This is freeware. The advantage is that it is free, the disadvantage is that I take no warranty for eventual bugs. If you find any, please contact me and sometimes I can fix them.

VC840.jpg (8736 bytes)

  Datalogger for VC840 multimeter


for VC840 and UT60E

allows display and logging of multimeter values, can copy them to the clipboard and thus offers the possibility to paste them into EXCEL or whatever.
(J.C. Feltes, based on readout code by H.J. Berndt)


mtdraw.jpg (14664 bytes)

MTDRAW is a simple drawing program especially useful for drawing electrical circuits.
It has the possibility to put reusable macros into a library
Easy drawing of coordinate systems, sine waves and any curves.
The drawings can be imported via clipboard to any WINDOWS application.
(J-M. Frantz and J.C. Feltes)


Some drawing libraries

timer_calculator.jpg (14664 bytes)

AVR timer calculator

AVR timer calculator calculates the Compare register values necessary to achieve a certain timer interrupt time.
Needs a Python 2.x installation with Tkinter (for the GUI)

I programmed this little application because I find it useful, and as an exercise in Python GUI programming. ( J.C. Feltes)

Kurzanleitungen Open Source Software und Linux / Summaries for Open source software and Linux

Da ich mit zunehmendem Alter immer vergesslicher werde, schreibe ich mir das Wichtigste auf. Hier gibt es Kurzanleitungen anhand von Beispielen.
My memory is not very good. In this place I store short summaries that are useful to me (and maybe to someone else)


  • Summary of important bash commands (english)

    Diagramme / Diagrams

  • Gnuplot Survival Guide

    Mathematik / Mathematics

  • WxMaxima

    Python Doc

  • Basic Python programming by examples
  • All I ever wanted to know about modules ... and tried to find out ...
  • Matplotlib Grundlagen
  • How do I find the path to a Python script
  • How do I fit a curve to measured values?
  • The Jupyter notebook for interactive scientific programming

    Python Library

  • A textbox directly connected to a serial port, for Tkinter
  • Nonblocking reaction to key press, for console programs

    Linux and AVR microcontrollers

  • Geany als IDE für die BASCOM-Programmierung


  • FreeCAD web links
  • My (very uncomplete) summary of FreeCAd scripting in Python
  • From draft to G code A short summary for the Path Module of FreeCAD 0.17
  • Topological scripting The principles
  • Creating objects with SolidPython in FreeCAD. How to start SolidPython allows us to do OpenSCAD things, with a friendlier Python syntax,


  • From drawing to CNC: an overview
  • CAM: Generating toolpaths with HeeksCNC
  • LinuxCNC Konfiguration für High-Z S-400
  • LinuxCNC: Generating a signal on the parallel port with HAL
  • Heeksfunctions: generate 2D objects, pocket, profile and drilling operations for HeeksCAD The Pythonic approach to 2.5D CNC milling. All objects are generated by code (as in OpenSCAD). This allows the use of variables, for loops and calculations in the drawing script. The only thing to do in HeeksCAD is "Menu - Post process" to get the G code for the machine. Collaboration welcome!