Programming, Controls & Sensors

Code the robot with WPILib — plus sensors, vision & control.

The Programming & Software branch is where robot hardware comes to life. FRC programmers use WPILib (the official robotics library) to read sensors and controllers, drive motors, run autonomous routines, and tune precise closed-loop control. This guide takes a motivated beginner from installing the toolchain to writing a clean command-based robot with PID/feedforward control, trajectory following, odometry, and simulation. Every API, part name, and tool is verified against current WPILib, CTRE Phoenix 6, and REVLib 2025/2026 documentation so you learn what teams actually ship today.

13 modules 51 lessons

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Curriculum

A beginner-friendly primer that builds the core programming and Java fundamentals every newcomer needs before writing a single line of FRC robot code. Start from absolute zero with variables, control flow, and objects, then learn why FRC robots are programmed in Java and how to read the WPILib library you'll lean on all season. Complete this before diving into the department's main robot-code lessons.

What you'll learn

Install the WPILib toolchain, FRC Game Tools, and Driver Station, then build and deploy code to a roboRIO
Understand WPILib's three officially supported text-based languages (Java, C++, Python/RobotPy) and the TimedRobot lifecycle
Structure and write a command-based robot with Subsystems, Commands, and Triggers
Control motors with vendor APIs: CTRE Phoenix 6 (Talon FX / Kraken X60 / Kraken X44) and REVLib 2025 (SPARK MAX/Flex, NEO/NEO Vortex)
Read joysticks and gamepads and bind buttons to commands
Tune PID feedback combined with feedforward and motion profiles
Generate and follow trajectories with PathPlanner and Choreo, and track position with odometry and vision-fused pose estimation
Test robot code without hardware using the WPILib Simulation GUI
How to read every common FRC sensor: limit switches, beam breaks, distance sensors, current sensing, encoders, and IMUs
The difference between relative (incremental) and absolute position sensing, and when each matters
How quadrature, duty-cycle/absolute, CAN, and analog sensor interfaces work and how they connect to the roboRIO
How to tune a PID controller methodically and combine it with feedforward (kS, kV, kA, kG)
How to characterize a mechanism with WPILib SysId to get real feedforward and PID gains
How AprilTags, Limelight (MegaTag2), and PhotonVision produce a field-relative pose
How to fuse vision with wheel/gyro odometry using a WPILib pose estimator and standard deviations

Tools & tech

WPILib (WPILibJ / WPILibC / RobotPy)Visual Studio Code with the WPILib extensionFRC Game Tools (NI): FRC Driver Station + roboRIO Imaging ToolGradle (GradleRIO build system)roboRIO 1.0 / roboRIO 2.0CTRE Phoenix 6 + Phoenix Tuner XREVLib + REV Hardware ClientPathPlanner (PathPlannerLib)Choreo (ChoreoLib)WPILib Simulation GUIElastic / Glass / Shuffleboard / AdvantageScopeXbox / Logitech F310 controllersWPILib (Java/C++) and WPILib VS CodeWPILib SysId (system identification tool)Shuffleboard / AdvantageScope / Glass (telemetry and tuning)CTRE Phoenix 6 + Phoenix Tuner X (CANcoder, Pigeon 2.0, Talon FX)REV Hardware Client (Spark MAX/Flex, NEO encoders, Through Bore Encoder, 2m Distance Sensor)Limelight (web UI, MegaTag2)PhotonVision (PhotonLib, PhotonPoseEstimator)Kauai Labs NavX2 / Analog Devices ADIS16470Playing With Fusion Time-of-Flight CAN sensor (VL53L1X)NetworkTables

Prerequisites

• Basic programming concepts (variables, methods, classes, if/loops) in any language — Java recommended
• A computer running Windows, macOS, or Linux (Windows is required to run the official Driver Station and roboRIO Imaging Tool, which ship in the NI FRC Game Tools)
• Familiarity with the robot's electronics is helpful but not required (see the Electrical branch)

Programming, Controls & Sensors

Curriculum

Programming Foundations: A Java Primer

Foundations: Tools, Languages, and Your First Robot Program

The Robot Program: Lifecycle and Command-Based Architecture

Motors, Sensors, and Closed-Loop Control

Autonomous: Odometry, Trajectories, and Simulation

Sensing Fundamentals: Digital, Analog, and CAN Inputs

Encoders: Measuring Position and Velocity

Gyros, IMUs, and Orientation

Closed-Loop Control: PID, Feedforward, and SysId

Computer Vision and Pose Estimation

Worked Examples and Mini-Projects

Common Mistakes and Troubleshooting

Advanced Techniques and Case Studies