Relative-position, absolute-orientation sketch pad and optical stylus for a personal computer

A computer sketch pad and stylus for use with an existing notebook computer, comprising:

• (1) at least one sketch pad, each said sketch pad having a top surface and a bottom surface;
• (2) stylus-cooperating indicia on the top surface of said at least one sketch pad;
• (3) attachement means for attaching said stylus-cooperating indicia to said existing notebook computer such that said stylus-cooperating indicia is visible at least when said existing notebook computer is in use;
• (4) an optical stylus comprising at least one camera oriented for optically detecting said stylus-cooperating indicia, and said optical stylus additionally comprising transmitting means for transmitting data derived from its optical detections to said existing notebook computer,
• wherein:
• a. said optical stylus additionally comprises processor means for interpreting successive camera images to derive movement data;
• b. said optical stylus additionally comprises at least one contact detector on at least one end of said stylus that corresponds to the oriented view of at least one camera;
• c. said transmitting means transmits to said existing notebook computer the derived movement data and at least the contact and no contact status of said contact detector;
• d. said attachment means comprises an adhesive on said bottom surface of said sketch pad;
• e. said stylus-cooperating indicia includes indicia for distinguishing horizontal motion from vertical motion and also establishes at least one fixed angle;
• f. whereby said fixed angle disambiguates motion up from motion down and motion left from motion right, regardless of the orientation of the stylus to the sketch pad and regardless of any rotation about the stylus's own longitudinal axis.

A method of upgrading an existing computer with a stylus-type of input device, comprising the steps of:

• (1) applying stylus-cooperating indicia to a surface of said existing computer, said stylus-cooperating indicia including at least a sketch pad, positioned so that said sketch pad is accessible to a stylus when said computer is in use;
• (2) providing an optical stylus comprising at least one camera oriented for optically detecting said stylus-cooperating indicia;
• (3) establishing a communication channel for transmitting data derived from said stylus's optical detections to said existing computer;
• wherein said stylus-type input device provides relative-position, absolute-orientation movement data to said existing computer and
• further wherein said existing computer is an existing notebook computer having a flat surface in front of its keyboard, and said stylus-cooperating indicia is applied to at least part of said flat surface, and said step of applying stylus-cooperating indicia is selected from the group consisting of:
• a. peeling a protective cover off of an sketch pad adhesive sticker and affixing said sketch pad adhesive sticker to said flat surface;
• b. applying a sketch pad transfer decal that transfers pigment to said flat surface;
• c. affixing a sketch pad member to said flat surface by applying a separate adhesive;
• d. affixing a sketch pad member with a fastener;
• e. affixing a sketch pad member magnetically;
• f. direct printing onto said flat surface;
• and
• g. chemical etching a sketch pad onto said flat surface.