The next advancement in wearable technology is a fabric armband with a touchpad. Researchers report in ACS Nano that they have developed a method to make playing video games, drawing cartoons, and signing documents easier. Their silk armband proof-of-concept converts a person's forearm into a keyboard or sketchpad. The three-layer, touch-responsive material translates what a user sketches or types into computer pictures.
Computer trackpads and electronic signature capture devices appear to be ubiquitous, but they are not common in wearables. Researchers have proposed constructing flexible touch-responsive panels out of clear, electrically conductive hydrogels, but these materials are sticky, making writing on them difficult and uncomfortable for the skin. As a result, Xueji Zhang, Lijun Qu, Mingwei Tian, and coworkers sought to combine a comparable hydrogel into a comfortable fabric sleeve for drawing or playing computer games.
A pressure-sensitive hydrogel was sandwiched between layers of knit silk by the researchers. To make the fabric electrically conductive, the top piece was covered in graphene nanosheets. When a finger slid over the sensing panel, it produced a pressure-responsive pad with real-time, rapid sensing when connected to electrodes and a data collection system.
The device was then embedded in an arm-length silk sleeve with a touch-sensitive region on the forearm. In experiments, a user used an armband to control the movement of blocks in a computer game and to draw vivid cartoons in a computer drawing application.
According to the researchers, this wearable touch panel proof-of-concept could inspire the next generation of flexible keyboards and wearable sketchpads.
The research was funded by the National Key Research and Development Program, Taishan Scholar Program of Shandong Province in China, Shandong Province Key Research and Development Plan, Shandong Provincial Universities Youth Innovation Technology Plan Team, National Natural Science Foundation of China, Natural Science Foundation of Shandong Province of China, and the Opening Fund of China National Textile and Apparel Council Key Laboratory of Flexible Devices for Intelligent Textile and Apparel at Soochow University.
Xu, R., et al. (2023). Skin-Friendly and Wearable Iontronic Touch Panel for Virtual-Real Handwriting Interaction. ACS Nano. doi.org/10.1021/acsnano.2c12612.