CCW Cohort Teachers, click on the link below to access editable worksheets and presentation slides.

How to connect Lego Mindstorms EV3 to Open Roberta

(IMPORTANT: If you are lending the EV3 robots from SEP, you will not need to do this procedure. Robots borrowed from SEP are already set up to run Open Roberta. Use this procedure only if you are purchasing your own EV3 robots, or using robots that already exist at your school site, and would like to use Open Roberta.)

Required Materials

  • Device with an internet connection (iPad,Chromebook, laptop, desktop computer, etc.)
  • WiFi dongle (1 per EV3 robot plugged into USB port)
    • Recommended: Edimax EW-7811Un 150Mbps 11n Wi-Fi USB Adapter
  • MicroSD card (1 per EV3 robot plugged into SD port)
    • Recommended: SanDisk 4GB MicroSDHC Memory Card with SD Adapter
  • An SD card reader that fits in your computer (most computers/laptops have a card reader built in on the side)
  • WiFi router (one per classroom or set of robots)

Please note: EV3s will not connect to internet that require a login ID. The internet must require a password, but no login ID.

The following three-step procedure (preparing the micro SD card, installing Lejos, and connecting the EV3 to the WiFi) must be completed for each EV3 robot. If you are having trouble with any of the following steps, please contact Jessica Allen at jessica.allen@ucsf.edu.

Step 1: Preparing the micro SD Card

To connect the Lego Mindstorm EV3 to Open Roberta, you must first download a program called Lejos on the each EV3. This is done by downloading Lejos onto a microSD card and creating what’s called a “bootable SD card.”

  1. Format your microSD cards to FAT32 (note: Formatting on macs may require an additional program download.)
      • Put your micro SD card into the SD card adapter, then the adapter into the card reader of your computer. Connect the card reader to your computer.
      • Click control “get info” to check the format. (If the sd card is already FAT32 skip to the next step).
      • Click format in the drop-down menu
      • Select “FAT32” as the file system and format
  2. Add the Lejos files to the formatted microSD card to make a “bootable SD card”.
      • Download the zip file from https://ucsf.box.com/v/lejos.
      • Add all the files found inside the zip file to your micro SD card (You must unzip the folder before loading all the files on to your SD card. Do not unzip ejre-7u60-fcs-b19-linux-arm-sflt-headless-07_may_2014.gz).

      • Check that the files on your micro SD card match with those shown in the image.
      • Finally, remove the micro SD card adapter (safely) from your computer and then take out the micro SD card.

Step 2: Installing Lejos on the Lego Mindstorm EV3

Now that you have created a “bootable SD card”, you will need to insert this SD card into the Lego Mindstorms EV3. Note that if you ever want to uninstall Lejos from your EV3, simply remove the micro SD card and reboot the robot.

  1. Make sure that the EV3 robot is switched off
  2. Insert the micro SD card into your robot EV3 (there is a port labeled SD on one side).
  3. If you wish to connect your robot using a wireless network while operating the Open Lab Roberta in step 3 (below), we recommend that you insert the WiFi USB Adapter into the side USB port of your robot EV3.
  4. Now, start the EV3 robot by pressing the center dark gray button.
  5. The operating system will be installed automatically in the next 8 minutes and restart. You will know that the installation is complete when you hear a short melody. You should now see the main menu on the screen of your robot (see below).

After the operating system is installed on your EV3 robot subsequent starts will start faster.Normally the robot is ready for use 1-2 minutes after switching on.

If you do not see the main menu screen (above), but instead see the normal Lego Mindstorm menu, the SD card is likely formatted incorrectly. Contact Jessica at jessica.allen@ucsf.edu for help. See a video of the installation process here.

(To uninstall Lejos from a Lego robot, simply remove the micro SD card from the SD card slot.  The robot will return to its factory settings.)

Step 3: Connect your EV3 to the WiFi

We recommend maintaining a dedicated WiFi router for EV3s using Lejos and Open Roberta. This will save you time as you will not need to reset the WiFi each time you use the EV3’s. Please note that the programming device (computer, laptop, iPad, etc.) does not need to be connected to the same WiFi network to connect to the EV3s with Open Roberta. It is recommended to have students connect to Open Robert a using a firewalled school internet while the EV3s are connected via a dedicated WiFi router.

(Don’t have access to wifi? Wifi down? Connection issues? No problem! See the links at the bottom of this page.)

1. Set up your dedicated WiFi router so that it has a password.
2. Navigate to the WiFi menu on your EV3 robot (the navigation is done with the left / right buttons on the EV3-brick)

3. When you find the WiFi menu, select it by clicking on the dark gray (Enter) button.
4. Now choose the name of your WiFi network with the up/down buttons on the EV3 brick and click again on the Enter button (In the example below, “roberta” is the only available WiFi network).

5. Enter the password using the on-screen keyboard on your EV3 robot.

          • Uppercase letters can be selected with the “U” and lowercase letters can be selected with the “l”
          • Use the “x” to delete the previous letter
          • The bottom line shows which letters you have already entered
          • To confirm the password, you need to select the “D”

6. If a connection is successfully made the EV3 brick will return to the main menu with a second IP address (third row from the top, the numbers are likely to be different), and a WiFi icon will appear on the top right. The EV3 will retain this WiFi configuration until you enter a new configuration. Therefore, each time you switch on the EV3, you will not need to re-enter the WiFi information.

Can’t connect via wifi? Connect via USB using the following instructions depending on your device:

Open Roberta USB App for Desktop (Windows, Linux, MacOS)

Open Roberta USB Chrome App Instructions

Open Roberta App for iPhone/iPad (connect via Bluetooth)