Building Robots with LEGO Mindstorms NXT [Minkštas viršelis]

Foreword		xxiii
Preface		xxv
Understanding LEGO® Geometry		1	(12)
Introduction		2	(1)
Expressing Sizes and Units		2	(2)
Squaring the LEGO World: Vertical Bracing		4	(2)
Tilting the LEGO World: Diagonal Bracing		6	(3)
Technic Liftarms: Angles Built In		9	(2)
Summary		11	(2)
Playing with Gears		13	(28)
Introduction		14	(1)
Counting Teeth		14	(1)
Gearing Up and Down		15	(2)
Riding That Train: The Geartrain		17	(2)
Worming Your Way: The Worm Gear		19	(1)
Limiting Strength with the Clutch Gear		20	(3)
Placing and Fitting Gears		23	(7)
Using Pulleys, Belts, and Chains		30	(5)
Pulleys and Belts		31	(2)
Chains		33	(2)
Making a Difference: The Differential		35	(3)
Summary		38	(3)
Controlling Motors		41	(20)
Introduction		42	(1)
Pacing, Trotting, and Galloping		43	(5)
Internals of NXT Servo Motor		47	(1)
Mounting Motors		48	(3)
Wiring Motors		51	(3)
Using Power Function Motors with the NXT		52	(2)
Controlling Power		54	(3)
Detecting Motor Overload		55	(1)
Braking the Motor		56	(1)
Coupling Motors		57	(2)
Summary		59	(2)
Reading Sensors		61	(38)
Introduction		62	(1)
Digital Sensor Ports with the I2C (Inter-Integrated Circuit) Interface		62	(3)
The Touch Sensor		65	(6)
The Light Sensor		71	(2)
Measuring Reflected Light		73	(6)
Line Following		74	(3)
The Ultrasonic Sensor		77	(2)
Proximity Detection		79	(4)
The Servo Motor Encoder (Rotation Sensor)		79	(4)
Sensor Tips and Tricks		83	(5)
Emulating a Rotation Sensor		84	(2)
Connecting Multiple Sensors to the Same Port---Multiplexing		86	(2)
Other Sensors		88	(10)
The Passive Infrared Sensor		89	(1)
The Pressure Sensor		90	(2)
The Acceleration Sensor		92	(2)
The Compass Sensor		94	(1)
The NXT-to-RCX Communication Bridge		95	(1)
The Color Sensor		96	(2)
Summary		98	(1)
What's New with the NXT?		99	(14)
Introduction		100	(1)
Notable Enhancements		100	(1)
Studless Construction		100	(1)
Electrical Connectors		100	(1)
Rechargeable Battery Pack		100	(1)
Flash Memory		101	(1)
Multiple Types of Sensors		101	(1)
The NXT File System		101	(2)
File-Handling Functions		102	(1)
Using File Space Efficiently		103	(1)
The LCD Screen		103	(2)
Games		104	(1)
Digital Interfaces and Bluetooth		105	(4)
Bluetooth Communication		106	(1)
A Surveillance Robot Using NXT and Bluetooth		106	(1)
A Bluetooth-Based Remote Controller		107	(1)
Spatial Motion Controllers		108	(1)
I2C for Spatial Motion Controllers		109	(1)
Future Possibilities		109	(2)
An NXT Robot Controlled from a Web Server		109	(1)
NXT Puppet Show		110	(1)
GPS and the NXT		110	(1)
Summary		111	(2)
Building Strategies		113	(20)
Introduction		114	(1)
Studless Building Techniques		114	(4)
Maximizing Modularity		118	(3)
Loading the Structure		121	(3)
Putting It All Together: Chassis, Modularity, and Load		124	(5)
Hybrid Robots: Using Studless and Studded LEGO Pieces		129	(2)
Summary		131	(2)
Programming the NXT		133	(26)
Introduction		134	(1)
What Is the NXT Programmable Brick?		134	(3)
Mindstorms: A Family of Programmable Bricks		136	(1)
Introduction to Programming the NXT Brick		137	(4)
How Does a Program Run?		138	(1)
Using NXT-G		139	(2)
Using RobotC		141	(1)
Using Other Programming Languages		142	(3)
Using NBC/NXC		143	(1)
Using pbLUA		144	(1)
Using LeJOS NXJ		144	(1)
Using Other Programming Tools and Environments		144	(1)
Code Samples		145	(12)
Code Sample: A Simple Clock		145	(6)
Code Sample: Following a Line		151	(6)
Running Independent Tasks		157	(1)
Summary		158	(1)
Playing Sounds and Music		159	(10)
Introduction		160	(1)
Communicating through Tones		160	(1)
Playing Music		161	(2)
Converting Sound and Music Files		163	(4)
MIDI and MIDIBatch		163	(2)
WAV2RSO		165	(1)
The Sound Sensor		166	(1)
Summary		167	(2)
Becoming Mobile		169	(24)
Introduction		170	(1)
Building the Simple Differential Drive		170	(10)
Keeping a Straight Path		172	(1)
Using Servo Motor Encoders to Go Straight		172	(1)
Using Gears to Go Straight		173	(4)
Using Casters to Go Straight		177	(3)
Building a Skid-Steer Drive		180	(3)
Building a Steering Drive		183	(4)
Building a Synchro Drive		187	(4)
Other Configurations		191	(1)
Summary		192	(1)
Getting Pumped: Pneumatics		193	(18)
Introduction		194	(1)
Recalling Some Basic Science		194	(1)
Pumps and Cylinders		195	(5)
Controlling the Airflow		200	(2)
Building Air Compressors		202	(4)
Building a Pneumatic Engine		206	(4)
Summary		210	(1)
Finding and Grabbing Objects		211	(18)
Introduction		212	(1)
Operating Hands and Grabbers		212	(10)
Using Pneumatics to Drive Your Grabber		218	(4)
Finding Objects		222	(3)
Positioning the Grabber		225	(1)
Distinguishing Objects and Obstacles		225	(3)
Summary		228	(1)
Doing the Math		229	(20)
Introduction		230	(1)
Multiplying and Dividing		231	(2)
Averaging Data		233	(7)
Simple Averages		233	(4)
Weighted Averages		237	(3)
Using Interpolation		240	(3)
Understanding Hysteresis		243	(2)
Higher Math		245	(3)
Summary		248	(1)
Knowing Where You Are		249	(16)
Introduction		250	(1)
Choosing Internal or External Guidance		250	(1)
Looking for Landmarks: Absolute Positioning		251	(8)
Following the Beam		255	(4)
Map Matching Using Ultrasonic Sensor		259	(1)
Combining Compass Sensor to Increase Precision		260	(1)
Measuring Movement: Relative Positioning		260	(2)
Measuring Movement: Acceleration Sensor		262	(1)
Summary		263	(2)
Classic Projects		265	(14)
Introduction		266	(1)
Exploring Your Room		266	(5)
Detecting Edges		269	(1)
Variations on Obstacle Detection		270	(1)
Following a Line		271	(7)
Further Optimization of Line Following		277	(1)
Summary		278	(1)
Building Robots That Walk		279	(26)
Introduction		280	(1)
The Theory behind Walking		280	(6)
Building Legs		286	(2)
Building a Four-Legged Robot		288	(3)
Building a Six-Legged Steering Robot		291	(5)
Designing Bipeds		296	(7)
Interlacing Legs		297	(3)
COG Shifting		300	(2)
Making Bipeds Turn		302	(1)
Summary		303	(2)
Robotic Animals		305	(22)
Introduction		306	(1)
Creating a Monkey		306	(8)
Step 1: Center Motor Assembly		307	(1)
Step 2: Shoulder Assembly		308	(1)
Step 3: Shoulder/NXT Brick Bracing		309	(1)
Step 4: Shoulder-to-Arms Support		310	(1)
Step 5: Arm Motors		311	(1)
Step 6: Monkey Fingers		312	(1)
Step 7: NXT Brick Backbracing and Ultrasonic Sensor		313	(1)
The Final Step: Wiring Your Monkey		314	(1)
Programming Your Monkey		314	(2)
Creating a Mouse		316	(8)
Step 1: Mouse Frame and Motor Assembly		316	(2)
Step 2: Castor Bottom		318	(1)
Step 3: Tail Assembly		318	(1)
Step 4: The Mouse Head Frame		319	(1)
Step 5: Motorized Mouse Head Assembly		320	(1)
Step 6: Mounting the Mouse Head to the Body		321	(1)
Step 7: A Programming Example		322	(2)
Creating Other Animals		324	(1)
Summary		325	(2)
Solving a Maze		327	(22)
Introduction		328	(1)
Finding the Way Out		328	(5)
Using the Left Side-Right Side Strategy		330	(2)
Applying Other Strategies		332	(1)
Building a Maze Runner		333	(6)
Constructing the Maze Runner		333	(3)
Programming the Runner		336	(3)
Creating the Maze		339	(1)
Building a Maze Solver		339	(9)
Constructing the Maze Solver		339	(2)
Programming the Solver		341	(6)
Improving the Program		347	(1)
Summary		348	(1)
Drawing and Writing		349	(24)
Introduction		350	(1)
Creating a Logo Turtle		350	(11)
Building the Turtle		350	(5)
Programming the Turtle		355	(6)
Tape Writer		361	(8)
Building the Writer		361	(5)
Programming the Writer		366	(3)
What to Write		369	(1)
Further Suggestions		369	(2)
Copying		369	(1)
Emulating Handwriting		370	(1)
Learning by Example		370	(1)
Summary		371	(2)
Racing Against Time		373	(10)
Introduction		374	(1)
Hosting and Participating in Contests		374	(2)
Optimizing Speed		376	(1)
Drag Racing		376	(1)
Combining Speed with Precision		377	(4)
Line Following		378	(1)
Wall Following		379	(1)
Other Races		380	(1)
Summary		381	(2)
Hand-to-Hand Combat		383	(12)
Introduction		384	(1)
Building a Robotic Sumo		384	(4)
Setting the Rules		385	(1)
Maximizing Strength and Traction		386	(2)
Attack Strategies		388	(3)
Finding the Enemy		388	(1)
Using Speed		389	(1)
Using a Transmission		390	(1)
Other Sumo Tricks		391	(1)
Getting Defensive		391	(1)
Testing Your Sumo		392	(1)
Summary		393	(2)
Searching for Precision		395	(10)
Introduction		396	(1)
Precise Positioning		396	(1)
Shooting with Precision		397	(1)
Fine Motor Skills of Your Robot		398	(3)
Removing the Bricks		398	(1)
Freeing the Magnets		399	(2)
Fire Fighting in a Maze		401	(1)
Playing Soccer		402	(1)
Summary		403	(2)
Appendix A Resources		405	(16)
Introduction		406	(1)
Bibliography		406	(1)
General Interest Sites		407	(1)
Understanding LEGO Geometry		408	(1)
Playing with Gears		408	(1)
Controlling Motors		409	(1)
Reading Sensors		409	(2)
What's New with the NXT		411	(1)
Building Strategies		412	(1)
Programming the NXT		412	(1)
Playing Sounds and Music		413	(1)
Becoming Mobile		413	(1)
Getting Pumped: Pneumatics		414	(1)
Finding and Grabbing Objects		415	(1)
Doing the Math		415	(1)
Knowing Where You Are		416	(1)
Classic Projects		417	(1)
Building Robots that Walk		417	(1)
Robotic Animals		417	(1)
Solving a Maze		418	(1)
Drawing and Writing		418	(1)
Racing Against Time		419	(1)
Hand-to-Hand Combat		419	(1)
Searching for Precision		420	(1)
Appendix B Matching Distances		421	(6)
Appendix C Note Frequencies		427	(2)
Appendix D Math Cheat Sheet		429	(4)
Sensors		430	(1)
Averages		430	(1)
Interpolation		430	(1)
Gears, Wheels, and Navigation		431	(2)
Index		433

Mario Ferrari received his first Lego box around 1964, when he was 4. Lego was his favorite toy for many years, until he thought he was too old to play with it. In 1998, the Lego Mindstorms RIS set gave him reason to again have Lego become his main addiction. Mario believes Lego is the closest thing to the perfect toy. He is Managing Director at EDIS, a leader in finishing and packaging solutions and promotional packaging. The advent of the MINDSTORMS product line represented for him the perfect opportunity to combine his interest in IT and robotics with his passion for LEGO bricks, which started during his early childhood. Mario has been a very active member of the online MINDSTORMS community from the beginning and has pushed LEGO robotics to its limits. Mario holds a bachelor's degree in Business Administration from the University of Turin and has always nourished a strong interest for physics, mathematics, and computer science. He is fluent in many programming languages and his background includes positions as an IT manager and as a project supervisor. Mario estimates he owns over 60,000 Lego pieces. Mario works in Modena, Italy, where he lives with his wife Anna and his children Sebastiano and Camilla. Giulio Ferrari is a student in Economics at the University of Modena and Reggio Emilia, where he also studied Engineering. He is fond of computers and has developed utilities, entertainment software, and Web applications for several companies. Giulio discovered robotics in 1998, with the arrival of MINDSTORMS, and held an important place in the creation of the Italian LEGO community. He shares a love for LEGO bricks with his oldest brother Mario, and a strong curiosity for the physical and mathematical sciences. Giulio also has a collection of 1200 dice, including odd-faced dice and game dice. He studies, works, and lives in Modena, Italy. Dave Astolfo (GIS A.S.) is a Project Manager / Business Analyst with the technical arm of a North American environmental consulting company. He currently provides project management, technical consulting, database design and software architecture with a focus on Geographic Information Systems ranging from desktop mapping software, web mapping portals and mobile software applications. His specialties range from database modeling, software design / architecture. Dave is a key contributor to the business development and implementation of products and services. As such, he develops enterprise-wide technology solutions and methodologies focused on client organizations. Dave holds a bachelors degree from Trent University and is a certified Geographic Information Systems Applications Specialist holding a certificate from Sir Sandford Fleming College. In early 2006, Dave was invited by Lego to participate in the Lego Mindstorms Developer Program (MPD) to help Lego beta test the pre-release of the Lego Mindstorms NXT robotics system. After the release of the NXT, Dave was invited back to participate in the Lego Mindstorms Community Partner Program (MCP) to work with Lego in developing the product further while and providing an ear to the community. Dave has been involved with Lego all of his life, and has been working with the Mindstorms product since the initial release of the Lego Mindstorms Robotics Invention System (RIS) in 1998. Dave is well known for building a Mindstorms domino-placing robot which was published in a previous Syngress book (10 Cool Lego Ultimate Builders Lego Mindstorms Robots). Since then, he has created newer versions with a more recent NXT version being used by Lego marketing staff in Europe. Visit Daves site, www.plastibots.com, for more information on his work. Daniel T. Barry (M.D., Ph.D.) is a former NASA astronaut who was a crew member aboard the Space Shuttles Discovery and Endeavor. He logged more than 734 hours in space, including four spacewalks totaling 25 hours and 53 minutes. He holds a BS degree in electrical engineering from Cornell University; a masters of engineering degree and a master of arts degree in electrical engineering/computer science from Princeton University; a doctorate in electrical engineering/computer science from Princeton University; and a doctorate in medicine from the University of Miami in 1982. Organizations to which he belongs include the Institute of Electrical and Electronic Engineers (IEEE), the American Association of Electrodiagnostic Medicine (AAEM), the American Academy of Physical Medicine and Rehabilitation (AAPMR), the Association of Academic Physiatrists (AAP), and the Association of Space Explorers. He holds five patents, has written 50 articles in scientific journals, and has served on two scientific journal editorial boards. Dr. Barry retired from NASA in April 2005 to start his own company, Denbar Robotics, where he currently builds robots. Dr. Barry currently lives in South Hadley, MA. Bryan Bonahoom is a LEGO MINDSTORMS enthusiast. He is a member of the Lafayette LEGO Robotics Club and one of the original team that developed the Great Ball Contraption. Bryan is also cofounder of Brickworld. Bryan was selected by LEGO in 2006 as a member of the MDP and later as a member of the MINDSTORMS Community Partners (MCP). Bryan was also awarded the Best Robot Design Trophy at the 2005 AFOL Tournament at LEGO headquarters as a member of Team Hassenplug. Bryan is possibly most well known for the creation of an NXT-based robot that plays tic-tac-toe with a human opponent. Sivan Toledo is Associate Professor of Computer Science in Tel-Aviv University in Israel. He holds a BSc degree in Math and Computer Science and an MSc degree in Computer Science, both from Tel-Aviv University, and a PhD in Computer Science from the Massachusetts Institute of Technology. He authored more than 50 scientific papers and one textbook. He serves on the editorial boards of the SIAM Journal of Scientific Computing and of Parallel Computing. Larry Whitman (Ph.D., P.E.) is an Associate Professor of Industrial and Manufacturing Engineering at Wichita State University. Larry promotes engineering in every context possible. He is especially interested in promoting the technical literacy of all citizens, not just those who intend to be engineers. To this end, he and several colleagues at Wichita State have developed a course using LEGO MINDSTORMS in a hands-on environment to demonstrate basic engineering skills to nonengineering undergraduates. He also coordinates a LEGO MINDSTORMS challenge competition for middle school students. Finally, he promotes engineering by training his two sons, Joshua and David, to love building LEGO robots. Larry holds bachelor's and master's degrees from Oklahoma State University. After spending 10 years in the aerospace industry as a practicing engineer, he completed his Ph.D. from the University of Texas at Arlington. Joshua Whitman is a home-schooled eighth-grader from Wichita, KS. He has been building with LEGO bricks for as long as he can remember. He received his first MINDSTORMS RCX kit at age eight. He has participated in numerous robotics groups, clubs, and classes. He competed on a team in WSUs MINDSTORMS Robotics Challenge for two years. His team won the first-place trophy both times. As an experienced member of the team, he had to learn how to help teach the newer kids about MINDSTORMS. He was a part of the first winning team to use an NXT to compete in the challenge. His favorite (and most impressive) creation is a robot that can actually lock and unlock his room through a rotation sensor combination lock. The system is surprisingly secure, and 99.9 percent foolproof. He loves programming more than anything else in robotics. His current project involves using the NXT display as a screen for simple videogames like Pong. Guy Ziv is now finishing his graduate studies in biological physics at the Weizmann Institute of Science in Israel. He holds a bachelors degree in math and physics from the Hebrew University of Jerusalem and a masters degree in physics from the Weizmann Institute. Guy has been working in the field of measurement and automation for several years. He is an experienced LabView programmer and was a beta tester of NI LabView toolkit for NXT and MINDSTORMS NXT v. 1.1. Guy is the author and editor of NXTasy.org, the second largest NXT community site, and he moderates NXTasy.orgs repository and forums. John Brost had a passion for LEGO and all things mechanical at an early age. However, the interest waned, and like most adult LEGO fans, John went through his dark ages” in high school and while attending Purdue University. The release of the Star Wars LEGO sets brought a renewed interest in LEGO to John. But it was a chance encounter with an announcement of a LEGO Robotic Sumo competition being held locally that brought John back to LEGO 100 percent. It took only this event to get John hooked. Less than two weeks later, John had his first MINDSTORMS RIS kit, and he has been busily building robots and all sorts of mechanical LEGO contraptions ever since then. John has participated in all types of MINDSTORMS competitions, winning a few here and there. He has also been a coach for LafLRCs (Lafayette LEGO Robotics Club) FIRST LEGO League team for the past five years. In 2006, John was lucky enough to become a member of the LEGO MINDSTORMS Developer Program to test the MINDSTORMS NXT. Currently, John is a moderator on LEGOs NXTlog Web site. Rebeca Dunn-Krahn is a member of a working group at the University of Victoria dedicated to increasing awareness and understanding of computer science among children and young adults. She is currently producing a short documentary film about these outreach efforts that include free robotics festivals using LEGO MINDSTORMS. Rebeca has also worked in quality assurance and as a Java developer. Rebeca holds a bachelors degree in computer science and biochemistry from the University of Victoria and lives in Victoria, Canada, with her family. Richard Li is one of two nonadult contributors to Building Robots with LEGO MINDSTORMS NXT. He is currently a seventh-grader at Beck Academy and heads two award-winning FIRST LEGO League (FFL) teams. They have been honored with the Champions Award on several occasions and are ranked as two of the top teams yearly. When not working with his FLL teams, he experiments with his own robots at home. He would like to thank his parents, Lin and Liang-Hong, for buying him his LEGOs and dealing with him as he stayed up late several nights to meet his deadline for this book. Richard currently resides in Simpsonville, SC. Christopher Dale Minamyer (Bachelor of Science in Mechanical Engineering, University of Arizona, 2007) began studying mechanical engineering during the fall of 2002 and graduated from the University of Arizona in May 2007. A lifelong LEGO fan, Chris has been building with LEGO for 20 years. For the past four years Chris was an instructor of LEGO Robotics at Ventana Vista Elementary School in Tucson, AZ. During this time he instructed more than 300 students in grades one through five in LEGO MINDSTORMS RCX and NXT. In addition Chris is a founding member of the Tucson LEGO Club Masters Group and the head coach. Chris has been a FIRST LEGO League coach for the past four years. In that time the teams he coached have won the Robot Performance award (2004) and the Research Quality award (2005) for the state of Arizona. In addition Chris received the Adult coach/mentor award (2005) and the Appreciation award (2006). Deepak Patil developed interest in LEGO robotics when the original LEGO MINDSTORMS kit was introduced in 1998. Since then Deepak has coached FLL teams and has conducted several robotics workshops with LEGO MINDSTORMS. Deepak has a masters degree in Industrial Design from IIT Bombay and has designed user interfaces for diverse products, including programmable logic controllers, telephony software, and multimedia systems. Deepak has worked for Cisco and other leading technology companies, and he has led technology projects with globally interspersed teams of engineers. Mac Ruiz is a retired construction superintendent. His work entailed problem solving and coordinating of off-site engineers and subcontractors with the projects realities. He also has experience in fabrication of farm equipment from his familys dealership. This included steel fabrication and mechanicals. Christian Siagian is working toward a Ph.D. degree in Computer Science at the University of Southern California (USC). He is involved in the Beobot Project that develops a biologically inspired vision-based mobile-robot localization and navigation system. His research interests include robotics and computer and biological vision. As a teaching assistant for CS445 Introduction to Robotics at USC, Christian develops laboratory curriculum to prepare undergraduates for research in robotics. Christian also volunteers for after-school programs at St. Agnes Parish School and EPICC in Los Angeles. These programs use robotics to promote interest in science and mathematics in elementary and middle school students. Christian holds a bachelors degree from Cornell University in Computer Science and is a member of the IEEE. Dick Swan is an embedded software consultant. He partnered with the Robotics Academy at Carnegie Mellon University in developing the RobotC programming environment for the NXT. He also codeveloped with Tufts University the Robolab programming environment for the NXT. Dick has 30 years experience in software and hardware projects, including embedded systems, telephone systems, and compilers. Dick has both a bachelors and masters degree in Computer Science from the University of Waterloo and is a member of the IEEE.