FAQ

Common issues with the Raspberry Pi 4B

1. Access point is not visible

If your Raspberry Pi is in AP mode, a Turtlebot4 WiFi network should become visible about 30 seconds after the robot has been powered on. If it does not, try the following.

Check that the Raspberry Pi is powered

The Raspberry Pi has a Power LED near the USB-C port. Make sure it is illuminated.

If the LED is not on, then the Raspberry Pi is not powered. Check the USB-C connection and make sure the Create® 3 power adapter board is inserted fully.

Check for obstructions

If the Pi is on but you cannot see the access point, make sure that any wires in the robot are not obstructing the WiFi module of the Raspberry Pi. This includes the ribbon cable connecting the RPi to the UI PCBA on the TurtleBot 4, and the wires powering the fans on both models.

RPi 4B WiFi — Raspberry Pi 4B WiFi module and antenna

Restart the robot

If the WiFi module is unobstructed, try restarting the robot. Take the robot off of its dock and press and hold the Power button on the Create® 3 until it is off. Wait a few seconds and place the robot back on its dock.

Access the RPi over Ethernet

If you are still unable to see the Turtlebot4 access point, you can connect directly to the RPi using an ethernet cable. You may need a USB to Ethernet adapter for your PC.

Ethernet connection — Connecting to the TurtleBot 4 over Ethernet

The Raspberry Pi uses a static IP address for the ethernet interface, 192.168.185.3. You will need to configure your wired connection to use the same subnet:

Go to your wired connection settings.
Set your IPv4 Method to Manual and set your static IP. The IP address cannot be the same as the Raspberry Pi.

Setting IP — Configure your PC's wired IP

Click ‘Apply'

You can now go to your terminal and SSH into the robot by typing:

ssh ubuntu@192.168.185.3

If you are still unable to ssh into the robot and receive the error No route to host then this may be the result of the sd card being flashed improperly. This can happen if the image wasn't extracted before flashing or if the image was flashed to a partition on the sd card. Instructions on how to flash the SD card can be found here.

If you are able to ssh into the robot then you can continue the setup instructions to connect the raspberry pi to your network.

2. Waiting to connect to bluetoothd…

This issue is usually a result of the bluetooth service being stopped.

To start the service again, run sudo systemctl start bluetooth.

3. No default controller available

This error occurs if you are attempting to connect a bluetooth device to the Raspberry Pi with sudo bluetoothctl and the hciuart service throws errors.

To fix this, call sudo systemctl disable hciuart and then reboot the Pi with sudo reboot.

Once the Pi has restarted, call sudo systemctl restart hciuart. Now you can run sudo bluetoothctl again and the bluetooth controller should be found.

4. OAKD topics not present

There is an automatic power-saving mode that shuts down the OAKD topics when the robot is docked. Undock your robot.

Common issues with the user PC

1. ros2: command not found

Make sure you have sourced ROS 2 Galactic:
```
source /opt/ros/galactic/setup.bash
```
Make sure you have sourced ROS 2 Humble:
```
source /opt/ros/humble/setup.bash
```

If you are building packages from source, you will also want to source the workspace:

source /path/to/ws/install/setup.bash

2. Create® 3 topics are not visible

First, check that the Create® 3 is connected to your WiFi network. You should be able to access the Create® 3 portal by entering the Create® 3 IP address in a browser. For information on how to connect the Create® 3 to WiFi, check the Wi-Fi Setup Guide.

If it is connected to WiFi, check if you can see Create® 3 topics on the Raspberry Pi.

If topics are visible on the Raspberry Pi, ensure that your PC has the following configuration set for CycloneDDS:

<CycloneDDS>
    <Domain>
        <General>
            <DontRoute>true</DontRoute>
        </General>
    </Domain>
</CycloneDDS> 
  

To set this configuration automatically, add the following line to your ~/.bashrc file.

export CYCLONEDDS_URI='<CycloneDDS><Domain><General><DontRoute>true</></></></>'
  

If you have set a ROS_DOMAIN_ID for the Create® 3, your terminal will have to have the same ID. You can set the ID by using this command:

export ROS_DOMAIN_ID=#
  

Replace # with the ID.

If topics are not visible on the Raspberry Pi, you may need to restart the Create® 3 application through the portal, or reboot the robot.

Replacement Components for the Create® 3

The Turtlebot4 is built ontop of the Create® 3 platform which has components that can be replaced as they wear. These components can be purchased directly from iRobot at the following links.