Posts on Jens Petit

Anki x Medizinstudium = ?

Tue, 14 Jul 2026 00:00:00 +0000

Wer in den letzten zwei Jahren etwas Zeit mit mir verbracht hat, wird wahrscheinlich mitbekommen haben, dass ich ein sehr intensives Verhältnis zu dem Computerprogramm Anki in Verbindung mit meinem Medizinstudium entwickelt habe.

Anki ist der de facto Standard für das Auswendiglernen von großen Mengen an Fakten. Das Programm ist eine digitale Lernkartei, die einem das Ordnen und Hervorholen einzelner Karten abnimmt. Die wissenschaftliche Basis dafür ist das Prinzip “Spaced Repetition”. Ich will hier gar nicht genauer darauf eingehen, was das ist, denn es existieren einige tolle Texte und Bücher über “Spaced Repetition” und Gedächtnistraining im Allgemeinen. Hier eine (unvollständige) Liste mit empfehlenswerten Ressourcen:

36 Grad und es wird noch heißer

Sun, 28 Jun 2026 00:00:00 +0000

Es ist heiß, viel zu heiß. Die vergangenen Tage waren eine Hitzewelle wie ich sie in Deutschland so noch nicht erlebt habe. Menschen flüchten sich in klimatisierte Innenräume. Der Straßenbelag platzt auf und bringt so jeglichen Tramverkehr in Leipzig zum Erliegen. An vielen Messstationen wurden ein neuer Spitzenwert gemessen - jenseits der 40 Grad. Und das, obwohl die Messreihen zum Teil bis ins Jahr 1824 zurückreichen.

Auch wenn die Auswirkungen schon jetzt frappierend sind, habe ich vor allem Angst vor einer Zukunft, in der das was wir jetzt erleben “normal” ist. Wie wird dann wohl erst eine Hitzewelle in 30 Jahren sein? Die Modelle sagen dafür Temperaturen um die 45 Grad in Deutschland voraus.

Which way to go?

Thu, 02 Apr 2026 00:00:00 +0000

In the last years my life has been marked by some profound changes. After studying to become a robotics engineer and earning a master’s degree, I pivoted towards medical informatics with my first job. Roughly two years ago, I finally decided to change my career entirely. Now I am back at university and studying Medicine to eventually become a doctor in a few years (hopefully).

Writing down these sentences sounds like a matter-of fact statement. But it has been a rocky path – filled with doubts, hesitation, and also grief. When people learn about my career change, they often promptly ask me why. Usually, my answer goes something along the line of “I didn’t want to work in an office anymore.” This is not a false statement. But it conveys only a very limited fraction of my true motivation and feelings. The honest answer goes way deeper.

Demokratie ist mehr als wählen gehen

Fri, 27 Sep 2024 00:00:00 +0000

Ich bin aufgewachsen in einer Welt, in der politischer Einsatz oftmals belächelt wurde – wer wirklich etwas ändern will, wird Ingenieur oder gründet ein Technologie-Start-Up! Heute denke ich darüber anders, denn die wirklich wichtigen Fragen unserer Zeit sind politische oder gesellschaftliche.

Was ist ungerecht, was gerecht? Wie wollen wir zusammenleben? Was sind die Werte, die wir in unserem Bildungssystem vermitteln wollen? Wollen wir überhaupt Werte vermitteln? Wie ermöglichen wir eine gute Mobilität für alle? Wie sieht ein gutes Gesundheitssystem aus?

The Human Energy Scale

Tue, 23 Apr 2024 00:00:00 +0000

Enna viewed from the south in central Sicily. It is a steep 240 meters ascent to the top of the hill where the old city is located.

In January and February, I cycled around Southern Italy for three weeks. I completely relied on the power of my body to move me and fifteen kilograms of luggage around. One day, while dragging myself up the steep ascent to Enna, a famous hilltop city in central Sicily, I was overtaken by several trucks. They would rush by with roaring engines, carrying roughly 500 times the amount of luggage that I had on my bicycle. But still, they easily climbed all the way up, dropping out of sight after the next turn. What a stark contrast. To carry that amount of cargo I would need 500 round-trips on my bike. It would take me a month with around sixteen daily trips to do the same thing the truck achieves within ten minutes. That’s insane. Energy is so cheap and abundant that we don’t even think about it. And such energy use is not an exception. Every day trucks go up to Enna to deliver such mundane things as bottled water.

Does Capitalism Require Economic Growth?

Sat, 30 Mar 2024 00:00:00 +0000

If we don’t run and constantly change, we are left behind, loose contact, are outdated. Our friends have moved on and life passed by us. The automatic staircase has pushed us into the closet.

– Hartmut Rosa in this article

Recently, the news are full again of concerned articles about the state of the German economy. Apparently, we live in a world where the slightest signs of economic stagnation cause collective anxiety. Why is that? It is even more astounding as economic growth measured as the Gross Domestic Product (GDP) has a deep connection with the climate crisis. Looking at the chart below the correlation is hard to deny.

Cycling in Southern Italy

Tue, 27 Feb 2024 00:00:00 +0000

Before taking up a new job, I wanted to get out of the daily grind for some time. As I like cycling and have done memorable trips in the past, I decided to go for a longer (roughly one month) cycling trip again. My destination was southern Italy because this is well connected to Germany via trains, offers relatively mild weather in winter and seemed like a diverse and beautiful place.

A Future for Everyone

Sun, 07 May 2023 00:00:00 +0000

This text was written from a German viewpoint.

Even if our daily lives are not yet gravely impacted, we as humanity are standing in front of an existential threat. Our climate is warming rapidly. Technical progress combined with our standard of living have put us on a path to climate breakdown.

When I was twenty, my take on the climate crisis was “we will figure it out along the way”. I had the belief that with some kind of invention we would be able to pull around. Furthermore, the scenario did not sound so serious to me yet.

Eine Zukunft für Alle

Sun, 07 May 2023 00:00:00 +0000

Auch wenn unser Alltag in Deutschland noch nicht lebensbedrohlich betroffen ist, stehen wir als Menschheit vor einer existentiellen Herausforderung. Unser Klima verändert sich schneller als je zuvor, maßgeblich verursacht durch technische Errungenschaften und unseren Lebensstil.

Mit Anfang zwanzig habe ich das Thema mit “wird schon irgendwie” abgetan. Ich war der festen Überzeugung, dass wir mit einer technischen Innovation schon noch die Kurve kriegen. Außerdem könne es doch gar nicht so schlimm sein, dachte mein damaliges Ich.

The Right Pan

Fri, 31 Mar 2023 00:00:00 +0000

Cooking is one of my favorite activities. It combines creativity, technique and it is a social event. On top of that, there is a tangible outcome which hopefully fills your belly. I regularly invite friends over to cook and eat together.

I have strong opinions on the right cookware. A centerpiece of each kitchen is a good pan. This means for me that the pan

is durable. I want to buy a pan once and use it a lifetime.
is easy to use. Cooking is an everyday activity and therefore all tools involved should not require doing extra rounds.
heats up evenly. The entire pan surface gets hot and not only certain parts.
is able to brown the ingredients. When I put stuff in a pan I usually want to achieve some kind of browning. A high heat capacity helps here.
has non-stick properties.

When you are looking for a new pan, those are usually the options in order of popularity:

On Wise Tool Choices

Thu, 02 Feb 2023 00:00:00 +0000

You like to cook. At some point your knives are becoming dull. If you don’t want to continue working with dull knives, you need a sharping tool.

There exist thousands of sharpening tools out there with two of them being:

Grinding Stone

Electric Knife Sharpener

Let’s compare those two in a couple of categories.

Grinding Stone

Simplicity: It’s a stone. I don’t think it gets any simpler than that. I think the word repair does not even make sense.

My Software Setup

Wed, 27 Apr 2022 00:00:00 +0000

This post gives a quick overview about the software I run on my PCs. In general, I am looking for keyboard centric tools which follow the UNIX philosophy (doing one thing right). Ideally, the tool integrates well into the terminal because that is where I spend a lot of my computer time - besides the browser maybe.

Operating System

Arch Linux.

I was an Ubuntu user before but switched to Arch Linux since some years now. The rolling release models gives me access to the latest software and I only rarely have any stability issues. Arch also allows me to run my own customized desktop experience without any pre-installed other packages. Additionally, the AUR is a great resource for additional packages.

My Hosting Setup

Mon, 11 Apr 2022 00:00:00 +0000

Since some time now, I am running my own private server with a couple of different services. The website which you are currently reading is also hosted on this server. I want to give a short overview about the technical background and summarize some of my experience from the last years.

Hosting Provider

When I started, I was using Netcup but switched to Hetzner since a couple of weeks. In general, I was looking for a hosting provider with Linux root servers located in Germany. Ideally, the company would run their servers on renewable electricity and have a fair price.

The DIYary

Sat, 27 Nov 2021 00:00:00 +0000

I have added a new subsection to my webpage which acts as a journal for any DIY-related topics. Me and some friends will add failures as well as successes from our daily lives to it. Take a look here.

Technical Background

As I wanted to make contributing to this “blog” as easy as possible, I created a telegram chatbot. As an activated contributer, you can simply talk to the @diyary_kg9_bot. It will guide you through creating a new blogpost.

Improving Efficiency in X-Ray Computed Tomography

Tue, 29 Sep 2020 00:00:00 +0000

The final project of my studies was the master’s thesis. It has the rather long title “Improving Efficiency in X-Ray Computed Tomography Using Compile-Time Programming and Heterogeneous Computing”.

Specifically, my task involved the open source software elsa which is developed at the computational imaging and inverse problems group at the Technical University of Munich. As I have enjoyed my involvement in Free and Open Source Software before, most notably with MoveIt, I was happy to again contribute to a larger public project.

Google Summer of Code 2019

Sun, 01 Sep 2019 00:00:00 +0000

I participated in the 2019 edition of Google Summer of Code. I was lucky to work with great mentors on MoveIt, which is part of the Robot Operating System (ROS). For more details, see this blogpost.

Remote Controlling the Robot with a Gamepad

Fri, 05 Apr 2019 00:00:00 +0000

In this post, I want to give a quick overview how you can remote control a small mobile robotics platform with a game controller. We will use the joy package of ROS to have the device publishing ROS messages. The necessary steps are described in “Setting up the Joystick” in the teleop ROS tutorial. I will quickly summarize them here.

Controller Setup

Plug in your controller and check if its available with

Building a mobile robotics platform with LEGO

Wed, 03 Apr 2019 00:00:00 +0000

As I had an old LEGO NXT set lying around at home, I decided to set up my little mobile autonomous robotics platform with it. The nice thing about LEGO is that I can quickly change anything I want without having to drill, cut or glue. Its fun and and it remembers me of my youth when I was building huge LEGO models for hours with a friend of mine.

Compiling and Running your first ROS program on the Beagle Bone Blue

Sun, 31 Mar 2019 00:00:00 +0000

This is a follow up post to the introduction to ROS and the Beagle Bone Blue (BBBL). I will guide you through compiling your first own ROS node which contains some functionality of the robotcontrol library. This library is specifically made for the BBBL and enables the robotics functionality of the board (I/O ports, I2C, PWM, UART, etc.).

It usually comes with the preinstalled images if you followed the previous post. Otherwise, you can install it with

Formation Control of Quadrocopters

Fri, 22 Mar 2019 00:00:00 +0000

See github for code and my thesis as a pdf.

For my bachelor thesis, I had the opportunity to work for six months at the Namerikawa Laboratory at Keio University in Tokyo, Japan. The contact came through my professor Oliver Sawodny at the Institute for System Dynamics at the University of Stuttgart where I did my undergraduate studies. The lab focuses mainly on distributed control topics in the field of smart grids but also with agents such as drones

Mining Public Transport Data

Fri, 22 Mar 2019 00:00:00 +0000

See here for the code.

During the summer semester 18, I had the opportunity to take part in the practical course ‘Large-scale Machine Learning’ offered by Prof. Guennemann at TUM. In my team, consisting of four people, we worked on mining public transport data in Munich provided by the company running the buses and trams (MVG).

Almost every household in Munich is located within 400 meters of an underground or tram station or a bus stop. The resulting network adds up to more than 587 km of routes for buses and trams only, which are served by 461 vehicles that stop approximately 345,000 times a day and log their position and status every few seconds.

Who needs a second screen?

Mon, 04 Feb 2019 00:00:00 +0000

A programmers perspective

For a long time, I was a strong advocate of a two screen setup whenever I could. Although I still see some benefits in having more real screen space, I have changed my general attitude. The reason for this is that having virtual workspaces gives me a very similar experience. And this wherever I want.

As a student, I am only rarely working from the same place. Sometimes I code at the university, sometimes I am sitting at a friends place and another day I am somewhere on the road. If you are comfortable with your virtual workspace setup nothing hinders you from coding with 100% efficiency because the only thing you need is your laptop. In the past, I was pretty frustrated when I could not work at home where I had my second large screen. However at some point, I realized that I could be as efficient using virtual desktops.

The Handtracking Robot

Mon, 26 Nov 2018 00:00:00 +0000

During the winter semester 17/18 I took a course called “Multi-sensory Based Dynamic Robot Manipulation” at the Institute for Cognitive Systems at the Technical University of Munich where I am currently pursuing my masters degree in robotics.

The course was one of the best I’ve had in my university career which is mainly because Mr. Dean, our lecturer, did such a great job. It was sometimes painfully hard to get the homework done because I had to learn so many new things at the same time. Coding in C++, using Ubuntu and ROS, control theory, robot dynamics and kinematics… The course had a final project in the end which I did together with two other people in a team.

My high school robotics days...

Tue, 10 Apr 2018 00:00:00 +0000

I was lucky that in my high school we had a Robotics Group led by a passionate physics and math teacher. For me it was an awesome experience which defined the last four years of my time in high school.

As a team we participated in the RoboCup Junior Soccer competition, starting with simple LEGO NXTs in 2007 and finally becoming German Champions in 2011 with highly sophisticated custom machines. Below are some pictures which show the evolution of our project. We built robots that played 2vs2 soccer on a table sized playing field.

Getting Started with the BeagleBone Blue, Ubuntu and ROS

Thu, 08 Mar 2018 00:00:00 +0000

Through a university course on robotics I got introduced to the so called Robot Operating System (ROS). And it got me hooked!

The Robot Operating System (ROS) is a set of software libraries and tools that help you build robot applications. From drivers to state-of-the-art algorithms, and with powerful developer tools, ROS has what you need for your next robotics project. And it’s all open source.

After building football robots during my high school days, this was a great opportunity to gain some more hands-on experience.