Apple Watch Handwashing Detection Has Been in the Works Since Long Before COVID-19

Apple Watch watchOS 7 handwashing feature Credit: Rafael Zeier
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Although watchOS 7 hasn’t (yet) delivered everything we were expecting, Apple did have one interesting surprise up its sleeve in the form of a new handwashing detection feature that will encourage users to wash their hands more frequently, properly, and thoroughly.

Considering Apple’s very proactive response to the ongoing global health pandemic, it’s easy to think that maybe this feature was something that Apple threw into watchOS 7 at the last minute, but in what now seems surprisingly prescient, it turns out the company has been working on the feature for years.

In an interview with TechCrunch, Apple VP of Technology Kevin Lynch said that this was not in any way a rush initiative undertaken by Apple, but was the result of “years of work” — including much trial and error in order to get it right.

After all, as talented as Apple’s engineers are, there’s a lot of analysis going on behind this seemingly mundane feature, and in Apple’s typical fashion, it wouldn’t include something like this unless it was sure it could do it right — and most reports from early testers have suggested that it works brilliantly well.

In fact, this feature follows Apple’s usual style of being the best at introducing a new feature, rather than merely the first one to do so. For example, Samsung released a Galaxy Watch, Hand Wash app a couple of months ago — clearly in response to the pandemic — that simply reminded users to wash their hands for at least 20 seconds, adding an extra five seconds for the soap portion of the process.

However, Samsung’s Hand Wash is really just a glorified timer app when it comes right down to it, since all it really does it time how long you wash your hands for, while also keeping track of the number of hand-washings and how long it’s been since you last washed your hands. It’s an app that’s the very definition of a slightly crazy niche app that would be the butt of jokes from users were it not for the times we now find ourselves living in.

Apple’s Handwashing

By comparison, Apple’s watchOS 7 handwashing app is an order of magnitude more sophisticated. Far beyond simply providing a countdown timer, the app actually uses the gyroscopes, accelerometers, and even the microphone to detect your hand movements and the sounds of running water in order to confirm that you’re actually washing your hands, and analyze how well you’re doing it.

It’s also built directly into watchOS 7 rather than being a separate app, and it works much more transparently. For example, users will need to opt in to enable it, but like the fitness tracking features, they won’t need to do anything to actually start it — it will simply detect when you’re washing your hands and start the 20-second countdown timer automatically.

As Lynch explains, this works on the basis of the accelerometer, which looks for the specific types of movements the occur when the wearer begins washing their hands, but of course because these can vary a lot between different people, Apple’s engineers had to go through a lot of trials and figure out all of the possible ways that people go about washing their hands.

It turns out, however, that Apple’s team discovered that those movements weren’t enough to guarantee that users were actually washing their hands as opposed to performing other similar activities, so they engaged the microphone to listen both for the sounds of running water and squishing soap to provide additional triggers.

This all gets fed into Apple’s machine learning engine to determine when handwashing is occurring and start the countdown timer along with offering up haptics and “polite encouragement” should they pause or cut their handwashing session short.

Apple is also taking this seriously enough that it’s added a new category to its HealthKit framework, allowing you to keep track of your handwashing cycles in the iOS Health app.

By all accounts the arrival of the handwashing app this year was ready to go long before the coronavirus pandemic became a thing, although it certainly seems possible that Apple may have pushed up its inclusion to line up with its other COVID-19 responses, but the key point is that this definitely isn’t a half-baked feature that Apple threw in at the last minute, but something that’s been well-researched and put together through many iterations over at least the past 2-3 years.

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