I'm working on a design for a T-800 terminator eye with a motorized diaphragm and LED light. I'm still very early in the brainstorming stage, so if anyone has suggestions or critiques I would love to hear them. I'm still trying to figure out how many gadgets I can cram in a 25 mm sphere. I would love to stick a camera in there, but it seems like the light from the LEDs would make it impossible to get a decent image. (stupid impractical glowing eyes...)
Here is a video of my first design.
I used the GM15 motor from solarbotics. It's small enough, and should be strong enough for the job, but it has too many RPMs. The diaphragm only has to rotate 45 degrees to fully open and close the iris, but the motor does 920 RPMs, so it could open or close the diaphram in .008 seconds. It would be like a camera shutter. A motor around 480 RPMs would be better. On second thought, a stepper motor would be best.
Anyway, the motor mounts to the back half of the eye. Inside, the motor shaft is connected to a cup shaped piece that acts as a circuit board mount. The circuit board has six SMD LEDs size 0603. The circuit board mount has several pins that connect it to the back of the diaphragm. On the back of the diaphragm is a red translucent piece that helps to diffuse the light and make it appear more uniform. The diaphragm is a sandwich of overlapping blades between a front and back piece. The back piece has slots that the blade pins travel through when the back is rotated. The front of the diaphragm is secured to the front half of the eye, along with the lens.
In a nutshell, when the motor turns, it turns the circuit board mount, circuit board, diffuser, and the back of the diaphragm, causing the diaphragm blades to move.
Side View: with and without the covering
Sectional Views: (the motor shows up as solid brass)
A few items that need to be sorted out:
Right now there is nothing holding the two halves together. I could glue it but I would prefer to be able to take it apart. I'll probably make the eye halves a mm thicker at the equator and add a couple of tiny set screws.
I need a small, slow, precise motor. Something like this would probably be great. It may even be TOO small.
I was trying to decide between etching my own boards or having custom boards made when I found these. A 24 color RGB LED board in a package slightly smaller than the one I have in my model. More elbow room and multiple colors for only $2 a pop? You could have Arnie's red eyes one day and Cameron's blue eyes the next! (or green or orange or purple or white or...)
I just need to make sure the FLORA platform isn't required. I also wonder if I could get away without having a diffuser. Multiple colors would mean having a white diffuser, that might look a little weird.
Need to figure out a way to attach the eye to the skull. I could just have an attachment point at the back of the eye, but that doesn't seem like it would be very suitable for animatronics. Maybe I can make the equatorial set screws a little long and attach tie rods that connect to servos in the skull.
Making the diaphragm:
I think the diaphragm blades are going to be the hardest part of this project. I think I read somewhere that they are typically made from .1 mm spring steel. Really thin, hard material, with delicate curves, and tiny pins that need to be securely attached. My first thought was that I could cut out the blades by acid etching, then spot weld the pins on, but that sounds like a headache with lots of room for error, using tools I don't have. If I could make them from plastic it would be a lot easier. I could laser cut them at the local hackerspace, then just plastic cement the pins in place. I just have to find a plastic with the right material properties. The top and bottom of the diaphragm could also be laser cut or 3d printed (I may eventually make the top of the diaphragm and the front of the eye one piece).
Making the rest of it:
The assorted pins shouldn't be a problem. The two halves of the eye and the circuit board mount could be 3d printed or machined. I haven't looked at lenses yet.
I bought an MSP430 launchpad about a year ago, but I haven't done much with it. I'm just starting to learn C and C++.