Gesture-Controlled Tello Drone- Rapolas Kairys

Gesture Controlled Tello Drone Project

Goal of the Project

The main objective of this project is to control a Tello drone using gesture recognition from a laptop camera. Users can raise their arms in specific poses to make the drone move left, right, up or toggle flight (take off/land) by holding an “UP” pose for four seconds. This project aims to:

• Provide a way to interact with and control a small drone using hand gestures.
• Explore computer vision and machine learning for gesture recognition.
• Demonstrate real-time controls using multithreading to have a smooth video feed.

Description

The system uses:

• MediaPipe Pose Estimation to detect body landmarks (shoulders, elbows).
• OpenCV for video processing.
• DJITelloPy library to send commands to the Tello drone over Wi-Fi, handling takeoff, landing, and movement.
• Multithreading to ensure that drone commands (which can block) do not freeze the camera feed or the user interface.
• Custom gesture logic to determine gestures (LEFT arm up, RIGHT arm up, both arms up, or none).

Controlls

When the user performs a gesture in front of the laptop camera, the system detects it and translates it into a drone command:

• Holding both arms raised for 4 seconds toggles flight (either takeoff or land).
• Once in the air, raising both arms makes the drone go up.
• Raising only the left or right arm makes the drone move left or right.
• Doing neither results in a hover command.
• The drone moves 30cm for all commands, which can be changed in drone_controller.py.
• The command has to be held for 1.5 seconds to take effect. This helps prevent accidental commands and ensure safety.
• While the program is running and a drone is connected pressing "t" makes the drone take off/land. Pressing "q" shuts down the program.

Steps Taken

1. Environment Setup:
   • Installed necessary Python libraries: mediapipe, opencv-python, djitellopy.
   • Created a virtual environment to keep dependencies organized.
2. Implemented Gesture Detection:
   • Used Mediapipe’s Pose Estimation to identify shoulder and elbow landmarks.
   • Determined a gesture by comparing y-coordinates of elbows vs. shoulders (e.g., elbow above the shoulder).
3. Drone Controller:
   • Developed a separate background thread for drone commands.
   • Stores only one command at a time and executes it before accepting the next.
4. Main Application Loop:
   • Captures frames from the laptop camera in a separate thread to avoid UI lag.
   • Performed gesture recognition in the main loop, and if needed, updates the drone command.
   • Displays HUD info: current command, active command, battery status.
5. Testing and fine Tuning:
   • Adjusted arm-raise thresholds for better recognition accuracy.

Algorithm overview

1. Threaded Camera Capture
   • A dedicated camera thread continuously reads frames from the laptop camera (cv2.VideoCapture).
   • The latest frame is stored in a shared variable accessible to the main loop.
2. Pose Detection with Mediapipe
   • Each new frame is passed to the Mediapipe Pose module.
   • Landmark positions for shoulders and elbows are extracted.
3. Gesture Classification
   • Compare elbow y coordinate to shoulder y coordinate:

   • If both elbows are above their shoulders, the gesture is “UP.”
   • If only the left elbow is above, that’s “LEFT.”
   • If only the right elbow is above, that’s “RIGHT.”
   • Otherwise, “HOVER.”

4. Flight Toggle Logic
   • A timer tracks continuous “UP” gesture. If it persists for 4 seconds, we toggle drone flight state (takeoff or land).
5. Command Execution
   • A drone controller in a background thread executes any command (TOGGLE_FLIGHT, LEFT, RIGHT, HOVER) without blocking the main loop.
   • The main loop continues updating the camera feed avoiding freezes.
6. HUD & Feedback
   • The system displays the command currently recognized, the active command (the one being executed by the drone) and battery level.

Links

• Source code
• Video example