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WEARABLE & IMPLANTABLE ELECTRONICS increasing consumer resistance to the need to carry their phone when they are using a wearable. Simply adding a cellular connection to a smart watch or other device to replace the separate phone is rarely a good solution due to the impact on size and battery life. With the number of connected devices increasing exponentially, the number of necessary connection points naturally increases, ultimately expanding the overall density of the network. Although this offers the potential for alternative connection technologies, existing UHF standards such as Wireless HD and WiGig are not appropriate as they were not designed to support such a huge array of connections. Engineers typically respond to the challenge of eliminating tethering by designing in Wi-Fi or Bluetooth connectivity as integral components for wearable devices. However, even when using low power connectivity such as BLE, this constant need to remain connected has a huge impact on power consumption, which is our next barrier. Who’s got the power? With Wi-Fi or Bluetooth connectivity coming as standard on the majority of wearable devices today, this constant connectivity increases power consumption. End users feel duty bound to own the latest product and the more they do so, the more power is needed. With battery technology failing to keep pace with power requirements, and consumers demanding smaller, sleeker and more attractive wearables, it’s not possible to simply use a larger battery. Design engineers have understood this challenge and have turned to wireless charging for a solution. Nikola Tesla first demonstrated wireless power transmission in 1891, when he succeeded in lighting electric lamps without wires. It took more than a century before this technology became more mainstream but in recent years it has emerged onto the consumer electronics market with the likes of supermarkets and coffee houses offering charging stations and retailers offering wireless charging kits for the home or office. Aside from the obvious benefit of removing the need for charging cables, wireless charging has the benefit of being more durable as well as and more eco-friendly through the elimination of electronic waste and energy transfer is non-radiative. However, even with these benefits there are some disadvantages to wireless charging. It can be more expensive, less efficient and slower than traditional wired charging, although newer approaches aim to reduce transfer losses and improve speed through the use of ultra-thin coils and higher frequencies. Recognising the need for improved solutions which would positively impact adoption of wearable devices, consumer electronics companies, as well as manufacturers from the semiconductor, mobile services, automotive, furniture, software and others industries, have joined the drive to improve wireless charging. As with many other new technologies, however, there are competing approaches to wireless charging. Currently there are three organisations that are competing to standardise wireless charging technologies: The Wireless Power Consortium (WPC) with its Qi standard, the Power Matters Alliance (PMA) and the Alliance for Wireless Power (A4WP), presenting product developers with a dilemma of which standard to choose. How can we address data privacy? Although these devices are small, wearables hold and facilitate communication of a vast amount of very personal data. With so much data sharing between devices and the cloud or servers, security breaches are a huge concern to both consumers and brands. The WaRP7 rev2.0 development board. As the connected world expands, increased data privacy legislation could be on its way as countries across the globe pass new laws to keep up with the growth of connected technologies. According to Deloitte, there were approximately 20 privacy laws globally in the 1990s and today there are more than 100. The good news is that there are already a number of trusted vendors who can help mitigate the risk of security problems along with proven technologies like end-to-end encryption and token-based authentication that are suited for IoT applications. While software security is the focus of a lot of attention, embedded security is also an important consideration for design engineers. The use of development boards such as the WaRP7 that includes a built in NXP processor, makes designing with embedded security in mind incredibly straightforward. So, are we nearly there yet? Whilst wearable technology has come a long way in recent years, the industry still needs to undertake significant development, if mainstream consumer adoption is to become a reality. The IoT is a busy place and designers do face some tough challenges in order to meet consumer demands and allay fears, but the tools and the support for designers are available through strategic partners who can offer the right resources. www.electronics-eetimes.com Electronic Engineering Times Europe March 2017 45


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