Halloween Forum banner

My 3 axis skull...in progress

590010 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.
See less See more
2
  • Like
Reactions: 5
21 - 40 of 2218 Posts
The Video

Twisted has compressed my huge video for me.

He has posted it on YouTube, but the link isn't ready yet. He will post it when it becomes active.

In the meantime, I have uploaded the new smaller video in case anyone wants to download something of reasonable size.

This one is still the full 3 minutes, but is only 28 Meg.

Thanks, Don!

Here is the link:

Remember to right click on the link and choose "Save Target As" otherwise it will try and load and play in the browser....maybe with the smaller size that will work. We'll see.
See less See more
  • Like
Reactions: 1
I downloaded the HUGE one..LOL! Man, that looks FANTASTIC! Now I gotta try my hand at the "gimble" version...You can't beat the fluidity of the motion! Nice tune too...Exellent job! Oh, and welcome to the 3 Axis skull club!
  • Like
Reactions: 1
Link Is Up

I have it up on myspace and youtube here are the links
--------------------------------------------------------------------------------
----------------------------------------------------------------------------------
and youtube but for some reason on youtube the sound wont work yet.if it dont work with in a day Ill re-uplaod it for every one


working so far

--------------------------------------------------------------------------
hey bob what it the name of that song?

HERE YA GO AND ENJOY

THANKS BOB
See less See more
  • Like
Reactions: 1
A friend of mine let me use his Adobe Premiere Pro software.

A bit of a learning curve, but I was able to chop up the video into a couple smaller pieces.

The first one just shows some of the motion along with the music and is about 4 meg in size:

Right Click Here and select "Save target As"

The next one is about 8 Meg and shows the servos working while in motion and then some motion of the skull also to the same audio.

Right Click Here and select "Save target As"

And thanks to Don at Twistedvisions68, it is now up on YouTube with sound at this address:




Thanks for looking and credit for this project goes to Mike C for providing all the inspiration (as well as quite a bit of information and imagination!)

The song is called "The Headless Horseman" by Kay Starr

You can fnd it along with a bunch of others on my sound effects page HERE.

I will be posting quite a bit more on this as it all starts to come together.
See less See more
  • Like
Reactions: 1
Excellent engineering Bob, nice work. And a very easy to follow tutorial too, thanks!
  • Like
Reactions: 1
GREAT WORK !!!

And nice pics of the setup. It is a really clean, simple method you have there.

A note for not needing a custom shaft for others:
From the pics, I think using a piece of all-thread, with a couple nuts to lock against each other, a spacer, then the rest (rod end, spacer, nuts, servo connections) as shown in the earlier post would work fine IMO.

Again, nice work. Not sure if I will get around to building one, but I appreciate your work and sharing what you made.
  • Like
Reactions: 1
You are probably correct about the custom rod.

The reason I did it this way was that I wanted a heavier (thicker) rod extending all the way to the rod end (gimble) to add extra support so the head will not shake around when in motion.

You will see in the video that it does shake, but that is because it is not actually attached to anything yet, and the rod is longer than it will be when finished. Right now it is bolted to a small paint can filled with dirt.

I suppose you can buy a larger diameter rod end to accomodate the thicker threaded rod and go that route. I don't see why it wouldn't work. You would still need to drill a hole in the top and cut threads into it to accept a screw that would hold the two armatures in place, but other than that, you probably would not need any other special tooling for that rod.

Having an engineer friend with his own machine shop in his house, he designed it that way because he could. If you didn't have the tools to make one, the design would most likely be different, but would achieve the same thing.

Just make sure that the rod fits snugly through the rod end even if it is threaded, or you will get sloppy movement (and who wants a sloppy movement) and bouncing of the skull.
See less See more
  • Like
Reactions: 1
I know exactly what you mean.

When you got the tools available, why dink around trying to mesh other pieces together when you can do it the way you envision it should be done :)
  • Like
Reactions: 1
Very nice! How much? :D No, seriously. lol..
  • Like
Reactions: 1
What program are you using to control the servos? That's where I get confused.
  • Like
Reactions: 1
I am using Brookshire VSA (http://www.brookshiresoftware.com) to control the servos. I also bought an SSC-32 servo controller from Lynxmotion (http://www.lynxmotion.com/Product.aspx?productID=395), it can control up to 32 servos and is compatable with VSA. It runs off the serial port. In addition I purchased a Kit 74 Parallel card (http://kitsrus.com/jpg/k74v2_1.jpg) to control lights I want to run with VSA.

VSA is easier to use and understand than it looks. Once you read the FAQ's and play around with it for a while, you will be on your way.

Lynxmotion was VERY good with tech support. I called them and they answered right away and helped me get set up on the spot. A+ to them.
  • Like
Reactions: 1
HalloweenBob,

I just wanted to congratulate you on the design of your 3 Axis mechanism. Brilliant. What I love about it is the elegant simplicity. It uses an absolute minimum number of components and delivers maximum results. That's the epitome of good engineering.

You can see the mechanism I built for my skull on my website. Simple, but it only provides pan/tilt. I intend to build another skull for this year's show based on your design. Fortunately I can do the machining myself.

Did you come up with the design yourself, or were you inspired by anything?

Thanks,
PeterM
  • Like
Reactions: 1
wow awesome I dont think I have seen a talking skul with this much movement before great job.
  • Like
Reactions: 1
Thanks guys. I did design it (For the most part) myself. I had decided to use a rod end as my main motion component, and played around with layout if servos for some time. After I had decided on a layout, I came across Twisted Dementa's version of the 3 Axis Skull. It was almost identical to what I had laid out! After seeing that, I knew I was on the right track. (http://twisteddementia.com)

Anyway, I have been busy programming routines for the last few weeks. I have one complete and two others in process.

I have just now started building my other 3 skulls. I will be uploading detailed pictures in the next few days
  • Like
Reactions: 1
Can you tell me if you purchased the small aluminum arm or made that yourself?
  • Like
Reactions: 1
If you are talking about the small aluminum arm that extends from the center rod just above the rod end, yes, I made that. It was just cut from a piece of aluminum. Then I drilled a hole in the end and tapped it so I could screw in the linkage from the servo which rotates the skull left and right.

You could just drill a hole and use a nut on the other side if you don't have a tap set.

Was that what you were asking about?
  • Like
Reactions: 1
Yeap, thanks that exactly what I needed to know.
  • Like
Reactions: 1
I just finished making the additional 3 Plexi-Glass inserts that you mount the servos to.

I actually made them out of 1/4 inch Lexan.

Here are two of the finished products (I have 4 all together now):



Making these was easy because I was able to use the right tools!

My neighbor with the machine shop has a drill press with a CNC X-Y table under it, so the square holes were cut with a router bit in the drill press, and I adjusted the table which was holding the lexan from side to side and up and forward and back the cuts.

This picture is one I found on the net of a similar machine. I didn't take a pic of my freinds press.



Anyway, I used the drill press to cut the square holes and to make all the holes for the screws that I later tapped with a 440 thread tap bit.

I cut out the main outer shape with a bandsaw and then filed the edges with a buffing wheel.

The large center hole was cut with a bit similar to a doorknob hole cutter, just smaller.

I have an actual size template that you can download and print out. I used this template to cut all the pieces of Lexan.

First, I sprayed some 3M spray adhesive on the back of the paper template, then stuck it to the protective paper coating on the lexan. Once it dried, I cut a rectangle out of the lexan around the glued paper template making sure that the outside edges were parallel with the square hole cuts I needed to make for the servos.

So I had a rectangle shaped piece of lexan that had a piece of paper glued to it with my template design printed on it.

Here is the template:

TEMPLATE

Right Click on the above link and select "Save Target As" from the right Click Menu. Print the file using the windows Picture and Fax Viewer full page to get the correct size.
There are ruler marks on the left edge of the image. If they are one inch apart, then you have printed it to scale.


Here is what I mean by the edges being parallel to the square holes:



Then I was able to put the lexan into the CNC table and cut the square holes easily with the drill press. If they weren't parallel, I would have to make constant adjustments and would not have been able to make straight edges.

Here is what the plate looks like with a servo through one of the holes:



And finally here is how the plate fits into the skull:



The back end of the plate is mounted right at the top edge of the skull with two screws which go through the skull and into the edge of the lexan. The front is screwed down to the inside base of the skull between the eyes using the single hole at the very bottom of the template. It rests in the skull at an angle on purpose. When the lexan plate is parallel to the ground surface, the skull is lifted up slightly and seems to be looking straight ahead instead of looking down. This provides a "Center" spot with range of motion in both up and down directions.

This template is made specifically to fit the "Pirate Skull" by lindberg. It is a lightweight skull kit that can be found in many places such as this one:

http://www.monstersinmotion.com/catalog/product_info.php/cPath/14_228/products_id/10457



I will post more pics and instructions when I finish making the custom rods I will be using that fit through the rod ends.

More to follow....
See less See more
6
  • Like
Reactions: 1
I want one of those drill presses for christmas. I was so ready to get started yesterday and must have called 20 machine shops and they were too busy, so I have to wait till Mon to get started. I must have looked at your pic, drawing and videos a million times, but believe I can do this. I really appreicate the time you are spending on the how to's. Thank you
  • Like
Reactions: 1
I hope all my instruction is clear enough.

Perhaps I should have put this in the Tutorial and How To Section.

Maybe I will make a condensed version when I'm all done and put it there.

Once I get the new rods made (Hopefully next week) I will take detailed pictures of each step as I assemble one of these buggers.
  • Like
Reactions: 1
21 - 40 of 2218 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top