Dynamically reconfigurable capacitive sensor array

A processing system for a keyboard input device comprising a plurality of key assemblies, each key assembly of the plurality of key assemblies comprising a keycap and a capacitive sensor, wherein each capacitive sensor disposed underneath each keycap for said each key assembly, wherein the processing system is configured to be communicatively coupled to the plurality of key assemblies, and configured to perform functionality comprising:

• selectively operating said each capacitive sensor of said each key assembly in a first mode for near field detection and a second mode for far field detection, wherein the first mode operates said each capacitive sensor of said each key assembly in a fine pitch configuration and determines a first variable capacitance, and the second mode operates said each capacitive sensor of said each key assembly in a coarse pitch configuration and determines a second variable capacitance,
• determining, for said each key assembly of the plurality of key assemblies and from the first variable capacitance, a keycap motion of the keycap of said each key assembly, and
• determining a finger presence proximate to the keycap of said each key assembly from the second variable capacitance,
• wherein the fine pitch configuration, of said each capacitive sensor of said each key assembly, comprises an inter-digitated pattern of alternating parallel transmitter and receiver electrodes, and the coarse configuration, of said each capacitive sensor of said each key assembly, comprises at least a first subset of adjacent transmitter electrodes and at least a second subset of adjacent receiver electrodes.

A method for operating a keyboard comprising a plurality of key assemblies, wherein each key assembly of the plurality of key assemblies comprising a keycap and a capacitive sensor, wherein each capacitive sensor disposed underneath each keycap for said each key assembly, the method comprising:

• selectively operating said each capacitive sensor of said each key assembly in a first mode configured for near field detection and a second mode configured for far field detection, wherein the first mode operates said each capacitive sensor of said each key assembly in a fine pitch configuration and determines a first variable capacitance, and the second mode operates said each capacitive sensor of said each key assembly in a coarse pitch configuration and determines a second variable capacitance;
• determining, for said each key assembly of the plurality of key assemblies, and from the first variable capacitance, a keycap motion of the keycap of said each key assembly;
• and
• determining a finger presence proximate to the keycap of said each key assembly from the second variable capacitance,
• wherein the fine pitch configuration, of said each capacitive sensor of said each key assembly, comprises an inter-digitated pattern of alternating parallel transmitter and receiver electrodes, and the coarse configuration, of said each capacitive sensor of said each key assembly, comprises at least a first subset of adjacent transmitter electrodes and at least a second subset of adjacent receiver electrodes.