Wheel Power This image show an experimental test of piezoelectric nanowires that harness a hamster's wheel-turning energy into usable power. Fifty nanowires bundled together would be about the width of a single human hair. Discovery News Video
by Eric Bland, Discovery News
March 9, 2009 -- Hamsters can seemingly run forever inside their little wheels, and scientists from Georgia Tech are finally helping them get somewhere.
To harness hamster power, the scientists sewed electricity-generating threads one-fiftieth the width of a human hair into a yellow jacket worn by the hamsters as they ran. A human-sized jacket, capable of powering an iPod, could be ready in as little as three years.
"This can totally be scaled up," said Zhong Lin 'ZL' Wang, who co-authored a paper describing the research in this month's issue of Nano Letters. "This is just the first step. The idea is that we would harvest energy from any body movement, from walking, breathing, from any kind of vibration."
The jacket's tiny threads are really nanowires made of zinc oxide, the same white stuff smeared on the noses of lifeguards. When the nanowires are flexed, a small amount of electricity is generated.
A zinc oxide wire is one micron wide and 50 microns long. One wire sewed into the hamster jacket generates about 0.1 volts of electricity. According to Wang, this is the world's first example of an animal producing power using nanopiezoelectrics -- a field of research that aims to capture tiny amounts of energy from movement and vibration, and transform it into usable power.
A bundle of 50 nanowires one human hair wide would be able to generate more than enough energy to power sensors that could monitor temperature and other conditions.
Powering an iPod would require hundreds of nanowires, covering an area equivalent to several human hairs. A thousand hamsters wearing the current jacket could charge a cell phone. Campbell's Dwarf, one of the hamster test runners, was able to generate one-twentieth the power of an AA battery.
But don't rush out to the pet store for your own personal rodent power plant yet. Wang estimates that it will be at least three years before his team can create enough nanowires to create a piece of fabric capable of powering a personal electric device.
"It's not something that you can immediately use for specific applications," said Min-Feng Yu, a scientist at the University of Illinois who creates piezoelectric nanowires but was not involved in the Georgia Tech study. "It's the combination of voltage and current."
Getting large voltages out of the piezoelectric nanowires is only half the battle. Scientists also have to generate large, continuous currents to directly power electrical devices. A battery could store any power generated from the tiny wires when they aren't moving but would complicate the current set up, adding weight and complexity.
Linking a shirt to an iPod is just one possible application for the new technology, said Wang. A whole range of tiny biological or environmental sensors could be created using the technology as a power source.
"Current power sources are large or antiquated to be implanted into biological systems and don't take advantage of the low power consumption," said Wang. "But if you can harvest that energy from the environment or body movement, you can have a self-powered nano system, providing not only energy for itself but for other devices as well."