I decided to do the "newer" method of carving where you shave off the outer skin to let the light shine through the flesh would be perfect for the "orange" robot. I would also poke holes all the way through the pumpkin walls to let more light through for the eyes and other key areas for effect.
To start I printed off a drawing of the robot and taped it to the pumpkin. I then pierced the pumpkin skin with a small nail through the paper along all of the lines of the drawing so I had an outline of the robot on my pumpkin. After the paper is removed you cover the pumpkin in a thin coating of flour and rub it into the holes. This will highlight the pierced areas of the skin so you can then take a pen and draw the lines on the pumpkin but joining the dots forming a copy of what was on the paper originally.
Now the messy part, cut the top off the pumpkin and removes the seeds and "guts" and set aside in a bowl. Scrape more flesh off the inner walls of the pumpkin to make the walls thinner so the more light comes through the pumpkin where the skin is to be removed.
I used a wood carving tool to remove the outer dark skin of the pumpkin inside the drawn lines. For dark lines on the robot just leave the skin on in those areas. For really light areas or areas you want to highlight take a wooden skewer and poke it through the pumpkin wall completely this will let more light through and make that spot look very light. This gives you essentially 3 Shades of orange: dark skin, light carved to flesh & lights poked right through. This comes out especially well for the robot logo as the original is really only two colours but being able to add the "lights" for the eyes and buttons really makes it come to life.
That is it just put a light or a candle inside and you are all done! ---- Well unless you want some tasty Pumpkin Ravioli then just click http://www.instructables.com/id/Cheater-Halloween-Pumpkin-Ravioli-w-Caramelized-O/ for the recipe!