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Guess et al. Soft Sci 2023;3:23 Soft Science
DOI: 10.20517/ss.2023.17

Research Article Open Access

Wireless batteryless soft sensors for ambulatory

cardiovascular health monitoring

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Matthew Guess , Ira Soltis , Bruno Rigo , Nathan Zavanelli , Sara Kapasi , Hyeonseok Kim , Woon-
Hong Yeo 1,2,4,5,*
1
George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
2
IEN Center for Human-Centric Interfaces and Engineering, Institute for Electronics and Nanotechnology, Georgia Institute of
Technology, Atlanta, GA 30332, USA.
3
School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
4
Wallace H. Coulter Department of Biomedical Engineering, Georgia Tech and Emory University School of Medicine, Atlanta, GA
30332, USA.
5
Parker H. Petit Institute for Bioengineering and Biosciences, Neural Engineering Center, Institute for Materials, Institute for
Robotics and Intelligent Machines, Georgia Institute of Technology, Atlanta, GA 30332, USA.
* Correspondence to: Dr. Woon-Hong Yeo, George W. Woodruff School of Mechannical Engineering and IEN Center for Human-
Centric Interfaces and Engineering, Institute for Electronics and Nanotechnology, Georgia Institute of Technology, 791 Atlantic
Drive NW #204, Atlanta, GA 30332, USA. E-mail: whyeo@gatech.edu
How to cite this article: Guess M, Soltis I, Rigo B, Zavanelli N, Kapasi S, Kim H, Yeo WH. Wireless batteryless soft sensors for
ambulatory cardiovascular health monitoring. Soft Sci 2023;3:23. https://dx.doi.org/10.20517/ss.2023.17
Received: 17 Apr 2023 First Decision: 11 May 2023 Revised: 23 May 2023 Accepted: 1 Jun 2023 Published: 10 Jul 2023
Academic Editors: Dae-Hyeong Kim, Zhifeng Ren Copy Editor: Dong-Li Li Production Editor: Dong-Li Li

Abstract
Seismocardiography (SCG) is the measure of local vibrations in the chest due to heartbeats. Typically, SCG signals
are measured using rigid integrated circuit (IC) accelerometers and bulky electronics. However, as alternatives,
recent studies of emerging flexible sensors show promise. Here, we introduce the development of wireless soft
capacitive sensors that require no battery or rigid IC components for measuring SCG signals for cardiovascular
health monitoring. Both the capacitive and inductive components of the circuit are patterned with laser
micromachining of a polyimide-coated copper and are encapsulated with an elastomer. The wearable soft sensor
can detect small strain changes on the skin, which is wirelessly measured by examining the power reflected from
the antenna at a stimulating frequency. The performance of the device is verified by comparing the fiducial points
to SCG measured by a commercial accelerometer and electromyograms from a commercial electrode. Overall, the
human subject study demonstrates that the fiducial points are consistent with data from commercial devices,
showing the potential of the ultrathin soft sensors for ambulatory cardiovascular monitoring without bulky
electronics and rigid components.

Keywords: Soft sensor, capacitive strain sensor, passive wireless, laser micromachining, LC resonance sensor,
ambulatory monitoring, cardiovascular health

© The Author(s) 2023. Open Access This article is licensed under a Creative Commons Attribution 4.0
International License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, sharing,
adaptation, distribution and reproduction in any medium or format, for any purpose, even commercially, as
long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and
indicate if changes were made.

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