Circular textual gestures for wheel controls

I have developed a prototype of a text input strategy for wheel input controls. The popularity of the ipod suggests that the wheel input paradigm is intuitive and usable. The proposed strokes are based on circular motions that follow the contour of the wheel. Spatial mnemonics based on the shape of the alphabetic characters are used to minimise the time and effort learning the uni-strokes.

The objective of the strategy proposed is to solely rely on the wheel for textual input, such that the five buttons can be used for other purposes to maintain stimulus response compatibility, or it can be used on wheel controls without buttons. Next, the technique is be easy to learn and require minimal retention as it relies on a set of spatial stroke mnemonics. Moreover, it is less dependent on visual feedback than other techniques.

The figure above shows the gestures adopted in this study for the characters of the English alphabet, space and full-stop. The circles symbolise the wheel and the arrows the path of the gesture on the wheel, where the arrowhead indicates the end position of the gesture. The gestures are based on the physical appearance of the characters. The physical shapes of the characters are therefore used as spatial mnemonics with the purpose to accelerate the learning of the circular stroke palette. For example, A is represented by a clockwise motion from east to west, symbolising the “roof” of the capital letter A. B is represented by to continuous half-circles in clockwise, followed by anticlockwise, direction to symbolise the two bumps on the capital letter B. C is represented by a anticlockwise half-circle from north to south just as the C would be written in one stroke. Most of the mnemonics are based on uppercase letters such as A, B and C, while E, F, H, R, T and U are based on lower-case letters. Others could be either upper or lower case, for instance C, K, M, N, O, U, I, J, P, S, V, W, X, Y and Z. Space is simply a gentle motion from southwest to southeast that has the appearance of the underscore character that is often used to represent space (space is a void shape).

A simulator running on a notebook computer was implemented. The notebook computer has a touchpad that can be used as an alternative the mouse. The touchpad was turned into a virtual ipod wheel by using an ipod wheel template. The template was obtained by taking a suitable piece (cut-out) from an ipod video rubber casing. This rubber casing has a thin ridge along each side of the wheel guiding the finger along a circular track. This strategy gives the user the same sensation as using the ipod wheel both in term of surface texture and physical dimensions.

The technique has not yet been tested on a panel of users under controlled conditions. You can read more about the technique in:

1. Frode Eika Sandnes, Yo-Ping Huang, "Note-Taking on the ipod,", 2007 International Conference on Multimedia and Ubiquitous Engineering (MUE'07), IEEE Computer Society Press, pp. 103-107, 2007.
2. Frode Eika Sandnes and Yo-Ping Huang, "From Smart Light Dimmers to the IPOD: Text-Input with Circular Gestures on Wheel-Controlled Devices", International Journal of Smart Home, Vol. 1, No. 2, pp. 97-108, July, 2007.