niemueller.de

Setup git tracking branch for existing branch

Sat, 20 Feb 2010 12:59:08 +0100

Something that I did many web searches is how to setup up tracking of a remote git branch for an existing local branch. That regularly happens for example if I start with a local topic branch, and then push it to the central repository. Now, git does neither automatically setup that this (new) remote branch should be tracked for the local branch nor did I find a convenient command or argument to do so. So here is what is required, assuming that the remote repository is named origin, the local branch is topicbr, and the remote branch is timn/topicbr, and you are in the local git repository:

git config branch.topicbr.remote origin
git config branch.topicbr.merge refs/heads/timn/topicbr

.
It's that easy and now I have a place to look it up next time I need it...

Aldebaran Workshop 2010

Sat, 06 Feb 2010 10:18:06 +0100

I'm currently attending the Aldebaran RoboCup Workshop. It has its interesting points but obviously there is a lot of old stuff for new teams. You can follow me on twitter for fresh info on the new version of the Nao.
Currently there is a talk about the Nao motion module. Besides that I'm setting up the OpenEmbedded tool chain, again.

Conquering the N900

Mon, 04 Jan 2010 00:57:30 +0100

Last week just at the end of the last decade (happy new year everybody btw) I got a Nokia N900 with the Linux-based Maemo 5 operating system. I have had an N810 for more than a year and was very pleased with the device, especially because I can write "normal" programs, i.e. programs running on Linux with the APIs I already knew from desktop apps. For example Fawkes is running just
fine on the device!

My first impressions after using the N900 are positive. It is still beta around the edges but it gives you full control over your device, including root access which just feels right. Here are some notes which might be useful and which I might need again.

Content Transfer from old Symbian (N76 -> N900)

My last cell phone was a Nokia N76. It has agglomerated quite some data like contacts and calendaring info over the last couple of years. So how to transfer? On the last Windows installation we have in the household (a partition on a laptop we usually boot once a year for reporting taxes), from the
last transition there was still a Nokia PC Suite installation. I figured I should upgrade it to work with the N900. Nokia nowadays recommends the Ovi Suite so I thought I'd give it a try. It failed already with the N76. After successfully connecting it would say that some operation was still running no matter what I tried to do. The N900 was not even recognized. So back to the PC Suite. It copied the content from the N76 just fine with the Content Copier (which I used last time for transferring from the 6230 to the N76). But for the N900 this is not supported. The only thing it can do is synchronization - and to synchronize the calendar you need either Microsoft Outlook or Lotus
Notes. That sucks! So the only thing I could transfer were the contacts using this method.

Later the day I remembered that there was some synchronization feature directly in the phone. I looked it up in the N76 and with this I was able to copy my calendaring data to the N900! This might work with other models also having the Switch application. Here is how if you want to do this as well. First open the application in the menu Tools -> Utilities -> Switch (on German phones: Programme -> Dienstprogr. -> Austausch). Then select Options -> Synchronize and follow the instructions on the screen. Turn on Bluetooth on your N900 and make it visible and allow pairing with your old phone.

You should be able to initiate this from the N900 in the Settings -> Transfer & sync. app. I haven't tried it this way around though.

Extras repositories

Additional software can easily be installed from the Maemo Extras repository, which is enabled by default. It already contains many interesting applications, but especially at the moment there is quite some software still waiting in the Extras-testing and Extras-devel repos.

Although officially discouraged, I have enabled the devel repo (I hope I kinda know what I'm doing, we'll see). It contains quite some packages that haven't made it through the full testing, yet. Among these are the Bluetooth Dial-Up Networking profile to dial-in with the phone from my laptop, a nice flashlight app, the Personal Data Plan (show amount of transferred data) and Personal IP Address (show current IP) widget and the packages for (developer) PC connectivity.

Cisco VPN GUI

Our university provides a Cisco VPN. To use this I have installed vpnc and vpngui from the Extras-devel repository (packages). After a small patch (bug #4184) it works like a charm and I can use the VPN.

Changing the host name

Since I'm using mDNS-SD via Avahi a lot to communicate with the robots I wanted to change the host name to something more personal. The host name announced via Bluetooth can be changed easily, but I didn't find a way to change the real host name. So I used the root access to set a new host name in /etc/hostname. Note that you also need to modify /etc/hosts to add the new host name as name for the localhost address. Otherwise the N900 gets too slow to do anything with it. Then a reboot and the new name is active.

Creating a connection from a laptop

For Bluetooth DUN support you need to install the "Bluetooth Dial-Up Networking" package (requires Extras-devel repository at the moment, reboot after installation to finish installation). Afterwards creating a connection from a laptop via the N900 works as with any other phone. On Linux (Fedora 11 in particular here) you can use the Bluetooth Manager (package name is blueman) to setup the device as DUN Adapter (right click and choose "Setup"). Afterwards you can create a broadband connection via the NetworkManager (right-click, edit connections, create mobile broadband connection). If you are as lucky as me your provider data is already available for selection. Afterwards click on the NetworkManager icon and the connection name to establish the connection. Next time in the Bluetooth Manager you just need to right-click on the N900 and select "Connect to: Dial-Up Networking" and then the connection in the NetworkManager. The only thing that I'm missing is that the N900 will not indicate the laptop connection in the status bar, which I find irritating.

And now after some days off back to real work...

Maemo 5 SDK on Fedora 11 x86_64

Mon, 07 Sep 2009 00:03:16 +0100

The new Nokia N900 has been presented with much fanfare featuring Maemo 5. I'm the happy owner of a N810 and it was the original reason to write the LaserGUI for Fawkes. I'm really looking forward for the device. I planned to get a new mobile anyway and wasn't sure whether to go for the N97 or an Android phone. Now I'm eagerly waiting to get a N900 into my hands.

The last time I developed for Maemo I had setup a 32bit virtual machine with Fedora to run the development environment. But this is clumsy at best. It consumes a lot of extra resources (especially RAM) and the virtual environment cannot do my native full resolution. This time I wanted to try the SDK for the new Maemo version and installed it natively on my x86_64 Fedora installation, which works just fine. Here are some notes that might be helpful if you want to do the same. The notes are for the Maemo 5 SDK, Beta 2.

You need the basic 32bit libraries to install the environment. I didn't run into anything that was missing, so I guess a basic 32bit environment is sufficient.

There is a very good installation manual for the SDK. First download the scratchbox and sdk installer scripts referenced in the manual. To install on x86_64, you need to make two changes. First you need to add the kernel parameter

vdso32=0

by adding it to the lines beginning with "kernel" in /etc/grub.conf. For this to take effect you need to reboot (before you start the installation). Secondly you need to enable the "force" mode without enabling .deb installation. This is only possible by adding the script. For this add "__force=yes" around line 311 (where the s parameter is handled). The section should afterwards look like this:

s)
   __type=tgz
   __force=yes
   __scratchbox=$OPTARG
   ;;

Now you are ready to install scratchbox. For this execute the scratchbox install script as root like this

sh maemo-scratchbox-install_5.0beta2.sh -s /opt/maemo-sdk-5b2/scratchbox -u tim

and follow the instructions on the screen. This will install the SDK to /opt/maemo-sdk-5b2/scratchbox and add the user tim to the allowed users. This must be your user name on the Fedora system. Then execute the SDK installer not as root, but as normal user and follow the instructions. There was nothing special I had to do, just do

sh maemo-sdk-install_5.0beta2.sh -s /opt/maemo-sdk-5b2/scratchbox

Now Maemo is installed and after one slight installation and/or fix you are ready to go. The current version of Xephyr in Fedora is broken. It was only in version 1.6.3 where patches have been applied that fix segfaults when pressing keys. This version is available in the updates-testing repository. I did not experience any problems, your mileage may vary. To update the package do

yum --enablerepo=updates-testing update xorg-x11-server-Xephyr

replace update with install. I have actually updated all xorg-x11-server* packages. I'm not sure if this is necessary. Works fine for me so far.

You might want to read Thomas Thurman's tutorial series about developing for the N900.

You can install the Maemo 4 SDK similarly. In the scratchbox install script uncomment the "exit 1" line by prefixing it with a hash (#) to eliminate the i386 check. You need the same vdso32 parameter and the updated Xephyr. I recommend choosing different directories for the two SDKs, as they use different versions of scratchbox.

Trac and Django packages for CentOS 5.3 and Fedora 11

Thu, 20 Aug 2009 01:16:28 +0100

The Fawkes website is built using the Django web framework and it is run off of a virtual CentOS machine. We wanted to use the latest version of Trac, as it has some nice new features and most of the development of Trac hacks is done for 0.11 by now. After a short conversation with Jesse it became clear that Trac in EPEL5 will remain on the 0.10 code base (upgrade involves manual work on each Trac instance, plugins usually need upgrades).

Therefore I have packaged Trac 0.11.5 for CentOS 5.3 myself based on the existing package and thought I'd share, maybe someone else wants to use the newer version on CentOS. It includes a bunch of plugins (in particular a patched trac-git-plugin to work with Python 2.4). Many of these plugins and macros are not included in Fedora/EPEL. Among them is the popular account manager plugin. Is anybody interested to push a package through a review and maintain or co-maintain it? I do not have the time to maintain them on my own, but maybe someone else is interested?

Additionally I have packaged some Django apps, namely django-reversion, django-evolution, django-robots and sorl-thumbnail. Again, is someone interested in pushing it through a review and (co-)maintain it?

You can find the RPMs and SRPMs in a small repo on fedorapeople.org. The el5 tree also contains an updated doxygen and git (git being required by the trac-git-plugin). Either download the specific RPMs or you can use timn.repo to tell you yum about it (enabled the required repos). The Trac and Django packages are noarch packages. For the newer doxygen and git packages I have only x86_64 versions at the moment. Rebuild the package by yourself if you need it for a different arch.

Fawkes released!

Fri, 14 Aug 2009 14:42:24 +0100

It's finally done, after almost three years of development we have released our Fawkes Robot Software Framework as Open Source Software! You can read more about and download it at http://www.fawkesrobotics.org. It's a component-based software framework to operate robots in uncertain environments. It is designed to work on multiple robot platforms in different domains (currently robot soccer and service robotics). Currently we employ the robot software frameworks on three different kinds of robots in two teams (see for instance the AllemaniACs team description on the Fawkes website).

Currently Fawkes works on Linux and FreeBSD. If you want to run it on Linux I recommend using Fedora, as it provides all the required software packages out of the box. You can find a yum command to get 'em all on the FawkesOnFedora wiki page. The next milestone will be to add support for system-wide installation. That will allow us to provide package repositories for even simpler installation. Currently Fawkes is build and used in a self-contained tree, which is a very flexible and easy setup to start developing for the robot without special privileges (cf. DeveloperGettingStartedGuide)

At that point we can then use the software to build an easy to use simulation environment for example for the planned Fedora Robotics LiveCD, integrating Fawkes with the Player/Stage/Gazebo simulation environment and providing the Fawkes Lua scripting facility to make the robot operate in the simulation! It's still a way, but today we made a huge step towards this goal. Now is also the time to revive the Fedora Robotics SIG, which hasn't been active for the last couple of months due to people being busy with other stuff.

C++0x no more

Fri, 24 Jul 2009 19:57:48 +0100

I have read a couple of posts lately about the removal of Concepts from the upcoming C++ standard. I started with part 1 and part 2 of a report from the last committee meeting in Frankfurt by Michael Wong. He was in Aachen this week to give a talk about the new features. Unfortunately I missed it, reading the announcement poster and parsing the start time and not the end time is, you know...

Lately Bjarne Stroustroup wrote an article about the decision to remove Concepts from C++0x. And from what I've read it seems we shouldn't be too sorry about the removal. There is still a lot of new stuff that one can get excited about and that should make our live easier. It'll be more likely C++1x now as he states.

However, I wonder when we will see enough coverage in the features and when all target platforms and systems have been upgraded so that you can actually use those features... We are still using Fedora Core 6 machines regularly (due to missing propietary driver updates). Also for the Nao currently GCC 4.2 is used, as is on FreeBSD 7.2. So we'll have some time...

I'm back

Sat, 18 Jul 2009 01:51:42 +0100

For several months I had suspended many activities, including writing blog entries, for working on my thesis and writing software. But now I'm back. A lot has happened during this time in my little part of the universe. I have submitted by diploma/master thesis "Developing A Behavior Engine for the Fawkes Robot-Control Software and its Adaptation to the Humanoid Platform Nao, and as it seems it worked out nicely - and the code will be released soon.

I have put a lot of effort in the past months into our (AllemaniACs RoboCup Team) robot software framework called Fawkes. It provides the basic infrastructure and utilities required to write robotic software and applications. I happen to be the architect and main developer of Fawkes, with help of several fantastic people that have put code and ideas into the project. Fawkes is based on experiences we made with our former software framework RCSoft. It had shown it's age back in 2006 and basically was our "one to throw away". Currently I'm preparing all the infrastructure around the project (website, public source code repository etc.) for a public release as Open Source software - finally. This was always in my mind and for each line of code we copied from RCSoft I contacted the old authors if the files were missing a license header, now we have a fully GPL'ed package. Stay tuned, it's just a matter of days now.

There were two RoboCup events that I didn't blog about - but we've been there! First was the RoboCup German Open 2009 in Hannover. There we participated with our still-somewhat-new mid-size robots and with the Nao humanoid robots in the Standard Platform League (SPL). In the latter we participated as team ZaDeAt consisting of members from the University of Cape Town, South Africa, us at the RWTH Aachen University, Germany and from Technical University of Graz, Austria (there for ZaDeAt, ISO country codes). It was a pretty experimental event. Last year the Naos were merely able to keep standing and walk a little, this year we saw some real game play. Because a few software components were missing, we couldn't play up to the level we had imagined and dropped out already after the first round robin. But I could do some last evaluation of the behavior engine and agent program I wrote for my thesis, and of course the port of the software to the Nao robot. So personally this event returned what I needed. I also did a lot of refereeing, including the final which was won by the B-Humans from Bremen. For the mid-size league this was the first real field test. We couldn't do a lot of testing back at home, because we did not have a suitable environment. Getting enough space in the university is tough, so the best we could get was less than half the size of a robot soccer field. Then we had to buy a special "flame resistant" carpet (because the location happened to be the main entrance lobby). Unfortunately this one was so soft and thick that the friction was so high that the robots could barely move and the motors were overheating quickly when they moved. So in Hannover we were mostly busy doing live integration experiments and trying to get the robots running, somehow. But at least they could move on the tournament carpet. The lighting conditions were pretty bad in the exhibition hall were the games took place. Therefore many teams had problems with the vision (especially in the SPL), which included us. In one of the Nao games we literally sent one of the team members outside to check the weather. Depending on the state of clouds and sunshine we had to decide for a particular color calibration...

RoboCup 2009 in Graz was also fun, besides the cold I acquired on the very first day... We drove there by car in about 11h. After we arrived we found out that on Sunday nights all restaurants are already closed (in Graz) and that even with rain jacket you can get damn wet. We participated in the RoboCup@Home league and with the Naos again. Due to missing commitment and focus by the Nao team in the time around the Hannover event I pulled out of much of the Nao development work (although this has been a major part of my thesis) and concentrated on the @Home competition as part of the AllemaniACs team. We are kind of a tournament team, meaning that we tend to do much of the required work and final testing during the event. It's an awesome team with brilliant people and on those occasions we close ranks and work hard and get a lot of stuff done. RoboCup events are basically our development sprints. So in Graz we got to note the time we missed in Hannover (where we did not participate in the @Home league, because we did not have enough people for three leagues and it was the mid-size department's turn). But we anticipated this problem and decided to use this event to retire parts of the old RCSoft in favor of Fawkes. Thanks to the AllemaniACs for pushing Fawkes with this event. It helped a lot and showed what the software is able to achieve. The month before the event I spent my time writing communication plugins to share data between multiple instances (the @Home robots have two or three computers, while the robots up to now always had only one) and with the old software framework (we have too much software in the old framework to port it all at once). Additionally I wrote several plugins and additions for access to basic hardware, writing (Lua) scripts to make them accessible in the behavior engine, calibration tools and a lot of stuff that I discovered to be missing during the integration of all this. We also developed a pan-tilt unit to move the camera on the top of the robot literally in the two weeks before RoboCup. Masrur wrote a new leg tracker that detects and tracks humans via the laser range finder. Worked nicely, after a few days and nights of on-site hacking :-)

During the event it went pretty well. Of course we had our problems and discovered bugs that required fixing. But we had some interesting runs (find details on the AllemaniACs' page) and in the end became 6th out of 18 teams. We had a fair chance to get into the finals (last 5), but in the end three bugs (spreaded over both software systems) cascaded into failing the PartyBot test, leaving us with about 500 points (out of 2000 you can achieve in this test) missing. But I think we did it again and showed something truely new: two fully autonomous robots that communicate with each other to solve a task cooperatively in the home environment. There were several teams with a second robot, but none had two full-fledged robots interacting with each other in the arena. Closest come the Homer from Koblenz, where the main robot remotely controls a Roomba. The tests did not go absolutely smoothly, but the robots showed interaction and tried to do their job. Better next time... For Fedora Planet readers it might be interesting to note that both robots were running Fedora, one FC3 and the other FC6 and F-10. Yeah, I know these are very old versions, but we used FC6 due to some drivers not available for newer versions and FC3 is on the secondary robot, we screwed together (again) the week before the event, and I compiled the required packages etc. on-site. So there was just no time to upgrade.

On a related note I presented a poster for our paper about a "A Lua-based Behavior Engine for Controlling the Humanoid Robot Nao", which describes a environment to write small robot behavior entities called skills, which are modeled as hybrid state machines, can be hierarchically structured and are exposed as simple functions to the higher level control program (i.e. agent).

Besides all the exciting stuff I have also moved this very server the page is served from. It used to be a Pentium III rack server with Red Hat Linux 7.3 (pimped with some self-made update packages) provided generously by a company I worked with. Thanks guys! Now this runs CentOS 5.3 in a Xen virtual machine on another CentOS. And since I wrote my own stuff to manage the website early this decade it was quite a shock for this creepy code to go from an old PHP 4.1 to 5.2. I just fixed the application today to be able to blog again. For the Fawkes website I'm experimenting with Django and I like it. Maybe when I find some time I'm going to port my website as well. But first let's see if I manage to update this blog more often...

This picture shows all RoboCup@Home robot from this year's competition. All photos in this entry were taken by Masrur Doostdar of the AllemaniACs.

UniMatrix 1.2 released

Sun, 12 Oct 2008 23:56:33 +0100

After three years I have released UniMatrix 1.2 yesterday. It fixes two long-standing bugs. UniMatrix is a program for Palm OS that allows for managing courses, classes and exams on your handheld released under the GPL.

Although time is short while playing around a bit with Maemo I got interested again in handheld programming and setup the Palm tool chain once again. That procedure feels more arcane than last time. Have to write that down when time permits. It's awesome though that you can have a free tool chain, besides the SDK containing the system libs to link against and the header files.

Maemo is an interesting platform. I'm still playing with it but most of the application I wanted to port needed only a very few changes. Though I'm disappointed that basically all Gtkmm-related libraries are missing for the arm target by default. Currently building a whole bunch of packages and dependencies...

Back from South Africa

Thu, 25 Sep 2008 11:39:54 +0100

For the last two weeks I've been in South Africa to work with our fellow researchers and present our robots.

For our participation in the Standard Platform league with the Nao robots we are cooperating with the University of Cape Town (UCT) and TU Graz. I've been to Cape Town to work with our fellows from the Robotics and Agents Research Lab at the UCT. I gave presentations of our robot software framework that we've developed during the last two years to get more students interested. We discussed the future of the project and how to proceed from the current state. Since we have to robots for not even half a year a lot of work remains to be done. I'm confident however that with joint forces we can achieve a good result for next year's RoboCup event.

Along the way we installed Fedora on two Mac Laptops. Once as a virtual machine and once via boot camp. Both worked just fine and allowed for efficient usage of our robot software framework. Although Slackware and Ubuntu are more dominant in that lab Fedora is the only distro at the moment providing all required libararies out-of-the-box, as I maintain a few of the required packages. Our new robot software framework is Open Source software and we plan for a first public release around the end of this year.

After the research meating I flew to Johannesburg were we were invited by the German Federal Ministry of Education and Research to participate on the German booth at the The International Science, Innovation and Technology Exhibition 2008 (INSITE). We've been to the last INSITE as well in 2006, so we met a lot of people again that participated a second time as well. It was fun again to discuss with all the science people various topics and get to know what others are doing.

We presented one of our Nao robots and the research cooperation with the UCT. There was a second robotics booth Robotics SA sponsored by the IEEE comprised of several South African universities and research facilities showing their robots. Our colleagues from the UCT were there demonstrating their custom-made small size league robots, allowing remote control by visitors, and another of our Nao robots.

The event attracted more visitors overall than last time. Though the audience wasn't fully what we would have liked to see. There were only a few university lecturers and not as many students as we expected, although Johannesburg itself having two universities and Pretoria with another two international universities only being a one-hour drive away. Besides that we had several interesting conversations and Alex gave a short talk at the Robotics SA booth about the RoboCup idea.

Afterall I'd say it was a pretty successful trip to South Africa,xturl and a fascinating one. In Cape Town I had two days where I could meet with other students and where I saw some of the country side and I went up to Table Mountain which gave a great view over the city. In Johannesburg I had half a day were I went to the Apartheid Museum. Besides the wealth of information about recent South African history it provides it was very impressing. I went there with a friend from India. We bought tickets - and I got one for whites and she for non-whites. A guard was guiding us to the "matching" entrance. That was really weird. You then walk separated ways inside the first building only communicating through a curtain with each other. The texts are different on boths sides so you have to tell each other what it's all about. She said "ok, just get out and take the back entrance to see this picture here". Sounded like a good idea, I left the building and then... realized that you had to get up to an elevated way that guided you past the non-white exit. Just after 10 meters or so you could then go back and down to be able to get to the other side. But by then we decided to go on. A really weird experience that just felt wrong...

There are some photos from the INSITE 2008 in our gallery. We've also recently uploaded pictures from RoboCup 2008 in Suzhou, China.