A new breakthrough technology could enable engineers to
create hands-free, eye-controlled video games and medical systems, as well as solutions
for the disabled.
Introduced
at the recent Consumer Electronics Show (CES)
in Las Vegas,
the new technology is believed to be the first to allow video gamers to play
simply by moving their eyes.
Engineers
at National Instruments who created the new interface
said they employed technology similar to the kind already used in
electrocardiograms (ECGs). "We took a standard biomedical measurement method
and tried to find a non-standard application for it," noted Hunter Smith, an
applications engineer at National Instruments.
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Like an
electrocardiogram, the "eyes only" technology employs conventional electrodes,
which are placed on the face and forehead of the user. The system works by
sensing the small voltages that are generated in a person's face when they move
their eyes. Voltage signals are passed through the leads of the electrodes to a
single-board computer with a custom-designed daughter card. At the daughter
card, the signals are amplified by an
Analog
Devices AD8221 instrumentation amplifier and digitized by an AD7401
analog-to-digital converter (ADC). They are then sent for processing to a
National Instruments RIO Single-Board Computer featuring a
Freescale real-time processor and a
reconfigurable
Xilinx FPGA (field
programmable gate array) running
LabVIEW
software. There, the eye motions are converted to a series of digital commands
that can move on-screen characters through a video game.
National
Instruments engineers said that environmental noise is the biggest technical
challenge to building such a system. Because voltage signals from the eyes are
only about one-fifth as strong as those from the heart, the engineering team
needed to use a low-noise amplifier in the processing chain.
"It's a lot
easier to get a clear heart signal," said Chris Culver, a staff hardware
engineer and co-developer of the system. "Heart signals are very distinctive.
Every time we built a board I would hook it up to my heart to make sure it was
working."
At CES, National Instruments
engineers showed how the processed signals can be used in conjunction with a
video display. Users at the show were able to move arrows on the display merely
by shifting their eyes left or right, up or down.
Culver said that the technology
could be employed in video games and in medical applications that treat
amblyopia, or "lazy eye." There, children could use their eyes to move arrows
on a screen in exercises that treat lazy eye.
NI engineers are also exploring
other applications. They believe the technology could serve as a video aid to
those who have lost the use of their hands, or are dealing with other
disabilities. Culver said that one NI engineer also wrote an application for a
flight simulator game, in which gamers could use their eyes to fly a virtual airplane.
NI engineers said that LabVIEW
software was critical to enabling the engineering team to build the system. "We
had zero biomedical experience but we were able to put this together in a few
months," Smith said.
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