The Finch Robot and the While Loop

1
The Finch Robot and the While Loop

• Pepper

2
The Robot

• Developed by Carnegie Mellon students to teach CS
• Supports many compilers, including Java
• Web site http//www.finchrobot.com/
• Why Illustrate while and do /while loops with
  physical example
• Why 2 See how hardware and physical actions can
  be controlled with code
• Lab group practice
• Extra One robot available for creating game
• Will need to learn methods
• May need to debug issues
• Will it help you learn for the final?

3
Hardware

• Input Sensors
• Obstacles
• Light
• Accelerometer (how fast is it going)
• Temperature
• Output
• Wheels turn
• LED lights
• Speaker
• Power
• Long USB Cord

4
Installing

• Download Java package from http//www.finchrobot.c
  om/Creating,20Compiling,20and20Running20Progra
  ms20for20Finch/bluej
• Place it in the folder you want to use
• Unzip it
• Open sample project in sourceFiles bluej.pkg
• Create your own package inside sample project
• (or add jar file finch.jar to bluej via
  preferences Or add finch.jar to the libs folder
  inside SourceFiles)

5
Make a Finch Controller

• Bring in the knowledge
• import edu.cmu.ri.createlab.terk.robot.finch.Finch
  
• Create a finch object that knows finch commands
• Finch myFinch new Finch()
• Always end with quit and exit
• myFinch.quit()
• System.exit(0)

6
Controlling commands

• Set Finch Beak Color
• myFinch.setLED(red,green,blue) // 0 to 255
• Make Finch Speak
• myFinch.saySomething("The Finch will say this.")
• Make Finch Move
• myFinch.setWheelVelocities(left,right,time)//
  -255 to 255 time is in milliseconds
• // negative number rolls backwards
• // hold the cord or it may have difficulty

7
Simple program

• package Pepper
• import edu.cmu.ri.createlab.terk.robot.finch.Finch
  
• public class FinchSimple
• public static void main(final String args)
  
• // Instantiating the Finch object
• Finch myFinch new Finch()
• myFinch.setWheelVelocities(255,255,1000)
  
• myFinch.saySomething(I am now All
  Done")
• // Always end your program
• myFinch.quit()
• System.exit(0)

8
Get Finch Sense Information

• Obstacles All true/false
• isObstacle()
• isObstacleLeftSide()
• isObstacleRightSide()
• Light All true/false, but using light level
  threshold. Returns true if less than the
  threshold
• isRightLightSensor(10)
• isLeftLightSensor(10)
• In dark, it will be true up to about 4
• In light, it will be true up to about 40
• Ex if (myFinch.isRightLightSensor(10) true)
  System.out.println(It is light out)else
  System.out.println(It is dark out)

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Make it do an action while a condition is true

• Keep moving forward until it senses an obstacle
• while ( myFinch.isObstacle() false )
  myFinch.setWheelVelocities(255,255,200)
• // then back up
• myFinch.setWheelVelocities(-255,-255,1000)

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Another - Make it do an action while a condition
is true

• Spin until the lights turn off
• while (myFinch.isRightLightSensor(10) true)
  myFinch.setWheelVelocities(255,-255,1000)
• // when the lights are out, this will be false
• // when the lights are on, this will be true
• // could say spin while lights are on
• // WILL NOT SPIN AT ALL IF LIGHTS OFF

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Do While

• Spin at least once, and then keep spinning until
  the lights turn off
• do
• myFinch.setWheelVelocities(255,-255,100
  0)
• while (myFinch.isRightLightSensor(10)
  true)
• // run with lights off see one spin first

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Get orientation info

• Orientation All true/false
• isFinchLevel()
• isFinchUpsideDown()
• isBeakDown()
• isBeakUp()
• isLeftWingDown()
• isRightWingDown()

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Your Takeaway

• Difference between while and do while
• Creating an object of a class gives your program
  powerful tools
• A sense of how hardware can be controlled by code
• Perhaps a desire to code your game using this
  little robot

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Your Turn

• Probably not needed, but see finch.jar in
  preferences
• Download java finch package
• http//www.finchrobot.com/Creating,20Compiling,2
  0and20Running20Programs20for20Finch/bluej
• New class
• Import above class
• import edu.cmu.ri.createlab.terk.robot.finch.Finch
  
• Inside main method, create a finch object
• Finch myFinch new Finch()
• Close your finch at the end of main
• myFinch.quit()
• System.exit(0)
• Add code to make it move right and test.
• Then make it do something until it hits a wall.