This minimalist beauty uses an Arduino Nano and RGB sensor to assess the color. At the top, a small servo rotates an arm inside the hopper that both shakes the Skittles and sets them up single ...

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.

Researchers from the University of Johannesburg in South Africa have developed a cleaning system for solar modules based on the TCS3200 color sensor and the Arduino Uno open-source microcontroller.