Random wallpaper from pictures and subfolders
The OS X desktop changer does not follow subfolders in the image source folder. Since SnowLeopard the Screensaver will use the images in subfolders but the Desktop changer will not. As a workaround you can create a folder with links to all images, including images in subfolders (recursively).
In System preferences set the Desktop changer to point to the folder with the links as image source.
Here is a shell script that will create symbolic links (in ~/Desktop/Wallpapers) to all pictures (in ~/Pictures) recursively: wallpaper_links.command
This Python script will show the path to the current image: tkWallpaperCurrent.py
Protected: Gesproken brief
SphereBot Arduino shield
An Arduino (Uno) shield for two stepper-motors, one Servo motor, and an alternative output. For the SphereBot, another Egg-Bot derivative.
This SphereBot is built with a retired Sparkfun Arduino Ethernet Pro board and the steppermotors from a 2009 Makerbot. Firmware and host sw (fork) from thunderbug1.
Download the Eagle schematics and board (100 KB).
A simple Time Domain Reflectometer
I built the simple signal generator described in Electronic Design. The same circuit you find on ZL1NC and epanorama. Together with an Oscilloscope it can be used to find a cable fault as described in this All about Circuits article.
The 74AC14 SMD is mounted on the board its trace side. All other parts are through-hole. Most parts were salvaged from old electronics. You can adapt the PCB to your needs.
Raspberry Pi Hometheater
I was a happy user of the first model Apple TV. Then the iTunes ecosystem grew bigger and bigger. On top of that the new Apple TV is cloud- or network-based only. Not all my music can be found in the cloud, and I prefer it nearby, i.e. without the need of access to some NAS or other PC in the network. So I switched to a Raspberry Pi model 2B and 500GB harddisk in combination with Kodi.
Recently I upgraded this box with the model 3 Pi. Here follows the configuration.
Ciclop scanner shield
BQ’s Ciclop scanner comes with its own ZUM boards. My home made version is built with parts lying around, such as an Arduino Uno. Hence this simple shield for the Uno.
Download the Eagle schematics and board (100 KB).
Oorlog en Vrede
Oorlog en Vrede (Vojna i Mir) L.N. Tolstoj (1828-1910)
Met zoveel romanfiguren is een schema van de belangrijkste personen wel zo handig bij het lezen.
Oorlog en Vrede
Lev Tolstoj
Vertaling Peter Zeeman en Dieuwke Papma
Tweede druk 2005
Veen Bosch & Keuning uitgevers n.v., Wommelgem, België
ISBN 978 90 4141 4595
Download het schema met romanfiguren (PDF 50 KB).
OwnCloud Dropbox alternative on a Raspberry Pi

Create your own Dropbox-like solution with a Raspberry Pi and the OwnCloud open source solution.
OwnCloud creates a folder on your computer the content of which will be automatically kept in sync with both the host and all of your peers when files are added, removed or edited.
Continue reading “OwnCloud Dropbox alternative on a Raspberry Pi”