#telloc 📸🎮

Cross-platform C library for connecting to the DJI Tello with video support

This was created for the Roadrunner Dynamics Club.

#What? 🕹️ 🪟 🍏 🐧

This library supports Windows, MacOS and Linux developers who might want to make cool apps to control their fancy flying robot.

#Why? ⁉️

Mostly because existing tello libraries are overly complicated, abandoned, and/or do not work.

This library implements a clean, cross-platform interface for:

• Sending commands and receiving responses
• Receiving video data as RBG images
• Receiving state data as a string

#How? 📖

#Building the library 🚧👷

To build this library, you simply need to install ffmpeg libraries (avformat, avcodec, avutil, swscale).

Windows:

choco install ffmpeg-shared

MacOS:

brew install ffmpeg

Debian/Ubuntu:

sudo apt install libavformat-dev libavcodec-dev libavutil-dev libswscale-dev

Then you should be able to build telloc with CMake.

mkdir build
cd build
cmake ..
make

telloc also comes with a testing program for Windows / Unix-based systems that will attempt to connect to the drone and display information if successful. And Python3 bindings.

mkdir build
cd build
cmake .. -DBUILD_TESTING=True -DBUILD_PYTHON=True
make

#Using the python library 🐍

1. Build The library with python bindings

mkdir build
cd build
cmake .. -DBUILD_PYTHON=True
make

1. Copy libtellopy.so into the tellopy folder

cd ..
cp build/libtellopy.so tellopy

1. Install the python library

cd ..
pip install -e tellopy

#Using the library 🪨

telloc has a simple interface defined in telloc.h. You can read main.c for example usage.

telloc spawns three threads when you call telloc_connect(...):

• the state thread - reads state strings and saves them into a buffer.
• the video thread - reads and decodes video data into an RGB image buffer.
• the keepalive thread - sends a keepalive query to the drone once per second.

To attempt a connection and spawn threads, you can run

tello_connection *connection = telloc_connect();

When you want to send data to a successful connection, you do:

char *command="streamon";
char *response=malloc(TELLOC_STATE_SIZE);
int ret_command = telloc_send_command(connection, command, strlen(command), response, TELLOC_STATE_SIZE)
printf("Response was %s\n", response);

To read the most recent video frame, you can do the following:

unsigned char *image = malloc(TELLOC_VIDEO_SIZE);
unsigned int image_bytes;
unsigned int image_width;
unsigned int image_height;
int ret_video = telloc_read_image(connection, image, TELLOC_VIDEO_SIZE, &image_bytes, &image_width, &image_height);
if (ret_video==0)
    printf("Image: %d bytes; %d x %d\n", image_bytes, image_width, image_height);

To read the most recent state string, you can do the following:

char *state = malloc(TELLOC_STATE_SIZE);
int ret_state = telloc_read_state(connection, state, TELLOC_STATE_SIZE);
if (ret_state==0)
    printf("State: %s\n", state);

#TODO ✔️

• [ ] Use static libraries for ffmepg, build static telloc
• [ ] Save binaries somewhere accessible

#Release Notes 📝

• 2023-02-18: Improved interface by using opaque struct pointer instead of void*
• 2023-03-04: Added python bindings

#License ©️ ❎

This is licenced under the 💥 ⚖️⚖️ Unlicence ⚖️ 🚀, so basically, do whatever you want but please don't sue me.

see LICENSE.