Get Ready For The Next Generation Of Wearable Tech

Wearables have attracted a lot of attention recently, due to both their successes as well as failures. They bring together requirements for packaging, new substrates, power scavenging, low-power, novel connectivity, flexibility, durability, as well as fashion.

While some of the challenges remain formidable, the long-term potential is driving the industry to look at what is possible. They are preparing for the day when technology can deliver what creative minds have in store for it.

We have become used to fitness trackers and smart watches. Smart glasses are presenting more of a challenge, but present a lot of opportunities. Smart shoes are a thing in the athletic world. But the ultimate goal for many is to embed smarts into the clothing itself or items placed directly on the skin. In addition to sensors, this could include everything from actuators, color changing surfaces, or the application of pressure for better posture, to the regulation of medicines and much more.

One of the challenges for many wearables is providing enough value, or being convenient enough to use. Even fitness trackers are seen as providing significant initial value that is not persistent. The gains induced by the device subsequently go by the wayside and the devices get discarded. Because of this, some devices may be engineered to be short-term.

“Wearables must be relatively low-cost, lightweight and comfortable for all-day wear,” says Srinivas Pattamatta, vice president at Atmosic Technologies. “Theme parks are rolling out wearable devices for a more interactive user experience when visiting the parks. These devices can also enable COVID-friendly practices, such as touchless ticketing and locking and unlocking lockers, and avoiding contact with potentially contaminated surfaces.”

Part of the problem may be forcing existing technology to be used rather than developing technology specifically for the required task. “I would characterize the wearable market as providing top-down solutions,” says George Sun, CEO of Nextiles. “That is, using solutions made from other industries and repurposing them for the body. An example is the accelerometer, primarily used for aircrafts and moving vehicles, but now miniaturized to be used as a step counter for humans. This has allowed reverse engineered attachment mechanisms, through straps, adhesives, insoles, glasses, etc. In my opinion, these solutions are functionally wearable, but not truly wearable in the literal sense.”

Smart glasses are seen as a high-cost, high-value potential market. “Despite being the toughest to achieve in engineering terms — largely due to the power and performance considerations of the small and lightweight form factor — the future of augmented reality (AR) wearables is likely to be smart glasses,” says Ketan Shah, senior director of XR and wearables at Arm. “Arm’s own consumer research shows that 58% of those surveyed are positive about the prospect of wearing everyday AR smart glasses, with this encompassing a variety of use cases, from immersive gaming and screen projection to navigation and translation ‘on-the-go’.”

It requires a technology convergence. “There are many pieces that have to come together,” says Frank Schirrmeister, senior group director for solutions and ecosystem at Cadence. “It requires advanced packaging, advanced sensor and sensor fusion technology, attention to issues like security, and it must seamlessly work and provide value.”

Given the limited amount of battery power available for wearables, this is harder than it looks. “It requires thinking about not just products, but about systems and solutions,” said Shawn Slusser, senior vice president of sales, marketing and distribution at Infineon Technologies.

As with many such devices, there needs to be a balance between wasting energy by providing too much capability, or increasing battery life but ending up with a system that’s not really sophisticated enough.

Some of the necessary pieces are not there yet. “Surprisingly — or some may say ironically — the limiters are the boring parts of the technology,” says Nextiles’ Sun. “How are we going to charge the device? How is the device going to communicate? And can it communicate through the plastic or clothing? How is the device going to interface with my clothing or body? Is it through another strap, directly embedded in the clothing, something magnetic, etc.?”

And it has to be at the right cost point. “As ultra-low-cost microprocessors become commercially viable, all sort of markets will open with interesting use cases, such as smart sensors, smart labels and intelligent packaging,” said John Biggs, distinguished engineer for Arm Research in a recent statement. “Products using these devices could help with sustainability by reducing food waste and promote the circular economy with smart life-cycle tracking. Personally, I think that the biggest impact could be in health care — this technology really lends itself to building intelligent disposable health monitoring systems that can be applied directly to the skin.”

The value of data
Part of the problem is that many of these devices produce lots of data, but what do you do with it? Data that cannot be translated into actionable information has little value. “The smarts are in the aggregation of data,” says John Stabenow, director of product engineering for Siemens EDA. “This is likely not in the devices, but in some application that receives the data.”

That sometimes can require bringing together many disparate pieces of data. “In one of my devices, the data is transmitted and computed in the cloud,” says Cadence’s Schirrmeister. “They give you insights about how you’re progressing towards certain goals, keeping a log of what have you done, and then it may tell you that if you worked out late at night, if it had an impact on your sleep.”

Schirrmeister points to Facebook’s new Project Aria. “They are essentially looking at smart glasses, but they’re looking at it from a data perspective. They are also considering privacy analysis. For example, they have these standard examples where somebody is basically going through their apartment and the captured images are getting rendered, and it is recognizing things. Things like faces may be greyed out, but sometimes you may want this data. If you say to it, ‘I lost my keys’, they will figure out where they are, based on where they were last seen by the glasses — on the coffee table in the guest room.”

Health care
The highest value probably comes from the health care industry, where there is a direct incentive to wear the necessary devices, clothing, patches, etc., and the ecosystem is established to fully analyze the data. “Wearables and other connected devices are being used for a variety of medical applications and delivering regular, always-on data that can be pivotal to a patient’s health,” says Atmosic’s Pattamatta. “Wearable medical devices have given patients and the medical staff taking care of them an easy way to monitor their vitals and detect issues before they become serious problems. One emerging use case for wearable medical devices is continuous glucose monitoring (CGM), a relatively pain-free way to track the real-time effects of food and exercise on one’s blood glucose levels.”

Today’s CGMs are specialized devices that require frequent battery changes and regular replacement of sensors. Being able to use another device, such as a smart watch, to track glucose levels using a non-invasive sensor is considered a huge opportunity for smart watch developers, and one that so far has been difficult to achieve with enough accuracy.

Accuracy of data remains a challenge in the wearables market, as reflected in the number of false positives and negatives. “Accuracy comes down to having good sensors,” said Infineon’s Slusser. “With false sensing you get poor data, so the key for semiconductors is bringing up that accuracy. With sensor fusion, you can combine the output of multiple sensors, so even if one sensor is telling you one thing, multiple sensors can validate that data. That wasn’t affordable in the past, but now it is.”

These sensors also need to be able to output data quickly enough to be able to make an impact. “Health devices have come along way, both the hardware and the application of the data for use in our lives,” says Siemens’ Stabenow. “An example is the Oura sleep monitoring ring and application. This is a great example of combining the technology and a user experience that can add value. Another application could be to record and monitor body mechanics or body movement. Imagine a physical therapists office setting, where they can use a smart suit to assess a patient’s mobility and measure the patient’s shoulder range of motion. The doctor can then prescribe stretches and exercises designed to improve range of motion. The suit can record the patient as they do these movements, and offer feedback on how to improve, or how to avoid putting the arm and shoulder into positions that are incorrect or detrimental to the goal.”

But there remains a non-technical problem. “There’s a trust issue,” says Schirrmeister. “What we found is that people generally don’t trust these devices, depending on the type of illness. We conducted a survey of 3,000 users worldwide. Only 30% said they were comfortable with an AI device-based diagnosis of many serious issues (see figure 1). But people are getting more confident with these technologies, because it makes it so much more convenient for them. It is the three Cs — confidence convenience and then collaboration. Instead of just trusting my device, experts look at it as one data point that may show things to keep an eye open for.”

Fig. 1: Percentage of people comfortable with diagnosis from a wearable. Source: Cadence

Technical issues
There are many technical issues that have to be solved. In some cases that just means improving the existing technology, but in other cases it may require a more fundamental rethink.

Circuitry on fabric has been making some advances. “One very narrow and specific space will be in smart fabric — wearable fabrics with built-in electronics and sensors,” says Stabenow. “The obvious application is health, where the clothing offers a much broader opportunity for data collection. But there are many ways that wearable fabrics go far beyond the typical health application of monitoring vital signs and blood chemistry.”

Others agree. “We will inevitably move towards more flexible and form-fitting substrates to cater to the growing demand and technological advances in the wearable space,” says Nextile’s Sun. “Currently, this substrate has been silicon and similar semiconductive metals. New substrates are soft material technologies. The soft materials we use are textiles, fabrics, but we see other companies using plastics, gels, biofilms, etc. We decided to pursue textiles as our wearable vehicle, because fabrics are what we already wear, and statistically (fun fact), 95% of our bodies have, or will have, interacted with a piece of fabric at any given time.”

Arm recently announced success using plastic as a substrate. “PlasticARM will pioneer the development of low-cost, fully flexible smart integrated systems to enable an ‘internet of everything’ consisting of the integration of more than a trillion inanimate objects over the next decade into the digital world. Having an ultra-thin, conformable, low-cost, natively flexible microprocessor for everyday objects will unravel innovations leading to a variety of research and business opportunities,” according to the company.

To make this work, packaging needs to be re-thought. “Look at the funky way that the Facebook Aria is assembled,” says Schirrmeister. “Think about what that means for packaging technologies and sensor technologies. Think about how all the data is connecting and then where things are processed.”

New fabrication technologies also will be required. “We need to re-engineer sewing machines and textile equipment for wearable production,” says Sun. “Not only have we added or created new machines for the market, but we are also building a new ‘language’ of sensor technologies that can communicate via threads. These sensors require different construction methods, and these construction methods follow patterns and architectures unique to the industry.”

Size and accuracy are important for the sensors. “Sensor size will be an issue,” says Stabenow. “To be accurate, there would need to be hundreds or thousands of sensors collecting data. And while MEMS miniaturization is happening, there is still a long way to go to be small, light, and truly wearable. Accuracy will be another issue, which a quantity of sensors may overcome. All sensors will need to talk to each other to create a mesh, and it is less likely to be by hard wires than by some wireless connectivity.”

Some processing is likely to happen within the devices. “More than 90% of our smarts come from the soft-goods, and the ‘hubs’ or pods, as we call them, are the messengers,” says Sun. “These are taking signals from the soft-good and directing them to a local device such as a phone or computer via Bluetooth.”

Pattamatta also sees new Bluetooth development as an important step. “The implementation of Bluetooth 5.0 is helpful for wearables, given the importance of standards-based connectivity. Bluetooth 5.0 in wearables helps extend the battery life by decreasing its power consumption an impressive 5 to 10 times.”

Power is a pivotal concern. “What lies in our future is how to take advantage of kinetic motion to charge our devices,” says Sun. “That is, if a device is worn, can it be simultaneously charged by motion from the body, such as the bending of the knee or movement of the arm? Kinetic charging will be a revolutionary technology that can assist in miniaturizing and optimizing wearable tech.”

Other types of energy harvesting are being considered. “Various forms of energy harvesting techniques are possible,” says Pattamatta. “One candidate is photovoltaic. This would have the ability to harvest indoor light sources and could extend a device’s battery life considerably. Energy harvesting is an ideal solution for wearables since energy harvesting can enable batteries to last the entire lifetime of a device, making it easier and cheaper to manage fleets of these devices.”

But electronics has a nemesis — water. “We get asked repeatedly about the robustness of the materials,” says Sun. “How many times can we wash the device? Can it survive exposure to the sun, liquids, bodily fluids, etc.? The best way to surpass these limiters is to test, and to test consciously. This means engaging the public, listening to their opinions and suggestions on aesthetics and comfort and form-factor, and building solutions that directly address those problems.”

Conclusion
Wearables in the form of watches have crossed the threshold of affordable devices that provide sufficient functionality and are practical with the technology that exists today. Smart glasses may be nearing that threshold. But to get to the total ubiquity of wearable clothing will require significant advances and it is most likely that medical will be the spearhead that makes this possible. But they will have to prove themselves first, and getting completely sanctioned medical devices is a long and costly process. Using them to supplement data gathering may be a good start.