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.

Server down time

2015-11-16 | Kristoffer Richardsson | Leave a comment

On Thursday 2015-11-12 our web-servers were down for a few hours. Some unexpected updates in our hosing service made our storage solution stop. Unfortunately we had to restore our data from the latest backups to get the system back up and therefore lost all “new” data between 2:00 and 16:00 CET 2015-11-12. The services that were affected are the forum, the blog and the wiki. Any posts, new accounts or other user data that has been added during that period were lost. If your post/account/comment is lost, please add it again.

We are sorry about this and are working on finding a solution to avoid this in the future.

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.

Team pomodoro

2015-11-06 | Kristoffer Richardsson | Leave a comment

We are experimenting with pomodoro inspired techniques (http://pomodorotechnique.com/) in the team. What we do is that we are doing team pomodoros where we work focused for 25 minutes, without communicating. During the work periods we record all questions and so on that we need to ask, and after the period we communicate and resolve all issues that came up. We don’t do pomodoros all the time, but only when we feel that it is useful. Some days we might do a lot of them and other days none.

What we find interesting is that it has turned out that the important feature is not about NOT communicating during the work periods, but that the communication becomes more focused when we do communicate.

We have added a countdown timer widget to our dashboard to make it really easy to start by anyone.

The timer is also handy for all sort of time-boxed activities in the team.

The code for the widget is available at https://gist.github.com/krichardsson/a2c8ad556caa643f822c

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.

Role contracts

2015-10-14 | Kristoffer Richardsson | Leave a comment

There are a lot of things we need to keep track of in Bitcraze, such as customer support, production, book keeping, planing for the future, improving how we work, our servers, forum, the community, source code, new hardware, just to mention a few areas. There has been an informal distribution of these areas between the persons in the company, but it has not been very clear who is responsible. This has led to that we all worry about everything but we still miss to catch some issues. So we have two bad properties: not as good performance as we would like to have and negative feelings. So what to do?

We have decided to set up role contracts. Our version of role contracts is simply to appoint one person to each area that we feel needs continuous attention. The person that is responsible for an area is expected to keep track of what happens to that area, think about how we should improve or change, and notify us (the rest of the team) when we need to take some sort of action. That person is not expected to execute or implement, but make sure that we get it done as a team.

We will update the role contracts at regular intervalls, every month as a start, to make sure we are working with stuff we passionate about and so that we have a dynamic team.

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

Feedback

2015-10-07 | Kristoffer Richardsson | Leave a comment

For a background on the “How we work” category, see Self organizing

Next on the agenda was to talk about feedback. Feedback is the oil that keeps the team happy and enable individuals to gain insights about them selfs. Important stuff!

We talked about the self and some techniques/models that can be used to understand our selfs and others (e. g. Johari Window). We discussed how we react when we receive feedback, and what we can do to increase the possibilities that we really listen to and understand the feedback that is given to us. These insights also help us to give feedback to other persons.

The last part of this was a “recipe” of how to compose feedback for someone. Try to include the following

Observation of a behaviour
How that makes you feel
Your needs that created the feeling
Your wished of alternative behaviour

Some slides are available at Prezi

Finally we practiced by giving everyone else feedback one-on-one. We will continue to give each other feedback over the coming weeks on a regular basis – practice makes perfect.