Arduino Tri-colour LED Flasher Circuit

Created on: 8 May 2013

This simple tri-colour LED flasher circuit is great for beginners. The three pin tri-colour LED is controller by an Arduino Uno and changed between three colours.

This video shows the Arduino running a sketch that controls the tri-colour LED.

Circuit Diagram for the Arduino Tri-colour LED Controller

The circuit is very simple, using only three components. The tri-colour LED is a three pin common cathode type containing a red and green LED.

The tri-colour LED is the same LED used in the tri-colour LED transistor flasher circuit – refer to this project for more details on the LED.

Arduino tri-colour LED flasher circuit.
Arduino Tri-Colour LED Flasher Circuit

Arduino Sketch

The sketch changes the colour of the LED every second. Colours are changed by switching on the red LED in the tri-colour LED package, then the green LED, orange is obtained by switching on both the red and green LEDs at the same time.

  Program:      tri_colour_LED

  Description:  Changes the colours of a tri-color LED.
  Hardware:     Arduino Uno and tri-colour LED.
  Software:     Developed using Arduino 1.0.3 software
                Should be compatible with Arduino 1.0 +

  Date:         8 May 2013
  Author:       W.A. Smith,

void setup()
    pinMode(2, OUTPUT);
    pinMode(3, OUTPUT);

void loop()
    digitalWrite(2, HIGH);
    digitalWrite(3, LOW);
    digitalWrite(2, LOW);
    digitalWrite(3, HIGH);
    digitalWrite(2, HIGH);
    digitalWrite(3, HIGH);