Jeux d'orgues is a neat application that contains a number of French organ samples (link here). There's also an iOS version and Android version (called Opus 1). Using a class compliant USB-MIDI adapter or alternatively directly connecting to the USB-MIDI port, it is possible to play the instrument using external controllers.
Here we see it in action with my Yamaha CP-33. The neat thing is the app supports MIDI CC/PC mappings to trigger different stops, which means I can change them using the built in patch keys of the keyboard!
I was fortunate enough to have access to a MIDI enabled Casavant organ at our church. The organ is a fascinating instrument in many ways, but one particular is the fact that it was the first instrument where you can change the mapping between the input and output on the fly, and that is an otherwise exclusive feature of new digital musical instruments.
With the ever-improving Leap Motion SDK, and some work related motivation to "yarpify" things, I got the following running after struggling with some typos in my SYSEX messages that are used to control the organ.
The above shows one simple mapping: X (left right) controls the pitch, and moving the hand forward goes from no sound, to a single stop, to a second stop that's making notes a third higher. What was immediately interesting was that the digital control of the organ is extremely fast, and glissing through in this manner created runs that are basically impossible to do on a standard keyboard (well, maybe if you practiced some two-hand technique where you can time the black notes in between the white ones...). Also, it was very apparent that a simple linear X-position to pitch is highly unnatural when you don't have the tangible feedback of a physical, rectangular keyboard.
