How big are the digits? For really big, like 3 or 6 LEDs/segment powered from 12V, then use strips if WS2812B can used with all digits as one big long string, or perhaps one string per digit, to allow multiple colors. If single color, than a shift register per digit can be used, with the data and clock shared among all digits.
(Youtube, look for cardinalflyer2011, I can't keep the smart-pasting here from screwing up the link)
I offer a basically ProMini-based board (off board FTDI used to load code) with up to 12 shift registers for driving up to 12 digits.
Here it is on accelerated count-up mode testing alarm clock function:
(Youtube, look for cardinalflyer2011, I can't keep the smart-pasting here from screwing up the link)
and here as a scoreboard with an RF receiver connected with a simple 4-button remote sending score up/down commands on two buttons, third used to increase period/quarter/inning (hockey periods in this case it looks like).
(Youtube, look for cardinalflyer2011, I can't keep the smart-pasting here from screwing up the link)
This is the board itself
http://www.crossroadsfencing.com/BobuinoRev17/
