Tag Archives: Wearable

Electronic textiles could turn clothes into wearable electronics

Smartwatches and wristbands have come a long way, but what if you could integrate electronic displays directly into clothing? Researchers in China explored this concept in a new study where they described electronic textiles that can be turned into flexible, breathable, and durable displays.

The ultimate wearable electronics: your clothes

Weaving solid-state display materials into clothing is not only cumbersome and clunky, it’s just impractical. Although there are paper-thin, flexible micro-LED displays out there, they simply can’t withstand the kind of deformation that is expected when fabrics are worn and washed.

Huisheng Peng and colleagues at Fudan University in Shanghai, China, looked at this problem and thought of an obvious solution: just turn the clothing’s textiles into electronic displays.

To this aim, the researchers produced a prototype of a display fabric measuring 6 meters in length and 25 centimeters in width. The display fabric can be integrated with another layer of touch-sensitive fabric for the user interface, as well as a fabric power supply. In this case, the power is harvested from solar energy.

A multicolor display textile exhibiting softness and stability under distortion. Credit: Huisheng Peng.

But first, Peng’s team had to overcome a number of technical challenges. To produce illumination, the researchers weaved conductive weft and luminescent warp fibers while being careful to have a stable interface between these two fiber electrodes with an additional transparent and elastic composite fiber.

Another problem is that the thin active layer needs to be coated uniformly, a challenge that was surmounted with the help of scraping micro-pinholes. “We had thus achieved a continuous and large-scale production of such display textiles,” Peng said.

“Integrating displays into textiles offers exciting opportunities for smart electronic textiles – the ultimate form of wearables poised to change the way we interact with electronic devices, but thin-film displays could not meet the application requirements,” Peng told ZME Science.

“Display textiles thus become necessary to serve to bridge human-machine interactions, offering, for instance, a real-time communication tool for individuals with voice or speech disorders,” the researcher added.

During tests, the researchers demonstrated various applications, such as turning the fabric into a navigation tool that displays an interactive map or as a smartwatch-like tool that sends or displays messages via a Bluetooth connection with a smartphone.

After 1,000 cycles of bending, stretching, and pressing, the electroluminescent units remained stable suggesting that the display fabric could perform well in a real-life use case when constant deformation is expected.

Application scenarios for display textile as real-time location and message communication. Credit: Huisheng Peng.

This is why Peng is confident that these fabrics can come to market soon. He already has opened collaborations with some companies involved in the auto, wearable electronics, and smart clothing industries. “I think the display textiles can be widely used for real applications in this year,” the researcher told me in an email.

Next, the researchers plan to scale up the resolution of their display textile and the intensity of the illumination, while keeping costs low.

“As a new technology in displaying, they may change the way we live in many directions,” Peng concluded.

Paper-thin speaker.

Paper-thin device turns touch into electricity, flags into loudspeakers, bracelets into microphones

Michigan State University engineers have put together a flexible, paper-thin transducer — a device which can turn physical motion into electrical energy and vice-versa. The material could be used to create a whole new range of electronics powered from motion, as well as ultra-thin microphones and loudspeakers.

Paper-thin speaker.

Nelson Sepulveda and the paper-thin speaker.
Image credits Michigan State University.

Harry Potter may have had animated newspapers but you know what Hogwarts never had? Newspaper boomboxes. So I guess it’s score one for the muggles, since we’re about to get just that. Along with newspaper microphones, or anything else that’s really thin and works either as a sound recording or replay device. Our imagination’s the limit.

Fold-a-speaker

It’s all thanks to a team of nanotech engineers from Michigan State University, who designed and produced a prototype ultra-thin transducer. The device is fully flexible and foldable, can easily be scaled up and is bidirectional — meaning it can convert mechanical energy to electrical energy and electrical energy to mechanical energy.

The device’s fabrication process starts with a silicone wafer with several thin layers or sheets of environmentally friendly substances including silver, polyimide, and polypropylene ferroelectret added over it. Ions (which are charged particles) are added onto each individual layer so that they produce an electrical current when compressed.

Known as a ferroelectret nanogenerator (abbreviated FENG), it was first showcased in late 2016 as a sheet which could turn users’ touch into energy to power a keyboard, LED lights and an LCD touch-screen.

Since then, the FENG got some new tricks. The team discovered that in addition to its touch-to-energy transformation ability, the material can be used as a microphone — by turning the mechanical energy of sound into electrical energy — and as a loudspeaker — by doing the reverse.

“Every technology starts with a breakthrough and this is a breakthrough for this particular technology,” said Nelson Sepulveda, MSU associate professor of electrical and computer engineering and primary investigator of the federally funded project.

“This is the first transducer that is ultrathin, flexible, scalable and bidirectional, meaning it can convert mechanical energy to electrical energy and electrical energy to mechanical energy.”

Multiple uses

As a proof-of-concept for sound recording, the team developed a FENG security patch which uses voice recognition software to unlock a computer. Tests revealed that the patch can pick up on voices with a high fidelity, being sensitive enough to capture several frequency channels in the human voice.

To test how well the material would function as a loudspeaker, some FENG fabric was embedded into the faculty’s own Spartan flag. It was supplied with a signal from an iPad through an amplifier. The team reports that it reproduced the sound flawlessly, the flag itself becoming a loudspeaker. One day, you could be carrying speakers around everywhere, comfortably folded in your pocket until you need them. Or you could have a poster of FENG at home, ready to hook up to your PC, taking up virtually no desk space.

“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.”

“Or imagine a newspaper,” Sepulveda added, “where the sheets are microphones and loudspeakers. You could essentially have a voice-activated newspaper that talks back to you.”

Other applications could include a noise-canceling sheeting that also produces some energy in the bargain, or voice-operated wearable health-monitoring devices. The team says they’re also interested in developing in the “speaking and listening aspects” of the technology.

The full paper “Nanogenerator-based dual-functional and self-powered thin patch loudspeaker or microphone for flexible electronics” has been published in the journal Nature Communications.