Stretchable Strain Sensor: Characterization And Applications

Since their development, stretchable sensors have attracted significant interest owing to their distinctive attributes of being highly flexible and stretchable without compromising performance, as well as being lightweight and adaptable to various surfaces and wearable technologies. These sensors have found widespread application in fields such as healthcare and sports, ensuring comfort for users. However, for optimal performance in these applications, a thorough characterization is crucial. In this study, a capacitive-type stretchable strain sensor based on an elastomer was characterized with the particular aim of integrating it into wearable health systems and sports clothing for human activity recognition. Thanks to a stepper motor, static and dynamic tests were conducted applying controlled stretches to the sensor, while video recording allowed the accurate extraction of the strain. A linear relationship between sensor output and stretch was observed in both conditions, while hysteresis behavior was revealed in continuous stretch analysis. Results show good performances with a stretch error introduced by the conditioning system and by the output drift in the range of 1.4%. In the end, the sensor was employed to distinguish signals between walking and different types of kicks, applying it to the knee. Motion study showed the possibility to use this sensor in human activity recognition field.