Smartwatches can be handy—perhaps too “handy,” given that they require both hands to operate. That can be a problem if your other hand is full, nonfunctioning or missing.
Researchers have tried a variety of approaches to help smartwatch users who lack a free hand, such as putting acoustic sensors on the watchband to capture inputs from finger-tapping. These efforts have concentrated mostly on enabling discrete commands, such as moving down a list of songs one at a time. Voice commands also can work for such functions, although the noise of speech isn’t always welcome.
Scientists at Dartmouth College and the University of Manitoba have been working on another approach: enabling continuous input—such as drawing letters and shapes or panning across a map—of the kind more typical of using a mouse or stylus. They hope to avoid relying on a lot of arm-tilting for these motions, since that tends to take the screen out of view.