Electrovibration: Bringing Tactile Back

Only the most committed Luddites truly mourned the demise of the feature phone. Compare Nokia’s classic 3210 with the latest iPhone and you’d have to be metabolizing a terminal dose of nostalgia to claim the former was the better device.

But there’s one aspect of those old 90s handsets that is objectively better than modern touchscreen devices: the buttons. Those chunky numbers allowed skilled fingers to write a text without looking at the screen. Try doing that on a smartphone and you’ll end up insulting your entire contact list.

OK, so the ability to send surreptitious text messages during double maths isn’t the noblest or most desirable attribute of a cellphone. Apple isn’t exactly quaking in its boots at the prospect of an eleventh-hour Nokia comeback. Still, thinking back to the days of the clandestine SMS reminds us of something we’ve lost in the age of the touchscreen: tactile feedback.

This burgeoning field — known as ‘haptics’ — has been attempting to restore tactility to the mobile experience ever since the touchscreen did away with it. The first efforts at integrating haptic feedback with smartphones offered nothing more than the rather inelegant ‘vibrate’ mode triggered by touching certain parts of the screen. It didn’t feel like the future so much as an arcade racing game from the 80s (which — scoff as we might — were early adopters of proto-haptic tech).

No sooner do we get the touchscreen of our sci-fi fever dream than we start wanting it to imitate the clunky analogue devices of the past.

Haptic technology is based on an effect known as electrovibration, a phenomenon first identified in the 1950s. Electrovibration works by fooling the fingers’ touch receptors into perceiving texture on a smooth surface. When you swipe a finger across an insulating layer on a metal surface carrying an alternating voltage, the sensation feels smoother the higher the frequency of the charge. It’s thought the sensation of friction is imitated by the varying electrostatic attraction between the metal and the deep, moist conducting layers of the skin.

It’s a cognitive sleight-of-hand, capitalizing on the human body’s propensity to calibrate new, unusual sensations to the memory of more familiar ones; with no other stimuli to go on, our brains interpret physical stimulus in ways we can recognize.

Engineers experimenting with electrotactile stimulation for commercial purposes face a major hurdle: creating an identical experience for every user. Skin conductivity not only varies from person to person, it’s also wildly inconsistent in a single individual because of a variety of internal and external factors. Even when it ‘works,’ the sensation induced by haptic technology isn’t necessarily a pleasant one.

Progress is being made in some unlikely places. Disney has their hand in electrovibration research, and Senseg has made strides toward finessing the user experience. Fittingly, Nokia has led the charge, pushing haptic feedback with varying degrees of success, and the usual suspects all have their own iterations.

It’s only a matter of time before we see haptic technology realize its full potential. Whoever makes that happen will have a hit on their hands. As Yon Visell, a tactile interface specialist from Montreal’s McGill University, said in an interview with New Scientist, “Tactile feedback is the most glaringly omitted dimension in touchscreen devices like the Apple iPhone or iPad. The device can feel what we’re touching, but we can’t.”

Apple’s ‘Taptic Engine’ — launched this year on the Apple Watch and MacBook Pro — is an indication that big tech firms may finally be investing in the future of haptic feedback.

We’re a hard-to-please bunch, us consumers. No sooner do we get the touchscreen of our sci-fi fever dream than we start wanting it to imitate the clunky analogue devices of the past. So be warned: When the first truly electrotactile mobile device arrives, the high may be short-lived — but it’ll still be a buzz.