Eye construction

Creating a fixed iris

When considering the eyes for the costume, I wanted to be able to have them react to light or movement. To do this, I will have to either control them manually, or create light sensitive circuits that could trigger some sort of drive mechanism. In either case, the shape of the iris would impact how I could open and close it mechanically. I considered looking for camera parts, but rejected this idea because of size limitations as well as the probable expense. The other shape I considered was a slit-type iris, and this should be much easier to create and control. When sketching ideas for this approach, I considered several possible mechanisms. The most precise would have used a gear drive to move two arms in different directions, allowing the arms to link to the two halves of the iris, opening and closing uniformly. I also decided it would be easier to sketch than to actually create such a precision mechanism.

I wanted the iris to be a crackle texture metallic gold. If I used camera iris mechanisms, I would probably be stuck with black or shiny metal coloring. The gold I envisioned was not just gold paint, but gold leaf. I also wanted a 3-dimensional shape to the iris, not a flat surface. The surface of the eye would need to be clear and smooth, both to protect the iris mechanism, as well as to appear more realistic.

For a start, I created a non-movable iris, one that I could always fall back to if the mechanics don't work out. For the test I used some 24kt gold leaf that I had lying around. I masked the central area that would be open to the back of the eye. A plastic ornament shell was painted with gold enamel model paint, then the gold leaf stuck to the surface before the paint dried. The inside of the dome was painted gold as well, to conceal tiny breaks between the leaf. Finally, the central opening was cut and removed because the masking had not prevented the paint from seeping under it around the edge.

Placing the iris inside another clear half-ball completes the eyes.

Fixed-opening eyes created by cutting an opening in 1/2 of a plastic ornament ball, then covering it with gold leaf. A second half ball is hot glued in place over the gold covered one to complete the eye. The pink square is the book of gold leaf used to coat the eye. Paper separates the thin sheets of 24K gold. The leaf was attached by painting an area of the ball with clear lacquer then touching the tacky surface with small pieces of leaf before it dries.

A red driveway reflector is hot glued to the back of the inside shell. The pink sheet is electro-luminescent film. Two pieces of film are cut to the size of the reflector, leaving a straight edge where the electrical contacts attach. Black masking tape is used to cover the exposed corner of the light film.

Forming a lens for the eye

As an experiment, I took one of the 100mm plastic balls and filled half with clear polyester resin. A smaller 80mm plastic ball was centered in the larger one, and weighted to sink it into the resin. During the setup, this looked promising. However, overnight the fumes from the resin fogged the inside ball surface, and the resin turned milky in reaction to the plastic ball. The result is obviously not usable for eyes, but has other potential, such as for large diffuse lights on some future project.

Fumes from polyester resin fogs the plastic

Since polyester resin is out for lens construction, how about epoxy? The pale gold of the epoxy looks interesting with the gold leaf iris. By using two half-balls of the same size, the epoxy combination creates a magnifying lens for the front of the eye.

The hemispheres are clear 100mm plastic ornaments. The iris parts were made from 80mm plastic ornaments. The dark red visible through the iris is a red driveway reflector (reversed, so the textured side is facing forward.)

Filling half of an ornament ball with epoxy and weighting down another half floating in the glue.

Movable iris construction

To create a movable iris, one or both sections would have to be hinged. I decided I could get away with a single section hinged, and the other fixed in place. The fixed section was hot glued in place on the reflector. Then, to get a more dynamic texture, I used hot glue to attach metal leaf instead of paint. (I found some of the inexpensive brass color metal leaf, after having creating the test 24KT gold leaf eyes.) Both sections were covered with hot glue and the metal leaf. Copper wire was bent to follow the curve around the fixed section, then bent outward at the ends to create hinge pins for the movable section. Holes were drilled at the points of the movable section, then slipped over the pins. A loop of copper wire was hot glued to the rear edge of the movable section to link to whatever mechanism I come up with.

The final result is a golden eye with a dark red pupil. The electro-luminescent (EL) backlight gives a soft, uniform red glow, but only where the back is exposed through the iris opening.

A special mounting ring was made to support the reflector and EL backlight, with a crescent shaped opening for the movable section to swing back through. The ring is large enough to hold the 100mm lens centered over the iris.

The final solution for the mechanism to move the iris was to mount a 12V actuator from the head frame so that when it extends, it pushes a lever that closes the iris, then pulls it open once power is removed. (The actuator is similar to the one found in cars with electric door locks)

A light sensitive circuit was made and connected to the actuator, and an "override" switch added to allow manual opening and closing of the eyes. When a light shines on the sensor, the eyes will close. The sensor is a small round light-sensitive resistor, concealed behind a clear faceted "jewel". Other foil-backed "jewels" will be mounted on the costume, to make the sensor less obvious. In dim lighting, the eyes should remain open, but in brighter light (like a spotlight) they should automatically close. One less thing to concentrate on during a performance.

Movable eyes are created in two sections. One part is glued to a red reflector, and the other is drilled at the tips for a copper wire hinge pin.

The hinged iris with an epoxy filled lens.

Mounting the actuator.

A close-up of the lever mechanism that opens and closes the iris.

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