Sports acTivitiEs With weARable Technology (STEWART)
Grant agreement ID: 221N310
Funded by TUBITAK-IraSME (International research activities by Small and Medium-sized Enterprises)
Start Data: 01.09.2022 - End Date: 01.09.2024

The measurement of human body movements and physiological signals is used in areas such as physiotherapy, performance monitoring and virtual reality (VR). Today, there are many different motion capture and solid physiological signal measurement systems. However, these systems have disadvantages such as low comfort, high stiffness, sensitivity to various factors, and high cost. The aim of the research is to develop a textile-based wearable sensor system integrated into a t-shirt to improve the effectiveness of performance monitoring and tracking applications. The T-shirt is designed to protect individuals through early or real-time detection of risks that may arise during daily and sports activities. Research and development activities are planned in computer, textile, electronics, and biomedical engineering. For this purpose, the following objectives have been addressed:

Design and Production of Capacitive Based Strain Sensors: The sensors are produced in the form of flexible interfaces. These interface fabrics were manufactured using conductive yarns for the electrode layer and non-conductive yarns for the dielectric layer.

Use of Capacitive Strain Sensors in the Detection of Round Shoulder Posture: The sensors integrated in the t-shirt react to shoulder and trunk movements and increase the capacitance in flexion and return to the initial level in extension. The sensors were positioned with the help of a literature review and input from expert physiotherapists to accurately capture upper body kinematics. The design optimizes sensor size and position to maximize measurement accuracy and maintains constant contact with the body, which ensures accurate detection of the specified posture.

Development of Textile Based Electrodes for ECG and Respiratory Monitoring: Interface fabric electrodes were produced using conductive and non-conductive yarns as filling material. Considering the effect of the contact force with the human body on ECG measurement quality, design improvements have been made for optimum electrode area and improved contact.

Development of Textile Based Electrodes for ECG and Respiratory Monitoring: Interface fabric electrodes were fabricated using conductive and non-conductive yarns as filling material. Considering the effect of the contact force with the human body on ECG measurement quality, design improvements have been made for optimum electrode area and improved contact.

Characterization of Textile Based Strain Sensors and Electrodes: Individual sensors and electrodes were used in testing to determine the appropriate design in terms of functionality and comfort characteristics. Based on the characterization results, suitable designs were selected for smart t-shirt production.

Smart T-shirt Development with Integrated Sensors and Textile Based Transmission Lines: The development of a fully integrated T-shirt including embedded sensors, textile-based transmission lines and laboratory tests was carried out at this stage. Components such as electrical circuits, battery, microcontrollers and Bluetooth transmitters that cannot be integrated into the textile are integrated into the t-shirt through a 3D printed cover.

Data Collection Software and Mobile Application Development: Kinematic data and physiological signals (heart rate, ECG, respiration) of upper body movements are collected in real time, converted to numerical data in the app, and used to model posture on a virtual avatar. Heart rate and respiration are displayed on the dashboard with historical data.
As a result, within the scope of STEWART, a smart t-shirt with integrated textile-based sensors and electrodes has been developed. Extensive characterization and performance evaluations were carried out to assess the effectiveness of the smart t-shirt in different applications. These evaluations were supported by machine learning based analyses and the potential of textile integrated sensor technology was highlighted.