At last year's Gadgetoff convention in New York, the Department of Homeland Security's undersecretary of science and technology showed off the latest and greatest in nonlethal weapons: a puke gun.

"The dazzler is a sea-sickness machine," said Jay Cohen, a retired naval admiral, who brandished the weapon for the audience to see. The dazzler, formally called the LED Incapacitator, affects the body's equilibrium with a flashlight-shaped device with variously colored flashing laser lights, like a psychedelic disco ball.

"I'm not going to point it at you," he said. "I was with a group of GE executives yesterday, and I held it up like this, and just the reflection made them nauseous."

The audience of tech enthusiasts wanted the same demonstration, however. "Come on, do it," someone in the audience screamed. "Well, this is a tough audience," Cohen said. "Are there barf bags?"

The audience may have been laughing, but the device is no joke. It even has a fictional precursor: in the film, "Minority Report," police officers touch criminals with a "sick stick," which makes them instantly vomit.

Except science fiction now is reality, as an array of nonlethal weapons that make you temporarily blind, deaf or sick are nearing deployment.

For decades, nonlethal weaponry was largely limited to blunt-impact objects like bean bags and pellet guns. Taser, a neuro-muscular disruptor, became immensely popular with law enforcement, but its major drawback is its limited range; the military wants weapons that can go beyond tens of meters. Thus the interest in "directed energy" weapons, i.e. devices that use light, sound, or in the case of one device, heat waves, to deter enemies.

Laser "dazzlers," now gaining popularity in the military, are typically designed to temporarily disorient an attacker. "The different colors - alternating colors - definitely has a nauseating effect, and is more disorienting than one color," said Ti Casazza, whose Connecticut-based company, LE Systems, sells dazzlers to law enforcement and the military.