i want ask you something..is it use IR more eficient ore using something else is more efficient??i have one alternative,in my computer mouse,my scroller beetwen left and right click...that scroller not using IR,it use something like potentiometer...it have 3 pin(leg)..and it can be rotate like potentiometer..when i rotate the scroller,that thing will generate some voltage pulse,i know that because i test using multimeter..do you know what it that???can u give some link about that thing??