Exploring Arduino

Tools and Techniques for Engineering Wizardry

Jeremy Blum

• Publisher: Wiley
• Year: 2019
• ISBN:
  9781119405306
• Edition: 2
• Topic: Ciencia de la computación
• Subtopic: Hardware

The bestselling beginner Arduino guide, updated with new projects!

Exploring Arduino makes electrical engineering and embedded software accessible. Learn step by step everything you need to know about electrical engineering, programming, and human-computer interaction through a series of increasingly complex projects. Arduino guru Jeremy Blum walks you through each build, providing code snippets and schematics that will remain useful for future projects. Projects are accompanied by downloadable source code, tips and tricks, and video tutorials to help you master Arduino. You'll gain the skills you need to develop your own microcontroller projects!

This new 2nd edition has been updated to cover the rapidly-expanding Arduino ecosystem, and includes new full-color graphics for easier reference. Servo motors and stepper motors are covered in richer detail, and you'll find more excerpts about technical details behind the topics covered in the book. Wireless connectivity and the Internet-of-Things are now more prominently featured in the advanced projects to reflect Arduino's growing capabilities. You'll learn how Arduino compares to its competition, and how to determine which board is right for your project. If you're ready to start creating, this book is your ultimate guide!

• Get up to date on the evolving Arduino hardware, software, and capabilities
• Build projects that interface with other devices—wirelessly!
• Learn the basics of electrical engineering and programming
• Access downloadable materials and source code for every project

Whether you're a first-timer just starting out in electronics, or a pro looking to mock-up more complex builds, Arduino is a fantastic tool for building a variety of devices. This book offers a comprehensive tour of the hardware itself, plus in-depth introduction to the various peripherals, tools, and techniques used to turn your little Arduino device into something useful, artistic, and educational. Exploring Arduino is your roadmap to adventure—start your journey today!

II
Interfacing with Your Environment

• Chapter 4: Using Transistors and Driving DC Motors
• Chapter 5: Driving Stepper and Servo Motors
• Chapter 6: Making Sounds and Music
• Chapter 7: USB Serial Communication
• Chapter 8: Emulating USB Devices
• Chapter 9: Shift Registers

4
Using Transistors and Driving DC Motors

Parts You'll Need for This Chapter:

• Arduino Uno or Adafruit METRO 328
• USB cable (Type A to B for Uno, Type A to Micro-B for METRO)
• Half-size breadboard
• Assorted jumper wires
• 1kΩ resistor
• 10kΩ resistors (×2)
• 10kΩ trim potentiometer
• Photoresistors (×2)
• 9V battery
• 9V battery clip
• L7805CV 5V voltage regulator
• 10μF 50V electrolytic capacitors (×2)
• 0.1μF ceramic capacitor
• 1N4001 diode
• PN2222 NPN bipolar junction transistor (BJT)
• Roving robot chassis kit with wheels and DC motors
• 9V DC motor
• TI L293D dual H-bridge motor driver
  • CODE AND DIGITAL CONTENT FOR THIS CHAPTER
  • Code downloads, videos, and other digital content for this chapter can be found at:
  • exploringarduino.com/content2/ch4
  • Code for this chapter can also be obtained from the Downloads tab on this book's Wiley web page:
  • wiley.com/go/exploringarduino2e

You're now a master of observing information from the world around you. But how can you control that world? Blinking LEDs and automatically adjusting nightlights are a good start, but you can do so much more. Using assorted types of motors and actuators, and with the help of transistors, you can use your Arduino to generate physical action in the real world. By pairing motors with your Arduino, you can drive robots, build mechanical arms, add an additional degree of freedom to distance sensors, and much more.

In this chapter, you will learn how to control inductive loads like direct current (DC) motors, how to use transistors to switch high-current devices, and how to add integrated circuits (ICs) to your projects. At the end of this chapter, you will build a light-controlled car that you can control using only a flashlight!

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NOTE

If you want to learn all about motors and transistors, you can watch a video on this topic on this chapter's content web page: exploringarduino.com/content2/ch4.

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WARNING

In this chapter, you use a 9V battery so that you can run motors that require more power than the Arduino can provide. These voltages are still not high enough to pose a danger to you, but if hooked up improperly, these batteries can damage your electronics. As you make your way through the exercises in this chapter, follow the diagrams and instructions carefully. Avoid short circuits (connecting power directly to ground), and when you are sharing the ground line between power supplies, don't try to connect two separate voltage sources to each other. For example, don't try to hook both the 9V supply and the Arduino's 5V supply into the same supply row on the breadboard. Doing so could damage the 5V regulator on your Arduino, damaged the Arduino's microcontroller.

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Driving DC Motors

DC motors, which you can find in numerous devices around your home, rotate continuously when a DC voltage is applied across them. These motors are commonly used as the driving motors in radio control (RC) cars, in power drills and saws, and as the motors that make the discs spin in DVD players. DC motors are great because they come in a huge array of sizes and are generally very cheap. By adjusting the voltage you apply to them, you can change their rotation speed. Using a gearbox, you can trade their speed for torque. By reversing the direction of the voltage applied to them, you can change their direction of rotation as well. This is generally done using an H-bridge, which you will learn about later in this chapter.

Brushed DC motors, such as the ones you are using for this chapter, employ stationary magnets (the stator) and a spinning coil (the rotor). Electricity is transferred to the coil using “brushes,” hence the name brushed DC motors. Unlike brushless DC motors (such as the stepper motors that you'll explore in the next chapter), brushed DC motors are cheap and offer easier speed control. However, brushed DC motors do not last as long because the brushes can wear out over time.

Some larger devices that rely on brushed motors, like corded power tools, have replaceable carbon brushes. Brushed DC motors work through an inductive force. When current passes through the spinning coil, it generates a magnetic field that is either attracted to or repelled ...