While there are lots of different Arduino boards, the Arduino UNO is by far the most popular. It contains an ATmega328 chip running at 16MHz, and it has 23 GPIO pins along with hardware peripherals such as serial communication ports and analog-capable pins. Each pin can perform several different functions depending on how it's configured via the code, and we'll look at the difference between analog and digital signals later on, but each pin can only perform one function at a time.

The Arduino UNO is a really simple board. It has a DC barrel jack for power, along with a regulator and filtering circuitry, a USB port for power and communicating with your board, pin headers, some LEDs and a reset button. The UNO provides a really good balance between size, features, power and cost, and is compatible with the standard Arduino hardware format known as Shields, which we'll cover further on in the course.

As we mentioned previously, for this course we'll be using the Sparkfun Inventors Kit, which contains a genuine Arduino UNO board. Now let's take a look at how we can get our code onto the board using the Arduino IDE.