How to protect sensors from the elements, even your sweat

Runner wearing smart phone and watch in snowy conditions
(Lifemoment / iStock / Getty Images Plus) Snow and rain aren't the only threat. Sweat on your wearables can wreak havoc on the electronics inside. Coatings a fraction of the thickness of a human hair can protect them.

You probably don't consider your own body a hazard to electronics, but the fact is that your own sweat can wreak havoc on the sensitive electronics in earbuds, headphones, and other wearables. And since many of us wear these devices while exercising and in steamy weather, the threat is real.

Conformal coatings can protect against water, corrosion and other hazardous environments—even the salty liquid that is sweat. FierceElectronics spoke to Zsolt Pulai, VP of Technology & Engineering at HZO, a maker of nanocoatings, about the rise in the use of protective coatings for wearables, edge devices, and electronics in general.

FE: What are conformal coatings and what have been some of the recent innovations in the technology?

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Pulai: Conformal coatings are specialty materials, applied onto a PCBA or other components for protection against water, corrosion, and hazardous environments. They get their name for ‘conforming’ or enveloping whatever they are applied to. Traditional conformal materials include silicone or acrylic coatings, but the next-generation of conformal applications involves protective thin-film coatings that are a fraction of the thickness of a human hair, but offer superior protection compared to current conformal coatings. Thin-films and nanocoatings is where HZO is currently focused.  

FE: With all the other things for engineers to worry about, is protection from the environment sometimes an oversight?

Pulai: A few short years ago, “only” a few billion electronic devices were out there, but we’re rapidly approaching numbers of over 40 billion connected devices with no end in sight. We rely on these electronics more and more; they are part of our everyday lives. Because of this, we need to protect them from the corrosive environments they are operating in. It’s indeed an oversight, but it’s getting better as companies are recognizing the need. Unfortunately, today mostly it’s an aftermarket thought to protect these devices, instead of designing it into the device from day one. This is where HZO can help, that from day one, the device protection is part of the product, ready to protect. 

FE: Can you share an example or two of some of the worst environments that you’ve been called in to protect against?

Pulai: With consumer electronics, it would be sweat on an ear bud or pair of headphones. This salty liquid wreaks havoc on sensitive electronics! Or the same sweat on a glucose monitor. In industrial such as remote sensors of oil rigs and more, we’re fighting against humidity, salt fog, corrosive liquids a more. It’s a real battle! Thankfully we’ve been able to meet the challenges of our customers which helps everyone involved, especially the user.

FE: Are there any common misunderstandings about conformal coatings and environmental protection?

Pulai: Traditional conformal coatings provide some level of protection. But they don’t protect against a variety of environments. They might be good against some liquids, like water, but in the environment, there are much more “dangers” out there, fog, humidity, chemicals, oils – just to name a few. Depending on the protection required by our customers, we provide a solution to address these “dangers”. 

FE: How are the coatings applied?

Pulai: HZO applies our coatings utilizing a general process called Chemical Vapor Deposition, or CVD. Essentially our coating material is released in a gas form under vacuum in a coating chamber. This process provides incredible coverage, truly conforming to every section of a PCBA. Our large propriety coating chambers allow for mass application of our protective coatings. 

FE: What about thermal dissipation? Do these coatings create another layer that could create a built-up of heat that would be detrimental for electronics?

Pulai: The thin-film and nanocoatings we apply onto a PCBA are so thin, they are barely noticeable, but still more than adequate to protect the device. You can’t touch it, you can’t feel it, you don’t see it, but it’s there and it does its job: to protect the device from the elements. Since they are so thin, there is little to no impact on the performance of the board. This means the coatings don’t create trapped heat. Sometimes it’s even the opposite where the larger surface area could help with heat dissipation.  Our customers love this about our solutions. 

FE: Electronics are winding up in more places that I am sure engineers never anticipated, including toilets! (Although that last one--probably not intentionally!) How should product developers be considering the environment their product will be used in and what level of protection they’ll need?

Pulai: Every day, electronics become more a part of our lives, to the point where we sometimes don’t even realize we are surrounded by them. Take for example, our vehicles – 15-20 years ago the “only” electronics was a tape player or light switches. Today, these are replaced and augmented with GPS, screens, lane assist, communication protocols, tracking capabilities, electronic locks, diagnostics, remote controls, engine monitors, and a whole host of sensors. Consumer electronics are no exception: an average person carries 4.7 electronic devices on their person each day into every environment they find themselves in. These devices need to be protected. Protected against everything we know could harm them, but also against things we don’t even think of. 

Editor's Note: Zsolt Pulai of HZO will be speaking on strategies for embedded developers for protecting electronics at our first online Embedded Innovation Week, a digital event series taking place Sept 28-Oct 1 with a focus on IoT, AI, security and more. For more information and to register for your free pass, click here


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