The user interface for text messaging via SMS has changed little since the technology was introduced on cell phones. Authoring
text with a phone keypad is tedious and error-prone. Furthermore, the cell phone intrudes into other activities while hands
hold it for authoring. In this paper we suggest a future alternative user interface for SMS messages based on a round wristwatch
device. Two button-wheels are used to access a round hi-res color display. Text input is done with a round soft keyboard that
maps intuitively to the button-wheels using the angular and radial movements of polar coordinates. Furthermore, a wristwatch
device has an aesthetics that is less intrusive than a cell phone. Since the device is always deployed, authoring is easily
interrupted to use the hands for other tasks. Informal user evaluation of a prototype implementation suggests that this novel
round design provides an improved user experience for authoring SMS compared to cell phones.
Keywords Mobile computing - round display - polar coordinate navigation - SMS - text entry - input devices - wheel interface - angular movement - radial movement