The Arduino Uno-compatible board has an MCS-51 (often called 8051 instead) instead of the usual ATmega328P/ATmega168. Specifically, [ElectroBoy] uses the AT89S52 .

The Arduino Uno is connected to a RGB color sensor (e.g., TCS3200 or similar). The sensor reads the color values and sends them over serial communication to a Python script running on your computer.

Both the Arduino Nano and Uno can be powered via their integrated USB connectors. This automatically supplies regulated 5V power to the board, allowing you to use any USB-supported power source ...

The Arduino UNO R4 boasts a 3x performance increase over the UNO R3 and , in addition, SRAM has been upgraded from 2kB to 32kB, and flash memory from 32kB to 256kB to support more complex projects.