State Machines

A state machine is a way to organize a program by dividing behavior into different states.

Instead of writing one long sequence of instructions, the robot is always in a specific state and decides when to transition.

For example:

enum State {
    INTAKING,
    DRIVING,
    SHOOTING,
    PARKED
}

The robot might follow this flow:

DRIVING
   ↓
Target found
   ↓
SHOOTING
   ↓
Finished scoring
   ↓
PARKED

Why Use State Machines?

State machines solve many problems with sequential code.

They allow robots to:

• Pause and resume actions
• React to sensors
• Handle unexpected situations
• Manage complex autonomous routines

Instead of:

drive();
shoot();
park();

You can think:

If driving is complete:
    switch to shooting

If shooting is complete:
    switch to parking

FTC Examples

State machines are commonly used for:

Autonomous routines

START
 ↓
MOVE_TO_GOAL
 ↓
SCORE
 ↓
PARK

Mechanisms

IDLE
 ↓
INTAKE_ACTIVE
 ↓
GAME_PIECE_DETECTED
 ↓
READY_TO_SCORE

State Machine Libraries

While you can build a state machine yourself using enums and switch statements, many teams choose to use a library that simplifies the process.

One popular option is StateFactory, which provides a structured way to define states and transitions without writing all of the boilerplate yourself.

State machines are one of the first major steps toward writing scalable robot software.