Creating Value by Sharing Knowledge


Posted 2011.11.25
by Fredrik Leijon

During Øredev this year we decided to have a zeppelin in our booth, and to make it more fun we decided that it should be remote controlled! After a few iterations (hardware projects can be done agile too) we ended up with the following thing – an Arduino powered zeppelin that communicates with a computer using XBee and is controlled with a Wiimote connected to the same computer. The leetZeppelin was built by Fredrik Leijon (@fleijon) and Marcus Olsson (@_macke_). We think that all the gazing at the sky and half opened mouths proves that it was a huge success!

We started with a remote controlled Blimp from and as soon as it arrived we gutted the gondola to make place for the Arduino controller we wanted to use.

First version of the zepelin

First version


However, after some testing we realized it was too heavy and hard to steer so we decided to build our own gondola and ended up only using the engines that came with the Blimp kit.

The second version of the gondola had two motors that were able to change angle of the motors to direct thrust and easier steer the zeppelin. The motor mounts consist of carbon fiber tube glued to a Lego rod with a gear connected to a servo motor. Servo and the motor mount where glued to a frame of cardboard.

Motor mount zeppeline version two

Servo controlling motor direction


Motor mount

Motor mount

To be able to drive the motors in both directions (to be able to go both forward and reverse) we dismantled 2 servos and jury rigged the controllers to work as motor controllers.

Modding servo motor

Fredrik modding a servo motor


Modded servo control

Modded servo control

The zeppelin is controlled by an Arduino FIO. We chose the FIO since it has a connection for LiPo batteries and a XBee module can be mounted directly on it. To create place for the battery we used some Lego bricks for creating space between the Arduino and the cardboard frame. The Lego was glued to the frame and we used tape to attach the micro controller.

Finished gondola

Just for the lulz we added an IR Led and the code for TV-B-Gone that allowed us to turn off TVs if a secret key combination was pressed on the Wiimote. We used a slightly modified version of Ken Shirriff’s Arduino port of the tv-b-gone software.

Tv-B-Gone IR Led

Tv-B-Gone IR Led

The computer controlling the zeppelin has a Wiimote and an XBee module, the software used to control the zeppelin is written in python using wxPython. The purpose for it is to parse input from the Wiimote and send it to the zeppelin.

The computer communicates with the Arduino controller over a serial port; the XBee modules create a wireless serial link between them. To get input from the Wiimote we used the CWiid library with a python wrapper. The reason for using python and Linux was simply that it allowed us to quickly build a working solution and the Wiimote library’s for Linux works a lot better than Windows versions.

Here’s a list of the important parts used.

Hardware - Zeppelin
  • Arduino FIO
  • XBee
  • Servo motors
  • 2 x  Servo motor or motor controller
  • Motor
  • Proppeler
  • Blimp Balloon Envelope (
  • IR Led
  • Carbon fiber tube
  • Lego Gears
  • Lipo Battery – 1s 1000 mAh


Hardware - C&C



Some of the pilots

Happy pilot

Happy pilot

preflight check OK

Preflight check OK


Code Retreat

Posted 2011.05.11
by Oskar Hülphers
May 28th, 09:00 – 16:00
tretton37 office in Lund, Lilla Fiskaregatan 8A, 222 22
Developers honing their craft together. before May 22nd

How often do we as developers get a chance to practice and really hone our craft without focusing mainly on the end-result? Wouldn’t it be great to try? We thought so! That’s why, in the spirit of Corey Haines, we’d like to invite you to a Code Retreat for a full day at our office in Lund.

The purpose is for us to get a chance to practice, develop and ponder on our skills as developers, rather than learning new languages and frameworks. We aim to focus on the most basic and fundamental aspects of programming and it’s up to you to choose which language and IDE you want to use.

Attendance is completely free of charge and breakfast, lunch and snacks are included. The numbers of seats are limited though, so if you’re interested, please rsvp rather sooner than later.

Please bring your own computer, with IDE and unit testing framework ready to go, in order for us to get started as soon as possible.

We’re looking forward to a great day together. Some of us are planning to head out and grab some drinks afterwards and everyone is invited.

If you have any questions feel free to contact Oskar Hülphers, +46(0)706-735898.

We Love New Knowledge!

Posted 2011.01.18
by Martin Thern

We at tretton37 like to hang out and have fun while stilling our hunger for new knowledge. So we decided to do something fun and useful one evening every week.

It all started with our breakfast discussions that we call Tech Radar. This is an open forum where we discuss upcoming technologies that we want to know more about and that might be of value to our customers. Since Tech Radar is all about discussion, we created the concept of Code Night to be able to get more hands-on experience and get the opportunity to try out cool new technologies and ideas for new applications.

Our first two Code Nights have been all about mobile applications. Since we are  .NET developers it felt natural to start experimenting with Windows Phone 7, but we have also started to explore iPhone, Android and HTML5.

What have we learned from this so far?

Well, apart from that is both challenging and fun to make applications to fit in the small phone display, we’ve learned that this is a relaxed and fun way to learn new technologies and share thoughts and experiences.

We are now just at the beginning of the tretton37 Code Night journey, and I think that our new blog is a great way to let you know what we currently are working on, so stay tuned!

Happy coding y’all!