The FTC SDK, Programming Tools and Robot Configuration

The FTC SDK (Software Development Kit) is the official software from FIRST that every team builds on. It contains the Robot Controller app that runs on the Control Hub, the libraries for motors, servos and sensors, and many sample OpModes. Your programs, called OpModes, become part of the Robot Controller app. The Driver Station app runs on the Driver Hub or phone: it lets drivers pick an OpMode, start and stop it, sends gamepad input to the robot and shows messages from the robot.

Follow the path of one action. A driver pushes a joystick. The Driver Station reads the gamepad and sends the values over Wi-Fi. Your OpMode on the Control Hub reads gamepad1, calculates a power, and calls setPower. The Control Hub sends that power to a motor port, and the wheel turns. Messages you send with telemetry travel back the same way to the Driver Station screen. The 12 V battery powers everything on the robot through the main power switch.

Three ways to program

To open Blocks or OnBot Java, connect your laptop to the Control Hub's Wi-Fi network and open the Robot Controller Console in a browser at 192.168.43.1:8080. A good path for a new team is to start in OnBot Java, because the code is exactly the Java you will later use in Android Studio. Blocks is a fine choice if your programmers have never typed code before: the ideas (variables, loops, hardwareMap, gamepad) are identical. This module shows Java.

Robot configuration: telling the hub what is plugged in

The Control Hub cannot see what kind of device is on each port or what you want to call it. A robot configuration is a saved list that says: 'on motor port 0 there is this type of motor, and its name is left_front'. Your code then asks for devices by those names. You can store several configurations, but only the active one is used.

1. 1
   Connect

   Power on the robot and make sure the Driver Station shows it is connected to the Control Hub.
2. 2
   Open the menu

   On the Driver Station, open the menu (three dots) and choose Configure Robot, then New.
3. 3
   Select the hub

   Choose the Control Hub Portal, then the Control Hub (and the Expansion Hub, if you have one).
4. 4
   Add motors

   Open Motors, choose the matching motor type for each used port, and type a name for each one.
5. 5
   Add servos and sensors

   Open Servos and set the type (Servo or Continuous Rotation Servo) and a name. Add sensors on the I2C or digital ports the same way.
6. 6
   Save and activate

   Press Done until asked to save, give the configuration a clear name, and make sure it is shown as the active configuration.

Hardware mapping: names must match exactly

In code, the hardwareMap object gives you devices from the active configuration. You tell it the device class and the configuration name. Java then gives you an object you can control. The name in quotes must match the configuration character for character, including capital letters, underscores and spaces.

1// Inside runOpMode(), before waitForStart()
2DcMotor leftFront  = hardwareMap.get(DcMotor.class, "left_front");
3DcMotor rightFront = hardwareMap.get(DcMotor.class, "right_front");
4Servo claw         = hardwareMap.get(Servo.class, "claw");
5
6// Needed imports at the top of the file:
7// import com.qualcomm.robotcore.hardware.DcMotor;
8// import com.qualcomm.robotcore.hardware.Servo;

• Use short, lowercase names with underscores, such as left_front or arm_motor.
• Describe position or job, not the port number, so the name still makes sense if you move a cable.
• Put a label on each cable and port so the wiring matches the configuration.
• Write the full configuration table in your engineering portfolio and on the team whiteboard.