You can also find the Raspberry Pi for sale on eBay. There are usually plenty of listings for just a Raspberry Pi or for bundles that include all the accessories you need in order to hook it up.
Discovering What You Can and Can’t Do with a Raspberry Pi
This book shows you how to get going with Raspberry Pi projects. After you’ve done some, you’ll have a pretty good idea of what’s possible. But when you want to go a bit further with your ideas, it’s good to know what you can realistically expect to achieve.
The first thing you see when you get up and running is a text-based prompt on the screen. You can do a lot of things just with text, but most people prefer to launch the familiar graphical user interface (GUI), the desktop environment you’re used to on any other computer. The operating system supports all the things you’d want to do in a desktop system, including playing games, browsing the web, word processing, using spreadsheets, editing photos, and playing audio and video.
But that’s not where the Raspberry Pi really shines. The great things you can do with the Pi come into play when you write your own programs and hook it up to electronics or other objects in the real world using the general-purpose input/output (GPIO) connector. Your Pi is well suited for this because these kinds of things don’t usually require the beefy processor in your desktop or laptop. Using your Pi for things you may not do with your usual computer is what makes it really fun – and that’s what this book is all about!
The Raspberry Pi uses a Broadcom BCM2835 central processing unit (CPU) and a VideoCore IV graphics processing unit (GPU) and shares the onboard memory between them. Either 256MB or 512MB of onboard memory is available. The CPU is an impressive piece of technology that enables fairly complex computing power at an extremely low price. The trade-off is that the Pi is not nearly as powerful as the full-fledged CPU in desktop and laptop computers – it’s a bit slower, roughly comparable to the capabilities of mainstream computers in the ’90s. You shouldn’t plan to do high-performance computing or run heavily graphics-intensive applications like gams or 3D modeling software – the Pi will run these, but they may be unusably slow.
You probably won’t be replacing your main computer with a Pi, but you can do a lot of experimentation with it that you may not try with your desktop or laptop, and you can easily connect your Raspberry Pi to sensors and motors in the real world, which we show you how to do in the projects in this book. And if you make any big mistakes that damage your Pi, it doesn’t cost a lot to get another one and start experimenting again!
Getting Familiar with Your Raspberry Pi
The Raspberry Pi is about the size of a credit card and has all the components that you need onboard so that you can connect it to a TV or display and start using it. These connections are shown in Figure 1-3.
Figure 1-3: Identifying the parts of the Raspberry Pi (in this case, the Model B).
Going clockwise around the board from the top left, you’ll find the following connections:
✔ General-purpose input/output (GPIO) connector: This is a port for getting electrical signals into and out of your Raspberry Pi, such as for reading sensors and controlling motors. It’s composed of two parallel rows of pins and is labeled P1 (for “Plug 1”). Different models of Raspberry Pi use these pins slightly differently due to the way the pins are routed on the board.
✔ Composite video output: This jack is used for connecting your Raspberry Pi to a composite video (standard TV) connection using an RCA cable.
✔ Audio output: This is a black 3.5mm jack on the upper right of the board.
✔ USB port(s): These ports allow you to connect USB accessories (such as a keyboard and mouse and external storage devices) to your board. The Model A has only one USB port to reduce costs. The Model B has two USB ports.
✔ Ethernet port (Model B only): This port is for connecting your Raspberry Pi to an Ethernet network and for accessing the Internet.
✔ Camera serial interface (CSI) connector: This slim black connector between the Ethernet jack and the HDMI output is for connecting a small camera such as a webcam. CSI connectors are available from the Raspberry Pi store.
✔ HDMI output: This port is used for sending digital video to a computer monitor. The HDMI output also can route your audio, so you may not need to use the audio output port.
✔ Power input: On the lower-left side is the micro USB power socket. The power is provided via a micro USB power supply that plugs into this port.
✔ Display serial interface (DSI) connector: In the middle of the left side of the board is a slim connector for connecting high-speed displays. It’s used for connecting a small LCD panel directly to your Raspberry Pi. You can use it for touch-based input as well!
Selecting Your Accessories
You probably have some of the important accessories lying around the house already, which was exactly what its creators had in mind. You can just use old stuff that’s gathering dust – you don’t have to buy anything, which keeps the cost down. You don’t have to get all the accessories shown in Figure 1-4 to complete the projects in this book. But at a bare minimum, you’ll need a display and a keyboard to get things going. Here’s what you see in Figure 1-4:
✔ Monitor: The Raspberry Pi’s onboard HDMI output allows you to connect a high-definition feed to just about any modern computer display. If your display has an HDMI input, all you need is a cable between the two.
If your monitor doesn’t have an HDMI input, it probably supports DVI, which has a larger, wider connector. You can buy adapters that convert from HDMI to DVI that will allow you to use your DVI monitor. You can also use a VGA monitor (the VGA input contains three rows of holes), though these aren’t officially supported. If you want to use VGA, make sure to get an adapter that is specifically meant to work with a Raspberry Pi.
✔ Ethernet cable: Some of the projects in this book require connecting your Raspberry Pi to a network. For these projects, you’ll need an Ethernet cable.
✔ Case: You can use your Raspberry Pi as is, right out of the box. It’s pretty durable, but accidents happen, so lots of people have fun making cool cases to protect the circuit board from spills and dust. Some cases are even enhanced with glowing LEDs. The designer of the Raspberry Pi logo, Paul Beech, has designed some cool cases – check out http://shop.pimoroni.com to find them.
✔ Mouse: Any USB mouse will work fine. The Model A only has one USB port, so if you’re using a Model A, you’ll need to use a USB hub so that you can plug in both your mouse and your keyboard. You can also plug your mouse into your keyboard, if the keyboard has an extra USB port on it.
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