# CONTROL 8 LED USING ARDUINO :-

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I hope you might have have practice my GETTING STARTED WITH ARDUINO #1 which showcased you the control of LED using Arduino.In this instructables i will teach how to control 8 Led simultaneously. so are you ready to build a colourful instructables??.Keep following for arduino ,HTML and CSS tutorial which will be published in a short while.

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## Step 1: ELECTRONICS REQUIRED :-

The most simple tools required for this colorful Instructables are:-

• Arduino uno
• Jumper wires
• LED

I am eagerly waiting to get started!!!!!!.

## Step 2: BUILDING ELECTRONICS :-

• Bend the cathode of all the 8 LED in such a way that the cathode is inserted in the power rail of the negative supply.Supply the ground pin from arduino to the negative railings
• The annode leg is connected to the digital pin of the Arduino[2,3,4,5,6,7,8,9]

it's finished now. let's get into the most difficult yet a easy task ' CODING '

## Step 3: CODING :-

//LED Pin Variables

int ledPins[] = {2,3,4,5,6,7,8,9}; //An array to hold the pin each LED is connected to //i.e. LED #0 is connected to pin 2, LED #1, 3 and so on //to address an array use ledPins[0] this would equal 2 //and ledPins[7] would equal 9

/* * setup() - this function runs once when you turn your Arduino on * We the three control pins to outputs */

void setup() {

//Set each pin connected to an LED to output mode (pulling high (on) or low (off)

for(int i = 0; i < 8; i++){

//this is a loop and will repeat eight times

pinMode(ledPins[i],OUTPUT); //we use this to set each LED pin to output } //the code this replaces is below

/* *

loop() - this function will start after setup finishes and then repeat * we call a function called oneAfterAnother(). if you would like a different behaviour * uncomment (delete the two slashes) one of the other lines */

void loop() // run over and over again {

oneAfterAnotherNoLoop(); //this will turn on each LED one by one then turn each off }

void oneAfterAnotherNoLoop()

{ int delayTime = 100; //the time (in milliseconds) to pause between LEDs //make smaller for quicker switching and larger for slower

digitalWrite(ledPins[0], HIGH); //Turns on LED #0 (connected to pin 2 )

delay(delayTime); //waits delayTime milliseconds

digitalWrite(ledPins[1], HIGH); //Turns on LED #1 (connected to pin 3 )

delay(delayTime); //waits delayTime milliseconds

digitalWrite(ledPins[2], HIGH); //Turns on LED #2 (connected to pin 4 )

delay(delayTime); //waits delayTime milliseconds

digitalWrite(ledPins[3], HIGH); //Turns on LED #3 (connected to pin 5 )

delay(delayTime); //waits delayTime milliseconds

digitalWrite(ledPins[4], HIGH); //Turns on LED #4 (connected to pin 6 )

delay(delayTime); //waits delayTime milliseconds

digitalWrite(ledPins[5], HIGH); //Turns on LED #5 (connected to pin 7 )

delay(delayTime); //waits delayTime milliseconds

digitalWrite(ledPins[6], HIGH); //Turns on LED #6 (connected to pin 8 )

delay(delayTime); //waits delayTime milliseconds

digitalWrite(ledPins[7], HIGH); //Turns on LED #7 (connected to pin 9 )

delay(delayTime); //waits delayTime milliseconds

//Turns Each LED Off

digitalWrite(ledPins[7], LOW); //Turns on LED #0 (connected to pin 2 )

delay(delayTime); //waits

delayTime milliseconds

digitalWrite(ledPins[6], LOW); //Turns on LED #1 (connected to pin 3 )

delay(delayTime); //waits delayTime milliseconds

digitalWrite(ledPins[5], LOW); //Turns on LED #2 (connected to pin 4 )

delay(delayTime); //waits delayTime milliseconds

digitalWrite(ledPins[4], LOW); //Turns on LED #3 (connected to pin 5 )

delay(delayTime); //waits delayTime milliseconds

digitalWrite(ledPins[3], LOW); //Turns on LED #4 (connected to pin 6 )

delay(delayTime); //waits delayTime milliseconds

digitalWrite(ledPins[2], LOW); //Turns on LED #5 (connected to pin 7 )

delay(delayTime); //waits delayTime milliseconds

digitalWrite(ledPins[1], LOW); //Turns on LED #6 (connected to pin 8 )

delay(delayTime); //waits delayTime milliseconds

digitalWrite(ledPins[0], LOW); //Turns on LED #7 (connected to pin 9 )

delay(delayTime); //waits delayTime milliseconds }

void oneAfterAnotherLoop(){

int delayTime = 100; //the time (in milliseconds) to pause between LEDs //make smaller for quicker switching and larger for slower

//Turn Each LED on one after another

for(int i = 0; i <= 7; i++){

digitalWrite(ledPins[i], HIGH); //Turns on LED #i each time this runs i

delay(delayTime); //gets one added to it so this will repeat } //8 times the first time i will = 0 the final //time i will equal 7;

//Turn Each LED off one after another

for(int i = 7; i >= 0; i--){ //same as above but rather than starting at 0 and counting up //we start at seven and count down

digitalWrite(ledPins[i], LOW); //Turns off LED #i each time this runs i

delay(delayTime); //gets one subtracted from it so this will repeat } //8 times the first time i will = 7 the final //time it will equal 0 }

/* * oneOnAtATime() - Will light one LED then the next turning off all the others */

void oneOnAtATime(){

int delayTime = 100; //the time (in milliseconds) to pause between LEDs //make smaller for quicker switching and larger for slower

for(int i = 0; i <= 7; i++){

int offLED = i - 1; //Calculate which LED was turned on last time through

if(i == 0) { //for i = 1 to 7 this is i minus 1 (i.e. if i = 2 we will offLED = 7; //turn on LED 2 and off LED 1) } //however if i = 0 we don't want to turn of led -1 (doesn't exist) //instead we turn off LED

7, (looping around)

digitalWrite(ledPins[i], HIGH); //turn on LED #i

digitalWrite(ledPins[offLED], LOW); //turn off the LED we turned on last time

delay(delayTime); } }

/* * inAndOut() - This will turn on the two middle LEDs then the next two out * making an in and out look */

void inAndOut(){

int delayTime = 100; //the time (in milliseconds) to pause between LEDs //make smaller for quicker switching and larger for slower //runs the LEDs out from the middle

for(int i = 0; i <= 3; i++){

int offLED = i - 1; //Calculate which LED was turned on last time through

if(i == 0) { //for i = 1 to 7 this is i minus 1 (i.e. if i = 2 we will

offLED = 3; //turn on LED 2 and off LED 1) } //however if i = 0 we don't want to turn of led -1 (doesn't exist) //instead we turn off LED 7, (looping around)

int onLED1 = 3 - i; //this is the first LED to go on ie. LED #3 when i = 0 and LED //#0 when i = 3 int onLED2 = 4 + i; //this is the first LED to go on ie.

LED #4 when i = 0 and LED //#7 when i = 3

int offLED1 = 3 - offLED; //turns off the LED we turned on last time

int offLED2 = 4 + offLED; //turns off the LED we turned on last time

digitalWrite(ledPins[onLED1], HIGH);

digitalWrite(ledPins[onLED2], HIGH);

digitalWrite(ledPins[offLED1], LOW);

digitalWrite(ledPins[offLED2], LOW);

delay(delayTime); }

//runs the LEDs into the middle

for(int i = 3; i >= 0; i--){

int offLED = i + 1; //Calculate which LED was turned on last time through

if(i == 3) { //for i = 1 to 7 this is i minus 1 (i.e.

if i = 2 we will

offLED = 0; //turn on LED 2 and off LED 1) } //however if i = 0 we don't want to turn of led -1 (doesn't exist) //instead we turn off LED 7, (looping around)

int onLED1 = 3 - i; //this is the first LED to go on ie. LED #3 when i = 0 and LED //#0 when i = 3 int onLED2 = 4 + i; //this is the first LED to go on ie. LED #4 when i = 0 and LED //#7 when i = 3 i

nt offLED1 = 3 - offLED; //turns off the LED we turned on last time

int offLED2 = 4 + offLED; //turns off the LED we turned on last time

digitalWrite(ledPins[onLED1], HIGH);

digitalWrite(ledPins[onLED2], HIGH);

digitalWrite(ledPins[offLED1], LOW);

digitalWrite(ledPins[offLED2], LOW);

delay(delayTime); }

}

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