Svenn-Tore Larsen, CEO, Nordic Semiconductor

Wearable devices promise to become big business, but without a merger of compact efficient electronics, ultra-low power wireless technology and smartphones that potential would remain unfulfilled.

In 2006, Nike, the U.S.-based sportswear company, launched one of the first massmarket speed and distance sensors which, when attached to a sports shoe, recorded how far and fast the user ran. The “Nike+iPod Sports Kit” was forged from a collaboration between Nike and Apple and comprised an Apple iPod, a wireless sensor, Nike shoes that accepted the sensor, and an Apple iTunes membership. It was one of the earliest examples of a “wearable electronics” device.

The next year, Wired journalists Gary Wolf and Kevin Kelly launched the Quantified Self website, which encouraged bloggers to upload stories about how they used “self-tracking” tools like the Nike product to collect data-such as temperature, heart rate, calories consumed, and weight-and how they then extracted meaning from those data to improve their well-being.

Figure 1. Keen exercisers have enjoyed the benefits of wearable products such as HRMs and sports watches for over a decade.

Figure 1. Keen exercisers have enjoyed the benefits of wearable products such as HRMs and sports watches for over a decade.

Back then, wearable electronics were targeted at fitness gadget early adopters and used niche technology. But today, wearable devices have become the latest hot toys for the mass market. Research firm MarketsandMarkets, estimates the “global wearable technology ecosystem’s” value will reach US$14 billion by 2018, growing at a compound annual growth rate (CAGR) of more than 18 percent from 2013 to 2018. The current level of penetration of the forecast “total available market” for wearable technology is estimated to be 18 percent, accelerating over the next five years to reach 46 percent by 2018.

The catalyst for the sector’s explosion is the convergence of several previously unrelated technologies. By combining these technologies, engineers have designed a whole new breed of electronic devices that can be carried unobtrusively on a person.

Tiny electronics chips that can run from batteries as small as those used in a wristwatch allow tech companies to offer products such as compact sensors. These products, thanks to smartphone compatible wireless technology, communicate seamlessly with the handsets in consumers’ pockets or the tablet computers in their bags. Also, a range of inexpensive apps can collect, analyze and present the information gleaned from the sensor in a user-friendly-format indicating. For example, how far the user needs to walk to burn off last night’s burger and fries. The data can then be uploaded to social networks to inform the user’s friends of their progress and promote healthy competition.

But where have these technologies come from? And why is it only now that they have come together to propel this exciting new gadget sector?

Eking out the power

The term “wearable electronics” covers a range of devices from computers such as Google Glass, smart watches, fitness bracelets and heart rate monitors to lowly pedometers. Some of these products feature color displays and functionality, such as GPS receivers, and will therefore require the resources of rechargeable Li-ion batteries. But a growing proportion of wearable devices, particularly compact sensors, are designed to be light and unobtrusive. This limits space for a battery, yet products are expected to operate for months or even years without cell swaps.

Figure 2. The latest wearable devices, such as these 3-D pedometers from HMM Diagnostics GmbH, are designed to be light and unobtrusive. (Courtesy HMM Diagnostics GmBH)

Figure 2. The latest wearable devices, such as these 3-D pedometers from HMM Diagnostics GmbH, are designed to be light and unobtrusive. (Courtesy HMM Diagnostics GmBH)

The tiny power-efficient chips that provide sufficient computational muscle, yet can run off small batteries for long periods, are one of the key technologies behind the wearable electronics revolution. Engineers didn’t set out to design these chips specifically for wearable electronics; rather they came up with them in order to make the most out of the relatively puny batteries used in the first generations of portable computers, cell phones and personal digital assistants (PDA). Squeezing just a few hours out of these early rechargeable cells demanded some novel silicon design.

One way that engineers improved the efficiency of silicon was by integrating more functions onto a single chip. For example, instead of using separate memory and microprocessor chips and then linking them together using the tracks on a printed circuit board (PCB), the devices were “embedded” onto the same slice of silicon. Embedded microprocessor and memory devices consume far less power than equivalent discrete chips on a PCB. An added bonus is that embedded devices take up much less space—an important advantage considering the Lilliputian internal dimensions of many mobile devices. It should come as no surprise to learn that embedded electronics technology was rapidly embraced by cell phone industry; for example, embedded processors based on intellectual property (IP) from U.K.-based ARM power the majority of the world’s mobiles.

To keep power consumption down, Nordic Semiconductor employs similar high levels of integration in its latest generation of wireless chips. These devices embed an ARM processor, 2.4GHz silicon radio and flash memory onto a tiny slice of silicon measuring just 3.5 by 3.8 millimetres – making them a good choice for wearable applications.

Since the first generation of portable devices, batteries have steadily improved. However, along with that improvement has come an expectation from consumers that each new generation of handhelds offers more functions but with longer battery life—ensuring the engineer’s battle to design chips that conserve power continues unabated.

A second technology essential to (and stimulating) the rise of wearable electronics is the proliferation of portable, Internet-enabled computers, otherwise known as a smartphones and tablet computers. In the next several years, sales of these devices are forecasted to surge. Analyst Statista Research estimate there will be a cumulative total of 6.1 billion mobile devices globally by 2020.

Two factors have put mobile devices at the centre (literally and figuratively) of the wearable electronics revolution. First, mobiles will form the “hubs” that provide the processing power to collect and make sense of data coming from a personal network of wearable devices, then analyze, present and share that information. Second, the current generation of tech-savvy consumers have grown up with the smartphone and expect it to link seamlessly with other gadgets they buy so it can be used to control them.

The final technology that’s driving the wearable electronics sector is wireless connectivity. Without this connectivity, body-worn devices would be forced to operate in isolation, greatly limiting their potential. The wireless link enables either a connection to a Wi-Fi bridge and from there to the Internet, or to the smartphones carried in virtually every consumer’s pocket. In the latter case, the link allows the wearable electronics product to leverage the smartphone’s powerful microprocessor, large color touchscreen and downloaded app software.

Culmination of a vision

For almost a decade, manufacturers such as Nordic Semiconductor have specialized in a form of wireless connectivity that can operate from watch batteries. Known as ultra low power (ULP) wireless, the technology was originally conceived to fill a niche missed by other radio frequency (RF) products such as Wi-Fi, Bluetooth wireless technology and ZigBee. Target applications included computer mice, keyboards and sports watches. This latter product functioned as the “wrist-top” computer linked with heart rate monitors (HRM) and speed & distance sensors beloved of the technology early adopters described above.

Back in the early years of this millennium, smartphone manufacturers, particularly Nokia, realized that one way to keep their products as the focus of consumers’ “digital lives” was to allow them to wirelessly connect to “peripheral” devices or “appcessories” (such as HRMs) with ease. A decade later, the culmination of this vision sees most high-end mobiles incorporate as standard the latest form of Bluetooth wireless technology (and/or a competitive technology called ANT+). (Both Bluetooth wireless technology and ANT+ provide robust, interference-free wireless communication in the licence-free 2.4G-Hz Industrial, Scientific, Medical (ISM) part of the radio frequency (RF) spectrum.)

Moreover, because major technology companies such as Apple, Google and Microsoft have announced “native” support for the latest version of Bluetooth technology it has become much easier for engineers developing wearable electronics to create the companion smartphone-based apps that allow products to fulfill their function.

The custodians of the Bluetooth standard, the Bluetooth Special Interest Group (SIG) market the technology in two types: “Bluetooth Smart” is the low power version (formerly known as “Bluetooth low energy”) and “Bluetooth Smart Ready” is a compatible version with similar capabilities to the previous version of Bluetooth technology together with some key enhancements.

Bluetooth Smart Ready products such as smartphones can link quickly and easily—without any additional equipment of technical knowledge of the part of the consumer—with wearable electronics equipped with Bluetooth Smart. Bluetooth Smart requires very little battery power, helping conserve the life of the host wearable device’s small-capacity cell and is based in part on ULP wireless technology pioneered by Nordic Semiconductor.

Wearables puzzle complete

Despite the hype, the wearable electronics sector isn’t new. Early technology adopters, especially those interested in keeping fit, have enjoyed the benefits of wearable products such as HRMs and sports watches for over a decade as power frugal electronics and ULP wireless connectivity were the key technologies enabling this sector. Wearable devices could well have remained a niche sector without the foresight of companies like Nokia that realized the benefits of wearable sensors that could communicate with mobiles without additional purchases and requiring only minimal user set-up.

Figure 3-Nordic

Figure 3. The Cookoo from Connectedevice is an example of the new generation of wearable electronics that link seamlessly to smartphones. (Courtesy Connectedevice)

The incorporation of Bluetooth Smart (and/or ANT+) into mobile devices as a standard fitment was the final piece of the wearable
electronics puzzle. Now the technology is ready for the mass market and in a pleasing symmetry, the sports watches that helped launch the sector have morphed into the smart watches that are proving to be the flagship products propelling it into the mainstream. Another nice symmetry, both Nike’s 2006 speed & distance sensor and many of 2014’s smart watches (such as the Cookoo from Connectedevice) employ wireless technology from Nordic Semiconductor.