You can throw a Raspberry Pi camera and OpenCV at the problem and approach it through software, or you can buy an off-the-shelf RGB sensor and wire it up to an Arduino.

Arduino has launched its next generation of UNO boards, introducing a 32-bit Renesas microcontroller and Espressif ESP32-S3 module, one-click cloud connectivity and plenty of I/O plus a 12×8 red LED ...