Crubyflie - A Ruby client and libraries for Crazyflie

Crubyflie is a Ruby rewrite of the Crazyflie quadcopter Python client libraries, with some customizations.

The Crazyflie is awesome, but I did not know where to start contributing. Therefore I thought that rewriting the code in Ruby would be one way of knowing what is going on and how it works. Along the way I took the time to document all the code so that others can understand it and create tests.

Disclaimer

Crubyflie is in early stage of development, very untested.

Features

Crubyflie can be used to fly a Crazyflie device using a Joystick and the Crazyradio USB dongle
Crubyflie exposes an API that allows to control the copter, read logging, parameters and console easily
Crubyflie runs headless

Not included...

No fancy UI.
No flash utility (yet?).
No idea how this works in other OSs that are not Linux, but in theory it should work in all with some small fixes. I welcome you to take on this task if you are interested.
No support for Ruby <= 1.8.7 (maybe it works who knows... I haven't tested but since Crubyflie relies heavily on threading probably it does not work so good).

Fyling the Crazyflie

The easiest way to do it is to run the crubyflie command. This will connect to the first visible quadcopter using the first available joystick on your computer (you can modify this parameters with the appropiate flags):

> crubyflie2.0 -h
Options:
  --joystick-id, -j <i>:   Joystick ID (default: 0)
       --cf-uri, -f <s>:   Crazyflie URI (defaults to first one found in scan)
       --config, -c <s>:   Joystick configuration, defaults to default cfg in configs/ (default:
                           /usr/lib64/ruby/gems/2.0.0/gems/crubyflie-0.0.1/lib/crubyflie/input/../../../configs/joystick_default.yaml)
             --help, -h:   Show this message

A template/default configuration file (which works for me and my PS3-like controller :)) is provided with the gem (in the configs/ folder). You should modify this file to fit it to your needs (configuration parameters are commented). The most tricky parameter in axis is the :max_change_rate. Depending on your controller, you will find the input is excessively throotled or not. I recommend that you play with this value.

If you are wondering about your Joystick's axis IDs, ranges etc, you will find a sdl-joystick-axis.rb script under tools that lets you open a joystick and check what the SDL library can read from it. It might come handy.

If you need help just open an issue or contact me.

Using the Crazyflie API

While both Python and Ruby APIs expose access to params, logging, console and commander facilities, Crubyflie does it in sligthly different way.

Crubyflie access to facilities is offered fully under the Crazyflie instance object, let's see it as code:

require 'crubyflie'
include Crubyflie

# Connect
@cf = Crazyflie.new()
@cf.open_link(@radio_uri)

# Interface to the logging facility
@cf.log.create_log_block(...)
@cf.log.start_logging(...) do |log_values|
  ...
end
@cf.log.stop_logging(...)
@cf.log.delete_log(...)


# Interface to the param facility
@cf.param.get_value(...) do |value|
  ...
end

@cf.param.get_value(...) do |value|
  ...
end

@cf.param.set_value(...)

# Interface to the commander facility
@cf.commander.send_setpoint(...)

# Interface to the console facility
@cf.console.read do |value|
  ...
end

That's pretty much all. As you see, instead of declaring callbacks, registering them etc. We let the user pass blocks, which are run when the data is available. In Crubyflie, params are read and set synchronously, while the block passed to start_logging() will be called repeteadly and asynchrnously until stop_logging() is invoked. Console offers both synchronous read() and asynchronous start_reading() options.

There are some examples in the examples folder. Read the gem documentation to get full information of the parameters for each function call.

Contributing

Contributions are awesome! :) I'd love some help here, so be invited to open issues, send pull requests or give me your opinion.