In this book, we offer guidance on older models where possible but will assume you're using at least a Model B+ for the projects. For best performance, we recommend using a current model, if possible.
You’ll also see the Raspberry Pi Compute Module in the online stores alongside the Raspberry Pi, but this is something quite different. It’s aimed at engineers creating industrial applications (known as embedded systems) or products based on Raspberry Pi technology. We only mention it here in case you wonder what it is: It’s not covered further in this book, and it’s almost certainly not what you want to buy for your first Raspberry Pi.
Instead of running Windows or Mac OS, the Raspberry Pi uses an operating system called Linux. It’s a leading example of open source, a completely different philosophy to the commercial software industry. Rather than being created within the heavily guarded walls of a company, with its design treated as a trade secret, Linux is built by companies and expert volunteers working together. Anyone is free to inspect and modify the source code (a bit like the recipe) that makes it work. You don’t have to pay to use Linux, and you’re allowed to share it with other people, too.
You probably won’t be able to run the software you have on your other computers on your Raspberry Pi. It won’t run Windows or Mac software, and not all Linux software works on the Raspberry Pi. But a lot of Linux software that is compatible with the Raspberry Pi is available and is free of charge.
Figuring Out What You Can Do with a Raspberry Pi
The Raspberry Pi is a fully featured computer, and you can do almost anything with it that you can do with a desktop computer.
It has a graphical windows desktop to start and manage programs (see Chapter 4) as well as a shell for accepting text commands. (See Chapter 5.) You can use it for browsing the Internet (see Chapter 4), or for word processing and spreadsheets (see Chapter 6), or for editing photos. (See Chapter 7.) You can use it for playing back music or video (see Chapter 8) or for playing games. (See Chapter 19.) You can use the built-in software to write your own music, too. (See Chapter 14.) It’s the perfect tool for homework, but it’s also a useful computer for writing letters, managing your accounts, and paying bills online.
The Raspberry Pi is at its best, however, when it’s being used to learn how computers work, and how you can create your own programs or electronics projects using them. It comes with Scratch (see Chapter 9), which enables people of all ages to create their own animations and games while learning some of the core concepts of computer programming along the way.
It also comes with Python (see Chapter 11), a professional programming language used by YouTube, Google, and Industrial Light & Magic (the special effects gurus for the Star Wars films), among many others.
It has GPIO pins on it that you can use to connect up your own circuits to the Raspberry Pi, so you can use your Raspberry Pi to control other devices and to receive and interpret signals from them. In Part 5, we show you how to build some electronic projects controlled by the Raspberry Pi.
Getting Your Hands on a Raspberry Pi
One of the great things about the Raspberry Pi is that it's established a community of businesses that have created products for it, or have shared in its success by selling it. You can now buy the Raspberry Pi from a wide range of electronics companies for hobbyists. Global retailers include Pimoroni (www.pimoroni.com), The Pi Hut (https://thepihut.com), and Adafruit (www.adafruit.com). It's also available from the Raspberry Pi's distributors, RS Components (www.rs-components.com) and Element14 (www.element14.com).
You might also be able to buy it from your local computer or electronics store, although you'll probably find it's only available as part of a kit there. Shops often bundle the Raspberry Pi with other items you need to use it. It can be convenient to get everything at once, but it might not represent the cheapest way to get started.
Determining What Else You Need
The creators of Raspberry Pi have stripped costs to the bone to enable you to own a fully featured computer for less than $35, so you’ll need to scavenge or buy a few other bits and pieces in order to use your Pi. We say scavenge because the things you need are exactly the kind of things many people have lying around their house or garage already, or can easily pick up from friends or neighbors. In particular, if you’re using a Raspberry Pi as your second computer, you probably have most of the peripherals you need. That said, you might find they’re not fully compatible with the Raspberry Pi and you need to buy replacements to use with the Pi.
Here’s a checklist of what else you might need:
❯❯ Monitor: The Raspberry Pi has a high-definition video feed and uses an HDMI (high-definition multimedia interface) connection for it. If your monitor has an HDMI socket, you can connect the Raspberry Pi directly to it. If your monitor does not support HDMI, it probably has a DVI socket, and you can get a simple and cheap converter that enables you to connect an HDMI cable to it. Older VGA (video graphics array) monitors require a device to convert the HDMI signal into a VGA one. If you’re thinking of buying a converter, check online first to see whether it works with the Raspberry Pi. A lot of cheap cables are just cables, when what you need is a device that converts the signal from HDMI format to VGA, not one that just fits into the sockets on the screen and your Raspberry Pi. These converters can be quite expensive, so Gert van Loo has designed a device that uses the Raspberry Pi’s GPIO pins to connect to a VGA monitor. He’s published the design specs so that anyone can build one, and sell it if she wants to, too. Take a look at eBay if you need one, and you might well find what you need. For more information, check out www.raspberrypi.org/blog/gert-vga-adapter. (If your monitor is connected using a blue plug and the connector has three rows of five pins in it, it’s probably a VGA monitor.)
❯❯ TV: You can connect your Raspberry Pi to a high-definition TV using the HDMI socket and should experience a crisp picture. If you have an old television in the garage, you can also press it into service for your Raspberry Pi. The Pi can send a composite video signal, so it can use a TV as its display. When