New wearable sensor in the shape of a braided cord (Kumihimo)

A new piezoelectric sensor was developed in the shape of a traditional Japanese braided cord known as a Kumihimo by weaving piezoelectric poly-l-lactic acid (PLLA) fibers (piezoelectric PLLA braided cord). We found that the piezoelectric PLLA braided cord tied in various decorative knots, and worn as an accessory such as a choker or necklace, can detect pulse waves, swallowing, and coughing in a systematic way in one's daily life. To demonstrate this, we developed a system for measuring pulse waves with a Wi-Fi communication system using a piezoelectric PLLA braided cord with decorative knots.