Patent ID: 7148704

Claim:
A capacitive sensor for providing a detection output indicative of proximity to a sensing body extending between two electrodes of an object that is not a portion of the sensor and for providing a position output varying linearly with a position of the object along the sensing body when the object is proximate, thereto, the sensor comprising: two capacitive sensing channels, each channel connected to a respective one of the electrodes, each channel having a respective channel output representative of a respective non-linear response to a capacitive load imposed by the object when the object is proximate the body; means for operating the two channels synchronously; means for summing the respective channel outputs and for providing the detection output if that sum exceeds a selected minimum threshold; and calculation means for receiving the respective outputs from the two channels, for calculating a ratio of a selected linear combination of the outputs of the two channels, wherein the ratio varies linearly with the position of the object, and for supplying the ratio as the position output.