The Arduino can be used for many things when It comes to R2. The lights is a good reason to use one, as it makes them flash and do all sorts of interesting things. I have the Arduino Pro Mini and it only cost about $10. This is extremely inexpensive for something that does so much for our little droid.
![Arduino](http://www.buildanr2d2.com/wp-content/uploads/2016/03/Arduino.jpg)
You will see above is the Arduino Pro Mini and attached to that in red is the FTDI Break out, used for uploading a sketch to the Arduino. The sketch controls the lights and what they do.