Progress on Local positioning

2015-11-16 | Arnaud | Leave a comment

A we wrote before, we are working on a Ultra-Wide-Band-based local positioning system for the Crazyflie. We are doing slow progress but progress anyway and we wanted to do a small update on it.

We are at our second revision on the anchors, they are now based on an STM32F072 CPU which has the advantage to have an USB bootloader which will useful to update them on the field. We are trying to think about either or not we should implement more communication like Ethernet to the anchor. Our main use-case is to get the localisation in the Crazyflie but we are aware of use-case where the localisation is required on the ground instead. If you have any input on the design of Ultra-Wide-Band anchors please let us know.

We have also made a 3D printed support for attaching the anchors to the ceiling or ground:

As for the localisation, we are able to range from the copter to the anchors and we are logging the range using the Crazyflie 2.0 log subsystem. We have tested logging data in a csv file and running a Particle filter to find the copter position, more about the filter in a future post. So far it looks good but we need a nicer way to visualize the data. The way we are taking is to learn and use ROS.

ROS is a system used by researcher in robotics and it implements a lot of things like visualization and state of the art algorithm. Wolfgang from USC has written a ROS driver for Crazyflie and it is about time we are getting into ROS. It is a learning process for us but the plan is to implement and test the UWB local positioning system on top of ROS, which will allow us to use its components and reduce development time.

New Decks comming soon

2015-11-09 | Arnaud | 3 Comments

Lately we have been busy finalizing new Decks. We have a pretty long list of what we want to release and the first four to come are the bigquad deck, the Buzzer deck, Wifi (ESP8266) deck and a GPS (GlobalTop) deck. Before going further a disclaimer: we have ordered final prototype of these decks so the probability we release them is pretty high, though it is still possible we end up hitting a big bug and then some might be delayed.

The bigquad was covered in previous post. It is a very simple deck: only connectors. It can be used to connect brushless motors ESCs to the Crazyflie in order to control a bigger quad. We have also added connectors to control the Crazyflie from a standard receiver (SPPM input), for GPS, active buzzer, battery telemetry and I2C sensors. The main use case we see for this deck is to be able to develop with the Crazyflie and then go outside and fly with bigger sensors without having to port the code to another platform.

Firmware-wise we are developing support for ESCs and SPPM input.

The Buzzer deck is the second simplest: we have ‘just’ mounted a buzzer on a deck and made the driver for it. As usual with production nothing is easy and selecting the buzzer was surprisingly hard. We wanted a low profile buzzer to be able to put other decks on top of it. We have ordered 20-ish different buzzer from DigiKey and tested all of them to select the best:

The Buzzer driver will be able to play some music as well other sounds. One use case we envision for the buzzer deck is to be able to find the Crazyflie if it has crashed out of sight.

The GPS deck is an old story: we started working on a GPS deck on the Summer 2014 and we even planed to release it at the same time as the Crazyflie 2.0. Unfortunately we had lots of problems with the antenna not working properly when attached to the Crazyflie. After a lot of experimentation, spread over 1 year, we finally endeded up with a design that works: an integrated GPS receiver and patch antenna:

We found the patch antenna to be much less sensitive to the Crazyflie 2.0 ground plane than the previously tested chip-antenna. As for the software part we will implement enough code to decode the NMEA strings from the GPS and makes them available via the log subsystem. We have a prototype of a new GPS tab in the client using a webview and openstreetmap, more on that on a later post.

Finally we have mounted an ESP8266 wifi module on a deck and Crazyflie 2.0 becomes Wifi enabled :-):

So far we are planning on loading the NodeMCU Lua firmware in the ESP8266 which will allow to easily develop wifi connectivity to the Crazyflie. Note that the final board will be based on a different ESP8266 module with chip-antenna.

We will post more in-depth information about those new decks in the following weeks. We will also communicate the release date as soon as we know it.

Moved to The Ground

2015-11-03 | Arnaud | Leave a comment

The last week has been really busy here at Bitcraze. We are working on regular bugfixes, support and new Decks to be release as soon as possible. But at the same time, we have moved our office in a new building (still in Malmö, Sweden) which is a lot of work, even more for us who have a lot of random hardware lying around. We left Minc, the incubator that hosted us since our beginning as full-time company. We where really happy at Minc, it has been a great place to work and evolve. We thought it was time to move to get closer to other hardware companies and to have a bit more space.

We are now at The Ground. It is a co-working space for startups that hosts some very cool companies. We are really happy to have moved there and are just started to settle-in. We now have a lab separated from the office (which is a first for Bitcraze, we are a bit anxious to be so far from the soldering iron but lets see how it works :-). The great news is that we are going to use the basement as an autonomous-flight-lab to develop the DWM-1000-based local positioning system. I am sure we will have more news on that in later posts.

[Show as slideshow]

Another important change: we now have a new member in our team! Björn, who arrived last week, will look, among other things, on refreshing the website and all our communication. The current website state is fully made by hardware engineer and we thought it should be shaped-up a bit.

Björn

SeeedStudio visit at Bitcraze

2015-10-26 | Arnaud | Leave a comment

Seeedstudio is our manufacturer and our main distributor. Last week Mandy from Seeedstudio came and visited us after being at Maker faire Rome. She did a very interesting talk at Minc, our incubator, about manufacturing in China and how Seeedstudio helps with agile manufacturing. The interest was high here in Malmo, it is not often someone from China comes to Sweden and talks about manufacturing. Usually you would have to travel to China to find out more about that.

If you would like to know more about what she talked about the slides are available on Slideshare:

Seeed Manufacturing Service Introduction from Mengmeng Chen

Mandy from @seeedstudio at @mincmalmo. About agile hardware production pic.twitter.com/8dY5SwxE3K

— Bitcraze (@Bitcraze_se) October 22, 2015

Crazyflie and Lua

2015-10-19 | Arnaud | Leave a comment

Last week I was at Lua Workshop 2015 in Stockholm, it was a very interesting conference with lots of interesting people. I also had the opportunity to see the office of King, the host for the workshop, and it gives a lot of idea for fun stuff and toys we could have in our office :-)

On a side note we are organizing a presentation in our office in Malmö the 22nd of October: Mandy from Seeedstudio is visiting us and will talk about manufacturing in China. If you want to come you can register.

Now, back to Lua. Lua is a dynamic programming language that is small, fast and meant to be embedded within other programs. Currently is is used a lot in video games and a bit on servers. It has also be used in deeply embedded system with the eLua project, for example Seeeds sells a Lua-preloaded ESP8266 wifi module. One of our plan for Crazyflie 2.0 is to be able to write deck drivers in Lua.

With Crazyflie 2.0 we are aiming to make a research-grade flying platform more accessible and versatile, hence the expansion capabilities (with decks) and the new API we are writing for it. Lua would fit well in this goal. It would allow to very quicky script and test a device driver. As a bonus Lua being safe (ie. the virtual machine cannot crash the system), there would be no risk of crashing the copter with those kind of driver. The architecture would look something like that:

Though Crazyflie Lua integration has not been prioritized so far, we think it is something that would be interesting to play with it in the future. If anyone is interested into testing and helping out please reach us on Github or on the forum.

Local positioning system measurements

2015-10-12 | Kristoffer Richardsson | Leave a comment

Last Thursday we went to LTH (University of Lund), to the Robotics department, to make some measurements on the ultra wide band (UWB) positioning system we are working on. The idea was to use one of their robots to move a Crazyflie around along well known path, and at the same time record as much sensor data as possible. This would give us data that we can crunch offline.

We placed four anchors around the robot and our positioning expansion deck on the Crazyflie. The Crazyflie collected the data from the positioning deck as well as its internal sensors and streamed the data it over USB to an external computer for storage. We collected the following data:

Distance to the anchors (raw measurements)
Air pressure at the anchors
Air pressure at the Crazyflie
Accelerometers
Gyros

The logs from the robot will give us the real position of the Crazyflie as well as the anchors, and from that we will be able to evaluate the performance of algorithms that use the sensors to figure out the position.

The dataset will be shared with the researchers at Lunds university, they have some interesting ideas they want to try out.

Next step is to crunch the data…

For more information on our UWB positioning project, see Firmware and dwm 1000 nodes

Two Maker Faires

2015-10-06 | Kristoffer Richardsson | 1 Comment

Marcus and Arnaud have packed up and left the Berlin Maker Faire after two hectic days. and last weekend Tobias and I were at Maker Fair New York. It’s a lot of fun showing the Crazyflie, meeting people and getting feedback from the community!

This time we had created a demo where we used a webcam to track the position of the Crazyflie (see older blog post). I really like the demo, it’s pretty minimalistic and shows the awesome capabilities of the Crazyflie as a platform that enables the user to explore and develop on top of it. Just add a webcam, AR-tag some control algorithms, imagination and engineering and you have an autonomously flying Crazyflie!

When Tobias and I arrived at the New York Maker Faire on Friday afternoon to set up the demo, we discovered that our booth was not indoors, but under a roof without walls. And it was windy!

There was no way the control algorithms could manage to keep the Crazyflie at its taget position, so what to do? We tried various ways of tethering it with a string while still flying, but without any success. We had to resort to hanging the copter in a string, but not really flying it. To at least get some use of the positioning system, we used the position of the hanging copter to change the color and intensity of LED-rings on four other copters that we put in the corners of the test rig. Not what we hoped for but what do you do?

My favourite gadget at the New York fare was the Pancake Bot – a must in every home!

The Berlin Maker Faire was organized for the first time last weekend. The venue was a bit smaller than other Maker Faires we’ve been to, but there was lots of interesting visitors and it was held in a very nice old railway-postal building. Fred from our community joined us during the fair and gave us some much needed support in the booth. As for the demo it was working better, but we still had some issues with lighting and the detection of the AR-tag. Room for improvement.

The fair had a drone area, but unfortunately not a lot of drones. We were flying the Crazyflie 2.0 as well as a bigger quad using the Big Quad deck. Aside from that Fred brought a long his even bigger quad that uses the Open Pilot CC 3D.

Big thanks to Fred for showing us Berlin and helping us out!

Maker faires, conference and first Bitcraze meetup in Berlin

2015-09-28 | Arnaud | Leave a comment

This year we decided to save some time and split up for the last two Maker Faires. So last weekend Tobias and Christopher went to the Maker Faire in New York. They had a great but hectic time. More about it in a next post.

Meanwhile me and Marcus are going to Maker Faire Berlin next week end, from 2015-10-03 to 04. We will be standing in the Seeedstudio booth showing the Crazyflie. We’re also planning on having our first ‘meetup’ since we are sure to have at least Fred, the main Crazyflie Android client maintainer :-). We have created a forum thread to discuss it. If you are in Berlin next weekend and want to meetup and talk to us and other Crazyflie enthusiasts drop a line in the forum. The meetup will be somewhere in Berlin so do not hesitate to join even if you do not attend the Maker Faire. We will announce the exact time and place on the forum, it will certainly be on Saturday the 3rd.

On an other subject, Wolfgang, from USC, is having a talk at the IROS conference. He is going to present his research on Mixed Reality, where one of the platforms he’s using is the Crazyflie 2.0. We have visited Wolfgang’s lab and University before the Maker Faire Bay Area and we where really impressed, they are doing great research. Here’s the info on the talk:

Event: International Conference on Intelligent Robots and Systems (IROS), Congress Center Hamburg, Germany
Talk: “Mixed Reality for Robotics,” October 1, 12:20 – 12:35
Room: Saal A4
Abstract: link

Getting ready for Maker Faire New York

2015-09-22 | Marcus | Leave a comment

Last week and this week is busy with preparations for the New York and Berlin maker faires. Since we will be in the Seeedstudio booth we don’t have the same space as at the Bay Area Maker Faire, so we had to rebuild our “fly-cage”. The new specs are 1.7 x 0.7 x 0.7 meters. This is the area the Crazyflie 2.0 should be able to fly in for a full charge without touching the sides on the net.

We don’t have any special plans during the faire, except for flying during the day. So if you feel like meeting up, having a beer and getting lost in various technology discussions then leave a comment or drop us a mail.

The autonomous flying rig we used in bay-area was using the Kinect 2 sensor. This new rig is only using a standard webcam which is cheaper and easier to manage (ie. we do not need a Windows computer anymore). We are attaching an augmented reality marker on the top of Crazyflie and the image processing is mostly done by the ArUco library. ArUco is detecting the position of the Marker in 3D and the position is sent via zeromq to the controller. We used the same controller code as for the Kinect, we just had to tune it a bit better to keep in the smaller space. Then the controller is sending pitch/roll/yaw to the Crazyflie client setup to have a ZMQ as input device.

CPBrmPrUAAAKkEj

If you want to build the same cage then here’s a list of the parts:

Some kind of net (we used normal fishing net)
Fishing line (to tighten the cage)
Aluminium beam (for tents)
These 3D printed parts
Webcam with standard camera attachment (we use Logitech C920)
Camera attachment screw

We are in the process of cleaning up the code for the webcam. It will be pushed on Github and we will document the build on the Wiki.

CI server and builder image

2015-09-14 | Kristoffer Richardsson | Leave a comment

We have decided to use Travis for continuous integration builds of our open source repositories. Travis is automatically building the code on all branches and pull requests, which gives all developers that wants to contribute to the project, the possibility to see that their code passes the build. The current status of the latest build on the main branch, is visible through the icon in the readme in github, or on the Bitcraze page at travis.

The projects we have added so far to travis are written in C or python. The C projects for instance, must be compiled with special compilers for the processors used in the crazyflie which adds some extra complexity. We have created a docker image (bitcraze/builder) with the tools needed, to make life easier for developers. If you use the image when developing, there is no need to install tools locally, and the same image is used in travis builds, so you know you will get the same results as the CI-server. This also removes the problem of tools with different versions (and results) in the development- and build environment.

To use the image you can for instance type

docker run --rm -v ${PWD}:/module bitcraze/builder make

Event though it is awesome to be able to create a well known build environment through a docker container, we feel that too much typing is needed to execute a simple make. To solve that problem we are looking at the possibility of creating a toolbelt that will handle that for you. More information on that later on, for now developers will have to find their own solutions through scripting, aliasing or other means.

Obviously you need Docker to use this image. If you have not tried it out yet, take a look at www.docker.com.

We are aiming for automated testing of our code, and even though we have a lot of work to do, we have taken the first baby step. For the moment, firmware projects are simply compiled and linked to ensure that the code is coherent. Projects that support both crazyflie 1 and 2 are built in both flavours to avoid problems for developers that might only use one of the platforms. The python client project is only checked for PEP8 compliance, but we are looking at how to unit test. Any input from the community is welcome!

Happy hacking!