Building Mindstorms NXT Robots Dr. David Johnson School of

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Building Mindstorms NXT Robots

• Dr. David Johnson
• School of Computing

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What Is a Robot?
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Resources for Learning About Robots

• Web
• Wikipedia
• http//en.wikipedia.org/wiki/Robot
• New Scientist
• http//www.newscientist.com/article/dn9973-instant
  -expert-robots.html
• Youtube
• Many!
• MAKE magazine
• Boy Scout badge guide is quite nice and cheap
• Consider exercising your teams FLL skills by
  having them look at some of these resources

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Some Example Robots

• Big Dog
• http//www.youtube.com/watch?vb2bExqhhWRI
• Planetary Exploration
• http//www.youtube.com/watch?vnb2GsD7TAjUfeature
  related
• Home assistance
• http//www.youtube.com/watch?vGTxW3GWZ5hI
• Hobby
• http//www.youtube.com/watch?vzX09WnGU6ZY

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What Is a Robot?

• Sense
• Update information about the world
• Plan
• Modify original plan in response to this sensed
  information
• Act
• Move in the world or make a change in the world

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Mindstorms NXT

• Can it?
• Sense
• Plan
• Act

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Mindstorms NXT

• It can
• Sense
• Light intensity and color
• Sound intensity
• Button presses
• Distance to nearby objects
• Wheel revolutions
• Plan
• Act

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Mindstorms NXT

• It can
• Sense
• Plan
• Small computer brain
• the brick
• Graphical programming language
• Act

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Mindstorms NXT

• It can
• Sense
• Plan
• Act
• Three motors that turn

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Goals For Today

• Raise your comfort level with Mindstorms
• Building
• Programming
• There is no substitute for doing it
• Try some common tasks
• Wheeled robot
• Respond to sensors
• Maybe a taste of competition

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Testing Equipment

• Plug in motors, sensors
• A critical thing to know is the view program
• Let you read values from sensors without writing
  a custom program

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Building

• Not normal LEGO pieces
• Based on the Lego Technic build system
• Pegs and holes
• Can be frustrating
• Stable
• One peg makes a rotary joint
• Multiple pegs lock two pieces in place
• Strong
• Keep in close to the main body
• The wheel axes must not be wobbly and flex!

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Building Resources

• There are lots of instructions for building
  things online
• http//www.nxtprograms.com/
• Have the team try some out
• Learn things that work
• Then modify
• Dont get too distracted with NXT guitars, guns,
  etc.
• 5 minute bot
• A quick base
• Probably not good to adapt for competition

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Programming

• Programming teaches
• Breaking complex problems into solvable parts
• Precise thinking and specification
• Creative experimentation to discover and isolate
  problems
• Programs are designed on a base computer
• Downloaded by USB cable to the brick

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Programming the Brick

• LEGO Mindstorms NXT
• Default language for programming Mindstorms
• Designed to be friendly
• Nice tutorials
• Try them with your team
• Not based on traditional programming languages
• Easy to do very basic things
• More difficult to advance
• It does have some subtle actions that can cause
  confusion

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Learning to Use the Tutorial

• Each tutorial is structured as
• Challenge
• Build
• Program
• The mobile base from the tutorials is not my
  favorite
• Takes too long to build
• Difficult to modify

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A Quick Programming Tour

• Control goes along the path
• Each block performs some action
• Most blocks are very flexible
• Learn the options at the bottom panel
• Many actions continue until
• A sensor is triggered
• Time has passed
• A commanded result is finished

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A Quick Test

• Attach a motor to the brick (ports A,B,C)
• Attach a touch sensor to the brick (ports
  1,2,3,4)
• Write a program
• Move block
• Set duration to unlimited
• Wait until touch
• Move block
• Set the brakes
• Download to brick
• Run it

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Additional Resources

• There is a lot to learn, but you can get started
  pretty quickly
• I recommend
• Winning Design! LEGO Mindstorms NXT Design
  Patterns for Fun and Competition
• Most FLL-centric of the books
• Beginning to medium skill level
• If you dont have prior experience, I think you
  would be foolish not to look at this book.
• Parts of my FLL camp notes
• More for getting a novice team started

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Lets have a competition!

• Go through maze
• Stop before unknown finish wall
• How to solve?
• Detect or dead reckoning
• Development cycle
• Build, test, adjust, repeat
• Most kids do not understand how to test and
  modify something until it works

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Teams!