US Patent 7589709 Method of measuring the movement of an input device

A small and cheap user's input device for measuring scroll-and-click movements of a finger (132) or other object relative to the device comprises at least one sensor unit (124, 126, 130) and sensor signal analyzing means (136) to derive click information and scroll information from the same sensor signal. The analyzing means is designed such as to recognize a first typical time pattern of a click action and a second typical time pattern of a scroll action. Moreover in analyzing a sensor signal obtained during a time interval data obtained during other time intervals can be used to supply reliable signals. This device can be used in a number of different consumer apparatus, such as a mobile phone (134).