AUT Arlington Research Associate and
Electrical Engineering Professor has designed a
micro-windmill that generates wind energy and may become
an innovative solution to cell phone batteries
constantly in need of recharging and home energy
generation where large windmills are not preferred.
Smitha Rao and J C Chiao designed and built the
device that is about 1.8 mm at its widest point. A
single grain of rice could hold about 10 of these tiny
windmills. Hundreds of the windmills could be embedded
in a sleeve for a cell phone. Wind, created by waving
the cell phone in air or holding it up to an open window
on a windy day, would generate the electricity that
could be collected by the cel phone's battery.
Rao's works in micro-robotic devices initially
heightened a Taiwanese company's interest in having Rao
and Chiao brainstorm over novel device designs and
applications for the company's unique fabrication
techniques, which are known in the semiconductor
industry for their reliability.
"The company was quite surprised with the
micro-windmill idea when we showed the demo video of
working devices," Rao said. "It was something completely
out of the blue for them and their investors."
Rao's designs blend origami concepts into
conventional wafer-scale semiconductor device layouts so
complex 3-D moveable mechanical structures can be
self-assembled from two-dimensional metal pieces
utilizing planar multilayer electroplating techniques
that have been optimized by WinMEMS Technologies Co.,
the Taiwanese fabrication foundry that took an initial
interest in Rao's work.
"The micro-windmills work well because the metal
alloy is flexible and Smitha's design follows minimalism
for functionality." Chiao said. WinMEMS became
interested in the micro-electro mechanical system
research and started a relationship with UT Arlington.
Company representatives visited the UT Arlington team
several times in 2013 to discuss the collaboration.
An agreement has been established for UT Arlington to
hold the intellectual properties while WinMEMS explores
the commercialization opportunities. UT Arlington has
applied for a provisional patent. Currently, WinMEMS has
been showcasing UT Arlington's works on its website and
in public presentations, which include the
micro-windmills, gears, inductors, pop-up switches, and
grippers. All of those parts are as tiny as a fraction
of the diameter of a human hair.
These inventions are essential to build micro-robots
that can be used as surgical tools, sensing machines to
explore disaster zones, or manufacturing tools to
assemble micro-machines.
"It's very gratifying to first be noticed by an
international company and second to work on something
like this where you can see immediately how it might be
used," said Rao, who earned her PhD in 2009 at UT
Arlington. "However, I think we've only scratched the
surface on how these micro-windmills might be used." The
micro windmills were tested successfully in September
2013 in Chiao's lab. The windmills operate under strong
artificial winds without any fracture in the material
because of the durable nickel alloy and smart
aerodynamic design.
"The problem most MEMS designers have is that
materials are too brittle," Rao said. "With the nickel
alloy, we don't have that same issue. They're very, very
durable."
The micro-windmills can be made in an array using the
batch processes. The fabrication cost of making one
device is the same as making hundreds or thousands on a
single wafer, which enables for mass production of very
inexpensive systems.
"Imagine that they can be cheaply made on the
surfaces of portable electronics," Chiao said, "so you
can place them on a sleeve for your smart phone. When
the phone is out of battery power, all you need to do is
to put on the sleeve, wave the phone in the air for a
few minutes and you can use the phone again."
Chiao said because of the small size, flat panels
with thousand of windmills could be made and mounted on
the walls of houses or building to harvest energy for
lighting, security or environmental sensing and wireless
communication. He added that it has been fulfilling to
see his former student succeed and help move innovation
toward the marketplace.
"To see a company recognize that and seek you out for
your expertise speaks volumes about what UT Arlington
means to the world," he said proudly. Source: Science
Daily
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