Laser-Induced Graphene Strain Sensor for Conformable Lip-Reading Recognition and Human–Machine Interaction

Abstract

Lip-reading recognition (LRR) has gained significant attention due to its potential applications in various scenarios, such as communication for the speech-impaired, conversations in noisy or dark environments, and human–machine interactions. However, existing LRR technologies based on computer vision suffer from drawbacks such as the high cost of electronic camera equipment and the negative impact of ambient lighting on recognition accuracy. Herein, a graphene-based flexible strain sensor is developed through a facile, high-efficiency, and low-cost laser-induced carbonization technique, which involves the ablation of polyimide (PI) films using ultraviolet lasers. The sensor’s patterned stripes and porous structure endow it with sensitivity to deformations caused by bending and pressing. The well-designed flexible strain sensor can tightly attach on facial skin and record high-quality strain signals of various lip muscle movements. When compared to a preconstructed lip-reading database using a fixed algorithm, the collected lip-reading signals exhibit a recognition rate exceeding 90%, enabling seamless human–machine interaction and precise control over manipulators. Consequently, the LRR approach based on the flexible strain sensor demonstrates immense potential as a promising platform for speech-impaired communication and human–machine interactions in variable environments.

A Flexible Wearable Sensor Based on Laser-Induced Graphene for High-Precision Fine Motion Capture for Pilots

“…Different wavelength lasers, such as a 355 nm ultraviolet femtosecond laser [ 24 ], a 522 nm green femtosecond laser [ 25 ], and a 10.6 μm CO 2 infrared laser [ 16 ], can be used to irradiate the surface of various carbon precursor materials to produce LIG. However, different laser parameters, including the pulse duration, radiation energy, scanning speed, and laser power, significantly affect the morphology and performance of LIG [ 26 , 27 , 28 , 29 , 30 , 31 ]. The effects of these laser parameters on LIG characteristics can be studied by varying individual parameters [ 23 ].…”

A high-performance, sensitive, low-cost LIG/PDMS strain sensor for impact damage monitoring and localization in composite structures

“…However, the sensor has a nonlinear response with a narrow working range (up to 10%). In contrast to the co-mixing method, laser etching helps overcome issues such as agglomeration and uneven dispersion of graphene materials [28,29].…”

“…For instance, Cheng et al utilized infrared laser etching on PI film to fabricate strain sensors with a remarkable cycle number of 1400, demonstrating high detection accuracy even for small strain actions [29]. Chhetry et al obtained MoS 2 -decorated laser-induced graphene by carbonizing a MoS 2 -coated polyimide film.…”

Flexible Wearable Strain Sensors Based on Laser-Induced Graphene for Monitoring Human Physiological Signals

“…LIG can be synthesized using diverse carbon precursors, including renewable sources such as trees [14], paper [15], and cloth [16], as well as high-performance polymers such as polyetherimide (PEI) [17], phenolic resin (PR) [18], polydimethylsiloxane (PDMS) [19], poly-ether-ether-ketone (PEEK) [20] and polyimide (PI) [21]. Therefore, LIG is considered as one of the best methods to produce high-performance flexible wearable sensors [22], and LIG-based flexible wearable sensors offer promising market prospects in various fields, including smart wearable electronic devices, medical rehabilitation, and scientific exercises [23][24][25]. Chen et al [26] prepared LIG on the surface of PI with square, zigzag, and shutter patterns, where shutter-patterned E-skins were able to be used to detect various physiological signals and had an alarm function when an abnormal situation was detected.…”