Arduino Sketches
Tools and Techniques for Programming Wizardry

Arduino Sketches is a practical guide to programming the increasingly popular microcontroller that brings gadgets to life. Accessible to tech-lovers at any level, this book provides expert instruction on Arduino programming and hands-on practice to test your skills. You'll find coverage of the various Arduino boards, detailed explanations of each standard library, and guidance on creating libraries from scratch ? plus practical examples that demonstrate the everyday use of the skills you're learning. Work on increasingly advanced programming projects, and gain more control as you learn about hardware-specific libraries and how to build your own. Take full advantage of the Arduino API, and learn the tips and tricks that will broaden your skillset.

The Arduino development board comes with an embedded processor and sockets that allow you to quickly attach peripherals without tools or solders. It's easy to build, easy to program, and requires no specialized hardware. For the hobbyist, it's a dream come true ? especially as the popularity of this open-source project inspires even the major tech companies to develop compatible products. Arduino Sketches is a practical, comprehensive guide to getting the most out of your Arduino setup. You'll learn to:

• Communicate through Ethernet, WiFi, USB, Firmata, and Xbee
• Find, import, and update user libraries, and learn to create your own
• Master the Arduino Due, Esplora, Yun, and Robot boards for enhanced communication, signal-sending, and peripherals
• Play audio files, send keystrokes to a computer, control LED and cursor movement, and more

This book presents the Arduino fundamentals in a way that helps you apply future additions to the Arduino language, providing a great foundation in this rapidly-growing project. If you're looking to explore Arduino programming, Arduino Sketches is the toolbox you need to get started.

Introduction xxix

Part I Introduction to Arduino 1

Chapter 1 Introduction to Arduino 3

Atmel AVR 5

The Arduino Project 7

The ATmega Series 8

The ATmega Series 8

The ATtiny Series 8

Other Series 9

The Different Arduinos 9

Arduino Uno 10

Arduino Leonardo 10

Arduino Ethernet 11

Arduino Mega 2560 11

Arduino Mini 13

Arduino Micro 13

Arduino Due 13

LilyPad Arduino 14

Arduino Pro 16

Arduino Robot 16

Arduino Esplora 18

Arduino Yún 18

Arduino Tre 19

Arduino Zero 19

Your Own Arduino? 20

Shields 20

What Is a Shield? 20

The Different Shields 21

Arduino Motor Shield 21

Arduino Wireless SD Shield 21

Arduino Ethernet Shield 21

Arduino WiFi Shield 22

Arduino GSM Shield 22

Your Own Shield 22

What Can You Do with an Arduino? 22

What You Will Need for This Book 23

Summary 24

Chapter 2 Programming for the Arduino 25

Installing Your Environment 26

Downloading the Software 27

Running the Software 28

Using Your Own IDE 29

Your First Program 29

Understanding Your First Sketch 33

Programming Basics 36

Variables and Data Types 36

Control Structures 38

if Statement 38

switch Case 39

while Loop 40

for Loop 41

Functions 42

Libraries 42

Summary 42

Chapter 3 Electronics Basics 45

Electronics 101 46

Voltage, Amperage, and Resistance 46

Voltage 47

Amperage 48

Resistance 48

Ohm’s Law 49

The Basic Components 49

Resistors 50

Different Resistor Values 50

Identifying Resistor Values 50

Using Resistors 52

Capacitors 53

Using Capacitors 54

Diodes 54

Different Types of Diodes 54

Using Diodes 55

Light-Emitting Diodes 55

Using LEDs 55

Transistors 56

Using Transistors 56

Breadboards 56

Inputs and Outputs 57

Connecting a Light-Emitting Diode 58

Calculation 58

Software 59

Hardware 60

What Now? 61

Summary 61

Part II Standard Libraries 63

Chapter 4 The Arduino Language 65

I/O Functions 65

Digital I/O 65

pinMode() 66

digitalRead() 66

digitalWrite() 67

Analog I/O 67

analogRead() 68

analogWrite() 68

Generating Audio Tones 69

tone() 69

noTone() 69

Reading Pulses 69

pulseIn() 70

Time Functions 70

delay() 70

delayMicroseconds() 71

millis() 71

micros() 71

Mathematical Functions 72

min() 72

max() 72

constrain() 73

abs() 73

map() 73

pow() 74

sqrt() 74

random() 74

Trigonometry 75

sin() 76

cos() 76

tan() 76

Constants 76

Interrupts 76

attachInterrupt() 77

detachInterrupt() 78

noInterrupts() 78

interrupts() 78

Summary 79

Chapter 5 Serial Communication 81

Introducing Serial Communication 82

UART Communications 84

Baud Rate 84

Data Bits 85

Parity 85

Stop Bits 86

Debugging and Output 86

Starting a Serial Connection 87

Writing Data 88

Sending Text 88

Sending Data 90

Reading Data 91

Starting Communications 91

Is Data Waiting? 91

Reading a Byte 92

Reading Multiple Bytes 92

Taking a Peek 93

Parsing Data 93

Cleaning Up 94

Example Program 95

SoftwareSerial 98

Summary 99

Chapter 6 EEPROM 101

Introducing EEPROM 101

The Different Memories on Arduino 103

The EEPROM Library 104

Reading and Writing Bytes 104

Reading and Writing Bits 105

Reading and Writing Strings 107

Reading and Writing Other Values 108

Example Program 110

Preparing EEPROM Storage 113

Adding Nonvolatile Memory 114

Summary 115

Chapter 7 SPI 117

Introducting SPI 118

SPI Bus 118

Comparison to RS-232 119

Confi guration 119

Communications 120

Arduino SPI 120

SPI Library 121

SPI on the Arduino Due 123

Example Program 125

Hardware 126

Sketch 128

Exercises 131

Summary 132

Chapter 8 Wire 133

Introducing Wire 134

Connecting I2C 135

I2C Protocol 135

Address 136

Communication 137

Communicating 138

Master Communications 139

Sending Information 139

Requesting Information 140

Slave Communications 141

Receiving Information 141

Sending Information 142

Example Program 142

Exercises 146

Traps and Pitfalls 147

Voltage Difference 147

Bus Speed 147

Shields with I2C 148

Summary 148

Chapter 9 Ethernet 149

Introduction 149

Ethernet 150

Ethernet Cables 151

Switches and Hubs 151

PoE 152

TCP/IP 152

MAC Address 153

IP Address 153

DNS 153

Port 153

Ethernet on Arduino 154

Importing the Ethernet Library 154

Starting Ethernet 155

Arduino as a Client 157

Sending and Receiving Data 158

Connecting to a Web Server 159

Example Program 161

Arduino as a Server 163

Serving Web Pages 164

Example Program 165

Sketch 165

Summary 167

Chapter 10 WiFi 169

Introduction 170

The WiFi Protocol 171

Topology 171

Network Parameters 172

Channels 172

Encryption 172

SSID 173

RSSI 173

Arduino WiFi 173

Importing the Library 174

Initialization 174

Status 175

Scanning Networks 176

Connecting and Configuring 177

Wireless Client 178

Wireless Server 179

Example Application 179

Hardware 181

Sketch 182

Exercises 189

Summary 190

Chapter 11 LiquidCrystal 191

Introduction 192

LiquidCrystal Library 194

Writing Text 195

Cursor Commands 196

Text Orientation 197

Scrolling 197

Custom Text 198

Example Program 199

Hardware 200

Software 201

Exercises 205

Summary 205

Chapter 12 SD 207

Introduction 208

SD Cards 211

Capacity 212

Speed 213

Using SD Cards with Arduino 213

Accepted SD Cards 214

Limitations 214

The SD Library 215

Importing the Library 215

Connecting a Card 215

Opening and Closing Files 216

Reading and Writing Files 217

Reading Files 217

Writing Files 218

Folder Operations 218

Card Operations 219

Advanced Usage 220

Example Program and Sketch 220

Summary 224

Chapter 13 TFT 225

Introduction 226

Technologies 227

TFT Library 228

Initialization 228

Screen Preparation 229

Text Operations 230

Basic Graphics 231

Coloring 232

Graphic Images 232

Example Application 233

Hardware 234

Sketch 234

Exercises 239

Summary 239

Chapter 14 Servo 241

Introduction to Servo Motors 242

Controlling Servo Motors 243

Connecting a Servo Motor 243

Moving Servo Motors 244

Disconnecting 245

Precision and Safety 246

Example Application 246

Schematic 248

Sketch 249

Exercises 250

Summary 251

Chapter 15 Stepper 253

Introducing Motors 254

Controlling a Stepper Motor 254

Hardware 255

Unipolar Versus Bipolar Stepper Motors 255

The Stepper Library 256

Example Project 257

Hardware 257

Sketch 258

Summary 260

Chapter 16 Firmata 261

Introducing Firmata 262

Firmata Library 262

Sending Messages 263

Receiving Messages 263

Callbacks 264

SysEx 266

Example Program 268

Summary 269

Chapter 17 GSM 271

Introducing GSM 272

Mobile Data Network 272

GSM 273

GPRS 274

EDGE 274

3 G 274

4 G and the Future 275

Modems 275

Arduino and GSM 276

Arduino GSM Library 276

GSM Class 278

SMS Class 279

VoiceCall Class 281

GPRS 282

Modem 284

Example Application 285

Summary 288

Part III Device-Specific Libraries 289

Chapter 18 Audio 291

Introducing Audio 292

Digital Sound Files 292

Music on the Arduino 294

Arduino Due 294

Digital to Analog Converters 295

Digital Audio to Analog 295

Creating Digital Audio 296

Storing Digital Audio 296

Playing Digital Audio 296

Example Program 298

Hardware 298

Sketch 300

Exercise 303

Summary 304

Chapter 19 Scheduler 305

Introducing Scheduling 306

Arduino Multitasking 307

Scheduler 308

Cooperative Multitasking 309

Noncooperative Functions 311

Example Program 313

Hardware 314

Sketch 316

Exercises 319

Summary 319

Chapter 20 USBHost 321

Introducing USBHost 322

USB Protocol 323

USB Devices 324

Keyboards 324

Mice 325

Hubs 325

Arduino Due 325

USBHost Library 327

Keyboards 327

Mice 329

Example Program 330

Hardware 331

Source Code 332

Summary 334

Chapter 21 Esplora 335

Introducing Esplora 336

The Arduino Esplora Library 337

RGB LED 337

Sensors 338

Buttons 339

Buzzer 340

TinkerKit 341

LCD Module 342

Example Program and Exercises 342

Summary 344

Chapter 22 Robot 345

Introducing Robot Library 346

Arduino Robot 348

Robot Library 349

Control Board 350

Robotic Controls 350

Sensor Reading 351

Personalizing Your Robot 353

LCD Screen 354

Music 356

Motor Board 357

Example Program and Exercises 358

Summary 360

Chapter 23 Bridge 361

Introducing Bridge Library 362

Bridge 363

Process 364

FileIO 366

YunServer 367

YunClient 368

Example Application 369

Hardware 369

Sketch 370

Exercises 373

Summary 373

Part IV User Libraries and Shields 375

Chapter 24 Importing Third-Party Libraries 377

Libraries 378

Finding Libraries 378

Importing a Library 379

Using an External Library 381

Example Application 384

Exercises 389

Summary 389

Chapter 25 Creating Your Own Shield 391

Creating a Shield 391

The Idea 392

The Required Hardware 392

The Required Software 393

Your First Shield 394

Step 1: The Breadboard 395

Step 2: The Schematic 398

Step 3: The PCB 402

Summary 404

Chapter 26 Creating Your Own Library 405

Libraries 405

Library Basics 406

Simple Libraries 406

Advanced Libraries 410

Adding Comments 413

Adding Examples 415

Read Me 415

Coding Style 416

Use CamelCase 416

Use English Words 416

Don’t Use External Libraries 417

Use Standard Names 417

Distributing Your Library 417

Closed Source Libraries 417

Example Library 418

The Library 418

Examples 424

README 427

Finishing Touches 428

Summary 428

Index 429

James A. Langbridge is a software consultant specializing in embedded systems and code optimization including bootl oader code, system initialization, and code optimization. He has a history in in robotics, mobile phones, and seismic detection systems, with over 10 years in the aviation, defense, industry and telecom sectors, and served as an R&D consultant for ST Microelectronics and Amtel. James has also been called upon to train development teams and coach junior developers to their maximum potential.