| Posted: Jan 10, 2014 |
|
Using micro-windmills to recharge cell
phones |
| (Nanowerk News) A UT Arlington research associate
and electrical engineering professor have 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 cell 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. |
 |
| A
micro-windmill is pictured on the face of a penny. |
| "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 with the UT Arlington team several times in 2013
to discuss 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 Ph.D
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 sizes, 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. |