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 of this project. The custom Ultrasonic class is needed because the 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 sensor on DIO8/9 and rear sensor on DIO5/4 (Trig/Echo)
    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() {
  }
}