Published January 20, 2022

Interfacing RGB Led with Arduino

In this project, we will learn how to interface RGB LED with Arduino Uno. The RGB LED is controlled by PWM signals.

BeginnerProtip1,089

Things used in this project

Hardware components

Arduino UNO

RGB Diffused Common Cathode

RGB Diffused Common Anode

Resistor 220 ohm

Jumper wires (generic)

Breadboard (generic)

Software apps and online services

Arduino IDE

Story

This project is made for Arduino beginners who are looking for learning how to interface the RGB led with the Arduino Uno. Also, we will understand the Common Anode (CA) and Common Cathode (CC) concept as well as the pulse width modulation (PWM) signals.

RGB LED Types and Structure

RGB LEDs have three LEDs inside them and usually, these three internal LEDs share either a common anode or a common cathode especially in a through-hole package. So basically, we can categorize RGB LEDs as either common anode or common cathode type just like in seven segment displays.

Common Anode

In a common anode RGB LED, the anode of the internal LEDs are all connected to the external anode lead. To control each color, you need to apply a LOW signal or ground to the red, green, and blue leads and connect the anode lead to the positive terminal of the power supply.

Common Cathode

In a common cathode RGB LED, the cathode of the internal LEDs are all connected to the external cathode lead. To control each color, you need to apply a HIGH signal or VCC to the red, green, and blue leads and connect the anode lead to the negative terminal of the power supply.

Basics of PWM (Pulse Width Modulation)

Pulse Width Modulation, or PWM, is a technique for getting analog results with digital means. Digital control is used to create a square wave, a signal switched between on and off. This on-off pattern can simulate voltages in between the full Vcc of the board (e.g., 5 V on UNO, 3.3 V on a MKR board) and off (0 Volts) by changing the portion of the time the signal spends on versus the time that the signal spends off. The duration of "on time" is called the pulse width. To get varying analog values, you change, or modulate, that pulse width. If you repeat this on-off pattern fast enough with an LED for example, the result is as if the signal is a steady voltage between 0 and Vcc controlling the brightness of the LED. In the graphic below, the green lines represent a regular time period. This duration or period is the inverse of the PWM frequency. In other words, with Arduino's PWM frequency at about 500Hz, the green lines would measure 2 milliseconds each.

Code

Code

// *Interfacing RGB LED with Arduino 
// * Author: Osama Ahmed 

//Defining variable and the GPIO pin on Arduino
int redPin= 5;
int greenPin = 6;
int bluePin = 7;

void setup() {
  //Defining the pins as OUTPUT
  pinMode(redPin, OUTPUT);              
  pinMode(greenPin, OUTPUT);
  pinMode(bluePin, OUTPUT);
}
void loop() {
  setColor(255, 0, 0); // Red Color
  delay(1000);
  setColor(0, 255, 0); // Green Color
  delay(1000);
  setColor(0, 0, 255); // Blue Color
  delay(1000);
  setColor(255, 255, 255); // White Color
  delay(1000);
  setColor(170, 0, 255); // Purple Color
  delay(1000);
  setColor(127, 127, 127); // Light Blue
  delay(1000);
}
void setColor(int redValue, int greenValue, int blueValue) {
  analogWrite(redPin, redValue);
  analogWrite(greenPin, greenValue);
  analogWrite(bluePin, blueValue);
}

Interfacing RGB Led with Arduino

Things used in this project

Hardware components

Software apps and online services

Story

Schematics

Schematic for the project

Code

Code

Credits

semsemharaz

Comments

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Interfacing RGB Led with Arduino

Interfacing RGB Led with Arduino

Things used in this project

Hardware components

Software apps and online services

Story

Schematics

Schematic for the project

Code

Code

Credits

semsemharaz

Comments

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