There are a number of different official Arduino boards and modules that can be used for various purposes. To see all the different boards, you can go to that Arduino product page (https://www.arduino.cc/en/Main/Products) where they list all the official Arduino boards.

While the Arduino Uno R3 is the most popular Arduino board within the maker community, the following lists some of the other popular boards:

The Arduino Micro is the smallest board in the Arduino family. It is based on the ATmega32U4 microcontroller. This board features 20 digital I/O pins of which 7 can be used for PWM output and 12 can be used as analog input. The Micro and the Nano (which we will see a little later) can be used for a project where the Arduino Uno may be too big.

The Arduino Mega 2560 is designed for the most complex projects. It features 53 digital I/O pins, 16 analog input pins and 15 PWM output pins. It also has 4 serial UARTs for serial connections. If you want to create a complex project like a robot, the Mega is the board you will want to start with.

The Arduino Lilypad is designed for wearable projects. It can be sewn into fabrics and use power supplies and sensors that are also sewn into fabrics. The Lilypad is based on the ATmega168V or ATmega328V (low power versions). This board features 16 digital I/O, 6 analog inputs and 6 PWM outputs.

There are a lot of similarities between the Nano and the Micro. The Micro was released in 2012 while the Nano was released in 2008. The Nano features 14 digital I/O pins, 8 analog input pins and 6 PWM output pins. With those specifications, you may think that you should use the Micro board over the Nano however if you look at most online retailers like Amazon or eBay you can find the Nano for about half the price of the Micro.

You will also find that the Nano is easier to obtain than the Micro because there are so many generic Nano boards. We will also be using the Nano for some of the projects in this book.

At the beginning of this book, we noted that the Arduino is an open source hardware and software platform. All the original hardware design files are released under the Creative Commons Attribution Share-Alike license. This license allows both personal and commercial derivatives of all the Arduino boards if they credit Arduino and release their design under the same license. This has led to many lower price generic boards.

If you search for an Arduino board on most online retailer sites, the majority of the boards will not actually be genuine Arduino boards. If you look at the Arduino Uno board in the following photograph, you will notice an infinity sign with a plus (+) and minus (-) in it. That is the official Arduino logo and any board that has this logo is a genuine Arduino board.

In this book, we will be using mostly generic Arduino boards as they are cheaper and usually easier to obtain. The following photograph shows what some generic Arduino boards look like. The first photograph shows two generic Arduino Uno boards:

The next photograph shows a generic Arduino Mega 2560 board:

You will notice that these generic boards do not contain the Arduino logo; however, they still contain the name of the official board. While the previous generic boards look very similar to the official Arduino boards, that is not required. Some manufacturers chose to take the Arduino reference design and add additional functionality to their boards. The board in the following photograph is an example of this:

The DFRobot RoMeo BLE board is an Arduino-compatible robot control board with Bluetooth LE 4.0. This board takes the design of the Arduino Uno and adds a number of extra features, such as built-in Bluetooth and an integrated two-way DC motor driver.

No matter what your project is, you can probably find either a genuine Arduino board or a generic/compatible one that will fit your needs.