The problem with a lot of touch-sensitive controls is that the communication is one-way: They can feel you, but you can't feel them.
With touch-screen displays it's easy enough, as the button does what it says on the screen. Not all buttons are designed to be looked at as they are pushed, though. Take video-game controllers or car entertainment systems, for example, or some industrial controls. The user's attention is typically elsewhere when these are operated.
Manufacturers can mold raised blobs into the surface to show where to press, perhaps even using the shape of the blob to identify the button's function, but that means that, unlike a touch-screen, the number and function of the buttons is fixed from the moment the device leaves the factory.
At the Cebit trade show in Hanover, Germany, this week GelTouch Technologies will be showing a prototype touch-sensitive control that it thinks will get around this problem. As well as a touch-sensitive panel, it contains a network of tiny heating elements covered in a special gel that becomes rigid when warmed. By changing the temperature of the surface, GelTouch can alter its texture, so users can identify the buttons without looking. The system is compatible with multi-touch controls, and can be as thin as a few millimeters.
The temperature at which the button changes state is determined by the composition of the gel. It needs to be set high enough to avoid spontaneous state changes in warm weather or bright sunlight, say, yet low enough that the control is not hot to the touch. That makes the controls most suited to use indoors in temperature-controlled environments such as homes, factories and laboratories.
Unfortunately the gel the company is using today also becomes opaque when heated. That means that, in its current form, the control cannot be overlaid on a display, although that's something that could come later, according to GelTouch's inventor and CEO, Viktor Miruchna.
GelTouch still has a lot of work to do before this technology is ready for controlling video games or industrial machinery. The company hopes to have its first pilot project demonstrator with a partner in late 2018, far from a mass-market launch of the availability of controls "off the shelf."
As for automotive applications, it all depends on how quickly self-driving cars arrive on the market. Once they become commonplace, the cars' occupants will be able to give the audio controls their undivided attention.