Classifying input objects interacting with a capacitive button

A processing system for an input device comprising a first plurality of sensor electrodes overlapping a display and a second plurality of sensor electrodes, the processing system comprising:

• a sensor module configured to operate the first plurality of sensor electrodes to detect positional information for an input object in a first sensing region overlapping the display and to operate the second plurality of sensor electrodes to detect a presence of an input object in a second sensing region overlapping the second plurality of sensor electrodes, the sensor module configured to:
• drive a capacitive sensing signal onto at least one of the second plurality of sensor electrodes, and
• receive a first resulting signal and a second resulting signal on one or more sensor electrodes of the second plurality of sensor electrodes;
• and
• a determination module configured to determine whether the input object is contacting the second sensing region based on a ratio between the first and second resulting signals.

An electronic system comprising:

• a display;
• a first plurality of sensor electrodes overlapping the display;
• a second plurality of sensor electrodes;
• a processing system communicatively coupled to the first and second plurality of sensor electrodes, the processing system configured to:
• operate the first plurality of sensor electrodes to detect positional information for an input object in a first sensing region overlapping the display;
• and
• operate the second plurality of sensor electrodes to detect a presence of the input object in a second sensing region by:
• driving a capacitive sensing signal to detect the input object onto first and second electrodes of the second plurality of sensor electrodes,
• receiving a first resulting signal from the first electrode and a second resulting signal from the second electrode, and
• determining, based on a ratio between the first and second resulting signals, whether the input object is at least one of contacting the second sensing region and hovering over the second sensing region.