Arduino code for sensors hub + programm to play the note for piano stair

Hi,


I'm looking at creating a giant piano on stair/floor (with sensitive keys).
- I'm particularly looking build The code for sensors hub / input receiver set on the Arduino
- software Program wrote in Processing that played the corresponding piano note mp3 sound
- The code for the audio
- How to put all together and make it happen.
Tell me wich output you could bring in this project.

Best,

here are example of the projects I want to do:
- https://vimeo.com/55533083
- http://www.ouest-france.fr/rennes-les-marches-du-metro-charles-de-gaulle-se-transforment-en-piano-425947
- how to do it: http://builds.cc/wiki/index.php?title=Musical_Stairs