Installing Chromium on Raspberry Pi without desktop

Start with a Rasbian light version.
Install chromium and x-server
sudo apt-get install chromium-browser
sudo apt-get install –no-install-recommends xserver-xorg

If you now start chromium-browser it will show the following error:
Failed to put Xlib into threaded mode.

Gtk-WARNING cannot open display

this is because you have to start it with xinit:

xinit chromium-browser

Chromium will start, but you will need a minimal window manager.

sudo apt-get install matchbox-window-manager

Now you need a shell script to start your chromium

sudo nano

Insert the following lines, Exit with ctrl+x, Y and Enter.

matchbox-window-Manager -use_cursor no&

chmod +x

Start it now with:

xinit ./

Add Chromium options as you like. E.g. –Kiosk –allow-running-insecure-content plus your URL


Infotainment Gesture-Control

Lately we worked at EDAG on testing gesture control. We, that’s Adrian my trainee and me. Yeah and the hand you can see there is mine. 😉


Silent Meditation Timer for a Singing Bowl

In 2014 I had another idea about a meditation timer for singing bowl (Klangschale). A clapper which automatically hammers after a specified amount of time.

I had some features in mind:

  • It needs to fit on a wide range of bowls.
  • The mechanics needs to be silent.
  • The timer needs to be adjustable
  • Maybe it can also bell in adjustable time intervals, like Tich Nhat Hanh’s mindfullness bell

Motors, servos and solenoids are all too noisy. So I made some research and found electric muscles. I ordered two from sparkfun. And I made some scribbles how it can look like.

I think it would be nice that the time can set by a rotary encoder, combined with a little display, maybe 7-segment led or a small oled, like in the MicroView

The latest thing I made is a paper prototype with a simple button. I was amazed, the mechanics works perfect. And it’s really silent.


The click in the video is just the button press. The NanoMuscle itself is very silent.


New Enclosure for my Knob

In 2013 I started designing a nice enclosure for my knob. But unfortunately I never finished it. I designed it by layering laser cutted acrylic glas.

It has the followong features:

  • Li-Po battery power
  • Wireless charger
  • Stand for iPad and iPad mini
  • Bluetooth Audio connection

Here are the vector files which i have used for cutting.


mysqldump windows command line only databases with prefix

Here’s a little snippet which mysqldumps only the databases with a specific prefix or another wildcard expression under windows command line or windows batch.

@echo off
setlocal enabledelayedexpansion
set myvar=
for /f %%i in ('c:xamppmysqlbinmysql -uroot -pmysql -e "SHOW DATABASES LIKE 'prefix_%%'"') do set myvar=!myvar! %%i
echo %myvar:~10%
@echo on
c:xamppmysqlbinmysqldump.exe -u root --password=mysql --databases %myvar:~10% | "c:Program Files (x86)gzipgzip.exe" > "C:WHEREEVERYOUWANTmysqlbackup-%date:~6,4%-%date:~3,2%-%date:~0,2%-%time:~0,2%-%time:~3,2%-%time:~6,2%.gz"

THE KNOB III – BlueTooth 4.0 aka BLE

Here is a new Version of my rotating Knob. It now uses Bluetooth Low Energy aka BT 4.0 to communicate to the iOS device. I’m using the BLE Shield by RedBear Labs. I also coded a native App to have access to the iOS music library. So now it kan be used as a replacement for that cool, but expensive, infotainment systems integrated in cars. Mine doesn’t have one. On the other side Toyota’s infotainment systems aren’t cool. Hey guys take a look at Audi or BMW. And last but not least it has a new case with an aluminium knob. It looks very nice now. In addition it is enough space to put in a 9V battery to use it completely wireless.


THE KNOB II – Wifi-Hardware

You know, I’m addicted to rotating knobs. And this is my new version. This one works over Wifi. So it works for desktop and mobile, native and Adobe Air. It is build with an Arduino Leonardo, a RedFly Wifi Shield and a ProtoShield with 10 buttons, 1 rotary encoder and 3 LEDs.

On the software side I’m using the OSC protocol over UDP which is very fast and responsive.