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RGB LED

A versatile 4-pin LED that combines three separate LEDs (Red, Green, Blue) into a single package to produce millions of colors.

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RGB LED

An RGB LED is essentially three separate LEDs housed in one bulb. By using PWM (Pulse Width Modulation) on the R, G, and B pins, you can independently adjust the brightness of each color channel, mixing them to create almost any color imaginable.

DisplaysLightPWM

Overview

RGB LEDs come in two internal wiring configurations:

• Common Cathode: All three internal LEDs share a single Ground pin (COM). You turn a color ON by sending a HIGH signal (or PWM) to its respective pin.
• Common Anode: All three internal LEDs share a single VCC/5V pin (COM). You turn a color ON by pulling its respective pin LOW.

Note: You must use current-limiting resistors (usually 220Ω) on the R, G, and B pins, just like standard LEDs.

Pin Reference

Pin	Type	Description
R	digital	Red channel. Connect to a PWM pin (with resistor).
COM	power	Common pin. Connect to GND (Cathode) or 5V (Anode).
G	digital	Green channel. Connect to a PWM pin (with resistor).
B	digital	Blue channel. Connect to a PWM pin (with resistor).

Configurable Attributes

Attribute	Type	Default	Description
common	string	"cathode"	Configuration of the common pin: "cathode" or "anode".

Wiring Diagram

Connect the RGB LED to the Arduino using PWM pins to control colors.

Example Arduino Code

This code cycles through Red, Green, and Blue by writing PWM values (0-255) to a Common Cathode RGB LED.

#define PIN_R 9
#define PIN_G 10
#define PIN_B 11

void setup() {
  pinMode(PIN_R, OUTPUT);
  pinMode(PIN_G, OUTPUT);
  pinMode(PIN_B, OUTPUT);
}

void loop() {
  // Pure Red
  setColor(255, 0, 0);
  delay(1000);
  
  // Pure Green
  setColor(0, 255, 0);
  delay(1000);
  
  // Pure Blue
  setColor(0, 0, 255);
  delay(1000);
  
  // Yellow (Red + Green)
  setColor(255, 255, 0);
  delay(1000);
}

// Helper function to set the color
void setColor(int redValue, int greenValue, int blueValue) {
  analogWrite(PIN_R, redValue);
  analogWrite(PIN_G, greenValue);
  analogWrite(PIN_B, blueValue);
}

Simulation Notes

• The OpenHW Simulator fully supports PWM color mixing. Ensure you connect the R, G, and B pins to Arduino pins that have a ~ symbol (like 3, 5, 6, 9, 10, 11 on the Uno) to use analogWrite().

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