DIY Colour-Changing RGB LED with Arduino and OLED Display

The DIY Colour-Changing RGB LED with Arduino and OLED Display project operates by coordinating visual output between an Arduino Uno microcontroller, an RGB LED, and an I2C-driven SSD1306 OLED screen. At the heart of the system is the Arduino Uno, which executes a programmed loop to control both the color of the LED and the text rendered on the display. The common-cathode RGB LED shares a single negative ground connection, while its individual red, green, and blue anode legs are connected to digital pins on the Arduino through 220-ohm current-limiting resistors. These resistors are vital for protecting the internal diodes of the LED by restricting current flow from the microcontroller outputs. By varying the state or analog output of the control pins, the Arduino mixes different intensities of red, green, and blue light to generate a spectrum of distinct colors. Every five seconds, the internal timer triggers a state change in the software loop. Simultaneously, the Arduino communicates with the SSD1306 OLED display over the I2C protocol, sending textual data that corresponds to the newly selected LED color. The OLED screen updates its pixel matrix to show the active color name, providing a synchronized visual readout that matches the physical illumination of the LED. Power is supplied either via the USB cable during programming or independently in the field using a 9V battery with a compatible connector, allowing the circuit to operate as a standalone interactive display unit.