In case you've ever wondered, a blast from a Taser - the electronic gun police use to stun criminals - hurts.

It's like having nail guns applied to your hands and feet while you're being dunked in a vat of boiling water. I learned this the hard way, during a live demonstration at the Computer Electronics Show in Las Vegas, which ended Sunday. (Taser International showed up, because it is bringing a model to the consumer market, for personal protection, in July.)

Worse, you remain fully conscious. So for the single second the 50,000 volts from the gun coursed through my system, I could hear myself shout, "AAH! STURG! AAH!" at the top of my lungs in the crowded Las Vegas Convention Center.

At least I didn't fall to my feet, or so I thought.

"I was holding you up," said Mark Johnson, government affairs manager at Taser. "Don't you remember? At the end, you were on the ground." "Do it again. The shutter didn't click," the guy who had agreed to take my picture said. "Yeah, do it again," the 30 people who had gathered around the booth to watch me writhe yelled. I refused.

In the tech world, there are companies developing products that will do things for you, but there's also a small but growing number promoting products that will do things to you.

Medicine, many say, will be revolutionised in a few years, as silicon is combined with manufacturing techniques into testing equipment. Sensant, for example, has developed tiny silicon drums that can produce better-defined ultrasound images of tumours than traditional techniques can. Verimetra is promoting chips for catheters that can monitor blood temperature.

And then there are those bridging the body-machine gap in the consumer market. Among them:

Taser International
The Taser "personal energy weapons" coming to the consumer market are similar to the ones the U.S. military in Iraq and cops all over the United States are using. In a nutshell, the gun shoots a metal pointer that trails up to 15 feet of metal wire.

When the pointer hits a conductive surface like a body, 50,000 volts of electricity flow. A typical blast goes on for a paralysing 10 seconds but can last up to a full minute. A concealable 7-ounce model will cost about US$999, while bulkier home models will sell for about US$500.

Long-term health impacts have yet to be found, Johnson said. Police have had to use these weapons on a 7-year-old kid, on a 93-year-old man and on people with pacemakers, as well as in other situations. No one has died, according to Taser. Confetti-like tags spring out of the gun when it's shot, too - so it can be traced, if used in criminal activity. Still, do you want a nonlethal gun in the same home as a 13-year-old boy?

SSD
Founded by former Nintendo employees in Japan, SSD plans to come out this summer with a series of virtual-reality TV games. In the baseball and tennis games, people swing a real bat (or racket) at a ball coming at them on the screen. In bowling, they swing - but don't toss - a ball at a virtual set of bowling pins. Golf is expected to come out later. At the heart of the system is the Xavix multimedia chip. Sensors in the bats and rackets transmit data about the velocity and trajectory of the moving objects in your hand to a console containing the chip, which then renders images of what might have occurred in reality.

Overall, the Xavix system does fool your body into actually performing these motions as you might in real life. In the bowling game, you end up in that Earl Anthony tuck. However, the scores seem a bit inflated - everyone seemed to be rolling spares. The console will cost US$79.95, with each game selling for US$49.95.

Nexstar Sales
The US$499 Rhythm Touch is an electronic muscle stimulator. Like the transcutaneous nerve stimulator chiropractors use, this device sends electronic impulses through electrodes attached to the body to stimulate blood flow, which washes away lactic acid.

It's big in South Korea, where another company sells a device to stimulate brain waves. The Rhythm Touch's voltage ranges from 2.3 to 142 volts. It's interesting, and it seems to work, but it comes with a major design flaw. Scrolling the control knob down turns the voltage up - leading to my second larger-than-life encounter with electricity in a single day.

The Guitammer Co.
"ButtKicker Goes Consumer," Guitammer's press release reads. The ButtKicker is a vibrating platform that plugs into a home theatre or stereo, interprets the soundtrack and then shakes furniture accordingly. Imax theatres and some Disney rides use the same technology. Although it's supposed to bring realism to action movies, it can be a boon to neighbours of action film aficionados.

"With this, you don't need to turn up the subwoofer as much to hear it," a Guitammer representative said. The shaking platform and amplifier cost about US$700.

ASP
ASP specialises in high-intensity flashlights and pepper spray guns that come in designer colours and customised, laser-etched logos. "Is this legal in New Jersey?" one attendee asked about a purple pepper spray gun that fits on a keychain.

"Nothing is legal in New Jersey," the company representative said.

biography
Michael Kanellos is a senior department editor at CNET News.com, where he covers hardware, scientific and research issues, and start-up companies. He holds qualifications from Cornell University and Hastings College of the Law. He has worked as an attorney and a freelance travel writer, among other occupations.

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