Indexer Hoard/Burst State Machine

Disclaimer: WIP and untested on 2026 hardware; tune speeds, thresholds, and sensor logic on your robot. Custom code built on WPILib APIs (not official WPILib sample).

Purpose: Align fuel handling with hub state: hoard when inactive, auto-feed when active, clear jams fast.

What it does

• Two modes: HOARD (intake fills buffer, holds) and BURST (feeds shooter/hub).
• Jam detection via beam break (preferred) or motor current spike fallback.
• Auto-switches to BURST when hub becomes active, back to HOARD when inactive.

Code (Java/WPILib Command)

public class IndexerCommand extends Command {
  public enum Mode { HOARD, BURST }
  private final IndexerSubsystem indexer;
  private final Supplier<HubShiftTimer.HubState> hubState;
  private Mode mode = Mode.HOARD;
  private final Timer jamTimer = new Timer();

  public IndexerCommand(IndexerSubsystem indexer, Supplier<HubShiftTimer.HubState> hubState) {
    this.indexer = indexer;
    this.hubState = hubState;
    addRequirements(indexer);
  }

  @Override
  public void initialize() {
    mode = Mode.HOARD;
    jamTimer.reset();
  }

  @Override
  public void execute() {
    // Mode switch on hub state
    if (hubState.get() == HubShiftTimer.HubState.ACTIVE) mode = Mode.BURST;
    else mode = Mode.HOARD;

    boolean jam = isJammed();

    switch (mode) {
      case HOARD -> {
        if (indexer.isFull()) {
          indexer.stop();
        } else {
          indexer.feedIn();
        }
      }
      case BURST -> {
        if (jam) {
          indexer.reverse();
        } else {
          indexer.feedOut();
        }
      }
    }
  }

  private boolean isJammed() {
    // Prefer sensor
    if (indexer.hasBeamBreak() && indexer.beamBrokenTooLong(0.5)) return true;
    // Fallback current spike
    return indexer.getMotorCurrent() > 40.0;
  }

  @Override
  public void end(boolean interrupted) {
    indexer.stop();
  }
}

IndexerSubsystem sketch

public class IndexerSubsystem extends SubsystemBase {
  private final TalonFX motor = new TalonFX(10);
  private final DigitalInput beam = new DigitalInput(0);
  private final Timer beamTimer = new Timer();

  public void feedIn() { motor.set(ControlMode.PercentOutput, 0.4); }
  public void feedOut() { motor.set(ControlMode.PercentOutput, -0.6); }
  public void reverse() { motor.set(ControlMode.PercentOutput, -0.4); }
  public void stop() { motor.set(ControlMode.PercentOutput, 0.0); }

  public boolean hasBeamBreak() { return true; }
  public boolean isFull() { return beam.get(); } // adjust logic
  public boolean beamBrokenTooLong(double sec) { return beamTimer.hasElapsed(sec); }
  public double getMotorCurrent() { return motor.getStatorCurrent(); }

  @Override
  public void periodic() {
    if (beam.get()) beamTimer.start();
    else { beamTimer.stop(); beamTimer.reset(); }
  }
}

Parameters to tune

• Speeds: feed in/out percentages.
• Jam thresholds: beam break duration, current spike.
• Buffer “full” definition: sensor count or time.

How to test

• Bench: simulate hub active/inactive toggles; confirm mode flips HOARD/BURST.
• Feed 10 fuel; measure time per shift and success rate; induce jams (block rollers) to see reversals.

Pitfalls

• Ensure sensor logic matches wiring (beam break true vs false).
• Add current limit on motor to avoid brownouts during reverse.