Low-cost wearable electronics

Fabric researchers at the Wilson College of Textiles at North Carolina State University have created a technique for embroidering power-generating yarns onto fabric. This process allows researchers to embed a self-powered, numerical touchpad and movement sensors into clothing to offer a low-cost, scalable potential method for making wearable devices.

“Our technique uses embroidery, which is pretty simple—you can stitch our yarns directly on the fabric,” says Rong Yin, assistant professor of textile engineering, chemistry and science at North Carolina State University. “During fabric production, you don’t need to consider anything about wearable devices,” says Yin. “You can integrate the power-generating yarns after the clothing item has been made.”

The embroidery yarn uses five commercially available copper wires twisted together with a thin polyurethane coating. This is then stitched onto cotton fabric with PTFE.

“You can embroider our yarns onto clothes, and when you move, it generates an electrical signal, and those signals can be used as a sensor,” Yin says. “When we put the embroidery in a shoe, if you are running, it generates a higher voltage than if you were just walking. When we stitch numbers onto fabric and press them, it generates a different voltage for each number. It could be used as an interface.”