Extreme NXT (eBook)

Michael Gasperi has been an expert in LEGO Mindstorms sensors since they were first introduced in 1998. His popular web site and contributing chapters to Extreme Mindstorms (Apress, 2000) have guided many people through the process of building their own extensions to the kit.

Contents at a Glance 5
Table of Contents 6
Foreword 12
About the Authors 14
Acknowledgments 16
Introduction 17
CHAPTER 1 In the Beginning 19
The RCX and the Robotics Invention System 20
The MINDSTORMS NXT 21
The Sensors 23
NXT Sensors 24
Touch 24
Light 25
Sound 27
Ultrasonic 30
Color 31
NXT Temperature 33
RCX Legacy Sensors 34
Touch 34
Light 35
Rotation 36
Temperature 37
The NXT Motor 37
CHAPTER 2 Extreme Software 39
NXT-G 39
My Blocks 41
Importing Blocks 50
Not eXactly C and Bricx Command Center 55
Other Alternative Languages 63
RobotC 63
LabVIEW 63
Java 63
CHAPTER 3 Making a Connection 64
NXT Ports 64
Sensor Input Pinout and Signal Description 64
Pin 1—White—AN 65
Pin 4—Green—4.3V Power 65
Pins 5 and 6—Yellow and Blue—DIGI0 and DIGI1 66
Motor Output Pinout 66
Pin 1 and 2—White and Black—M1 and M2 66
Pin 3—Red—GND 68
Pin 4—Green—4.3V POWER 68
Pin 5 and 6—Yellow and Blue—TACHO0 and TACHO1 68
Physically Connecting to the NXT 69
Buying Connectors 70
Making Your Own Connectors 71
Taped Telephone Plug Method 71
Modified Telephone Plug Method 73
Cut Cable Method 74
Screw Terminal for Passive Sensors 77
CHAPTER 4 Contact Sensors 79
Touching Wires 79
Electronic Surfboard 80
Construction 80
Programming 81
Switches 82
Parallel and Series 83
Antenna Sensor 83
Going Further 88
CHAPTER 5 Resistive Sensors 89
Analog-to-Digital Conversion 89
Ohmmeter 91
Ohmmeter Program 91
Measuring Salinity 92
Legacy Temperature Sensor 94
Thermistors 95
Reverse Engineering the NXT 97
Homebrew Legacy Temperature Sensor 99
NXT Digital Thermometer 101
Relative Humidity Sensor 103
Light Sensor 105
Building the Light Sensor 105
Comparison of LEGO and CdS Light Sensor 108
Theremin 110
Braitenberg Vehicle 2 112
Two-Switch Input 115
Building a Two-Switch Input 116
Programming a Two-Switch Input 117
CHAPTER 6 Potentiometer Sensors 119
Connecting to the Pot 119
Resistance Selection 120
Angle Sensor Construction 122
Pressure Sensor 126
Broom Balancer 128
Joysticks 131
Bottom Mounted Joystick 131
Top Mounted Joystick for a Robot Arm 132
CHAPTER 7 Voltage Sensors 135
Design of a –5V to +5V Sensor 135
Constructing the Voltage Sensor 137
NXT Battery Tester 139
A –15V to +15V Sensor 140
CHAPTER 8 4.3V Powered Sensors 143
Hall Effect Sensor 143
Hall Sensor Construction 144
Robot Mouse 146
Transistor Buffer 147
Infrared Rangefinder 150
Interface Construction 152
Operation of the Sensor 153
Wall Follower 153
Differential Light Sensor 154
Construction 155
Digital Sundial 156
Protecting the Transistor Buffer 160
CHAPTER 9 Two-Wire Powered Sensors 161
Signals 161
Power Supply 162
Programming 163
Half-Volt Sensor 164
Current Sensor 169
Electronic Whistler 170
Exposing the Filament 170
Whistler Construction 173
Pressure Sensor 174
CHAPTER 10 Light Sensor with LED Control 180
LED Control Circuit 180
Reflected Light Sensor 184
Transmissive Light Sensor 186
CHAPTER 11 LEGO Motor Interfaces 188
The Clapper 188
The Etch-A-NXT 190
Pneumatic Gripper 195
RCX 9V Motor 196
NXT Conversion Cable 198
Power Functions Motors 202
Power Functions Cabling 205
CHAPTER 12 Beyond LEGO Motors 210
The Motor Block 210
Output Control Program 211
Lamps 212
Muscle Wires 213
Electromagnets and Solenoids 216
Kinetic Sculpture 216
Relays 219
Doubling Outputs 221
Light Emitting Diodes 224
More Power 229
One MOSFET Amplifier 230
Bipolar MOSFET Amplifier 232
RC Servo Interface 237
CHAPTER 13 I2C Bus Communication 243
I2C Communications 243
PCF8574 244
Eight Outs 245
Magic Wand 249
Four Ins and Outs 252
Simon Game 256
Keypad Input 257
Relay Outputs 259
PCF8591 264
Four Analog Ins 266
2-D Light Sensor 270
RC Servo Controller 272
Color Sensor 275
Going Further 279
CHAPTER 14 Cool Combinations 280
Data Logging 280
NXT-to-NXT Bluetooth Remote Control 285
LEGO Train Station 287
Panoramic Camera 288
Graphics 292
NXT Pong Video Game 294
Remotely Guided Vehicle 296
Galvanic Skin Response Meter 301
APPENDIX A Construction Techniques 304
Solderless Breadboard 304
Building on the Breadboard 305
Printed Circuit Board 308
Soldering 311
Building a Printed Circuit Board 315
Prototype Board Kits 317
APPENDIX B References, Links, and Sources 322
General Interest 322
Chapter 1 323
Chapter 2 323
Chapter 3 323
Chapter 5 323
Chapter 6 324
Chapter 7 324
Chapter 8 324
Chapter 9 324
Chapter 10 324
Chapter 11 325
Chapter 12 325
Chapter 13 325
Chapter 14 326
Appendix A 326
APPENDIX C Code Listings 327
Chapter 13 327
Chapter 14 336
Index 338