Looking at Ready-Made Add-On Boards
Many ready-made interface boards are available for the Raspberry Pi. These are designed to make things easier for you to do by building part of the circuits for you. They range from simply providing easier access to the GPIO pins, to including small sub circuits, to giving the Pi more inputs and outputs, or to performing special functions not available on the Pi directly, like being able to control the brightness of many LEDs. You can always incorporate these sub circuits into your projects when you need them, but these boards provide a shortcut to some projects by building them for you.
However, note that they are not essential and can be an expensive way of doing a project, mainly because they often contain more capabilities than you actually need for any one project. If you want to break up your project after you have finished it, you get value from these boards, but if you want to keep your projects and plug them in at any time to show others, you’re better off just building what you need. Dedicating a board to a project is an expensive way of doing things. All the projects in later chapters of this book are self-contained and do not require any third-party boards. However, some offer convenience that might be attractive to some people. New boards are constantly being developed and produced. In the next sections, we look at a few.
The Gert board
The Gert board is the granddaddy of expansion boards. It is the closest thing there is to an official ...