2023 AIChE Annual Meeting
Fabricating Cost-Effective, Wireless Pressure Sensors Using Piezoresistive Electronic Textiles.
Electronic textiles, also known as eTextiles, are fabrics that contain electronic capabilities. With their ability to conduct electricity, eTextiles have become widespread in the field of soft robotics over the past few years. ETextiles allow people to embed various electronic components in fabrics to transform them into flexible and wearable electronics. For this study, Velostat® is used to create a wearable pressure sensor matrix. The 6âx6â matrix consists of 64 sensor points created by intersecting 8 rows and 8 columns of copper tape. The copper tape is compatible with the pressure sensor matrix due to its flexibility and good conductivity. When pressure is applied on any sensor point, it will relay a value to an ATmega328 microcontroller that corresponds to the amount of pressure placed. As more pressure is placed, resistivity of the fabric decreases, allowing more voltage to flow through that point and the microcontroller relays a higher analog value. The analog values range from 0 to 1023 corresponding to approximately 0N to 3N of force. 2 HC-05 Bluetooth® modules (one connected to the matrix circuit, one connected to a computer) are used to transfer the values from the microcontroller to a computer. The processing code on the computer creates an image of 64 squares that change color based on a gradient that corresponds with the analog values. The circuitry, consisting of the Bluetooth® module, a solderable protoboard, and a 4.5V battery pack, is placed inside a small acrylic box. 16 ribbon cables, attached to the 8 rows and 8 columns, are connected to 2 multiplexers on the board, which relay voltage to and from the matrix. Faux leather is used to encase the Velostat® and copper tape to provide flexibility and comfort to the wearer.
The purpose of this study is to provide an affordable and simple method of using eTextiles, like Velostat®, to create flexible, wearable sensors. The application of these flexible sensors shows promise in the field of exoskeleton research, where external pressures placed on the body by exoskeletons can be evaluated for fit and comfort. Other fields of application include human-computer interaction, prosthetics, and motion capture.