Design and Implementation of a Textile-Based Sensor for Wearable Rehabilitation Technologies

Strain sensors based on textiles can provide body movement feedback with various advantages, such as comfort, ease of incorporation into conventional clothing, and washability. In this paper, a textile-based strain sensor is designed and fabricated with conductive threads to measure the bending angle of hand fingers. In this case, the resistance of this sensor changes with respect to the applied strain when the finger is bending. A commercially available yarn made of $100 \%$ stainless steel fibers, which could have a high level of durability against friction and erosion, was used. For the experimental results of this sensor, a novel setup was designed and implemented to take the desired tests in which the angle and the speed of rotation can be adjusted. This apparatus was created to simulate finger flexion. The results showed that the proposed sensor is capable of recognizing the angle of fingers through a low range of electrical resistance change but with low hysteresis (less than $15 \%$). Furthermore, the sensor indicated a gauge factor exceeding 0.6 at a low speed of 0.5 revolutions per minute, which has the potential to increase at higher speeds. It is envisioned that this sensor can be employed in the field of rehabilitation to provide feedback on the patient’s range of motion or even daily rehabilitation exercises that can be monitored and checked by therapists but with less precision.