While smartwatches may indeed be designed for ease of use, utilizing their touchscreen controls does require the user to have the hand of their opposite arm free. What happens if that hand is otherwise occupied? Well, voice control is one option, but researchers from Dartmouth University are developing another. Their WristWhirl prototype can be controlled by making joystick motions with the hand of the arm that's wearing it.

Users start by making a pinching motion with the fingers of that hand. A piezo vibration sensor in the watch strap detects that movement and powers up 12 infrared proximity sensors, which are also built into the strap.

Commands are then made by moving the hand as if it were operating a joystick. The proximity sensors monitor those movements, with an onboard Arduino Due microcomputer recognizing gestures that are assigned to specific commands. Another finger-pinch turns the sensors back off again, when the session is over.

Test subjects have successfully used the prototype to perform actions such as accessing app shortcuts by drawing shapes, scrolling through songs on a music player app by swiping their hand left or right, panning and zooming on a map by swiping or rotating the wrist, and playing video games by tilting the wrist.

The technology is going to be presented at the ACM Symposium on User Interface Software and Technology on October 19. On the off chance that you're not going to be there, you can see a demo of it in the video below.