Design Challenges for Wearables

Editor’s Note: This article first appeared in ecnmag

This holiday season, most of my friends/family received some form of wearable device as a gift. Even my 84-year-old dad is joining the wearable bandwagon and is finally giving himself what should probably be termed the original “wearable” — a hearing aid.

As executive director of MEMS Industry Group (MIG), the trade association advancing MEMS and sensors across global markets, I, too, have a sensors- and micro-electromechanical systems (MEMS)-laden wearable device that silently sits on my wrist and somewhat accurately counts my steps and tracks my sleeping habits. I long for the day when I can have a wearable that is seamless and elegant as it counts my calories (in and out), accurately assesses my health, and which harnesses energy from the vibrations created through my own movement.

So how far off is this wearable Utopia? To get a reading on what it takes to design wearables for consumer success, I asked a few of the experts in the MEMS/sensors supply chain who eat/sleep/pray in the wearable device tech world and will be joining me at MIG’s MEMS and sensors conference on wearables at the 2015 International CES on January 6.

Wearable devices represent one of the fastest-growing market segments in consumer electronics. They rely heavily on technology from the MEMS/sensors supply chain in order to track activity, interpret motion and augment reality. But designing for these space-constrained devices — which must be low power and increasingly packed with functionality (we’re way beyond just step-counting these days) — is not without its challenges.

Tim Saxe, CTO of QuickLogic, believes that “the top issues depend on whether the developer is thinking of a wearable device without a display or one with a display…For devices without a display, the top challenge is how to get really, really long battery life. The goal seems to be six months minimum, with one year preferred.”

Saxe elaborated that “for devices with a display, the challenge is control, and people want non-touch ways to control the device. How to make this ‘intuitive’ i.e. convenient, repeatable and easily discoverable, is an emerging area so people have lots of ideas and need to quickly try them out and refine them.” For me this brings visions of Google Glass vs. Jawbone UP vs. Apple iWatch: Everyone is placing bets on what form factor and design will win this race. And it reinforces my belief that for a wearable to be successful in the marketplace, the user needs to be unaware that he/she is actually wearing it.

Several folks pointed out that a key issue for wearables is that each time a user has to take them off or can’t use them is a chance for the user to lose interest. At this point, that device could “end up in the sock drawer,” said Dr. Steven LeBouef, president of Valencell.

Seppo Nissilä, CEO of SilverBlip shared with me his list of pain points, which include technical challenges. “Low-power and small form factor do not happen without many design rounds,” said Nissilä. He also called out a warning shot regarding validation/compatibility/IP challenges “that are often underestimated in small companies and big ones, too.”

When I asked David Allan, president of Virtuix, what keeps him up at night, he said, “In the MEMS field, the mobile phone is the ‘big boss.’ Yet most startups aren’t designing phones. When you try to design something different, like wearable motion sensors for virtual reality, you immediately hit a roadblock: the fusion software that comes free with sensor devices caters to the needs of the phone. It fails to capture complex translational and rotational motions that differ from typical phone applications. So you need to customize the fusion. But then, you find out that custom software costs maybe six or even seven figures to develop…and you’re stuck. We got lucky and found ex-InvenSense engineers to develop our fusion. But many startups, lacking contacts in the sensor industry, won’t know how to proceed. One encouraging development on this front: MIG’s open-source algorithm cooperative, the Accelerated Innovation Community (AIC), which includes an open-source C library for 3-, 6- and 9-axis sensor fusion.”

Becky Oh, board member of PNI Sensor Corporation, identified power consumption as one of the most pressing challenges of designing wearables. “As space-constrained devices, batteries must be as small as possible – so every microamp of power consumption is critical.”

And Oh believes that sensor fusion is a big part of the solution to the power issue. “Since these devices will use sensors for always-on monitoring, there need to be hardware and processors that are optimized specifically for sensors and sensor fusion algorithms, such as intelligent sensor hubs or sensor coprocessors. These sensor coprocessors have architectures that are optimized for sensor-related algorithms and interfaces, making them much lower power than a general purpose processor.

The second major challenge, according to Oh, is value added data analysis. “At the hardware level, capturing the raw data accurately is key, but in order to achieve this in the design phase, you need hardware development platforms that are form-factor ready — essentially requiring you to build the wearable before feasibility studies are completed.”

Valencell’s LeBoeuf had another major challenge in mind, one that relates closely to his company’s biometric sensor technology: “The advent of I2C MEMS and sensor solutions made our biometric signal extraction technology a lot more scalable for OEMs. But I2C optical sensor solutions were geared towards proximity detection — not biometric sensing. For this reason, additional microprocessor resources were required to make up for suboptimal sensing — draining battery life and limiting our market opportunities.”

LeBoeuf ultimately overcame this problem “by working with silicon solution providers early in the process, teaching them what changes needed to be made in order to keep accuracy high while maintaining high battery life.”

Though these challenges may seem insurmountable, on the bright side, it’s clear that my colleagues are well positioned to both name and address them. My guess is that in the next year or two, we’ll see some of those seamless, elegant wearable devices packed with functionality that I now dream of.

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