pxt-ev3/docs/reference/control/run-in-parallel.md

@extends

Separate tasks #tasks

As an example, you could have a small task that checks the battery level and gives a warning when it drops below 15 percent. This is placed inside a ||control:run in parallel|| block:

let powerCheck = false;

control.runInParallel(() => {
    while (!powerCheck) {
        if (brick.batteryLevel() <= 15) {
            brick.setStatusLight(StatusLight.RedFlash)
            powerCheck = true;
        } else {
            pause(5000);
        }
    }
})

The code the main program just drives the brick in a constant pattern until the battery check in the parallel task says that the battery level is too low.

let powerCheck = false;
while (!powerCheck) {
    motors.largeBC.tank(50, 50, 5, MoveUnit.Seconds)
    motors.largeBC.steer(5, 50, 6, MoveUnit.Rotations)
}
motors.stopAll()

#example

Tank the brick in a pattern until the battery warning variable is set. Have a separate task check the battery level and set a warning variable when the level is below 5 percent.

let powerCheck = false;

control.runInParallel(() => {
    while (!powerCheck) {
        if (brick.batteryLevel() < 5) {
            powerCheck = true;
        } else {
            pause(5000);
        }
    }
})

while (!powerCheck) {
    motors.largeBC.tank(20, 20, 5, MoveUnit.Seconds)
    motors.largeBC.steer(15, 20, 6, MoveUnit.Rotations)
    motors.largeBC.tank(40, 40, 5, MoveUnit.Seconds)
    motors.largeBC.steer(-10, 20, 3, MoveUnit.Rotations)
}
motors.stopAll()

See also #seealso

forever