well, the reason that I start with 8051s is I know a bit about 8051s and nothing else.

advise from friends are, let's make the circuit work first and make sure the idea work. So I did it.

Yes, I think I need a MCU instead of some discrete component. Since the change of patter is a bit complex and I would like to change the pattern with little effort.

regarding to the 4bit processor, it sounds good to me but I know nothing about it. Mind to explain more?

Thanks