There are many different types of Arduino® projects in the world, and the thing most people love about Arduino® is that it can be used in a wide variety of ways. Some Arduino® projects focus on learning the basics of the system, but many take advantage of the main strength of this tool: its ability to interact with the physical world through sensors and clever physical setups. An Arduino® project can interact with the world in any number of ways, including reacting to physical variables, responding to switches, and even learning to accomplish a task. While many projects using this type of microcontroller are practical, there is usually a sense of fun in projects of this type.
Many Arduino® projects are ways of recreating common objects that people already use. These projects are valuable not only because they teach skills required for more complex designs, but also because they can form the basis for improvements to these basic objects. Flashing lights, stopwatches, and thermostats can all be made using this versatile tool. It is also possible to make simple games that play tic tac toe or run through a maze.
Some of the most common Arduino® projects take information about the world collected by sensors and cause the project to act on that information in some way. For example, a small robot with wheels might follow a painted black line, or an eye with a motion sensor might follow a person around. This type of project can be made in ways that are quite complex, and with a little ingenuity can accomplish highly complex tasks like brewing beer or making sandwiches.
Going the other direction, many Arduino® projects take information from a computer and direct a device to behave in a certain way. This means that a computer or phone can be used to control, for example, an RC car. Designs of this type also allow crafters to build email notifiers and other convenient devices.
There are certain types of Arduino® projects that require specific boards. For example, cloth projects typically require the LilyPad board. Some projects can work with a number of different boards depending on the designer's plans, but often require customization by the user.
Many Arduino® projects are created not to serve a specific function but rather to work as art. The artistic uses of microcontrollers are extremely broad and can often make the art interact with users or the environment. For this type of project, much of the design often relies on hiding the board and creating the illusion that the project is working by magic. Most people think of this type of Arduino® project as a sculpture or a machine.