Lesson 17: Timing

Timing is important because robot code runs many times per second. If you want something to happen for half a second, happen once, or stop after a timeout, you need to think carefully about time.

Do Not Pause the Robot

A common beginner mistake is to use a sleep or delay inside periodic robot code. That stops the rest of your code from running, which means sensors, driver input, and safety checks may not update when you need them.

Avoid blocking delays in periodic code. Store a start time and keep checking whether enough time has passed.

Using a Timer

The pattern is simple: reset a timer when an action starts, then check the timer each cycle.

Timer timer = new Timer();
boolean shooting = false;

public void robotInit() {
    timer.start();
}

public void teleopPeriodic() {
    if (joystick.getRawButton(1) && !shooting) {
        shooting = true;
        timer.reset();
    }

    if (shooting) {
        shooterMotor.set(1.0);

        if (timer.get() > 0.75) {
            shooting = false;
            shooterMotor.set(0.0);
        }
    }
}

Timeouts

Timeouts are safety nets. If an elevator should hit a limit switch in two seconds, stop it if it takes longer than that. A timeout will not fix bad mechanical design, but it can prevent a stalled motor from burning itself up while you debug.

Practice

Write code for an intake that runs for one second after a button press. Then add a second condition that stops early if a sensor says a game piece has been captured.