Der Name Greta Thunberg ist derzeit in aller Munde und das ist gut so. Warum sie Recht hat mit ihren Positionen, ihren Forderungen und ihrem Handeln zeigt dieser Artikel. Continue reading
This post collects some information and my own experience about setting up a headless raspberry pi – this means there is no keyboard, monitor or mouse connected to the raspi. All the communication to the user is done via ethernet. In my case there’s also no graphical interface. There is nothing new in this article. It is a compilation of information found at different places over the internet. But as it took me some time to find it I thought it could be helpful to have it all in one place. Continue reading
A hot wire cutter as the one I described here only cuts in a straight line. Now I wanted to integrate some installation tube in my styrofoam. So I had to cut grooves into the foam. Cutting them with a knife won’t give a good result and so I had to find a new way to get the right shape. The idea was to bring a piece of wire in the shape I wanted to cut out of the foam and then to slide it through the foam.
Everybody knows – and many of us celebrate – the four Sundays of Advent every year. The First Sunday of Advent is often recognized as the beginning of christmas season. And celebrating the Sundays of Advent often goes together with an advent wreath with the four candles on it. So far – so good.
But: What most people don’t know is the fact that there is another Sunday of Advent which is called the 0th Sunday of Advent. This is very unknown but also very logical. One week before the 2nd Sunday of Advent is the 1st Sunday of Advent. So here it is: The 0th Sunday of Advent is one week before the 1st Sunday of Advent! Surprisingly this is also completely unknown to e. g. computer scientists or nerds who know that their computers start counting by zero. Continue reading
My experience with the solar eclipse on March 20, 2015 began one day before: A primary school teacher told me that the parents had to sign a form freeing the scool from any responsibility if their children get hurt from watching the eclipse. Furthermore, the parents were made responsible to equip their children with appropriate eclipse glasses. Children who didn’t bring the signed forme were refused to watch the eclipse. So what i’m asking myself is: What do these children learn? Do they learn something about nature and how to deal with extraordinary events or do they grow up in a climate of fear and learn how to delegate any responsibility to somebody else? Btw. the german word Angst also exists in english… Continue reading
A hot wire foam cutter is a very useful tool to cut any type of styrofoam boards (expanded or extruded polystyrene) into the shape you want. The goal of this project is to build a low-cost cutter mostly from parts I found in my workshop that is able to do precise and straight cuts. Vertical and also miter cuts should be possible. This is a real hardware-only-project: no arduino, no programming, just plain mechanics and electrics: A thin wire is held in place and heated by a current. Continue reading
To keep the posts readable and loading time comfy I divide the series into parts. This is part two of the pictures from the chestnut tree right before my window. Have a look at what is happening from day to day and enjoy what nature is doing! This project is a work-in-progress and new pictures are added on a daily basis. Note that the pictures are not processed with filters, colour changes, sharpening or anything else. I only scale them down to fit into this post.
Right before my window lives a big chestnut tree. As it is springtime now the buds are bursting and everything is growing. I decided to take a picture of one of the buds every morning. These pictures show the fascinating process of the buds when they get open and leaves and flowers appear. This post is a work in process starting with the first picture on March, 30 (ok, there is no picture fom March, 31). All these pictures aren’t photoshopped in any way. I only shrink them in size.
heliosoph Continue reading
In my lab I have some test and measuring equipment like an arbitrary function generator, a desktop multimeter and a DC power source. All of these devices have a GPIB (IEEE.488) interface. So what I want to do is to control these devices from my Debian Linux computer and to read out data. Continue reading
As laser cutters don’t bring any mechanical force to the object that has to be cut or engraved they often don’t have any fixing for the material. It simply lies freely in the machine.
When you want to cut some plywood with a laser cutter the problem that occurs most of the time is that the plywood doesn’t stay in a flat state. It either can be already waved when you buy it or store it at your site and the laser can do the same while cutting because of the laser’s heat. You can see this also when cutting acrylic heavily. This effect will always make you a problem because the laser needs a flat object to work on. Otherwise there is no proper focussing in every region of the cutting area. For good results your plywood has to be flat before and during the cutting process. So you have to make it flat by fixing it on the machine. Continue reading