About the Author . xiii About the Technical Reviewers . xv Acknowledgments . xvii Introduction . xix ■CHAPTER 1 Tomb, Trap, and Trigger . 1 ■CHAPTER 2 ExploroBot—Planning and Design 7 ■CHAPTER 3 ExploroBot—Build It 17 ■CHAPTER 4 ExploroBot—Program It . 41 ■CHAPTER 5 String, Pebbles, and Gravity . 57 ■CHAPTER 6 StringBot—Planning and Design 63 ■CHAPTER 7 StringBot—Build It 73 ■CHAPTER 8 StringBot—Program It 91 ■CHAPTER 9 Scroll, Key, and Camera 107 ■CHAPTER 10 SnapShotBot—Planning and Design 115 ■CHAPTER 11 SnapShotBot—Build It . 127 ■CHAPTER 12 SnapShotBot—Program It 149 ■CHAPTER 13 Get In, Grab It, Get Out 165 ■CHAPTER 14 GrabberBot—Planning and Design . 171 ■CHAPTER 15 GrabberBot—Build It . 179 ■CHAPTER 16 GrabberBot—Program It . 203 ■CHAPTER 17 Bravery, Wisdom, and Honor 217 ■CHAPTER 18 PushBot—Planning and Design 223 ■CHAPTER 19 PushBot—Build It 231 ■CHAPTER 20 PushBot—Program It . 255 ■CHAPTER 21 Discovery, Secret, and Home . 281 ■APPENDIX A Online Reference and Support 285 ■APPENDIX B Building Instructions for Bots . 287 ■APPENDIX C NXTLOG 291 ■APPENDIX D HiTechnic NXT Compass Sensor 295 ■INDEX . 305