How to control 8 leds using Arduino UNO

hey guys this is my first arduino project  plz  comment how u feel.

Step 1: Things u need

As this is easy project for beginner’s so parts are also simple
1- Arduino uno or any other board will work
9- jumper wires or wires will also do
8 -leds any color u like i used 3 red, 3 green and 2 blue
8- 1k resistors

Arduino control 8 leds

Step 2: Placing the leds and wiring

In this step u have to place the leds on the bread board i have kept the positive  wire on the right side .
Next wire them as shown in

Step 3: Uploading the code

//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

Arduino control 8 leds connection

* 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

READ  Capacitive touch Mood light using Arduino


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

Major Components in Project

1- Arduino uno or any other board will work


For more detail: How to control 8 leds using Arduino UNO

This Post / Project can also be found using search terms:

  • arduino projects 2 controlling 8 leds
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