this is a musical machine i built for astrids birthday, again using the same controller with three push buttons. if you press one of the buttons the canon will start and you can add the other voices accordingly. however, you need to get the timing right in order to sound like a nice canon. pushing the button again turns the voice off. (video link)
three push buttons in one controller, connected to arduino via ground and a digital pin each.
i’m using processing to do this, meaning that my laptop is actually playing the file, not arduino itself. here you can find the processing code i wrote. for instructions on how to get arduino to communicate with processing and vice versa, check arduino playground. also it needs the minim audio library installed.