Once I had the main part of the body created, I moved on to the head which technically, is Minion himself. To do this, I first 3D designed and printed the structure of the head, I designed this to have several articulated points that would be controlled by Arduino. That would be the eyes, looking left and right, the eye lids, blinking, the jaw, opening and closing, and the fins, slowly moving back and forth.
Once I had the electronics worked out, I wrapped up the skeleton, and sculpted over it with monster clay to get the oter skin. I covered this in silicone, and cast this in a 2 part rubber mix. In hindsight, I should have made a plaster mould so that I could use liquid latex for the skin. This is because the rubber mix was more difficult to paint, and had to be spooned onto the cast by hand, and also ended up too thick for the jaw to move correctly.
THe dome over his head was made from an extra large propogation jar found in a gardening centre, and the metal sections of the body were made from EVA foam.
I wired the electronics to the inside and included a few fans as there is no air flow in there, and covered the body with a black fur fabric. The trousers section was attached to the upper body with a large open ended zip.