can be detected.


Now how about the phones that can record?

They also have semiconductor junctions, hence they can also be detected.

 

[Alexander Grigoriev]

Hogwash.

MRI detects primirily concentration of hydrogen atoms. It requires quite
strong magnetic field with precise gradient. What you describe is using
different principles.

"Dana" <raff242@yahoo.com> wrote in message
news:12j0msrju29j04a@corp.supernews.com...

Hogwash.
You seem not to understand what can be done with electronics.
There are some devices that use the priciples of a MRI and shrink it down
to
a hand held sized device to scan for explosives. Since the compounds in
explosives give off a unique signature after being exposed to a strong
magnetic field, that signature is then stored in memory. Now your sensor
emits a magnetic field, and the reciever looks for the signature of the
explosives.
So it is only a matter of expanding your signature library, and your
receiver can be programmed to look for pretty much anything.
This is only one of many new tools that are out.
The semiconductor junction detector has been out for around 30 years.

 

[Dana]

"Alexander Grigoriev" <alegr@earthlink.net> wrote in message
news:W3gYg.11480$o71.7489@newsread3.news.pas.earthlink.net...

So it can tell semiconductor junctions of an MP3 recorder from
semiconductor
junctions of non-recording devices?

Th OP question was detection not *any* semiconductor device, but a MP3
recorder. By the way, the recorder doesn't have to be in that room. Enough
to have a connected cellphone in a pocket.

Yep, and that can be detected.
What you do with the knowledge that the person has an electronic device that
may or may not record is up to you and what you want to do.

 

[kony]

On Sat, 14 Oct 2006 19:01:06 -0800, "Dana"
<raff242@yahoo.com> wrote:

"Alexander Grigoriev" <alegr@earthlink.net> wrote in message
news:W3gYg.11480$o71.7489@newsread3.news.pas.earthlink.net...
So it can tell semiconductor junctions of an MP3 recorder from
semiconductor
junctions of non-recording devices?

Th OP question was detection not *any* semiconductor device, but a MP3
recorder. By the way, the recorder doesn't have to be in that room. Enough
to have a connected cellphone in a pocket.

Yep, and that can be detected.

By that you must specifically mean the cell phone.
Clear details matter a lot.

What you do with the knowledge that the person has an electronic device that
may or may not record is up to you and what you want to do.

It's essentially useless information because in modern
societies every other person has a cell phone or beeper, MP3
player or whatever. One could not conduct business in an
environment where they had to make some random speculation
every time they came across the existence of an unknown
electronic device, but as importantly, it still has not even
been established than in any specific scenario, the MP3
recorder would be detected at all. yes it's possible to
detect that an object exists, but it's also possible to have
a scenario where the testing method doesn't detect it.

 

[Dana]

"Alexander Grigoriev" <alegr@earthlink.net> wrote in message
news:Z8gYg.11485$o71.4823@newsread3.news.pas.earthlink.net...

Hogwash.

Yep, that is all you have.
Another such technology is called Quadrapole Resonance or QR. Originally
developed by the Department of Defense to detect land mines, QR directs a
beam of radio waves at an object. The radio waves will penetrate the object
and infuse whatever is inside. When the radio waves pass through an
explosive material, the molecules of that material will polarize or develop
a small electrical charge. As the molecules lose their charge, they emit a
very weak radio frequency signal that can be picked up and analyzed to
detect explosives.
Because it relies on harmless radio waves that are easy to produce and
monitor, this technology is considered to be one of the most promising in
the field.

MRI detects primirily concentration of hydrogen atoms. It requires quite
strong magnetic field with precise gradient. What you describe is using
different principles.

And another one that needs to keep up on technology
Here are some links that will explain what I am talking about.


http://gazette.gmu.edu/articles/4925/
Sauer's studies are focused on nuclear quadrupole resonance (NQR), a type of
radio frequency spectroscopy that can help identify many substances without
the use of a large static magnetic field

http://www.americanscientist.org/template/AssetDetail/assetid/39131

The phenomenon of nuclear quadrupole resonance is akin to nuclear magnetic
resonance, which is the basis of magnetic-resonance imaging. But unlike MRI
scanners, instruments based on nuclear quadrupole resonance are not required
to generate strong magnetic fields.

"Dana" <raff242@yahoo.com> wrote in message
news:12j0msrju29j04a@corp.supernews.com...


Hogwash.
You seem not to understand what can be done with electronics.
There are some devices that use the priciples of a MRI and shrink it
down
to
a hand held sized device to scan for explosives. Since the compounds in
explosives give off a unique signature after being exposed to a strong
magnetic field, that signature is then stored in memory. Now your sensor
emits a magnetic field, and the reciever looks for the signature of the
explosives.
So it is only a matter of expanding your signature library, and your
receiver can be programmed to look for pretty much anything.
This is only one of many new tools that are out.
The semiconductor junction detector has been out for around 30 years.

 

[Dana]

"kony" <spam@spam.com> wrote in message
news:1la3j2ligfll1f4c1kjmpg94hne8tqfm46@4ax.com...

On Sat, 14 Oct 2006 19:01:06 -0800, "Dana"
raff242@yahoo.com> wrote:


"Alexander Grigoriev" <alegr@earthlink.net> wrote in message
news:W3gYg.11480$o71.7489@newsread3.news.pas.earthlink.net...
So it can tell semiconductor junctions of an MP3 recorder from
semiconductor
junctions of non-recording devices?

Th OP question was detection not *any* semiconductor device, but a MP3
recorder. By the way, the recorder doesn't have to be in that room.
Enough
to have a connected cellphone in a pocket.

Yep, and that can be detected.

By that you must specifically mean the cell phone.

No, by that I mean any electronic device, which may or may not be used to
record conversations.

What you do with the knowledge that the person has an electronic device
that
may or may not record is up to you and what you want to do.

It's essentially useless information

Nope, it will tell you that the person has an electronic device that may or
may not be used to record your conversation or take pictures.
This is where security comes in, and how much security you want to enforce.

 

[Ken Maltby]

"kony" <spam@spam.com> wrote in message
news:a1u2j293ah62disl7aekcp97j4gofq7d6v@4ax.com...

On Sat, 14 Oct 2006 16:40:38 -0500, "Ken Maltby"
kmaltby@sbcglobal.net> wrote:


But I would like to know if I can be detected if I do attempt to make a
recording.

Your last sentence is why "kony" won't get his "make&model"
for such a detector. Or any more of a technical description than
I have given him, of how they work.

I would find any test of any existing piece of equipment, a
great start towards proving an MP3 player can be detected
(as an MP3 player, since it may not be enough to identify a
mere presence of an electronic device).



I note that he isn't supplying the "Make&Model" of his
undetectable MP3 Recorder.

Recall that I'd mentioned the issue of scenaro already.
What is or is not detectable depends on scenario. Can they
seize ALL unidentified devices? Will the person be in a
random or controlled environment? Indoors or out? Will the
person carrying on the conversation need have a concealed
detector that monitors in realtime, and at what distance, or
only an initial or point-of-entry scan? What other devices
are known to be present in the vicinity?

I have never suggested it was impossible to detect that
someone electronic *exists* in general. Pinpointing the
device, identifying it, or even finding that it exists in a
specific scenario, let alone that it's recording, is what I
dispute has not been proven or even reasonably suggested.

Randomly pick a small battery powered MP3 player. Remember
that I need not pick _ONE_ because such a concealed device
is not limited to being only ONE type of recording MP3
player, the detection equipment would have to be able to
detect any and (practically) all types of recorders, but not
detect any other common devices, not excessive false
positive alerts.

He provides an argument
that no such detector could exist, based totally on his
theories of what is possible,

Based on no details that are useful to discriminate what an
MP3 player is and it's operation in recording.

If the topic had been detecting a RF transmitter of some
sort, or a know class of substance like explosives, that is
a different matter. Both have a few known signatures.
So I suggest that until you can describe what the unique
signature is that is unique to recording MP3 players, there
is no way to detect them, and only them, selectively.

but then complains that no
one will provide him with more than a basic theoretical
description of the workings of a device, that its makers,
sellers (usually the same people) and users, don't want
working details generally available.

There is no basic theoretical description that has been
provided relating to an MP3 player- the whole purpose of the
thread. This is a key detail that cannot be overlooked.
That some generalized similar concept of "detecting" some
other thing is possible, can only be held true if there are
unique detectable, in the specific scenario, attributes
common only to MP3 players, or perhaps by extension, all
small digital recorders but not other devices.


Counter-surveillance
devices are like alarm systems, you don't want to tell
anyone the details of how one works. No one, who
knows, is going to provide "kony" the "proof" he is
demanding.

So what we have is a generalized concept of "it works for a
secret reason". Sorry but that is anything except a
reasonable argument, let alone proof of concept alone.

We have to have at least 3 things:

1) A specific, exact scenario.

2) A method for discriminating recording MP3 players from
everything else, in the exact scenario. Not some vague
concept of detecting semiconductors, a mere HF signal or
anything else that is not unique to a multitude of different
MP3 players.

3) A device that can reliably use that method in that
scenario.

#2 is the linchpin, #3 may indeed be possible after #2 is
resolved to #1. So it is with any purpose built device.

All this proves is that you have not read or understood
my earlier posts. I described the way actual devices
operate to detect any device that is detecting audio. It
shouldn't be hard to realize that any device that is
responding to a pattern of sound is a threat. For a
recorder, of any kind, to record the audio in a room
it must detect it, and amplify the detected signal.
These processes can be detected, if this processing
matches the on and off timing of a known pattern
of sound, (which you control) you can isolate the
device. (Your "2" above.)

I hope you aren't going to say that while this type
of detector can detect that there is a device
responding to the sound in the room, and help you
locate it; this hasn't identified the device as an MP3
recorder. I would think even you realize that it is
of no importance what the device is, that is responding
to the audio pattern, it would need to be considered
a live threat.

You might check into why the most expensive
"White Noise Generators" include a means to inject
a user supplied signal into them.

Luck;
Ken

 

[Ken Maltby]

"Alexander Grigoriev" <alegr@earthlink.net> wrote in message
news:G_fYg.11479$o71.1389@newsread3.news.pas.earthlink.net...

Many cellphones have dictophone capability. How do you tell if the
cellphone in the visitor's pocket is not recording? The phone could be
also simply connected to another remote one, which would do the actual
recording.

Detecting and locating any device intentionally transmitting
an RF signal is trivial in relation to this discussion. But the
kind of device I have described can certainly detect that it
is responding to the audio pattern, and locate it.

Luck;
Ken

 

[kony]

On Sun, 15 Oct 2006 02:08:05 -0500, "Ken Maltby"
<kmaltby@sbcglobal.net> wrote:

1) A specific, exact scenario.

2) A method for discriminating recording MP3 players from
everything else, in the exact scenario. Not some vague
concept of detecting semiconductors, a mere HF signal or
anything else that is not unique to a multitude of different
MP3 players.

3) A device that can reliably use that method in that
scenario.

#2 is the linchpin, #3 may indeed be possible after #2 is
resolved to #1. So it is with any purpose built device.

All this proves is that you have not read or understood
my earlier posts. I described the way actual devices
operate to detect any device that is detecting audio.

You made a suggestion that was not resolvable to a
difference in operation of an MP3 player. With a constant
current and constant bitrate output, you'd essentially be
suggesting that from a distance you can discriminate which
bits are flowing on the bus to the memory, in what is likely
a shielded case. I find this highly unlikely.

It
shouldn't be hard to realize that any device that is
responding to a pattern of sound is a threat.

Sure, but even ignoring the issue of whether it's feasible
to have test sound patterns at all, we don't have any
evidence a digitally recording MP3 player will have a
detectable response in particular scenarios, if in any at
all.

For a
recorder, of any kind, to record the audio in a room
it must detect it, and amplify the detected signal.

The recorder does not necessarily need amplification prior
to digitization, it is commonly a single chip solution that
would not have to output to headphones either in this use.

These processes can be detected, if this processing
matches the on and off timing of a known pattern
of sound, (which you control) you can isolate the
device. (Your "2" above.)

"IF" the process existed, and "IF" the detection device was
suitable sensitive, and "IF" the scenario allowed proximity,
then perhaps it's possible. None of these three IFs can be
assumed yet.

I hope you aren't going to say that while this type
of detector can detect that there is a device
responding to the sound in the room, and help you
locate it; this hasn't identified the device as an MP3
recorder.

Not at all, I'm going to say the device won't detect the MP3
player recording at all in most scenarios, that it might
detect "something" electronic is in the room but that's all,
it won't ID it as an MP3 player nor that it is responding to
sound in the room. "Maybe" if you had it right up against
the recorder, but do you expect that scenario?

I would think even you realize that it is
of no importance what the device is, that is responding
to the audio pattern, it would need to be considered
a live threat.

You're drifting down a tangent that has not yet been
reached. I never argued that a detected response to an
audio pattern wasn't suspicious enough to draw a conclusion
about the operation of a device.

It still doesn't get us where we need to be, to detect a
recording MP3 player reliably and discriminate it from other
non-recording electronic devices. This is not the same as a
tape recorder.

 

[Ken Maltby]

"kony" <spam@spam.com> wrote in message
news:a744j2h4v404p8gi293tdqg2kn583n9h60@4ax.com...

On Sun, 15 Oct 2006 02:08:05 -0500, "Ken Maltby"
kmaltby@sbcglobal.net> wrote:



1) A specific, exact scenario.

2) A method for discriminating recording MP3 players from
everything else, in the exact scenario. Not some vague
concept of detecting semiconductors, a mere HF signal or
anything else that is not unique to a multitude of different
MP3 players.

3) A device that can reliably use that method in that
scenario.

#2 is the linchpin, #3 may indeed be possible after #2 is
resolved to #1. So it is with any purpose built device.

All this proves is that you have not read or understood
my earlier posts. I described the way actual devices
operate to detect any device that is detecting audio.

You made a suggestion that was not resolvable to a
difference in operation of an MP3 player. With a constant
current and constant bitrate output, you'd essentially be
suggesting that from a distance you can discriminate which
bits are flowing on the bus to the memory, in what is likely
a shielded case. I find this highly unlikely.

I was suggesting no such thing. I find your idea that an
ungrounded MP3 recorder has any significant shielding,
very unlikely. The recorder to be a threat and to respond
to sound must let sound waves through, even if it is a
contact microphone/sensor/transducer, and they require
significant amplification in their operation.

It is not necessary to know "which bits are flowing on
the bus to the memory", the detection takes place before
that is even an issue.

If you are going to pretend you understand how the
device I described operates, try to approach it from
a different angle than; finding a way it couldn't work,
then deciding that is what I must be describing.

It
shouldn't be hard to realize that any device that is
responding to a pattern of sound is a threat.

Sure, but even ignoring the issue of whether it's feasible
to have test sound patterns at all, we don't have any
evidence a digitally recording MP3 player will have a
detectable response in particular scenarios, if in any at
all.

So now you doubt that it's possible to generate a

controlled pattern of sound? (You wouldn't be
responsible for Rap "Music", would you?)

I'm no giving you "evidence". But I must have missed
your "evidence" that the device I described doesn't
work. Evidence is something besides your opinion,
or your interpretation of High School Physics and needs
to be based in proven limitations.

Try the following:
http://www.testequipmentdepot.com/ramsey/testequipment/rf1.htm
it's the cheapest way to even start to examine this issue with
an attempt to establish some "evidence", you should be able to
detect some response from a recording device. This is nothing
like the device I was describing, but if you can see a result with
this, even you would have to admit that much more sophisticated
devices can do what I've described.

For a
recorder, of any kind, to record the audio in a room
it must detect it, and amplify the detected signal.

The recorder does not necessarily need amplification prior
to digitization, it is commonly a single chip solution that
would not have to output to headphones either in this use.

Almost all audio detectors/sensors require amplification,

and those that don't, carry a significant bias current that
gets modulated, more than enough to be detectable with
modern equipment.

These processes can be detected, if this processing
matches the on and off timing of a known pattern
of sound, (which you control) you can isolate the
device. (Your "2" above.)

"IF" the process existed, and "IF" the detection device was
suitable sensitive, and "IF" the scenario allowed proximity,
then perhaps it's possible. None of these three IFs can be
assumed yet.

Isn't it fortunate that no one needs your agreement that it's
possible, to make and use such devices.

I hope you aren't going to say that while this type
of detector can detect that there is a device
responding to the sound in the room, and help you
locate it; this hasn't identified the device as an MP3
recorder.

Not at all, I'm going to say the device won't detect the MP3
player recording at all in most scenarios, that it might
detect "something" electronic is in the room but that's all,
it won't ID it as an MP3 player nor that it is responding to
sound in the room. "Maybe" if you had it right up against
the recorder, but do you expect that scenario?

I say that such devices can detect any device that is
responding to a supplied audio signal pattern. Any
device that is detecting the audio pattern. They can
detect anything electronic, that generates electrical
noise or signal when it detects acoustical energy.

There is a great deal more some of these devices
can do in the hands of a skilled operator/analyst.

It looks like we have established that you are going
to just deny the possibility. You can believe what
you wish, it has no impact on reality what so ever.

I would think even you realize that it is
of no importance what the device is, that is responding
to the audio pattern, it would need to be considered
a live threat.

You're drifting down a tangent that has not yet been
reached. I never argued that a detected response to an
audio pattern wasn't suspicious enough to draw a conclusion
about the operation of a device.

It still doesn't get us where we need to be, to detect a
recording MP3 player reliably and discriminate it from other
non-recording electronic devices. This is not the same as a
tape recorder.

You have been provided a description of how these devices
can do just that, your only answer seems to be that you don't
believe a device could work as I described. You provide no
explanation (much less evidence) of why it couldn't work.

You seem intent on saying "No they can't work." I know
that they most certainly do work. What point is there in
further argument, on that basis?

Luck;
Ken

 

[Aidan Karley]

In article <Xns985C3410202Daoneatwoathree@216.196.97.142>, Mitch Crane wrote:

Yeah, good point. I never considered an external mic. I guess the nude
office will have to ban labial studs. They should also ban scrotal studs in
the interest of fairness.

There's a relatively common type of mechanical treatment for impotence

in the shape of an implanted rod which can be extended in the corpus callosum
to ... Oh, I'm sure that you can work out the details.

So, Albert was spying on Vikki. I'm surprised the recordings weren't
included with the rest of the Diana Tapes.

--
Aidan Karley, FGS
Aberdeen, Scotland
Written at Sun, 15 Oct 2006 12:10 +0100, but posted later.

 

[Aidan Karley]

In article <12j0msrju29j04a@corp.supernews.com>, Dana wrote:

There are some devices that use the priciples of a MRI and shrink it down to
a hand held sized device to scan for explosives. Since the compounds in
explosives give off a unique signature after being exposed to a strong
magnetic field,

That signature ... would it be from the azide bonds in a heavy metal

azide, from the nitrate bonds in RDX or PETN cubane nitrate, or from the
nitrate bonds in the current scare-of-the-month acetone derivatives? It would
be a breath of fresh air if it were.
(If your chemistry isn't good enough to spot the trap in this question,
be very, very careful.)

--
Aidan Karley, FGS
Aberdeen, Scotland
Written at Sun, 15 Oct 2006 12:14 +0100, but posted later.

 

[Aidan Karley]

In article <curti2daiiikn4bqlqohuq2v9t1bli9dmp@4ax.com>, Kony wrote:

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.

More to the point, since someone was talking about an

office-like setting, would be things like SCR (triode) dimmer switches
built into the walls of the room, for perfectly good reasons. The
phrase is "false positive", and if anything they're even more corrosive
of ones confidence in the usability of a detection system than are
false negatives.
(Had a bad week last week with a poison gas detector system
going off every couple of hours. Every false positive meant that I had
to kit up with the breathing apparatus and go to check the situation
out.)

--
Aidan Karley, FGS
Aberdeen, Scotland
Written at Sun, 15 Oct 2006 20:46 +0100, but posted later.

 

[kony]

On Sun, 15 Oct 2006 09:32:39 -0500, "Ken Maltby"
<kmaltby@sbcglobal.net> wrote:

You made a suggestion that was not resolvable to a
difference in operation of an MP3 player. With a constant
current and constant bitrate output, you'd essentially be
suggesting that from a distance you can discriminate which
bits are flowing on the bus to the memory, in what is likely
a shielded case. I find this highly unlikely.


I was suggesting no such thing. I find your idea that an
ungrounded MP3 recorder has any significant shielding,
very unlikely.

Define significant. Many have grounded copper foil in them.
It's not as though this is a high powered device to begin
with, though, and would commonly have to be detected at a
distance.

The recorder to be a threat and to respond
to sound must let sound waves through, even if it is a
contact microphone/sensor/transducer, and they require
significant amplification in their operation.

No, you are thinking of older devices. There needs be no
amplification prior to the digitization chip which can run
at constant current, very low voltage and no easily
detectable response to room noise from a distance.

We might consider it mere coincidence that it is recording
something, because the means to that end are different than
in a recording device with a different (end) medium and
analog amplification.

It is not necessary to know "which bits are flowing on
the bus to the memory", the detection takes place before
that is even an issue.

You mean "IF" it could, it would.

If you are going to pretend you understand how the
device I described operates, try to approach it from
a different angle than; finding a way it couldn't work,
then deciding that is what I must be describing.

I'm not going to pretend anything, I'm suggesting you are
not describing an MP3 player in recording mode.

All the rest of your supportive argument hinges on being
able to detect a signal that may not exist at all, or in
cases where it does, are not sufficient strenth to measure
at any distance. Remember it is not enough to find one
particular MP3 player, nor a dissimilar device like a tape
recorder, that can be detected- it has to be effective
against the entire class of devices, or at the very least
the common ones available on the market.

 

[Dana]

"kony" <spam@spam.com> wrote in message
news:iep5j25iu386k0jk624a5fkjpuq206rmmf@4ax.com...

On Sun, 15 Oct 2006 09:32:39 -0500, "Ken Maltby"
kmaltby@sbcglobal.net> wrote:


You made a suggestion that was not resolvable to a
difference in operation of an MP3 player. With a constant
current and constant bitrate output, you'd essentially be
suggesting that from a distance you can discriminate which
bits are flowing on the bus to the memory, in what is likely
a shielded case. I find this highly unlikely.


I was suggesting no such thing. I find your idea that an
ungrounded MP3 recorder has any significant shielding,
very unlikely.

Define significant. Many have grounded copper foil in them.
It's not as though this is a high powered device to begin
with, though, and would commonly have to be detected at a
distance.

Still consumer electronics do not have very good shielding.
Hence it would be a very minor task to detect the sampling clock of the
recorder in question. And most of the times the sampling rate is specified
by the MFG.

The recorder to be a threat and to respond
to sound must let sound waves through, even if it is a
contact microphone/sensor/transducer, and they require
significant amplification in their operation.

No, you are thinking of older devices. There needs be no
amplification prior to the digitization chip which can run
at constant current, very low voltage and no easily
detectable response to room noise from a distance.

You still have the sampling rate, which requires a clock at that rate, so at
a minimum that clock can be detected.
And most designs would include an amplification stage prior to digitization,
as the levels from most mics will not be sufficient, and also to add
isolation between the input stages.