Everyone knows that a true smile involves not only the mouth but also the eyes, but did you know that your ear canals also get in on the action, contorting along with the rest of your face? This bit of information seems trivial, but it’s what allowed computer interaction researcher Denys Matthies to create prototype earbuds that can detect the wearer’s facial expressions — and turn those into commands for your phone.

The earbuds come with special electrodes that recognize the shape of the user’s ear canal using an electrical field. This bends and flexes in a consistent fashion when people pull certain faces, allowing the earbuds to detect specific expressions. So far, they can pick up on five separate movements with 90 percent accuracy: smiling, winking, making a “shh” sound, opening your mouth, and turning your head to the side. With these hooked up to your phone, you could open texts, play and pause your music, and so on, all without using your hands.

Matthies is presenting his research at a human-computer interaction conference in Colorado this May, but spoke to the New Scientist about his work. He said the aim was not to replace current input technology, but to supplement it. If the earbuds were commercialized, they could also be very useful for people with limited mobility. “It’s currently still just a research project, but something as simple as answering a call with a facial expression could be possible soon,” Matthies told New Scientist.