UUV_softPi

ROS2 shell and software for UUV's Raspberry Pi

Software

Setting up Raspberry PI ● Do not use Ubuntu Core, Use Ubuntu Desktop. The current OS is Ubuntu 22.04.1 LTS with Desktop Image ● To install miniconda use Miniconda3-py39_4.9.2-Linux-aarch64.sh . DO NOT UPDATE Conda version ● Install ROS2 HUMBLE on Ubuntu Deskop 22.0.4. Instructions here ○ Install Desktop, not BareBones or Development Tools Install USB V4L Camera Driver for Dell Camera

Required Libraries

• Colcon
• Github
• v4l2loopback
• ROS2 Desktop (Humble)

● Instructions to install USB V4L Camera Driver for Dell Camera ○ Before following instructions install the following: ■ Install Colcon. sudo apt install python3-colcon-common-extensions ■ Install git hub: sudo apt install git ○ Prepare Termainal by Exceucting in the Command Line: source /opt/ros/humble/setup.bash to start ROS2 in Ubuntu terminal ○ Use Quickstart:
sudo apt install ros-humble-usb-cam ● Install v4l2loopback ○ This is to initialize /dev/video0, which is required to run the camera in an image viewer. If the raspberry pi does not recognize the camera through this input, it will not work in ROS2 ● Restart Raspberry Pi4. Turn power off. Plug camera in to correct bus as shown in step below. Turn power on. ● Plug Camera USB to BUS 2 USB. Only recognizes video 0 on Bus 002 of the Raspberry Pi. Camera must be connected to BUS 2 and no other bus. Use the command lsusb to verify connectivity and that it is connected to the right bus. The camera will be labeled as DELL. Camera must be recongized for the next step to work ● Open terminal and execute: source /opt/ros/humble/setup.bash *when opening new terminal window you must always execute source /opt/ros/humble/setup.bash to start ROS2 in Ubuntu terminal ● To view image use code below. A live stream of the camera will appear as well as show that the specifications of the image on the terminal. Press CTRL+C to exit ros2 launch usb_cam demo_launch.py   Install IMU DRIVER On ROS2

Bugs

Bugs: Currently there is a bug in the code where the SMBus is not being read in my_python_node.py I am not sure why this is happening if I2C is enabled and SMBus library is added. This happens when you execute the IMU ROS2 node

Required Libraries

• python 3.7 (the version is important!)
• raspi-config
• I2c-tools
• setuptools==58.2.0 (the version is important!)
• smbus

install python 3.7 or less (setuptools will not work if running on higher python)

$ sudo apt install python3.7

install raspi-config to configure I2C

$ sudo apt-get update $ sudo apt-get install raspi-config

Enable I2C by opening Raspberry Pi configuration tool using the code below to open this tool

$ sudo raspi-config

Install I2C tools to see if IMU is detected

$ sudo apt install i2c-tools

Install setup tools to run node

$ pip install setuptools==58.2.0

Install smbus

$ pip install smbus

The following instructions are to initialize a ros2 node. Code should be already properly zipped in the Github. The code in the GitHub file should be saved in Desktop. However, if you need to create a ros 2 node here are the instructions to do so. Use this website for help. Reminder that

##The code below sets up the main folder for node and the src folder inside the main folder $ cd ~/ros2_ws/src

Initialize ros 2 node package

$ ros2 pkg create my_robot_tutorials --build-type ament_python

Go to my_robot_tutorials folder which was created when you built the package. Create a new python file called my_python_node.py

$ cd my_robot_tutorials/my_robot_tutorials $ touch my_python_node.py

Open the setup.py file. Edit the python file at the line that says entry_points. Edit the line so it to looks like the code below declaring the name of the node action.

entry_points={ 'console_scripts': [ 'minimal_python_node = my_robot_tutorials.my_python_node:main' ], ...

Open the package.xml file. Edit the python file to include the license name shown below:

Apache-2.0

In the package.xml file add the following two lines in the order shown here. They will be included above the other depend code lines.

rclpy <buildtool_depend>ament_python</buildtool_depend>

Go back to terminal and run code below to compile package in ros2_ws . You will need to do this anytime there are any changes to the ros2_ws folder and the python codes inside

$ cd ros2_ws $ colcon build --packages-select my_robot_tutorials

The remaining steps below are to implement the ROS2 node for the IMU. It will go over how to recompile the package if necessary.

Run the following code to check IMU connection. The output should look like the image below or else there may be problems with your IMU connection:

$ sudo i2cdetect -y 1

Recompile Code in terminal (if necessary)

$ cd ros2_ws $ colcon build --packages-select my_robot_tutorials

Open new terminal window and execute ros2 node. :

$ source /opt/ros/humble/setup.bash $. ~/ros2_ws/install/setup.bash $ ros2 run my_robot_tutorials minimal_python_node ***Currently there is a bug in the code where the SMBus is not being read in my_python_node.py I am not sure why this is happening if I2C is enabled and SMBus library is added.