Pushing the Limits of Physical Buttons

Technological progress is often viewed as being a force that continuously moves forward — out with the old, and in with the new. But that has not proved to be entirely true in reality. Us humans are a fickle bunch, and we tend to jump on bandwagons, then when we tire of the current trends we start to see the merits of older technologies and again “discover” them as if they were new. Consider the swing between microservices and monolithic architectures in software engineering that happens from time to time, for example. As we get fed up with the issues unique to one, we swing back to the other, forgetting the problems that caused us to abandon it in the first place.

A similar situation has been playing out with user interfaces in recent times. Touchscreens have proven to be so useful and versatile that pretty much everything — sometimes even our toaster — now has one. But people are beginning to realize that something was lost in this transition. There is now a longing for interaction with physical buttons and the clicky feedback and reliability that they offer.

Yet we do not want to go back in time to the days of computers with switch panels and other such cumbersome interfaces. We need high-tech interfaces for today’s modern applications, but more tangible than a digital interface. A team of researchers at the Korea Advanced Institute of Science and Technology have put forth a new option — a physical button called STButton. This button sports a high-resolution spatio-temporal tactile feedback display on its surface to enhance user interactions. It can provide complex force feedback and convey all sorts of information, all while providing satisfying and reliable interactions.

STButton is a standard push button, but with a dynamically reconfigurable braille-like display made of pins arranged in a five by eight grid on its surface. The pins are controlled by an Arduino Pro development board via SPI. A linear magnetic sensor was included to determine to what extent the button has been pressed, and an inertial measurement unit assists in determining the orientation of the STButton to allow for more complex interactions.

The tactile display is capable of producing both static shapes and dynamic patterns to express a variety of types of information. The team prepared several demonstrations to show how these capabilities can be used in a wide range of real-world applications. In one demonstration, the button was used to control the heater in a car seat. Pressing the button increases the heat level, which also causes a bar displayed on the tactile interface to increase in height. This allows for information to be conveyed to the driver without them having to take their eyes off the road.

Further demonstrations showed how STButton can be used to accurately select menu items in virtual reality environments or enhance user experiences in a video game. While this work is still in the early stages, and the initial prototype is a bit on the large side for most practical uses, with some refinement, the intuitive nature of STButton could make it a viable solution for the novel user interfaces of tomorrow.