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E-Textile ECG Contract Design

AUT IBTECH

Project Overview

In this project I worked as part of a larger research group, IBTech, at Auckland University of Technology. I was contracted to complete research and research through design to produce a variety of designs and fabrication techniques to help realize a functional ECG wearable using conductive textiles.  

This covered working with numerous stake holders, engineering speciaislists and technical experts. Design out puts frequently used conductive knit and conductive textiles in conjunction with additive manufacturing, CNC, 3D printing, silicone injection moulds and over moulding to solve challenges identified during research and design.

    • Reviewed literature on potentiality sensing and textile electrode technologies.

    • Reviewed deployment of textile based sensing in both ECG and EEG contexts.

    • Extensive literature review of wearable technology in medicine and industry.

    • Bench marked existing electrode types (Ag/AgCl, dry metal, conductive polymers, carbon-based).

    • Investigated challenges of skin–electrode interface: motion artifacts, impedance, user comfort.

    • Mapped the technology landscape for textile integration and potential industry partners.

    • Defined performance requirements for a wearable ECG device (signal quality, wash durability, skin comfort).

    • Identified constraints: low-noise acquisition, textile compatibility, scalability of fabrication.

    • Established testing metrics: signal-to-noise ratio, impedance stability, and user comfort.

    • Interviewed clinical staff and potential users for insights into deployment.

    • Developed multiple textile electrode prototypes using pre-tarnished conductive silver cloth and closed cell foam.

    • Designed layouts for chest placement within garments based on Lines of Non-Extension.

    • Balanced mechanical flexibility with electrical conductivity in material selection.

    • Designed around using machine knitting and whole knit/ 3D knit to create interfaces for hardware in the heart belt using heat mouldable yarns.

    • Designed embedded soft circuits to interface between hardware and electrode elements.

    • Fabricated prototype garments and electrode samples.

    • Used closed cell foam and conductive textiles in a vacuum forming process to create embossed textile electrodes.

    • Integrated electrodes with custom electrode housings and custom ECG circuitry.

    • Explored different attachment strategies (snap connectors, conductive threads).

    • Developed hardware housing interfaces used heat mouldable yarns (Permatex) to create variable density fabrics for semi hard attachment.

    • Used CNC to create steam moulds and vacuum forming moulds.

    • Created designs for using Permatex with machine knitting in conjunction with machined mould blocks for steaming fabric into three dimensional structures/latices within the belt.

    • Developed over moulding techniques for building gasket directly onto 3D formed knit structures.

    • 3D printed a variety of housings for ECG Hardware

    • Conducted bench testing for impedance and durability.

    • Performed human subject trials (ECG acquisition during rest and movement).

    • Compared signals against commercial Ag/AgCl electrodes as baseline controls.

    • Refined electrode structures to reduce impedance drift.

    • Adjusted textile layering and stitching to improve skin conformity.

    • Further developed silicone over moulding to pre-stretch skin and reduce motion artifact.

    • Incorporated wash-testing feedback into improved material choices.

    • Refined areas of Permatex on the ECG heart belt to provide better backing for electrodes and hardware.

Key Findings and Outcomes

  • Textile electrodes can provide clinically relevant ECG signals, though performance varies with fabrication method. Key challengers remain in impedance change over time due to sweat accumulation.

  • Motion artifact introduced by skin stretch and wash durability remain key challenges.

  • Machine knitting is a viable method of creating integrated garments and offers a base to use numerous technical yarns to achieve results

  • Using CNC to create steam moulds affords novel opportunities in creating hard set or variable stiffness structures within a single piece of fabric.

  • These variable structures further afford over moulding opportunities to create composite materials to great effect e.g. creating a draft silicone gasket around the textile electrode pre-stretched the skin around the electrode and reduced motion artefact signal processing

  • Heat mouldable yarns and CNC or 3D printing was a viable method of creating housings for hardware on soft structures or garments.

  • Outcomes informed future development of wearable health monitoring systems, demonstrating both technical feasibility and industry relevance.

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