Telemetry & Logging

Telemetry is how the robot reports information for tuning, debugging, and analysis. This page covers both SmartDashboard and AdvantageKit logging.

# SmartDashboard

SmartDashboard is the simplest telemetry system built into WPILib. It sends key-value pairs to NetworkTables and can be viewed from any tool.

# When to Use SmartDashboard

• Quick debugging
• Live values during testing
• Basic telemetry during matches

# Basic Example

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

public void periodic() {
    SmartDashboard.putNumber("Arm Angle", getAngle());
    SmartDashboard.putBoolean("Has Game Piece", hasPiece());
}

# Reading SmartDashboard Values

You can also read values from the dashboard (use sparingly):

double setpoint = SmartDashboard.getNumber("Arm Setpoint", 0.0);
pidController.setSetpoint(setpoint);

# AdvantageKit

AdvantageKit is a high-performance logging framework used for real-time telemetry and replay. It records everything the robot does for offline debugging.

# What AdvantageKit Provides

• Full match logging
• Automatic timestamping
• Replay simulator
• Plots, charts, time-aligned telemetry
• Swerve and path debugging

You don’t need to know all the special stuff - just therecordOutput()method.

# Basic Logger Example

import org.littletonrobotics.junction.Logger;

public void periodic() {
    Logger.recordOutput("Arm/Angle", getAngle());
    Logger.recordOutput("Arm/Target", targetAngle);
    Logger.recordOutput("Intake/HasPiece", hasPiece());
}

# Logging a Complex Object

AdvantageKit supports Pose2d, Rotation2d, and other geometry types automatically.

Logger.recordOutput("Drive/Pose", drivetrain.getPose());

# Logging Motor/Encoder Data

Logger.recordOutput("Arm/MotorTemp", motor.getTemperature());
Logger.recordOutput("Arm/EncoderPosition", encoder.getPosition());

# Best Practices

# What to Log

• Subsystem states (enabled, disabled, idling)
• Sensor values (encoders, limit switches)
• Odometry / robot pose

# Use Namespace Folders

…and DON’T change the spelling or capitalization.

Logger.recordOutput("Arm/Angle", angle);
Logger.recordOutput("Arm/Target", target);
Logger.recordOutput("Drive/LeftVelocity", leftVel);