Stories tagged piezoelectric effect

Green June Beetles (before cyber-enhancement)
Green June Beetles (before cyber-enhancement)Courtesy Wikimedia Commons
Unmanned aerial vehicles (UAVs) are commonly used in military operations. Micro air vehicles (MAVs) are a subcategory of UAVs that are currently in development and can be as small as 15 centimeters (~ 5.9 inches); their anticipated uses include search-and-rescue, surveillance, detection of explosives, and monitoring of hazardous environments.

Two researchers from the University of Michigan researchers had an idea: instead of building UAVs the size of an insect, why not use the insects themselves? Professor Khalil Najafi and doctoral student Erkan Aktakka engineered a piezoelectric generator that converted the kinetic energy from the wing movements of a Green June Beetle into electricity (45 µW per insect). Their research was recently published in the paper, "Energy scavenging from insect flight," which appeared in the Journal of Micromechanics and Microengineering.Cyborg Beetle: Through a device invented at the University of Michigan, an insect's wing movements can potentially generate enough electricity to power small devices such as a camera, microphone, or gas sensor.
Cyborg Beetle: Through a device invented at the University of Michigan, an insect's wing movements can potentially generate enough electricity to power small devices such as a camera, microphone, or gas sensor.Courtesy Erkan Aktakka

This research was funded by the Hybrid Insect Micro Electromechanical Systems (HI-MEMS) program of the Defense Advanced Research Projects Agency.

University News Release: Insect cyborgs may become first responders, search and monitor hazardous environs

Feb
15
2008

Rubs you the right way: This microscope image shows the fibers that are part of the microfiber nanogenerator. The top one is coated with gold. When rubbed together, the wires create a low amount of electricity. (Image courtesy Zhong Lin Wang and Xudong Wang).
Rubs you the right way: This microscope image shows the fibers that are part of the microfiber nanogenerator. The top one is coated with gold. When rubbed together, the wires create a low amount of electricity. (Image courtesy Zhong Lin Wang and Xudong Wang).Courtesy Georgia Tech
This sounds like some bad leftover from the disco era -- remember that cheesy movie "Electric Horseman? But scientists at Georgia Tech have developed an electricity-generating fabric that we might someday soon be wearing.

The new cloth would create enough electricity through normal living activities to power up an iPod or similar electrical device. To be more specific, one meter of the fabric would create 80 milliwatts of electricity.

How can this happen?

The fabric has ultra-thin wires woven into it. Wires going one direction are coated with zinc oxide while wires aligned in the other direction are treated with gold. When rubbed together through everyday movement of the wearer, they create electricity that can be fed into a current. In scientific terms, this technology is known as the piezoelectric effect.

Powerline: This schematic shows how pairs of fibers would generate electrical current.
Powerline: This schematic shows how pairs of fibers would generate electrical current.Courtesy Georgia Tech
The wires are only 50 nanometers in thickness, or about 1,800 times thinner than a strand of your hair. Because of this microscopic size, designers figure that the wires won’t create any substantial extra weight to clothes made of the fabric. Also, designers believe they’ll be able to use other cheaper metals to get the same electricity-generating effect.

Along with being used in clothes to generate small amounts of electricity, researchers can see other applications for the technology. The fibers could also be woven into curtains, tents or other structures to capture energy from wind motion, sound vibration or other mechanical energy.

There is one huge drawback. So far developers haven’t figured out how to make the fabric waterproof. That’s a major consideration when you realize that owners of the clothes at some point will want to wash it or wear it while it’s raining.

Want all the juicy details of this latest technology? Here’s a link to Georgia Tech’s full report on piezoelectric fabrics.