This is a modified version of the official dabit-industries/turtlebot3_blockly repository, which again is a fork of the private aravindk2604/turtlebot3_blockly repo, which was based on the erlerobot/robot_blockly repo. There are two changes. Some modifications in the frontend/blockly submodule, so that the 'seconds' parameter (how long a block should run) is correctly used. Another modification is that this code is tested on a ROS Melodic system - Ubuntu 18.04, with improved documentation.
You can now control TurtleBot3 using Blockly - drag and drop software developed by Google.
python2.7 -m pip install --upgrade pip
python2.7 -m pip install autobahn
python2.7 -m pip install MAVProxy
python3.6 -m pip install cryptography==36.0.2 autobahn
sudo apt-get install curl gnupg2 lsb-release
sudo sh -c 'echo "deb http://packages.ros.org/ros/ubuntu $(lsb_release -sc) main" > /etc/apt/sources.list.d/ros-latest.list'
curl -s https://raw.githubusercontent.com/ros/rosdistro/master/ros.asc | sudo apt-key add -
sudo apt-get install ros-melodic-catkin
sudo apt-get install ros-melodic-mavros ros-melodic-mavros-extras
sudo apt-get install ros-melodic-turtlebot3-teleop
mkdir -p ~/blockly_ws/src
cd ~/blockly_ws/src
git clone https://github.com/physar/turtlebot3_blockly.git
cd ~/blockly_ws/
source /opt/ros/melodic/setup.bash
catkin_make_isolated -j2 --pkg turtlebot3_blockly --install
cd ~/blockly_ws
source install_isolated/setup.bash
roslaunch turtlebot3_blockly turtlebot3_blockly.launch
Open your browser to access the now locally running blockly-webserver: http://127.0.0.1:1036/
If the webserver is up and running, the top-left item under 'Builder' should read 'Launch'. Don't forget to switch the Python radio-button to Python2, because that is the version still used by ROS Melodic.