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?


2 Answers 2


I recommend researching motor driver circuits. These motor drivers internal has a H-Bridge design and have both direct on of digital signal to manage both direction (forward, backwards) and stop. You will also need a micro controller to control the motor driver.

Below is an example block diagram for you to visualize.

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Below are few good places to start researching. Similar sources like the below some times have almost ready made designs. Mostly likely you will have more questions. Come back here with your research details and questions.

Note: There are plenty of other options.


  1. Pololu Electronics Motion Control Modules
  2. Sparkfun Motors and Drivers - DC / Gearmotor Driver
  3. Adafruit Motor Selection Guide

To the suggestions given by Mahendra Gunawardena, I'd add to use only one motor, with pulleys to power both wheels. It's simpler and cheaper and it ensures that the two power wheels will operate at precisely the same speed, which may be a problem with two separate motors.


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