Category: Crazyflie

Home / Blog

Alternative Charging Solutions for Crazyflie Swarms

  2025-07-21  |     |    Leave a comment

Today’s blogpost comes from Joseph La Delfa, who is currently doing his Industrial Post-Doc with Bitcraze.

The Qi deck and the Brushless charging dock allow you to start charging a Crazyflie quickly, without having to fiddle with a plug or a battery change. But when you need to charge 10 or more Crazyflies 2.x and don’t want the weight penalty of the Qi deck then some some other solutions are needed.

This blog post is about a couple of chargers I made for the Crazyflie 2.x for my research prototypes. I research interaction design, which often means building something new and then putting in the hands of a user and getting them to try it out. What is important in these scenarios is that when there is unexpected behavior, they don’t think that the prototype is bugging out or broken. One way to prevent this is to make things that have a higher quality to raise the expectations of the user. This can help them stay immersed in the interaction and not look over to me when there is unexpected behavior and say… “is this working properly?”

Wiring Harness for Drone Chi

This charger is essentially a pair of JST 2-pin extensions for a 1S battery charger that I soldered together. Then weaved them through some fake hanging plants. With the drones already looking like flowers for the Drone Chi project, they blended well into the fake plants and all the wires were well hidden. When you wanted to fly, you would disconnect the battery from the wiring harness. Plus it brings the nice experience of picking a flower from a bush before you start flying!

Magnetic Mantle Piece Charger for How To Train Your Drone

This charger allows 10 Crazyflies to charge from their USB ports, but on a bit of a statement piece charger that lived in the lounge room of a group of friends who were participating in a month-long user study during the How to Train Your Drone Project. This charger contained a powered USB hub with cables running through each of the medusa like tubes rising from the base. What made this charger special was the magnetic USB charging adapters (available widely on e-bay, amazon, temu etc) that were plugged into the the USB ports on the drone. These allowed you to securely place the drone on the charger in one action as the magnetic cables integrated into the charger were always close enough to the drone when you set it down, giving you a satisfying * click * every time! They also gave off a eerie blue glow which I think matched the Crazyflie well.

Our new deck control architecture

  2025-07-14  |     |    Leave a comment

At Bitcraze we like making decks! When we released the Crazyflie 2.0 we were really excited about the new deck connector we put on the platform. Using this, it was suddenly possible to expand the platform, adding new, more complex functionalities years after the initial release. It’s something that we really like about the Crazyflie. Over the years we’ve released a bunch of decks and also updated a few of them as new, improved sensors became available.

Deck limitations

As the number of decks has increased, along with their complexity, we’ve started noticing some limitations. We’ve touched on this a while back in this blog post where you can find more details, but here’s a short summary:

  • Resource sharing in the STM32F4: Mainly DMA conflicts between different peripherals, like conflict for DMA using DSHOT on the Crazyflie 2.1 Brushless and the WS2812b driver for the LED-ring.
  • Bus arbitration and performance: Some decks make excessive use of some buses, which can cause issues with certain combinations like the LPS deck and micro-SD card deck.
  • Deck combinations and pins: As more interesting decks are released and we’re able to carry more weight, users want to combine more decks. Although we try to be smart with pin allocation there’s a limit on how you can combine the decks.
  • MCUs on decks: As the complexity increases, separate MCUs are also included on the decks. Although working well for offloading the main MCUs on the Crazyflie, the complexity quickly increases both for usage and for development. This is something we’ve seen with the AI deck for instance, which contains 2 MCUs.

Like suggested in the original blog post, the solution will be to move more intelligence onto the decks by putting MCUs on them. These MCUs can then use the hardware on the decks without sharing resources with the main Crazyflie MCU and can also help process the data to make the communication with the Crazyflie more high level. But doing this will of course then make the issue raised in the last point even worse. To mitigate this we need to have better control over the decks. Our proposed solution for this is adding a new MCU to the decks which acts as a controller. Being able to switch on/off power, bootstrap and control various aspects of the deck. Some of the features include:

  • Uniquely identify the deck and also identify the model of deck – This will replace the current 1-wire memory subsystem we have today
  • Uses minimal amount of pins, basically only using the I2C pins
  • Use the MCU pins as GPIOs or as various peripherals:
    • GPIO expander enables switching on/off onboard power supply, simplifying bootloading and saving power. It also enables bootstrapping of onboard MCUs, which can be used for selecting what output pins to use for various functionality
    • Bridge I2C to SPI/UART for bootloading of onboard MCU. This would of course be much slower than using the SPI/UART but would simplify bootloading and not need pins allocated on the expansion connector
  • Bootstrapping the board makes it possible to to implement support for duplicate decks, for instance selecting what UART (1 or 2) on startup makes it possible for the driver on the Crazyflie to start up each deck and select what UART is used.

Our implementation

For our implementation of this system we have selected the STM32C011 MCU, as it comes in various packages from very small to slightly larger, so it’s possible to solder by hand. It also has the features we needed. To maximize the the flexibility of the system we don’t want to program in the I2C addresses in production. Even if you disregard the fact that the address might conflict with other I2C devices in the future, it will definitely conflict if you add two of the same type of deck.

To fix this we will automatically detect all the deck-ctrl MCUs on the bus and then move them to individual addresses. This will enable us to change the addresses in the future if there are collisions and also allows multiple instances of the same deck attached at the same time. Below is a video demonstrating this in action, implemented on custom development decks we’ve made for simplifying firmware development. Each deck runs the same deck-ctrl firmware and all 3 are auto-detected at startup.

The future

The current solution will be used on our next two upcoming decks: the new LED deck and the new Lighthouse deck. As we get closer to their release we will publish the firmware for the deck-ctrl MCU on GitHub. If the design turns out well we will keep rolling it out to future decks, increasing the flexibility of the deck expansion system even more.

Teaching Robotics with the Crazyflie

  2025-07-07  |     |    Leave a comment

You might already be familiar with the Crazyflie’s presence in numerous publications across various research fields. However, in this blog post, we’ll return to the basics and showcase some robotics concepts that can be taught using our platform.
The Crazyflie has already found its way into several classrooms such as the “Introduction to Robotics” in the Mechanical & Aerospace Engineering Department at Princeton University, the “Introduction to Control of Unmanned Aerial Vehicles” at UC Berkeley and the “Embedded control systems” at Chalmers University of Technology.
Whether you’re designing a robotics course for undergraduates or developing advanced labs for graduate students, here’s some fields where the Crazyflie can help your students grasp the fundamentals of modern robotics.

Basic Drone Principles

How does the quadcopter generate enough thrust? In which direction should the motors spin? How does the shape of a propeller affect performance?
As an introduction to drones and specifically quadcopters, students can explore these basic principles behind how they work. Then, by flying them, they can better understand the three axes of motion, roll, pitch and yaw and even find out their limitations, such as the ground effect.

Control Systems

What is the difference between controllers? How does a different controller tuning affect performance? How does an estimator work? What types of commands can be sent to a drone?
The Crazyflie platform offers a rich “playground” for exploring the stabilization process from sensor acquisition to motor control, that we often call “stabilizer module“. This includes a variety of controllers, estimators and commanders that can be modified to visualize results in the real world. Also, with the firmware being open-source and modular, it is relatively easy to build your own controller or estimator and integrate it to the platform.

Localization

How can a drone know its position and orientation in 3D space? What is the difference between a local and a global positioning system?
With a wide variety of deck sensors and positioning systems, students can find ways to control the Crazyflie through relative or absolute position/attitude commands. The different sensing methods used in these systems are also interesting to explore – for example, IR signals from the Lighthouse Positioning System, UWB radio from the Loco Positioning System, or optical flow data from the Flow deck v2.

Autonomous Navigation

How could the Crazyflie perform a collision-free trajectory? What is the most efficient way of flying from point A to point B?
In the field of autonomous navigation, the Crazyflie can be treated like any other moving robot by applying existing path planning algorithms or testing newly developed ones. Environment-aware problems are always exciting to work on and the Multi-ranger deck makes them feasible.

Swarm Robotics

What happens when you add another Crazyflie to your setup? How could multiple Crazyflies operate in a swarm? How could you make sure that they won’t collide? What is the difference between a centralized and a decentralized swarm?
Scaling a system up is always challenging but also fascinating. The examples provided in our Python library help you get a swarm in the air, but it’s up to you and your students to explore how the Crazyflies should coordinate and cooperate.

Small Drone, Big Educational Impact

The Crazyflie ecosystem is a fully capable robotics lab in the palm of your hand. Its flexibility, safety, and robust API support make it ideal for hands-on learning in a wide variety of robotics fields. Integrating the Crazyflie into a university robotics curriculum, gives students the chance to explore, test, fail, and fly their way to mastery.

Improving our Python project management

  2025-06-23  |     |    Leave a comment

With the Swedish summer upon us, things are more calm at Bitcraze. The summer is usually a time for us to look a bit more at fixing infrastructure and other things that we do not have time to work on the rest of the year. One of the things I have been looking at improving lately is the state of our Python projects.

We currently use Python as the default language for everything we do on PC. This includes the Crazyflie lib, Client and other tools for our ecosystem. Over the years the state of the Python projects have greatly evolved. It started in ~2011 with almost no project management at all; just Python files. Then we switched to setup.py/pip support. Recently the Crazyflie client got the pyproject.toml treatment. Now that most Linux distributions prevent pip install-ing packages we need to juggle with venvs in order to use or develop in Python.

In essence, Python started with an easy to use language but has now become quite complex and hard to handle. Things become even more complicated when we take into account CI in Github actions that have to test that our projects actually work with all supported version of Python on Linux/Mac/Windows.

A bit of Rust (tooling) in our Python

As you might have gathered from our previous blog posts over the years, we like Rust quite a bit at Bitcraze and hope to use it more in our products moving forward. One of the great parts of Rust is the quality of the tooling and of the compiler feedback. Cargo as a project management tool helps a lot working with projects in a comfortable and repeatable way.

This is why we are now quite interested in using uv going forward as an official tool to work with the Bitcraze Python projects. uv can replace both venv and pip and makes working with a Python project as easy as working on a Rust one with cargo. It is also very fast and efficient since it is written in … Rust of course :-).

We are also looking at switching from Flake8 to Ruff and Ty for linting and type checking respectively. These two tools, from the same developer as uv are very fast and give very high quality error messages and warnings – this should make it much easier to maintain good code quality.

These changes would mostly be on our documentation and development side. The resulting projects are still compatible with pip and can still be used as they where used before. However we would make sure the projects can be efficiently used with uv.

Example

The Crazyflie client is currently already fully able to run with uv since it already uses the ‘new’ pyproject.toml project config file. So working with the project, from within the project folder, would look like that:

crazyflie-clients-python $ uv run cfclient    # Run the Crazyflie client GUI
(...)

crazyflie-clients-python $ uv run ruff check  # Check the code, runs in ~100ms!
All checks passed!

crazyflie-clients-python $ uv run pre-commit
      Built cfclient @ file:///(...)/crazyflie-clients-python
Uninstalled 1 package in 0.97ms
░░░░░░░░░░░░░░░░░░░░ [0/1] Installing wheels...
Installed 1 package in 4ms
[WARNING] Unstaged files detected.
[INFO] Stashing unstaged files to /home/arnaud/.cache/pre-commit/patch1750684440-121836.
flake8...............................................(no files to check)Skipped
[INFO] Restored changes from /home/arnaud/.cache/pre-commit/patch1750684440-121836.Code language: Bash (bash)

This last command is a great example of the usefulness of uv: currently one need to install pre-commit on a virtual environment, enter it, and run pre-commit in the project. With uv is just works out of the box. In the back of course, pre-commit is installed in a virtual environment in the project folder. But this is all done automatically.

Finally we will also easily be able to test multiple versions of Python:

crazyflie-clients-python $ uv run --python 3.10 pre-commit
Using CPython 3.10.18 interpreter at: /home/linuxbrew/.linuxbrew/opt/python@3.10/bin/python3.10
Removed virtual environment at: .venv
Creating virtual environment at: .venv
      Built cfclient @ file:///(...)/crazyflie-clients-python
    Updated https://github.com/bitcraze/crazyflie-lib-python.git (3a35d22026c2ed8251b821e4f5b10e67091f811f)
      Built cflib @ git+https://github.com/bitcraze/crazyflie-lib-python.git@3a35d22026c2ed8251b821e4f5b10e67091f811f
░░░░░░░░░░░░░░░░░░░░ [0/32] Installing wheels...                                                                                             warning: Failed to hardlink files; falling back to full copy. This may lead to degraded performance.
Installed 32 packages in 699ms
[WARNING] Unstaged files detected.
[INFO] Stashing unstaged files to /home/arnaud/.cache/pre-commit/patch1750684632-123219.
[INFO] Installing environment for https://github.com/PyCQA/flake8.
[INFO] Once installed this environment will be reused.
[INFO] This may take a few minutes...
flake8...............................................(no files to check)Skipped
[INFO] Restored changes from /home/arnaud/.cache/pre-commit/patch1750684632-123219.Code language: JavaScript (javascript)

And, for the end user, uvx also simplify running the client:

$ uvx cfclient   # Pulls and run cfclient from Pypi
(...)

$ uvx --from cfclient cfloader
      Built cfclient
Installed 22 packages in 164ms

==============================
 CrazyLoader Flash Utility
==============================

 Usage: /(...)/.cache/uv/archive-v0/_OZwn5_zGeTE-qFoK_kEG/bin/cfloader [CRTP options] <action> [parameters]

The CRTP options are described above

Crazyload option:
   info                    : Print the info of the bootloader and quit.
                             Will let the target in bootloader mode
   reset                   : Reset the device in firmware mode
   flash <file> [targets]  : flash the <img> binary file from the first
                             possible  page in flash and reset to firmware
                             mode.Code language: HTML, XML (xml)

This last command would likely be added to all our firmware Makefiles to be used when calling make cload to flash the Crazyflie.

Feedback?

This currently does seem like a good idea to us. If you have any feedback or ideas on how to handle Python projects in a better way we are very interested to hear them. Like I mentioned, the summer is kind of a ‘clean up’ time for us so this is when we have time to look at this kind of things.

Bitcraze at ICRA 2025

  2025-06-09  |     |    Leave a comment

A couple of weeks ago, we were at ICRA 2025 in Atlanta. This year’s ICRA drew over 7,000 attendees, making it the biggest edition yet. We had a booth at the exhibition where we showed our decentralized swarm demo. The setup included a mix of Crazyflie 2.1+ units with Qi charging decks and Crazyflie 2.1 Brushless platforms with our new charging dock. The entire swarm operated onboard, with two Lighthouse base stations for positioning. More details about the setup can be found in the recent swarm demo blog post.

8 Crazyflies flying simultaneously in our decentralized swarm at ICRA 2025

Some of the brushless drones carried our high-powered LED deck prototype to make the swarm more visible and engaging. One of the drones also had a prototype camera streaming deck, which held up well despite the busy wireless environment.

A Different Perspective

This year we were also invited to participate in a workshop: 25 Years of Aerial Robotics: Challenges and Opportunities, where I (Rik) gave a short presentation about the evolution of positioning in the Crazyflie, from webcam-based AruCo marker tracking to the systems we use today.

Usually, we spend most of our time on the exhibition floor, so being part of a workshop like this was a different experience. It was interesting to hear researchers mention the Crazyflie in their work without needing to explain what it is. That kind of familiarity isn’t something we take for granted, and it was nice to see.

The workshop also gave us a chance to talk with both established researchers and newer faces in the field. What stood out most was hearing how people are using the Crazyflie in their work today. It’s very rewarding to see how what we do at the office connects with and supports real research.

Catching Up and Looking Around

One of the most rewarding parts of the conference was the chance to connect directly with people using the platform. We talked to many users, both current and past, and saw new research based on the platform. It was also great to reconnect with Flapper Drones, who build flapping-wing vehicles powered by the Crazyflie Bolt. And it was nice to see HopTo on the exhibition floor for the first time. The company is a spin-off from the Robotics and Intelligent Systems Lab at CityU Hong Kong, which published a Science Robotics paper on the hopcopter concept that used a Crazyflie. We also had the chance to catch up with a maintainer of CrazySim, an open-source simulator in the Crazyflie ecosystem. It’s always valuable to connect with people building on top of the platform, whether through research, hardware, or open-source tools.

Wrapping Up

ICRA 2025 was packed with activity. From demoing the swarm, to the workshop, to hallway conversations, it gave us a lot of valuable feedback and insight. Thanks to everyone who stopped by, joined a talk, or came to say hello.

Empowering Innovation in China: Bitcraze and NOKOV Motion Capture Forge a Strategic Partnership

  2025-06-02  |     |    Leave a comment

As the demand for open, modular, and research-grade robotics continues to grow, Bitcraze is entering a strategic distribution partnership in China, one of the world’s most advanced and fast-evolving markets for robotics and education.

Researchers, educators, and industrial developers in China will benefit from easy access to Bitcraze’s entire product ecosystem. This includes high-performance indoor drones, positioning systems, and modular development tools widely used in academia and R&D across the globe.

Our new exclusive agreement with NOKOV Motion Capture, marks a step forward in expanding access to our autonomous drone systems and robotics development kits across China.

Expanding Access for China’s Robotics Community

Through NOKOV Motion Capture, customers in China gain professional support in Mandarin, short delivery times, and access to official training, demos, and bundled solutions. Together, we’re making it easier than ever for Chinese institutions to explore autonomous flight, precision tracking, and open-source robotics innovation.

A Powerful Integration of Motion Capture and Flight

One of the most exciting aspects of this partnership is the technical synergy between NOKOV Motion Capture’s industry-leading motion capture systems and Bitcraze’s versatile flight platforms. NOKOV Motion Capture’s optical tracking technology is already a staple in academic and industrial research labs throughout China.

By integrating this with Bitcraze’s drones and positioning systems, users can achieve highly accurate, low-latency indoor positioning, conduct repeatable flight experiments with synchronized motion data, and enjoy a seamless workflow from trajectory capture to analysis.

This combination opens up new possibilities for research in fields like robotics control, swarm behavior, artificial intelligence, and simulation.

Supporting Research, Education, and Development

Bitcraze’s systems have earned the trust of top universities and laboratories around the globe. With this partnership, we continue to support Chinese institutions working on:

  • Swarm robotics and AI research
  • STEM and engineering education
  • Indoor navigation and environment interaction
  • Lightweight aerial prototyping and simulation

We believe in giving innovators the tools they need to experiment freely, iterate faster, and go further.

Start Your Journey with Us

Whether you’re designing new robotic systems or preparing your classroom for hands-on drone-based learning, Bitcraze and NOKOV are here to support your ambitions.

If you’d like to learn more or get started with our products in China, please reach out to NOKOV for local support and information.

https://www.nokov.com/products/robotics/crazyflie-crazyswarm-platform.html

https://en.nokov.com/products/robotics-motion-capture/crazyflie-crazyswarm.html

Together, we’re making robotics innovation more accessible, collaborative, and inspiring for everyone.

Fun Friday Project: Crazyflie with a Claw

  2025-05-19  |     |    3 Comments

The ability to attach expansion decks to the Crazyflie platforms without modifying their electronics allows experimenting with different hardware components. Most existing decks contain different types of sensors that are used for positioning and collecting data. On this Fun Friday project that has been running for the past couple of months, I explored adding mechanical principles to the Crazyflie with the long-term goal to create a working claw to grab and transfer objects.

The claw

The claw mechanism is built on a DC motor. The motor shaft is connected to a worm gear, which drives the claw to open or close depending on the direction of rotation. All the parts are 3D printed and designed from scratch.

The deck

Making the DC motor rotate in both directions requires reversing its polarity, which can be done using an H-bridge. So, the deck controlling the claw, is essentially an H-bridge that uses VCC 3V, GND and 4 GPIO pins on the Crazyflie. This way it can be compatible with the Lighthouse positioning deck. The circuit consists of 4 Mosfets (2 P-type and 2 N-type) and 2 pull-down resistors.

How it works

When designing a custom deck for the Crazyflie, you need to initialize it with its own drivers. The drivers for the H-bridge deck contain 2 basic functions; the one that opens the claw and the one that closes it. They are triggered using 2 float parameters (clawOpen and clawClose), and remain active for the number of milliseconds specified by the value of each parameter.

Experiments

Since the entire claw setup weighs 29g, I used 2 Crazyflie 2.1 Brushless drones, to equally share the weight, while one of them controls the claw. Together, they can lift up to 74g. A fishing line is attached underneath each drone and the claw can slide along it, keeping it always centered between them. For the load, I used a Crazyflie 2.1+ with a lighthouse deck attached and its motors removed, to reduce its weight. When the script starts, the initial positions are collected and a flight sequence for the swarm is created based on them. Then, the swarm takes off and approaches, grabs, lifts and transfers the load.

Next steps

The initial goal of grasping and transferring objects with a flying claw has been achieved. However, in the future I plan to make the system more robust and easy to use. Some points that I might focus on:

  • Making the whole setup lighter – replace the current motor with a lighter one, print with lighter materials.
  • Improve the controller tuning to damp the oscillations and make the flight more stable.
  • Implement a control system to keep track of the claw’s state – add limit switches.

Bitcraze’s Infinite Flight: Recent Progress in Persistent Autonomous Drone Operations

  2025-05-12  |     |    Leave a comment

Imagine a drone that can fly indefinitely, autonomously recharging and navigating its environment with minimal human intervention. For corporate innovators designing proof of concept solutions or researchers seeking to push the boundaries of autonomous systems, Bitcraze’s Infinite Flight project represents a novel opportunity.

Since Bitcraze first introduced the “Infinite Flight” concept in 2023, the idea of a Crazyflie drone that can operate for days, autonomously recharging and executing missions, has steadily moved from experiment to practical tool. For those working in robotics, automation, or research, this is a quick update on what’s changed and why it matters.

What’s Changed Since the last Infinite Flight?

Hardware and Firmware Improvements

  • Crazyflie 2.1 Brushless now features improved power efficiency and longer flight times, which is essential for multi-day operation.
  • Charging Dock Upgrades: The move from Qi wireless to contact-based charging has made energy transfer more reliable and reduced cycle downtime.
  • Firmware Stability: The latest firmware (2025.02) brings fixes for brushless ESC flashing, improved default parameters, and more robust long-duration performance.
  • Host Software: The cfclient now uses PyQt6 for better graphical performance, and cflib’s new full-state setpoints offer more precise control.

Navigation and Autonomy

  • Recent work on visual route following enables Crazyflie to retrace long paths using snapshot-based visual homing, reducing drift even on resource-constrained hardware.
  • The autopilot’s app layer now makes it easier to implement custom, persistent behaviors without deep firmware changes.

Real-World Applications of Infinite Flight

Research and Industry Applications

  • Environmental Monitoring: Continuous data collection for air quality or wildlife studies, where drones need to operate for days at a time.
  • Industrial Inspections: Persistent monitoring of infrastructure like wind farms or power grids, reducing the need for human intervention.
  • Swarm and Formation Flight Research: Some labs are using Crazyflie to simulate spacecraft formation flying or to test swarm coordination algorithms over long durations.
  • Route Following: The new visual homing approach allows for reliable, repeatable long-range missions, which is especially valuable for mapping or inspection tasks.

Why Infinite Flight Matters

Long-duration, autonomous operation is a key enabler for real-world robotics. The recent hardware and software updates make Crazyflie a more practical platform for those kinds of experiments-whether you’re working on persistent autonomy, adaptive navigation, or multi-agent systems.

If you’re experimenting with similar ideas or have a use case that could benefit from multi-day drone operation, it might be worth a look at the latest Infinite Flight developments. As always, feedback and collaboration from the community are welcome.

Start your Infinite Flight Now

Ready to experience the power of uninterrupted autonomous flight? The Infinite Flight Bundle equips you with all the essential tools to keep your Crazyflie 2.1 Brushless airborne around the clock.

The package leverages the Lighthouse positioning system, providing precise on-board tracking across a 5x5x2 meter area. With accuracy reaching below 10 cm and minimal jitter, your drone can safely navigate its flight path while autonomously docking on a charging pad. Once recharged, it’s ready to lift off again—enabling continuous flight operations without manual intervention.

State of the Crazyflie mobile apps

  2025-04-21  |     |    Leave a comment

For quite some time now we have had mobile apps that can be used to control the Crazyflie 2.x quadcopter. There is one iOS and one Android app available. There used to be a prototype of a Windows phone app but it has not survived the demise of Windows on phone (fun fact, the windows phone app can be compiled to run on XBox, however there is no USB access in there so it is quite useless). In this blog post I want to talk about the state of the apps and a possible future for them. As usual with me, the future should include a bit ot Rust :-).

Android app

The Android app is the oldest of the mobile apps, it has been created originally to be used with a Crazyradio conncted to an Android phone over USB. Then, when we released Crazyflie 2.0 with Bluetooth Low Energy, BLE was added to the app to be able to Connect to a Crazyflie without radio attached.

Over the years, the Android app has mainly been maintained by FredG, one of the very first Crazyflie contributors. The app supports controlling Crazyflie using touch-control as well as using an Android-supported Gamepad. It also has support for showing the Crazyflie console, controlling some decks and assisted flight using the flow deck.

It also supports updating the Crazyflie firmware using a Crazyradio connected on USB. This functionality is unfortunately broken since we altered the update process when changing the Crazyflie bluetooth stack last year.

The Android app is also working on Chromebook. This means that it can be used to fly the Crazyflie form a chromebook using Crazyradio of BLE. This is one of the only way to control the Crazyflie from Bluetooth on a laptop.

iOS app

The iOS app is newer and much simpler. It has had a couple of really good contribution over the years but overall it has seen much less development than the Android app. I have tried to keep it up and working but nothing more so far.

The iOS app was released when we made the Crazyflie 2.0. Since iOS does not let us communicate with USB devices, it can only work using Bluetooth Low Energy. It can control the Crazyflie using touch control as well as motion control using the IPhone gyroscope.

The iOS app also had support for updating the Crazyflie over Bluetooth, however, like for the Android app this is now broken and it has been removed in a recent release. I hope to be able to add it back soon.

With the advent of the Apple Silicon Mac, the iOS app is now also a Mac app. Like for the Android app on Chromebook, this gives the unique ability to communicate with the Crazyflie over Bluetooth from a computer. However it still has no USB support for Crazyradio and until we implement Gamepad support there is no way to control the Crazyflie from a Mac using the app.

The future

Some of the biggest issues for the development of the mobile app so far has been a lack of specification and the difficulty of re-implementing Crazyflie protocol for each app.

For the former, the apps have been created at a time where flying the Crazyflie manually was one of the major use-case. Nowadays, it is much more common to fly autonomously. This means that the apps should be able to do more to be really useful. Manual flight might still be needed to test the Crazyflie or just to play around. But the app could also have a much greater use for things like assisting in setting up positioning system or swarms. We are still not sure what would be needed or useful yet so if you have any ideas please tell us here as a comment or on Github discussions.

For the later, the difficulty of re-implementing the Crazyflie lib, this is something we have had problem with on multiple front. For example this is also a problem for ROS support and for Crazyswarm. The main problem is that the official Crazyflie lib is implemented in Python, and Python happens to not be a good choice for most cases due to limited portability and performance. One solution we have been imagining and working towards is to implement the Cazyflie lib in Rust and then implement binding for Python, C/C++, Java and Swift. This will cover our current python client, ROS, Crazyswarm as well as all the mobile app. It should allow to get much more done much more easily on mobile, since we will not have to start by re-implementing the wheel each time and will be able to focus on actual functionalities.

One idea, would be to start now with implementing the Crazyflie update algorithm in Rust and to use is from python and the mobile apps. This is a good first target, since this is a non-trivial really annoying piece of code in all languages, and it is also one that must be as bug-free as possible. So having a single implementation that is well tested and can be used everywhere would be very beneficial to the Crazyflie ecosystem.

I hope I managed to convey where we are and where we want to go with the mobile app. If you have any feedback please tell us about it.

A high powered LED-deck prototype

  2025-04-14  |     |    Leave a comment

As some of you may have noticed, the current LED-ring deck doesn’t play nice with the Crazyflie 2.1 Brushless. The culprit? A resource clash between the DSHOT motor signals and the WS2812 LED driver used for the LED-ring.

But good news! We’re prototyping a new LED deck that solves the conflict by switching to I2C communication. Not only does this fix the compatibility issue, it also gives us a chance to improve its features. Here’s what we’ve improved so far:

  • Using a highly efficient high powered LED
  • DC/DC driving circuitry to improve LED driving efficiency
  • 1W on each channel (red, green, blue, white)
  • LEDs on both sides so it can be mounted both on top or on bottom of the Crazyflie
LED-deck mounted underneath a Crazyflie 2.1 brushless
LED-deck with a 3D-printed diffuser mounted underneath the Crazyflie 2.1 brushless

The LED we’re using is very powerful and the light is emitted from a small area, so a light diffuser is needed to get a more pleasant light. Designing something that can be manufactured is the next step of the project. Make sure to follow our blog to get more updates on this project.