Propagate deletion of C++ Objects

Last year, I spent some time rewriting internals of how groups are handled in our CAD software. Before that, groups were just to help with the selection of elements that belong together. The grouping was only one level deep, and the elements were organized flat on the document. All the calling functions had to uptate the relationships in the pointers and containers which were publicly available. This was a constant source of bugs and completely unsuitable for nested symbols that we wanted to import.

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RepRap Mendel Part1

My wive wanted to give me the first kit for a RepRap Mendel for Christmas. She was really sorry that the kit didn’t make it under the tree, as it was sold out. I was excited about the Project for more than a Year, but it was too expensive to just give it a go. Some of these projects that seem very interesting fade away with the time, or cheaper alternatives apear as it happened with the quadro copter, but the RepRap didn’t go out of my mind. So, Mirella gave me the first kit, and from here, I will build it step by step. Continue reading “RepRap Mendel Part1”

Why I gave up on voip (for now)

Voip used to be a big hype, but nowdays you don’t hear a lot about it. I thought that was because it gained wide adoption. But maybe not. At least in the company I work, we went back to a regular telephony system after having constant trouble with the voip installation.

From time to time, I hear or read about Asterisk and Freeswitch. That made me curious for some time now. Also I wanted an alternative to Skype for a variety of reasons: It’s protocol is proprietary. It’s not available on all platforms (e.g. openmoko). On Android, it drains the battery and friends tell me they get constant log-in and out notifications. And finally, the computer has to be on to receiceive calls. Continue reading “Why I gave up on voip (for now)” in Brunnen

I heard of mesh networks before,  be it from the OneLaptopPerChild or the German Freifunker community. But the recent episode of ChaosRadio about the MeshPotato got me interested enough to give it a try. The meshing community here in Switzerland is organized at Sure, I could buy a compatible router and install the provided firmware. But being a true geek I wanted to see how it works on hardware that I already have. So I started with these three devices:

I wanted to allow access to the internet, but only through an anonymizing service, so I wouldn’t get into trouble if somebody does something illegal over my wire. Continue reading “ in Brunnen”

Convert news web page into rss feed

At the company I work (BORM), we have an internal web page with the company news. We’re required to log in and check every once in a while.

Now to get notified automatically, wehen some news are to be discovered, I hacked together a PHP script that logs in, downloads and parses the news. It then serves an rss xml file to my feed reader.

In the past I didn’t do a lot of PHP scripting. Only editing some bits and pieces. So this is my biggest endeavor to PHP.

Tested with liferea and BeyondPod.

I won’t tell you where the script can be accessed, as the company news requires login. But the script itself is here:

Continue reading “Convert news web page into rss feed”

Arduino code to interface the MS5607B Intersema barometric pressure sensor through i2c

It was not quite as easy as I anticipated to interface the MS5607B sensors that I had sitting around for quite some time now. Sure, wiring them up is a lot easier. Although I still don’t like soldering SMD.

In the end, it worked out, and the code can be downloaded with the links below.



The bad thing however is that the reduction in program code that I was hoping for didn’t happen. My ChopperRemote project uses an Arduino Bluetooth which has only about 15kB of storage for the programm (sketch). That was not enough to fit in all the communications and sensor readings that I already had plus the MS5607C sensor. The Code to read the sensor used about 7kB alone. So I hoped with the i2c interface that would reduce. Now it didn’t! So I thought for holding the altitude, the Helicopter doesn’t need to know the height in cm. But could use the pressure directly and treat it as if it was linear. Lets see, how that works out…

Google Body Browser

I knew google can read my mind.

For some time now I was looking for something like GoogleEarth for human anatomy. I even thought about asking Google to make something like that.

Now I learned they did just that. They even did it as a showcase for WebGL which is part of the upcoming HTML5 standard.

Have a look at

You will need a browser with WebGL support. At the moment the beta versions of Firefox and Chrome are known to work well.

My first Android App

Yesterday, my first Android App hit the Market. Just search for flightpred and you should find it. It should run on any device running Android 1.5 and above. The App doesn’t do a lot so far. Essentially, it downloads an xml file from the flightpred server and displays the predictions for how many kilometers it thinks are possible to fly in the next three days in some flying sites on the small screen. Later I also want to add a GoogleMapsView with the circles like on the flightpred website.

I used to develop some small projects and my diploma work in Java some ten years ago. Since then the language progressed noticeably. I especially like the templatized containers. Back in the days, the containers were not type safe and I always had to cast when accessing elements. Also, the lambda’s look good.

A new flying site "Gebidum"

These days I don’t often discover new flying sites, especially not if they’re so close. Last year when searching for new sites in the Wallis I found something about Giw on the internet. That’s above Visperterminen. The chairlift was closed already, so I went somewhere else.

When thinking about where to go this weekend, that came to my mind, and I decided to go there. From the top of the chairlift one has to walk about half an hour uphill to reach the takeoff. While hiking, I saw the other mountain more north, which I thought must be the goal of the private cablecar from Eyholz. So I went to find out…

The mountain has the funny name “Gebidum” and is indeed where this obscure cablecar goes to. It’s only to service all the antennas at the top. The view was marvelous. Only the take off is not so perfect. One can take off in almost all directions, but it’s very flat, has stones, little bushes and steps. To make it perfect, while I waited and looked around at the top, the wind started to blow softly from the north. I wanted to take off south to fly along the slopes and explore the area where I walked up from the air.

Takeoff went smooth, and it was a gentle autumn flight even with some weak thermals along the way. After following the ridge to the small Giw lake, I crossed to Zeneggen before heading to Visp.

The battery of my phone was empty, so I couldn’t take no photos and no lifetracking. But the good old Garmin could still record.