System and method for detecting and characterizing touch inputs at a human-computer interface

A system for detecting inputs at a computing device comprising:

• a substrate comprising:
• a top layer;
• a bottom layer;
• and
• an array of electrode pairs arranged on the bottom layer;
• an array of drive electrodes and sense electrodes arranged on the top layer of the substrate;
• a touch sensor surface arranged over the array of drive electrodes and sense electrodes;
• a set of spacers, each spacer in the set of spacers:
• arranged over an electrode pair, in the array of electrode pairs, on the bottom layer of the substrate;
• and
• comprising a force-sensitive material exhibiting variations in local bulk resistance responsive to variations in applied force;
• an array of spring elements configured to support the substrate on a chassis and to yield to displacement of the substrate downward toward the chassis responsive to forces applied to the touch sensor surface, each spring element in the array of spring elements coupled to a spacer in the set of spacers;
• and
• a controller configured to, during a scan cycle:
• read a set of capacitance values between drive electrodes and sense electrodes in the array of drive electrodes and sense electrodes;
• read a set of resistance values across electrode pairs in the array of electrode pairs;
• detect a lateral position and a longitudinal position of a touch input on the touch sensor surface based on the set of capacitance values;
• interpret a force magnitude of the touch input based on the set of resistance values;
• and
• output the lateral position, the longitudinal position, and the force magnitude of the touch input.