i just followed the basics from dan stowell's page, and built a reasonable sounding hihat in pd.
it has 100 resonating bandpass filters connected, and so for some reason needs a couple of 'hits' until all those filters let it work properly. also needs a couple of hits to get things working right when changing between presets.
pd's cpu meter tells me it's only using 1-2% here, but i am having trouble believing that. anyway, runs ok here.
patches attached.