Researchers at the Human-Computer Interaction Institute at Carnegie Mellon University have developed an iterative zooming technique that lets users input text into smartwatches or ultra-small computers. Users can enter about 10 words per minute at high accuracy on a keyboard the size of a penny, say the researchers.

Called ZoomBoard, the text entry technique is based on the familiar QWERTY keyboard layout. The full keyboard is really small on a watch-size display, but by tapping the screen users can enlarge individual keys.

Further development of ZoomBoard might include a language model, a standard feature on most soft keyboards that suggests possible words based on the first few letters typed; for ZoomBoard, this might also involve adjusting the centering point of the first zoom step over a predicted letter.

The researchers say ZoomBoard also could be useful on larger keyboards for people who have movement disorders that make typing difficult, or for people who are using their keyboards while jogging.