A smart keyboard instrument run on iOS. It is implemented on the iOS platform back in 2012.
This is part of the Chapter 4 of my PhD thesis
For more information on WIJAM, please check out this paper:
Deng, J. Q., Lau, F. C. M., & Kwok, Y. K. (2014). ArmKeyBoard: A Mobile Keyboard Instrument Based on Chord-Scale System and Tonal Hierarchy. In Proceedings of 40th International Computer Music Conference, Athens, Greece. (ICMC 2014)
Here you could find a demo of WIJAM.