Sources for a Raspberry Pi running on Java, with some LEDs and an Adafruit LED matrix as output, and an Android phone as input device. Communication from Android to the Pi is done via websocket.

See it in action: http://www.youtube.com/watch?v=g_Mn1BiplmY

Supports scrolling text now, too, see this:

http://www.youtube.com/watch?v=JQi7WSU2Fak
https://twitter.com/slintes/status/420916372852318209/photo/1

Another update: added a Leapmotion client (see RLClient directory):

http://www.youtube.com/watch?v=DRHMy_JaD0A

Some links to used components and software:

Pi OS and LED matrix:

http://learn.adafruit.com/adafruit-raspberry-pi-educational-linux-distro/
http://learn.adafruit.com/adafruit-led-backpack/overview
http://learn.adafruit.com/matrix-7-segment-led-backpack-with-the-raspberry-pi/overview
https://github.com/adafruit/Adafruit-LED-Backpack-Library
https://github.com/adafruit/Adafruit-Raspberry-Pi-Python-Code/tree/master/Adafruit_LEDBackpack

Java:

http://jdk8.java.net/fxarmpreview/index.html
http://pi4j.com/index.html
https://github.com/TooTallNate/Java-WebSocket

Android:

http://actionbarsherlock.com/
http://androidannotations.org/

My libs for the LEDs and the matrix:

https://github.com/slintes/RaspiAmpel
https://github.com/slintes/RaspiAdafruitLEDBackpack

RaspiDroid

Install / Use

README