Handhelds gain space
Technology Research News
Although a keyhole is quite small, putting
your eye close to it lets you see a significant portion of a room. Being
able to move the keyhole around would widen the view.
A researcher at the University of California at Berkeley has rigged
up a device that turns the small screen of a handheld computer into a
movable keyhole. Rather than pressing scroll buttons to get to a position
in a document, a user simply moves the handheld computer.
The screen is a window onto a larger virtual document. To navigate
to the lower left corner of an on-screen map, a user would move the computer
in and to the left. "The handheld computer scrolls its display as you
move it, in order to maintain the illusion that you are viewing a small
part of a large, fixed workspace," said Ka-Ping Yee, researcher at the
University of California at Berkeley.
The illusion goes both ways, allowing input into the larger virtual
space as well. "You can interact with the workspace using [a] pen while
moving the screen around to see different parts of that space," said Yee.
The idea sprung from real-world frustration over the sluggishness
of small-screen navigation. "I was motivated by wanting to position the
view directly instead of having to wait for the view to scroll," Yee said.
Yee put the device together by hooking up a handheld computer
to tracking equipment. "I tried three different methods, and there are
probably many other ways that it could be done as well," said Yee.
The three proof-of-concept prototypes include a partially deconstructed
mechanical mouse and fishing line, which allows users to move the computer
freely through space; the innards of an optical mouse affixed to a handheld
computer, which requires that the handheld be moved only along a surface,
and an ultrasonic transmitter, which allows for free movement, but is
more sluggish than the other methods.
Key to making viable prototypes was getting the handheld screen
to update fast enough to maintain the illusion, said Yee. "I had to get
the [handheld] to update its screen quickly so that it would respond smoothly
while the screen was being moved," he said.
Yee tested the usability of the peephole computing concept by
having 24 participants perform several simple tasks using both a conventional
handheld computer and the peephole prototype. They browsed using one hand
to move the display around, and performed as well as the usual two-handed
method -- using one hand to hold the PDA and a pen to scroll the display,
said Yee. The subjects also found it easier to browse a map using the
one-handed peephole method, he said.
The subjects were also able to draw 32 percent faster using the
peephole prototype, and said they strongly preferred the method, said
Yee. Many of the participants made larger drawings when using the peephole
method even though the canvas sizes were the same; this suggests that
the participants felt less constrained using the peephole interface, according
And 17 of the participants naturally used both hands when drawing
with the peephole prototype, moving the handheld with one hand to be able
to make longer pen strokes with the other, according Yee.
Allowing the user's non-dominant hand to navigate by moving the
handheld computer enables the dominant hand to work beyond the spatial
boundary that ordinarily forces the user to stop and scroll, according
Yee also expanded the virtual peephole space into three dimensions
with applications that allow users to switch views by moving the handheld
device vertically. "This technique lets you manipulate information in
multiple planes at once, because you can also raise or lower the display,"
he said. "That enables you to organize information in some pretty interesting
new ways," he said.
A three-dimensional peephole calendar allows users to scan horizontally
to view events in the coming week and vertically to delve down to the
details of a particular time of day.
And adding a third dimension to the sketch pad made it possible
to have a clipboard plane where users can drag-and-drop items. Unlike
ordinary computer clipboards, the clipboard plane is viewable, which makes
it possible for users to place more than one item on it, and to keep things
organized, according to Yee. To help the user stay oriented, Yee gave
the planes different background colors.
The work extends the idea of a handheld view port onto a virtual
workspace conceived by University of Toronto researcher George Fitzmaurice
a decade ago, according to Yee. Fitzmaurice used a handheld color TV connected
to a desktop computer to produce the illusion that the TV was a palm computing
Yee added pen input to the concept and implemented it on a handheld
computer. "Fitzmaurice's work was mostly about just viewing the information.
I've taken it a little further by exploring how you can use both hands
together to interact with information in the virtual workspace," said
It is a very good idea, and there are some nice applications,
said Brad Myers, a senior research scientist at Carnegie Mellon University.
The next step toward making a practical implementation is replacing the
string and pulleys used to keep track of the handheld's position, according
The work addresses a modern-day screen-size paradox, said Robert
Jacob, an associate professor of computer science at Tufts University.
"As we move away from desktop computers, we see interfaces becoming both
smaller and bigger -- smaller for portability and personal use, bigger
for larger display surfaces and information spaces," he said. "This work
attempts to bridge that gap by providing a large virtual user interface
and work surface using a small physical device."
Yee's spatially-aware-display is aimed at generally improving
the mechanics of using PDAs. The idea is to decouple the size of a computer
from the size of the information space a person has to work with, said
"What I'm envisioning is a personal information space, where...
information like your address book and your calendar are associated with
the space around you," said Yee. "They would follow you wherever you go...
you could pull out your PDA and find your calendar always located on your
right, and your address book on your left," he said.
The concept can also be applied to mobile phones. Yee wrote an
application for his prototype that leverages the peephole concept to make
it easier to select items from a handheld screen using only one hand.
The one-handed selector program allows the user to move the handheld device
vertically in order to move a highlight bar up or down the screen, then
select an item by pressing a button.
The concept could also be applied to expert interfaces as a way
to make many layers of information easily accessible, said Yee.
The concept could be turned into a practical device within five
years, said Yee.
The research is scheduled for presentation at the ACM Conference
on Human Factors in Computing Systems in April, 2003 (CHI 2003) in Fort
Lauderdale. The research was funded by an IBM Ph.D. fellowship.
Timeline: 5 years
TRN Categories: Human-Computer Interaction
Story Type: News
Related Elements: Technical paper, "Peephole Displays: Pen
Interaction on Spatially Aware Handheld Computers," scheduled for presentation
at the Association for Computing Machinery's (ACM) Conference on Human
Factors in Computing Systems in April, 2003 (CHI 2003) in Fort Lauderdale.
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