Question

I am trying to build a matrix array of LEDs. But I have only 8 pins to give data and 100 LEDs to display for a single character. How can I accomplish this?

Answer 1

I'm a bit new to this (so take this with a grain of salt), but I can think of a couple ways. Commercially, this is an example of a board which can control up to 16 LEDs, but there are others which control more: http://jeelabs.com/products/dimmer-plug.

However, you could make a logic chip which takes 8 inputs and outputs up to 256 (2^8) different outputs if you assign each input as a 0 or a 1 (on or off). But then you'd have to have a separate power supply to power the LEDs, as now your 8 pins themselves would just represent data (0s and 1s) and not necessarily power.