Modify the generated code as follows:

• Add the following imports:

  import edu.wpi.first.wpilibj.Encoder;
  import com.ctre.phoenix.motorcontrol.can.*; // for Hazelnut
  import edu.wpi.first.wpilibj.Talon;         // for Macadamia
  

• Declare variables for the Encoders and Motor controllers in the Robot class

    // Uncomment next 2 lines for PWM motor controllers (Macademia)
    // private Talon leftMotor, rightMotor;
    // private Encoder leftEncoder, rightEncoder;
  
    // Uncomment next line for CAN motor controllers (Hazelnut)
    // private WPI_TalonSRX leftMotor, rightMotor;
  

• In robotInit() instantiate the Encoder and Motor objects
  • For PWM Motor Controller robots (Macadamia):

      // Quadrature encoder has A and B channels connected to DIO0,1, DIO2,3
      leftEncoder = new Encoder(0, 1);
      rightEncoder = new Encoder(2, 3);
      // Peanut wheels are 7.5" in diameter
      // Encoders provide 1 count per degree of rotation
      leftEncoder.setDistancePerPulse((3.141592*7.5)/360);
      rightEncoder.setDistancePerPulse((3.141592*7.5)/360);
      // PWM motor controllers connected to PWM0, PWM1
      leftMotor = new Talon(0);
      rightMotor = new Talon(1);
    

  • For CAN Motor Controller robots (Hazelnut):

      // CAN motor controllers connected to CAN bus (addrs 3,4)
      leftMotor = new WPI_TalonSRX(3);
      rightMotor = new WPI_TalonSRX(4);
      // clear any previously configured settings
      leftMotor.configFactoryDefault();
      rightMotor.configFactoryDefault();
      // Encoders are connected directly to the motor controllers
      leftMotor.configSelectedFeedbackSensor(FeedbackDevice.QuadEncoder);
      rightMotor.configSelectedFeedbackSensor(FeedbackDevice.QuadEncoder);
    

• For PWM controller robots (Macadamia),
  in robotPeriodic() display the encoder values:

    SmartDashboard.putNumber("Left", leftEncoder.getDistance());
    SmartDashboard.putNumber("Right", rightEncoder.getDistance());
  

• For CAN motor controllers (Hazelnut):
  • First add the following new method to the Robot class:

       double raw2inches(int raw_count, int counts_per_rotation, double wheel_diameter) {
          return (raw_count / counts_per_rotation) * (3.141492 * wheel_diameter);
       }
    

  • Add the following to the robotPeriodic() method; note the use of the ​getSelectedFeedbackSensor() method of the motor controller object which returns raw encoder counts:

       // Encoders connected to CAN controller return raw counts
       int l_raw = leftMotor.getSelectedSensorPosition();
       int r_raw = rightMotor.getSelectedSensorPosition();
       // display distances on smart dashboard
       SmartDashboard.putNumber("Left", raw2inches(l_raw, 360*2, 7.5));
       SmartDashboard.putNumber("Right", raw2inches(r_raw, 360*2, 7.5));
    

• In autonomousInit() reset the encoder counts and start the motors:

    // For PWM controllers (Macadamia) uncomment the next 2 lines to reset encoder counts to 0
    // leftEncoder.reset();
    // rightEncoder.reset();
    // start motors turning forward at 20% power
    leftMotor.set(0.20);
    // to go forward, left motor turns clockwise, right motor counter-clockwise
    rightMotor.set(-0.20);
  

• In the default section of autonomousPeriodic() stop if we've gone the desired distance. Notice our first use of the logical OR operator (||) to test whether either of two conditions is true
  • For PWM motor controllers:

          if ((leftEncoder.getDistance() > 36.0) || 
              (rightEncoder.getDistance() > 36.0)) {
             leftMotor.stopMotor();
             rightMotor.stopMotor();
          }
    

  • For CAN motor controllers:

          int l_raw = leftMotor.getSelectedSensorPosition();
          int r_raw = rightMotor.getSelectedSensorPosition();
          if ((raw2inches(l_raw, 360*2, 7.5) > 36.0) || 
              (raw2inches(r_raw, 360*2, 7.5) > 36.0)) {
             leftMotor.stopMotor();
             rightMotor.stopMotor();
          }