YourITronics

This project is for beginners, but even people with experience can find it interesting the solution for doubling the columns of the display. They say that a picture worth a hundred words, then what would worth a movie? I recall when i was learning micro controller programming, after i made the led blink, and a few led animations the next step was to build a display suited for text or animation, at this moment everybody tries to power each led individually but since you can’t use a 150 pin micro controller you look for more clever solutions, which is the row-column addressing.

On the video the author explains step by step how to control 120 LED’s with just 16 pins, with normal row-column addressing you can control only 64 LED’s, by using a simple trick you can double your resolution. Although they omitted the fact that you need to use some buffer circuit, or limit the total current of your LED’s in a row, be aware that a micro controller pin can handle only 20mA.

If you will be interested, I can post a more advanced method which uses only 7 pins and can control a display with a few thousand LED’s.

Simple LED display board: [via] – [Link]