TeleOp Programming Concepts

beginner45 min

Overview of TeleOp Programming

TeleOp programming is the process of writing code that allows drivers to control the robot in real time using gamepads. In this lesson, you’ll learn how to read gamepad input, map controls to robot actions, and use telemetry for feedback.

Gamepad Input Handling

The gamepad1 and gamepad2 objects provide access to all the buttons, sticks, and triggers on the controllers. Reading these values lets you control motors, servos, and other mechanisms.

Example: Reading Gamepad Input

This snippet shows how to read joystick and button values from gamepad1.

double drive = -gamepad1.left_stick_y; // Forward/backward
double turn = gamepad1.right_stick_x;   // Turning
boolean aPressed = gamepad1.a;          // Button A
if (aPressed) {
    // Do something when A is pressed
}

Mapping Gamepad Inputs to Robot Actions

You can use gamepad input to control motors, servos, and other mechanisms. For example, you might use the left stick for driving and a button to control a claw.

Example: Mapping Controls to Drive and Servo

// Drive control
double leftPower = -gamepad1.left_stick_y;
double rightPower = -gamepad1.right_stick_y;
leftDrive.setPower(leftPower);
rightDrive.setPower(rightPower);
// Claw control
if (gamepad1.a) {
    clawServo.setPosition(1.0); // Open
} else if (gamepad1.b) {
    clawServo.setPosition(0.0); // Close
}

Telemetry for Debugging and Feedback

Telemetry lets you send data from your robot to the Driver Station for real-time feedback. Use telemetry.addData() to add information and telemetry.update() to send it. This is essential for debugging and for providing drivers with useful information during a match.

For more on telemetry, see FTC Docs: Telemetry or Telemetry Logging.

Example: Using Telemetry

telemetry.addData("Left Power", leftPower);
telemetry.addData("Right Power", rightPower);
telemetry.addData("Claw Position", clawServo.getPosition());
telemetry.update();

Practice Exercise: Custom TeleOp Controls

Write a TeleOp OpMode that uses the left stick to drive, the right stick to turn, and buttons A/B to open/close a claw. Add telemetry to display all relevant values. Refactor your code to use helper methods for each subsystem.

Map drive motors and a claw servo.
Read joystick and button values from gamepad1.
Set motor and servo power based on input.
Add telemetry for all controls.
Refactor code into helper methods.

Map drive motors and a claw servo

                  // Declare hardware components
private DcMotor leftDrive, rightDrive;
private Servo clawServo;

// Initialize in runOpMode()
leftDrive = hardwareMap.get(DcMotor.class, "left_drive");
rightDrive = hardwareMap.get(DcMotor.class, "right_drive");
clawServo = hardwareMap.get(Servo.class, "claw_servo");

// Show initialization status
telemetry.addData("Status", "Custom TeleOp Controls Ready");
telemetry.update();

Read joystick and button values from gamepad1

                  // Read joystick values for drive control
double drivePower = -gamepad1.left_stick_y;  // Forward/backward
double turnPower = gamepad1.right_stick_x;   // Left/right turning

// Read button values for claw control
boolean aPressed = gamepad1.a;  // Open claw
boolean bPressed = gamepad1.b;  // Close claw

// Display input values
telemetry.addData("Drive Power", "%.2f", drivePower);
telemetry.addData("Turn Power", "%.2f", turnPower);
telemetry.addData("Button A", aPressed);
telemetry.addData("Button B", bPressed);
telemetry.update();

Set motor and servo power based on input

                  // Calculate left and right motor powers
// Drive power controls forward/backward
// Turn power controls left/right turning
double leftPower = drivePower + turnPower;
double rightPower = drivePower - turnPower;

// Apply power limits to prevent motor damage
leftPower = Math.max(-1.0, Math.min(1.0, leftPower));
rightPower = Math.max(-1.0, Math.min(1.0, rightPower));

// Set motor powers
leftDrive.setPower(leftPower);
rightDrive.setPower(rightPower);

// Control claw servo based on button presses
if (aPressed) {
    clawServo.setPosition(1.0);  // Open claw
} else if (bPressed) {
    clawServo.setPosition(0.0);  // Close claw
}

Add telemetry for all controls

                  // Display all control values and robot status
telemetry.addData("=== DRIVE CONTROLS ===", "");
telemetry.addData("Drive Power", "%.2f", drivePower);
telemetry.addData("Turn Power", "%.2f", turnPower);
telemetry.addData("Left Motor Power", "%.2f", leftPower);
telemetry.addData("Right Motor Power", "%.2f", rightPower);

telemetry.addData("=== CLAW CONTROLS ===", "");
telemetry.addData("Button A (Open)", aPressed);
telemetry.addData("Button B (Close)", bPressed);
telemetry.addData("Claw Position", "%.2f", clawServo.getPosition());

telemetry.addData("=== ROBOT STATUS ===", "");
telemetry.addData("OpMode Active", opModeIsActive());
telemetry.addData("Match Time", "%.1f seconds", getRuntime());

telemetry.update();

Refactor code into helper methods

                  // Helper method for drive control
private void controlDrive() {
    double drivePower = -gamepad1.left_stick_y;
    double turnPower = gamepad1.right_stick_x;
    
    double leftPower = drivePower + turnPower;
    double rightPower = drivePower - turnPower;
    
    // Apply power limits
    leftPower = Math.max(-1.0, Math.min(1.0, leftPower));
    rightPower = Math.max(-1.0, Math.min(1.0, rightPower));
    
    leftDrive.setPower(leftPower);
    rightDrive.setPower(rightPower);
}

// Helper method for claw control
private void controlClaw() {
    if (gamepad1.a) {
        clawServo.setPosition(1.0);  // Open
    } else if (gamepad1.b) {
        clawServo.setPosition(0.0);  // Close
    }
}

// Helper method for telemetry
private void updateTelemetry() {
    telemetry.addData("Drive Power", "%.2f", -gamepad1.left_stick_y);
telemetry.addData("Turn Power", "%.2f", gamepad1.right_stick_x);
telemetry.addData("Left Motor", "%.2f", leftDrive.getPower());
telemetry.addData("Right Motor", "%.2f", rightDrive.getPower());
telemetry.addData("Claw Position", "%.2f", clawServo.getPosition());
telemetry.addData("Button A", gamepad1.a);
telemetry.addData("Button B", gamepad1.b);
telemetry.update();
}

Combine all tasks into a complete TeleOp OpMode

                  import com.qualcomm.robotcore.eventloop.opmode.LinearOpMode;
import com.qualcomm.robotcore.eventloop.opmode.TeleOp;
import com.qualcomm.robotcore.hardware.DcMotor;
import com.qualcomm.robotcore.hardware.Servo;

@TeleOp(name = "CustomTeleOpControls")
public class CustomTeleOpControls extends LinearOpMode {
    private DcMotor leftDrive, rightDrive;
    private Servo clawServo;

    @Override
    public void runOpMode() {
        // Initialize hardware
        leftDrive = hardwareMap.get(DcMotor.class, "left_drive");
        rightDrive = hardwareMap.get(DcMotor.class, "right_drive");
        clawServo = hardwareMap.get(Servo.class, "claw_servo");
        
        telemetry.addData("Status", "Custom TeleOp Controls Ready");
telemetry.addData("Instructions", "Left stick: Drive, Right stick: Turn, A/B: Claw");
telemetry.update();
        
        waitForStart();
        
        while (opModeIsActive()) {
            // Control drive system
            controlDrive();
            
            // Control claw
            controlClaw();
            
            // Update telemetry
            updateTelemetry();
        }
        
        // Stop motors when OpMode ends
        leftDrive.setPower(0);
        rightDrive.setPower(0);
    }
    
    // Helper method for drive control
    private void controlDrive() {
        double drivePower = -gamepad1.left_stick_y;
        double turnPower = gamepad1.right_stick_x;
        
        double leftPower = drivePower + turnPower;
        double rightPower = drivePower - turnPower;
        
        // Apply power limits
        leftPower = Math.max(-1.0, Math.min(1.0, leftPower));
        rightPower = Math.max(-1.0, Math.min(1.0, rightPower));
        
        leftDrive.setPower(leftPower);
        rightDrive.setPower(rightPower);
    }
    
    // Helper method for claw control
    private void controlClaw() {
        if (gamepad1.a) {
            clawServo.setPosition(1.0);  // Open
        } else if (gamepad1.b) {
            clawServo.setPosition(0.0);  // Close
        }
    }
    
    // Helper method for telemetry
    private void updateTelemetry() {
        telemetry.addData("=== DRIVE CONTROLS ===", "");
telemetry.addData("Drive Power", "%.2f", -gamepad1.left_stick_y);
telemetry.addData("Turn Power", "%.2f", gamepad1.right_stick_x);
telemetry.addData("Left Motor", "%.2f", leftDrive.getPower());
telemetry.addData("Right Motor", "%.2f", rightDrive.getPower());
        
telemetry.addData("=== CLAW CONTROLS ===", "");
telemetry.addData("Button A (Open)", gamepad1.a);
telemetry.addData("Button B (Close)", gamepad1.b);
telemetry.addData("Claw Position", "%.2f", clawServo.getPosition());
        
telemetry.addData("=== ROBOT STATUS ===", "");
telemetry.addData("Match Time", "%.1f seconds", getRuntime());
telemetry.update();
    }
}