We came across a couple of Pong game projects built using potentiometers to control the paddles. They are not expensive, easy to work with and thus is a great choice as an input device.

We have a few of these interesting Rotary Encoder purchased from Sparkfun lying around for quite a while.

Here, we will be building yet another Pong game using two of the Bi-color LED Matrix Driver Modules daisy chained together driven by an Arduino Nano. We will be using rotary encoder to control the Pong game paddle instead of potentiometer.

Rotary encoder is much more challenging to implement as an input device as compared to the humble potentiometer. However, we would like to experiment with something
new here and hope that those who have not dabbled with them will get to know them better.

Detail on building this project can be found at http://www.instructables.com/id/Arduino-based-Bi-color-LED-Matrix-Pong-Game/

Video: http://www.youtube.com/watch?v=cAJEN9RsBiY