you are going to need:
Sheets of "Fun Foam"
a Styrofoam ball (Ours was about 9 inches in diameter)
thick paper plates
an LED push-button light
a spinning stool-chair-thing
determine the size of your Styrofoam ball. you need to measure the circumference and diameter.
Make sure you have enough "Fun Foam" to fill the dimensions of [Circumference x diameter]
hot glue these pieces together so that it forms a sphere-ish shape (don't glue the last two together yet)
We researched from multiple sources, but this site proved the most helpful: http://www.turbosquid.com/3d-models/wheatley-video-character-robot-3d-model/602446
We used foam to cover most of the sphere. We also used it for various detailing elements.
By this point you could call your model complet e. You can carry around your Wheatley with your portal gun, or launch him into space just for giggles, but we took it a step further and made our model connect to the ceiling like Wheatley does when attached to his rail at the beginning of Portal 2.
Step 8: EXTRA STEP 1
Step 9: EXTRA STEP 2
AND YOU ARE DONE!!!! Go admire your Wheatley model while playing your favorite video game. Testing will never be dull with this exciting little guy in your room. He may be an idiot, but he will be your best friend. (Other than the companion cube, of course)
This model can also be used to make any of the Personality Cores from the game Portal 2 just by coloring the LED light differently.
So what are you waiting for? Go make yourself a great Wheatley!!!