TITLE: Blinking the LED on Arduino
AUTHOR: Chuck McManis
LAST UPDATE: 24-May-2014


This is the standard Blink.cpp example from the Arduino software. It uses information about specific pins and chips used in the Arduino to define a number of constants that are required for any blink program. In particular it uses a GPIO pin #13 as the LED target, because all Arduinos have an LED attached to that GPIO. It uses library specific code for doing a delay so that the LED will blink in a human visible way.

The Source Code

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

// Pin 13 has an LED connected on most Arduino boards.
// give it a name:
int led = 13;

// the setup routine runs once when you press reset:
void setup() {
  // initialize the digital pin as an output.
  pinMode(led, 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(1000);               // wait for a second
  digitalWrite(led, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);               // wait for a second


Creative Commons License

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