A Simple Fabrication, Low Noise, Capacitive Tactile Sensor for Use in Inexpensive and Smart Healthcare Systems

Tactile sensors are among the most important devices used in industrial and biomedical fields. Sensors’ profiles are significantly affected by their structures and material used. This article presents a robust, low-cost, low noise, accurate and simple fabrication capacitive tactile sensor as a single taxel fabricated on foam. This highly scalable design provides excellent noise immunity, accuracy, and due to a unique printable elastic conductor, it is flexible and stretchable with more than 200% strain. Furthermore, the taxel is based on the capacitive Wheatstone bridge. As a result, noise immunity and stability in case of temperature fluctuation is accomplished. Additionally, the sensor’s innovative, simple fabrication, made of Polyurethane foam and printable elastic conductor, allows the system to adapt and achieve relevant results necessary for the purpose of the sensor’s application. Therefore, the proposed sensor has potential applications in industrial and biomedical contexts, such as sleep monitoring, etc.

I. Introduction

Pressure sensors are among the earlier devices achieved through silicon micromachining technologies that have become successful commercial products. These devices have been widely used for various industrial and biomedical applications [1]. A high number of different pressure sensors based on multiple measurement principles are already available on the market [2]. There are many pressure sensors that are able to measure pressure, but only some of them can measure tactile pressure conveniently with stable results. Also, due to the materials they use and the way they are designed, sensors are fragile, and only a few types of tactile sensors made with flexible materials have been reported [3]. These sensors can be based on piezoelectric, piezoresistive, capacitive, and resonant sensing mechanisms; and the pressure sensors currently on the market, capacitive and piezoresistive products are the most common [4]–[6].