Creating flexible electronic technology, however, presents some obstacles in simply having to work with textiles. These NC State researchers fabricated an embroidered-based touch sensor that could improve their scalability as that seems to be a market challenge.

How NC researchers created this smart textile

They created a yarn from two triboelectric materials, which refers to an electric charge produced by friction. An everyday example might be the electric shock one experiences from running a plastic comb through dry hair or by touching a piece of fabric on a dry day.

Using two triboelectric materials with a positive and negative charge, they weaved a sensor into a fabric with an embroidery machine. And these yarns together create the appropriate electric charge. An electric sensor sends signals to a microchip as this smart textile is controlled by touch. Thus the device has two parts.

Machine learning algorithms enable the device to understand commands such as “tap two times” or “swipe” to increase or decrease the volume. They demonstrated that they could control apps on one’s phone with it. These algorithms can even detect mistakes or glitches that weather might trigger.

This is the definition of a “smart textile.”

They explained that they integrated “multiple embroidery sensors onto a single piece of fabric in a grid formation for enabling more complicated sensing applications and control interfaces.”

If we take a moment to contemplate a weave, meaning how threads come together to create patterns, that’s the level of sophistication that these NC researchers have achieved.

In a video, NC State researchers played a video game on the fabric. They could control a character almost entirely with one finger. Walk forward, turn around, attack, go back. Just with a series of taps and swipes.

Though still evidently in its early stages as a piece of technology, they demonstrated that wearable textile technology works well.

A smart textile that capitalizes on old and new technologies

The researchers had to figure out the size of the gap between the two layers as triboelectric materials require a space between them. In a diagram, they showed that they experimented with three gap sizes as they weaved thread into a piece of fabric.

“To create extra space for separation and enhance triboelectric output, we placed spacers (a piece of cardboard) on straight embroidery with heights of 1 mm, 2 mm, and 3 mm during satin structure embroidery and removed it when embroidery was finished. The addition of spacers allows more yarn to occupy the same embroidery path, creating an overall arched shape.”

Ron Ying, a NC researcher, explained that “existing embroidery technology is not capable of easily handling the types of materials used in the creation of the sensor,” which means special embroidery machines would have to be built. (Call MIT.) They showed, however, that they could program this sensor to recognize a complex set of commands.

In the near future, we might be able to not necessarily replace the iPhone watch but achieve the same functionality and more with a fabric sensor that’s pretty much the size of a button.