arduino mega controller

I used a mega which has 69 possible pins, which makes the job much easier but more expensive. With enough pins, just take each pin to an opto coupler. You can also use a Nano which has 16 pins but then you'll need to get tricky using a shift register to send signals serially from each pin or will need to build an LED type matrix. both of these are more technically challenging.
Enjoy!
Chris