Toward graphene textiles in wearable eye tracking systems for human–machine interaction

Abstract

The study of eye movements and the measurement of the resulting biopotential, referred to as electrooculography (EOG), may find increasing use in applications within the domain of activity recognition, context awareness, mobile human–computer and human–machine interaction (HCI/HMI), and personal medical devices; provided that, seamless sensing of eye activity and processing thereof is achieved by a truly wearable, low-cost, and accessible technology. The present study demonstrates an alternative to the bulky and expensive camera-based eye tracking systems and reports the development of a graphene textile-based personal assistive device for the first time. This self-contained wearable prototype comprises a headband with soft graphene textile electrodes that overcome the limitations of conventional “wet” electrodes, along with miniaturized, portable readout electronics with real-time signal processing capability that can stream data to a remote device over Bluetooth. The potential of graphene textiles in wearable eye tracking and eye-operated remote object interaction is demonstrated by controlling a mouse cursor on screen for typing with a virtual keyboard and enabling navigation of a four-wheeled robot in a maze, all utilizing five different eye motions initiated with a single channel EOG acquisition. Typing speeds of up to six characters per minute without prediction algorithms and guidance of the robot in a maze with four 180° turns were successfully achieved with perfect pattern detection accuracies of 100% and 98%, respectively.

Breathable Electronic Skins for Daily Physiological Signal Monitoring

“…It can be seen from the above sections that novel low-dimensional nanomaterials such as graphene, carbon nanotubes, and MXene play an important role in the study of breathable e-skin due to their excellent performances [ 5 , 13 , 31 , 36 , 37 , 49 , 55 , 67 , 68 , 74 , 75 , 78 , 89 ]. Apart from their advantages, the common advantages of the novel low-dimensional nanomaterials in the application of breathable e-skin include: (1) They have many physical and chemical advantages when used as electrode conductive materials, including the large specific surface area and flexibility suitable for the adhesion to a flexible interface like human skin, which helps reduce the electrode–skin contact impedance and ensuring high-quality signal acquisition; (2) easy to realize liquid phase processing, suitable for dip coating, spraying, and other simple processes to fabricate breathable e-skin; (3) good electrical properties, suitable for acting as conductive materials of e-skin electrodes, sensors, and systems; (4) due to the progress of preparation technology, their costs have been reduced compared with traditional precious metal materials, etc., both in terms of materials and fabricating methods; (5) their biocompatibility and stability are consistent with daily long-term skin wear requirements.…”

“…2 Categories Types Breathability Materials Fabrication Methods Refs. ECG electrodes Moisture-wicking and antibacterial e-skin Water vapor transmission rate (WVT) ~ 70% Dual-gradient poly (ionic liquid) nanofibers Electrospinning [ 29 ] 3D conductive textile e-skin 20 g m −2 h −1 Conductive elastomeric melt-spun filaments Industrial-scale knitting machine [ 30 ] Substrate-free e-skin hardly affects skin perspiration Laser-scribed graphene Sacrificial layer process [ 31 ] EOG electrodes Tattoo-like e-skin Breathable CVD graphene Sacrificial layer process [ 36 ] Textile-based e-skin Breathable Graphene-coated commercial fabrics Dip coating graphene oxide on fabrics and reducing [ 19 , 37 ] Soft-fabric-based e-skin Breathable 20% silver and 80% polyamide, sponge package Dip coated silver on the sponge [ 38 ] EMG electrodes All-nanofiber-based e-skin 1748.09 g m −2 d −1 HPAN, PU, and AgNWs Electrospinning and vacuum filtration [ 43 ] …”

Biosignal-Based Human–Machine Interfaces for Assistance and Rehabilitation: A Survey

“…Hence, they reflect the function of some organs (e.g., brain, muscles, eyes) in the form of electrical activity, providing relevant information about them [44,45]. For this reason, biopotentials are used as control signals in many biomedical HMI applications [25,42,[46][47][48][49][50][51][52][53][54][55][56][57][58][59]. These biosignals have their origin in electrophysiological phenomena associated with biochemical events occurring at a cellular level.…”

“…EOG-based assistive technologies can be used as nonverbal communication tools or for controlling a robot, a prosthesis, a wheelchair, a device in a smart environment, the cursor on a computer screen, and so on. Golparvar and Yapici designed a graphene textile-based wearable assistive device that allows eye tracking from EOG for remote control objects [56]. Zhang et al developed an EOG-based HMI for smart home environment control (e.g., TV control, air conditioner control, wheelchair control) in the case of SCI patients.…”

Wearable Triboelectric Sensors Enabled Gait Analysis and Waist Motion Capture for IoT‐Based Smart Healthcare Applications

“…Wearable or flexible electronics emerges as a rapidly developing research field in recent decades because of its intrinsical flexibility and lightness. [1,2] It offers a wide range of applications including motion monitoring, [3][4][5] rehabilitation, [6][7][8] human-machine interface (HMI), [9][10][11][12][13] disease diagnosis, [14][15][16] etc., to further improve the human's life quality. Among them, various wearable sensors are attached to the skin or worn on the body directly for sensory information collection with promising results distinguishing distinct body behaviors.…”