TL;DR
Clem Mayer revamped an old LED matrix display using an Arduino UNO R4 WiFi, breathing new life into the quirky device while addressing safety concerns. Initially, the display worked fine and even showcased its last programmed message, but upon inspection, Mayer discovered a risky setup: the AC-to-DC adapter had exposed wires soldered directly to its pins. He replaced it with a properly wired external power supply that outputs a safe 5V DC, ensuring the display is now safe to use.