Patent attributes
A system including a sensing device is disclosed. In one embodiment, the system has (a) an article comprising: (i) a surface having a plurality of positions and a plurality of different print elements respectively at the plurality of positions, and (ii) a plurality of substantially invisible codes respectively at the plurality of positions and associated with the plurality of positions on the surface. The system also has (b) a sensing device comprising (i) an optical sensor for reading the codes (ii) a processor coupled to the optical sensor for determining a position of the sensing device using the read code (iii) a memory unit comprising data for different audio outputs corresponding to the different print elements, the memory unit coupled to the processor, and (iv) an audio output device coupled to the processor.