Cambot Season 1: Two infant seats from the early 80's, not that hard to find in a thrift store. A small block of wood, about 4in. by 2in. A red spray paint cap, and some Silver spray paint.
Cambot Season 2-5.5: I have no idea what this thing is made of... I faked it and it still looks good. look at plenty of pictures, and I rcomend using card board for the body, and pvc for the lens. A toy siren decorates the back of the 'bot.
I primed him pink, and painted him red metal flake.
Cambot Season 5.5-10: The body is made out of two fruit ripening bowls, turned on each other to form a spherical shape. The bowls I found were already the correct gray color... score! The lens is made out of some projector lens, but I used a black cup with a mirror over the front. I also placed black card board around the gap of the two bowls and put two red light bulbs next to the lens.