Researchers develop skin-friendly, wearable touch panel

Researchers say they have devised a way to make playing video games, sketching cartoons and signing documents easier by developing a fabric armband that’s actually a touch pad. The proof-of-concept silk armband turns a person’s forearm into a keyboard or sketchpad. The three-layer, touch-responsive material interprets what a user draws or types and converts it into images on a computer.

Computer trackpads and electronic signature-capture devices are ubiquitous but are not used widely in wearables. Researchers have suggested making flexible touch-responsive panels from clear, electrically conductive hydrogels, but these substances are sticky, making them hard to write on and irritating to the skin. Researchers Xueji Zhang, Lijun Qu, Mingwei Tian and colleagues wanted to incorporate a similar hydrogel into a comfortable fabric sleeve for drawing or playing games on a computer.

The researchers sandwiched a pressure-sensitive hydrogel between layers of knit silk. The top piece was coated in graphene nanosheets to make the fabric electrically conductive. Attaching the sensing panel to electrodes and a data collection system produced a pressure-responsive pad with real-time, rapid sensing when a finger slid over it, writing numbers and letters.

The device was then incorporated into an arm-length silk sleeve with a touch-responsive area on the forearm. In experiments, a user controlled the direction of blocks in a computer game and sketched colourful cartoons in a computer drawing program from the armband. The researchers believe the proof-of-concept wearable touch panel could inspire the next generation of flexible keyboards and wearable sketchpads.

Image caption: When a person draws a panda on this touch-responsive armband that’s worn on their forearm (bottom right of photo), it shows up on a computer. Image credit: Adapted from ACS Nano 2023, DOI: 10.1021/acsnano.2c12612.