Pocket EMP device with a disposable camera's flash?

[sk8terg1rl]

Hey guys, I heard a tale about someone successfully building an
improvised pocket EMP device that fried RFID tags. IIRC he apparently
removed the flashbulb and replaced it with a simple LC tank circuit.

Do you guys think this is feasible? Will this device fry all
electronics indiscriminately, or only those which are tuned to receive
at particular frequencies?

 

[Ian Stirling]

Hey guys, I heard a tale about someone successfully building an
improvised pocket EMP device that fried RFID tags. IIRC he apparently
removed the flashbulb and replaced it with a simple LC tank circuit.

Do you guys think this is feasible? Will this device fry all
electronics indiscriminately, or only those which are tuned to receive
at particular frequencies?

It would tend to kill primarily RF tags around the frequency that the LC
thingy is tuned to.

 

[Jim Thompson]

It would tend to kill primarily RF tags around the frequency that the LC
thingy is tuned to.

Don't aid the shoplifters ;-)

...Jim Thompson

 

[martin griffith]

Don't aid the shoplifters ;-)

...Jim Thompson

Don't aid Big Brother


martin

 

[[email protected]]

Hey guys, I heard a tale about someone successfully building an
improvised pocket EMP device that fried RFID tags. IIRC he apparently
removed the flashbulb and replaced it with a simple LC tank circuit.

Do you guys think this is feasible? Will this device fry all
electronics indiscriminately, or only those which are tuned to receive
at particular frequencies?

https://events.ccc.de/congress/2005/wiki/RFID-Zapper(EN)

"Caution: RFID-Zappers don't comply with FCC rules."

 

[Ancient_Hacker]

Hey guys, I heard a tale about someone successfully building an
improvised pocket EMP device that fried RFID tags. IIRC he apparently
removed the flashbulb and replaced it with a simple LC tank circuit.

Nope, can't do it that way. The xenon flashtube is directly connected
across the main storage capacitor. It's triggered into firing by a
high voltage pulse applied to a thin wire that's wound around the tube.


A LC circuit of course can't be triggered that way. I guess you could
put the LC in series with the flashtube, so there's be a several amp
pulse into it. But that's not going to generate much of a RF field.

Much better EMP can be done with public-domain designs, just use Google.

 

[sk8terg1rl]

Don't aid the shoplifters ;-)

If only it were so simple.

Britain is slowly but surely turning into a despotic, Orwellian
dystopia. Not that I will be doing anything, I hasten to add.

Britain: the most spied on nation in the world
http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/11/02/nspy02.xml

Your life in their lens
http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/11/02/nspy102.xml

'Big Brother society' fears
http://news.bbc.co.uk/2/hi/uk_news/6108660.stm

Warning over surveillance society
http://www.guardian.co.uk/uklatest/story/0,,-6187445,00.html

 

[sk8terg1rl]

Nope, can't do it that way. The xenon flashtube is directly connected
across the main storage capacitor. It's triggered into firing by a
high voltage pulse applied to a thin wire that's wound around the tube.


A LC circuit of course can't be triggered that way. I guess you could
put the LC in series with the flashtube, so there's be a several amp
pulse into it. But that's not going to generate much of a RF field.

Can't you could just break the flashtube and effectively turn it into a
large resistor, and "short circuit" the LC in what were its input
leads? AIUI all you're really taking from the disposable camera is its
capacitor, the means to charge it and the trigger to discharge it. All
of which should work independently of whether you have a flashtube or
LC circuit connected to it.

Much better EMP can be done with public-domain designs, just use Google.

The other EMP devices I've seen require the use of some kind of
vircator assembly. This means nasty explosives (and potentially a LOT
of trouble) and it will be a highly visible one-off usage device.

Any other designs for innocuous devices that are reusable?

 

[Jim Thompson]

If only it were so simple.

Britain is slowly but surely turning into a despotic, Orwellian
dystopia. Not that I will be doing anything, I hasten to add.

Britain: the most spied on nation in the world
http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/11/02/nspy02.xml

Your life in their lens
http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/11/02/nspy102.xml

'Big Brother society' fears
http://news.bbc.co.uk/2/hi/uk_news/6108660.stm

Warning over surveillance society
http://www.guardian.co.uk/uklatest/story/0,,-6187445,00.html

So? Don't jerk off in public ;-)

...Jim Thompson

 

[sk8terg1rl]

So? Don't jerk off in public ;-)

It has less to do with the police catching legitimate criminals, than
criminalising the innocent and acting with impunity.

For example, the police who recently murdered an innocent, restrained
and unresisting man are back on duty (Rambo killed another guy today
too) and they weren't even *tried*. If that isn't an indication of
being above the law, I don't know what is.

It is easy for you to point fingers being a Yank where freedom is still
somewhat valued but I extend a very warm welcome to you to come to
Britain and see things for yourself.

Until then, please spare us your snide misinformed comments.

 

[Jim Yanik]

Can't you could just break the flashtube and effectively turn it into a
large resistor,

It does not turn into a resistor,it turns into an open circuit;a big air
gap.
You obviously do not know how a xenon flashtube works.

and "short circuit" the LC in what were its input
leads? AIUI all you're really taking from the disposable camera is its
capacitor, the means to charge it and the trigger to discharge it. All
of which should work independently of whether you have a flashtube or
LC circuit connected to it.

Better learn HOW the flashtube is triggered and how a xenon flashtube
works.

Hint;the flashtube IS the switch.

 

[Didi]

It has less to do with the police catching legitimate criminals, than

criminalising the innocent and acting with impunity.

Frankly I was surprised the public debate to start this early (heard of
it
today on the BBC Worldservice).
For many years now I believe the obvious destination of
the path human society has taken - given no too great catastrophy
interrupts
that - is a zero privacy society. It is the only way things can work
out
and be accepted by most people - anyone can watch anyones activity
at any given moment, no exceptions. I am not sure I am ready to live in
such a society but then I doubt I will live long enough to have to...
Under the
score the change will be for the better, 0 privacy will also mean 0
lies,
which may have a dramatic effect on progress etc.
It is encouraging to see the English initiating the debate; trying to
stop the technology from utilization will of course be futile, although
it will take many years for things to settle.

Dimiter (in Seldon mode yet again

 

[Jim Thompson]

It has less to do with the police catching legitimate criminals, than
criminalising the innocent and acting with impunity.

For example, the police who recently murdered an innocent, restrained
and unresisting man are back on duty (Rambo killed another guy today
too) and they weren't even *tried*. If that isn't an indication of
being above the law, I don't know what is.

It is easy for you to point fingers being a Yank where freedom is still
somewhat valued but I extend a very warm welcome to you to come to
Britain and see things for yourself.

Until then, please spare us your snide misinformed comments.

Are the cameras anywhere but in _public_ places?

...Jim Thompson

 

[Didi]

Are the cameras anywhere but in _public_ places?

It is not just about public cameras. It is also about carrying a mobile
phone (how do you know what it is doing), electronic payments and
other traceable activities, online activity, etc. etc., the list may be
growing by the hour rather than by the day...

Dimiter

 

[Jim Thompson]

Are the cameras anywhere but in _public_ places?

It is not just about public cameras. It is also about carrying a mobile
phone (how do you know what it is doing), electronic payments and
other traceable activities, online activity, etc. etc., the list may be
growing by the hour rather than by the day...

Dimiter

Jim Thompson wrote: [snip]

Are the cameras anywhere but in _public_ places?

So turn off your phone when you're not using it. And don't make
electronic payments or do "other traceable activities".

Then they'll start _following_ you because you are acting
suspiciously.

When you _are_ using your cell phone, they already know where you are.
The phone company won't be cheated out of a penny.

Don't the British authorities still need a warrant to enter your home?

Just because you're paranoid doesn't mean that they're NOT out to get
you ;-)

Sheeeesh! Sounds like the Brits are raising a large crop of leftist
weenies.

...Jim Thompson

 

[sk8terg1rl]

It does not turn into a resistor,it turns into an open circuit;a big air
gap.
You obviously do not know how a xenon flashtube works.


Better learn HOW the flashtube is triggered and how a xenon flashtube
works.

Hint;the flashtube IS the switch.

OK, so if I understand correctly: the trigger pulse ionises the Xenon,
which then becomes conducting and the main discharge from the capacitor
follows.

Depending on the circuitry of the disposable camera, the capacitor's
discharge is either controlled by a second switch, or simply by virtue
of the Xenon becoming conducting.

If it is the former, no problem - that second switch simply needs to be
triggered or replaced to bypass it.

If it is the latter, then replacing the Xenon with an inductance coil
will cause the capacitor to discharge immediately after the trigger
pulse is fired.

So in theory it should work; correct me if I am wrong please.

 

[sk8terg1rl]

Frankly I was surprised the public debate to start this early (heard of
it
today on the BBC Worldservice).
For many years now I believe the obvious destination of
the path human society has taken - given no too great catastrophy
interrupts
that - is a zero privacy society. It is the only way things can work
out
and be accepted by most people - anyone can watch anyones activity
at any given moment, no exceptions. I am not sure I am ready to live in
such a society but then I doubt I will live long enough to have to...
Under the
score the change will be for the better, 0 privacy will also mean 0
lies,
which may have a dramatic effect on progress etc.
It is encouraging to see the English initiating the debate; trying to
stop the technology from utilization will of course be futile, although
it will take many years for things to settle.

Dimiter (in Seldon mode yet again

A slide down to a surveillance-fetish society is not inevitable.

People must simply realise that they must accept risk as part of
freedom. Trying to be obsessive about security and monitoring to
"ensure safety" will simply turn the society into a high tax-high
spending Socialist dystopia with certain groups of society above the
law and/or telling us what to do.

An example: I would rather have laws that enshrine our right to be
armed and defend ourselves, than rely on cops to do that. I am the best
guarantor of my security; not a 3rd party.

 

[John O'Flaherty]

OK, so if I understand correctly: the trigger pulse ionises the Xenon,
which then becomes conducting and the main discharge from the capacitor
follows.

Depending on the circuitry of the disposable camera, the capacitor's
discharge is either controlled by a second switch, or simply by virtue
of the Xenon becoming conducting.

If it is the former, no problem - that second switch simply needs to be
triggered or replaced to bypass it.

If it is the latter, then replacing the Xenon with an inductance coil
will cause the capacitor to discharge immediately after the trigger
pulse is fired.

So in theory it should work; correct me if I am wrong please.

I think the way it works is that the xenon tube is always connected
across the cap; the voltage builds up to several hundred volts,
somewhat under the spontaneous flashover voltage for the flashtube and
the flash unit is ready; then a trigger pulse is applied to make some
ions in the tube. Those are accelerated by the high voltage field,
collide with other atoms, make more ions, in an avalanche effect. The
xenon has broken down, its resistance drops to a very low value, and
the big current pulse ensues as the capacitor discharges. As he said,
the tube itself is the switch. Then, when the current through the tube
disappears, the ions recombine and you have an insulating tube again.
If you replace it with a coil, you'll never build up the capacitor
voltage in the first place. Putting your coil in series with the tube
will give you a big pulse into the coil, but as they said, probably not
enough to damage anything. The cap will only be holding a few joules of
energy.

I found this through google:
http://members.misty.com/don/samflash.html
Notes on the Troubleshooting and Repair of Electronic Flash Units and
Strobe Lights and Design Guidelines, Useful Circuits, and Schematics

 

[Didi]

An example: I would rather have laws that enshrine our right to be

armed and defend ourselves, than rely on cops to do that. I am the best
guarantor of my security; not a 3rd party.

Agreed 100% on that.
My point is, however, that technological progress will inevitably bring
with itself either a "zero secrets" society or something even worse
than Orwells (after all, he wrote 1984, not 2084....). I can't help
being
an optimist, so I imagine it will be the former.... Notice that 0
secrets
means 0 secrets, _no_ exceptions. This will actually be better than
todays hypocritic mess - although it will take some development
until we are ready for it.

Dimiter (still unable to quit the Seldon mode

 

[Mark]

If you want to zap your own RF ID tag, simply place it inside the
microwave oven along with your favorite pop corn...

It wouldn't be nice to zap someone elses...

Mark