Sample TankDrive code for Robot in 1 Weekend 2015

RI1WTankDrive.java

/* Robot in 1 Weekend
 * September 12-13, 2015
 *
 * The following is a sample of code used during the Robot in 1 Weekend event (see the Ri3d channel
 * on YouTube: https://www.youtube.com/channel/UCgtwgUTTxuldvAGW1u8SDSA). It was written by
 * Christina Grajales (formerly Univ. of Auburn and team 1902) and AJ Foster (UCF and formerly
 * team 2425).
 *
 * Use of this code requires the Android Studio software and various packages. Please see the
 * documentation in the FTC App repository (https://github.com/ftctechnh/ftc_app). The following
 * Android Studio packages are needed via the SDK Manager:
 *
 * Tools:
 * - Android SDK Build-tools
 *   - 23.0.1 (preinstalled - can we uninstall?)
 *   - 21.1.2
 *   - 19.1
 *
 * Android 5.0.1 (API 21)
 * - SDK Platform
 * - Google APIs
 *
 * Android 4.4.2 (API 19)
 * - SDK Platform
 * - Google APIs (x86 System Image)
 * - Google APIs (ARM System Image)
 *
 * This file should be located in the src/main/java/com.../opmodes directory of the
 * FtcRobotController project (see https://github.com/ftctechnh/ftc_app). In order to use this
 * OpMode, you'll have to declare it in the FtcOpModeRegister class.
 *
 * We give you NO WARRANTY about the utility or safety of this code. It is up to you to learn and
 * understand what it does before using it on an operational robot.
 */


// Each OpMode must be included in this package.
package com.qualcomm.ftcrobotcontroller.opmodes;

// Include packages as necessary for predefined classes.
import com.qualcomm.robotcore.eventloop.opmode.OpMode;
import com.qualcomm.robotcore.hardware.DcMotor;
import com.qualcomm.robotcore.hardware.DcMotorController;


/* This public class represents our OpMode. Inside of it you will find a number of methods - some
 * are required, some are not. For more information about the structure of this class, see the
 * Javadocs in the ftc_app repo.
 */
public class RI1WTankDrive extends OpMode {

    // Define the left and right drive train motors. We will instantiate (set) these variables
    // below, in the init() method.
    DcMotor ri1w_drive_left;
    DcMotor ri1w_drive_right;

    // These variables will be used to set the drive train motor speed.
    double left_drive = 0.0;
    double right_drive = 0.0;

    // This variable will be used to decide whether to scale down the drive train speed.
    boolean scale_down = false;


    /* init() runs as soon as you arm the OpMode using the FTC Driver Station app. Use it to set
     * servos, calibrate sensors, or otherwise initialize your hardware.
     *
     * This method is required - if you do not have it, the OpMode cannot be run.
     */
    @Override
    public void init () {


        // Initialize the motors. The motor names you see here are defined using the FTC Robot
        // Controller app, when you create a robot configuration.
        ri1w_drive_left = hardwareMap.dcMotor.get("motor_1");
        ri1w_drive_right = hardwareMap.dcMotor.get("motor_2");

        // Set the right drive train to be reversed.
        ri1w_drive_right.setDirection(DcMotor.Direction.REVERSE);
    }


    /* start() runs as soon as you press the play button in the FTC Driver Station app.
     *
     * This method is not required - if you have nothing to do at the start, you can leave it out.
     * Think of it like the first loop of your program.
     */
    @Override
    public void start () {
        // We don't have anything to do here.
    }


    /* loop() is called repeatedly during the OpMode's execution.
     *
     * This method runs about 180 times per second. The majority of your code will probably be
     * here. This method is required - if you do not have it, the OpMode cannot be run.
     */
    @Override
    public void loop () {

        // Get the current joystick values from the controller. The gamepad{1,2} variables are
        // predefined for you. See the ftc_app Javadocs for more information about the methods
        // you can call on the gamepad.

        left_drive = gamepad1.left_stick_y;
        right_drive = gamepad1.right_stick_y;

        // Also get some information about the buttons on the gamepad. We'll use these to set the
        // boolean variable scale_down.

        if (gamepad1.x)
            scale_down = true;

        if (gamepad1.y)
            scale_down = false;

        // If we wish to scale down the motor speed, do that now.

        if (scale_down) {
            left_drive /= 1.5;
            right_drive /= 1.5;
        }

        // Set the drive train motor speed for this iteration.

        ri1w_drive_left.setPower(left_drive);
        ri1w_drive_right.setPower(right_drive);
    }


    /* stop() is called just before the robot is stopped by the FTC Driver Station app.
     *
     * This method is not required, but you may wish to make sure your motors are stopped.
     */
    @Override
    public void stop () {

        // Stop the motors!

        ri1w_drive_left.setPower(0.0);
        ri1w_drive_right.setPower(0.0);
    }
}