This paper presents a power-generating sensor array in a flexible and stretchable form. The proposed device is composed of resistive strain sensors, capacitive tactile sensors, and a triboelectric energy harvester in a single platform. The device is implemented in a woven textile structure by using proposed functional threads. A single functional thread is composed of a flexible hollow tube coated with silver nanowires on the outer surface and a conductive silver thread inside the tube. The total size of the device is 60 × 60 mm² having a 5 × 5 array of sensor cell. The touch force in the vertical direction can be sensed by measuring the capacitance between the warp and weft functional threads. In addition, because silver nanowire layers provide piezoresistivity, the strain applied in the lateral direction can be detected by measuring the resistance of each thread. Last, with regard to the energy harvester, the maximum power and power density were measured as 201 μW and 0.48 W/m², respectively, when the device was pushed in the vertical direction.

In this research, we propose a sensor system consisting of a power-generating sensor with a textile structure comprising piezoresistive, piezoelectric, and supercapacitor threads, and a circuit for efficient energy delivery. A multifunctional piezoelectric energy harvester for energy generation, piezoresistive strain, and capacitive tactile sensors to detect motion, and supercapacitor for energy storage were implemented through the proposed sensor platform. An energy management circuit was also added to the platform to store the generated energy and supply it for sensor operation. The devices were fabricated into a textile structure using functional threads in a total area of 130 mm × 130 mm with a 7 × 7 thread array. The piezoresistive strain sensor exhibited a resistance change of approximately 24% at a maximum strain of 24%, and the capacitive tactile sensor exhibited a change rate of 12.5% at a maximum vertical force of 5 N. In addition, the energy source, a piezoelectric energy harvester, obtained a power of 440 μ W at a 6 Hz motion and a 3 MΩ load resistor. In the energy management circuits, using a parallel synchronized switch harvesting on inductor (P-SSHI) circuit and a voltage doubler, increased the voltage stored in the supercapacitor by 119%.