Arduino Basics: Blink
What is the first sketch to try?
The first program most beginners try is the Blink sketch. It demonstrates how to control a digital output pin by turning the onboard LED on and off at regular intervals.
How do I load the Blink example?
In the Arduino IDE, go to File → Examples → 01.Basics → Blink. This will open the Blink sketch in a new window or just copy the following:
/*
Blink
Turns an LED on for one second, then off for one second, repeatedly.
Most Arduinos have an on-board LED you can control. On the UNO, MEGA and ZERO
it is attached to digital pin 13, on MKR1000 on pin 6. LED_BUILTIN is set to
the correct LED pin independent of which board is used.
If you want to know what pin the on-board LED is connected to on your Arduino
model, check the Technical Specs of your board at:
https://docs.arduino.cc/hardware/
modified 8 May 2014
by Scott Fitzgerald
modified 2 Sep 2016
by Arturo Guadalupi
modified 8 Sep 2016
by Colby Newman
This example code is in the public domain.
https://docs.arduino.cc/built-in-examples/basics/Blink/
*/
// the setup function runs once when you press reset or power the board
void setup() {
// initialize digital pin LED_BUILTIN as an output.
pinMode(LED_BUILTIN, OUTPUT);
}
// the loop function runs over and over again forever
void loop() {
digitalWrite(LED_BUILTIN, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(LED_BUILTIN, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second
}How do I upload the sketch?
Connect your Arduino board to your computer using a USB cable. Then select the correct board and COM port under Tools, click Upload, and wait for the LED to start blinking.
How can I change the blink speed?
In the code, the delay() function controls how long the LED stays on or off. The number inside delay() is in milliseconds (1000 = 1 second).
delay(1000); // LED on or off for 1 secondTry using smaller values like delay(200) for a faster blink or larger ones for a slower effect.