Measuring RPM

[Tom Line]

In the case that you are unable to create a speed control routine in code, you actually can do a reasonably good job just by accounting for the battery voltage.

The major contributor to speed fluctuations of your wheel will be battery voltage, assuming that your motor and mechanical system don't change. By simply multiplying the amount your drive your shooter wheels by the % of battery voltage you can actually do a reasonably good job of keeping the motor at the same speed.

That said, if you use the "I" value in PiD, you can do a pretty good simple speed controller.