Disrupting Inductive Neck Loop Earpiece with EMP?

[Shidoshi]

I have currently made a small handheld EMP device originally from a 9V battery which later got converted into 8x9V batteries which was outputting 52.5V and down to 45V after a half hour or so, 500mAh batteries **** big time, will go on to 3000mAh once I figure out all the kinks in the current design though.

The reason for creating this small EMP is to block out the inductive neck loop system which students are using to cheat on their exams, they use an MP3 player and a wireless earpiece which captures the magnetic resonance at about 300Hz - 5300Hz, some even go to 8500Hz. Since I wasn't able to replicate this low output, I tried the EMP method.

The pulse works fantastically at around 1m range with some grounding issues however, the original design was only intended as a demo and at the original 9V nothing happened with the increase of power I managed to get the multimeter to show me 200V output from 8x9V batteries lol. At about 1m range the earpiece picks up the EMP as do 3V pc speakers, I need the pulse to be received in a 10x10m room though.

I was also thinking of digging up an ancient HAM schematic to output somewhere near the magnetic resonance the earpiece works on, if HAM and submarines can do it why can't we?

I'm seriously stumped as to what the best option for our centre is, one more point, it is important that the device can run on a small current, well actually, should be covert, able to be mobile, say in a backpack with a few 9V batteries or other power source that is small enough to conceive in a bag.

 

[blueroomelectronics]

LOLz you need something close to a nuclear blast for an EMP that size.

 

[Nigel Goodwin]

Am I missing something here?, why would you let students taking exams take electronics in with them?.

 

[blueroomelectronics]

It's not an EMP but it does seem like a RF noise generator / jammer. Most likely illegal anyway. Just take the headphones off the students.

 

[Shidoshi]

Micro earpiece on an inductive loop can be as small as 3mm in diameter and undetectable unless either jam a pen in someone's ear and potentially hurt them. The inductive loop can be wired under the stitching of the student's garments.

EMP doesn't need a blast to work, however at this magnitude it doesn't seem like a far off point.

RF is usually 30Mhz-300Ghz, WAY above the magnetic resonance range of 300Hz to 5800Hz (5.8Mhz) in this instance.

If a mobile phone can interfere with 3V PC speakers at a distance of 3m, why can't I generate an output that covers the inductive loop system?

 

[HarveyH42]

I would think that rather than trying to disrupt the earphones, why not work on a detector. The students know that bring electronics into an exam, is against policy. Just catch the offending parties, give them a failing grade, and let administration decide about disciplinary action. Faced with course failure or expulsion, doubt many would take the risk.

 

[audioguru]

Students are cheating on their exams with an MP3 player?
Is Morse Code used to modulate the nuclear blasts of EMP?
And the modulation is the basics of simple adding and subtracting?
For kids who are only 7 years old?
Why?

 

[Nigel Goodwin]

Micro earpiece on an inductive loop can be as small as 3mm in diameter and undetectable unless either jam a pen in someone's ear and potentially hurt them. The inductive loop can be wired under the stitching of the student's garments.

EMP doesn't need a blast to work, however at this magnitude it doesn't seem like a far off point.

As already mentioned, it's NOT EMP - which does need a 'blast' to work, the clue is in the name PULSE.

RF is usually 30Mhz-300Ghz, WAY above the magnetic resonance range of 300Hz to 5800Hz (5.8Mhz) in this instance.

You seem rather confused?, RF is about 100KHz upwards, and even lower is used for specialised purposes. 30MHz upwards is VHF and above.

5800Hz is also 5.8KHz (not MHz) and is a mid-high audio frequency.

If a mobile phone can interfere with 3V PC speakers at a distance of 3m, why can't I generate an output that covers the inductive loop system?

Because you're creating an illegal transmission?.

 

[JimB]

... is to block out the inductive neck loop system which students are using to cheat on their exams...

Presumably these are the same useless third world students who wash-up here on ETO wanting us to do their work for them.

I was also thinking of digging up an ancient HAM schematic to output somewhere near the magnetic resonance the earpiece works on, if HAM and submarines can do it why can't we?

You seem to completely misunderstand the scope and solution to the problem.

I'm seriously stumped as to what the best option for our centre is, one more point, it is important that the device can run on a small current,

Small current = low power = short range.

Solutions:

Search the students for ipods/mp3s/etc, if they try to bring them into the exam room, just fail them, end of story.

From what you say, this is an INDUCTIVE loop system being used to cheat in the exam, so, if you want a technical solution, run a loop of wire around the exam loom and feed it with the output of a large amplifier to create your own inductive loop system. The input of the amplifier is driven from a noise generator/raucus music source/a voice announcement saying "you have failed you useless students".

No need for covert, just let them know you will not put up with their cheating.

JimB

 

[Gauthamvg]

instead of designing a complicated and costly system to detect you can simple use the metal detector gates (like the one used in airport) or hand held detector.