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FTC Programming Quick Start

Basic FTC Example: FTC Sample

In FTC, you can use Android Studio, OnBot Java, and Blockly to interact with your Limelight.

Most applications require less than 10 lines of code. Here's a quick overview of the process.

Basic Usage​

  1. Initialize your Limelight3A using the same name that you used during the Control Hub Setup step.
  2. Call pipelineSwitch() to select one of the 10 pipelines you configured using the web interface
  3. Call start() to start background results polling at 100 polls per second.
public class Teleop extends LinearOpMode {

    private Limelight3A limelight;

    @Override
    public void runOpMode() throws InterruptedException
    {
        limelight = hardwareMap.get(Limelight3A.class, "limelight");

        telemetry.setMsTransmissionInterval(11);

        limelight.pipelineSwitch(0);

        /*
         * Starts polling for data.
         */
        limelight.start();
        .
        .
  1. Call getLatestResult() in your autonomous and teleop loops to get the latest LLResult object
  2. Utilize LLResult's getTx(), getTy(), and getBotpose() to guide your robot.
    while (opModeIsActive()) {
        LLResult result = limelight.getLatestResult();
        if (result != null) {
            if (result.isValid()) {
                Pose3D botpose = result.getBotpose();
                telemetry.addData("tx", result.getTx());
                telemetry.addData("ty", result.getTy());
                telemetry.addData("Botpose", botpose.toString());
                .
                .

Advanced Usage​

  1. Advanced use-cases may call for the use of LLResult's getColorResults(), getFiducialResults(), etc.
    // print some data for each detected target
    if (result.isValid()) {
        // Access fiducial results
        List<LLResultTypes.FiducialResult> fiducialResults = result.getFiducialResults();
        for (LLResultTypes.FiducialResult fr : fiducialResults) {
            telemetry.addData("Fiducial", "ID: %d, Family: %s, X: %.2f, Y: %.2f", fr.getFiducialId(), fr.getFamily(),fr.getTargetXDegrees(), fr.getTargetYDegrees());
        }

        // Access color results
        List<LLResultTypes.ColorResult> colorResults = result.getColorResults();
        for (LLResultTypes.ColorResult cr : colorResults) {
            telemetry.addData("Color", "X: %.2f, Y: %.2f", cr.getTargetXDegrees(), cr.getTargetYDegrees());
        }
    }
  1. For maximum 3D localization accuracy, call updateRobotOrientation() and use getBotPose_MT2(). MegaTag2 is an IMU-Fused robot localizer that utilizes the imu to solve the ambiguity problem which is fundamental to all planar targets such as AprilTags.
    while (opModeIsActive()) {
        YawPitchRollAngles orientation = imu.getRobotYawPitchRollAngles();

        telemetry.addData("Yaw (Z)", "%.2f Deg. (Heading)", orientation.getYaw(AngleUnit.DEGREES));

        limelight.updateRobotOrientation(orientation.getYaw(AngleUnit.DEGREES));
        LLResult result = limelight.getLatestResult();
        if (result != null) {
            if (result.isValid()) {
                Pose3D botpose = result.getBotpose_MT2();
                .
                .

For more information, see the FTC Programming page