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need Help for construction of mechanical actuators

msrobotsmsrobots Posts: 3,709
in General Discussion
OK Folks,

I am a long standing forum member and I want to obey all the rules, so if I offend somebody or missing some rules I apologize upfront and am fine if this gets deleted.

For some reasons I can not explain here I got stuck with two live-size mannequins, both able to be posed to different positions of arms, legs, torso and head. Think about a live size Barbie Doll for the possible movements.

So there is a metal frame inside with joins but they are not easy to move since the mannequin needs to be able to stand on its own without much visible support when displayed.

What I want to do is to build a 'secretary' in my office, using one of those puppets I inherited, so I would pose it manually into some chair but I need ideas how to accomplish a couple of things to make the appearance more life like. Even if it is a Halloween idea, my ears are wide open, I have two of those puppets and no other use for them.

The first thing I need to solve is to move the Head so it could face a visitor. The Head is moveable to turn and to move up and down, but it takes two hands to do so. My current thought is to attach a lever at the back of the head and some actuators mounted to the chair, that would be mostly hidden from the unsuspecting visitor.

But either I need to loosen up the current mounting or I need quite strong actuators, those boebot-servos I have will not move anything. So I need some simple, practical and cheap ideas here, this is not commercial it is just for fun.

And - gosh - cleaning up my parents house is a challenge at it is, but how to dispose of two live like silicone based mannequins? Garbage can does not work and throwing them onto a landfill seems not to be a good idea either.

So I have to build something out of them.

For now the basic idea is that the puppet is sitting behind a desk in a chair. I even found a old electrical wheelchair but I am not sure if it is working.

The goals are to move the head and maybe move the arms/shoulders. That could be mounted to the chair and somehow hidden. Here we need quite strong actuators or smart ideas using steel wires and motors, I am open for any suggestion.

I still have some very small servos from those floating sharks @W9GFO(?) sold some years ago, I might be able to use them inside the eye sockets to move something, there is about a cubic inch of space inside each eye.

And then I need a idea for lip movement. There is some space to put actuators and a speaker in.

I try to be very careful here describing the mannequins, but they do look quite real and I am already smiling about the possibilities for Halloween...

Mike

Comments

  • frank freedmanfrank freedman Posts: 1,983
    The head turn may be pretty easy, ripping off some collimator rotation drives Siemens used in angiography labs. Collimators can be pretty heavy devices given the blades are lead, and the enclosure is also lead lined. Their method was to use a ring gear driven by a worm gear on a DC motor. Put a multi-turn pot on the ring for position sensing. Of course if you use a relative encoder and a zero tag instead of the pot, you should be able to spin her head like the exorcist movie.
  • idbruceidbruce Posts: 6,197
    Mike

    Your project definitely sounds challenging. Friction, weight, and length of objects, are the enemies. :)

    Of course, the complexity of this project will all depend on how much movement you want the "puppets" to have.

    For a project of this nature, I would certainly consider using pneumatic linear and rotary actuators, for the heavier pieces.

    For a wide array of actuator possibilites, visit bimba.com/
  • kwinnkwinn Posts: 8,697
    Surplus windshield wipers mounted on/in the chair may work for head movements.
  • localrogerlocalroger Posts: 3,451
    Seconding windshield wiper motors. Those things are powerful.
  • DigitalBobDigitalBob Posts: 1,513
    Your best bet would probably be a linear actuator with a ball screw and stepper motor.
  • msrobotsmsrobots Posts: 3,709
    Windshield wiper, yes, sure that might work and I do have two of the Parallax motor mount kits at hand from some other older project I could dismantle/reuse.

    But for the left and right movement and the up and down movement of the head a windshield wiper motor might be better. I need to unscrew a head and look if I can loosen up the neck join and attach some lever to it.

    That exorcist move is the most creepy thing of them puppets, the head is screwed to the neck on the body, so to remove it you have to grab the head and turn it about 10 times. And every round they are looking at you.

    Thanks for the link @idbruce, that might help a lot with movements of the arms, but I have no clue yet how to attach something to the arms and still hide it.

    I hopefully get the wheelchair next week to see how and what I can mount on the chair, but the chair looks pretty sturdy.

    One of the puppets is already missing one eye, I will try to measure the opening to see what I could fit in there. Terminator style camera?

    anyways, thanks for ideas, will follow up with pictures of the neck join on the weekend.

    Mike
  • YanomaniYanomani Posts: 1,524
    msrobots wrote: »

    One of the puppets is already missing one eye, I will try to measure the opening to see what I could fit in there. Terminator style camera?

    Hi msrobots

    When I read that post, I had one of those "déjà vu" sensations, pure "I've seen something like this before.." style...

    Well, if it had not to come from JonnyMac, from who could we expect something like this?

    https://forums.parallax.com/discussion/164853/def-con-24-uber-badge-powered-by-a-propeller-mini

    Hope it helps

    Henrique
  • msrobotsmsrobots Posts: 3,709
    ohh, Henrique this is wonderful. I remember seeing it before but forgot about it.

    Inspirational. But I do not think I have that much space in the eye socket. I have not explored that deep but as far as I can see the head is not hollow but filled with silicone, but if it is hollow that would make things more easy.

    Thanks for the link.

    Mike
  • YanomaniYanomani Posts: 1,524
    edited 2019-03-29 13:40
    Eh, eh eh... Imagination is the largest playground, at the universe.

    Well, if, at the end, you decide that space availability is still a concern and you also discover that the head movements need to be limited to a little rotational angle, perhaps you can use some ambience composition to transmit the intended message, like the movie industry has been doing, now for ages...

    Apart from Will Smith's "The Legend", at the video rent store scene, where he talks to a puppet, there are almost infinete examples, some very sweet, some not so...

    https://fratelliaifornelli.it/en/harvest-cake-from-drag-me-to-hell/

    Perhaps the best results you can ever get could come from some hidden cameras, disposed at the right angles, in order to capture the reactions of your family members and friends, when they meet the puppet in its place, for the first time...

    Ah, don't forget to ask them to sign a consent term, before broadcasting your productions. Your intention seems to be to widespread some joy, so don't start loosing your savings.

    Henrique
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