Skip to content

Installation

This section provides a guide to install and configure the environment required to run the DJI Tello altitude control system on Raspberry Pi 4. It covers dependency installation, ROS 2 Humble setup, and development environment configurations.

1.0 System Requirements

1.1 Hardware Requirements

  • Raspberry Pi 4 (8GB RAM)
  • Storage: 32 GB microSD card (Class 10)
  • DJI Tello Drone

1.2 Software Requirements

  • Operating System: Ubuntu 22.04 LTS (64-bit, ARM)
  • Python: 3.10
  • ROS 2: Humble Hawksbill distribution
  • Additional: Git, pip, Python virtual environment

2.0 Environment Setup

2.1 Update the system

sudo apt update && sudo apt upgrade -y
sudo apt install -y curl wget git python3-pip

2.2 ROS 2 Humble Installation

To install ROS 2 Humble fallow the instructions of the next web page: ROS 2 Humble installation!

2.3 Creating a Python virtual environment

To verify if virtualenv is ready installed, run: 

virtualenv --version
If virtualenv is not installed, run: 
sudo apt update && sudo apt install -y python3-virtualenv
Create a new workspace: 
cd ~
mkdir drone_altitude_ws
open the directory: 
cd drone_altitude_ws
To create the virtual environment, run: 
virtualenv -p python3 ./venv
Activate the virtual environment using the next source command: 
source ./venv/bin/activate
After you activate the environment your command prompt will change to show that you are in a Python virtual environment.

To use a virtual environment with ROS 2 you must tell colcon to ignore the directory that contains the files that manage the virtual environment: 

touch ./venv/COLCON_IGNORE
To exit your virtual virtual environment type: 
deactivate

To ensure your ROS 2 distribution can access Python packages installed in your virtual environment, you need to explicitly add the virtual environment's Python path to ROS's Python system path. This bridges the gap between your isolated Python environment and the ROS 2 ecosystem.

Add the following lines to your virtual environment's activation script to automatically configure the Python path when the environment is activated: 

export PYTHONPATH=${PYTHONPATH}:/path-to-your-env/lib/python3.10/site-packages

Example: Modify Virtual Environment Activation Script

Your virtual environment's path or your python version will differ. Ensure you use the correct path for your venv name and Python version in the following commands

Navigate to your env-package path: 

cd ~/path/to/your/env-package
Use the next command to get the absolute path of your current file: 
pwd

env-package-path environment package path

navigate to your virtual environment activate file: 

cd ~/path/to/your/activate_file
open the activate file using a text editor: 
gedit activate

open-activate-file Open activate file

Add the env-package path to your activate file: 

export PYTHONPATH=${PYTHONPATH}:/path-to-your-env/lib/python3.10/site-packages

edit-activate-file Edit activate file

3.0 Project Cloning and Initialization

clone the repository into your drone_altitude_ws workspace: 

git clone https://github.com/LichtenbergCode/tello-pid-altitude-control-ros2.git
Activate your Python virtual environment: 
source venv/bin/activate
Install the necessary Python modules for the application: 
pip install -r requirements -v
Compile the packages: 
colcon build

Use colcon build only within your drone_altitude_ws workspace

Activate the environment you just compiled: 

source install/setup.bash
Run the app: 
ros2 launch drone_altitude_bringup drone_altitude.launch.xml

4.0 Troubleshooting

4.1 Tello Connection Problems

Issue: Cannot connect ro Tello drone

Check WiFi connection: 

nmcli device wifi list
nmcli connection show
Verify Tello WiFi is available: 
sudo iwlist scan | grep -i tello
Restart network manager: 
sudo systemctl restart NetworkManager

4.2 Module problems

Issue: "ModuleNotFoundError: No module named 'matplotlib.tri.triangulation'"

Uninstall matplotlib in your virtual environment: 

pip uninstall matplotlib -y