I first read about Kohei Hayamizu in 2007 while doing some research for a lesson on renewable energy. I was searching for a Japanese inventor with a unique vision for the future of alternative energy, someone who might spark the imagination of my Japanese high school students. When I came across an article on Hayamizu and his “power-generating floor”, I knew I had found my inventor.
Hayamizu’s vision started to take shape when he was an elementary school student. Listening to a loudspeaker, he began to wonder about the process of sound production from electric current. He thought that if sound can be made using electricity, shouldn’t the process work in reverse? Hayamizu went on to study at a university in Kanagawa Prefecture. According to Eriko Arita of the Japan Times, he based his dissertation on the idea of using sound (or vibration) to create electricity.
By 2007, Hayamizu, now founder and CEO of Soundpower Corporation, had produced a working prototype of his “power-generating floor”. The device uses flat plates of piezoelectric materials (discussed here & on Wikipedia) to create electricity from vibrations. In 2007, the device was imbedded in a square meter of concrete outside of Shibuya Station in Tokyo. With an estimated 2 million people passing through on weekdays, Shibuya is one of the busiest railway stations in the world –a perfect location for taking advantage of the footfalls of people to create electricity.
When I presented this information to my classes, the implications of Hayamizu’s work were not lost on my students. Without prompting, my 3rd graders (equivalent to high school seniors in the U.S.) immediately began to think of other applications for this technology. One of the ideas that came out of our brainstorming session (and one that incidentally was already in development at Soundpower at the time) was a device that would charge your cell phone or MP3 player as you walked.
Since it’s debut, the “power-generating floor” has garnered much attention in the renewable energy industry in Japan. The technology has been refined, and is being deployed in business offices and on busy roadways and bridges to augment power demands for lighting. The plates are even available for rent from the Soundpower Corporation website (in Japanese). A number of other products are in the works, including a 2010 joint venture with NEC to create a battery-less TV remote control which charges with each press of a button.
Hayamizu’s ultimate dream of converting sound to electricity is under development as well. One of the product listings on Soundpower’s website provides details of an LED device that lights up when exposed to sound vibrations. Though it may be a number of years before we see such technology on the market, the applications are endless. Think of the roar of a jet landing at SFO or the rumble of the crowd at AT&T Park… to visionaries like Hayamizu, these are examples of power going to waste.