3D Printed Sensors for Wearable Electronics and Smart Gesture Recognition

Modern materials with unique structures and functions are inspired by nature. However, nature's craftsmanship is beyond the reach of traditional handmade techniques. 3D printing technology creates the possibility of creating bionic structures. In this study, inspired by the ability of spiders to sense the capture of prey through the vibration of their webs, a spider-web-like, highly sensitive hydrogel sensor is designed and printed. The hydrogel is made of eco-friendly green polyvinyl alcohol cross-linked with microcrystalline cellulose. Surprisingly, the 3D-printed hydrogel sensor can manipulate the sensitivity by changing the angle and strain range of the structure. Accordingly, the Gauge factor (GF) of the 3D-printed hydrogel ( θ = 60°) is up to 58.23, which is 23.9 times higher than that of the non-3D-printed hydrogel sensor (GF = 2.43). The GF of the 3D-printed hydrogel at other angles still remained high at 24.74 ( θ = 90°) and 12.31 ( θ = 120°), respectively. It can be seen that the 3D-printed hydrogel sensor has advanced performance. In addition, an intelligent gesture recognition system for human–computer interaction is constructed using 3D-printed hydrogel sensors, which offers potential prospects for helping people communicate.