There are clearly big expectations for wearable technology and though we have already started to see its proliferation into our everyday lives, to some degree at least, this sector is still just coming out of its nascent stages. According to a report published last month by analyst firm Scalar Market Research wearable technology shipments currently represent a healthy $29.9 billion in revenue, but it expects this to experience a 18.9% compound annual growth rate (CAGR) over the next 5 years, attaining a figure of $71.2 billion by 2021. A large proportion of this will be made of up smartwatches and fitness trackers.
Though wearable technology can, in principle, take many different forms, there are certain core attributes which are present throughout. For engineering teams engaged in wearable design projects, these can serve as a useful guideline on which to base their work.
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Low power operation will effectively be mandatory for any item of 
wearable technology, so this needs to be reflected in every element of the development process. If the product has too heavy a drain on its battery reserves, then it will prove inconvenient to the user and they will be less keen to wear it. To ensure that they are informed of the remaining battery charge, an accurate measure of this parameter should be readily accessible to the user.
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Based on the previous point, inclusion of wireless charging functionality is certain to be of value. Through this there can be provision for the item of wearable technology to replenish its energy reserves whenever the opportunity arises.
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At the heart of the design should be a power efficient processor that is capable of supporting a multitude of features and delivering strong performance without impacting too greatly on the battery charge.
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Given that the item is going to be attached in some way to the user’s body, a sleek form factor and lightweight construction are both likely to be appealing, as this will mean that it is more comfortable to wear.
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Wireless connectivity is a vital feature for wearable technology (so that data or multimedia content can be transferred to and from it). For the reasons already highlighted, this should be optimized for battery operation. Bluetooth Low Energy (BLE) is proving to be a popular connectivity option as a result.
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A power efficient human machine interface (HMI) is likely to be needed, so that information can be referred to (such as training performance statistics) or control functions undertaken. The level of sophistication of this HMI will depend on the nature of the applications that the item of wearable electronics is designed for.
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A collection of different sensors will normally need to be incorporated, so that relevant data can be acquired. Wherever possible the use of MEMS-based sensing technology is preferable, as this approach will help to conserve battery charge (since such devices draw less power) and also allow more streamlined wearable designs (given their compact dimensions).
Though much of the sector has so far been dominated by the large players, as it matures there are certain to be a growing number of opportunities for smaller OEMs to tap into the potential of wearable technology. The level of support that such companies need is very different however. Large OEMs have far greater engineering capabilities at their disposal. As a result they can build wearable designs from the ground up. Their smaller counterparts simply don’t have that luxury. They need to be able to utilize development solutions that will give them a head start on their projects - enabling them to bring differentiated products to market at an accelerated pace, but without relying on heavy engineering investment.
As it has expertise that spans a broad range of different electronics disciplines, ON Semiconductor is very well positioned to address the diverse demands that are associated with wearable technology. Our new Wearable Development Kit (WDK1.0) is a direct response to the needs of smaller OEMs for a more comprehensive development platform.
Complemented by an Eclipse-based IDE, WDK1.0 provides a highly scalable, multi-faceted platform that encompasses all key the aspects previously outlined, so the development of advanced wearable products can be accomplished. Incorporated into this design resource is an nRF52832 multi-protocol system-on-chip (SoC) with a 32-bit ARM® Cortex™ processing core and a 2.4GHz transceiver suitable for BLE (as well as supporting the various other wireless protocols in this frequency band). There is an NCP1855 battery charger IC, a LC709203F fuel gauge IC and an AirFuel-compatible wireless charging front-end controller as well as a NCP6915, high efficiency programmable Power Management IC that provides 5 LDOs and 1 DC-DC to support power requirement for the smartwatch and for additional development requirement. In addition, it has a MEMS-based FIS1100 inertial measurement unit, which comprises a 3‐axis gyroscope and a 3‐axis accelerometer, for multi-dimensional motion tracking. There is also an embedded temperature sensor, plus an LC898301 driver IC for haptic feedback purposes. A useful SmartApp (which can be downloaded directly from Android PlayStore and AppleStore) facilitates the construction of HMIs onto the WDK1.0’s 128x128 resolution TFT display (which features a capacitive touch screen). The Project Wizard further expedites wearable development by furnishing engineers with helpful project examples.
