Delta detection method for detecting capacitance changes

A delta detection method for detecting capacitance changes caused by relative movement between a physical object and a capacitance sensor, said method including the steps of:

• obtaining a sequence of signal readings from the capacitance sensor during said relative movement;
• establishing a plurality of time period based counting windows, each said counting window encompassing a selected portion of the sequence of signal readings differing from the selected portions of said sequence of signal readings encompassed by the other of said counting windows;
• storing the sequence of signal readings as collected raw data;
• utilizing the collected raw data, calculating the delta values between selected counting windows to provide an array of delta values;
• searching for a predetermined detection event based on said array of delta values;
• obtaining updated signal readings at periodic or otherwise programmed intervals;
• updating the stored sequence of signal readings to incorporate the updated signal readings;
• performing new calculations of delta values based on the updated stored sequence of signal readings to update the array of delta values;
• and
• searching for the predetermined detection event based on the array of delta values after updating thereof.