A long time ago we heard about the UK considering testing out some non lethal directed energy gear. Basically a beam-based weapon which would cause a burning sensation to discourage a victim (or attacker), but not actually damage skin or leave burn marks. This is what the Joint Non-Lethal Weapons Directorate, JNLWD, has been exploring since 2005. But according to project engineer Wesley Burgei, they've still got a few bugs left to work out:

"We have established the minimum irradiance to cause a sensation and have characterised where thermal injury begins," he says. "But the exact operating irradiance which balances a useful military effect with a conservative margin of safety has not been nailed down yet."

In plain words? There are some itty bitty safety issues. Thankfully those will be ironed out before the weapons ever hit the streets due to some UN protocol on blinding laser weapons. It turns out that they forbid weapons which would penetrate the retina and cause blindness. It seems odd that a beam-based weapon could affect skin without damaging eyesight, but, according to Burgei, it's entirely possible to use a "retina safe" wavelength.

It's great that safety is a priority in the design and creation of these beam-based weapons, but Steve Wright, a non lethal weapons analyst at Leeds Metropolitan University, raises an interesting point about them:

"Persuading by pain rather than brain - through conversation - has led to push-button torture in the past. If it leaves no mark on the skin how will anyone prove it's been abused?"

Tasers and the like leave evidence, marks and traces of use, but once they're within proper safety limitations, beam-based weapons like the one being built by the JNLWD won't. Not to start the "Oh, no! They'll be abused!" train, but how will we regulate them? [New Scientist]

Those wacky Ladyada hardware hackers (Adafruit Industries) and Phil Torrone from MAKE Magazine, trawled the net and found the patent from the outside consulting firm that built the device for the government.

They discovered it flashes green LEDs at about 10Hz to induce its effects, and modified a Sears flashlight to build their own version called the BEDAZZLER. And true to form, they've put the schematics, source code, and circuit board layouts online so you can make one yourself. Watch it in action below. Fun! [Ladyada]

Police used the device to emit a painful shrill that forced demonstrators to cover their ears and withdraw while police threw tear gas and stun grenades. "Other law enforcement agencies will be watching to see how it was used," Pittsburgh's police bureau chief told the NY Times. "It served its purpose well."

Whether or not you think the protesters have a right to demonstrate or are anarchists without a permit to march, it's still pretty eye-opening to see tech like that used at home.

As a non-lethal weapon, sound canons have been mounted to vehicles by the U.S Army, installed on American warships to warn incoming vessels, defended private cruise ships against Somali pirates, and were at the ready (though not used) at the 2004 Republican National Convention in New York.

But this is the first time LRAD has been used against U.S civilians. According to reports, 20 people were arrested, but there were no serious injuries. [New York Times]

The key, apparently, is size. Older HPMs were too long to be deployed, but the one that went into testing last week at a military facility in Huntsville, Alabama ("The Rocket City") is five feet long and just six inches thick. "It's a big deal," Edl Schamiloglu, an EE professor at University of New Mexico told IEEE Spectrum. "The military would be able to actually use these."

The weapon in testing will reach peak power of 35 megawatts for just 100 to 150 nanoseconds, pulsing out a microwave beam that covers 2GHz to 6GHz frequencies. There goes your Wi-Fi, and maybe your cellphone too.

The coolest thing about the bomb is its key power component, the "flux compression generator." Not only does it have a name that clearly was given to it by Dr. Emmet Brown, but one of the Texas Tech researchers developing the thing had this to say about it: "The FCG is like a battery that runs on a stick of dynamite"—well, C4 actually, but we get the picture. Big ba-da-boom.

If you're electrically inclined, be sure to soak up the more seductively nerdy details of this 21st-century ordnance at IEEE Spectrum. [IEEE Spectrum via Gizmag]

The liquid is doctor-approved, too, with Israeli "medical and legal authorities approving the use of the foul-smelling liquid." That's probably because the Israeli scientists who created it drew their inspiration from nature.

The foul-smelling liquid squirted by angry or frightened skunks at their victims was analyzed by Israeli defence scientists and a synthetic version created for use in a weapon they call the "skunk bomb". Fired with great care, and from a respectable range, it is designed to force civilian protesters to disperse. Security forces would not be keen to arrest the victims, and they would be equally unwelcome at home.

Unless, of coure, they already lived in a sewer.

But anyway, if you're still curious about the smell, the Palestinian demonstrators described it as "similar to that of sewage." [News VOA via Danger Room]

It's a pretty insane idea, but one that's actually been proven to work, at least in a basic form.

Because the frequency of the sound heard is dependent on the pulse characteristics of the RF energy, it seems possible that this technology could be developed to the point where words could be transmitted to be heard like the spoken word, except hat it could only be heard within a person's head. In one experiment, communication of the words from one to ten using "speech modulated" microwave energy was successfully demonstrated. Microphones next to the person experiencing the voice could not pick up the sound. Additional development of this would open up a wide range of possibilities.

...

This technology requires no extrapolation to estimate its usefulness. Microwave energy can be applied at a distance, and the appropriate technology can be adapted from existing radar units. Aiming devices likewise are available but for special circumstances which require extreme specificity, there may be a need for additional development. Extreme directional specificity would be required to transmit a message to a single hostage surrounded by his captors. Signals can be transmitted long distances (hundreds of meters) using current technology. Longer distances and more sophisticated signal types will require more bulky equipment, but it seems possible to transmit some of the signals at closer ranges using man-portable equipment.