Category: Projects

[Art] Suomalainen Äänimaisema

Suomalainen Äänimaisema was an project of Melanie Windl, an artist from the University of Mainz, Germany on which I helped as technical advisor and programmer. The idea of the project was to field-record several sounds and music of Finland, load them onto some Raspberry Pis and let them play, as soon as a person came close enough to the object. The project was realised using three Raspberry Pi, Modell B+, some PIR sensors and USB Soundcards. You can find more about the project here: https://atelier-windl.com/portfolio/suomalainen-aanimaisema-2/

Exhibition
Suomalainen Äänimaisema
25.03.-02.04.2015
Titanik Galleria, Itäinen Rantakatu 8
20700 Turku, Finnland

Suoma_01

A short video showing the project can be found here

[RaspPi] HDMIPi Repair and VGA Upgrade

Sadly, some weeks ago, the Micro USB Port of my HDMIPi broke.
I wrote an letter to Alex Eames, which is quite known for HDMIPi, RasPi.TV and his lattest Kickstarter Project the RasPiO Duino.
Alex is an awesome guy and gave me his blessings to try to repair that problem myself.
With some flux, a fine solder tip and soem patience, you can get that repaired in no time.
After succeeding, I created some strain-relief by using two-component epoxy resin to glue it down a bit. Highly recommended!

As I already saw the unused VGA pinout on the HDMIPi and had the screen taken apart, I decided to hack an old VGA Connector from an even older VGA ATI/S3 Trio/Dunno-something-very-old Graphics Card :). I just soldered it in - in it worked right away! However, due to the fact of the included 12mm M3 Spacers and the additional height of the board due to the VGA Connector, I could not attach the back plate of the HDMIPi. I don't recall the exact size, but I think I came up with 18mm M3 Spacers which I only used to replace the original 3 Spacers on the bottom part of the HDMIPi. That way, the buttons of the Display would still be seated nicely and I could access the GPIO Ports of the RPi quite well.

Some photos:

hdmipi_1

hdmipi_2

hdmipi_3

hdmipi_4

hdmipi_5

[RaspiPi] RF24 Radio Link between 2 Raspberry Pis

Hi there,

awesome coder TMRh20 did write some cool librarys for the widely used RF24 radio modules.
These tiny things work with SPI and thanks to TMRh20s work, you can use them quite easily to connect two RPis.
You can find his/her Github on https://github.com/TMRh20, as well as a lot of good documentation on his/her blog http://tmrh20.blogspot.de/ and github.io http://tmrh20.github.io/

To make it short and connect to RPis, this is my reciepe, worked out with TMRh20 - Thanks a lot!

1.) You should connect the RF24 modules to your two RPis like shown here:
https://github.com/TMRh20/RF24Network/tree/Development#connection-info
I did not change anything in the config but did just connect the modules like mentioned in the table:

Pins:

PIN -- NRF24L01 -RPI --------- RPi -P1 Connector
1 ---- GND ----- rpi-gnd ----- (25)
2 ---- VCC ----- rpi-3v3 ----- (17)
3 ---- CE ------ rpi-gpio22 -- (15)
4 ---- CSN ----- rpi-gpio8 --- (24)
5 ---- SCK ----- rpi-sckl ---- (23)
6 ---- MOSI ---- rpi-mosi ---- (19)
7 ---- MISO ---- rpi-miso ---- (21)
8 ---- IRQ ---- - ------------- -

2.) Install dependencies:
sudo apt-get install libboost1.50-all

3.) Install RF24toTUN on all RPis
mkdir rf24
cd rf24
wget http://tmrh20.github.io/RF24Installer/RPi/install.sh
chmod +x install.sh
sudo ./install.sh

Do you want to install the RF24 core library, Y/N?Y
Do you want to install the RF24Network library?Y
Do you want to install the RF24Mesh library?Y
Do you want to install the RF24toTUN library?Y
Do you want to compile RF24toTUN with RF24Mesh support?N

cd rf24libs/RF24Network/

vi RF24Network_config.h
change #define MAX_PAYLOAD_SIZE
to #define MAX_PAYLOAD_SIZE 1514

sudo make install -B

cd ..
cd RF24toTUN/

vi rf24totun.cpp
goto line 209: while(!radioTxQueue.empty() ) { // && !radio.available() ) {
and change it to: while(!radioTxQueue.empty() && !radio.available() ) {

sudo make install -B

4.) Use the Tunnel on both RPis (you're in the RF24toTUN folder :)!):
Node 1, Master:
sudo rf24totun_configAndPing.sh 1 2
answer 0 for Master
got now IP: 192.168.1.1

Node 2, Client:
rf24totun_configAndPing.sh 2 1
answer 1 for Client
got now IP: 192.168.1.2

After that you can ping each other, even with -s100 for 108 bytes payload, or use ssh and such.

Addition:
If you want to use the LAN/WAN Connection of the Master RPi from your Client, you need to do following:
a) Master Site:
sudo sysctl -w net.ipv4.ip_forward=1
sudo iptables -t nat -A POSTROUTING -j MASQUERADE
# To forward and allow traffic, as mentioned here: http://tmrh20.github.io/RF24Ethernet/

b) Client Site:
sudo route add default gw 192.168.1.1 tun_nrf24
# Configure default gateway to the IP of your Master RPi and use the RF24 device to connect to it

[RaspPi] Raspberry Pi and the ili9341 Display

https://www.youtube.com/watch?v=cEcIem6R4aQ

1.) Enable SPI
# remove or comment out the spi blacklist line
sudo nano /etc/modprobe.d/raspi-blacklist.conf

2.) Install
a) FBTFT drivers as loadable modules
sudo REPO_URI=https://github.com/notro/rpi-firmware rpi-update
sudo shutdown -r now

OR

b) FBTFT drivers built into the kernel proper
sudo REPO_URI=https://github.com/notro/rpi-firmware BRANCH=builtin rpi-update
sudo shutdown -r now

3.) Install the frame buffer driver (as root):
apt-get install xserver-xorg-video-fbdev

4.) Configure frame buffer driver:
sudo vi /usr/share/X11/xorg.conf.d/99-fbdev.conf
Section "Device"
Identifier "myfb"
Driver "fbdev"
Option "fbdev" "/dev/fb1"
EndSection

5.) add Autostart:
( the gpios= Pins need to be changed to YOUR specification and connection! )
sudo vi /etc/modules
fbtft_device custom name=tm022hdh26 gpios=reset:25,led:23,dc:24 rotate=90 bgr=1
#on my selfbuild shield
#from usb -> sd card laengs
#fbtft_device custom name=tm022hdh26 gpios=reset:25,led:23,dc:24 rotate=180 bgr=1
#from cinch -> hdmi quer
#fbtft_device custom name=tm022hdh26 gpios=reset:25,led:23,dc:24 rotate=270 bgr=1

6.) add Auto login:
sudo vi /etc/inittab
#1:2345:respawn:/sbin/getty --noclear 38400 tty1
1:2345:respawn:/bin/login -f pi tty1 /dev/tty1 2>&1

7.) add Autostart X:
sudo vi /etc/rc.local
su -l pi -c "env FRAMEBUFFER=/dev/fb1 startx &"

8.) Console at boot
Add kernel argument to file /boot/cmdline.txt
fbcon=map:10

Infos taken from:
https://github.com/notro/fbtft/wiki#install
http://marcosgildavid.blogspot.de/2014/02/getting-ili9341-spi-screen-working-on.html

Video was played with this worm-of-a-command-string:
sudo mplayer -nolirc -vo fbdev2:/dev/fb1 -fs -x 320 -y 240 -zoom -framedrop -lavdopts lowres=1:fast:skiploopfilter=all ~/BadApple.avi

elektor Live 2013

You can find my slides from the elektor Live 2013, Raspberry Pi 101 Workshop here: elektor_RPi_2013_Maas.pdf [ 6,1 MB ]

The handout or "cheat-sheet" can be downloaded here: elektor_RPi_2013_Maas_Cheat_Sheet.pdf [ 0,4 MB ]

... and finally, you find the Sourcecode of the Sample Projects here: elektor_RPi_2013_Maas_Sourcecode.zip [ 0,03 MB ]

Videorecording of the talk can be found here