Optical user input device

Abstract

The invention provides an input apparatus, a games controller for a games console and an analogue control stick. The analogue control stick comprises a shaft pivotally mounted for movement about at least two orthogonal axes and a target surface disposed at a proximal end of the shaft. The analogue control stick comprises at least one light source and a sensor, for capturing images of the target surface illuminated by the light source at a polling interval. A processing unit compares a current image of the target surface with the immediately preceding image of the target surface captured by the sensor to determine magnitude and direction of any incremental movement of the target surface relative to the sensor between capturing the compared images. The processing unit accumulates data, in a memory cache, indicative of the incremental movements to calculate an absolute position of the target surface relative to a predefined or origin position. The analogue control stick comprises an origin position detection system for determining return of the target surface to a predefined origin position. The processing unit is configured to clear the cache of accumulated incremental movement data upon detection of the target surface being disposed at the predefined origin position.