Arduino Group Dimming Tutorial

ARDUINO GROUP DIMMING TUTORIAL

INTRODUCTION

Arduino is a microcontroller which can be programmed to do certain operations like lighting led, controlling servo, etc. This is a DIY Arduino project intended to achieve group dimming of LED’s. The group dimming or segregated dimming gives the flexibility of dimming a batch of LED’s at a time rather than dimming all at once. Group dimming is best observed during light shows where different colors of lights fade at different time. Dimming or fading is a process of gradually increasing or decreasing the brightness of light. The group dimming setup consists of 9 LED’s (3 each of red, white and blue). The 3 LED’s switch on and off gradually within a specified time. The delay time or the time interval used here is 200 millisecond.  

COMPONENTS REQUIRED

1. Perfboard and Breadboard

2. Arduino Mega 2560 and USB cable

3. 5mm Red LED’s (3)

4. 5mm White LED’s (3)

5. 5mm Blue LED’s (3)

6. 20 Ohm resistors (9)

7. Jumpers

8. A 5V DC Power supply

CIRCUIT SCHEMATICS

Fig1 Group dimming schematic

Make the appropriate connections as shown in the schematic above

CODE

This is the code for simulating Group fading or dimming of LED’s. Note that this code is valid only for the particular schematic represented in figure1. The values and choice of ports can always be changed but ensure only analog pins or PWM pins are selected. Analog pins are usually marked with a ‘~’ in front of the pin number. You must use Arduino Mega Board since it contains 12 PWM pins and we require 9 PWM pins. Copy and paste the code in Arduino IDE sketch area.

/*

Group LED dimming/fading

This example shows how to fade LED in groups

use Arduino mega, it has PWM pins 2 through 13

Created by Srinath Srinivasan

This code is in the public domain

*/

int ledPin1 = 2;    // LED connected to PWM pin 2

int ledPin2 = 3;    // LED connected to PWM pin 3

int ledPin3 = 4;    // LED connected to PWM pin 4

int ledPin4 = 5;    // LED connected to PWM pin 5

int ledPin5 = 6;    // LED connected to PWM pin 6

int ledPin6 = 7;    // LED connected to PWM pin 7

int ledPin7 = 8;    // LED connected to PWM pin 8

int ledPin8 = 9;    // LED connected to PWM pin 9

int ledPin9 = 10;   // LED connected to PWM pin 10

void setup() {

  // nothing happens in setup

}

void loop() {

  // fade in from min to max in increments of 5 points:

  for (int fadeValue = 0 ; fadeValue <= 255; fadeValue += 5) {

    // sets the value (range from 0 to 255):

    analogWrite(ledPin1, fadeValue);

    analogWrite(ledPin2, fadeValue);

    analogWrite(ledPin3, fadeValue);

    // wait for 200 milliseconds to see the dimming effect

    delay(200);

  }

 

  for (int fadeValue = 0 ; fadeValue <= 255; fadeValue += 5) {

    // sets the value (range from 0 to 255):

    analogWrite(ledPin4, fadeValue);

    analogWrite(ledPin5, fadeValue);

    analogWrite(ledPin6, fadeValue);

    // wait for 200 milliseconds to see the dimming effect

    delay(200);

  }

 

  for (int fadeValue = 0 ; fadeValue <= 255; fadeValue += 5) {

    // sets the value (range from 0 to 255):

    analogWrite(ledPin7, fadeValue);

    analogWrite(ledPin8, fadeValue);

    analogWrite(ledPin9, fadeValue);

    // wait for 200 milliseconds to see the dimming effect

    delay(200);

  }

  // fade out from max to min in increments of 5 points:

  for (int fadeValue = 255 ; fadeValue >= 0; fadeValue -= 5) {

    // sets the value (range from 0 to 255):

    analogWrite(ledPin1, fadeValue);

    analogWrite(ledPin2, fadeValue);

    analogWrite(ledPin3, fadeValue);

    // wait for 200 milliseconds to see the dimming effect

    delay(200);

  }

 

  for (int fadeValue = 255 ; fadeValue >= 0; fadeValue -= 5) {

    // sets the value (range from 0 to 255):

    analogWrite(ledPin4, fadeValue);

    analogWrite(ledPin5, fadeValue);

    analogWrite(ledPin6, fadeValue);

    // wait for 200 milliseconds to see the dimming effect

    delay(200);

  }

 

  for (int fadeValue = 255 ; fadeValue >= 0; fadeValue -= 5) {

    // sets the value (range from 0 to 255):

    analogWrite(ledPin7, fadeValue);

    analogWrite(ledPin8, fadeValue);

    analogWrite(ledPin9, fadeValue);

    // wait for 200 milliseconds to see the dimming effect

    delay(200);

  }

}