When Randy McConnell equipped warehouse workers at Smith Drug Co. with wearable computers, production increased by 20%. "And our error rate went down to nothing," says the IT director at the US-based drug wholesaler.

Relaying instructions from a central server, the wearables from Pittsburgh-based Vocollect Inc. tell workers which bins to go to and how many items to pull, he explains. The waist-mounted computers weigh less than a pound and are curved to fit comfortably. Users wear headsets with microphones to receive and confirm instructions.

"Previously, they had a clipboard with 25 items per sheet," McConnell recalls. "Now, they don't have to look at the paper. Their hands are free, and all they have to do is listen and think."

Training is minimal. "It takes about 30 minutes to train a voice-recognition template for one person and no more than 30 minutes to train the person," McConnell says. "Within one hour, they can be really productive."

No hands

The market for wearable computers amounts to just US$150 million, but the annual growth rate is 20% to 25%, says David Krebs, an analyst at Venture Development. (The market doesn't include conductive textiles or special-purpose wearable proc­essors such as those used in medicine and sports.)

"In the 1990s, you saw people deploying wearables in order to get a competitive advantage, but now you need them to be competitive at all," says Brian Viscount, a vice president at Motorola Inc., which is a leading vendor in the wearable field, thanks to its acquisition of Symbol Technologies.

Motorola's 11-oz. unit, based on Windows CE, is worn on the forearm and relies on a voice interface. Prices range from US$3,000 to US$3,500, says Viscount.

Wearables are gaining popularity in "a niche industrial and government market where freeing one's hands enhances the capabilities of the user," Krebs explains. "We have seen strong successes in warehouses and some in the military for situational awareness, with some adoption in health care and maintenance. But the big issue in the field is identifying appropriate applications."

That doesn't seem to be a problem for some vendors. "Our part of the market is doubling every year," says Ross Smith, president of Quantum3D, which makes wearables for the military and police. "A lot of new applications are springing up, just as in any other field where you have an enabling technology, especially around what they call C4ISR [command, control, communications, computer, intelligence, surveillance and reconnaissance]."

San Jose-based Quantum ­3D's systems are typically used with head-mounted or handheld displays rather than voice interfaces. Input is performed through various means, including buttons, joysticks, touch screens and programmable controllers similar to those used in video games.

But most wearables use speech for both input and output. The voice software is "trained" to recognize a specific user, and the applications generally have vocabularies of fewer than 100 words. Typically, vendors offer several language interfaces, and multiple languages are often used inside the same warehouse. The units can last a full shift on a single battery charge, thanks to power optimization, hot-swappable batteries and the absence of a display screen. The units are ruggedized for the wear and tear of nondesktop life.

With wearables, "new employees in a warehouse can be got up to speed in a day, since they are continually getting instructions on what to do, as opposed to being trained for a week by following another picker around," says Scott Yetter, CEO of Voxware, a wearable computer vendor in Lawrenceville, New Jersey.

Yetter says that users of wearable computers can typically expect a reduction of 30% to 50% in their error rates. And that performance may by itself justify adoption of the system, because shipping the wrong product can be expensive. Productivity can increase 10% to 20%, since the pickers don't have to continually put down and pick up their clipboards, he adds.