Dilbert and Wearable Computers
Wearable Computer Architecture and
In the comic strip, Dilbert tells his dog, “I built a ring with a
tiny computer in it. It only displays one character at a time.” When
the dog scoffingly responds with, “Then what good is it?” Dilbert
says: “No time for chit-chat. I’m surfing the net.”
Although equipping a ring with a computer that displays only one
character at a time is comic-strip ludicrous, Siewiorek’s job has been
to find wearable computer applications that actually make sense in the
real world. As part of CSL’s Golden
Anniversary lecture series, Siewiorek talked about some of those
applications — the product of 10 years of research in Carnegie
For instance, Siewiorek brought along a Vu·Man 3, one of the
research group’s earliest wearable computers, dating back to 1994.
Vu·Man 3 consists of a small display monitor that is worn
on the head and connects to a dial and selection-buttons worn on the
waist. This wearable computer was designed for Marines as they
inspected amphibious tractors.
The Vu·Man 3 replaced a clipboard, freed up the Marine’s
hands, and made it possible for one person, rather than two, to do the
job. While wearing the computer, the Marine can squeeze beneath the
equipment, maneuver in tight spots, and inspect the 600 different
equipment items on the list.
As the Marine follows a checklist on the monitor (positioned just
below the eye), he or she turns the dial and pushes buttons to report
the equipment’s status. What’s more, this information automatically
translates into written requests for repair and equipment orders.
Under the old system, the hand-written checklist had to be keyed into
By making the entire process more efficient and by eliminating one
Marine in the task, the Vu·Man 3 reduced inspection time by
70 percent. According to Siewiorek, whenever they design a wearable
computer system, they look for repeated patterns “And once we find
repeated patterns, we’re pretty sure what we want to build,” he said.
Typically, their wearable computers are used to increase efficiency
for mobile workers in doing any of three tasks: following procedures,
issuing work orders, and interacting in real-time with other
“We’re trying to get the right information to the right person at
the right place at the right time in the right language at the right
level of abstraction,” Siewiorek said.
In designing wearable systems, he also noted, they pay close attention
to “two gold nuggets” — two key resources. The first is human
attention. People can focus their attention on only so many things,
so engineers need to make sure that the wearable computer doesn’t
overload the senses. This requires extensive testing with users.
According to Siewiorek, engineers have a tendency to create systems in
their own image, forgetting the needs of the user. But at Carnegie
Mellon, they live by the saying: “I am not the user.” As he put it,
“We have the user part of our design team. It’s user-centered
The other key resource that they must constantly keep in mind is
“Batteries rule the world, particularly in mobile devices,”
Siewiorek said. “People want 8, 10, or 24-hour shifts out of the
systems we build. But keep in mind that batteries have half the
density of dynamite. So you can’t cram too much more into batteries
if you want to feel safe when you’re walking around.
“Motorola was wise,” Siewiorek added. “When the first cell phones
came out, they were big bricks that provided only 15 minutes of air
time. But now you can get hours of airtime. That’s because they took