Stretchable Multi-mode Sensor with Yarn Structure

Recently, there has been an emergence of advanced sensor technologies that append promising traits and compensate for problems in conventional sensors. The term “multi-functionality” is used to describe this trend of advancing conventional technologies in this field, such as endowing a sensor to be stretched or to sense multiple forces. Even with this trend, sensors exhibiting both stretchability and multi-modality have been barely explored. We introduce a multi-mode sensor with three modes to distinguish multiple motions: clockwise twisting, counterclockwise twisting, and stretching. It comprises of piezoelectric and piezoresistive sensors and is constructed in yarn structure with those two parts. With a stretchable substrate, this sensor exhibits stretchability. Moreover, by using the electrohydrodynamic spray method for depositing carbon nanotubes on the surface of substrates, a stretchable electrode layer for the piezoelectric sensor is developed. By responding differently with each external stimulus, the multi-mode sensor can determine forces applied on it. We also suggest a mathematical model to distinguish simultaneous stimuli.