Light and easy to transport, they're generally useless unless held stationary. Wearable computers, PCs designed to be carried around as they're being used, might eventually cause us, or our children, to view as unbearably primitive those computers that now demand our seated attention.
The memory, hard drive, processor and power source of both Xybernaut (www.xybernaut.com) and Mentis (www.teltronics.com/is), two of several commercially available wearable computers, are housed in cases approximately 5 inches by 7 inches and designed to be worn comfortably on the user's belt. The ViA II PC (www.flexipc.com) weighs just over 2 pounds and is worn near the lower back, on a belt assembly.
To enter commands and text into these and other wearables, users either employ voice recognition software or type on modified keyboards. To promote mobility while computing, displays are often mounted on eyeglasses (glasses-mounted displays) or suspended in front of one eye from a device worn on the user's head (head-mounted displays).
Although wearable computers are shrinking in size even as they become more powerful, they're still too cumbersome and expensive -- starting at $5,000 for a unit with computing power equivalent to a $500 desktop PC -- for mass-market appeal.
Perhaps, much like cellular telephones, wearable computers will establish a foothold in a niche market from which refinements will elevate it into everyday practicability. Once relegated by their bulk and expense to the automobiles of salespersons and business executives, cell phones are now so inexpensive and small that they fit into the budgets and shirt pockets of millions around the world.
And, like the salespeople who first experimented with those once-unwieldy phones, several industries are beginning to explore the potential of wearables. The U.S. Customs Service recently tested a wearable computer system that allowed officers on the Arizona-Mexico border to quickly screen outbound traffic for stolen cars. Instead of writing down a license plate number and walking to a stationary terminal to query law enforcement databases, the officers spoke the number into a Xybernaut computer and received the database response on the screen of a head-mounted display.
SafetyPad (www.safetypad.com), another wearable computer configuration, allows emergency medical technicians to quickly transmit electronic documentation on patient encounters. Aircraft maker and defense contractor Boeing Co. has long been a leader in the development of wearable computers for maintenance and manufacturing applications. Soldiers in Bosnia even used wearables to translate between English and Serbo-Croatian.
And the interest in wearables might be spreading.
"I met an insurance company executive interested in using them to remotely transmit information and pictures from accident sites to claims adjusters," said Allen Revels, a software engineer at the University of Dayton Research Institute (UDRI).
But it appears that wearable computers will gain that all-important first foothold as a replacement for bulky, inefficient reference manuals and checklists used by technicians. Instead of constantly flipping pages with greasy fingers and looking back and forth from a manual to a machine, technicians using wearables see schematics, specifications and procedures through a glass- or head-mounted display as they perform the repair task.
"Maintenance personnel continuously climb in and out of engine bays and squeeze into tight spots," said Laurie Quill, a human factors psychologist at UDRI. "It's very inefficient for them to repeatedly come out to refer to a manual."
Revels, Quill and human factors psychologist David Kancler are members of UDRI's Human Factors Group (HFG), a team that specializes in optimizing the relationship between people and the equipment with which they work. Since 1993, they've studied the feasibility of wearable computers for military applications, focusing mainly on input and display devices.
HFG has performed this wearable computer research in conjunction with the U.S. Air Force, an organization nearly buried by technical manuals. The Air Force operates hundreds of models of aircraft, each with hundreds of systems and subsystems that are regularly tested, maintained and repaired using paper manuals. Wearables could replace not only the repair manuals required for these aircraft but also those needed for nearly every other mechanical or electronic device, from automobiles and radar systems to copiers and fax machines.
Along with these potential advantages, wearable computers bring many challenges. One of these is the federal government's policy of purchasing commercially available products whenever possible. Known as COTS for "commercial off-the-shelf," this policy is a reaction to the negative publicity the military received for purchasing common items from contractual suppliers at exorbitant prices.
The COTS policy often forces researchers involved with military projects to solve problems with commercially available products instead of creating new items.
For example, although voice recognition software is a popular input device for wearable computers, it presents several problems in military settings. Sounds other than the speaker's voice often confuse the software, and microphones used for voice input can filter out only consistent external noises. Aircraft repair crews, however, work in environments in which the noise level varies greatly and unpredictably, from the near silence of a hangar to the thunderous roar of jet engines.
Additionally, voice recognition software is adept at certain commands, such as "page up" or "save file," but cannot easily handle complex mouse movements such as moving the cursor diagonally across the screen.
Consequently, HFG researchers have tested other commercially available input devices as alternatives to voice recognition software. One of these is the GyroMouse, a cordless mouse that uses a gyroscope sensor to translate in-air hand movements into on-screen cursor movements, eliminating the need to roll the mouse on a flat surface.
But the GyroMouse requires users to move the mouse through the air with one hand instead of having both hands free for the repair task. So the researchers incorporated the GyroMouse into the head-mounted display of a wearable computer, allowing technicians to control the cursor with head movements.
Yet this head movement couldn't duplicate the click of a mouse button, and no commercially available software combines mouse-generated cursor movement and voice-generated mouse clicking.
To solve this problem within the constraints of COTS, researchers turned to another off-the-shelf product, Cyberlink (www.brainfingers.com/cyberlink.htm). Developed by Andrew Junker of Yellow Springs for quadriplegics, Cyberlink uses three sensors embedded in a headband to translate electromyographic impulses generated by facial muscle activity into mouse clicks.
Field tests eventually revealed that the program couldn't filter out involuntary facial muscle activity, such as that caused by strenuous repair tasks. These grimaces, therefore, resulted in an unacceptable amount of errant mouse-clicks.
The researchers now believe that a second type of speech recognition software, one that translates throat vibrations into mouse movements, might be a viable alternative. Unlike sound waves, such vibrations are not impeded by surrounding noises.
In addition to mandating off-the-shelf purchases, the government helps to put products on the shelf by funding the development of promising technology into commercial products. One such initiative, available only to businesses with fewer than 300 employees, is known as the Small Business Innovative Research program.
Under this program, HFG researchers are currently testing a glasses-mounted display created by The Technology Partnership (www.techpartnership.com) of Grosse Ile, Mich. This device employs mirrors to reflect an image projected by a miniaturized screen onto an eyeglass lens.
The screen, roughly the size of postage stamp, is mounted on the inside of the eyeglass temple, next to the hinge that joins the temple to the lenses. Facing inward, it's aimed at a small mirror mounted on the eyeglass nosepiece. This relay mirror angles towards the right lens, reflecting the image from the screen onto a silvered quarter-inch-wide section of the lens. Wearers focus the right eye slightly inward to see the image reflected onto this silvered area.
One factor still being studied by these researchers is the possibility of eye fatigue brought on by looking inward to see the image.
"That's certainly a factor," Kancler said. "One potential solution would be to move the silvered piece down and to the center of the lens. Looking down produces much less eye fatigue than looking inward."
This area demonstrates the importance of human factors research to the ultimate success of wearable computers. Packed with computing power and portability, wearable computers are nonetheless too awkward to gain acceptance. The research performed by UDRI and similar groups provides the practical refinements that could make wearables more attractive to both industrial and consumer markets.
Visit www.udri.udayton.edu to learn more about this and other projects under way at UDRI.