Magnetic Tattle Tape Security Strips?
Magnetic Tattle Tape Security Strips?
(OP)
Hi,
Does anyone have any info on Tattle tape security Strips and how they can be magnetized and demagnetized and in particular how one can "sense" whether one and more than one strip is placed within a specfic area?
The 3M tattle strips seem to have 5 sections which are magnetised - any particular reason for this? - what is the principle involved in their detection?
What sort of magnetic field intensity is requied to magnetize these strips?
thanks
Does anyone have any info on Tattle tape security Strips and how they can be magnetized and demagnetized and in particular how one can "sense" whether one and more than one strip is placed within a specfic area?
The 3M tattle strips seem to have 5 sections which are magnetised - any particular reason for this? - what is the principle involved in their detection?
What sort of magnetic field intensity is requied to magnetize these strips?
thanks





RE: Magnetic Tattle Tape Security Strips?
RE: Magnetic Tattle Tape Security Strips?
RE: Magnetic Tattle Tape Security Strips?
RE: Magnetic Tattle Tape Security Strips?
<www.uspto.gov>
<nbucska@pcperipherals.com>
RE: Magnetic Tattle Tape Security Strips?
RE: Magnetic Tattle Tape Security Strips?
RE: Magnetic Tattle Tape Security Strips?
TTFN
RE: Magnetic Tattle Tape Security Strips?
thanks anyway!
RE: Magnetic Tattle Tape Security Strips?
hi,
thanks for the idea, we have the same study with 3M tattle tapes and its detection process
RE: Magnetic Tattle Tape Security Strips?
When doing so, it emitted a weak magnetic field with lots of odd harmonics - which were picked up by a sense coil and analyzed to verify that frequency contents and phasing was right. If so, an alarm was sounded.
There were also lots of even harmonics and no one could understand why. A soft strip should only produce odd frequencies like 3000, 5000, 7000 and so on. Until we found out that the eart's magnetic field pushed the B of the strip away from zero so that even hermonics were produced.
The strip was deactivated by magnetizing a hard magnetic backing material. Doing so forced the soft strip into the saturated mode and the 1000 Hz field had no influence on it.
That is the general principle for that kind of EM labels. And it is knowledge in public domain. See also http:
Gunnar Englund
www.gke.org
RE: Magnetic Tattle Tape Security Strips?
Yes I can detect the tattle tapes OK, but my problem relates to the detection of whether there is onl;y one strip or multiple strips in the same area and at close proximity?
Any ideas ?
I was thinking of somehow detecting the interference pattern from multiple strips but since the emitted frequencies are identical and most likely in phase they would be difficult to detect ?