The definitive guide to building Java robots

The Definitive Guide to

Building Java Robots

■■■

Scott Preston

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The Definitive Guide to Building Java Robots

Copyright © 2006 by Scott Preston

All rights reserved. No part of this work may be reproduced or transmitted in any form or by any means,

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Lead Editor: Steve Anglin

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Contents at a Glance

About the Author . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ix

About the Technical Reviewer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xi

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv

■CHAPTER 1 A Primer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

■CHAPTER 2 Serial Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

■CHAPTER 3 Motion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

■CHAPTER 4 Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

■CHAPTER 5 Speech . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

■CHAPTER 6 Vision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

■CHAPTER 7 Navigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221

■CHAPTER 8 Other Topics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289

■CHAPTER 9 Sample Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319

■APPENDIX A The Definitive Guide API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383

■APPENDIX B Microcontroller Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395

■APPENDIX C Robot Parts Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399

■INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403

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Contents

About the Author . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ix

About the Technical Reviewer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xi

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv

■CHAPTER 1 A Primer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1 Organizing Your Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.2 Java Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1.3 Organizing Your Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

■CHAPTER 2 Serial Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

2.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

2.1 A Simple Serial Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

2.2 Concurrent Serial Port Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

2.3 Creating a Web Serial Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

2.4 Serial Communications with a Microcontroller . . . . . . . . . . . . . . . . . . 37

2.5 Modeling a Microcontroller with Java . . . . . . . . . . . . . . . . . . . . . . . . 40

2.6 Bluetooth Serial Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

2.7 Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

■CHAPTER 3 Motion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

3.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

3.1 Servo Controllers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

3.2 Wheeled Motion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

3.3 Pan and Tilt Mechanisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

3.4 Advanced Servo Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

3.5 The Robot Arm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

3.6 Legged Robots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

3.7 Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

Contents

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■CHAPTER 4 Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

4.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

4.1 Orientation Sensors (Compass) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

4.2 Switch Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

4.3 Distance Sensors (IR and Sonar) . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

4.4 Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

■CHAPTER 5 Speech . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

5.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

5.1 Speech Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

5.2 Speech Recognition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

5.3 Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

■CHAPTER 6 Vision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

6.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

6.1 Image Capture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

6.2 Basic Image Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181

6.3 Color Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194

6.4 Advanced Image Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213

6.5 Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219

■CHAPTER 7 Navigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221

7.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221

7.1 Navigation Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236

7.2 Localization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248

7.3 Obstacle Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259

7.4 Indoor Navigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266

7.5 Outdoor Navigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280

7.6 Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287

■CHAPTER 8 Other Topics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289

8.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289

8.1 Running Your Java Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289

8.2 Scheduling Your Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291

8.3 Ant Building and More . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295

8.4 Database Access with JDBC and MySQL . . . . . . . . . . . . . . . . . . . . 299

8.5 Using and Installing Tomcat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310

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8.6 Java Scripting Languages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314

8.7 Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 316

■CHAPTER 9 Sample Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319

9.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319

9.1 Miscellaneous Utilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320

9.2 Webcam Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 326

9.3 Remote Control Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342

9.4 Diagnostic Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362

9.5 Navigation Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373

9.6 Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382

■APPENDIX A The Definitive Guide API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383

■APPENDIX B Microcontroller Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395

■APPENDIX C Robot Parts Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399

■INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403

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About the Author

■SCOTT PRESTON works as a Java architect in Columbus, Ohio, where he

resides with his wife, Emily, and dog, Castle. Scott has over 20 years of soft￾ware and electrical experience, including positions with the U.S. Navy, Bank

One, CompuServe, UUNET, and Covansys Inc., in addition to running his

own robotics company, Preston Research LLC. Scott also gives lectures

about robotics at COSI (Center of Science and Industry) and manufactures

small Java-enabled robots called CubeBots®. Scott is a member of the Java

Community Process and an alumnus of The Ohio State University.

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About the Technical Reviewer

■SIMON RITTER is a Java technology evangelist at Sun Microsystems. Simon has been in the IT

business since 1984 and holds a bachelor of science degree in physics from Brunel University in

the UK. Originally working in the area of UNIX development for AT&T UNIX System Labs and

then Novell, Simon moved to Sun in 1996. At that time, he began working with Java technology

and has since divided his time between Java technology development and consultancy. He now

specializes in emerging technologies, including grid computing, RFID, robotics, and smart

sensor networks. Simon and his performing Java-powered LEGO robots have appeared before

audiences worldwide.

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Acknowledgments

I would like to especially thank my loving wife, Emily, for putting up with me while I wrote this

book and for all the hours I spent at the PC and downstairs with the robots when I could have

been spending it with her.

Second, I would like to thank Steve Anglin, Simon Ritter, Sofia Marchant, Michael McGee,

and Katie Stence for helping me write this book, and to readers and others at Apress who have

been a joy to work with.

Third, I would like to thank Ken Gracey from Parallax, Inc., and Jim Frye from Lynxmotion,

Inc., for supplying me with various parts, components, and advice during the writing of this book.

Fourth, I would like to thank my mother for passing on her common sense and buying me

an Atari 400 in 1980, and my father for passing on his engineering smarts and helping me build

the original Feynman in 2002.

Fifth, I would like to thank my in-laws, Frikkie and Karen Roets, for their hospitality last

Christmas (and always), and for the use of their office to contact Apress about writing this book.

Sixth, I would like to thank my high-school science teacher, Jan Greissinger, for inspiring

me to love science as much as I do today, and also Guy Kawasaki for his books and e-mails,

which inspired me to write this book.

Finally, I could not end without mentioning my friends Harry and Crissy, Ron and Sophia,

Mark and Maria, Bard and Ann, Mark and Tracy, and John and Kristi. I was meaning to spend

more time with you this summer, and even come out and visit those who are a little more than

a drive away. Plan on that in 2006.

Scott Preston

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