Frequent Asked Question...

Tbot custom topic types (beep, buttom, etc.)

I cannot echo topics provided by the tbot such /events/button or /events/bumper because the type isn't recognized.

To install those custom types:

cd $ROS_WORKSPACE
git clone https://github.com/imt-mobisyst/pkg-interfaces.git
colcon build --base-path pkg-interfaces
source ./install/setup.bash

Example of Marker publishing (4 spheres)

from visualization_msgs.msg import Marker
from std_msgs.msg import ColorRGBA

[...]

def publish_markers(self):
    # List of marker positions, for example
    marker_positions = [
        (1.0, 2.0, 0.5),
        (2.0, 1.0, 0.5),
        (0.0, -2.0, 1.0),
        (-1.5, -1.5, 0.5)
    ]

    # Loop over the positions to create markers
    for idx, (x, y, z) in enumerate(marker_positions):
        marker = Marker()
        marker.header.frame_id = "map"  # Frame of reference (use 'map' or other valid frame)
        marker.header.stamp = myROSNode.get_clock().now().to_msg()
        marker.ns = "array_of_markers"
        marker.id = idx  # Unique ID for each marker in the array
        marker.type = Marker.SPHERE
        marker.action = Marker.ADD

        # Set the position of each marker
        marker.pose.position.x = x
        marker.pose.position.y = y
        marker.pose.position.z = z
        marker.pose.orientation.w = 1.0

        # Set the scale of the marker (size)
        marker.scale.x = 0.5
        marker.scale.y = 0.5
        marker.scale.z = 0.5

        # Set the color of the marker (green)
        marker.color = ColorRGBA(r=0.0, g=1.0, b=0.0, a=1.0)

        # Publish the marker
        self.my_marker_publisher.publish(marker)

        # Log to confirm marker publishing
        myROSNode.get_logger().info(f"Publishing marker {idx} at position: ({x}, {y}, {z})")

ROS2 tbot driver

How to get ROS2 tbot driver on my computer (to use it without a Pi)

Install:

cd $ROS_WORKSPACE
git clone https://github.com/imt-mobisyst/pkg-interfaces.git
git clone https://github.com/imt-mobisyst/pkg-tbot.git

./script/install-kobuki_ros.sh

colcon build

Launch:

# base only
ros2 launch tbot_start base.launch.py

# base + laser
ros2 launch tbot_start minimal.launch.py

# base + with laser + camera
ros2 launch tbot_start full.launch.py

ros2 topic list

Fix malformed packets

Info there: https://github.com/kobuki-base/kobuki_core/commit/2bc11a1bf0ff364b37eb812a404f124dae9c0699

sudo cp /home/bot/ros2_ws/pkg-kobuki/kobuki_core/60-kobuki.rules /lib/udev/rules.d/

Then unplug / replug the robot. To ensure it worked, the followwing command should display 1:

cat /sys/bus/usb-serial/devices/ttyUSB0/tty/ttyUSB0/device/latency_timer

-->

There is no Wifi on my dell-xps13 ?

Connect with cable
Get the appropriate drivers: killer driver

sudo add-apt-repository ppa:canonical-hwe-team/ backport-iwlwifi
sudo apt-get update
sudo apt-get install backport-iwlwifi-dkms

reboot

Remove password asking for docker commands

sudo echo "\n%sudo   ALL=(ALL) NOPASSWD: /usr/bin/docker\n" >> /etc/sudoers

Catkin_create_pkg - invalid email ?

you can use the -m option to force an author name.

catin_create_pkg -m AuthorName package_name [dependencies...]

`opencv_createsamples`

The latest OpenCV does not include opencv_createsamples. Let's compile an older version (~5 min on labs PC).

git clone https://github.com/opencv/opencv.git
cd opencv
git checkout 3.4.17
mkdir build
cd build
cmake -D'CMAKE_BUILD_TYPE=RELEASE' ..
make -j8

ls -l bin/opencv_createsamples

How to get an aligned depth image to the color image ?

you can use the align_depth:=true ROS parameter. The aligned image is streamed in a specific topic. (tks Orange group)

roslaunch realsense2_camera rs_camera.launch align_depth:=true

ROS1 vs ROS2 commands cheatsheet

ROS1	ROS2
`rostopic list`	`ros2 topic list`
`rqt_graph`	`rqt_graph`
`rviz`	`rviz2`
`rosrun tf view_frames`	`ros2 run tf2_tools view_frames`
	`colcon build --packages-select my_package`
	`colcon build --symlink-install`
	`colcon build --paths path/to/some/package other/path/to/other/packages/*`
	`colcon build --event-handlers console_direct+ --cmake-args -DCMAKE_VERBOSE_MAKEFILE=ON --packages-select my_package`

`.bashrc` ROS additions

# ROS
export ROS_LOCALHOST_ONLY=1
export PS1="\${ROS_VERSION:+(ros\$ROS_VERSION) }$PS1"
alias rosify1="source /opt/ros/noetic/setup.bash && source $HOME/ros1_ws/devel/setup.bash"
alias rosify2="source /opt/ros/iron/setup.bash && source $HOME/ros2_ws/install/setup.bash"

Flash kobuki

https://kobuki.readthedocs.io/en/devel/firmware.html#linux

ROS2 Package with custom Python Library

suppose we are in packge my-package
Inside the package folder my-package create a folder for my library. For example libs/my_lib
Inside myLib folder add __init__.py file that imports resources from other python files.
Add the CMakeList.txt

install( DIRECTORY libs/my_lib DESTINATION lib/${PROJECT_NAME})

build the package colcon build