Touch detection techniques for capacitive touch sense systems
First Claim
1. A machine-readable storage medium that provides instructions that, if executed by a machine, will cause the machine to perform operations comprising:
- measuring a capacitance value of a capacitance sensor within a capacitance sense interface to generate a measured capacitance value;
analyzing the measured capacitance value to determine a baseline capacitance value for the capacitance sensor;
updating the baseline capacitance value in real-time based at least in part upon a weighted moving average of the measured capacitance value;
analyzing the measured capacitance value to determine whether the measured capacitance value drops below the baseline capacitance value by a negative threshold value for a predetermined period of time, wherein the predetermined period of time is greater than a single clock cycle; and
updating the baseline capacitance value based on the measured capacitance value measured after the measured capacitance value dropped below the negative threshold value.
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Accused Products
Abstract
A technique for recognizing and rejecting false activation events related to a capacitance sense interface includes measuring a capacitance value of a capacitance sensor within the capacitance sense interface to generate a measured capacitance value. The measured capacitance value is analyzed to determine a baseline capacitance value for the capacitance sensor. The baseline capacitance value may be updated based at least in part upon a weighted moving average of the measured capacitance value. The measured capacitance value may also be analyzed to determine whether the capacitance sensor was activated during a startup phase and to adjust the baseline capacitance value in response to determining that the capacitance sensor was activated during the startup phase.
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Citations
18 Claims
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1. A machine-readable storage medium that provides instructions that, if executed by a machine, will cause the machine to perform operations comprising:
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measuring a capacitance value of a capacitance sensor within a capacitance sense interface to generate a measured capacitance value; analyzing the measured capacitance value to determine a baseline capacitance value for the capacitance sensor; updating the baseline capacitance value in real-time based at least in part upon a weighted moving average of the measured capacitance value; analyzing the measured capacitance value to determine whether the measured capacitance value drops below the baseline capacitance value by a negative threshold value for a predetermined period of time, wherein the predetermined period of time is greater than a single clock cycle; and updating the baseline capacitance value based on the measured capacitance value measured after the measured capacitance value dropped below the negative threshold value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus, comprising:
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a capacitance sense interface including a capacitance sensor having a baseline capacitance value associated with the capacitance sensor; a capacitance measurement circuit coupled to the capacitance sense interface to sense a measured capacitance value of the capacitance sensor and output a signal indicative of the measured capacitance value; and startup logic coupled to analyze the signal to determine whether the capacitance sensor was activated during a startup phase and to adjust the baseline capacitance value in response to determining that the capacitance sensor was activated during the startup phase, wherein the startup logic determines whether the measured capacitance value crosses a negative threshold value for a predetermined period of time, wherein the predetermined period of time is greater than a single clock cycle. - View Dependent Claims (10, 11, 12, 13)
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14. A method, comprising:
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measuring a capacitance value of a capacitance sensor within a capacitance sense interface to generate a measured capacitance value; analyzing the measured capacitance value to determine a baseline capacitance value for the capacitance sensor; updating the baseline capacitance value based at least in part upon a weighted moving average of the measured capacitance value; analyzing the measured capacitance value to determine whether the measured capacitance value drops below the baseline capacitance value by a negative threshold value for a predetermined period of time, wherein the predetermined period of time is greater than a single clock cycle; and updating the baseline capacitance value based on the measured capacitance value measured after the measured capacitance value dropped below the negative threshold value. - View Dependent Claims (15, 16, 17, 18)
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Specification