In this lesson you will learn how to blink the LED on the Arduino Board. The Arduino has a single LED that you can control from your programs also called sketches. This LED is built onto the Arduino board and is often referred to as the 'L' LED as this is how it is labelled on the board.

The position of this LED is circled in red on the picture of the Arduino Uno below.

arduino - blink a led

Load the 'Blink' sketch that you will find in the IDE's menu system under File → Examples → 01.Basics

 arduino lesson2 1

When the sketch window opens, enlarge it so that you can see the whole of the sketch in the window.

arduino - blink a led

Click on the 'Upload' button. The second button from the left on the toolbar.

arduino - blink a led

Then you will see a progress bar and a series of messages. At first it will say 'Compiling Sketch..'. This converts the sketch into a format suitable for uploading to the board.

arduino lesson2 4

Once the upload has completed, the board should restart and the LED start blinking

 Now you can experiment by changing the delay time so tat the LED will blink slower or faster.