Brownout Guard

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

Purpose: Prevent brownouts during bursts (fuel hoard/burst, climbs) by scaling outputs when voltage drops.

Code (Java/WPILib helper)

public class BrownoutGuard {
  private final double lowVoltage;
  private final double scale;
  private final Timer timer = new Timer();
  private boolean inGuard = false;

  public BrownoutGuard(double lowVoltage, double scale, double minHoldSec) {
    this.lowVoltage = lowVoltage;
    this.scale = scale;
    timer.reset(); timer.start();
  }

  public double guard(double requested) {
    double v = RobotController.getBatteryVoltage();
    if (v < lowVoltage) {
      inGuard = true;
      timer.reset();
    }
    if (inGuard && timer.get() > 0.5) { // hold guard for 0.5s minimum
      inGuard = false;
    }
    return inGuard ? requested * scale : requested;
  }
}

Usage

BrownoutGuard driveGuard = new BrownoutGuard(10.5, 0.7, 0.5);

// In drive code:
double scaled = driveGuard.guard(requestedPercent);
driveMotor.set(scaled);

Add current limits (example TalonFX)

SupplyCurrentLimitConfiguration limit =
    new SupplyCurrentLimitConfiguration(true, 40.0, 50.0, 0.1);
talon.configSupplyCurrentLimit(limit);

How to test

• On blocks: slam joysticks; watch voltage; confirm scale kicks in near 10.5 V.
• Burn-in: log voltage/current; verify fewer brownouts with guard enabled.

Pitfalls

• Don’t set lowVoltage too high or you’ll feel sluggish all match.
• Keep the guard window short; long scaling hurts responsiveness.