Power management as a challenge to the wearable medical devices design

This article will discuss the ways of using both new and established power management platforms to optimise the design of wearable medical devices. By Christian DeFeo, eSupplier Manager, Newark element14.

Bluetooth 4.0 & BLE

One of the Sudden Impact competitors, Hendrik Lipka, has been looking at various Bluetooth protocols for his helmet-mounted impact and heart-rate monitors for skiers and footballers. The terms Bluetooth 4.0 and BLE are often used interchangeably but Hendrik found how different the two standards are when applied into the wearable medical device design.

Bluetooth 4.0 is a relatively new type of wireless technology, offering considerably lower power consumption versus previous standards. It is a combination of three different protocols: Bluetooth Classic, Bluetooth High Speed and BLE. With the exception of their data transmission processes, Bluetooth Classic and Bluetooth High Speed are pretty much the same. BLE, however, is designed for extremely low power devices and works best for short lived, low-data transmissions.

The theory has been proven in Henrik’s device design process: Hendrik discovered that BLE is particularly useful for the transmission of real-time information. Hendrik’s heart rate sensor could therefore capture an athlete’s heartbeat as a ‘current state’, alongside the minimum and maximum values within a specific time frame. As such, BLE proved itself to be an appropriate protocol for athletes that want to use the heart-monitor as a safety measure and be notified of irregular heart rates. However, for continual monitoring, BLE is not ideal and sheds light on the functionality vs. longevity battle that engineers are constantly grappling with.

Wireless charging

Another of the design challenge participants, Douglas Wong, has been trialling wireless charging as a solution to powering his helmet-mounted trauma monitor for hockey players. He used Qi charging, a global standard developed by the WPC that enables any device with a compatible battery to be charged from a wireless pad, using induction transfer.

Douglas’ device, with an embedded Qi charger, provides a simple solution for hockey team managers. By using a handful of Qi charging pads, the entire team’s helmets could be fully charged before a game which would consequently ensure the safety of every player on the pitch.

While Qi charging has been proved as a concept, in order to prove its functionality in practice, the Qi system needs to be implemented on a significantly larger scale.

This seems to feed in to a wider issue with current wireless power solutions. Due to the stringent requirements and guidelines governing wearable health devices, the technology is not yet ready for widespread usage in the sector. The approaches that our finalists have taken highlight the need for more data-intensive technologies that can relay large quantities of data for long periods of time.