A handheld device includes a housing, a display, a MEMS magnetic field sensor disposed within the housing, wherein the MEMS magnetic field sensor is configured to sense a plurality of perturbations in magnetic fields in response to a perturbation source when the user displaces the perturbation source proximate to the handheld device, and a processor disposed within the housing and coupled to the MEMS magnetic field sensor and to the display, wherein the processor is programmed to receive the plurality of perturbations in magnetic fields, wherein the processor is programmed to determine a plurality of spatial locations in at least two-dimensions in response to the plurality of perturbations, and wherein the processor is programmed output an indication of the plurality of spatial locations on the display.