Category: Electronic

In this beginning of 2017 we are proud to announce that there are two new decks for the Crazyflie 2.0.

The first one has been in the works for quite some time, it is the Micro SD card deck. It enables read and write access to a SD-Card from the Crazyflie firmware (where we have also implemented FAT filesystem support). Our first use case for this deck has been to implement high speed logging of the IMU sensors: the SD-Card has much higher bandwidth than the radio so it allowed us to log all the sensor values for later analysis. Another use-case could be to read an autonomous sequence from a file on the SD-Card and implement fully autonomous sequencing in the Crazyflie when used in the Loco Positioning System for example. The SD-Card deck is already available on Bitcraze web-shop.

The Second deck is the Z-Ranger deck, it is a laser time-of-flight ranging deck that measures the distance to the ground. We talked about this deck in a previous post. The manufacturing of the deck should be finished soon and so it will be available in our shop shortly. When using this new deck, the altitude hold stability between 0 and 1.5 to 2m height is greatly improved.

On a final note, FOSDEM 2017 is this coming up this weekend and we are looking forward to meet you there. There will be two presentations related to the Crazyflie, if you want to meet us come at these presentations or get in touch in the comment or by mail. The two presentations are:

We hope to see you there!

At FOSDEM 2016 we met someone from Bosch Sensortec, he was very interested by the Crazyflie and got one. Apparently his college liked the Crazyflie too because soon later we where contacted by Bosch that wanted to make a deck for the Crazyflie containing a brunch of there sensor. We have been tweeting about this board before and now we just pushed the drivers for some of the sensors into the Crazyflie main branch.

The deck has an impressive list of sensor onboard:

  • BMI055: 6 Axis gyro and accelerometer, with closed loop technology gyroscope
  • BMI160: 6 Axis gyro and accelerometer
  • BMM150: 3 Axis magnetometer
  • BMP285: Pressure sensor
  • BME680: Environmental sensor (air, pressure, humidity, temperature).

Thats a lot of data, and there is also an non-populated footprint for a BMF055 which is a BMI055 and an Atmel ARM Cortex-M0 in the same package, this is something that could be very interesting to play with in the future. The drivers and the integration are still in early stage but what has been pushed so far is support for the BMI055 and BMI160. We look forward to tuning those sensors and testing the others as well!

Bosch has made most of the work with this deck them selves and we have provided mainly guidance and support, a big benefit of open source! That has been working great and it has been very fun working with them. We are not sure if this is going to be part of a product yet, as in releasing a deck full of sensors. Please tell us what you think and if anyone would have use for such deck.

Most of the time we have a few prototypes lying around that we’re working more or less on. Sometimes some of these make it into a product if we feel that they might be useful or fun for the community, like for instance the SD-card. Now it’s time for another prototype to be moved to manufacturing, a deck with VL53L0x laser ToF distance sensor.

On the Crazyflie 2.0 (and Crazyflie 1.0 10-DOF) we have a pressure sensor mounted to help control the altitude of the platform. Since air pressure is moving around a lot and the measurement is noisy it’s been very hard to get a rock-solid altitude hold working (although it’s getting closer). Already back when ST released the VL6180X we were looking at it, but the range was too short (10cm max). So when ST released the VL53L0x which has longer range (200cm max) we though this might be a good deck for the Crazyflie 2.0.

So we have a working prototype and thanks to stephanbro and Marcus Grieff we also have the firmware to use it with the Kalman filter. We are currently working at making it work together with the pressure sensor with the current altitude-hold mode.

Currently we’re working on verifying the hardware to make sure the power supply is good enough for it, but then the next step is production. Hopefully it will be available in a couple of months 🙂 Below is a picture of the current prototype.


The logging subsystem of the Crazyflie 2.0 is fairly flexible and easy to use, but despite its nice properties it may still be limiting in some scenarios. Two areas where it is lacking are offline- and high-speed logging. As a step towards solving these problems we are happy to announce support for micro SD-cards in the Crazyflie 2.0 firmware.


We have had a prototype for a micro SD-card expansion deck lying around in the office for a long time but have not had time to write any code for it. Finally we decided to go ahead an fix it and now there is a first basic version in the master branch of the firmware. What we have added so far is a driver for communicating with the deck and support for the FAT file system and that means that it is possible to read or write files to/from a SD-card. We have not yet implemented any means for configuring parameter logging to file but that is something we would like to do in the near future.


The hardware design for the expansion deck is very simple.


If you are eagerly waiting for this functionality it should not be too hard to create your own deck, otherwise we plan to release one sometime in the near future. We can not promise when, but if you need it please let us know as it might change our priorities when deciding what to do.

When the deck is installed all you have to do is build the firmware with 


in the tools/make/ file to enable the SD-card functionality and add your own code in src/deck/drivers/src/usddeck.c to read or write to your SD-card.

We are excited to announce that we have just started the production of the first boards for the Loco Positioning system!
Since this is the first batch of a complex new product, we thought we should be there in person. This time, Tobias and Kristoffer went to visit Seeedstudio, our product manufacturer. It is always very nice to meet them in person and to visit the factory.
Also visiting the factory is always an opportunity to discover a new fashion style!


The first boards to be produced are the Loco Nodes:


After a minor problem: we specified the LEDs to be mounted reversed, quickly found and fixed for this first batch by the Seeedstudios engineers, the production of the nodes is looking good and the first 8 pieces are flawless!


To go with the nodes, we need to have the Loco decks. Like for the other decks we have implemented the test rig based on a Crazyflie 2.0 programmed with special flags for the test. We found some issues with the rig software but it has been quickly sorted out. So the launch of the deck production, tomorrow Tuesday, should be without any hick-ups. This is what a deck test rig looks like (note the Crazyflie 2.0 being attached on the bottom):

In other news we’re welcoming Aman in the Bitcraze team for the summer. Aman is flying straight from Kiruna at the very north of Sweden (before that from Germany and even before from his university in the US). He will be looking at improving control and stability of the Crazyflie. The fist step today was to learn how to fly it manually :-).

As we already talked before in a couple of post, we are currently developping a local positioning system for the Crazyflie based on ultra-wide-band radio DWM1000. This is one of our main focus currently so we wanted to post a short update on our progress.

We have assembled and shipped a couple of LPS system already and so far the performance and progress are great. We now think that we have the copter flying as good as we can have it without running sensor fusion and the control loop in the Crazyflie microcontroller. Next step is to integrate algorithms in the Crazyflie.

We are currently working hard at finishing the design to make it ready for production. We will write more updates about that so stay tuned :).

We have shot a short video demonstrating the current state, see after the video for more information about the setup:

To make this video we have installed 6 anchors. 3 are above the room and 3 at about 50cm from the ground. The Crazyflie has a LPS deck and ranges in a round-robing fashion with all 6 anchors. The ROS driver pulls the ranging, estimate the Crazyflie position, and calculate a corrected roll/pitch/thrust in order to keep it at the pre-defined setpoint. The Yaw is not controlled externally, it is kept by the Crazyflie internal gyroscope only.

The ROS computer was setup according to the instruction on our wiki, and by launching the pf_hover launch file:

roslaunch bitcraze_lps_estimator dwm_loc_pf_hover.launch uri:=radio://0/110/2M x:=1.5 y:=5 z:=1.2

Early Access

For a long time now we have discussed the BigQuad deck which basically can transform your Crazyflie 2.0 into a bigger quad by attaching it to a bigger frame. The first simple prototype we did using the prototype deck was made already in the fall of 2015. As it turns out the BigQuad deck requires plenty of software and ads a whole new level of caution. That along with limited time and resources has slowed down the development progress. To overcome parts of this hurdle we came up with the early access program. It is basically hardware which is ready, but the software is in a early and rudimentary state. This way eager development users can get hold of the prototypes we are working on and to try out the latest and greatest designs. The benefits are mutual, we make it possible for our users to get started with new hardware and development at an earlier stage in the development cycle, in return we hope the community will help out with important feedback and contributions towards finalizing the product. First out in this program is the BigQuad deck.

BiqQuad deck

We run each “early access” project as an open project on github, in this case the repository is named early-access-big-quad-deck and is the focal point. Since many changes in the Bitcraze software stack spans over multiple repositories (firmware, clients, radio and so on), this “early-access” repo is where to post issues or feature requests, discuss solutions and what to implement. We love to collaborate with the community, join the fun!

The current sparse user documentation of the BigQuad deck is put on the corresponding wiki page. Let’s add more!

Crazyflie family

Crazyflie family

Crazyflie 2.0 used in Ericsson Mobile World demo

Erricsson have presented a demo for Mobile World congress using the Crazyflie 2.0 and the wireless charging deck.

The crazyflie was also present for the keynote in the hand of the Ericsson CEO. I is always nice for us to see Crazyflie being used for cool demo and events :-).

Last week and today we have been busy at making the first DWM1000-based LPS system we are currently developing.

As usual with hardware and production nothing goes according to plan. We sometime envy people working only with software, but then we think about how awesome it is do make physical things. Anyway the plan was to start producing the boards middle of last week but some components where missing. Then we discovered that the regulator we chose did not have the right pin-out (we are quite ashamed about this one, we assumed all regulator had the same pin-out ….). Finally we discovered that the reflow oven was melting the plastic component (connector and buttons), adding small pieces of tin-foil over the plastic parts fixed the problem.

At the end, we managed to start production with a good rhythm this afternoon. We have assembled half of what we where aiming for and the last half will be done tomorrow. As announced before we intend to sell this first pre-pre-production to anyone interested in having early access to the local positioning system (we think university, but getting it to the hands of research lab or hackerspace would be awesome too). If you are interested please drop us a mail.

We have also started to document the LPS system, and we have pushed the DWM1000 open-source C driver, nodes and deck driver to our github.

As we have written before we are working on a DWM100-based ultra-wide-band local positioning system, we are making good progress and are getting ready to ship alpha systems. We hope to be able to ship in the following weeks. We aim at shipping these alpha system to anyone interested to test it early.

The alpha anchors and DWM deck will be very close to our expected final system. We are in the process of pushing the source code for it on GitHub, it will have open-source public code before we ship the first system.

We have now stocked enough DWM1000 modules and we are ordering the final PCB design for the anchor. This would allow early access to the technology and for us we would be able to get feedback. We are planning on selling the anchors around 100USD each and the DWM decks 70USD. The price is taking into account that we are manually soldering, testing and shipping ourselves. If you are interested to get access early please contact us (you can find the contact email on the contact page).

We have just made a quick and dirty video tour of our basement/autonomour flight lab. This was shot in one take so it is a bit messy, but our goal was to show our current state. We are using the Crazyflie python client training mode with the automatic controller as a student. This is why I keep the gamepad in my hand most of the time: the first flight is done with me controlling thrust and yaw, the controller controls roll and pitch. The second flight is fully autonomous but I still could take-over control by pressing a button. On a side note these tests are showing how good it is to have a lightweight and robust quadcopter like the crazyflie: the Crazyflie you see in the video has crashed countless time this last mount in the basement, I have not yet changed the motor mounts nor any other part on it.



We are currently working on a local positioning system based on ultra wide band decawave DWM1000 modules for the Crazyflie. We have already written a couple of times about it earlier, and in this post I will describe where we are now. We will also start making a wiki page and add more about the experimentation in the future.

During the end of year 2015, we have made some progress! We just moved to a new office and we now have a local positioning lab in the basement, where we are able to fly a Crazyflie 2.0 autonomously using the local positioning and keeping clear from the walls (I would like to say to keep a stable position, but we are not there yet :-).

As we have shown in previous posts we have electronic boards for the anchors, and the Crazyflie deck:
DWM1000 nodes and deck

We have setup 6 anchors at our office. The configuration is designed to maximize the trilateration precision in the middle of the room. The ranging is done by the crazyflie and then communicated to the ground using the log subsytem. The ROS crazyflie driver receives the ranging and send it to the trilateration algorithm, a particle filter. We can then display the estimated position and use the position to control the Crazyflie position:
graph_dwm rviz_dwm

In order to try to fly autonomously, we have been trying the controller included with the Crazyflie ros driver. We also connected ROS via ZMQ to our python client and the controller we made to fly autonomously with the Kinect. Both work but are far from perfect: they have been tuned for a pretty stable measurement (from a Vicon system or a Kinect) and the output of the particle filter is a bit noisy, mostly for the altitude. We are looking at improving the position control loop and adding sensor fusion for positioning in the Crazyflie 2.0.

Early 2016 will be time to finalize the DWM1000-based local positioning system to be able to distribute it. We are currently writing an open-source C driver for the DW1000 chip and we are finalizing the anchors electronic design. If you are interested in getting such system do not hesitate to contact us, as we are finalizing the design, any input is interesting so that we end up with a system that is easy to use and to setup.