For the first time, we are introducing a program to control what the Arduino does! It is one of the simplest possible programs, but it showcases many of the features of the programming environment, the language and the Arduino itself.
This project also has the simplest possible hardware configuration; there is nothing to wire, and no breadboard is needed. We will only need the Arduino itself, connected to your computer by the USB cable.
This project makes use of the Arduino's onboard LED, which is highlighted in the Fritzing diagram for this project. While there are four LEDs total on the Arduino, this is the one you can control by code when you program your Arduino.
The program will blink the onboard LED of the Arduino at one-second intervals: one second on, one second off, repeatedly, for as long as the Arduino has power.
You can also practice your coding skills a bit by changing the length of either the ON time or the OFF time, or both. We will show you how to do that in the Arduino Web Editor.