Periodic sensor panel baseline adjustment

An apparatus for periodically evaluating baseline sensor output values for sensors in an event sensor panel and performing baseline drift compensation, comprising:

• a panel processor programmed for
• performing a scan of the sensor panel to obtain new sensor output values;
• normalizing each new sensor output value by subtracting a stored offset value for that sensor from the new sensor output value;
• computing a background average of sensor output values outside of those considered to be part of a patch of sensor output values presumed to be due to a touch or hover event;
• choosing an adjustment interval for the baseline drift compensation as a function of the computed background average;
• and
• performing baseline drift compensation at the chosen adjustment interval.

An apparatus for periodically evaluating baseline sensor output values for sensors in an event sensor panel every adjustment interval, comprising:

• means for performing a scan of the sensor panel to obtain new sensor output values;
• means for normalizing each new sensor output value by subtracting a stored offset value for that sensor from the new sensor output value;
• means for computing a background average of sensor output values outside of those considered to be part of a patch of sensor output values presumed to be due to a touch or hover event;
• means for choosing an adjustment interval for the baseline drift compensation as a function of the computed background average;
• and
• means for performing baseline drift compensation at the chosen adjustment interval.

A non-transitory computer-readable medium comprising program code for periodically evaluating baseline sensor output values for sensors in an event sensor panel and performing baseline drift compensation, the program code for causing performance of a method comprising:

• performing a scan of the sensor panel to obtain new sensor output values;
• normalizing each new sensor output value by subtracting a stored offset value for that sensor from the new sensor output value;
• computing a background average of sensor output values outside of those considered to be part of a patch of sensor output values presumed to be due to a touch or hover event;
• choosing an adjustment interval for the baseline drift compensation as a function of the computed background average;
• and
• performing baseline drift compensation at the chosen adjustment interval.

A mobile telephone including an apparatus for periodically evaluating baseline sensor output values for sensors in an event sensor panel every adjustment interval, the apparatus comprising:

• a panel processor programmed for
• performing a scan of the sensor panel to obtain new sensor output values;
• normalizing each new sensor output value by subtracting a stored offset value for that sensor from the new sensor output value;
• computing a background average of sensor output values outside of those considered to be part of a patch of sensor output values presumed to be due to a touch or hover event;
• choosing an adjustment interval for the baseline drift compensation as a function of the computed background average;
• and
• performing baseline drift compensation at the chosen adjustment interval.

A digital audio player including an apparatus for periodically evaluating baseline sensor output values for sensors in an event sensor panel every adjustment interval, the apparatus comprising:

• a panel processor programmed for
• performing a scan of the sensor panel to obtain new sensor output values;
• normalizing each new sensor output value by subtracting a stored offset value for that sensor from the new sensor output value;
• computing a background average of sensor output values outside of those considered to be part of a patch of sensor output values presumed to be due to a touch or hover event;
• choosing an adjustment interval for the baseline drift compensation as a function of the computed background average;
• and
• performing baseline drift compensation at the chosen adjustment interval.