jaseg.de

Hi there, and welcome to my personal website.

I'm jaseg, and I write about my projects here. You can find long-form articles in the blog, and links to my open-source projects on the projects page. On the top right of this page, there are links to my git repositories and social media pages. If you want to learn more about me, head over to the about page.

Recently updated projects

KiMesh

KiMesh is a KiCad plugin that automatically creates security meshes with two or traces covering an arbitrarily-shaped outline on the board.

Read more

8seg

8seg is an experimental textual display. It is made from a 45m by 1.5m large lacework banner that can be put up in a variety of spaces, conforming to the space's size and shape through bending and folding.

Read more

Blog

Getting the .ipynb Notebook File Location From a Running Jupyter Lab Notebook

2025-06-29

If you need to get the path of the ipynb file in a running #Jupyter notebook, this one-liner will do the trick. It seems chatgpt is confused, and a bunch of other approaches on the web look fragile and/or unnecessarily complex to me.

Read more

8seg Technical Overview

2023-12-26

8seg is a large-scale LED light art installation that displays text on a 1.5 meter high, 30 meter wide 8-segment display made from cheap LED tape.

Read more

Ubiquiti EdgeRouter on Deutsche Telekom GPON Fiber

2022-02-21

Short tutorial on getting a Deutsche Telekom GPON internet connection running using a SFP ONU unit in an Ubiquiti EdgeRouter.

Read more

New Paper on Inertial Hardware Security Modules

2021-11-23

Paper announcement: We have published a paper on how you can DIY a tamper-sensing hardware security module from any single-board computer using a moving tamper-sensing mesh made from cheap PCBs.

Read more

Kicad Mesh Plugin

2020-08-18

I wrote a little KiCad plugin that you can use to create security meshes, heaters and other things where you need one or more traces cover the entire surface of a PCB. The plugin supports arbitrary PCB shapes, cutouts, and can route around existing footprints and traces on the PCB.

Read more

Private Contact Discovery

2019-06-22

I gave a short introduction into Private Contact Discovery protocols at our university workgroup.

Read more

Hardware Security Module Basics

2019-05-17

I gave a short introduction into Hardware Security Modules at our university workgroup, including an overview on interesting research directions.

Read more

How to talk to your microcontroller over serial

2018-05-19

Scroll to the end for the TL;DR.

In this article I will give an overview on the protocols spoken on serial ports, highlighting common pitfalls. I will summarize some points on how to design a serial protocol that is simple to implement and works reliably even under error conditions.

If you have done low-level microcontroller firmware you will regularly have had to stuff some data up a serial port to another microcontroller or to a computer. In the age of USB, an old-school serial port is still the simplest and quickest way to get communication to a control computer up and running. Integrating a ten thousand-line USB stack into your firmware and writing the necessary low-level drivers on the host side might take days. Poking a few registers to set up your UART to talk to an external hardware USB to serial converter is a matter of minutes.

Read more

Thor's Hammer

2018-05-03

In case you were having an inferiority complex because your friends' IBM Model M keyboards are so much louder than the shitty rubber dome freebie you got with your pc... Here's the solution: Thor's Hammer, a simple typing cadence enhancer for PS/2 keyboards.

A demonstration of the completed project. h264 download / webm download

The connects to the keyboard's PS/2 clock line and briefly actuates a large solenoid on each key press. An interesting fact about PS/2 is that the clock line is only active as long as either the host computer or the input device actually want to send data. In case of a keyboard that's the case when a key is pressed or when the host changes the keyboard's LED state, otherwise the clock line is silent. We ignore the LED activity for now as it's generally coupled to key presses. By just triggering an NE555 configured as astable flipflop we can stretch each train of clock pulses to a pulse a few tens of milliseconds long that is enough to actuate the solenoid.

Read more

32-Channel LED tape driver

2018-05-02

Together, a friend and I outfitted the small staircase at Berlin's Chaos Computer Club with nice, shiny RGB-WW LED tape for ambient lighting. For this installation, I made a 32-channel LED driver that achieves high dynamic range on all 32 channels using a cheap microcontroller by using Binary Code Modulation.

Read more