or....the dark majikal mysteries of it.... :-) "Alan B. Pearce" wrote: >So far with my testing, I'm right on and no longer have these false >transistions. So you have just created an 'optical Schmitt trigger' ... Welcome to the joys of analogue interfacing. ;) -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist --------------------------------- Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist