Data input on small devices can be difficult because of the limited size of the interface. Built-in sensors bring alternatives for user input on small devices. We propose to use device tilt positions to represent data input. The built-in accelerometers are used to derive the tilt positions. The combinations of tilt positions are mapped to characters and commands. Users conduct data input by tilting the device to dedicated positions consecutively and clicking a button to confirm an operation. Feedback is audible so that the display is not required. Hence this tilt-click positioning input mechanism is onehanded and eyes-free. In this paper, we present two positioning input systems using five positions and nine positions respectively. Two experiments are conducted showing that novice users achieved 2.8 WPM (words per minute) with audible feedback in text input, and 33.4 SPC (seconds per calculation) with audible feedback for five digit calculations.
Available at: http://works.bepress.com/chunming-gao/1/