SenseWear: Knitted Smart Textile Sensors

Keeping an eye on body performance and personal health, also called E-health, is becoming more and more popular. Smart wearables like fitness bands and smartwatches make this type of monitoring possible. As technology changes and improves constantly, clothing would be a perfect new medium to integrate technology in, as we are in contact with textiles daily.

In this project we developed a wearable garment with integrated knitted breathing and arm movement sensor. The arm sensor can detect small and large movements and has been tested from 10 - 40% strain. The breathing sensor is able to detect the small increase in the chest when the wearer is breathing.

Sensor Testing

Using the Stoll knitting machine sensor patches consisting of several knitted rows and colomns of conductive yarn were produced (Figure 1).

Figure 1: Overview of knitted test samples

Figure 2: Experimental test setup

Figure 3: Example of course sensor test

Figure 4: Example of wale sensor test

In a custom build tensile tester with 4 point resistance measuring unit (Figure 2) all knitted sensors were tested. Some examples are shown in Figures 3,4. The 1-line silver samples turned out to give incoherent signals, but 6-line samples (in course direction) and 2 line samples (in wale direction) were quite successful. Based on this a final sensing garment was designed and prototyped.

Final design

Kaspar Jansen

Project team

Graduate student

Daan van der Valk

Supervision

Kaspar Jansen (chair)
Tomasz Jaskiewicz (mentor)

Figure 5: color study

Figure 6: final design

Prototyping

Prototype details showing sensors and interconnections integrated into the shirt together with the processing unit. The sensor areas have similar stretchability compared to the rest of the shirt ensuring a maximum comfort level.