Simple Ultrasonic Program

Continuously reads ultrasonic sensors and displays ranges on smart dashboard

1. Create a new project named Ultrasonic2.
2. Download the attached Ultrasonic2537.java and save it in the src/main/java/frc/robot folder. This file is needed because the default Ultrasonic class provided with WPILib is defective and does not work with more than one ultrasonic sensor.
3. Replace the auto-generated Robot.java class with the one below

• Notice that we don't need to import the Ultrasonic2537 class because it is declared to be in the same package as the Robot class (package frc.robot).

/*----------------------------------------------------------------------------*/
/* Copyright (c) 2017-2018 FIRST. All Rights Reserved.                        */
/* Open Source Software - may be modified and shared by FRC teams. The code   */
/* must be accompanied by the FIRST BSD license file in the root directory of */
/* the project.                                                               */
/*----------------------------------------------------------------------------*/

package frc.robot;

import edu.wpi.first.wpilibj.TimedRobot;
import edu.wpi.first.wpilibj.smartdashboard.SendableChooser;
import edu.wpi.first.wpilibj.smartdashboard.SmartDashboard;

/**
 * The VM is configured to automatically run this class, and to call the
 * functions corresponding to each mode, as described in the TimedRobot
 * documentation. If you change the name of this class or the package after
 * creating this project, you must also update the build.gradle file in the
 * project.
 */
public class Robot extends TimedRobot {
  private static final String kDefaultAuto = "Default";
  private static final String kCustomAuto = "My Auto";
  private String m_autoSelected;
  private final SendableChooser<String> m_chooser = new SendableChooser<>();
  private Ultrasonic2537 front, rear;

  /**
   * This function is run when the robot is first started up and should be used
   * for any initialization code.
   */
  @Override
  public void robotInit() {
    m_chooser.setDefaultOption("Default Auto", kDefaultAuto);
    m_chooser.addOption("My Auto", kCustomAuto);
    SmartDashboard.putData("Auto choices", m_chooser);

    front = new Ultrasonic2537(8, 9);
    rear = new Ultrasonic2537(5, 4);
    // setting automatic mode applies to all ultrasonics
    front.setAutomaticMode(true);
  }

  /**
   * This function is called every robot packet, no matter the mode. Use this for
   * items like diagnostics that you want ran during disabled, autonomous,
   * teleoperated and test.
   *
   * <p>
   * This runs after the mode specific periodic functions, but before LiveWindow
   * and SmartDashboard integrated updating.
   */
  @Override
  public void robotPeriodic() {
    if (front.isRangeValid())
       SmartDashboard.putNumber("front distance", front.getRangeInches());
    if (rear.isRangeValid())
       SmartDashboard.putNumber("rear distance",  rear.getRangeInches());
  }

  /**
   * This autonomous (along with the chooser code above) shows how to select
   * between different autonomous modes using the dashboard. The sendable chooser
   * code works with the Java SmartDashboard. If you prefer the LabVIEW Dashboard,
   * remove all of the chooser code and uncomment the getString line to get the
   * auto name from the text box below the Gyro
   *
   * <p>
   * You can add additional auto modes by adding additional comparisons to the
   * switch structure below with additional strings. If using the SendableChooser
   * make sure to add them to the chooser code above as well.
   */
  @Override
  public void autonomousInit() {
    m_autoSelected = m_chooser.getSelected();
    System.out.println("Auto selected: " + m_autoSelected);
  }

  /**
   * This function is called periodically during autonomous.
   */
  @Override
  public void autonomousPeriodic() {
    switch (m_autoSelected) {
    case kCustomAuto:
      // Put custom auto code here
      break;
    case kDefaultAuto:
    default:
      // Put default auto code here
      break;
    }
  }

  /**
   * This function is called periodically during operator control.
   */
  @Override
  public void teleopPeriodic() {
  }

  /**
   * This function is called periodically during test mode.
   */
  @Override
  public void testPeriodic() {
  }
}