Ultra-flexible nanofiber-based multifunctional motion sensor

Microstructured capacitive sensor with broad detection range and long-term stability for human activity detection

“…With the increasing demand for artificial intelligence and the internet of things, the potential of flexible and wearable sensors in human-machine interaction, soft robots, and health monitoring applications have received great attention [1][2][3][4][5] . According to the sensing mechanism, the flexible sensors are divided into four types: resistive-type [6][7][8][9][10] , capacitive-type [11][12][13] , piezoelectrictype [14][15][16] , and triboelectric-type 5,17,18 . Among them, capacitive sensors have been intensively investigated owing to their characteristics of simple fabrication, good anti-interference, and excellent long-term stability [11][12][13]19 .…”

Wearable triboelectric sensors for biomedical monitoring and human-machine interface

“…Body movement monitoring plays an important role in daily life especially for sports training, medical diagnosis/rehabilitation, and security ( Cui et al., 2019 ; He et al., 2018a ; Lin et al., 2018 , 2019 ; Zhang et al., 2019b ; Zou et al., 2019 ). In these particular applications, the flexibility, stretch ability, and shape-adaptability of sensor are essential for keeping signals stable and device available ( Alam et al., 2020 ; An et al., 2018 ; Gogurla et al., 2019 ; Han et al., 2019 ; Liu et al., 2018 ; Ma et al., 2020 ; Sarkar et al., 2019 ). In this part, five examples based on different fabrications are reviewed: first, a flexible sensor assembled with serpentine-patterned electrodes and wavy-structured Kapton film for detecting the pressing and stretching force in human motions ( Yang et al., 2015b ); second, an environmentally friendly hydrogel-based tube-shaped TENG for sensing human motions ( Xu et al., 2017 ); third, a shape-adaptive sensor based on a rubber strap covered conductive liquid for biomechanical monitoring ( Yi et al., 2016 ); fourth, a textile-based TENG sensor for gait monitoring ( Jao et al., 2018 ); fifth, a highly resilient 3D-braided TENG as e-textiles for motion monitoring ( Dong et al., 2020b ).…”

“…Because the separate surface area is linearly correlated to the bending angles, the amplitude of output voltage can directly reflect the bending state. This quantification based on amplitude has been adopted in many researches ( Alam et al., 2020 ; Han et al., 2019 ; Liu et al., 2020 ; Yu et al., 2019 ). As a demonstration, five such kind of sensors are attached on to the fingers to monitor the motion of each finger and different gestures.…”

Flexible Textile‐Based Self‐Driven Sensor Used for Human Motion Monitoring

“…The principle of the self‐driven sensor is based on Maxwell's displacement current and the charges in surface polarization, which is the coupling of triboelectric effect and electrostatic induction [11a]. The self‐driven sensor is mainly composed of electrodes and positive and negative triboelectric materials, the positive and negative charge of the material depends on the strength of the ability of the two materials to avail and lose electrons when they are in contact . As long as two different materials come into contact, the material that attracts the electrons more strongly has a negative charge, and the other material has a positive charge .…”