E-textile is a booming market in the electronics sector—and in the textile sector. Being at the crossroads of two industries has problems of its own. Christian Dalsgaard, founder and former CTO of Ohmatex in Denmark, learned that the hard way while developing state-of-the-art wearables for the European Space Agency, among others. He argues for standards in e-textile. Senior Technology Editor of Electronic Design Bill Wong chats with Christian about this growing need.
Which problems are shaping e-textile nowadays?
There are two clusters of problems—the first cluster has to do with the central challenges of e-textile. The most important one is unifying something hard with something soft, something rigid with something flexible. Also, you need to make a device as small as possible, while maintaining its performance. And then there’s the challenge to make cabling, connectors and electronics sealing that will survive hostile environments—sweat, washing machines, tumble dryers, to name the most obvious.
The second cluster of problems is about the fact that two supply chains are involved in e-textile. One is concentrated around the traditional textile industry, where there’s a group of companies involved in the production of conductive yarn, sensing fabrics, and confectioning garments. The other is concentrated around the production of electronics and mechanical components, involving robotics and automated processes.
Textile and electronics are coming together in e-textile, but they come from very different backgrounds. Some of the elements include price points that are very different and the manufacturing process for cloth is still labor-intensive.
Moreover, the turnaround time in fashion is short. There needs to be a new collection every three months, whereas the turnaround time in electronics is on average two years. Of course, there are exceptions—certain headphones from 2007 are still hot and being sold.
People working in electronics are generally nerds rooted in STEM, while in textile they hate mathematics and science. There’s also a gender factor. In the textile industry, there’s a predominance of women, while in electronics you’ll find mostly men.
The gender aspect influences the industry on many levels, from the people working in it to the solutions consumers are interested in. Women choose clothes for being comfortable, or for expression, while expression is much less of an issue for men, who rather look for functionality in their clothes—to protect themselves from heat or cold. These factors play a minor role in electronics. In short, each industry has its own standards and accepted solutions, embedded in very diverse industrial history and cultures.
Which problems in e-textile are suffering most from the lack of standardization?
Imagine a world of mobile phones without USB or Bluetooth standards. A supplier would need to develop headsets, hands-free car kits, loudspeakers, and many other accessories—each device individually designed for a specific brand. This is the situation e-textile is in, which we need to get out of as fast as possible.
First, let’s discuss connectors. They need to be soft and easy to integrate, but most of them are clumsy, rigid, and hard, especially in the military. Connectors in the consumer market, such as USB and USB-C, are much more consumer-friendly because they’re small and widely used. However, they’re fragile when applied to cloth, and tend to gather dirt and washing powder when being washed.
We struggled with the connector in the PLACE-it project—a project Ohmatex was involved in with, among others, Philips. For this project, we developed a connector for light-emitting textiles used in phototherapy medical devices for treating babies with jaundice, or people with skin disease. To properly make the connector, we had to develop it from scratch. It was a beautifully thin and flexible interconnect that we unfortunately couldn’t afford to upscale because there was no standard we could apply to the thin design.
Another problem is wiring for both power and data transfer, which needs to be flexible and must be sewn or glued into seams. There are no bus standards, textile cables, or washable interconnects that can be used straight out of the box. You need to combine a mix of wires, textile yarns, and elastic weaving methods with custom, specific connectors. And you need to solve the strain relief to prevent the wires from breaking quickly. Finally, you need shielded cables to isolate radiation and radio interference.
Making wearable processing units are a nightmare, too. A skiing jacket with heating elements, for example, needs a controlling unit with an on/off switch, an LED panel, and controls for power level, temperature levels etc. The same goes for ECG shirts, where the interface controls are very similar. If you were building a computer, you would buy, for instance, a standard network board, a graphic card from Asus or G-force—components that are plug-and-play.
In e-textile, you sit together with an electronic engineer who has, by that time, already been working on it for months—ordering resistors, capacitors, ICs; working at a breadboard, etc. And then you’re only just getting started! Compared to making computers, making a garment in e-textile is like making the garment AND having to invent zippers, reflectors, yarn, a sewing machine and a washing machine—and don’t forget the washing powder, too!
Developers are struggling not only with the absence of standards, but also with the non-existence of industrially proven solutions. You can find breathable and stretchable conductive fabrics that are used for many bio-sensing applications, like ECG, skin temperature measurement, and motion capturing.
But such fabrics are hard to fixate to a foil-based electronics board, which is industry standard in electronics. There’s no glue specifically developed for this purpose, so as a developer you need to conduct a lot of experiments yourself with pressure, heat, etc., before you can find the right combination that works for the wear and tear endured by that e-textile.
Speaking of wear and tear, washing is a good example of where the two supply chains need to join forces and be willing to venture out in each other’s field of expertise. Take, for instance, soft displaying—they have to endure washing when built into a sleeve. Here responsibility lies with both parties, but some people in electronics have been known to elegantly drop the responsibility like a hot potato, saying “washing is not our task.”
Yet I have also witnessed the textile side saying the same thing: “Oh, that’s electronics, we know nothing about that.” Yes, but in the case of washing there is, for obvious reasons, far more expertise on the textile side than on the electronics side! You can see how this slows down the development process. More expertise in stressing electronics, and standards for it, would benefit the whole e-textile industry significantly.
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