This is a very expandable system ... it can be multiple channels on a rotating drum with multiple drums with gearing between the vertical and horizontal systems you can add more and more to create a very large array of percussive triggers ... I'm still tweaking the various different multiple systems.
Yes every part here is designed to be makde with a CupCake MakerBotable ... except for the rubber band ... get one from your local post office!
I wish I had a MakerBot to actually build and test my creations!
This is another of many entries to the makezine.com/go/makerbot contest ...