How do you get choas emeralds on sonic rush for ds

In order to get the Chaos Emeralds, you need to find the special generators hidden somewhere in the FIRST ACT of every level. In order to enter the special stage, you have to be playing as Sonic. Then, jump and grab onto the special generator (It's a little rainbow flashing wheel with a red and blue handle with a star in the middle. You'll know it when you see it.) Press and hold X to use your super boost. Do this until the rainbow ball above your head sucks you in. Note that if you do not have enough energy in your Tension Gauge then you will not be sent to the Special Stage. Then just get the amount of rings required while steering clear of the spike bombs.