In Excel, the date format depends on the locale setting of the computer, e.g., the formula =TEXT(TODAY(),”YYYY-MM-DD”) only works correctly on computers set to English locales, and =TEXT(HEUTE(),”JJJJ-MM-TT”) works on computers with German locale settings. This makes worksheets with such functions not portable between computers with different locale settings.

For some time, I have been looking for a nicely designed alarm clock and some “advanced” features, such as weekly timers and potentially DAB/Internet Radio, at a reasonable price. As it turns out, no such alarm clock exists. At least I could not find anything I like. I thus decided to build my own. I was always fasicnated by the Kindle, which is a great little device. It has a large display, consumes relatively little energy, due to the e-ink display, runs a Linux-based OS and is easy to hack. In case of the Kindle Touch, it also includes speakers. Unfortunately, it does not have a backlight, which might be quite a drawback for an alarm clock. I decided to anyway try and see how far I get with it. As it turns out, I got quite a bit further than expected in a rather short amount of time. My conclusion: Hacking the Kindle is easy, extremely much fun and the device is ideal for a large range of applications. There are a few Kindle applications out there already, e.g. Kindle Weather Display (web-based) and Kindle Weather Display (PNG-based). I used these as inspirations, but I wanted something a little more interactive, meaning a touch-controlled alarm clock. The concepts behind are descried in the following. I would still call it a prototype, as not everything es very neat, but it works, and I think it looks very nice!

When working in academia or writing your final thesis, you will come across TeX. While this is a great tool to write papers or a thesis, it has its caveats, one of these being performance. This especially holds when using TikZ or PGFPlots (which uses TikZ). When using these, every diagram and plot is redrawn every time you start your build process. To cache images, there is the function \tikzexternalize. This caches images, usually via automatically generated file names. This can lead to issues when you place a figure in the middle of your documents and do not clean the TikZ cache. Then, your figures might be confused by TeX. This is especially annoying when using the package todonotes, as every \todo is a TikZ image, resulting in confusion of ToDos whenever a new one is created. However, there is a way around this, shown here.

To connect two networks over the internet in a secure fashion, a Virtual Private Network (VPN) is often the method of choice. However, the setup of a VPN is not straight-forward, much less if one tries to connect different brands of devices together. This article describes a low-budget solution utilizing an AVM FRITZ!Box 7390 on one side and a TP-Link TL-WR1043ND v1 running OpenWrt on the other side.

As I often cite multiple sources in my articles here in Kirby, I built a minimal reference management, that lets me simply refer to these sources by a tag in the text. The actual URL of the source is then given at the bottom of the article in a separate section.

The largest Singaporean newspaper “The Straits Times” recently published an article on a row of car thefts in the neighboring city of Johor Bahru. I assisted the article’s author by supplying some technical knowledge. The article is attached below or available online.