Fixing Full-HD VGA support for the Epson EH-TW5200 Projector

If you happen to own an Epson EH-TW5200 projector, you might have experienced problems setting Full-HD (1920×1080) resolution using a VGA connection under linux. When I set the resolution to Full-HD, the whole screen would stay completely black. This is just a quick fix for the other 4 people that might have this problem.

The difference between the original modeline and the new one is the vertical refresh rate: The projector proposed 60.02 Hz via EDID, and the new modeline is just a tad slower, using 59.94 Hz. I was connecting a ThinkPad T60 to the projector, so the problem might also be the RAMDAC of the laptop, something about blank phases, who knows.

 

Homeserver Upgrade: Odroid XU3-Lite Setup on a SD-Card

I recently bought a new home server, the Odroid XU3-Lite to replace my poor man’s home server I called the thin-server, to run CherryMusic and the like.

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That little ARM machine is a beast in the size of a cigarette pack, featuring a total of eight CPU cores, an ethernet port and most importantly an USB 3.0 port to connect an external hard drive. It also comes with a plastic case, with a small fan inside and a PSU that is strong enough to power external hard drives connected to the USB ports. I ordered the smaller “Lite” version, which has a slightly lower CPU clock rate, but costs a lot less than its bigger brother.

In this post I’ll guide you quickly through the installation process of the ubuntu image on a micro SD-Card, how to make use of all the space on the microSD card and how to secure this little fellow a little after the installation of the image.

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QCAD – Symbols, special characters and font styles in dimension labels

Cover - QCAD with Alpha and l_ABz dimensions

QCAD is a great free and open source CAD software. Although limited to 2D design, it is my favorite tool for drafting, construction and simple sketches. It is well documented overall, but one issue I could not find a solution for, was how to label dimensions with symbols, special characters or certain font styles (bold, italic, super-/subscript).

This blog post provides a simple trick to get it done.

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Maxima (software) and gnuplot – plot functions using lines with symbols on it (workaround)

maxima-title-workaround

I am recently working on some scientific papers for which I have to visualize a lot of mathematical functions. In a good scientific paper the graphs (and visualizations in general) should be colorless and utilize dotted/dashed lines or lines with symbols on it instead of colors. This has several advantages: A colorless plot is more neutral to the reader, he/she does not get distracted by the different colors. A reader may also have a (subliminal) preference in color, so he/she pays more attention to e.g. the red curve than the yellow one, that is hardly readable on the white background anyway. This also helps to distinguish functions, if they are plotted in one diagram and printed in gray scale mode or read by color blind people. Also, if two identical functions are plotted in one diagram, using just colors will probably only show one of the functions and hide the other.

I am using the CAS software Maxima to do the calculations, which in turn uses gnuplot to plot the functions. Gnuplot alone does the job perfectly. However, when plotting functions (and not discrete data points) using lines with symbols on it from within Maxima (which also uses gnuplot to plot the graphs), the results are quite ugly. There seems to be no proper solution to this problem.

This blog post suggests a workaround that is rather ugly, but which produces very nice graphics, that meet the above-mentioned requirements.

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Samsung SSD 840 EVO 2.5 Zoll SATA – Firmware update under GNU/Linux

I recently bought a Samsung SSD to replace my HDD in my Arch Linux notebook. It is a “Samsung SSD 840 EVO 2.5 Zoll SATA”. One of the first things I do when I get new hardware is to make sure the latest firmware is installed. Mine did not have the latest firmware update and – as it was to expect – Samsung SSD firmware updates under GNU/Linux are not (officially) supported. Samsung ships only Microsoft Windows software, called “Magician”, which can directly update the firmware or create a live USB-Stick to do the update. Additionally, they provide *.iso image files (one for Microsoft Windows systems and one for Apple computer, respectively) to update the firmware from a live CD. The *.iso image file intended for Microsoft Windows would also work under GNU/Linux, only that my notebook does not have a CD Drive anymore. Obvioulsy, the only option left was to create my own live USB-Stick under GNU/Linux – without using Microsoft Windows and that crappy Samsung “Magician” software. A simple “dd” comand to “burn” the *.iso file on an USB-Stick did not do the trick, as the Isolinux version Samsung uses is over 10 years (!) old.

This article shows how to update the firmware of a “Samsung SSD 840 EVO 2.5 Zoll SATA” under GNU/Linux using a bootable live USB-Stick.

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The “Matrix Code” in your linux terminal using python and curses

Everybody knows the code on the screens in the movie the matrix. You can see it for example when the character “cypher” talks to “neo” somewhen in the night, and the green letters fall down on those second-hand dell screens behind them. Funky. I want that too.

cypher_neo_code

I’ve written a python program that uses curses to create a similar looking animation and just now cleaned up the code a bit and made sure it runs in python 2 and 3. You can get the source code on github and there’s a screenshot and a short explaination after the break…

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Poor man’s DynDNS – A PHP solution

I’m running a Thin-Client as a home server and sometimes I need access to some files at home. Since those no-ip services didn’t prove that reliable in the past, I decided to implement a DynDNS substitute in PHP.

The concept is quite simple: Let the little server at home call a PHP script somewhere on a “big” Server that has a static IP. The big server then writes the IP to a file, so it can be read from anywhere. There are two scripts that have to reside on the big server: an index.php, which reads and echoes the IP, that was recorded, and another script in a .htaccess protected folder, which is able to write the IP of the home server to a file.

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RAID5-Server to hold all your data – the NAS alternative with software RAID

This was an old project of mine. A few years ago I had a huge load of data comming in (~4 TiB) and the amount of storage I needed suddenly more than dubbled. Until then I was using two 1.5 TB HDDs which I mirrored by hand using rsync, because I’m paranoid of loosing data. It was annoying to always copy all data to each disk to have redundancy – and certainly not a smart solution. Now that data wouldn’t fit onto the two disks anyway, so it was time to think of a new solution. I had enough of wasting my time with copying files from one hard drive to another.

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