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My 3 axis skull...in progress

589585 Views 2217 Replies 203 Participants Last post by  HalloweenBob
I have a couple of pictures of my prototype. I will take a bunch of new pictures as I make the other three skulls, but this should give you an idea of what I am doing.

I am making a singing quartet based on (That means idea stolen from) Mike C's Graveyard Quartet. Ever since I saw his video I couldn't get it out of my head.

A neighbor of mine with a machine shop has helped me with the prototype, machining some of the parts I needed, and helping with the design.

I have been using the prototype to do some programming to make sure it all works with Brookshire's VSA software. So far, so good. I will post detailed pics of every step as I start making more skulls, but for now, here's a couple of basic shots with labels on them.

The Jaw servo was not mounted yet in this pic. It is in now. You can see the mounting screws and the linkage wire in the pic. The servo mounts standing up on end. I will add pictures of that later. The eyelid servo is mounted under the plexi-glass. That one is not hooked up yet, but when it is, it will be attached to one of the eyeballs...I am using wooden balls for eyes. It will move it up and down, not side to side. The purpose is to make it appear that it is blinking. I have large fake eyelases that will be attached to the eyeballs. When the eye is moved down, it appears to be closing as the top eyelid moves down with it. In the pic below, you can see the slot cut in the eye socket where the armature will go to move the eyeball. Don't worry, I will post pictures of that as well. I am using a 3/16 rod end as the gimbal which allows movement in all directions. When I build the next one, I will have clear shots of that as well.

Feel free to ask questions, and I will answer as best I can. I now have it hooked up to VSA and it is working very well. I am using the lightweight Pirate Skull and so I do not need springs, elastics or counterweights.
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Replying to Inspirational and Questions....

Thank you so much for reading through it and following my work. As far as the v1 build, there are templates within the thread, but I haven't really put it all together in one place as a parts list and instructions. I probably should. That would be the kit to build if you are beginner to novice with animatronics.

the v2 kit never had official paperwork from me. I built the prototype without any drawings, just an idea in my head. I made the first part, held up servos to it to see what would fit, made a second part, revised it and so on until I had something that worked. Then I sent it out to Joel in California when Graveyardskulls was still a thing. He took the design, made a few modifications to reduce it's height and created templates for it so the parts could be made in a CNC machine. He never gave me any of those files, and the parts would be very time consuming and difficult to make by hand, the way I did with the prototype. I have some new designs in my head, but I'm waiting for some things to fall into place and to get a 3D printer before I start making new prototypes. I will, of course, post here once that happens. This will be a much-improved system and entire skull and will be v3 for my 3 axis design. What I could use, if anyone is reading this who can do this kind of thing, is someone who can translate my ideas into 3D CAD drawings that can be 3D printed. Anybody out there good with that? Please contact me if you are.

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I want to say thank you for all of your ideas and help given to me to fix my skull operations problems. Turns out that the problem must have been in my power supply on the 5V rail as suggested - it did meter out at 5V no load. So I used a big bench top power supply I have for other work/testing and it all ran fine at 6V. I had been using that ATX power supply (I do have a sandbar resistor in it) and the 5V rail to run the: SSC32, servos and the LED spot lights and the 12V rail to run effects lighting through a K74. I had been using 5V for years but this time it just did not work. So here is what I did, I swapped my wires to take power from the 12V rail and inserted a LM2596 DC-DC converter which I dialed down to 6.25V, .25 extra for the long run of my control cables and 22AWG wire. I ran my full show with no problems this morning.

I've been 'out' and now that I've done everything above I am finding your note --with tons of great info!-- saying separate the VL/VS power. I have not done anything since this a.m. due to other works in progress, based on what I have done above do you still think I need to split VL/VS power?


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No, if you're running at 6VDC, it's fine to leave both VL and VS together. At 5VDC, it can be a problem. Sounds like you are doing fine.
Thanks again Bob.
What I really mean is "I can't thank you enough for all your help"!!!!!!
You've saved my show this year.
Now I'm off to the grave yard 'troncs.
I think I need to stop trying to add one new thing each year, it's becoming monster (pun intended) to manage!
Happy Haunting!
Not to down play the lengthy advice you got from HB but I, as well as bfjou812, said at the very beginning that it sounded like a power supply problem. ;)
Hi J-Man.
Yes you did and I did not intend for you or bfjou812 to feel ignored, it was a matter of time. With my job some days I'm home, some days I'm not and I had not checked my email before I started trying things as I was in a rush and scared I would not have my prop for the show. On the other side of the coin the original project here was by HalloweenBob and I have followed it from the start way back when he started this thread in 2007.
So if you will I got the skinny about the Monster direct from Dr. Frankenstein ;). Also I received even more information from him when he responded on possible future problems, again as he started this thread in 2007 he has the most experience:

1. Extension wires are too long and the signal to the servos is being degraded through the length of the wire (15 feet or longer may be too long)
2. There is a lose or disconnected ground wire somewhere in the system, probably on the SSC-32 card
3. The power supply does not provide enough amperage at the output to drive the number of servos/LEDs that you are using.
4. There are power wires running along side your servo extension wires which are causing interference with your signal wires.
5. The SSC-32 board has developed a problem
6. One of your servos is going bad, but is still functioning. This will put an increased drain on your power supply, causing random problems throughout the system. Check to see if any servo is getting hotter than the others, or one at a time, disconnect a single servo and see if everything else improves. If not, connect that servo back up and try disconnecting a different one.

Off the top of my head, those are the most common issues I have run into, and through the years, I have experienced every one of those issues at one time or another.

I keep all of my project data on hard drive and thumb drive backup (Christmas too, another big show) so this info., and yours, went into my note book for future reference.

I received a lot of responses, public and private, and "I thank everyone for their help in my moment of need/stage fright"

because -- The show must go on! :D

In closing I hope you, and everyone else, have an awesome Halloween!
Thanks again.

Not to down play the lengthy advice you got from HB but I, as well as bfjou812, said at the very beginning that it sounded like a power supply problem. ;)
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Glad you're up and running! Happy Haunting!
Good to hear you are up and running. Like you I also built 3 or 4 skulls using HalloweenBobs method. He is a real help when it comes to getting things figured out. He helped me on some programming issues I had. Like you said , He' the one with the most experience on this build.
Been looking at 3D printers this morning. May have a nice one in place that I can use some time this summer. I will post here as things develop. At least then I can start working on new prototypes.
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Are you thinking about rolling your own Skull with the 3d printer? Or is it for fabricating the internals?
Most likely a combination of both. Some parts will be metal, and some parts will be plastic, but might be easier and cheaper to produce in a shop with a CNC machine. Still trying to figure that all out. I will be 3D printing everything I can for the prototype whether it ends up being done that way later or not.
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I've been interested in trying similar. Mills are still capable of producing stronger parts, but for light-load parts or for prototyping 3D printers open a lot of possibilities. I'll be really curious to hear more about what you come up with.
Electronics Machine Technology Electrical wiring Auto part

Here is a picture of my ver2 and ver3 of a 3D printed skull base. I have more parts on the way for ver4. I find that the spring in the neck causes the servos to growl more than I like, so I will be using a swivel joint for the next version.
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That looks like pretty nice work. I'm guessing the grey (or silver) parts on the table are part of a different project.From the pictures, I can't see the spring you are talking about. I like the original design, however.
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Here it is without all those distracting robot parts in the background.

You can see in the picture how the spring is bent by the servo action. This is similar to the 'twisty' system. I am replacing that with a universal joint. That will remove the pressure from the servo, and thus should make it smoother and longer lived.
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It all makes sense now. the old Twisty Skulls used to use a spring center. If it's making the servos work too hard, perhaps you can just find a less aggressive spring to use. Nice job on the 3D printed parts. Do you print them yourself, or send them out?
I printed those myself. This design is printed in ABS. I had some problems with the last print lifting from the bed. But it did not affect the functionality. I expect many more versions before I am satisfied with the design.
What 3D printer do you have and are you happy with it?
Are there any working links to audio files to use with these skulls? I built one back is 2010 and only used it then. Thinking of pulling it back out but would like some pirate theme monologue this time around. Even clean stuff from the POTC ride.
Please let me know what links are not working and I will try to fix them. There are a lot of links, and it's a long thread, so finding them myself would be very time consuming, but I'm pretty sure I still have all the files referenced.
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