A sensing device for sensing coded data on a surface, generating indicating data using the coded data, and transmitting the indicating data to a computer system is provided. The coded data is indicative of an identity of a region of the surface and of a plurality of locations of the region, whilst the indicating data comprises data regarding a region identity of the surface and data regarding a position and/or movement of the sensing device relative to the surface. The sensing device comprises: (a) an image sensor configured for sensing and capturing images of at least some of the coded data when the sensing device is placed in an operative position relative to the surface; (b) a processor for generating the indicating data using the captured images; and (b) a transmitter for transmitting the indicating data to the computer system. The processor is configured to (i) identify at least some of the coded data from one or more of the captured images, (ii) determine an orientation, within the captured images, of the at least some of the coded data, (iii) decode the at least some of the coded data; and (iv) generate the indicating data using the decoded coded data.