Halloween Forum banner

My 3 axis skull...in progress

589574 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
  • Like
Reactions: 5
61 - 80 of 2218 Posts
...But how much will it COST??

I thought I should take a minute to document how much money you might be spending to duplicate this project.

First, I will list a bunch of misc. items that I did not pay for, because either myself, or my friend with the machine shop had laying around, so I didn't buy them, and I am not sure of the cost.

These items are as follows:

Tools - Including hacksaw and blades, heat gun, drill press, band saw, lathe (or the cost of hiring a machine shop) as well as standard tools, like screwdrivers, plyers, cutters, a vise, etc.

Hardware - Extra pieces of steel, aluminum, welding wire, Threaded rods, nuts bolts and screws, stain and paint, and whatever material you will use for the skull's body and clothes and a wig or hat if you decide to use one.

A computer to run it all. (I did buy a dedicated machine for this, but it was an old used one from ebay for about $50.00 plus shipping. You may have an old one laying around.

Wire to extend all the servo wires with to connect to the controller board. (I also bought multipin plugs and jacks to make the connection modular)

Lights and a kit 74 or similar board if you plan on using it to enhance your setup. Cost will depend on how extravegant you plan to get.

Now for the tangible costs.

First, the skull itself. The Pirate Skull from Lindberg is between $15.00 and $20.00 at most retailers. We'll go with $20.00 because you will probably be paying shipping as well...so:

skull - $20.00
5 servos - $70.00
Sheet of 1/4" Lexan - $18.00
Rod End - $9.00
Servo Linkages - $4.50
Bag of wooden balls from Michaels to make eyes with - $3.00
Brookshire Software's VSA - $55.00
Lynxmotion SSC-32 Servo Controller Board - $40.00

...not letting your wife find out how much you spent - Priceless!

Total cost for one skull like the one I am detailing in this thread not counting the misc. materials and tools mentioned above: $219.50

I wanted you to be prepared for the costs involved before starting.

I am buliding 4 of these suckers! Of course, I only need to include the cost of the computer, VSA software, SSC-32 borad, kit74 board, sheet of lexan, etc once. They will control ALL the skulls, so the main expense for each additional skull is the servos, and the skull itself.

Hope that doesn't scare anyone away! I know we don't scare easily around here.
See less See more
  • Like
Reactions: 1
It's an investment! And you also need to get the beefy power supply for the servos.
  • Like
Reactions: 1
Forgot about the power supply!

I bought a 5 AMP 5 VDC supply on ebay for about $40.00 after shipping.

Actually, it has one 5VDC 5 AMP output and 2 adjustable 2 AMP outputs - (0-12VDC)
  • Like
Reactions: 1
...not letting your wife find out how much you spent - Priceless!

Or husband...hehehe
  • Like
Reactions: 1
Hey HalloweenBob... can you let us know what Power Supply you are using specifically? Thanks...
The exact type of power supply isn't all that important. What is important is that you have one that produces 5 or 6 volts DC with plenty of current.

I hope mine is good enough for the task. I haven't tested it with all four skulls running at once. I hope to have all 4 skulls put together and ready to test next week.

My power supply is giving me 5 VDC at 5 amps. It also has two additional outputs which can provide 0 - 30 VDC at up to 1 amp each. I use the 5 AMP output for all the servos, and the other two outputs power the SSC-32 board and the Kit 74 board. (Earlier I said the extra two outputs were 0-12 VDC. That was a mistake. They are 0-30 VDC and each output is only 1 AMP. I was writing from memory and hadn't looked at the actual unit first.)

Here is a picture of what I am using:

I found this on ebay while searching for DC power supply. It was a good price, so I bought it. Not very compact, but that isn't a problem in my situation.

I will report back to let you know if a 5 AMP output is good enough to run 18 servos as soon as I get to test it out next week.

Does anyone know off hand if I have made a mistake, or will the 5 AMP 5 VDC output be enough?
See less See more
I hope not, 'cause that's what I plan on doing! Well, two 5v 3A power supplies. Do you need to do anything special to keep your servo controller cool? I was thinking of putting in a muffin fan.
That is like the one I was looking at. I was curious to see if you had a smaller one or not.

The HS-425BB use 180mA (no load operating). So you should be able to power around 27 servos with the 5 amp PS.... right?
I guess you are right with those calculations, however, they will all have a load.

I hadn't thought of heat issues with the controller. I actually never checked to see how hot it gets.

Does it get very hot?

Again, I have not tested it yet with all channels running.
Not sure how much juice you need for the servos, but you guys might want to look at an atx power supply.

It will give you 5v and 12v.. i think 3.3v too?

The real plus is it's regulated, especially the 5v where all your money is. I think the 5v is ±5% and 12v is ±10%

Be careful with cheap transformers, the dc output will vary with the line voltage going in.

Bob has a nice bench transformer which is giving him clean power.

Why do i know this.. I am looking at using it to power some blacklight LEDs I'm tinkering with (look for a thread on this in the coming weeks).

And thanks for all the info Bob. Don't think it's something I can tackle this year. But it gives me something to think about at work.. er during my lunch break :)

See less See more
How much current does an ATX power supply put out at 5V?
The power out will ultimately depend on what size ATX power supply you use. However, the 350w ps I have will do 32A/185w at 5v and 26A/312W at 12v. Of course these are not concurrent; the max output cannot exceed the rating of the ps.

The nice thing is that most of us have.... or know somebody who has.. an old computer laying around that you can scavenge a nice power source from.

32 amps would fry my servos..wouldn't it? I'm only using 4-6 at a time. do you use resistors to limit the current? Ooops I didn;t mean to hijack this thread. Sorry, HalloweenBob...This is my last post here on the subject. Looking forward to seeing your eye mech!
doc, a high amperage power supply will NOT fry servos or any other device. a device will only draw the amps it needs to operate. There is no need to place resistors in the circuit.
Thanks spookster..I'll try an ATX...Heck I have about a hundred of em!
Center Rod Update

My friend finally got me the rest of my center rods so I can put this whole group together.

I wanted to outline this part for everyone as it is the central part to the whole project.

First, Here it is completly unassembled:

Here are the dimensions and specs:

The only part that is missing is the rod end. The rod end is part of this assembly, but it is already mounted in the skull, so the center rod needs to be assembled in the skull.

I will go through the order of assembly outside of the skull because it is easier to see that way. The only step that would be missing would be the first step where the rod is inserted into the rod end that is attached to the skull.

After insertint the rod into the rod end, you would take the beveled spacer.....

It looks like this:

and slip it over the top of the center rod with the beveled side down like so:

The rod end would be filling the space you see between the bevel at the top of the wide portion of the center rod, and the beveled spacer. The rod itself, the beveled spacer and the rotate armature (Which I will show later) were all custom machined for this project.

Next we add a nut over the top of the Beveled Spacer to hold it tight to the Rod End so we don't get sloppy movement.

Now it's time to add the Rotate Armature that I cut out of steel earlier in this post. Here's how it goes:

Now, another nut on top of the Rotate Armature to hold it tightly in place so it won't move:

Just to show you, this armature has a small hole which was tapped for a 2-56 screw which will hold the rotate servo linkage. That screw goes in here:

See less See more
Now a look at the very top of the center rod. It has a small hole drilled in it which is also tapped for a 2-56 screw. This is the hole that you attach the tilt and nod servo linkages to. The two linkages sit on top of the rod, one on top of the other, and the screw goes through them both and into the rod:

You can see how the screw goes into the top here:

That's the whole thing for the center rod.

Here's how it goes into the skull. Remember, we left out the rod end step since it was already attached to the skull.

Then, flip the skull over, and add the beveled spacer over the rod end like so:

Just follow all the steps laid out above, adding all the pieces in the same order with the skull and Rod End now in place.

As soon as I get all 4 skulls put together and tweaked, I will post another video with them all going.

...Any Question?
See less See more
I have been following your work, and I was wondering what happen to the pic's in the post. number #79. The work you are doing is so cool. Good Luck.
I see all the pics in post #79. Try refreshing your page.
My wife took a picture of me working in my makeshift workshop. My basement.

Here's what it looks like so far:

Just me and my friends hanging out. I am busy tweaking and adjusting VSA commands.
See less See more
61 - 80 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.