Schneier on Security

Clive Robinson • April 7, 2011 7:42 AM

There is work going back on “non lethal light weapons” for many many years (over 25years to my knowledge).

There are two basic types that I’m aware of one unpleasant the other down right nasty.

The unplesant one uses an intence light to overload the optical sensors in the eye and use up the visual purple, the result is to leave the person in a blank world.

For those who have been screened for diabetic retinopothy you will be aware of this when the camera flash is used to take the picture of your retina.

A second system is much more unpleasent and can induce fits vomiting and unconciousness.

We are probably all aware of the messages given with films and televison programes “warning the following contains flashing images…”

Well the bad news is we are all prone to being attacked by our optic nerves, if a high intesity light source is shone in the eyes and is modulated by certain wave forms it can cause significant disruption in the brain to induce certain states.

There is also a third trick which is to use just out of ordinary visable light at either the IR or UV ends of the band as this gets into the retina but does not always induce the protection mechanisums of flinching or closing down of the iris etc.

I’m not sure which camp these devices work in, but research done in the UK could cause a pig to vomit and or collapse at well over 50meters (a similar device using two achostic microwave sources could induce unconsciousness and death at well over six times that distance).

For some reason the research funding in the 1980’s for “non leathal weapons” for crowd control etc dried up, and the likes of the UK’s Defence Evaluation and Research Establishment got privatised (it became QinetiQ after a real knock down price sale and made certain people extrodinarily wealthy).

Clive Robinson • April 7, 2011 8:01 AM

I’ve just looked up the patent (I know Bruce does not like looking at them) and all I can say is there is an awful lot of known prior art.

http://www.patents.com/us-7866082.html

But simply it’s an over sized flash lamp using an arc light which is highly comutated.

As the UK’s Met Police photographic squad know, you can buy 1 million candle power flash lamps that with just the tiniest of adjustment produce a similar beam of light. They discovered some years ago that on some marches people did not like their photos being taken and the photo squad felt themselves under attack when six or eight of these flash lamps were shone in their faces and digital cameras.

One of the reasons the Met Photo Squad are so hated is that they were set up to make a profit, in that the Met Police have been known to sell the photographs and attendant personal details to various private security concernces, which were then used as “psudo evidence” against the people to try and effect their livelyhood, liberty and assets.

Clive Robinson • April 7, 2011 12:59 PM

@ Harry,

“Isn’t this called a laser pointer?”

No the patent definatly says “non monochramatic” and gives a broad frequency range of wavelength.

The problem with lasers and peoples eyes is they give comparativly little stun compared to the energy level. Therefor lasers will burn holes in you retina without making you even blink (which is one reason to use them in opthalmic surgery).

Look at the patent link I gave and judge for yourself but I’m calling “flash light” on this device plus enough prior art that would have already expired (should anyone have been daft enough to patent it).

Oh and the patent contains sufficient information about the (supposed) inventor so you can track them down.

Maybe time to track down those named on the patent and invite them to defend the granting of the patent.