Blinkenwall.com

Webinterface Screenshot

Blinkenwall..

• is the wall between our mainroom and the library
• in this wall are 9x5=45 glassbricks installed
• next to every glassbrick there is one RGB-led with a pretty neat chip attached
• these presoldered boards are called Shiftbrite
• they are currently controlled from an arduino this may change soon for something with more computational power :)
• Click here to draw something nice on the wall!!

How

SVN with current software https://whatever.metalab.at/projects/blinkenwall

We just connected the Arduino to a fonera 2202 over serial.

Now its possible to stream data for display to the blinkenwall using your favourite webbrowser.

Lessons learned:

• one can simply connect RX/TX from fonera to arduino
• no stty in default openwrt busybox build
• openwrt building is an fairly easy task
• replacing the busybox binary on a live system during operation is insane and possible! :)

Reference

• Allegro A6281 documentation
• Shiftbrite

Who

• Overflo - electronics, soldering, webinterface, fonera setup
• Wizard23 - help with electronics, basic software setup
• Metaz - arduino library software for shiftbrites
• Nex arduino software for webinterface streaming
• Mactux CSS + iphone webinterface
• Natano .C program to decode webinterface streaming files

Blinkenwall v1.5

Now with ~30 fps and network mode! Go to http://blinkenwall.in.metalab.at/ to activate network mode and send your P6 PPM frames to port 1337/tcp. Make sure that all your frames are exactly 146 bytes in size or you'll risk graphics glitches at higher frame rates.

Who

• sqrt2 - Making it work
• Amir - Netpbm library for Arduino

Lessons learned

• netcat has fixed-length 8K RX/TX buffers.
• The Arduino Duemilanove resets on DTS low (the IDE uses that to reset before programming).
• The Arduino Serial class implements an RX ringbuffer of 128 bytes. Patch the Arduino SDK to adjust this to your needs; RX_BUFFER_SIZE in hardware/arduino/cores/arduino/HardwareSerial.cpp.
• mkfifo(1) is neat when opening ttyUSB* devices leads to an Arduino reset.

Applications

• blinkblink -- old-school animations
• blinkenfft -- real-time audio FFT
• mplayer -vo blinkenwall -- watch movies in a stunning resolution of 9x5

Upgrade to Raspi

Georg and WSys replaced the Fonera/Arduino with a Raspi. Networking capability was restored later by sqrt2.

To stream to the Blinkenwall from your computer, open http://10.20.30.26/cgi-bin/togglesocket.cgi and wait for the test frame to appear, then send RGB data for the 45 pixels as before, but without the PPM header (9*5*3 = 135 bytes per frame). Open the URL again to switch back to animations.

Videos

First Blinkenwall

• http://vimeo.com/2931136
• http://vimeo.com/5714761

Blinkenwall after resurrection at Hackathon_8

• https://vimeo.com/45418812

Photos

Another Backside close-up

Backside close-up

Backside close-up with flashlight

Various Links

• Sample effect - https://whatever.metalab.at/user/meta/blinkenwall/WallSample
• SVN with current software https://whatever.metalab.at/projects/blinkenwall
• http://blinkenwall.com