Creating and running programs¶

Now that you’ve set up your computer and EV3 Brick, you’re ready to start writing programs.

To make it easier to create and manage your programs, let’s first have a quick look at how MicroPython projects and programs for your EV3 robots are organized.

Programs are organized into project folders, as shown in Fig. 7. A project folder is a directory on your computer that contains the main program (main.py) and other optional scripts or files. This project folder and all of its contents will be copied to the EV3 Brick, where the main program will be run.

This page shows you how to create such a project and how to transfer it to the EV3 Brick.

Fig. 7 A project contains a program called main.py and optional resources like sounds or MicroPython modules.¶

Creating a new project¶

To create a new project, open the EV3 MicroPython tab and click create a new project, as shown in Fig. 8. Enter a project name in the text field that appears and press Enter. When prompted, choose a location for this program and confirm by clicking choose folder.

Fig. 8 Creating a new project. This example is called getting_started, but you can choose any name.¶

When you create a new project, it already includes a file called main.py. To see its contents and to modify it, open it from the file browser as shown in Fig. 9. This is where you’ll write your programs.

If you are new to MicroPython programming, we recommend that you keep the existing code in place and add your code to it.

Fig. 9 Opening the default main.py program.¶

Opening an existing project¶

To open a project you created previously, click File and click Open Folder, as shown in Fig. 10. Next, navigate to your previously created project folder and click OK. You can also open your recently used projects using the Open Recent menu option.

Fig. 10 Opening a previously created project.¶

Connecting to the EV3 Brick with Visual Studio Code¶

To be able to transfer your code to the EV3 Brick, you’ll first need to connect the EV3 Brick to your computer with the mini-USB cable and configure the connection with Visual Studio Code. To do so:

Turn the EV3 Brick on
Connect the EV3 Brick to your computer with the mini-USB cable
Configure the USB connection as shown in Fig. 11.

Fig. 11 Configuring the USB connection between the computer and the EV3 Brick¶

Downloading and running a program¶

You can press the F5 key to run the program. Alternatively, you can start it manually by going to the debug tab and clicking the green start arrow, as shown in Fig. 12.

When the program starts, a pop-up toolbar allows you to stop the program if necessary. You can also stop the program at any time using the back button on the EV3 Brick.

If your program produces any output with the print command, this is shown in the output window.

Fig. 12 Running a program¶

Expanding the example program¶

Now that you’ve run the basic code template, you can expand the program to make a motor move. First, attach a Large Motor to Port B on the EV3 Brick, as shown in Fig. 13.

Fig. 13 The EV3 Brick with a Large Motor attached to port B.¶

Next, edit main.py to make it look like this:

#!/usr/bin/env pybricks-micropython

from pybricks import ev3brick as brick
from pybricks.ev3devices import Motor
from pybricks.parameters import Port

# Play a sound.
brick.sound.beep()

# Initialize a motor at port B.
test_motor = Motor(Port.B)

# Run the motor up to 500 degrees per second. To a target angle of 90 degrees.
test_motor.run_target(500, 90)

# Play another beep sound.
# This time with a higher pitch (1000 Hz) and longer duration (500 ms).
brick.sound.beep(1000, 500)

This program makes your robot beep, rotate the motor, and beep again with a higher pitched tone. Run the program to make sure that it works as expected.

Managing files on the EV3 Brick¶

After you’ve downloaded a project to the EV3 Brick, you can run, delete, or back up programs stored on it using the device browser as shown in in Fig. 14.

Fig. 14 Using the EV3 device browser to manage files on your EV3 Brick¶

Running a program without a computer¶

You can run previously downloaded programs directly from the EV3 Brick.

To do so, find the program using the file browser on the EV3 screen and press the center button key to start the program as shown in in Fig. 15.

Fig. 15 Starting a program using the buttons on the EV3 Brick¶