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HedgeDoc is a collaborative markdown editor that can be accessed via a web interface. It is practical for note-taking and for creating texts with multiple people simultaneously working on the document. Since HedgeDoc is open source, you can host it on your own server. This is exactly what I am doing. I mostly use my HedgeDoc instance to take notes and for assignments at university. Since all guides on hosting a HedgeDoc instance I found online lack important steps like setting up your own domain or creating backups, I decided to create my own guide on HedgeDoc self-hosting. In this...

Als Jugendlicher habe ich bei Aldi Talk ein SIM-Karte gekauft. Da ich damals noch minderjährig war, habe ich die Karte auf eine andere erwachsene Person registrieren lassen (mit deren Einverständnis). Weil ich mittlerweile volljährig bin, habe ich im August 2023 die Inhaberschaft an dieser Rufnummer auf mich übertragen. Da ich von Aldi Talk keine Informationen zum Inhaberwechsel online finden konnte, habe ich mich entschlossen, meine eigenen Erfahrungen in diesem Blogpost zu teilen. Aus rechtlichen Gründen kann ich leider keine Original-E-Mails von Aldi Talk veröffentlichen. Stattdessen fasse ich jeweils den Inhalt der E-Mail zusammen. Erste Anfrage (28.08.2023) Über das Kundenportal “Mein...

Projects are most fun if you can build them from broken or unused parts you have already laying around. In my case, I had some old Bluetooth headphones from 2014 where the plastic headband had broken through. The electronics still worked, but due to the broken headband, the headphones were not usable as such anymore.

In this post I will show you how to compile and install the Linux kernel from source on Ubuntu. I know that there are tons of tutorials on compiling the Linux kernel. However, while I tried many of them, none of them worked for me. I always either got error messages during compilation or the compilation terminated without error messages but failed at installation. Therefore, I decided to write down how I did it. The setup I tested this on I used a freshly installed VirtualBox with Ubuntu Server 22.04. I did not do any modifications to the machine and...

In the Linux world it is pretty common to use SSH keys to log into servers. They are harder to break than passwords of typical length and also save you from typing your password every time you log into your server. SSH keys can also be used with Git servers like GitHub to authenticate yourself when you are pushing to or pulling from a repository. On Windows 10 and Windows 11 it’s also possible to set up SSH and generate an SSH key without any external tools. In this tutorial I’m going to show you how to do this. Additionally,...

Ever since I started my website two years ago, this blog has been run on Wordpress. Now I have finally made the decision to ditch Wordpress and move over to Jekyll, a static site generator. I’ve spent the last few days in completely rebuilding my website from scratch using Jekyll and the Bootstrap CSS framework. What’s so special about Jekyll? In case you are unfamiliar with static site generators (SSG), they are tools that take Markdown files and HTML templates as an input and generate deployable HTML files as an output. This differs a lot from traditional content management systems...

There are situations where it is desired to have a website only available from the local network but not from the global internet. In most cases intranet websites are only served via HTTP but not via HTTPS. This however is not exactly secure, since the entire traffic between your computer and your server is transmitted in plain text (even passwords). So an attacker could obtain sensitive data as soon as they manage to break into your local network.

Everyone is familiar with the so-called real numbers, meaning numbers that we use in our daily life, like 3, -4, 0.5 or PI. As a computer science student I attend a math class at university where we not only use real numbers, but also other algebraic fields, the so-called finite fields. As opposed to the real numbers, finite fields only have a finite set of numbers. When performing the mathematical operations +, -, * or / on elements from this limited set of numbers, it is not possible to "break out" of it, i.e. the result is an element of...

As a publisher, video creator or web developer you might need screenshots of a website, that have a higher resolution than your physical monitor. For example if you have a 1920 x 1080 (full HD) monitor, but you want your screenshots to be in 4K (3840 x 2160) or even 8K (7680 x 4320). With traditional methods of taking a screenshot like Snipping Tool however, you can only take screenshots that have the same resolution as your monitor. But Google Chrome itself actually has a built-in functionality to capture higher resolution screenshots. In the following tutorial I will show you...

Projects that involve wireless data transmission are always a lot of fun – as well as projects that invole RGB LEDs. So today we will combine the two and build a wireless RGB LED controller using two Arduino Nanos and one of these cheap 433MHz RF transmitter and receiver kits. The project consists of two parts: The transmitter circuit and the receiver circuit. On the transmitter side there are 3 potentiometers that can be used to set the red, green and blue values for the RGB LED. The Arduino then constantly reads the analog values from the potentiometers and sends...

Every Android developer's career starts with the installation of Android Studio which is the software that you use to write, compile and test your apps. In this tutorial I will walk you through the installation process. Before we start it is worth mentioning, that Android Studio is quite power-hungry. The official system requirements state a minimum of 4GB of RAM, but I have used Android Studio on a machine with 6GB and it definitely wasn't a pleasure. So I recommend you to have at least 8GB of RAM. Additionally it's advantageous have an above-average CPU since you'll be running at...