Raspberry Pi – Ultrasonic Distance Sensor part II

Using python for the ultrasonic distance sensor from part one of this post in a project I realized: It is still too slow. In my project I record high queality video using the raspberry pi camera at high resolution. That puts quite some load on the IO. As a result, the timing needed for the […]

Raspberry Pi – Ultrasonic distance sensor

For a current hobby project I need an ultrasonic distance sensor. They work by sending a short pulse of ultrasound and measuring the time $t$ it needs to get reflected back from the first obstacle. A nice introduction can be found here. The distance traveled by the sound $d$ can then be calculated from a […]

Revisions of Latex documents

Like lots of other people I have come to like latexdiff to highlight changes between versions of latex documents. It takes two latex files as input and outputs a new latex file, in which changes are highlighted. I use a lot of pgf/tikz for graphics and latexdiff will destroy tikzpicture code. To avoid that I […]

Pyorbit and numpy

On Wednesday I started looking into py-orbit (the orbit tracking code for python). In order to quickly see what happens with the particles I wanted to be able to directly access the particle coordinates as a numpy array. The builtin c functions will only give you a pointer to the particle array and the builtin […]

PDF-OCR: Sorting documents into searchable PDFs

I’v gotten rid of paper at home by installing an automatic scanner/OCR/document sorting system on based on an all-in-one printer-scanner and a raspberry pi. For years I’ve been struggling to keep up with bureaucracy. I do really dislike everything to do with official papers. In most years that meant that I would just briefly read […]

Fixing missing ia32-libs on Ubuntu 13.10

Some commercial packages (namely AftershotPro) still depend on the old 32 bits compatibility libs for ubuntu. The package is obsolete for a long time now as the new ubuntu distributions are compatible with 32-bits stuff from the start (at least that’s what I gather from various sources). For aftershot there were two approaches: Install the […]

Coding: python particle to grid interpolation

[latexpage] In particle tracking simulations you often need to interpolate particles onto a grid in one or more dimensions. Recently I decided to write a linear particle-to-grid interpolation in one dimension in python.This is an educational introduction into interpolating particles onto a one-dimensional grid. Interpolation of particles onto a grid Particles are usually described by […]

Backup strategy on untrusted FTP

Update: Before implementing this method you might want to look at duply which uses gpg to implement the same functionality but does not need large image files. We own a server which is used to keep e-mail and other personal data off the commercial cloud. Partly because of paranoia, partly because of the enjoyment of […]

Raspberry Pi – Animated temperature plot

For the Christmas party yesterday I was asked to bring a large pot. The contents were supposed to be, as is customary in Germany mulled wine (Glühwein). Mulled apple wine in this case. Besides a pot we needed a hotplate which was brought by a colleague. Well, having mulled wine on a hot plate has […]

Tune diagram in python

I am trying to move whatever I can to python. The main reason being that I want it to be free, and not require expensive commercial software. So recently I took the time to revisit my Mathematica code for the tune diagram and port it to Python. Basically I rewrote the whole thing and it […]