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

Then the only practical alternative remaining is to have them consent to and go through a metal detector, and of course it has to be actively manned to discriminate a potential recorder from some other device, object, etc.

If you find what might be an MP player, you won't be able to determine if it's recording, rather than playing, or if recording off the radio. Unless MP3 players become illegal devices, or at least clearly posted as banned on private premises, you can't justify a search or seizure either (depending on laws in your locale). If private property, the other party may still refuse a search and seizure attempt.

Even scanning for such a device's radiated energy at entrance to an area, that wouldn't prevent them from turning on the device later. Unless you have the expectation that you can seize such equipment, you should follow the same guidelines you should have otherwise- not saying anything of importance in the presence of someone who can't be trusted not to repeat, reproduce, etc., in any way.

Ultimately going to such extra lengths will tend to make people suspect you have something to hide and put your activities under more scrutiny.

On digital clock, it would read 3:00 and the PM indicator would be off.

On analoug clock, the big hand would be pointing at 12 and small hand at 3 and outside should be still dark (no sun)

What are you doing? Water divining with the twig split 90 degrees? Or searching for MP3 recorder output with the birch twig?

Thanks Kony. So the MP3 recorder is essentially undetectable during its operation. OK. Thanks.

Maybe that explains why I can't find any follow-on products for tape recorder detection while many of the the older devices are no longer available.

Joey wrote in news:Xns9858A18B4798171F3M4@127.0.0.1:

Well in that case, the farting and belching should work to keep them away and presto, no recordings, but you'll have to live with the stinky smell.

SC

help ham radio SC turn in your license

Acoustic energy then, what the microphone/audio detection picks up. (It will cover more frequencies that humans can hear.)

The pattern is on at a particular time then off, it varies in certain ways that will enable further analysis of any:

Intermediate Frequencies (IF) or Radio Frequencies (RF) given off by a device reacting to the pattern of sound. If there is any IF or RF detected that corresponds/matches the on off times of the pattern of sound, you know there is a device responding to the sound in the room.

A more sophisticated analysis of the detected response to the pattern, can provide a great deal of information about the device detected. That would be beyond the scope of your question, and your security clearance, as well.

Luck; Ken

It should not come as a surprise, that security concerns that deal in high level technological detection devices, don't advertise to the general public that much. Search harder.

Luck; Ken

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

I'm not so sure this technique will work with an IC that has constant current, continual encoding of even silence as a typical MP3 player/recorder is likely to use. There might be a theoretical difference but one far more difficult to measure than even anything at all from the device.

You would be surprised at what is being done. As one of my techs used to say. "Noise, what Noise". But then this stuff tends to be kind of pricey.

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. Switching devices certainly produce as much "noise" when they operate as analog devices, more in most cases. We have devices that can detect very, very low wattage signals.

Luck; Ken

Impmon wrote in news:b59oi2tuh78itfnupp6n0j04teksmeeuqp@

Not very helpful for those of us who are residing in prison with no access to an outside window.

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

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.

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

Trouble is that he cant know about the devices his doesnt detect.

i have seen a device used by an electrical instructor at a trade school. he does not like any Cell, recorders or electronic devices active while in his class. this device will buzz and vibrate in his pocket as he walks around the class, he can walk right up to the student that has something on.. it works by detecting a variation of known R.F. frequencies that helps him decide on an LCD screen of the device what it could be, and then it has wide band detection of any R.F. generation.. as you know, most devices do generate some R.F. of some freq.. i've seen it in use and its on the market... all i can say is by his words, "it works very good"

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.

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