Stairway lightning 

This video shows an automatic stair lighting, controlled by an Arduino and two motion detectors. The motion detectors are placed on top and bottom at the stairway.
Every time when somebody uses the stair, the controller switches the LEDs on, depending on the direction the stair is used.
For further information (like circuit diagram, etc.) take a look at my website: arduino.joergel...
(My website is in German)