--From Forbes​

​

What do the Google Pixel 4, Vivo Nex 3, Xiaomi Mix Alpha, and a dozen other ZTE or HTC phones have in common – other than that they’re all Android phones?

They all have the ability to sense various degrees of presses in parts of the phone that do not look or feel like a clickable button. On the Pixel 4, that’d be the lower left and right side of the aluminum chassis which can be squeezed to activate Google Assistant. On the Vivo Nex 3, it’s the touch sensitive panels that replaced traditional volume and power buttons. On Xiaomi’s upcoming Mi Mix Alpha with a screen that wraps around the entire side of the phone, it’s part of the screen that can detect the varying force of a thumb press.

And the technology behind these invisible analog sensors that can be pressed depsite having no moving parts all come from Shenzhen-based tech firm New Degree Technology.

The magic happens behind the solid surface – aluminum railings, glass display panels, etc – in the form of a paper-thin, flexible sensors with tiny resistors that detects pressure from the outside surface. Once the deformation, in the form of pressure placed by a human finger or palm touch, has been registered, the resistors measure the deformation and output a voltage proportional to the amount of force that has been applied. It is effectively turning analog force into digital information for a device’s sensors and algorithm to then identify as an input.

The sensors are made in batches in a thin sheet that can fit inside a photo album book.

Ben Sin

An NDT engineer demonstrates how the sensors are applied to a phone.

Ben Sin

The founder, Hao Li, realized the potential of these so-called force sensors back in his days working as a research scientist for Motorola’s in Phoenix, Arizona.

“We worked on many areas, from semiconductors to display tech,” Li, who has a PhD in material science from the University of Maryland, says. “And it was around that time we realized the potential of a force sensitive sensor and how it could improve user interaction with their devices.”

Li says Motorola never pushed forward with the tech, but he knew that force sensitive sensors would be the future of user interactions. So in 2011 he moved back to China and started New Degree Technology, which he prefers to call NDT.

It was a long road for NDT to go from small start-up needing to prove its tech to now being used by Google in its flagship phone.

The company’s first major break came in 2015 when ZTE used NDT’s sensors underneath the screens of its Axon Mini, making it the first smartphone with touchscreen that can detect the difference between a regular and a harder press. Apple, of course, made this tech three months later when it introduced the same idea in iPhones, which the company dubbed 3D Touch.

But putting force sensitive panels underneath a screen doesn’t bring many practical benefits – there are already a myriad of ways users can initiate actions on a touchscreen, from short taps to long-presses to double taps. A more creative, and useful, use of these sensors would come a year later when HTC used NDT’s sensors on the left and right side of the U11’s chassis, allowing it to feel the sides of the device being squeezed – just like the last three Pixel devices.

A Google marketing image demonstrating the squeezing feature of the Pixel 3.

Google

A smartphone with NDT’s force sensors on the left and right side of the casing.

Ben Sin

A product render of Xiaomi’s upcoming MIx Alpha, which has a screen that wraps around one side. 

Although HTC’s U11 hit the market first, Li reveals that the company actually worked with Google on the squeezing sensors first.

And how did a relatively little-known start-up attract Google’s business? Through a failed Amazon project, ironically.

“We were at CES [Consumer Electronics Show in Las Vegas] in 2013 where our sensors won the Innovation Award,” recalls Li. “And engineers from Amazon noticed us. They were working on the Amazon Kindle Voyage at the time and thought our force sensor tech would work well on the e-reader.

“Users would be able to press on the Kindle Voyage’s screen to turn a page – the harder the press, the more pages turn at once.”

Hao Li, founder of New Degree Technology, at his company’s office in Shenzhen, China.

Ben Sin

The partnership never happened, because the key technical person working on the Kindle Voyage was let go by Amazon. According to Li, he later went to Google to work on the Pixel, where he recommended NDT to the U.S. search giant.

Today, NDT is a mid-sized Chinese tech firm with a team of about 200 in its Shenzhen headquarters and an R&D lab in Baltimore in the U.S. It controls the entire production cycle of its sensors – they have production lines manufacturing the sensors and the software algorithm are developed in-house by the company’s team of data scientists.

The company’s sensors have already been used in other products, such as kitchen ventilators and an e-cigarette (vape) pen with a pressure sensitive panel to control vapor output, but Li says the bulk of the company’s business is from smartphones right now – the company generated 137 million yuan in revenue in 2018 and will finish this year around 200 million – but he hopes to expand the company’s business to other products and industries.

There are many practical use cases for these sensors, says Li, citing examples such as elevator doors, or inside car tires to detect air pressure.

To that end, he demo’ed a pulse detection kit using just a small metal nub with NDT’s sensors inside.

A prototype of a vape pen with NDT’s force sensor instead of a traditional vaporize button.

Ben Sin

An NDT employee demonstrating a small metal nub that can detect her pulse.

Ben Sin

The Vivo Nex 3’s screen curvature is so dramatic the phone doesn’t have room for physical buttons. ... [ ]

Ben Sin

But considering how much smartphone brands are pushing their vision of a sleek, all-screen device with no buttons, ports or bumps, it would appear that there will be more demand for force sensors that can replace traditional buttons. Huawei’s recent Mate 30 Pro utilizes similar tech (although from another undisclosed vendor); and Samsung is rumored to be working on a button-less Galaxy phone for the future.

And of course, in the smartphone space, Apple is still the trendsetter. The company’s engineers considered an iPhone with no physical buttons before deciding the technology wasn’t ready. Perhaps by 2020 or 2021, the tech will mature enough to Apple’s liking. And when that happens – iPhones phase out the traditional buttons too – there will be no going back

Just look at what happened to the headphone jack.