How do you get a chaos emerald in sonic heroes?

in each act of each stage, there is a warp module that has a star on it and two handles. To activate it: 1. jump on it(sonic will grab a handle) 2. hold down y to use super boost to spin the module(HOLD IT DOWN that's important) you need to have your tension bar to a certain point, which is about a bar and a half full 3. if you spin the module long enough, you enter a bonus stage. 4. collect enough rings and get a chaos emerald!
there are special zones in each level, beat them all and you have all the chaos emeralds