A waterproof, high-output and airtight-cavity-airbag structural insole based on a TENG is presented to harvest human energy for driving wearable electronics.

Flexible pressure sensors with the capability of monitoring human vital signs show broad application prospects in personalized healthcare. In this work, a hair-based flexible pressure sensor (HBPS) consisting of lost hair and polymer films was proposed for the continuous monitoring of the human epidermal arterial pulse waveform. A macroscale mesh structure formed by lost hair provides a simplified spacer that endows the triboelectric-based flexible pressure sensor with sufficient contact–separation space. Based on this mesh structure design, the hair-based flexible pressure sensor can respond to the slight pressure change caused by an object with 5 mg weight and hold a stable output voltage under 1–30 Hz external pressure excitation. Additionally, the hair-based flexible pressure sensor showed great sensitivity (0.9 V/kPa) and decent stability after 4500 cycles of operation. Given these compelling features, the HBPS can successfully measure the human epidermal arterial pulses with obvious details at different arteries. The proposed HBPS can also be used to monitor the pulse signals of different subjects. Furthermore, the three different pulse wave transmission time (PTT) values (PTT-foot, PTT-middle, and PTT-peak) can be obtained by simultaneously monitoring human pulse and electrocardiogram signals, which has enormous application potential for assessing cardiovascular system health.

Triboelectric interfaces have already been extensively researched in the area of human-machine interaction owing to their self-sustainability, low cost, easy manufacturing, and diverse configurations. However, some limitations (e.g., a large number of electrodes, multiple lines, and chunks) observed in previous works hinder the further development of human—machine interaction applications. Herein, a triboelectric encoding interface is proposed by designing the reverse polarity of the tribo-layers to encode the triboelectric output signals. Owing to the inversion of the tribo-layers and the number of strip electrodes, this encoding method can realize multipurpose interactive commands by using fewer electrodes and a simple structure only in one macroscopic triboelectric device, which greatly reduces the size of the device as well as the influence of external factors on the coded signal output. As a demonstration, a ring with the patterned triboelectric interface (15 mm × 20 mm) achieves slide presentation and remote electric device control. In addition, the triboelectric sensor has good sensitivity (1.55 V/N) and durability (> 30,000 cycles). This new encoding mode shows the high applicability of the operation mode in diversified interactive applications, which provides more design strategies for intelligent control.