Was anyone able to find a solution to marco131's question? I have the same issue. Ball ps2 mouse works great, but optical ps2 mouse lights up but no data. It seems to stick on the statement checking for when the clock goes low [while (digitalRead(MCLK) == HIGH)]. Any help is hugely appreciated.
FYI: I am making a stitch regulator for my wife's sewing machine which will increase speed that faster the fabric is moved and slower stitching the slower the fabric moves to achieve constant distance between stitches. All working, but optical would be better than ball mouse on fabric. Thanks!