How it all fits together

For: students who have written a TeleOp and want the big picture. You need: nothing to install; the first lessons help.

One page to see the whole library, and where your team’s code goes. TeamCode is the folder in your robot project where your team’s own code lives.

The layers

flowchart TB
    subgraph TEAM["TeamCode (your team, changes every season)"]
        RS["RobotSettings (RobotConfig)<br/>names, numbers"]
        RB["Robot<br/>your mechanisms"]
        TO["MainTeleOp (EasyTeleOp)<br/>buttons -> actions"]
        AU["Autos (EasyAuto)<br/>lists of steps"]
    end
    subgraph LIB["ftc-helper-lib (stays the same across seasons)"]
        direction TB
        R["robot: RobotDefinition, the modules (Intake, Lift, Claw, Launcher...),<br/>ControlMap, Action, Auto + Steps"]
        A["teleop + auto: EasyTeleOp, EasyAuto, AutoRoutine, AutoStep"]
        M["mechanism + launcher + vision<br/>PositionMotor, SpinMotor, servos, Flywheel, Turret, Launcher, cameras"]
        D["drive: MecanumDrive, TankDrive, DriverControls, DriverHeading, AutoDrive"]
        FI["finders + testing: Servo/Motor/Flywheel finders, Drive/Shot/Aim tuners, Hardware Check"]
        G["gamepad + match + tuning + telemetry<br/>ControllerBindings, InitMenu, MatchTimer, Tunable, RobotTelemetry"]
        C["core + control + safety + hardware + util<br/>Subsystem, Profile, RobotConfig, PidController, SafeMotor, MotorSetup, MathUtil"]
    end
    SDK["FTC SDK (FIRST, new version each season)"]
    TEAM --> LIB --> SDK

The five-files way (robot module) sits on top: the team’s Robot.java, Tunables.java, Controls.java, Actions.java and autos use the robot package (a package is a folder of classes that belong together), which builds the same mechanism, drive, teleop and auto parts underneath. Both ways work; a team can mix them (a module’s part() gives the plain part inside).

Rule of thumb: if it is true for any game, it goes in the library. If it is about THIS game (field positions, which tag, how many pieces, scoring heights), it goes in TeamCode.

One loop, every loop

Every TeleOp has the same shape, whatever the robot:

flowchart LR
    R["read the gamepads<br/>controls.update()"] --> C["commands<br/>(quick: set targets and modes)"]
    C --> U["update every mechanism<br/>robot.all.update()"]
    U --> T["telemetry<br/>t.update()"]
    T --> R

• Commands are quick. A button sets a target (“lift to HIGH”). It never waits.
• update() does the work, once per loop: PID (the math that moves a motor to a target and holds it there), limits, jam checks, timing.
• No sleep() in TeleOp. While the code sleeps, the robot cannot react. Full guide: Non-blocking code. Only autonomous moves and steps block, on purpose.

EasyTeleOp runs this loop for you in TeleOp. In autonomous, AutoRoutine runs the same update() for you during every move and wait. The exact order, what each part reads and writes on the hub, when files are written and what stays between OpMode runs: what runs every loop.

You do not have to take all of it: every building block (buttons, SafeMotor, PositionMotor, PidController, bulk reads, timers, the finders) works alone in your own LinearOpMode. See use only what you need.

The interfaces (where new things plug in)

An interface is a short list of methods a class promises to have. Any class that has them can plug in.

Interface	Ready-made	Write your own when…
Subsystem	every mechanism helper	you build a new kind of mechanism
AutoStep	goToStep, shootStep, runForStep…	a step needs custom logic
Feeder	MotorFeeder, ServoFeeder	the launcher is fed a new way
TargetSource	WebcamTags, LimelightTags	a new camera or a new kind of target

See Extending the library.

Where each kind of number lives

Number	Lives in	Changed by
motor names, directions, gear ratios	TeamCode RobotSettings / Robot (five files: Robot.java)	code
every module’s numbers (five files)	TeamCode Tunables.java, one section per part	tuning menu, then copied into the file (INIT lists the lines)
PID gains, positions, shot table	TeamCode, made tunable(...) while tuning	tuning menu, then copied into code
practice vs competition values	Profile.pick(a, b)	the INIT menu’s profile line
match choices (alliance, delay, route)	InitMenu	the drivers, in INIT