Electrical engineer Jenshan Lin took the technology that tracks enemy bombers and hurricanes and employed it to detect another danger -- when babies stop breathing.

December 3, 2008

In a high-tech twist on the remote devices that allow parents to listen
to or watch their baby from afar, University of Florida engineering
researchers have built a prototype baby monitor that focuses on a baby's
breathing. If his or her chest stops moving, the crib-mounted monitor
detects the problem and sends an alarm to a portable unit kept by the
parents.

"It's a step beyond just watching the baby through a video link or
hearing it cry," said Jenshan Lin, a UF professor of electrical and
computer engineering and the principal investigator of the Doppler radar
technology used in the monitor.

A paper on the system, which works by using Doppler radar to remotely
scan the in-and-out movement of the baby's chest due to respiration,
will appear in the February issue of IEEE Microwave Magazine.

Parents buy millions of baby monitors each year in the U.S., but most
transmit only sounds or video images of the baby -- both useful, but
only if a parent is listening or watching. Some recently available
monitors also monitor babies' movements and breathing, but Lin said he
is not aware of any on the market that use wireless technology.

UF engineering students Changzhi Li, Julie Cummings, Jeffrey Lam, Eric
Graves and Stephanie Jimenez designed the monitor.

The students did the work as part of the College of Engineering's
Integrated Product and Process Design Program, which allows senior-level
undergraduates to participate in yearlong design projects of new
products or processes. The student team's goal: to use Lin's radar
technology, first developed three years ago and under continuous
refinement since, in a useful product with the potential to be licensed
to a company.

The students produced a small-book-sized device that attaches to the
crib just like a standard monitor. They also designed a remote station
with red, blue, green and yellow lights, variously indicating the status
of the baby's vital signs, the battery life of the station and
confirming the station's wireless connection to the crib monitor. The
station emits a loud alarm
and flashes a red light when the monitor detects that the baby's
breathing activity has fallen below a preset threshold, or that he or
she has stopped breathing.

Future versions could also detect heartbeat, using a higher frequency
signal, Lin said.

"It's the same Doppler radar that police use to catch speeders, but in
our case, we don't measure constant speed, but rather back-and-forth
motion -- sort of like vibration," Lin said. "That's the fundamental
principle of this technology."

The crib monitor's signals are very low power and not harmful to the
baby or parents, Lin added. While a standard cell phone emits about one
watt of power, the Doppler radar emits just one ten-thousandth of a watt
of power, he said.

Tom Weller, associate dean for research at the University of South
Florida College of Engineering, said the baby monitor is a good example
of how research and education can come together in a useful product.

"This miniaturized monitor is an example of solid microwave engineering
coupled with great innovation, and something with the potential for a
very broad societal impact," Weller said in an e-mail. "It is especially
noteworthy that Dr. Lin transferred his research output into the very
capable hands of creative undergraduate students."

Lin is also pursuing other applications for his technology. His
best-realized idea so far: a search-and-rescue robot equipped with the
Doppler system to determine the presence of living people in structures
damaged by earthquakes or explosions. Lin said the system, so far tested
in a small working prototype robot, could complement robotic video
systems because it requires less power to operate and has greater range.
The robot was developed by student Gabriel Reyes as his research project
in the University Scholars Program. 

"Or the military could use it to find enemy soldiers," Lin said, noting
that the Doppler radar easily penetrates walls or other structural
components.

Lin has also reduced the size of the electronics in his system so that
they fit on a fruit fly-sized microchip, potentially enabling the remote
monitor to be used in cell phones. That could turn the phones into
portable life-sign detectors useful, for example, for friends and family
who wish to keep tabs on elderly relatives living alone, he said.

Li, who based his dissertation on the research, was awarded a graduate
fellowship from the IEEE Microwave Theory and Techniques Society for his
work.