At the Apple Event in September we got new iPhones, two new Apple Watches and there was this little announcement of a new gesture for Apple Watch users called Double Tap.  That’s available today and I sat down with two members of the Apple Watch team to understand more about why this matters and how you can use it.

Why on earth do we need to be able to tap our index finger and thumb together twice to activate things on the Apple Watch?  Think about when you’re carrying a heavy bag of shopping in one hand and the phone rings.  Or a message comes through.  You have to ignore it, put the bag down, or raise your wrist to your nose to answer or respond.

It doesn’t matter if you’re walking the dog or carrying shopping or coffee – there are times we just ignore what it’s telling us because it’s not convenient to interact with it.

Eric Charles, Senior Manager of Apple Watch Product Marketing explains that this all adds to how much more time we’re thinking about the next interaction “maybe you’re cooking and the timer that you set goes off, but your other hand is covered in egg yolk and there’s no way that you’re gonna put that on top of your watch. And so for a product at that point, which is normally a three to five second interaction, all of a sudden you’re thinking a lot more about how to interact and use your Apple Watch because your other hand is occupied.”

And don’t tell me you haven’t “tapped” the screen with your nose – even Eric Charles admits we do it, saying “should you try and hit the timer button, the end timer button with your nose? We have all done it. There is no shaming here, but that is what people do.”

That’s where Double Tap originates, Eric explains “providing more utility for moments like this, which are far too common, seemed like something that we should work on. How in the moment when you can’t use your other hand, what can Apple Watch do? And so that’s the problem that we decided to solve. And so we’re really excited about Double Tap. It’s a new way to interact with Apple Watch. It’s simple, it’s power efficient, it’s easy to learn, and it’s something that everyone can use to interact with the hand. With Apple Watch, with just the with hand that your watch is on, you can just simply double tap, which is fast and easy and especially convenient if your other hands are occupied.”

But it’s not just a simple software task, for Double Tap to be a default feature of Apple Watch it took new more powerful sensors and processors as David Clark, Senior Director of Apple Watch Software Engineering explains “with S9 SIP we finally had the computational capabilities on the processor as well as the power efficiencies to make this something we could enable out of the box”

It’s based on sensor data from three of our sensors in real time. We’ve got the accelerometer, we’ve got the gyroscope, and we’ve got the optical heart rate sensor.”

And it turns out, it’s the efforts Apple has gone to in monitoring our heart rates that helps enable Double Tap as David Clark says “over the years we’ve spent a tremendous amount of engineering time and effort making sure that the heart rate readings we get from Apple Watch are super accurate. The reality is, as you’re moving throughout your day, that those subtle physical movements make it so that there are little gaps in the readings that the optical heart rate sensor gets.

“But those gaps are precisely what we’re looking for here that help us detect these subtle gestures.”

Tested on hundreds of different users to fine tune the algorithm, Double Tap requires a distinct gesture by the user to ensure it’s not triggered by accident.

Many people might know that this gesture is not new to Apple Watch.  It’s been available, along with other wrist movements within the accessibility features of WatchOS.

Eric Charles explains that Assistive Touch is very different to Double Tap “assistive touch is such a unique situation in that we had a population of users who reached out vocally because they wanted to stay connected with friends and family. They wanted to track their heart rate in real time and have that data saved on their health app.”

“they just couldn’t use the watch”

And that’s why when we launched Assistive Touch and hence forth  that entire system is just built around people who, who just fundamentally can’t use, can’t use Apple Watch because of a limb difference or some other sort of motor difficulty.”

David Clark explains just how deep Apple had to dig into their WatchOS to ensure that Double Tap works every time, as you might expect it to “we had to go through the entirety of the system. Every interaction that you could possibly be encountering on watch, to figure out what’s the right thing to do here, what’s the right thing to do here? We wanted to be able to define an intuitive, meaningful thing in each of those experiences where it’s like that’s the thing the user would most obviously want to do.

A great example of that is how Messages work  as Eric Charles explains “you can scroll through a message, but that reply button through Double Tap goes automatically to dictation because we’re assuming that if you’re in that mode, you just don’t need a keyboard”

It just works.

Having tested Double Tap for the last few weeks, I find myself using the Apple Watch far more – a worthy update.

Double Tap works on Apple Watch Series 9 and Ultra 2 with the latest WatchOS 10.1 which is now available.