Arrayed Force Sensors Made of Paper, Elastomer, and Hydrogel Particles

Abstract

This article presents a sensor for detecting the distribution of forces on a surface. The device with nine buttons consisted of an elastomer-based layer as a touch interface resting on a substrate of patterned metallized paper. The elastomer-based layer included a three-by-three array of deformable, hemispherical elements/reliefs, facing down toward an array of interdigitated capacitive sensing units on patterned metallized paper. Each hemispherical element is 20 mm in diameter and 8 mm in height. When a user applied pressure to the elastomer-based layer, the contact area between the hemispherical elements and the interdigitated capacitive sensing units increased with the deformation of the hemispherical elements. To enhance the sensitivity of the sensors, embedded particles of hydrogel in the elastomer-based layer increased the measured electrical responses. The measured capacitance increased because the effective dielectric permittivity of the hydrogel was greater than that of air. Electromechanical characterization verified that the hydrogel-filled elastomer was more sensitive to force at a low range of loads (23.4 pF/N) than elastomer alone without embedded hydrogel (3.4 pF/N), as the hydrogel reduced the effective elastic modulus of the composite material by a factor of seven. A simple demonstration suggests that the force-sensing array has the potential to contribute to wearable and soft robotic devices.

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.…”

Hydrogel Pressure Distribution Sensors Based on an Imaging Strategy and Machine Learning

“…It should be noted that researchers have produced a plethora of hydrogel pressure sensor devices. ,,− However, these pressure sensors are only able to sense the pressure at one point. To measure pressure distribution, multiple hydrogel pressure sensors are arranged so as to prepare an array-type pressure distribution sensor device. − However, the sensing area of such devices is not continuous, and they are only able to respond to the pressure applied to hydrogel pressure sensing units with extremely low resolution. More importantly, higher resolution means more sensing units and more complicated wires arranged in the sensing region.…”

High-Performance Resistive Pressure Sensor Based on Elastic Composite Hydrogel of Silver Nanowires and Poly(ethylene glycol)

“…Recently, flexible electronic devices capable of transducing physical phenomena, such as pressure, strain, and temperature, into electrical signals have received considerable attention for use in next-generation wearable electronics for health monitoring [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. Particularly, a number of research groups have been pursuing the development of high-performance pressure sensors with high flexibility, optical transparency, and ultrahigh sensitivity, because of their wide range of potential applications in robotics and medicine, and applications to specific devices including smart phones, touch screen devices, and electronic skin [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. Various types of pressure sensors exist, and are typically categorized by their transduction mechanisms.…”