Paper‐Based Resistive Networks for Scalable Skin‐Like Sensing

Abstract

user interface. In other words, increasing resolution or adding sites for the detection of touch, generally requires augmenting the number of interconnects. With the exception of using a single electrode-based sensing technique to make natural and inanimate objects become user interfaces, there has been a lack of effort in the reduction of the number of wired leads required for scalable sensing of touch. [9] In contrast to electronic touch sensors, skin on humans/vertebrates uses hierarchical neural networks to transmit the relative spatial detection and intensity of force on fleshy surfaces to the brain. [10] These neural networks do not depend on having a pair of running wires for each location. Instead, they have developed mechanisms for sending spatial information about touch along the spinal cord. Inspired by this concept, Tee et al. presented a skininspired organic digital mechanoreceptor, which converted force-based stimuli into digital signals with varied frequencies to mimic the communication between biological mechanoreceptors and the brain. [11] Similarly, there are opportunities to build electrical networks to reduce the number of wired leads required for spatial detection of touch on synthetic electronic skins.The advancements in skin-like sensing with flexible electronics have moved toward the design and fabrication of active electronic components arrayed on flexible sheets with surface areas less than 10 cm in diameter. [12][13][14][15][16] For example, Someya and co-workers demonstrated an application of thin-film transistors in skin-like sensors capable of measuring distributed pressures over a 9 cm × 9 cm footprint. [12] The size of the sensors is typically dependent on the method of fabrication, and current skin-like sensors often cover small areas (i.e., much less area than that of human skin) because of the limited size of semiconductor-based wafers. As mentioned previously, the number of wired leads in conventional arrays of skin-like sensors increases with the square root of the number of buttons. While this scaling may appear favorable, there are still difficulties with making large sensing grids, as a larger quantity of traces requires more space for wired connections and multiplexed measurements.In this work, we present an approach to passive sensing for skin-like sensors consisting of tunable resistive networks and 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...

Printed Smart Devices on Cellulose-Based Materials by means of Aerosol-Jet Printing and Photonic Curing

“…The reason of the interest in paper materials is related to its unique combination of properties, like biodegradability, biocompatibility, and renewability, thus reducing waste production, important aspects in an environmental-friendly manufacturing context [1]. Paper-based substrates show an intrinsic versatility since different kind of paper can be used as suitable materials depending on the application, from printer paper [2,3], glossy brochure paper, newspaper, cardboard [4] to photopaper [5], and chromatographic paper [6]. Being a disposable material, paper-based sensors have proven their validity in studies of biological samples in laboratories, but they can show their usefulness in resource-limited situations owing to low-cost, robustness and ease-of-disposal, simply burning the device in presence of biological samples avoiding sterilization [7,8].…”

Experimental Estimation of Gap Thickness and Electrostatic Forces Between Contacting Surfaces Under Electroadhesion

“…It is important to emphasize here that the electrical impedance measurements of human skin may show variations from trial to trial within an individual participant and between different participants as reported for finger skin in earlier studies. [ 48 ] The impedance magnitude of skin, similar to its resistance, was found to be higher when measured with metal electrodes compared to hydrogel electrodes due to the effect of electrode polarization impedance. Moreover, the electrode polarization impedance caused phase lag in the impedance response.…”

Paper-Based Robotics with Stackable Pneumatic Actuators

“…P aper continues to receive attention as a material for electronics and robotics due to its low cost, recyclability, and foldability. For electronics, many state-of-the-art paperbased devices have included sensors, [1][2][3][4][5][6] methods of energy storage, [7][8][9] transistors, [10][11][12][13] and electrochemical detectors. [14][15][16] Paper-based robots benefit from the folding and cutting techniques of paper-origami/kirigami-to achieve large deformation.…”