Hello friends! Today we will answer a basic question: what is Arduino, and how do we use it? If you have seen projects that read a sensor, flash an LED or move a small motor, you have probably encountered an Arduino board. This introduction explains the board, the program and the surrounding circuit as separate parts of one system. We will use the classic Arduino Uno R3 as our main example because many tutorials in this series use it. Arduino includes many other boards, so the Uno's processor, pin count and voltage must not be assumed to describe the entire platform. This article is the introduction to our Arduino Projects learning guide . By the end, you should understand what a sketch does, how it reaches the board, what the pins can do and how to choose a sensible first project. Figure: ...