Introduction

Synaptics ChiralMotion™ technology is an alternative to traditional wheel-limited computer mice. ChiralMotion allows long, continuous yet precise, scrolling actions. ChiralMotion is not just for scrolling; any application that could use a knob or arrows to enter one-dimensional (1-D) input is ideal for ChiralMotion.

ChiralMotion Components

A ChiralMotion-enabled mouse consists of three components: a conventional 2-D measurement subsystem (the mouse), a mode selection mechanism (a LightTouch™ capacitive button), and the Synaptics Chiral engine.

The ChiralMotion engine uses complex algorithms to achieve these simple conceptual principles:

• The initial direction of scrolling is developed from initial 2-D linear movement.
• A linear 2-D movement, extended by subsequent 2-D rotation, preserves the direction.
• Scrolling direction is correlated with 2-D rotational direction.

A graphical representation of these rules is shown below. An example of a 2-D movement path is shown in the upper half of the figure and the scrolling action is shown in the lower half. An initial upward-scrolling direction is assigned by initial upward vertical motion (A). Subsequent 2-D rotational motion (B) preserves the scrolling direction. A linear reversal (C) causes a change in scrolling direction, and a rotational reversal (D) causes a second change in direction.

Note that the amount or distance of scrolling is proportional to the magnitude of the 2-D variable. This proportionality takes maximum advantage of the inherent capabilities of the mouse. To traverse long distances, it is easier to produce a few large rotations rather than many small rotations.

Mode Selection

A Synaptics LightTouch™ capacitive button is recommended for mode selection. While the Chiral engine will produce 1-D signals from any initial motion, superior scrolling performance is achieved when making the initial direction of mouse motion the desired direction of scrolling.