What do you do with 144 7-segment ... with a single Arduino Nano. Even charlieplexing won’t get you that many I/O lines. The solution was a nifty little chip called the MAX7219.

A while back, [limpfish] bought a few four-digit ... the MAX7219 driver chip. With chips in hand, [limpfish] designed a small breakout board for the MAX7219 and two common anode 4×7 segment ...