Game modding with pen and paper

I have lots of good memories from youth camps. Some involve playing Donkey Kong and Mario Brothers while sitting on trees. Another classic video game was Asteroids. When I recently read an article in a German magazine about building an Asteroids clone with an Arduino and an OLED, lots of old memories resurfaced. The source code was provided, and the build was simple. As the control was used as digital, I didn’t use an analog joystick. When I gave it to the kids to play, they didn’t share the same enthusiasm that I had back then. But that’s probably because they grow up with lots more tiny computers than we had. So I wanted to involve them some more, and give them a sense of how this thing works. I don’t know how well they understood, when I explained them the concept of a pixel.
So I grabbed pen and paper, read the source code and drew the pixel art. Next, I told them they could modify the images to their liking, but still preserve the mechanics of the game. It was essentially the spaceship with one frame, the asteroid with three frames and the explosion with four frames. Seven year old Levin understood immediately, and painted his versions. For five year old Noah it might be a bit early, but he also participated enthusiastically.
All I had to do was transform their paintings back into source code and load it onto the AtMega chip. Now they were hooked a lot more to the game than before.

drive in cinema

The last time I was in a drive in cinema was about ten years ago. At the place I was in Volketswil, they no longer organize these events. So I was looking from time to time for another place. The ones I found were too far away. Then I saw an advertisement for Hinwil. It is close enough and on a TCS training area. The slope towards the screen seems to be perfect. We chose a movie that we could watch with the kids: Alvin and the Chipmunks: The Road Chip
Because we expected a ton of people, we made sure to be there early. But to our surprise only about 20 cars were lined up. So we got a really good spot in the center of the front row. They didn’t use a projector, but a huge LED wall. That was really valuable for the afternoon kids movie. We tuned the car audio to the provided frequency, and enjoyed the movie.
They had food and drinks and VIP pickups with cushions. The whole event was really well organized. I hope they had more people at the evenings so that they will also organize the event for many years to come.

Running hostile software in a container

Remember Skype, the once popular phone software? I used it a lot when we were traveling in South America, and international calls were insanely expensive. But I stopped using it when it was acquired by Microsoft, and they switched from a P2P model to centralized servers. From what I could observe, it gradually worsened from there, and I really thought I wouldn’t have to use it ever again. That was until somebody decided that we had to use Skype for Business instead of XMPP at work. There are a plethora of better alternatives. The one I use the most these days is Tox.

I use the Windows Workstation only for things that I can’t do on Linux. There is not much that falls into this category, besides VisualStudio compiling projects that involve MFC. There is Skype for Linux, but there is no official Skype for Business for Linux. So for a moment it looked like the Windows machine got a second task. But running an obfuscated malicious binary blob from Microsoft with known backdoors, that is online all the time on an operating system that can not be secured makes me uneasy. So I looked for a way to run it securely on Linux. The first thing I found was an open source implementation of the reverse engineered proprietary protocol as a plugin for Pidgin. That sounded good, but it didn’t work unfortunately. The second option was a closed source clone from They provide their own apt repository with regular updates. That’s quite good actually, if you don’t care about closed source software, and the security of your device and data in general.

I learned about docker a while back, but only used it marginally so far. This was the first real use I had for it, so I started learning more about it. Copying and adapting a docker file is a lot easier than the articles I read so far made me believe. I found a couple of sites about packing Skype into a docker container, but none for Skype for Business. So I took one of the former ones and adapted it. To use my container, just follow these easy steps:

git clone
cd docker-skype-business
sudo docker build -t skype .
sudo docker run -d -p 55555:22 --name skype_container skype
ssh-copy-id -p 55555 docker@localhost
ssh -X -p 55555 docker@localhost sky

The password for ssh-copy-id is “docker”.

Then log into sky with your credentials. You can do this every time, or you can store a configured copy of the container as follows:

docker commit skype_container skype_business

The next time, you just run it with:

sudo docker run -d -p 55555:22 skype_business
ssh -X -p 55555 docker@localhost sky

I left some pulseaudio stuff from the original container at least in the README file. I don’t intend to use it for anything but receiving chat messages. But if you want to, feel free to experiment and report back.