Have you worked with ready-made 8x8 LED matrix as displays? They come in various sizes and are quite interesting to work with. A large readily available size is around 60mm x 60mm. However, if you are looking for a much larger ready-made LED matrix, you may be out of luck.
For this project, we will be building a single color large LED matrix display which is made up of a few large 8x8 LED matrix modules daisy-chained together. Each of these 8x8 LED matrix modules is around 144mm x 144mm in size.
The unique thing about this display is that other than the LEDs, one is able to view the background behind the display. This offers some creative use of these displays such as placing them against glass panels whereby people around it is able to see happenings behind the display. You may place some form of backing for your display if you find it distracting to read what is being displayed.
For this project, we will be using 10mm orange color LEDs to build the display. You may use LED sizes of your choice for your display. Commonly available sizes are 3mm, 5mm, 8mm, and 10mm.
Though our display is not designed to work with any particular microcontroller, we will be using the popular Arduino board in this instructables to drive it via SPI using only 3 signal wires. For those who prefer not to mess with too much wiring, the large 8x8 LED matrix module is available as a DIY kit at our Tindie Store.
To build this project, basic electronics knowledge with electronics component soldering skill and some knowledge on using the Arduino are required.
You may view the following YouTube video to see what we will be building.
There are many Arduino libraries out there which can support to drive our LED Matrix display. However, we will be using the awesome Parola for Arduino library contributed by Marco Colli for this project. Our demo example is adapted largely based on one of the Parola library's example but our demo will not be showcasing the full capability of the library. It will simply display one of five predefined messages scrolling across the display which is selected by a push button.
Our last instructable is JolliCube - an 8x8x8 LED Cube. Marco Colli is sharp to notice in the instructable that the LED Cube PCB design is modular and that there could be a possibility to separate the 4 modular parts on one board and set them up narrow end to narrow end, effectively creating a very large 8x8 flat matrix (vertical) that can be used with the Parola library he created. He is spot-on and here we present you the large 8x8 LED matrix display in which the base PCB is a part of our JolliCube base PCB.
For our design, we will solder the LEDs together using just the long legs on commonly available LEDs. Here, we will be using clear 10mm orange LEDs with long legs. You may use any size and color of LED available but the LED leg length (more than 23mm) should be sufficiently long for them to be bent and soldered together. The LEDs will be arranged as an 8x8 matrix with the cathodes soldered together for the rows and anodes soldered together for the columns.