Instructables
Picture of Multiple Blinking LED on the Arduino
In this tutorial I will show you how to make multiple LEDs blink with Arduino.  You will need three LEDs, jumper wires, breadboard, and Arduino.
 
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Step 1: Program The Arduino

Picture of Program The Arduino
Now you will need to paste the following code into the Arduino software and upload it to the Arduino.

int led = 13;
int led2 = 12;
int led3 = 11;

// the setup routine runs once when you press reset:
void setup() {               
  // initialize the digital pin as an output.
  pinMode(led, OUTPUT);
  pinMode(led2, OUTPUT);
pinMode(led3, OUTPUT); 
}

// the loop routine runs over and over again forever:
void loop() {
  digitalWrite(led, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(100);               // wait for a second
  digitalWrite(led, LOW);    // turn the LED off by making the voltage LOW
  delay(100); 
  {digitalWrite(led2, HIGH);
delay(100);
digitalWrite(led2, LOW);
delay(100);}
{digitalWrite(led3, HIGH);
delay(100);
digitalWrite(led3, LOW);
delay(100);}// wait for a second
}

Step 2: Connecting GND

Picture of Connecting GND
First connect a jumper wire from GND to the negative rail on the breadboard.

Step 3: Connecting the LEDs.

Picture of Connecting the LEDs.
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Then plug in the other jumper wires like this:
First, plug a wire from 13 on the Arduino to the top row on the breadboard.
Next, plug a wire from 12 on the Arduino to the top row on the breadboard.
Then plug a wire from 11 on the Arduino to the top row on the breadboard.
Space these out well. Use the picture to help you.
Now connect a wire going from the negative rail to the right of the other wires on the breadboard.
Lastly, put the longer leg of the Led (+) under the wire that goes to the Arduino. The shorter leg of the LED goes under the port that connects to the negative rail.

Step 4: Video of it Working

Picture of Video of it Working
maxyfun3 months ago

Perhaps you can help me

Im looking for code that will switch an LED on then off withing a single loop

without using the delay() function. Everywhere I look there are modified versions of the 'blink without delay' however they all have the same issue

loop starts the use millis() and a few variable to check the state if its high or low then swop the state over but only swops it once so the loop runs it switches on then the loop has to run a second time before it switches off. Any ideas?

http://arduino.cc/en/Reference/analogWrite

using the analog pins should help with your problem.

Hi, could you explain why we would list int led = 13; and not int led 1 = 13
I know default 13 is a blink led , is that why ?
Can we use 13 for other things , what do we have to do different while addressing pin 13?
Thanks.

int led = 13;
int led2 = 12;
int led3 = 11;

mralr7 months ago

worked! thanks

cwolter978 months ago
I would just like to say I hope you know the comments are incorrect about the length of time the delays are.

The delay you have it set to is to delay for 1/10 of a second
The Electrodog Show (author) 11 months ago
Thanks! Glad it worked.
o__o1 year ago
Thanks! This is explained perfectly, this is my first aduino project ever and it turned out beautifully!