[LieAfterLie]

Very helpful. You might want to move the P code example showing the #define KP 5 / 10 to between the P and I sections though, as it doesn't show I control.

I finally learned what this PID stuff is about, thanks.

You might want to also mention that since motor velocity control is a speed you're comparing encoder ticks per time rather than a target value that has a defined range, and therefore also give us a simple method for determining the range, such as maybe start at this many ticks per time period as the min/max, then scale it down when the motor is full and gives less than that number, then printf that max to initialize it to for future code so that it starts out at the right range. I know this really goes beyond the basic PID concept, but it is relevant to speed control.