Category: Crazyradio

Before we start settling down and preparing for Christmas, it’s time for another release! The last one was before the summer in July, and we’ve had quite a few changes on the development master branch that we’d like to share. You can now download the latest Cfclient through pip and install the newest firmware on the Crazyflie to 2023.11 via the CFclient.

Latest changes in CFclient and Cflib

The most significant change in the CFclient is that we have finally transitioned from QT5 to QT6 for the GUI graphics. Additionally, we have addressed some issues with the toolboxes. Finally, we have added an information box to indicate the state of the supervisor, such as whether the Crazyflie is considered tumbled, flying, or if a restart is required because it is locked.

Cfclient when the crazyflie is tumbled with supervisor info

For the backend, namely the Crazyflie Python library, some important changes have been implemented. Along with fixes to the parameter and logging framework, full-state setpoints have been introduced. This feature has existed in firmware for a while due to the Crazyswarm1 project (now Crazyswarm2), but it wasn’t implemented in the cflib until now. Additionally, it’s now necessary to use `notify_setpoint_stop` in cases of switching between high-level setpoints and regular position setpoints. There is also a generic motion capture example now based on the libmotioncapture library.

Note that even though the CFclient has been converted to QT6, there are several examples in the Cflib folder that have not been updated yet. This will be fixed soon, and a ticket has been created for it. Additionally, in the Bitcraze-VM, there have been some reported issues with QT6 (see this ticket).

Latest changes in the firmware

The firmware has undergone some important changes too. On the STM side of things, the hybrid TDOA mode has been merged (check out this recent blog post). This feature is still considered experimental, so please refer to the documentation for the right settings. Additionally, support for the supervisor information box in the CFclient has been added. To utilize it, both the firmware and CFclient need to be updated. There is also a new example demonstrating communication between gap8 and cpx. Last but not least, it is now possible to create Python bindings for portions of the Kalman filter, mainly for the Loco positioning system. On the other hand, the NRF firmware has no added functionalities except for some build changes and fixes.

Crazyradio2 + LPS tools

We’ve also made some improvements in other firmware or tools. Starting with the Crazyradio2, which includes fixes for broadcasting (important for you Crazyswarm2 folks!). We also aimed to make a new release of LPS tools since we heard that people were experiencing issues with USB devices. Unfortunately, there are some problems with the GitHub release actions, so that will likely be delayed. For anyone facing USB issues, you can install the LPS tools from source with Python following the ReadMe’s instructions.

Release details and Remaining issues

So here are the details of all that is released:

Some things still require attention that are a bit affected by this release, but we haven’t had the time to fix it yet:

  • Fix issues with LPS tools and release (see this ticket)
  • CFclient seems to be broken on the bitcraze-VM (see this ticket)
  • CFlib examples with QT-based GUI are still on QT5 (see this ticket)
  • The newest CFclient seems to need additional packages in some cases ( see this and this ticket)

Please let us know at if you are having more problems.

Developer meeting this Wednesday

As we already announced last week in the Monday blog post, we will be having a developer meeting this Wednesday (6th Dec, 3 pm CET) regarding the Flow deck (refer to this discussion thread for joining information). Since we usually don’t fill up the entire hour, the last part of the developer meeting is available for some generic support questions face-to-face (online), including questions about the release!

As you might have noticed, most of our bundles are currently unavailable because Crazyradio PA is out of stock. We are currently finishing the production for the Crazyradio PA replacement, Crazyradio 2.0 which means that, if everything continues to go well, it should be in stock and ready to ship in a couple of weeks.

One of the first produced Crazyradio 2.0
One of the first produced unit of Crazyradio 2.0, fresh out of a successful run in the test rig

Crazyradio 2.0 is designed to be a drop-in replacement for Crazyradio PA as well as an improvement that will allow new development and improvement for the communication with Crazyflie(s). Among the hardware change we have:

  • Much more powerful microcontroller: the nRF52840, a Cortex-M4 at 64MHz, 1MB of Flash, 256KB of ram with a much more flexible 2.4GHz radio hardware compared to Crazyradio PA.
  • Safe and easy to use Bootloader with button to launch it for easy upgrade
  • RGB LED for richer status indication
  • The same SWD debug port as on the Crazyflie 2.0 for easy development and debugging
  • As on Crazyradio PA, a radio power amplifier with a 20dBm (100mW) output power
  • Only support 1Mbit/s and 2MBit/s bitrate (Crazyradio PA also supported 250Kbit/s)

The improved microcontroller and safe and easy to use bootloader are the most important as they will allow us to experiment and implement new radio protocols over time. Things like peer-to-peer protocols, channel hopping and link cryptographic protection are now possible to work on.

All these new functionalities will come later though. So far we have been really hard at work to get the hardware ready and out as a Crazyradio PA replacement. To achieve that goal we have developed two version of the Crazyradio 2.0 firmware:

  • The Crazyradio2 firmware that implements the same radio protocol as the Crazyflie 2.0 but has a new improved USB protocol that improves performance and allows for the development of new radio protocols. It will also not require any driver on Windows.
  • The Crazyradio2-crpa-emulation firmware that emulates a Crazyradio-PA USB and Radio protocol. This version of the firmware allows to use the Crazyradio 2.0 with any client that supports Crazyradio PA.

Since support for the new USB protocol is not implemented in any clients yet, we are shipping the Crazyradio 2.0 in bootloader mode. When plugged in a computer for the first time, Crazyradio 2.0 will appear as a USB disk drive:

Clicking on README.HTM will open the web-browser to the Bitcraze website page that lists both available firmware with explanations of which one to choose. At first the CRPA-emulation firmware will likely be the most useful but over time the new Crazyradio2 protocols will be the best choice. Once the firmware downloaded it can just be drag-and-dropped in the Crazyradio 2 drive and the radio will restart in firmware mode and be ready to use!

Pressing the button on the Crazyradio when inserting it in the PC will launch the bootloader again and we are planing on making future updates possible via the Crazyflie clients as well. This is an exciting time as we will now be much more free to experiment, iterate and eventually greatly improve the communication capabilities of Crazyradio as well as of the Crazyflie quadcopters!

Now for the more practical information: if everything goes well Crazyradio 2.0 will be available in the bitcraze store the last week of April 2023, we are going to sell it for 40 USD. This means that most bundles should also be back in stock with Crazyradio 2.0 replacing Crazyradio PA in the bundles.

As we have talked about in previous blog post, a big work, and a big change, coming to the Crazyflie is the development of a new communication stack. We are organizing an online dev-meeting about this the Wednesday 22th of February 2023 at 15:00 CEST, if you have any feedback, opinion, ideas or just want to talk to us, you are welcome to join. More information on github discussion.

The current communication protocols used by the Crazyflie are 10 years old by now and starts to be the limiting factor for new experiments and for improving the platform. We are starting to work on it to make the Crazyflie protocol for the next 10+ years. Among the things we have been looking at, and want to work on, are:

  • Making a new USB radio dongle with extended capabilities: Crazyradio 2.0
  • Making new low level radio protocol implementing channel hopping and P2P communication making use of the new Crazyradio 2.0 capabilities.
  • Making a new RPC-Based communication protocol to make it easier to develop new functionality and interfacing with framework like ROS2
  • Defining interface with other part of the system like decks using the same RPC protocol, this would make it easier to develop new deck by limiting the number of project to modify each time a deck is developed.
  • It has also been pitched internally to write the Crazyflie lib in Rust with binding to Python/C++/Javascript/… unifying the host part of the ecosystem and so simplifying the development of application connecting the Crazyflie.

As you can see, this discussion spans to everything that touches communication from the Crazyflie to outside systems as well as with decks. We think there is a way to make things much better and easier to work with. If we have some time left in the hours we can also handle some general support questions.

If you are interested in the topic please join us on Wednesday and let’s talk about it! You can check the joining information on github discussion. These dev-meeting are not recorded, they are intended as a forum where we can talk together about the Crazyflie and its ecosystem. Welcome!

As already announced in a previous blog post, we have been working on a replacement for the Crazyradio PA. Crazyradio is the USB dongle used to communicate with Crazyflie 2.1, Crazyflie Bolt and any other 2.4GHz radio board we are making. We are also visiting FOSDEM in Brussels at the end of the week and will organize a community dev-meeting about Crazyradio and communication end of February: more on that at the end of the post.

Crazyradio 2.0 will have the following characteristics:

  • Based on the nordic-semiconductor nRF52840
    • 64MHz Cortex-M4
    • 1024KB flash, 256KB ram
    • Radio supporting Nordic protocol, Bluetooth low energy as well as IEEE802.15.4
    • 1Mbps and 2Mbsp bitrate to Crazyflie
    • USB full speed (12Mbps) device
  • Radio power amplifier providing up to +20dBm output power
  • ‘Drag and drop’ bootloader with physical button to start in bootloader mode
  • Same debug port as on the Crazyflie for ease of development

One of the main changes versus the Crazyradio PA will be the available CPU power and ease of development: this will allow to experiment with and implement much more advanced communication protocol like channel hopping and peer-to-peer communication.

On the software side, there will be two modes available for Crazyradio 2.0: a compatibility mode that emulate a Crazyradio PA and should work with all our existing software as well as a new Crazyradio mode that will have a much improved USB protocol allowing for more efficient communication when controlling multiple Crazyflie as well as making it easy to support more protocols in the future.

These two modes will be available as two different firmware and the user can ‘drag and drop’ the firmware with the wanted mode.

As for the Crazyradio PA (version 1), sourcing the components for it has been a bit challenging lately. We will sell Crazyradio PA as long as we have stock for it and the software will continue to support it for the foreseeable future.


Kimberly and I, Arnaud, will be visiting the FOSDEM conference at the end of the week in Brussels. If you are there too and want to meet us do not hesitate to drop a message in the comment there, in Github discussions or by mail. It would be great to meet fellow Crazyflie users!

We are also planning an online dev-meeting about Crazyradio 2.0 and communication the 22nd of February 2023. The information about joining will be on Github Discussions. We are interested in talking, and bouncing ideas about radio and communication protocol: with the new Crazyradio we have an opportunity to work on communication protocols to improve them and makes them more useful to modern use of the Crazyflie.