Get PDH current from singleton RobotContainer instance

src/main/java/frc/robot/Robot.java

@@ -2,6 +2,8 @@
 
 package frc.robot;
 
+import static frc.robot.RobotContainer.getRobotContainer;
+
 import edu.wpi.first.wpilibj.DataLogManager;
 import edu.wpi.first.wpilibj.DriverStation;
 import edu.wpi.first.wpilibj.TimedRobot;
@@ -11,13 +13,12 @@
 public class Robot extends TimedRobot {
 
   private Command m_autonomousCommand;
-  private RobotContainer m_robotContainer;
 
   @Override
   public void robotInit() {
     // Instantiate our RobotContainer.  This will perform all our button bindings, and put our
     // autonomous chooser on the dashboard.
-    m_robotContainer = new RobotContainer();
+    getRobotContainer();
 
     // Starts recording to data log
     // https://docs.wpilib.org/en/stable/docs/software/telemetry/datalog.html#logging-joystick-data
@@ -28,7 +29,7 @@ public void robotInit() {
   @Override
   public void robotPeriodic() {
     CommandScheduler.getInstance().run();
-    m_robotContainer.periodic();
+    getRobotContainer().periodic();
   }
 
   @Override
@@ -39,7 +40,7 @@ public void disabledPeriodic() {}
 
   @Override
   public void autonomousInit() {
-    m_autonomousCommand = m_robotContainer.getAutonomousCommand();
+    m_autonomousCommand = getRobotContainer().getAutonomousCommand();
 
     if (m_autonomousCommand != null) {
       m_autonomousCommand.schedule();
@@ -55,7 +56,7 @@ public void teleopInit() {
       m_autonomousCommand.cancel();
     }
 
-    m_robotContainer.teleopInit();
+    getRobotContainer().teleopInit();
   }
 
   @Override

src/main/java/frc/robot/RobotContainer.java

@@ -31,12 +31,21 @@
 
 public class RobotContainer {
 
+  private static RobotContainer INSTANCE = null;
+
+  public static RobotContainer getRobotContainer() {
+    if (INSTANCE == null) {
+      INSTANCE = new RobotContainer();
+    }
+    return INSTANCE;
+  }
+
   private final PowerDistribution m_PowerDistribution = new PowerDistribution(1, ModuleType.kRev);
 
   private final Drivetrain m_swerve = new Drivetrain();
   private final Arm m_arm = new Arm();
   private final Intake m_intake = new Intake();
-  private final Climber m_climber = new Climber(m_PowerDistribution);
+  private final Climber m_climber = new Climber();
 
   private final EventLoop m_loop = new EventLoop();
   private Joystick m_driver = new Joystick(OIConstants.kDriverControllerPort);
@@ -218,4 +227,15 @@ private int getSelectedAutonomousMode() {
     }
     return -1; // failure of the physical switch
   }
+
+  /**
+   * Gets the current drawn from the Power Distribution Hub by a CAN motor controller, assuming that
+   * (PDH port number + 10) = CAN ID
+   *
+   * @param CANBusPort The CAN ID of the motor controller
+   * @return Current in Amps on the PDH channel corresponding to the motor channel
+   */
+  public double getPDHCurrent(int CANBusPort) {
+    return m_PowerDistribution.getCurrent(CANBusPort - 10);
+  }
 }

src/main/java/frc/robot/climber/Climber.java

@@ -1,6 +1,5 @@
 package frc.robot.climber;
 
-import edu.wpi.first.wpilibj.PowerDistribution;
 import edu.wpi.first.wpilibj.XboxController;
 import edu.wpi.first.wpilibj.drive.DifferentialDrive;
 import edu.wpi.first.wpilibj2.command.Command;
@@ -11,15 +10,12 @@ public class Climber extends SubsystemBase {
 
   private ClimberSide[] m_actuators = new ClimberSide[2];
 
-  private final PowerDistribution m_pdp;
-
   DifferentialDrive m_differentialDrive;
 
-  public Climber(PowerDistribution pdp) {
+  public Climber() {
 
-    this.m_pdp = pdp;
-    m_actuators[0] = new ClimberSide("Left", ClimberConstants.kLeftMotorPort, m_pdp);
-    m_actuators[1] = new ClimberSide("Right", ClimberConstants.kRightMotorPort, m_pdp);
+    m_actuators[0] = new ClimberSide("Left", ClimberConstants.kLeftMotorPort);
+    m_actuators[1] = new ClimberSide("Right", ClimberConstants.kRightMotorPort);
 
     m_differentialDrive = new DifferentialDrive(m_actuators[0]::setPower, m_actuators[1]::setPower);
   }

src/main/java/frc/robot/climber/ClimberSide.java

@@ -1,5 +1,7 @@
 package frc.robot.climber;
 
+import static frc.robot.RobotContainer.getRobotContainer;
+
 import com.revrobotics.CANSparkBase;
 import com.revrobotics.CANSparkBase.IdleMode;
 import com.revrobotics.CANSparkLowLevel.MotorType;
@@ -10,7 +12,6 @@
 import edu.wpi.first.math.filter.Debouncer.DebounceType;
 import edu.wpi.first.math.filter.LinearFilter;
 import edu.wpi.first.math.trajectory.TrapezoidProfile;
-import edu.wpi.first.wpilibj.PowerDistribution;
 import edu.wpi.first.wpilibj.smartdashboard.SmartDashboard;
 import frc.robot.Constants.ClimberConstants;
 import frc.robot.Constants.ClimberConstants.CalibrationState;
@@ -36,15 +37,11 @@ public class ClimberSide {
 
   private CalibrationState m_calibrationState = CalibrationState.UNCALIBRATED;
 
-  private final PowerDistribution m_pdp;
-
-  public ClimberSide(String climberName, int climberMotorChannel, PowerDistribution pdp) {
+  public ClimberSide(String climberName, int climberMotorChannel) {
 
     this.climberName = climberName;
     this.motorChannel = climberMotorChannel;
 
-    this.m_pdp = pdp;
-
     m_climberMover = new CANSparkMax(motorChannel, MotorType.kBrushless);
 
     m_climberMover.restoreFactoryDefaults();
@@ -102,7 +99,7 @@ public void resetEncoder() {
   }
 
   public boolean getCurrentSenseState() {
-    return m_debouncer.calculate(getSparkMaxCurrent() > ClimberConstants.kMotorCurrentHardStop);
+    return m_debouncer.calculate(getOutputCurrent() > ClimberConstants.kMotorCurrentHardStop);
   }
 
   private boolean getUpperSoftLimitSwtichState() {
@@ -143,14 +140,17 @@ private double getPosition() {
   }
 
   /**
-   * @return Current in Amps, output of linear filter
+   * @return Current in Amps, output of motor controller
    */
-  private double getSparkMaxCurrent() {
+  private double getOutputCurrent() {
     return m_filter.calculate(m_climberMover.getOutputCurrent());
   }
 
-  private double getPdhCurrent() {
-    return m_pdp.getCurrent(motorChannel - 10);
+  /**
+   * @return Current in Amps, input to motor controller
+   */
+  private double getInputCurrent() {
+    return getRobotContainer().getPDHCurrent(motorChannel);
   }
 
   /**
@@ -166,8 +166,8 @@ public void periodic() {
         getName() + "MotorRotations", getPosition() / ClimberConstants.kPositionConversionFactor);
     SmartDashboard.putBoolean(getName() + "UpperSoftLimitState", getUpperSoftLimitSwtichState());
     SmartDashboard.putBoolean(getName() + "LowerSoftLimitState", getLowerSoftLimitSwtichState());
-    SmartDashboard.putNumber(getName() + "SparkMaxCurrent", addPolarity(getSparkMaxCurrent()));
-    SmartDashboard.putNumber(getName() + "PDHCurrent", addPolarity(getPdhCurrent()));
+    SmartDashboard.putNumber(getName() + "OutputCurrent", addPolarity(getOutputCurrent()));
+    SmartDashboard.putNumber(getName() + "InputCurrent", addPolarity(getInputCurrent()));
     SmartDashboard.putString(getName() + "CalibrationState", getCalibrationState().name());
   }