Exploring Raspberry Pi

Interfacing to the Real World with Embedded Linux

Derek Molloy

• Publisher: Wiley
• Year: 2016
• ISBN:
  9781119188698
• Edition: 1
• Topic: Informatica
• Subtopic: Hardware

Expand Raspberry Pi capabilities with fundamental engineering principles

Exploring Raspberry Pi is the innovators guide to bringing Raspberry Pi to life. This book favors engineering principles over a 'recipe' approach to give you the skills you need to design and build your own projects. You'll understand the fundamental principles in a way that transfers to any type of electronics, electronic modules, or external peripherals, using a "learning by doing" approach that caters to both beginners and experts. The book begins with basic Linux and programming skills, and helps you stock your inventory with common parts and supplies. Next, you'll learn how to make parts work together to achieve the goals of your project, no matter what type of components you use. The companion website provides a full repository that structures all of the code and scripts, along with links to video tutorials and supplementary content that takes you deeper into your project.

The Raspberry Pi's most famous feature is its adaptability. It can be used for thousands of electronic applications, and using the Linux OS expands the functionality even more. This book helps you get the most from your Raspberry Pi, but it also gives you the fundamental engineering skills you need to incorporate any electronics into any project.

• Develop the Linux and programming skills you need to build basic applications
• Build your inventory of parts so you can always "make it work"
• Understand interfacing, controlling, and communicating with almost any component
• Explore advanced applications with video, audio, real-world interactions, and more

Be free to adapt and create with Exploring Raspberry Pi.

Part I
Raspberry Pi Basics

In This Part

1. Chapter 1: Raspberry Pi Hardware
2. Chapter 2: Raspberry Pi Software
3. Chapter 3: Exploring Embedded Linux Systems
4. Chapter 4: Interfacing Electronics
5. Chapter 5: Programming on the Raspberry Pi

Chapter 1
Raspberry Pi Hardware

In this chapter, you are introduced to the Raspberry Pi (RPi) platform hardware. The chapter focuses on recently released Raspberry Pi models and describes the various subsystems and physical inputs/outputs of the boards. In addition, the chapter lists accessories that can prove helpful in developing your own Raspberry Pi–based projects. By the end of this chapter, you should have an appreciation of the power and complexity of this physical-computing platform. You should also be aware of the first steps to take to protect your board from physical damage.

Introduction to the Platform

The RPi models are capable general-purpose computing devices, and for that reason they have found favor for introducing learners to general computing and computer programming. The RPi models, some of which are illustrated in Figure 1.1, are also capable physical computing devices that can be used for embedded systems applications—and for Internet-attached embedded applications in particular.

Figure 1.1 Raspberry Pi platform board examples (to relative scale)

Some general characteristics of RPi devices include the following:

• They are low cost, available for as little as $5–$35.
• They are powerful computing devices. For example, the RPi 3 contains a 1.2 GHz ARM Cortex-A53 processor that can perform more than 700 million Whetstone instructions per second (MWIPS).¹
• They are available in a range of models that are suitable for different applications (e.g., the larger-format RPi 3 for prototyping and the tiny-format RPi Zero or Compute Module for deployment).
• They support many standard interfaces for electronic devices.
• They use little power, running at between approximately 0.5 W (RPi Zero when idle) and approximately 5.5 W (RPi 3 under load).
• They are expandable through the use of Hardware Attached on Top (HAT) daughter boards and USB devices.
• They are supported by a huge community of innovators and enthusiasts, who generously give of their time to help the RPi Foundation with their educational mission.

The RPi platform can run the Linux operating system, which means that you can use many open source software libraries and applications directly with it. Open source software driver availability also enables you to interface devices such as USB cameras, keyboards, and Wi-Fi adapters with your project, without having to source proprietary alternatives. Therefore, you have access to comprehensive libraries of code that have been built by a talented open source community; however, it is important to remember that the code typically comes without any type of warranty or guarantee. If there are problems, you have to rely on the good nature of the community to resolve them. Of course, you could also fix the problems yourself and make the solutions publicly available.

One impressive feature of recent RPi models is that their functionality can be extended with daughter boards, called HATs (Hardware Attached on Top), that connect to the GPIO header (the 40-pin double-pin connector row on the boards in Figure 1.1). You can design your own HATs and attach them securely to your RPi using this header. In addition, many HATs are available for purchase that can be used to expand the functionality of your RPi platform. Some examples of these are described toward the end of this chapter.

Who Should Use the RPi

Anybody who wants to transform an engineering concept into a real interactive electronics project, prototype, or work of art should consider using the RPi. That said, integrating high-level software and low-level electronics is not an easy task. However, the difficulty involved in an implementation depends on the level of sophistication that the project demands. The RPi community is working hard to ensure that the platform is accessible by everyone who is interested in integrating it into their projects, whether they are students, makers, artists, or hobbyists. For example, the availability of the Scratch visual programming tool on the RPi (tiny.cc/erpi101) is an excellent way to engage children with both computer programming and the RPi.

For more advanced users with electronics or computing knowledge, the RPi platform enables additional development and customization to meet specific project needs. Again, such customization is not trivial: You may be an electronics expert, but high-level software programming and/or the Linux operating system might cause you difficulty. Or you may be a programming guru but you have never wired an LED! This book aims to cater to all types of users who are interested in interfacing with the RPi, pr...