Hello Sebastian,

A few weeks ago when discussed on the LAD a few enhancements for Hydrogen, one of them was to be able to switch between open, half-open and closed hihat samples when playing with the hihat foot control on an E-Drum.

In this fork https://github.com/blablack/hydrogen I worked out the basic backend solution:
- instruments can be set to be part of a hihat
- if they are, they have a range associated that say to what level of foot control pressure they react
- in the midi_input class, when a 'note on' is received, the method will check if the instrument is a hihat,  check the foot pressure and change the note played to the one of the right hihat instrument if needed

I still need to modify the GUI (at the moment I need to change the xml of the drumkit to be able to set that up), but if you could have a look at this to give me some feedback that would be great.

Thanks in advance,
Aurélien