Method of assessing a user input at a virtual button of a user-input system and a user-input system

A user-input system, comprising:

• at least one force-measuring device, each force-measuring device comprising a respective signal processor and a respective plurality of piezoelectric micromechanical force-measuring elements (PMFEs), each of the PMFEs configured to output voltage signals to the respective signal processor in accordance with a time-varying strain at the respective PMFE, the respective plurality of PMFEs comprising a respective first PMFE and a respective second PMFE;
• and
• a cover layer to which the force-measuring device(s) are coupled, each of the force-measuring device(s) being coupled to the cover layer at respective positions that are laterally displaced from a center point of a respective virtual button, each respective virtual button corresponding to one or more of the force-measuring devices;
• wherein the signal processor of each force-measuring device is configured to receive the voltage signals from the respective PMFEs (PMFE voltage signals);
• wherein at least one of the signal processors is configured to obtain force-trend data from the PMFE voltage signals;
• and
• wherein a user input is assessed in accordance with the force-trend data.