1. A method of operating a capacitive sensor assembly comprising at least one capacitive sensor element and a capacitance-to-digital converter (CDC) that supplies output codes corresponding to sensor element capacitance, comprising acts of: a. determining an ambient value of the CDC output codes; b. modifying at least one threshold value in response to changes in said ambient value; and c. detecting proximity of a ground mass to the sensor element and preventing the modification of threshold values while said proximity is detected.