Hi;
For my after school robotics / electronics club we have decided to have a go at making some CNC plotters using a whole load of old DVD drives that we salvaged from the PC being removed from our school.
The project is based on
this Youtube video sadly the follow video has not been made / uploaded so we are a little stuck.
Here is the schematic:

I am not 100% sure how the whole thing operates (to draw a pic) but looking at the schematic there is no voltage being supplied to the Nano and the only power for the whole circuit seems to come from the USB which will be connected to a PC which I assume will be sending the data for pic.
Does this circuit need an additional power supply?
The circuit only seems to use L293D ICs as the motor drivers, most others I have seen use a motor driver board?
I just want some clarification on what is missing before I plug it into my Macbook and toast £1300 of PC!!
Here is a link to the code files etc:
https://www.mediafire.com/folder/mjpktcfixg4al/CNC_all_DataThanks in advance for any help