User command determination based on a vibration pattern

A method, comprising:

• providing at least one surface on a body of an eyewear apparatus, wherein the at least one surface is to receive one or more user inputs to convey a command to the apparatus, wherein providing the at least one surface includes forming a surface pattern, wherein the user input includes one or more finger drags along the surface pattern, wherein the surface pattern includes an array of surface elements, wherein forming the surface pattern includes disposing the surface elements on the surface at increasing distances between each other, wherein a distance between a first surface element and a second surface element that is adjacent to the first surface element is smaller than a distance between the second surface element and a third surface element that is adjacent to the second surface element;
• disposing at least one sensor, comprising a piezoelectric transducer responsive to vibration, to be in contact with the body of the apparatus, to detect vibration manifested by the surface in response to the one or more user inputs, and generate a signal indicative of vibration;
• disposing a controller on or inside the body of the apparatus;
• and
• electrically coupling the at least one sensor with the controller, to process the signal indicative of vibration, to identify a pattern of vibration, and determine the command that corresponds to the vibration pattern, wherein the command is to interact, operate or control the apparatus.