Sensing device
A sensing device is disclosed. The sensing device interacts with a surface having coded data thereon. The coded data is made up from tags. Each tag encodes a unique identity of the surface, and the location of that tag on the surface. The sensing device has an optical sensor for capturing images of the coded data on the surface when the sensing device is placed in an operative position relative to the surface. The sensing device also has a processor for processing the captured images to determine the unique identity of the surface and the operative position of the sensing device on the surface. A movement sensor for generating movement data is also included in the sensing device. A transmitter of the sensing device transmits indicating data to a computer system. The indicating data includes data regarding the identity of the surface, data regarding the operative position of the sensing device and said movement data.
1. A sensing device comprising:
an optical sensor for capturing images of coded data on a surface when the sensing device is placed in an operative position relative to the surface, the coded data comprising a plurality of tags, each tag encoding a unique identity of the surface, and a location of the respective tag on the surface;
a processor for processing the captured images to determine the unique identity of the surface and the operative position of the sensing device on the surface;
a movement sensor for generating movement data; and
a transmitter for transmitting indicating data to a computer system, the indicating data comprising data regarding the identity of the surface, data regarding the operative position of the sensing device and said movement data.
2. A sensing device according to claims 1 , further including a marking nib for marking the surface.
3. A sensing device according to claim 1 , wherein each tag has four possible orientations relative to the surface and wherein each tag orientation contains one codeword placed at that orientation.
4. A sensing device according to claim 1 , wherein the coded data includes periodic elements, the processor processing the periodic elements to generate further movement data.
5. A sensing device according to claim 1 , wherein the processor further determines an orientation of the sensing device relative to at least some of the coded data.
6. A sensing device according to claim 1 , wherein the movement sensor comprises a pair of orthogonal accelerometers.
7. A sensing device according to claim 1 , further comprising a force sensor configured to sense a force applied to the surface by the sensing device.