I build myself a scrolling led message board and every Christmas and new year I have this in my front window to greet the people in front of my house. Every year I reprogram the Arduino Uno with the wishes I want to display. I has become kind of a tradition here. I used an Arduino Uno (clone) and six MAX7219 based LED Matrix Displays forming a 192 x 8 led marquee. I chose these number of displays because it would fit my window, but the number of displays you want to use is not limited. When a line is displayed it will scroll on the display from right to left and when the display
is fully filled it will scroll on until the whole message is displayed. Then it will wait for a few seconds, clear the display with animation and start a random new message.
What components do you need?
- An Arduino Uno board; (Nano will also work)
- MAX7219 LED Matrix Display 8×32 (2 – 8);
- 5V DC Power supply at least 3A;
- Board to build it on.
I used an Arduino Uno clone but an Arduino Nano would also be possible, you would have to find the SPI and SS lines for the Nano yourself. I mounted the led displays on a wooden board with stands and the Arduino Uno at the back. In my first design I included a power supply board (the power supply of the Arduino is by far not sufficient) but in the end it was better to use a switching external power supply of 5V DC to feed the Arduino (Vin) and the Led displays. The led displays will take a lot of current, so more displays means a more powerful power supply. The connections are very easy, just two power lines and three SPI lines. The Matrix units come in 8×8 times four on a single board, with holes for the connectors at both sides. The treick is to mount the display tight together.
The software
I wrote a standalone Arduino sketch that you can modify according your own ideas, you can find the complete sourcode on my software website using the link below.
https://www.heinpragt-software.com/software_development/arduino_scrolling_text_display.html
