Terminator Eyes

Discussion in 'Replica Props' started by Conqueror_Worm, Jun 22, 2013.

  1. Conqueror_Worm

    Conqueror_Worm Well-Known Member

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    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
    [​IMG]

    Sectional Views: (the motor shows up as solid brass)
    [​IMG]
    [​IMG]

    Diaphragm:
    [​IMG]
    [​IMG]



    A few items that need to be sorted out:

    Fasteners:
    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.

    Motor:
    I need a small, slow, precise motor. Something like this would probably be great. It may even be TOO small.

    LEDs/Circuit Board:
    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...)
    [​IMG]
    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.

    Mounting points:
    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.

    Controlling it:
    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++.
     
  2. runnothide

    runnothide Well-Known Member

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    That my friend, is a work of art. Looking forward to seeing more.
     
  3. Sean

    Sean Sr Member RPF PREMIUM MEMBER

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    I don't even have a terminator head and i want two of them. LOL that is just absolutely awesome.please keep the updates coming....
    Oh and wouldn't the stops and starts of the little blu ray motor be a problem?
     
  4. gyoung2993

    gyoung2993 Sr Member

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    I am a huge terminator fan , I have an endoskull from Timeless collectibles and a Blu-ray endoskull that I was hoping one day to modify to have eyes come out for availability one day, I cant wait to see what your going to make, very excited to this being attempted, will be watching this very closely, cant wait to see more.....
     
  5. Conqueror_Worm

    Conqueror_Worm Well-Known Member

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    Thanks guys!

    Lets see, 20 steps per revolution, so 360/20 = 18 degrees per step. If it only takes 45 degrees to open or close the diaphragm, then 45/18 = only 2.5 steps to open or close the diaphragm. You're right, I'm going to need a motor with many more steps (or a different type of motor).
    I would also like to increase the amount of rotation required to operate the diaphragm, 90 degrees or more would be great, but I'm not quite sure how to do that. There is some really interesting math going on that I don't fully grasp. I could reduce the number of blades. That would allow me to lengthen the slots that the blades travel through, thus requiring more rotation to make the blades travel the extra distance.
    The original eye, used for closeups, had around twice as many blades as the one I designed (but it was also several times larger). So I don't want the blade count to get too low.
    [​IMG]
     
  6. Sean

    Sean Sr Member RPF PREMIUM MEMBER

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    Throw math at me and I run.very fast. LOL. best of luck on this.cool stuff
     
  7. TimePsycle

    TimePsycle New Member

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    Brilliant project!!

    Hope you see it through to the end.
    Only thing I could maybe suggest is if the motor actuating the iris
    was supported by the eye housing what we in the U.K call a
    swash gear (used to alter the pitch on helicopter blades) could
    be used off of the eye gimbals. You might find an off the shelf
    R.C helicopter unit of just the right size. This would give great
    animation to the eye ball.

    Best of luck, looking forward to updates!!

    Steve
     
  8. Crimson13

    Crimson13 Active Member

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    "I just need to make sure the FLORA platform isn't required."

    Flora isn't required, but some sort of microcontroller is. The easiest would be something in the arduino family, since they already have code for that on the site.
     
  9. Conqueror_Worm

    Conqueror_Worm Well-Known Member

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    Thanks guys! TimePsycle, that's a really cool mechanism, I'll have to keep it in mind. Looks like it's also called a swashplate. Crimson13, is it more than just an LED and a couple resistors? I found a copy of the schematic, I just haven't installed eaglecad so I can look at it.


    I decided to try 3D printing the outside casing of the eye, mostly so I could get a better sense of the size of this thing. I'm not sure 3D printing is the best way to make this, but as a 'rapid prototype' it works great.

    Printer: Makerbot Replicator 2X
    Material: ABS plastic
    Layer Height: .1 mm [.004 in]
    Infill: 75%
    Scale: 1:1
    Size: 25 mm [1 in] diameter
    Print time: 51 min

    Screenshot of software
    Side View
    Front View
    Back View
    Inside View

    I colored part of it with a sharpy to help the texture and detail stand out. Looks like I need to make the detail a little deeper. I've heard that ABS prints can be polished by exposing them to acetone vapors, I may try that to get rid of the print lines.
    Overall I was surprised at how well it turned out. It seems much smoother than most 3D prints I've seen. The scaffold it was supposed to print to support the back half collapsed, so the inside is pretty rough looking. There was also some warping near the beginning, so it took some time to clean up the mating surfaces so the two halves would fit together.
     
  10. Crimson13

    Crimson13 Active Member

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    Yes. They are "smart" LEDs which pretty much means they use a digitally addressable driver chip and can be chained together with only the same three lines (but you still control each separately). So it's more than applying power to one pin or another to get a certain color.
     
  11. Conqueror_Worm

    Conqueror_Worm Well-Known Member

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    Here is a small update:
    [​IMG]
    I picked up a couple of these for initial testing. I'm going to try using the MSP430 because they are cheap (free samples from TI), and I already have the programmer.
     
  12. Crimson13

    Crimson13 Active Member

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    Awesome! I'm glad to see an update on this!
     
  13. tim

    tim Sr Member

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    Nice! Did you get the devkit from TI with USB programmer? I need to fish mine out of storage and play with it some more.
     
  14. Conqueror_Worm

    Conqueror_Worm Well-Known Member

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    Yeah, I picked up one of the MSP430 Launchpads back when they were only $4.30. At that price I couldn't afford not to! Even if I don't know how to use it...
     
  15. DarkJerre

    DarkJerre Active Member

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    Any updates on this cool project?
     
  16. Conqueror_Worm

    Conqueror_Worm Well-Known Member

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    Not really, I haven't had much time to work on it. I'm currently researching methods for producing the parts; I'm not used to working with such small pieces that require such precision.
     

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