Solving thermal complications in wearable tech

As technology becomes smaller, smarter, more sophisticated and synchronised, the demand for wearables has risen. The primary market drivers for wearables continues to be watches and wristbands – its two most popular categories. However, its offerings are also becoming more and more diverse, with various companies producing glasses, fitness trackers, heartrate monitors and Virtual Reality (VR) headsets.

Whatever form the final product takes, consumer expectation is that wearables should be lightweight, compact and comfortable. For design engineers, this makes the issue of thermal management a complex problem to solve.

Firstly, unlike other low-powered devices, manufacturers are forced to operate within a confined space. The challenge is to squeeze components into ever smaller and thinner spaces, without compromising functionality. Today, smartwatches for example, must do far more than just send and receive messages, they must play music, make video calls, send emails and support WiFi. With each of these functions comes additional power requirements, and additional power results in greater heat output.

The complications presented by the size, portability and the high functionality of wearables means that installing often bulky cooling systems is virtually impossible. In some cases, design engineers assume that, given the low powered nature of the device, it is unlikely to overheat. According to research conducted by 6SigmaET, over a quarter of design engineers don’t test the thermal properties of their devices until after completion. The failure to acknowledge the potential for thermal complications early in the design process can have serious consequences further down the line.

Last year, Intel was forced to issue a total recall of its Basis Peak smartwatch due to an unexpected thermal complication. While only 0.2% of watches suffered from the overheating issue, the fundamental flaw was so deeply ingrained that it was impossible to correct without going back to the drawing board on the device’s design. As one Intel employee stated: “Despite our best efforts, we aren’t able to develop such a solution without completely compromising the experience.”

While not all thermal issues will result in such public recalls, manufacturers must be careful with the ways in which they choose to dissipate heat from their devices, so as to avoid complaints as well as other complications. So how can device manufacturers ensure that they’re not setting themselves up to fail when it comes to thermal management? 

It is important that design engineers address thermal factors at the very outset. Due to their close proximity to the skin, wearables are far more susceptible to complaints of overheating, with many consumers confused between natural output of heat and serious technical fault. This means that heat dissipation needs to be more ‘directed’, with the device’s internal heat flow being taken into careful consideration.

One of the best ways in which to achieve this is through the use of thermal simulation software. This allows wearables designers to refine the device’s internal layout, adjusting the position of components for improved heat flow, before a physical prototype is produced. Manufacturers can then test their product to ensure that it meets all necessary standard requirements, that components are operating below the maximum temperature limit and that the external casing is not too hot to touch.

As the technology behind thermal simulation packages has grown ever-more advanced, there has been a dramatic reduction in the time it takes to create and test detailed thermal ‘grids’. This means that developers can quickly identify potential ‘hot-spots’ inside their products and solve them prior to finalising the design.

By utilising this technology, wearables manufacturers can engineer out potential thermal complications at the embryonic stage of the design process. As a result, they can create products which better meet the complex, and often conflicting demands, of the wearables market (size, power, portability, heat).

The consumer demand for wearable devices is developing at a quickened pace, so manufacturers must look to address the issue of thermal management early on in the design process. If it is continued to be treated, by some, as a mere afterthought, then wearable devices will continue to be beset by the same issues that resulted in the Basis Peak recall.