Self-powered wearable touchpad composed of all commercial fabrics utilizing a crossline array of triboelectric generators

Abstract

In the internet of things (IoT) era, electronic textile (E-textile), which combines diverse functional parts on a fabric substrate, has attracted much attention. Among the various components for E-textile, the human-machine interface device is one of the most important. Here, a wearable fabric touchpad based on a triboelectric generator (TEG) is demonstrated. It is created only with inexpensive commercialized fabrics. Long string-shaped fabric TEGs act as the rows and columns of a crossline array, and each cross-point of a unit cell at each row and column constructs a unit pixel. The proposed touchpad accurately traces basic motions such as the vertical tapping and lateral dragging of a polytetrafluoroethylene (PTFE) stylus and generates corresponding output signals. Based on this capability, the proposed touchpad can be utilized for the handwriting of digits and for their recognition as well. Digits from 0 to 9 written on the touchpad are successfully classified by a pre-trained neural network with very high accuracy of 98%. This implies that the proposed wearable touchpad has immediate practicality. Considering its cost-effectiveness, compatibility with the textile industry, and its accurate operation, the proposed touchpad is a strong candidate for use in interface devices in the future E-textile industry.