In a new German study, earbuds were fitted with electrodes that can detect changes in the shape and electrical fields inside your ear canal as you make different faces. The system can detect five separate expressions so far with 90 percent accuracy: smiling, winking, turning your head to the right, opening your mouth and even making a "shh" sound.

NewScientist notes that consumer-grade versions of this tech will need to make sure, for example, you don't accidentally send out messages every time you smile. Context is key, of course -- it might only trigger a text when you're in a messaging app.

Using headphones to track changes in electrical fields isn't a brand new concept. Bragi launched a pair of buds that turn your whole face into a touchpad last November, but they only identify larger gestures, not more subtle gestures like a wink or a smile.

For those with mobility issues, having a way to manage your technology in a normalized way can be a big win. But the rest of us will benefit, too. Telling your phone to block a call or send a quick message with a wink or tap on our face feels like the next step in human-machine interaction.

Update: This article has been corrected to reflect that Bragi's headphones can recognize bigger gestures like nods and shakes.