A paper-thin, flexible device created at Michigan State University not only can generate energy from human motion, it can act as a loudspeaker and microphone as well, nanotechnology researchers report today in Nature Communications

The audio breakthrough could eventually lead to such consumer products as a foldable loudspeaker, a voice-activated security patch for computers and even a talking newspaper.

In late 2016, Nelson Sepulveda, associate professor of electrical and computer engineering, and his team successfully demonstrated their sheet-like device – known as a ferroelectret nanogenerator, or FENG – by using it to power a keyboard, LED lights and an LCD touch-screen. That process worked with a finger swipe or a light pressing motion to activate the devices – converting mechanical energy to electrical energy.

The current breakthrough extends the FENG’s usability. The researchers discovered the high-tech material can act as a microphone (by capturing the vibrations from sound, or mechanical energy, and converting it to electrical energy) as well as a loudspeaker (by operating the opposite way: converting electrical energy to mechanical energy).

Wei Li, an MSU engineering researcher and lead author of the paper in Nature Communications, said other potential applications of the FENG include noise-cancelling sheeting and a health-monitoring wristband that is voice-protected.

The research is funded by the National Science Foundation. Other co-authors are David Torres, Ramon Diaz and Chuan Wang from MSU, and Zhengjun Wang, Changsheng Wu and Zhong Lin Wang from the Georgia Institute of Technology.

See more at: http://msutoday.msu.edu/news/2017/how-scientists-turned-a-flag-into-a-loudspeaker/