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RGB LED Color Mixing (Arduino)

Cycle an RGB LED through colors with PWM on three pins. Learn analogWrite and color mixing.

Beginner20 min

What you need

Wiring

Arduino Uno
RGB LED

Hover a pin or a wire to trace the connection.

Code

rgb_fade.ino
// Cycle an RGB LED through colors using PWM.
// Wiring below is for a COMMON-CATHODE LED. For common-anode, use 255 - value.
const int R = 9, G = 10, B = 11;  // PWM pins (~)

void setColor(int r, int g, int b) {
  analogWrite(R, r); analogWrite(G, g); analogWrite(B, b);
}

void setup() {
  pinMode(R, OUTPUT); pinMode(G, OUTPUT); pinMode(B, OUTPUT);
}

void loop() {
  setColor(255, 0, 0);   delay(500); // red
  setColor(0, 255, 0);   delay(500); // green
  setColor(0, 0, 255);   delay(500); // blue
  setColor(255, 255, 0); delay(500); // yellow
  setColor(0, 255, 255); delay(500); // cyan
  setColor(255, 0, 255); delay(500); // magenta
}

Steps

  1. Wire each color pin (R/G/B) from D9/D10/D11 through its own 220Ω resistor.
  2. Connect the common (longest) leg to GND for a common-cathode LED.
  3. Upload to cycle colors. If colors look inverted, you have a common-anode LED — use 255 - value.