Development of Kirigami-Based Strain Sensors Printed on Medical Dressing for On-Skin Monitoring

Gesture recognition using wearable sensors is a useful method for humans to interact with intelligent machines such as robots and computers. These wearable devices can be coupled with exoskeletons to assist patient rehabilitation, especially for stroke patients. While electromyography can be used to measure electrical activity accurately from muscles, analysis of these signals often requires more complex hardware. Strain sensors on the other hand provide a simpler method of detecting different hand gestures by measuring change in resistance. In this work, we describe the design and usage of soft, comfortable strain sensors which are screen-printed on Tegaderm™, a self-adherent bandage. The sensors are in the form of serpentine, kirigami, carbon electrodes. Twenty-four different designs were fabricated and evaluated. The resistance versus strain measurements were performed and the results of the five most sensitive sensors were plotted. Tensile measurements to determine the Young’s Modulus of the Tegaderm™ sensors were also done. To illustrate the change in morphology that occurs on the strain sensors, the microscope images of before and after strain were also made.