Imagine you’re floating happily in a hotel pool when the iPhone you left by your beach chair rings. You know it’s an important call, and you want to answer. Maybe someday you can, by simply drawing your index finger across your palm.

That’s the idea behind some new research ^[1] at the Hasso Plattner Institute in Germany, which shows that users familiar with their smartphones can easily reproduce familiar functions with 80 percent accuracy even if they’re not actually holding a phone. Using a now-large camera that is scheduled for miniaturization, the project uses Kinect-like gesture tracking to let users interact with their phones, without taking them from their pockets.

The research is part of the larger Imaginary Interfaces ^[2] project at Hasso Plattner, which envisions humans interacting with devices without the need for keyboards or screens. (And no—unlike Gmail Gestures, announced on April 1, nothing about this is intended as a joke!)

Read more, and see a video of the invisible iPhone in action at Technology Review ^[1].