Patent ID: 7124312
Filing Date: 2006-10-17
Classification: G06F,Y02D

Abstract:
1. A processor-readable storage medium having stored thereon instructions executable by the processor to perform steps of a method for sensing the presence of an object or body portion in contact with or close proximity to another object, the method comprising: providing a first conductor capacitively coupled to a ground to thereby form a scoop capacitor having a capacitance which varies in relation to the proximity of said object or body portion to said conductor; a pair of second and third conductors forming a bucket capacitor having a capacitance which is larger than a maximum capacitance of said scoop capacitor; and an input threshold switch; performing switching to selectively: connect at least one of said scoop capacitor and said bucket capacitor to a voltage source to charge said at least one capacitor, set a charge of said bucket capacitor at a repeatable non-zero reference level, vary the charge of said bucket capacitor from said reference level in relation to a relative size of said scoop capacitor, and apply a voltage of said bucket capacitor to said input threshold switch; detecting an input state of said input threshold switch; determining a value (TouchVal) relating to a number of cycles of said varying of the bucket capacitor charge, corresponding to a detection of a transition of said input threshold switch; and generating, based upon TouchVal, a signal indicative of an ON state wherein said object or body portion is in contact with or close proximity to said another object, and an OFF state wherein said object or body portion is not in contact with or close proximity to said object.