Crazyflie Nano C++ Client Library

First of all, the Crazyflie Nano is an awesome Quadcopter by the guys at Bitcraze. I just love it - and since I'm a C/C++ programmer deep in my heart, I really, really wanted to have a client library in that language (there was none at that time).

That's why I wrote one.

My work is based on Bitcraze's Python Library (see their repos) which (alongside their wiki) greatly helped me understand the communication protocol. Feel free to use the library as you like, as long as you obey the rules of the BSD license.

You can check out the current Doxygen source code documentation here.

What this library is

• A USB connection point to the Crazyflie Nano quadcopter by Bitcraze
• An abstraction layer for the different messages you can send your copter
• A controller framework for controlling the Crazyflie using cartesian coordinates
• A C++ entrypoint for programmers that write programs in C++ (rather than Python)
• The first version was developed, written and maintained completely by me (Jan Winkler)
• Development and maintenance is distributed over the many contributors by now. This is a good time to say: Thank you!

What this library is not

• A bootloader
• Complete
• Bug-free

Where it has been tested

As system architectures tend to differ in what they include and how they are organized, the library doesn't necessarily run out of the box in your system. The library is constantly being tested and built on a couple of Ubuntu versions (see here). Right now, these are:

Distribution	Version	Name	Architecture
Ubuntu Linux	12.04	Precise Pangolin	i386
Ubuntu Linux	14.04	Trusty Tahr	i386
Ubuntu Linux	14.10	Utopic Unicorn	i386
Ubuntu Linux	15.04	Vivid Veret	amd64
Ubuntu Linux	15.10	Wily Werewolf	amd64

So, the current state of the library might or might not run on your system if you differ from those. I'll be more than happy to incorporate pull requests that support more architectures. If you have it running on some architecture not listed here, let me know!

Dependencies

One of the examples included with the library depends on GLFW, which you can install under Ubuntu by apt-get install'ing this:

$ sudo apt-get install libglfw-dev libglfw2 cmake

If you do not wish to depend on GLFW, use the file CMakeLists_noGUI.txt instead of CMakeLists.txt. The example ex-gui will not be built, then.

How to install from binaries

Add the PPA to your debian sources:

$ sudo add-apt-repository ppa:jan-winkler-84 && sudo apt-get update

Install the binary package:

$ sudo apt-get install libcflie

This will of course install the necessary dependencies automatically.

How to build the library from source

First, clone the repository:

$ git clone https://github.com/fairlight1337/libcflie.git

In the cloned folder, do:

$ mkdir build
$ cd build
$ cmake ..
$ make

After that, you will find two directories in the base directory: lib and bin.

• lib includes the built libcflie library (with fitting extension, depending on where you build it). You can link against this library, using the header files contained in include/cflie/ to actually use it.

• bin includes example programs. Currently, there are three:

  • ex-simple shows the most simple usage example of the library
  • ex-replugging shows how to use the lib for allowing re-plugging the USB dongle and letting the copter go out of range and return. Also, event hooks are marked for all these events to execute custom code for all situations.
  • ex-gui displays an OpenGL window that shows a plane based on the current copter orientation. Using the arrow keys, you can control the copter, and when pressing the space bar, you can increase the thrust to the copter. CAREFUL: When starting the program, the copter will start with a thrust greater than 10000, which will start the engines! So be sure to place it far away from objects (or your hands).

How to run the examples (or you own programs)

When running programs linked against and using libcflie, you have to have access permissions for your USB devices set up correctly, as USB devices are not per se accessible by all users on a system.

You basically have two options:

Recommended way: Set up your USB permissions for the CrazyRadio dongle. For this to work, create a new file at /etc/udev/rules.d/99-crazyradio.rules and put this line into it:

SUBSYSTEM=="usb", ATTRS{idVendor}=="1915", ATTRS{idProduct}=="7777", MODE=="0664", GROUP=="plugdev"

For this to work, your user has to be in the group plugdev. To check in which groups you are, type

$ groups

If plugdev is in the list, you're good. If not, let Google explain how you can add a user to a group on your specific system. You will probably have to log out and back in again for the changes to take effect.

Now replug your dongle and you're set. Start the example ex-gui application from the libcflie/build (after typing make) with:

$ ./../bin/ex-gui

Exit the example by pressing ESC.

For testing purposes: Run your programs as root:

$ sudo ./../bin/ex-gui

Again, exit the example by pressing ESC.

Important Notice (concerning development and support)

After developing the core parts of the library and maintaining it for a while, supporting users and co-developers in several projects, I decided to stop actively developing the library further. This is solely due to other time-consuming things in my life, so I won't be able to help you getting your project to run. By now there are lots of forks of the library and example programs using it (try Google'ing it or look at the GitHub forks). I still incorporate pull requests and bug fixes and look after keeping the build farms happy with the source (Travis CI, Launchpad), but can't help your individual projects.