pxt-ev3/docs/getting-started/use.md

Use

[IMG: EV3 Driving Base full w/cuboid]

Build a robot and drive into the world of robotics! In this project we will guide you through building a Driving Base Robot and programming it to move straight and turn. You will also build and Object Detector Module, and program it to detect an object. It’s a good idea to have done the Try sequence first.

Connect

[IMG: Apple Picker]

What if your school had a multipurpose robot? How would you use it?

Would you use it to clean the school or plant trees?

Build Your Driving Base Robot

[IMG: EV3 Driving Base Building Instructions Cover Image]

• Building instructions

Make It Move

[IMG: Program Blocks (see JavaScript below)]

1. Create a program that makes the Driving Base move forward and stop at the finish line, which is 1 meter away.

Start by building this program:

brick.buttonEnter.onEvent(ButtonEvent.Pressed, function () {
    motors.largeBC.steer(0, 50, 1, MoveUnit.Rotations)
})

• Drag a steer large B+C motor block inside the on button block
• Click on the + sign
• Change to 1 rotation

~ hint

Hint: You will have to modify the number of rotations until you find the number that matches the robot moving forward 1 meter and stopping.

~

2. Click Download and follow the instructions to get your code onto your EV3 Brick. Press the center button on the EV3 Brick to run the program.

Make It Turn

[IMG: Program Blocks (see JavaScript below)]

brick.buttonEnter.onEvent(ButtonEvent.Pressed, function () {
    motors.largeBC.steer(-50, 50, 1, MoveUnit.Rotations)
})

1. Create a new program that turns the Driving Base 180 degrees.

~ hint

Hint: You will have to modify the turn ratio and the number of rotations until the robot reaches 180 degrees.

~

2. Click Download and follow the instructions to get your code onto your EV3 Brick. Press the center button on the EV3 Brick to run the program.

Add an Ultrasonic Sensor to Your Driving Base

[IMG: EV3 Ultrasonic Sensor Driving Base Building Instructions Main Image]

• building instructions

Detect an Object

[IMG: Program Blocks (see JavaScript below)]

1 - Create a program that moves the Driving Base and makes it stop 6 cm from the Cuboid.

Create a new program

brick.buttonEnter.onEvent(ButtonEvent.Pressed, function () {
    motors.largeBC.tank(50, 50)
    sensors.ultrasonic4.setThreshold(UltrasonicSensorEvent.ObjectDetected, 6)
    sensors.ultrasonic4.pauseUntil(UltrasonicSensorEvent.ObjectDetected);
    motors.stopAll()
})

• Drag a tank large B+C motor block inside the on button block
• Drag a threshold Ultrasonic Sensor block and place below the motor block
• Drag a stop all motors block and place it below the sensor block

~ hint

Hint: You will have to modify the values of the Ultrasonic Sensor block until the robot reaches the desired position.

~

2. Click Download and follow the instructions to get your code onto your EV3 Brick. Press the center button on the EV3 Brick to run the program.

Click on the JavaScript tab and change and test the number value of the Ultrasonic Sensor

sensors.ultrasonic4.setThreshold(UltrasonicSensorEvent.ObjectDetected, 10)

[IMG: EV3 Ultrasonic Sensor Driving Base Building Instructions Main Image]

Congratulations!

You are ready to move on to the next steps. Try a LEGO MINDSTORMS Design Engineering, Coding, or Maker activity.