5.4: A Textile Based Capacitive Pressure Sensor (original) (raw)

A textile based capacitive pressure sensor

2002

This paper introduces an approach for decoding the pressure information exerted over a broad piece of fabric by means of capacitive sensing. The proposed sensor includes a distributed passive array of capacitors (i.e. an array where no active elements are involved), whose capacitance depends on the pressure exerted on the textile surface, and an electronic system that acquire and process the subsequent capacitance variations. Capacitors can be made in different ways, though, in our demonstrator they have been implemented between rows and columns of conductive fibers patterned on the two opposite sides of an elastic synthetic foam. Measures performed over a prototype has been demonstrated the reliability of the approach by detecting pressure images at 3 F/s and by measuring capacitances as low as hundreds of fF spaced apart at meters of distance.

Design and Fabrication of a Capacitance Based Wearable Pressure Sensor Using E-textiles

This paper addresses the methods used for the design and fabrication of a capacitance based wearable pressure sensor fabricated using neoprene and (SAC) plated Nylon Fabric. The experimental set up for the pressure sensor is comprised of a shielded grid of sensing modules, a 555 timer based transduction circuitry, and an Arduino board measuring the frequency of signal to a corresponding pressure. The fundamental design parameters addressed during the development of the pressure sensor presented in this paper are based on size, simplicity, cost, adaptability, and scalability. The design approach adopted in this paper results in a sensor module that is less obtrusive, has a thinner and flexible profile, and its sensitivity is easily scalable for 'smart' product applications across industries associated to sports performance, ergonomics, rehabilitation, etc.

Textile capacitors as pressure sensors

The capacitance of a parallel-plate capacitor is proportional to its area and inversely proportional to the distance between the conductive plates. A variation of this distance can thus be measured by capacitance measurements. This principle can be used to detect a pressure on a certain area. While such capacitive pressure sensors are most often built from hard materials, the same principle can also be used to create a textile pressure sensor. In a current project, several materials have been examined for the possible use in textile capacitors. Opposite to recent attempts to create textile supercapacitors by coating or spinning (e.g. [1-3]), our project aims at a high pressure sensitivity which is not given by coated or spun capacitors in which the plate distance remains nearly constant for different pressures. Instead, several possible textile dielectrics with thicknesses in the mm range have been examined for varied plate distances. The poster gives an overview of the plate-distan...

Easy-to-Build Textile Pressure Sensor

Sensors (Basel, Switzerland), 2018

This article presents the design, construction, and evaluation of an easy-to-build textile pressure resistive sensor created from low-cost conventional anti-static sheets and conductive woven fabrics. The sensor can be built quickly using standard household tools, and its thinness makes it especially suitable for wearable applications. Five sensors constructed under such conditions were evaluated, presenting a stable and linear characteristic in the range 1 to 70 kPa. The linear response was modeled and fitted for each sensor individually for comparison purposes, confirming a low variability due to the simple manufacturing process. Besides, the recovery times of the sensors were measured for pressures in the linear range, observing, for example, an average time of 1 s between the moment in which a pressure of 8 kPa was no longer applied, and the resistance variation at the 90% of its nominal value. Finally, we evaluated the proposed sensor design on a classroom application consistin...

Impact of Fabric Properties on Textile Pressure Sensors Performance

Sensors

In recent years, wearable technologies have attracted great attention in physical and chemical sensing applications. Wearable pressure sensors with high sensitivity in low pressure range (<10 kPa) allow touch detection for human-computer interaction and the development of artificial hands for handling objects. Conversely, pressure sensors that perform in a high pressure range (up to 100 kPa), can be used to monitor the foot pressure distribution, the hand stress during movements of heavy weights or to evaluate the cyclist’s pressure pattern on a bicycle saddle. Recently, we developed a fully textile pressure sensor based on a conductive polymer, with simple fabrication and scalable features. In this paper, we intend to provide an extensive description on how the mechanical properties of several fabrics and different piezoresistive ink formulation may have an impact in the sensor’s response during a dynamic operation mode. These results highlight the complexity of the system due t...

A Comparative Characterization of Smart Textile Pressure Sensors

2019 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2019

This research study investigates the impact of various insulating textile materials on the performance of smart textile pressure sensors made of conductive threads and piezo resistive material. We designed four sets of identical textile-based pressure sensors – each of them integrating a different insulating textile substrate material. Each of these sensors underwent a series of tests that linearly increased and decreased a uniform pressure perpendicular to the surface of the sensors. The controlled change of the integration layer altered the characteristics of the pressure sensors including both the sensitivity and pressure ranges. Our experiments highlighted that the manufacturing design technique of textile material has a significant impact on the sensor; with evidence of reproducibility values directly relating to fabric dimensional stability and elasticity.

Development of pressure sensors for smart textiles

IOP Conference Series: Materials Science and Engineering, 2018

The investigation of textile sensors has increased and has gained an important role in the creation of new solutions for the most varied products, from monitorization sensors, actuators and controllers, implemented in garments, house textile items, or textiles structures used for a specific purpose e.g. bridge structural monitoring, soil proprieties, among others. This paper presents the development of pressure sensors base in a conductive silicone with piezoresistive conductive properties. The objective is to explore the combination of different types of conductive material (conductive silicon, nonconductive silicon, conductive ink and conductive fabric) and test the interactions between them. In the production methods the conductive ink, and conductive fabric were fixed to the silicone in the curing phase. Conductive and nonconductive silicon were mixed to obtain better control of sample conductivity. Samples with different thicknesses were developed, it was study the influence on the voltage variation and conductivity for each sample.

Wearable pressure sensor based on solution-coated fabric for pulse detection

2022 IEEE International Conference on Flexible and Printable Sensors and Systems (FLEPS)

Wearable devices have developed significantly due to the use and development of various materials such as organic materials and carbon nanotubes, and the demand for wearables is also growing. The piezoresistive pressure sensor has been developed using conductive fabric coated with a simple solution coating process. The fabric has an open structure with the interconnected top and lower layers that can be utilized as pressure sensors and can detect physical movements. The piezoresistive pressure sensor has excellent resistance linearity in the low pressure to 10kPa range, as well as consistent resistance to strain up to 20% when stretched. The pressure sensor array can detect pressure-induced local deformation and will be expected to contribute considerably to the development of wearable devices with a simplified process.

Conductive Fiber-Based Ultrasensitive Textile Pressure Sensor for Wearable Electronics

Advanced materials (Deerfield Beach, Fla.), 2015

A flexible and sensitive textile-based pressure sensor is developed using highly conductive fibers coated with dielectric rubber materials. The pressure sensor exhibits superior sensitivity, very fast response time, and high stability compared with previous textile-based pressure sensors. By using a weaving method, the pressure sensor can be applied to make smart gloves and clothes which can control machines wirelessly as human-machine interfaces.