There’s still plenty of useful hardware out there that uses an RS-232 interface, like the Behringer ... Inside the SerialChiller is an ESP32, a MAX3232 line driver, a LM1117 linear regulator ...

To achieve this he created Fade, a custom programming language/framework for controlling LED animations from the ESP32. Fade is written for addressable RGB LEDs like the Neopixel/WS2812.