Human-computer interface system

A system comprising:

• a substrate comprising a set of support locations;
• a first set of electrodes arranged on the substrate and proximal the set of support locations;
• a touch sensor surface arranged over the substrate;
• a set of spring elements, each spring element in the set of spring elements:
• coupled to the substrate at a support location in the set of support locations;
• and
• configured to yield to downward displacement of the substrate responsive to forces applied to the touch sensor surface;
• and
• a second set of electrodes:
• arranged below the substrate;
• facing the first set of electrodes;
• and
• configured to cooperate with the first set of electrodes to output electrical signals representing gap heights between electrodes in the first set of electrode and electrodes in the second set of electrodes;
• wherein the set of spring elements comprises a unitary structure defining a nominal plane;
• wherein each spring element in the set of spring elements comprises a flexure:
• formed in the unitary structure;
• defining a stage;
• and
• configured to return to the nominal plane in response to absence of a touch input applied to the touch sensor surface;
• and
• further comprising a set of spacer elements, each spacer element in the set of spacer elements:
• interposed between and coupling a support location, in the set of support locations, on the substrate to a stage of a spring element, in the set of spring elements.