I intend to build a 14 x 14 standard 3mm blue LED matrix, for a WordClock-like project, but I have no idea how to control it. I've heard of multiplexing with NPN transistors, but I'm concerned about the resistors values. And still, 28 ports it's still too much for my Arduino Nano.
What can I do to control the LEDs? Is the multiplexing idea right, or am I completely on the wrong path?