DC Motor Control

Introduction: A DC motor converts electrical power into continuous rotation for lifts, arms, intakes, and drive systems.

Basic theory: Motor power is set from -1.0 to 1.0. Negative values reverse direction, positive values move forward, and 0.0 stops. Clamping power is a safe beginner practice.

mport com.qualcomm.robotcore.eventloop.opmode.LinearOpMode;
        import com.qualcomm.robotcore.eventloop.opmode.TeleOp;
        import com.qualcomm.robotcore.hardware.DcMotor;
        
        /**
         * This OpMode demonstrates how to control a single DC motor
         * using the gamepad left stick Y-axis.
         */
        @TeleOp(name="DC Motor Control Demo", group="Training")
        public class DcMotorControlDemo extends LinearOpMode {
        
            private DcMotor armMotor;
        
            @Override
            public void runOpMode() {
                // --- Initialization Phase ---
                
                // Initialize the motor from the hardware map.
                // Change "armMotor" to match the name in your robot configuration.
                armMotor = hardwareMap.get(DcMotor.class, "armMotor");
                
                // Set the motor direction. 
                // FORWARD is usually clockwise, REVERSE is counter-clockwise.
                armMotor.setDirection(DcMotor.Direction.FORWARD);
        
                telemetry.addData("Status", "Initialized. Press Play to start.");
                telemetry.update();
        
                // Wait for the driver to press the "PLAY" button.
                waitForStart();
        
                // --- Run Phase ---
                while (opModeIsActive()) {
                    
                    // Read the vertical position of the left stick.
                    // Up is negative, so we negate it for intuitive control (Up = Positive Power).
                    double power = -gamepad1.left_stick_y;
                    
                    // Clamp the power between -0.8 and 0.8 as a safety limit.
                    power = Math.max(-0.8, Math.min(0.8, power));
        
                    // Apply the calculated power to the motor.
                    armMotor.setPower(power);
        
                    // Send feedback to the Driver Hub.
                    telemetry.addData("Motor Power", "%.2f", power);
                    telemetry.update();
                }
            }
        }
        

Power range: -1.0 reverse, 0.0 stop, 1.0 forward.