I am currently designing a tennis ball launcher. I am looking to use the friction wheel approach, where you have the ball passing through 2 spinning wheels and being launched by the frictional force. It needs to launch the ball up to 20 meters. So, for now, I am using RS555 Motor - 12V motor for both of the wheels in my design.
I believe it is a brushed DC motor. I want to be able to control the speed of the motor with a knob or switch on the side of the design. However, I am admittedly lacking in my knowledge of motors and motor components. What components do I need, aside from the two motors themselves, to operate the motors this way, so that I may incorporate them into my design?
And if I decided to not use variable speeds and just want the motors to operate at a constant speed, what components would I need?