pxt-ev3/docs/labview.md

Coding in MakeCode

This guide is intended for users who are used to the LabView LEGO Minstorms editor.

Snap the blocks

Just like LabView, blocks can be dragged from the cabinet and snapped together to create a sequence of program instructions.

The program below starts, turns on motor A, waits a second and stop motor A.

The blocks are similar: they snap on the ||on start|| block then latch to each other vertically.

motors.largeA.setSpeed(50)
loops.pause(1000)
motors.largeA.stop()

All block programs can be converted to JavaScript and edited from there as well.

motors.largeA.setSpeed(50)
loops.pause(1000)
motors.largeA.stop()

Download to the EV3

The MakeCode editor provides a simulator to try out the code in your browser. It restarts automatically after you make a code change. Once you are ready to transfer it to the @boardname@, click the ||Download|| button and follow the instructions.

Single motors

The program below controls a large motor on port A in a variety of ways: setting the speed, setting the speed for a given time, angle or number of rotations.

motors.largeA.setSpeed(50);
motors.largeA.setSpeed(50, 1000, MoveUnit.MilliSeconds);
motors.largeA.setSpeed(50, 360, MoveUnit.Degrees);
motors.largeA.setSpeed(50, 1, MoveUnit.Rotations);
motors.largeA.stop();

Steering

The steering blocks allow to synchronize two motors at a precise rate. They can also specify the duration, angle or number of rotations.

motors.largeBC.steer(0, 50);
motors.largeBC.steer(0, 50, 1000, MoveUnit.MilliSeconds);
motors.largeBC.steer(0, 50, 360, MoveUnit.Degrees);
motors.largeBC.steer(0, 50, 1, MoveUnit.Rotations);
motors.largeBC.stop();

Tank

The tank blocks control the speed of two motors, typically from a differential drive robot. They can also specify the duration, angle or number of rotations.

motors.largeBC.tank(50, 50);
motors.largeBC.tank(50, 50, 1000, MoveUnit.MilliSeconds);
motors.largeBC.tank(50, 50, 360, MoveUnit.Degrees);
motors.largeBC.tank(50, 50, 1, MoveUnit.Rotations);
motors.largeBC.stop();

Coasting and braking

By default, all motors coast when the move command is done. You can change this behavior with the `set brake`` block.

motors.largeD.setBrake(true);
motors.largeD.setSpeed(50, 1, MoveUnit.Rotations)

Inverting and regulating motors

Sometime you need to invert the direction of a motor. Use the set invert block.

motors.largeA.setInverted(true);

By default, the speed of motors is regulated. This means that if your robot goes up a hill, the regulator will adjust the power to match the desired speed. You can disable this feature using set regulated.

motors.largeA.setRegulated(false);

Brick

The brick category contains a number of blocks to display graphics on the brick screen.

brick.clearScreen()
brick.showImage(images.expressionsWink)

brick.setStatusLight(StatusLight.Off);
brick.setStatusLight(StatusLight.Red);
brick.setStatusLight(StatusLight.OrangePulse);

Waiting (pausing)

It is quite common to wait for a sensor state, such as a touch button pressed. The pause until blocks provide a variety of ways to acheive this.

motors.largeD.setSpeed(50)
loops.pause(1000)
motors.largeD.stop();

motors.largeD.setSpeed(50)
sensors.touch1.pauseUntil(ButtonEvent.Pressed)
motors.largeD.stop();

motors.largeD.setSpeed(50)
sensors.ultrasonic4.pauseUntil(UltrasonicSensorEvent.ObjectNear)
motors.largeD.stop();

You can also use the pause until block to wait on any boolean expression. The runtime will evaluate this expression until it becomes true.

motors.largeD.setSpeed(50)
pauseUntil(() => sensors.touch1.isPressed())
motors.largeD.stop()

Loops

loops.forever(() => {
    motors.largeD.setSpeed(50, 1, MoveUnit.Rotations);
    motors.largeD.setSpeed(-50, 1, MoveUnit.Rotations);
})

for(let i = 0; i < 10; i++) {
    motors.largeD.setSpeed(50, 1, MoveUnit.Rotations);
    motors.largeD.setSpeed(-50, 1, MoveUnit.Rotations);
}
let k = 0;
while(k < 10) {
    motors.largeD.setSpeed(50, 1, MoveUnit.Rotations);
    motors.largeD.setSpeed(-50, 1, MoveUnit.Rotations);    
    k++;
}

Variables

let light = 0;
loops.forever(function () {
    light = sensors.color3.light(LightIntensityMode.Reflected);
    motors.largeD.setSpeed(light)
})

Concurrent loops

You can spin up multiple forever loops that will run at the same time. Only one code is running at the time, but each loop iteration will interleave.

loops.forever(() => {
    motors.largeD.setSpeed(50, 1, MoveUnit.Rotations);
    motors.largeD.setSpeed(-50, 1, MoveUnit.Rotations);
})
loops.forever(() => {
    brick.showImage(images.eyesMiddleRight)
    loops.pause(1000)
    brick.showImage(images.eyesMiddleLeft)
    loops.pause(1000)
})

Conditional

The if block allow to run different code based on a boolean condition. This is similar to the switch block.

loops.forever(function() {
    if(sensors.touch1.isPressed()) {
        motors.largeD.setSpeed(50)
    } else {
        motors.largeD.stop()
    }
})

Random

The random range blocks returns number between two bounds.

loops.forever(function () {
    motors.largeBC.steer(Math.randomRange(-5, 5), 50)
    loops.pause(100)
})