Paper‐Based Resistive Networks for Scalable Skin‐Like Sensing

Abstract This work presents a unique approach to the design, fabrication, and characterization of paper‐based, skin‐like sensors that use patterned resistive networks for passive, scalable sensing with a reduced number of interconnects. When touched or wetted with water, the sensors in the resistive networks detect significant changes in electrical impedance. Fabricating these resistive networks and sensors in a single sheet of metallized paper reduces the number of distinct inputs/outputs to the arrayed sensors. For human–electrode interactions, circuit‐based models guide the design/material processing of the resistive networks and selection of operating frequencies—typically ranging between 80 kHz and 1 MHz. As an example, a paper‐based touchpad with only two connecting wires (i.e., excitation and ground) functions as a 31‐button keypad. These resistive networks are also capable of spatially mapping contact with dispensed droplets of water in a dry environment and operating when bent. The reported results mark a technological advance in capacitive sensing with resistive networks to reduce the number of required interconnects while providing scientific understanding and modeling of human–electrode interactions for flexible electronic devices. Future skin‐like sensors with patterned resistive networks have the potential to contribute to scalable forms of human–machine interfaces, wearable devices, and liquid‐leak detectors.