I started out by baking 2 half sheet cakes. Once they were cooled I leveled them off and iced them in buttercream icing.
I airbrushed it all black and did a lime green shell border around the bottom. I colored some icing grey and drew 3 squares and then smoothed it out.
I then added all the little details like the turn tables and buttons etc. I had made the headphones out of fondant and then placed it on the cake and drew a line with buttercream icing to the one control. I wrote happy birthday on it and called it done!