Mr. Hyde Halloween robotic top hat

Step 3 The lift mechanism

Dug North used parallel arms to lift his creature's head. I knew that I wanted my hat to be "normal" height so that nothing would give away the effect.

I decided on a scissors lift mechanism to raise it up. After experimenting with cardboard and paper fasteners, I came up with a good size to fit in the hat and yet lift up the head enough to clear the rim of the hat.

I used some vacuumforming styrene plastic I had handy. Anything relatively rigid and yet lightweight will work. I used #6 bolts and nuts along with washers and Loctite to create the pivot points.

The lower part took some working and reworking. I ended up using square brass tubing and creating a channel for the servo arm to slide along. A 1 1/2 inch #6 bolt connected the lower scissor lift arm to the arm attached to the servo. #6 bolts ran through a piece of luan (1/4 inch thick wood) with a spacer so that the long #6 bolt can ride along the length of the brass tubing.

I found a powerful but cheap servo on ebay (133 inch ounces) to run the arm. A standard servo wasn't strong enough to raise it.

I originally used foamcore for the base, but the servo was so powerful that it buckled the foamcore.