Est. Budget: $50.00
Bad news first, I guess.... It has to be done by 10am Saturday morning, Feb. 28.
Good news is I am linking a page that has pretty much all the coding you will need for the interfunctionality between the two boards!
This only appears to take the initial commands from buttons wired to the Arduino instead of a sketch processing commands from other sources. (remote control via USB-bluetooth in this case.)
An example ...