An experimental new wearable could allow people such as stroke victims to communicate via subtle hand movements. The device takes the form of a relatively thin patch that is temporarily adhered to the skin on the back of the wrist.
Currently in prototype form, the gadget is being developed by Chinese scientists from Beijing Normal University, Sun Yat-sen University and Guilin University of Electronic Technology. It's mainly intended for use by people who are unable to speak, or to move their hands enough to use a keyboard or touchscreen.
Although hand-movement-sensing communicative gloves are already in the works, the new device detects much smaller movements, plus it leaves the hand freer to feel surfaces and otherwise interact with the wearer's surroundings.
It features a soft, flexible, biocompatible polydimethylsiloxane (PDMS) silicone base material, embedded in which are multiple fiber Bragg gratings (FBGs).
In a nutshell, an FBG is a reflector that is etched into a short length of optical fiber, which reflects certain wavelengths of light while allowing all others to proceed. As that fiber bends with the hand/wrist, the characteristics of the light that has passed through it change accordingly. Therefore, by establishing which hand movements affect the light in which ways, it's possible to subsequently tell what the hand is doing based solely on the behavior of the light.
"The real magic comes from the combination of the PDMS with FBGs," said Guilin University's Dr. Chuanxin Teng. "We found that using a thicker PDMS patch caused a more pronounced wavelength shift. Leveraging this sensitivity-enhancing effect of PDMS allows these optical sensors to detect even the slightest bend of a finger or twist of a wrist."
Such movements allowed test subjects to transmit commands and words in Morse code, after the device had quickly been calibrated to each person. The scientists are now working on miniaturizing the technology, boosting its durability, and optimizing its ability to wirelessly communicate with nearby smartphones. They're also looking into other uses for the patch.
"Beyond detecting movement, these adaptable sensors could be tailored for applications such as monitoring other health indicators like respiratory or heart rate by detecting subtle body movements," said Beijing Normal University's Assoc. Prof. Rui Min. "They could also be useful for athletes or fitness enthusiasts to monitor and improve their form or technique in real time or be integrated into gaming systems for more immersive and interactive experiences."
A paper on the research was recently published in the journal Biomedical Optics Express.
Source: Optica
