Printed newspapers may be going out of style, but what if you could have a flexible electronic paper that reads headlines or the weather report and skips to the sports section on voice command?
Researchers at Michigan State University have developed a sheet-like device — known as a ferroelectret nanogenerator, or FENG — that acts as a loudspeaker and microphone and can generate energy from human motion, such as swiping a finger across a screen.
“It’s a device that you can roll up and put in your pocket and then get somewhere and unroll and put it on a screen or a window or any platform and use it as a both a microphone and loudspeaker,” said Nelson Sepulveda, an associate professor of electrical and computer engineering at Michigan State University, and the primary investigator of the new study published online May 16 in the journal Nature Communications.
Last December, Sepulveda and his team detailed the main component of this device, the FENG, in the journal Nano Energy. At that time, the researchers showed off the thin film’s ability to generate power from motion. It had the added benefit of being able to exponentially increase its voltage every time it was folded, the scientists said.
This latest research builds on that capability. The device now works as a microphone, picking up vibrations in the air (in other words, sound waves) and converting them into electric energy. It also turns electrical signals, from a computer file, for example, into vibrations that people can hear as sound.
In a couple of different demonstrations, the scientists showed how it could work. They embedded the FENG into the university’s Spartan flag and then played the school’s fight song through it. They also showed it could work as part of a voice-recognition system to authenticate access to a computer.
“The fidelity and the quality of the sound recognition is high enough to recognize the pitches and the frequency components of an individual’s voice.”