What flashrate induces Epileptic Seizure?

I would like to make a high power cyan luxeon flasher to ward off would be attackers. Does anyone know what freq. best causes this effect? Thanks!

From this article:

http://serendip.brynmawr.edu/bb/neuro/neuro99/web1/Cenedella.html

"The likelihood of a seizure, as well as its type, in photosensitive individuals depends on the intensity, the contrast of the visual stimulus, and the specific frequency of flashing. Extensive EEG studies have shown that a flicker stimuli between 10 and 30 flashes per second induces the generalized epileptiform discharges and the clinical features characteristic of an epileptic seizure particularly well. Television, computer, and video game screens produce a 50 Hz flicker and a vibrating pattern at half the alternating-current frequency, or 25 flashes per second within the 10 to 30 flashes per second range. The vibrating pattern is only visible when sitting close to the television. Therefore, most television-induced seizures occur at viewing distances between 1.5 and two meters."

The thing to note is that they have to be a "photosensitive individual" for the flashing to have any effect. Do a search in Yahoo! for more...

Wouldn't it just be easier to learn the "Vulcan Death Pinch"?

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Slick said:
Wouldn't it just be easier to learn the "Vulcan Death Pinch"?

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LOL!

Or maybe just swift kick in the nads?

Well...every time i push the button on my Surefire E2 i feel like i want to vomit. /ubbthreads/images/graemlins/grin.gif

Sorry tonyb, i don't know the answer. I think Quickbeam's research is the closest you'll get to an answer. It would seem logical that intensity plays a great part in vomit inducing light strobing. I've heard rumors about such lights bring tested in the military and in law enforcement, but those lights use laser technology. I don't think you can get much more intense than that in a handheld form factor. An LED might work, but you'd have to be in close proximity for it to work...you might as well learn the Vulcan Death Pinch.

I do recall a few years back about a Japanese anime show that did a strobe feature at the end of an episode. There were numerous reports of kids becoming nauseous and going into seizures. The episode was promptly pulled from syndication. /ubbthreads/images/graemlins/ooo.gif /ubbthreads/images/graemlins/crazy.gif

You might want to do a Google search on the incident. It was national news, and brought up the subject of physiological effects of certain types of strobe lighting.

Keep in mind, though, that only a limited number of people were affected. It wasn't something I would really trust if I were being rushed by a 6'5",350 lb Gigantor.

P.S. -There was also a Simpson's episode on the subject (which was hilarious, as usual).

/ubbthreads/images/graemlins/smile.gif

i don't get nauseous when looking at a bright light, but if i go from a dark place to a bright place or stare at a bright light after my eyes have become accustomed to the dark, i'll just sneeze for no reason /ubbthreads/images/graemlins/confused.gif

I believe you want a frequency of between 7 and 12 herz (flash per second) and it will vary between these frequencies from person to person. note: epileptics are more sensitive to this, so anywhere arround these values usually works, but you can cause ANY person to enter into a seizure if you hit the right frequency. note: as you are probably not able to get any feedback with an EEC machine (experiments using one as feedback have enabled researchers to induce seizures in every patient in the trials) your best bet will be to produce a circuit that ramps up and down between these frequencies over a few seconds.

As a side note, a couple of years ago a mate of mine made a 'mind expander' circuit, basically it flashed a pair of LED's (built into a pair of sunglasses and pointing towards your eyes) at one frequency for a few seconds then changed to one at half the frequency.

You put on the glasses with your eyes closed and switched it on. When the flash frequency changed you suddenly started to see complex geometric patterns. I think the frequencies used were those similar to that of your brainwaves when you are sleeping.

p.s. excuse the 'edited' bit my keyboard seems to have dyslexia today (either that or my typing is cr*p).

Check out this thread from the Strategos board...

here

Vulcan "death pinch", kick to the nuts, epileptic seizure-inducing lights...........

Aragorn! Where are you buddy? This thread has your name all over it!! /ubbthreads/images/graemlins/yellowlaugh.gif

If all else fails, just kick that kid's *** the old fashioned way! /ubbthreads/images/graemlins/twak.gif

the frequencies are between8 and 35 Hz and the light has to be quite bright to evoke increased neuronal susceptibility to seizures. as this needs a photosensitive victim and because the chances are not very high that your attacker is one and chances of success under combat circumstances are very low even for those sensitive to strobe effects I would say:
learn karate! forget about a seizure provoking strobe light. even if the thought is somewhat cool.
bernhard, MD

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chamenos said:
if i go from a dark place to a bright place...i'll just sneeze for no reason /ubbthreads/images/graemlins/confused.gif

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I do the same thing, and it'll be like 3 sneezes in a row! /ubbthreads/images/graemlins/ooo.gif
Only happens when I go from the dark computer room to mid-afternoon Texas sun to get the mail. I'll get the funniest looks as I'm incapacitated, trying not to fall over from the back-blast of the sneeze!

I pitty the poor person who tries to take me down late at night with a tactical flashlight...they're gonna get a face full of snot /ubbthreads/images/graemlins/icon15.gif

-Jason

Dark to light sneezers, check this out.

http://www.straightdope.com/classics/a2_303.html

Photosensitive or not, this phenomenon is the reason that all fire alarm strobes in CA public buildings now need to be synchronized (randomly flashing strobes might accidentally hit that magic frequency).
There are LOTS of bucks having to be spent to make sure this small percentage of the population isn't affected during a fire alarm.

Neat write-up! Now I know why they didn't let me be a pilot.
Funny thing is that I've never had it happen when it was crucial that I don't sneeze. Never sneezed when riding my motorcycle (or mountainbike) in and out of the light. Never during military training when you're in the dark and a flare goes off or strobes suddenly go off. Never caused any driving accidents.

Just makes me look stupid when I'm with my friends when we walk out of the bar.

-Jason

Instead of trying to determine what frequency of flashing incapacitates an attacker, you might want to try making a SUPER BRIGHT variable flasher. I don't know how small one of these can be, but a safer alternative might be a SUPER BRIGHT flashlight in the end of a steel baseball bat. If the light doesn't get 'em, the bat will /ubbthreads/images/graemlins/twak.gif.

So, would one join the attacker in the induced seizure, or blind themselves by wearing a blindfold?

first one to wake up wins!! /ubbthreads/images/graemlins/poke2.gif

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arioch said:
I do recall a few years back about a Japanese anime show that did a strobe feature at the end of an episode. ...
P.S. -There was also a Simpson's episode on the subject (which was hilarious, as usual).

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I've seen that Simpson's episode before.
They were all watching a show called "Japanese Seizure Robots", their eyes would get all funny, and they'd all twitch and fall to the floor.

I don't know what the real show was, or the flash rate on the TV screen, but I'm sure Google.com would be able to dig up *something*.

mmm. the Maxabeam I'm seriously considering buying has a strobe feature..from about 10 bps (blinks per second) on up to nearly continuous, (appears as a slight flicker), I'm thinking "crowd control" -- ? heh. heh.