“With this technology, you can feel three-dimensional shapes in mid-air without actually touching anything,” say Singhal and Phutane. “When you press an elevator button, you will feel mid-air touch sensations to provide feedback that you pressed it.”
Singhal and Phutane built this concept with accessibility in mind: “it features touchless tactile braille (as well as audio feedback) for the visually impaired, intuitive gestures for opening/closing doors, and a lively button magnification on hover for improved accuracy”.
Read more about their Touchless Elevator Concept on Medium where they explain how they see this idea as a starting point for many more intuitive and accessible contactless interactions. The source code for this concept is available on Github.