Welcome

This is my home in the virtual world, where I write about things that I want to share. The freely available software that I've written as well as some of the photographs I've taken over the years can also be found here. Please use the navigation links on the right if you are looking for something.

Recent articles

1. Measuring particulate matter with the PMS5003

   This article details how I used the Plantower PMS5003 particulate matter (“PM”) sensor on a PC or laptop, using an FT232H breakout board to make the connection.

2. Storing and graphing time-based data

   In this article we will look into the best way to store time-based data and use it with gnuplot.

3. Yes, please: #DeleteFacebook. But don’t leave it at that.

   Cut facebook out of your life altogether.

4. Video manipulation with ffmpeg

   Serveral useful recipes for manipulation video with ffmpeg.

5. Adding an overlay to each page of a pdf file

   We can use PostScript’s Endpage procedure to e.g. add a signature to each page of a PDF file, using only ghostscript.

6. Install ntpsec on FreeBSD

   A short article on how to install ntpsec on FreeBSD. Tested with 0.9.7 and 1.0.0.

7. Transplanting noscript settings and bookmarks to another machine

   After upgrading a laptop to 12-CURRENT, I had problems with firefox 57 choking on some javascript in an extension. So I renamed my ~/.mozilla directory and let firefox create a new one. That solved the problem. But with that I lost my noscript settings and my bookmarks.

8. Using sqlite3 for time management

   After some initial experiments with sqlite as a replacement for a json data file format (which I did not pursue in the end), I have now started using sqlite in earnest. And I must say that I quite like it.

9. Database scheme for resin recipes

   This document explores how an SQLite database could be used to store data for the resin-calculator. Normally, the recipes are a dictionary keyed to the name of the resin. The value of each recipe is a list of (component, parts-by-weight) tuples. Since a database only contains tables, where each row has the same form, how do we store such infomation in a database?

10. Convert RCS history to git

    Before the rise of git, I used rcs as my version control system. Because I want to standardize on git, I am slowly converting old repositories.

    In this article I’ll be converting my old perl scripts in ~/src/perl.