an apparatus and method are described herein , which simultaneously promotes a positive computing experience for users of portable computer systems and increases overall durability and longevity thereof . in one embodiment , an optical apparatus enhances the user computing experience , in one embodiment by simplifying operation , and is much more durable and long - lasting than mechanical switch and dial type devices it may replace . in one embodiment , the present invention is directed to an apparatus , which enables efficient portable computer device function , field , and data selection , gaming , input , interconnection , and other switching - related functions , simplifying operation and enhancing versatility thereof , yet without exposing the portable computer interior to any degree to incursion of environmental contamination . in one embodiment , an optical apparatus obviates openings in a portable computer package which would otherwise be required . in one embodiment , the apparatus , capable of sensing manipulation and directed by software , has a light source and corresponding light sensor .