Projects on the orange bench

by Dirk Grappendorf

Welcome to

This is a private Website where you can learn about my past and ongoing projects (mainly electronics and computer stuff) and other things that interest me. Look around and feel free to leave me a comment.

Fetaured Projects

  • Signal Tower

    Signal Tower
    Yet another continuous integration status indicator for agile software development teams
  • 6502 Homecomputer

    6502 Homecomputer
    This is a project that I've often started, but haven't completed until now because i knew that it would take quite a long time: building my own 8-bit home computer from scratch. The idea was to design a computer like the C64, almost only using parts that were available when this computer was manufactured.
  • Caretaker - Smart Home Automation

    Caretaker - Smart Home Automation
    Caretaker is my DIY smart home automation and survaillance project. The aim is to create a totally wireless and scaleable system to control power switches (lamps and other electrical appliances) and measure values like temperatures, brightness and power consumption.
  • Analog Computer Construction Kit

    Analog Computer Construction Kit
    Inspired by Dr. Vogels Home Brew Analog Computer , this kit consists of various 100x60 cm PCB cards which can be connected together with 2.54 mm jumpers. Connect the various input and outputs of generators, adders, integrators and multipliers to compute different mathematical functions.


2016 Jul


Recently I bought a small and inexpensive 2-port KVM (DVI/USB) switch that I installed with the intention to switch between my Linux and Windows workstations. Marketing promises that I could switch by pressing Scroll-Lock or Ctrl on my keyboard two times. The sad reality is: this only works if the currently active workstation is the Windows one (WTF!?).

This article briefly describes how you can add an ESP8266 module to a KVM switch, which allows toggling between the two computers by sending...


2016 Mar


Signal towers, or stack lights, are usually used in industrial manufacturing and display the state of a machine to the operators. When a malfunction occurs, the operator can immediately recognize this and react accordingly.

Software development teams can also use these signal towers to display the success or failure of the last builds of their code base. A simple red/green indicator gives the developers immediate feedback if the current code contains some errors which they may have introduced...


2016 Mar


Once in a while you need to update the design of your website. This new design is based on the Volcano Foundation Template from pixelhint.

After using the content management system Refinery for the last couple of years, I now switched to the static website generator Middleman.

For me as a software developer it is much easier to write my page content inside IntelliJ and it is also much simpler to modify and extend a static website generator instead of a full featured CMS.


About me

I'm a senior Software Architect, Scrum Master, Team Lead and Software Developer currently located in Dortmund, Germany.
I'm always interested in new innovative and challenging tasks, so feel free to browse through my resume and leave me a note.