There are countless 8x8 LED matrix displays on the Internet, but the vast majority of them are quite small. Of course, there are a few that are somewhat large, but most of them fall into the “novelty” category.

What we wanted to create was a Shield for the Arduino that would, when used with a user supplied power supply of 5 to 35vdc, be capable of powering very large 8x8 matrix displays composed of commonly available LEDs. For example, the 8x8 matrix displays we use for final testing purposes are 12” x 13” and have 576 LEDs. The main problem with this is that a typical LED uses around 2.0 to 3.0 ma for operation so, even with multiplexing, powering a large number of LEDs wired in parallel calls for a heavy duty power supply.

The obvious solution to this problem is to wire the LEDs in series, keeping the current low, while increasing the voltage to keep the voltage drop across the series wired LEDs at the correct value, and that’s what our LED Driver Shield is for.

In order for the Shield to work, you will need to provide a common cathode 8x8 LED matrix with the number of LEDs required to make a matrix of the size that fits your needs. For example, one of our 8x8 matrix displays has 576 LEDs, some 5mm type and some 10mm type, and draws only around 60ma with 30vdc applied.

So, where did the 30vdc come from? For testing purposes we use a simple adjustable voltage converter that takes 12vdc from one of our bench supplies and converts it to any voltage from 15 to 35vdc. These converters are very inexpensive and some are available here on Tindie.

So, in addition to our LED Driver Shield, you will need to supply a common cathode 8x8 LED matrix and a variable voltage source of approximately 15 to 35vdc at around 500ma. Each LED Driver Shield can control one matrix, so if you wanted to make, say, a large stereo audio spectrum display you would need two of our LED Drivers and, of course, two matrix displays.

Why not click on our Documentation link and get the complete specs, along with the schematic and picture examples of what can be done with our LED Driver Shield?