A Study of Thermistor Performance within a Textile Structure

Abstract

Textiles provide an ideal structure for embedding sensors for medical devices. Skin temperature measurement is one area in which a sensor textile could be particularly beneficial; pathological skin is normally very sensitive, making the comfort of anything placed on that skin paramount. Skin temperature is an important parameter to measure for a number of medical applications, including for the early detection of diabetic foot ulcer formation. To this end an electronic temperature-sensor yarn was developed by embedding a commercially available thermistor chip into the fibres of a yarn, which can be used to produce a textile or a garment. As part of this process a resin was used to encapsulate the thermistor. This protects the thermistor from mechanical and chemical stresses, and also allows the sensing yarn to be washed. Building off preliminary work, the behaviour and performance of an encapsulated thermistor has been characterised to determine the effect of encapsulation on the step response time and absolute temperature measurements. Over the temperature range of interest only a minimal effect was observed, with step response times varying between 0.01–0.35 s. A general solution is presented for the heat transfer coefficient compared to size of the micro-pod formed by the encapsulation of the thermistor. Finally, a prototype temperature-sensing sock was produced using a network of sensing yarns as a demonstrator of a system that could warn of impending ulcer formation in diabetic patients.

Developing Novel Temperature Sensing Garments for Health Monitoring Applications

“…The use of textile temperature sensors allows for comfortable on-body temperature measurement, which is desirable for certain telemedicine and health monitoring applications. This work also presents a preliminary trial demonstrating a temperature sensing sock that was previously presented [1]. This trial creates new knowledge regarding skin temperature measurement of the foot using a textile-based temperature sensing garment.…”

“…This work focuses on using temperature sensing yarns, designed and characterized in earlier work [1,[23][24][25], to create a series of innovative textile sensing garments. A key component of this work was to conceptualize and identify the feasibility of developing temperature sensing textiles using temperature sensing yarns.…”

“…In order to integrate these temperature sensing yarns into garments, new knitting techniques had to be developed, creating important new knowledge. In addition to providing further details on the production of the temperature sensing sock [1], this work introduces a temperature sensing glove that could be used to create a temperature regulated glove for people with Raynaud's disease or those working in cold environments, and a temperature sensing armband for fever detection. The prototypes provide a fully textile-based solution to provide remote and continuous temperature measurements.…”

A Historical Review of the Development of Electronic Textiles

“…Such systems could have had applications in stroke rehabilitation [71]. There have also been other example of incorporating temperature-sensing elements into textiles [72][73][74][75].…”

Refinement of Temperature Sensing Yarns

“…This work builds on previous studies that have created a wearable temperature sensing yarns [5,6]. Further to earlier work, this study focuses on absolute temperature measurements as well as temperatures outside of those that would normally be physiologically relevant.…”