Arduino Hello World Blink Code

This is a basic example how arduino works. In this arduino projects you’ll see how arduino control LED on for 1 second and off for 1 second repeatedly.

Instruction;
1) Connect cathode lead of LED (shorter lead) to ground pin and anode lead of LED (longer lead) to pin 13.

Upload this code to your arduino

/*
Blink
Turns on an LED on for one second, then off for one second, repeatedly.This example 
code is in the public domain.

Code hosted at: arduinoprojects101.com
*/

void setup() {
// initialize the digital pin as an output.
// Pin 13 has an LED connected on most Arduino boards:
pinMode(13, OUTPUT);
}

void loop() {
digitalWrite(13, HIGH);   // set the LED on
delay(1000);              // wait for a second
digitalWrite(13, LOW);    // set the LED off
delay(1000);              // wait for a second
}

There is 2 section of code arduino running, first setup() function which run once and second loop() function running continuously.

In setup function pinMode 13 declare as OUTPUT.

For more detail: Arduino Hello World Blink Code