We present a first-of-its-kind fabric hydrogel electrode that is reusable and washable, does not cause skin irritation, and can be continuously operated for upward of 8 h without losing signal integrity. Second, we report an ion-based fabric pressure sensor that measures pulse waveforms when placed on the face. We decorate a lightweight eye mask with these novel fabric electrodes to create a portable detection platform named ''Chesma,'' which can wirelessly track eye motion and pulse in natural environments over long periods of time.
Wearable sensors allow for portable, long-term health monitoring in natural environments. Recently, there has been an increase in demand for technology that can reliably monitor respiration, which can be indicative of cardiac diseases, asthma, and infection by respiratory viruses. However, to date, the most reliable respiration monitoring system involves a tightly worn chest belt that is not conducive to longitudinal monitoring. Herein, we report that accurate respiration monitoring can be effected using a fabric-based humidity sensor mounted within a face mask. Our humidity sensor is created using cotton fabrics coated with a persistently p-doped conjugated polymer, poly(3,4-ethylenedioxythiophene):chloride (PEDOT-Cl), using a previously reported chemical vapor deposition process. The vapor-deposited polymer coating displays a stable, rapid, and reversible change in conductivity with an increase in local humidity, such as the humidity changes experienced within a face mask as the wearer breathes. Thus, when integrated into a face mask, the PEDOT-Cl-coated cotton humidity sensor is able to transduce breaths into an electrical signal. The humidity sensor-incorporated face mask is able to differentiate between deep and shallow breathing, as well as breathing versus talking. The sensor-incorporated face mask platform also functions both while walking and sitting, providing equally high signal quality in both indoor and outdoor contexts. Additionally, we show that the face mask can be worn for long periods of time with a negligible decline in the signal quality.
The strategy of detecting physiological signals and body movements using fabric-based pressure sensors offers the opportunity to unobtrusively collect multimodal health metrics using loose-fitting, familiar garments in natural environments. (A. Kiaghadi, S. Z. Homayounfar, J. Gummeson, T. Andrew, and D. Ganesan, Proc. ACM Interact. Mob. Wearable Ubiquitous Technol., 3, 1–29 (2019)). However, many sensing scenarios, such as sleep and posture monitoring, involve an added static pressure from exerted body weight, which overpowers weaker pressure signals originating from heartbeats, respiration and pulse and phonation. Here, we introduce an all-fabric piezoionic pressure sensor (PressION) that, on account of its ionic conductivity, functions over a wide range of static and dynamic applied pressures (from subtle ballistic heartbeats and pulse waveforms, to larger-scale body movements). This piezoionic sensor also maintains its pressure responsivity in the presence of an added background pressure and upon integration into loose-fitting garments. The broad ability of PressION to record a wide variety of physiological signals in realistic environments was confirmed by acquiring heartbeat, pulse, joint motion, phonation and step data from different body locations. PressION’s sensitivity, along with its low-cost fabrication process, qualifies it as a uniquely useful sensing element in wearable health monitoring systems.
Unobtrusive and continuous monitoring of cardiac and respiratory rhythm, especially during sleeping, can have significant clinical utility. An exciting new possibility for such monitoring is the design of textiles that use all-textile sensors that can be woven or stitched directly into a textile or garment. Our work explores how we can make such monitoring possible by leveraging something that is already familiar, such as pyjama made of cotton/silk fabric, and imperceptibly adapt it to enable sensing of physiological signals to yield natural fitting, comfortable, and less obtrusive smart clothing. We face several challenges in enabling this vision including requiring new sensor design to measure physiological signals via everyday textiles and new methods to deal with the inherent looseness of normal garments, particularly sleepwear like pyjamas. We design two types of textile-based sensors that obtain a ballistic signal due to cardiac and respiratory rhythm ---the first a novel resistive sensor that leverages pressure between the body and various surfaces and the second is a triboelectric sensor that leverages changes in separation between layers to measure ballistics induced by the heart. We then integrate several instances of such sensors on a pyjama and design a signal processing pipeline that fuses information from the different sensors such that we can robustly measure physiological signals across a range of sleep and stationary postures. We show that the sensor and signal processing pipeline has high accuracy by benchmarking performance both under restricted settings with twenty one users as well as more naturalistic settings with seven users.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.