A microsphere-structure flexible pressure sensor for monitoring keyboard typing behavior

Abstract

Keyboard input is a commonplace activity in daily work that greatly enhances office efficiency. However, wrong typing posture over a prolonged period can lead to tenosynovitis or even tenosynovial cysts. Flexible sensors are widely utilized in human motion detection, but further in-depth research is required to identify typing posture accurately. Herein, a triboelectric-based pressure sensor with a microsphere structure was developed in this paper. Microsphere structures were fabricated onto the surface of silica gel (SG) to increase the friction coefficient and enhance the sensor’s performance. To establish a tight fit between the sensor and the skin, a flexible and adhesive polyacrylamide hydrogel was prepared. The microsphere-structured sensor holds a sensitivity of 0.903 V/N and a frequency response range of 0–20 Hz. It also exhibits good mechanical stability up to 18,000 cycles. It can monitor not only large-scale movements but also subtle muscle activities. By affixing the sensor to the skin surface on the wrist, it can effectively capture the motion signals generated during an individual’s typing and ascertain the correctness of the typing posture. This work provides technical support for the early prevention of tenosynovitis and tenosynovial cysts and exhibits promising applications in the long-term correction of typing posture.