Flexible paper-thin material acts as mic and loudspeaker
Foldable loudspeakers, voice-activated security patches and talking newspapers are just some of the suggested applications for a paper-thin flexible device that acts as a loudspeaker and microphone.
The device, which can also generate energy from human motion, comes from nanotechnology researchers at Michigan State University and was reported in Nature Communications.
While the sheet-like device isn’t new – it was demonstrated in 2016 when it was used to power a keyboard, LED lights and an LCD touchscreen – researchers are excited about a breakthrough that adds audio capabilities.
The original device - developed by a team headed by Nelson Sepulveda, MSU associate professor of electrical and computer engineering - was known as a ferroelectret nanogenerator, but was soon dubbed FENG.
Now, researchers have worked out that the material can capture vibrations from sound or mechanical energy and convert it into electrical energy to act as a microphone. To demonstrate this capability they produced a security patch that uses voice recognition to allow access to a computer.
Of course, it made sense that the material could work the other way to act as a loudspeaker and researchers embedded FENG fabric into a flag. Music was sent from an iPad through an amplifier and into the flag, which reproduced the sound.
“The flag itself became the loudspeaker,” Sepulveda said in an article on the MSU website. “So we could use it in the future by taking traditional speakers, which are big, bulky and use a lot of power, and replacing them with this very flexible, thin, small device.”
[Source: Michigan State University]