LED matrix scrolling display (scoreboard)
An Arduino Uno driving a chain of MAX7219 8×8 LED matrix modules with the MD_Parola library. Text scrolls across the display, and you can type a new message in the serial terminal.
Files
| File | What it is |
|---|---|
firmware/Parola_Scrolling/Parola_Scrolling.ino | Arduino sketch |
firmware/build/Parola_Scrolling.hex | Compiled firmware |
proteus/scrolling-display.pdsprj | Final design: Arduino, MAX7219 chain, red and green matrices, virtual terminal |
proteus/Arduino_Code.ino.hex | Same HEX, under the exact name the Proteus file looks for |
proteus/scrolling-display-basic.pdsprj | Earlier, smaller version |
What I fixed
The 2023 Proteus files pointed at HEX files in a temporary build folder on my old laptop (C:\Users\subed\AppData\Local\Temp\arduino_build_...). On any other PC, or after a reboot, the simulation had no program.
The final design looks for Arduino_Code.ino.hex next to the project file. That file now exists and is rebuilt by tools/build_all.sh, so the project runs as soon as you open it.
The libraries are pinned (MD_Parola v3.7.7, MD_MAX72XX v3.5.1), so the HEX can be rebuilt the same way later.
Running it in Proteus
- Open
proteus/scrolling-display.pdsprjand run it. "Welcome its me pradip" scrolls across the matrices. - Type a message in the virtual terminal (57600 baud) and press Enter. It replaces the text after the current pass.
- For the basic version, double-click the Arduino and set Program File to
../firmware/build/Parola_Scrolling.hex.
If the text looks mirrored or scrambled, the module type is wrong. Change HARDWARE_TYPE in the sketch (FC16_HW, PAROLA_HW or GENERIC_HW) and rebuild. MAX_DEVICES should equal the number of 8×8 modules in the chain.
Real hardware
- Each 8×8 module can draw up to about 300 mA at full brightness. More than four modules need their own 5 V supply, not the Uno's regulator.
- Put a 100 µF capacitor across the 5 V rail at the start of the chain, and a 10 µF one at every fourth module.
- Long chains need short, thick power wires. Thin jumper wires are the usual cause of flicker at the far end.
Rebuilding
tools/build_all.sh # rebuilds every project, including this one
