Patent ID: 8194039

Claim:
A pointing device comprising: a housing for supporting a user's hand; a pointing sensor, mounted in said housing, for providing a pointing signal; a contour on said housing for receiving a finger of said user, said contour having curvature in two directions; and a solid-state scrolling touch sensor in said contour for detecting movement of said finger along said contour; wherein said touch sensor includes at least two electrodes, and further comprising: a circuit for detecting a contact with an electrode of the at least two electrodes, including a first, capacitive element; a second element connected to said capacitive element; a comparison circuit, having an input node connected to said capacitive and second elements, for comparing a voltage at said input node to a threshold voltage; a clamp-high circuit, connected to said node, for clamping said node high in response to a clamp-high control signal; a clamp-low circuit, connected to said input node, for clamping said node low in response to a clamp-low control signal; a controller, connected to an output of said comparison circuit, to said clamp-high circuit and to said clamp low circuit, for providing said clamp-high and clamp-low control signals and generating an output signal in response to measuring an amount of time between transitions of said output of said comparison circuit.