I think using an RPi here is a bit overkill (what no arduino?). But still this is a nice simple build you could do for a drawbot. And I think this design is easier to put together than some of the other CDROM ones I have seen over the years.
http://makezine.com/2015/07/20/build-drawbot-two-cd-drives-raspberry-pi/
Detailed directions here:
http://www.homofaciens.de/technics-machines-plotter-cdrom_en_navion.htm