A portable electronic device comprising: an external surface of a user interface; a plurality of piezoelectric transducers (1209, 1401) coupled to the external surface, the piezoelectric transducers generating electrical outputs originating at the piezoelectric transducers in response to mechanical actuation applied at the external surface; and a controller configured to perform an electronic function of the portable electronic device in response to the plurality of piezoelectric transducers generating the electrical outputs, characterized by: a first differential component coupled to two of the plurality of piezoelectric transducers, the first differential component generating a first differential output based on a first difference between the electrical outputs generated by said two of the plurality of piezoelectric transducers; a second differential component coupled to said two of the plurality of piezoelectric transducers, the second differential component generating a second differential output based on a second difference between the electrical outputs generated by said two of the plurality of piezoelectric transducers; and the controller being further configured to determine a direction of navigation, associated with a directional press on the external surface, in response to the first and second differential components generating the first and second differential outputs, respectively. an external surface of a user interface; a plurality of piezoelectric transducers (1209, 1401) coupled to the external surface, the piezoelectric transducers generating electrical outputs originating at the piezoelectric transducers in response to mechanical actuation applied at the external surface; and a controller configured to perform an electronic function of the portable electronic device in response to the plurality of piezoelectric transducers generating the electrical outputs, characterized by: a first differential component coupled to two of the plurality of piezoelectric transducers, the first differential component generating a first differential output based on a first difference between the electrical outputs generated by said two of the plurality of piezoelectric transducers; a second differential component coupled to said two of the plurality of piezoelectric transducers, the second differential component generating a second differential output based on a second difference between the electrical outputs generated by said two of the plurality of piezoelectric transducers; and the controller being further configured to determine a direction of navigation, associated with a directional press on the external surface, in response to the first and second differential components generating the first and second differential outputs, respectively. a first differential component coupled to two of the plurality of piezoelectric transducers, the first differential component generating a first differential output based on a first difference between the electrical outputs generated by said two of the plurality of piezoelectric transducers; a second differential component coupled to said two of the plurality of piezoelectric transducers, the second differential component generating a second differential output based on a second difference between the electrical outputs generated by said two of the plurality of piezoelectric transducers; and the controller being further configured to determine a direction of navigation, associated with a directional press on the external surface, in response to the first and second differential components generating the first and second differential outputs, respectively.