Role of MCUs in wearable electronics

August 19, 2016 // By Vairamuthu Ramasamy and Sivaguru Noopuran
Wearable technology is the buzz word now in the consumer electronics industry. Every consumer electronics company is talking about launching one of these wearable devices. These are miniature electronic devices that are usually worn by us, often integrated with or designed to replace the existing accessories such as a watch.

With the current revolution in the wearable device’s industry, the need for smaller, more intuitive devices is rapidly increasing. Some of the current trends of devices that we are seeing in this new industry are the smart-watches, smart-glasses, sports and fitness activity trackers. Apart from consumer electronics, it is also creating an interesting demand in the medical industry.

It is obvious that electronics that goes inside these devices need to become smaller than they used to be. The most important electronic component would be the microcontroller. As these MCUs need to be small and also perform more functions, integration becomes another important factor. In this article, we will be looking at,

  • The different requirements for a wearable electronic system
  • How the market can be segmented based on the requirements
  • Different components in a typical wearable device
  • And finally we will take a look at how MCUs can help address these requirements


Requirements of Wearable Devices


The most important requirement in a wearable device would be the aesthetic factor. The end-product needs to be stylish, fashionable, and they need to blend with the existing fashion accessories such as ornaments, watches, glasses etc. The fact that the top semiconductor companies such as Intel partnering with the fashion industry to make these devices fashionable tells us why this requirement is very important.

Capacitive touch sensing is a key technology that enables improving the aesthetics. Important requirements for the capacitive UI here will be to be able to work on a variety of form factors including curved surfaces, to be tolerant liquids, and to be able to sense under thick overlays. Cypress’ CapSense and TrueTouch technologies make such requirements practically realizable.


The requirement for these devices is to be small in size so that they can easily fit on to a wearable. Nevertheless, the features that they exhibit shouldn’t be reduced or minimized. So the components used in these devices should be small in size and at the same time integrate more features in the same space. Technologies such as System-on-Chip (SoC) and chip scale packages (CSP) help to shrink the size.

Water tolerance:

Wearable devices are going to be everywhere where the human-body can go. Therefore it is important to design these devices to be tolerant to the environmental conditions such as water droplets, moisture, sweat etc.

Power consumption:

Wearable devices are battery powered devices, reducing the power consumption of these devices poses unique challenges due to the following factors.

  • The wearable devices unlike other mobile devices are required to be always on and always connected because most of these are monitoring devices. For example, a smart watch needs to be always showing the time, be connected to a mobile phone through a wireless link such as Bluetooth, required to continuously count steps and report it back to a device and much more.
  • Battery capacity is inherently limited due to the requirement to reduce the overall size

These devices need to operate at ultra-low power to conserve the battery life. This requirement drives special needs in MCU and firmware algorithm. 32-bit ARM architecture is a popular CPU technology for wearable devices as it provides best performance and energy efficiency. Also wireless technologies such as ANT+, Bluetooth Low Energy (BLE) are designed to consume low power.

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