The following project description is an entry in the Visual Representation of Learn Experience Innovate of the Academic Palloza, Fall 2010 competition held at the University of Advancing Technology.
The overall process in design is actually fairly simple. The circuit design shown in Figure 1 below shows the simple circuit used for each LED to be lit.
Figure 1. Schematic.
Figure 1 is easy to understand. Signal goes from a Digital I/O pin, through an LED, a 150 ohm resistor, and to ground. It can be repeated for as many pins as the user wants. The software is set up to run a 5 X 9 grid of LEDs. The software uses a 5 X 15 array that represents all of the LEDs plus the extra on the right, and the text scrolls to the left.
Below are several photos from the testing phases of the design and implementation of software. Below that is the source code, written for an Arduino Mega.
Early testing phase of the design and wiring.
Testing of everything wired.
The video above shows an early version, before the resistors were added to the LEDs (A VERY BAD CHOICE TO DO) and before the serial communication was working.
The source code can be found here.
Expect to work about 5 hours to get all of the wiring working, and the source code implemented and debugged for your setup.