John Kestner

Prism gestural grip


A startup had developed highly sensitive and patented capacitive touch technology. They're focused on research and licensing their tech to manufacturers, but decided they needed a showcase product.

The brief was to embed their touch surface technology into a handlebar grip that could be slipped onto a motorcycle, scooter, or bicycle (with a power supply).

Interface design

With user research and interviews, I came up with a gestural language for a rider to control a connected mobile device while gripping the handlebars. I then worked with a research scientist on implementing the gestural vocabulary into an embedded library.

A screenless touch surface has some challenges in communicating its operation. Unlike a touchscreen, there's no instant feedback. We decided to add an LED ring to the hilt of the grip, that would act as a training wheel to reflect the user's actions. In addition, I developed a React Native app for setup and a guided tour to get the user familiar. It used Bluetooth to know what the user was doing, reflect that onscreen, and mark their progress through the different gestures to control their phone's functions.

Industrial design

Starting from scratch, I created several handlebar candidates for ergonomic user testing, first in foam and then 3D printed. This feedback went into a final design that I then made production-ready working together with mechanical engineers.

The design had several interesting constraints. It had to be rubbery, as a good grip should be, but it also had to support gestures on or above its surface. The electronics would be embedded in the slip-on grip, because putting them inside the metal handlebar would complicate user installation and radio communication. I placed the circuitboard under a bump that rests ergonomically under fingers bent around the grip, and the electronic engineers were able to deliver the slim shape it required.


I built a functional prototype using the company's touch surface that connected to a Windows computer over USB, a Bluetooth microcontroller board, and an LED ring. These were glued together with Python and Arduino C.

I worked with a mechanical engineer, who made 3D printed parts out of my CAD files and placed the parts within.

I developed a React Native app for setup and a guided tour to get the user familiar.

My contribution

I designed the product, including industrial and interface design. I then built a working prototype with a mechanical engineer, doing the interaction code and an accompanying app using React Native. I also did art direction and design for collateral materials—presentation deck, web site, and CES display.