Arduino has shrunk the UNO R4 with the Arduino Nano R4 board equipped with the same 48 MHz Renesas RA4M1 32-bit Arm ...

The board is built around an ATtiny3217 and has almost all of the Nano’s features, like a USB port, reset button, built-in LEDs, 5 V regulator, and preloaded bootloader.

The build is open-source, and designed to work with strings of 60, 120, or 180 WS2812B LEDs. An Arduino Nano is charged with running the show, capturing audio via its analog-to-digital converter.