[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.

 

[HalloweenBob]

No video yet....I don't have a video camera. I'll have to try setting up my webcam to capture something.

I'll get something up as soon as I can.

 

[HalloweenBob]

If memory serves me right, the rod ends I purchased were part number 2458K111 fom http://www.mcmaster.com

The exact specs really aren't that important. Anything even close to this will work fine. The only thing is that the rod you slip through it must be the same diameter as the opening of the rod end.

The main piece that I had machined for me was the rod that sticks up through the ball joint rod end. I don't have a good picture of it yet, as the only one I have is mounted in the prototype skull at the moment, but here is a drawing I made and a description:

I don't have the exact dimentions, but as long as you make it to fit whatever coupler you are using and whatever rod-end you are using it will work fine. The actual dimentions should be something close, but are not that important.

The rod starts out thicker, somewhere around 1/4 20 bolt size at the bottom with threads cut into it so that it will fit in the threaded rod coupler I bought at the hardware store. The shaft extends up for about 3" or so and is then shaved down with a flare so as not to restrict movement as it goes into the rod end, but it keeps the rod end from moving any lower onto the shaft.

Above the rod end I have a thin spacer made of nylon. At that point, the shaft is threaded again. The threads match the two nuts that are attached here.

The portion of the shaft going through the rod end is not threaded. It probably wouldn't make any difference, however.

The first nut is tightened down over the spacer and holds the rod end tightly in place. Then a small aluminum arm is placed on the shaft with another nut on top to hold it in place. This arm sticks out towards the back of the skull and is for the servo which controls Rotation (left right movement) to attach to.

The very top of this rod has a small hole drilled in it in the center and it is threaded (inside threads) for a 4/40 screw. This screw can be seen in the picture in my first post. It holds the two armatures from the other two servos in place. They control the nod movement (up and Down) and the tilt movement of the skull. So there are your 3 axis'

I will post another picture of the skull mech including the jaw servo shortly.

 

[HalloweenBob]

To answer the question posted above, the shape of the Pirate Skull by Lindberg (http://www.lindberg-models.com/71302_pirate_skull.htm) allows me to drill a small hole behind the jaw and extend the rod end male threads through that hole, attaching a nut on the either side.

I had to bend the threaded end of the rod end slightly to acieve the correct angle. This was done by putting it in a vice, heating it up a bit placing a steel tube approximatley the same diameter around it and banging it gently with a hammer. Be careful not to damage the threads or snap them off. I would buy a couple extra rod ends for practice. I didn't need much of an angle, maybe 10 or 15 degrees. I didn't measure, I just did it by eye.

In that last picture, you can also see where and how I mounted the Jaw servo into the plexi plate and attached the jaw wire through a hole drilled in the skull. Exact location of the hole is not important. just find a spot that doesn't show too much and allows you to hook up to the lower jaw.

 

[HalloweenBob]

Yes, it is all one piece. My friend machined it on a lathe and added the theads, changed the diameter, etc.

 

[HalloweenBob]

Once I work out a way to video the whole thing, I will be glad to catch all the servos in action for you.

Has anyone else recorded something like this on a webcam? The software I have does not appear to allow me to record sound with the video.

I could dub it in later, but it may end up out of sync. My digital camera is old and does not do video. I'll ask around the neighborhood and see if anyone has a newer camera that does do video clips.

I have finished programming one skull fo one entire routine...except for the blinking of the eyes. I still haven't hooked that part up. I guess that part is next, Then I'll try to get a video done.

 

[HalloweenBob]

Go right ahead. I am just putting out this info to help anyone anywhere who wants to join the 3 axis club.

 

[HalloweenBob]

OK, I need some help here.

I took a video with my webcam of the entire routine (Just one skull so far). I was able to dub the music track back in using adobe audition. I really have no idea how, but it worked.

I don't have the editing software or the know how to edit this video. It needs to be compressed and chopped up into small segments. As it stands now it is just 3 minutes long and over 700 meg!!! And the quality certainly isn't DVD quality. I have no idea why it is so huge.

I am uploading it to my server now. Does anyone want to download it (I know it may take an hour to download!!) and do the editing, then post it back up here in a form that people can view?

Or maybe just tell me how to do it, but I don't think I have the right software. I wasn't able to cut it up in Audition, and was also not able to add compression. Maybe it's just me.

Anyway, I will describe a couple things about the video. The skull seems to bounce a little bit when it makes fast moves. This is caused by the stand it is on, not the weight of the skull verses the servos. If I hold it tight at the base, it does not bounce. That was one of the main reasons I went with this skull instead of the Bucky. It is so light, that the servos handle it easily.

The eyes have still not been put in. All in all, the programming has gone well.

I will still be tweaking it a bit. I apologize for the poor camera work. I was moving my webcam around and watching my screen to get some views of the servos in action. Since everything I see seems reversed from the way I move the webcam, it messed me up a bit.

Anyway, if you are brave and can help me with the video, you can download it here:

http://rewindshow.com/Download/3AxisSkull.avi

I think you will need to right click the link and choose "Save Target As" to download it as simply clicking it trys to play it.

Don't try to download it until about Noon Eastern Time or a few minutes past.

My upload speed is limited and it says it will take 2 hours to complete.

Thanks in advance.

 

[HalloweenBob]

Thanks Don...

Sorry to be so useless in video editing. I did some years ago with a very simple tool that stopped working after Windows 98. I'm lost with all the new editing stuff. I look forward to seeing my video.

PS... I tried encoding it as a DivX file. It knowcked it down to only 13 Meg and it looks fine, but the audio was several seconds out of sync!

In the avi I have posted, it is right on.

 

[HalloweenBob]

Any takers on helping me get that video up?

Twisted...Have you gotten anywhere with it?

you can download it here:

http://rewindshow.com/Download/3AxisSkull.avi

I think you will need to right click the link and choose "Save Target As" to download it as simply clicking it trys to play it.
It will take you 30 min to an hour to download the 700 meg 3 min long file.

Please refer to my post a few posts up for details.

Twisted, please check in. If you are able to get it done, then no one else will need to download, but if you are having troubles, please let me know.

 

[HalloweenBob]

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.

 

[HalloweenBob]

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.

 

[HalloweenBob]

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.

 

[HalloweenBob]

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.

 

[HalloweenBob]

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

 

[HalloweenBob]

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?

 

[HalloweenBob]

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....

 

[HalloweenBob]

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.

 

[HalloweenBob]

Right Click on the link to "TEMPLATE", and choose "Save Target As" from the right click menu. Save the image on your hard drive. I have added a bunch of lines on the left hand border of the picture that are exactly one inch apart. After you print the image, check it with a ruler to be sure that it is actual size.

Once it is saved on your hard drive, double click on the image and let the windows "Picture And Fax Viewer" open up. Click on the printer icon at the bottom and follow the prompts printing the item full page.

It should come out the correct size that way.

The servos I am using are Hitec HS-425BB servos.

http://www.servocity.com/html/hs-425bb_super_sport_bb.html

Most servos are the same standard casing size, however.

 

[HalloweenBob]

IMPORTANT Rod End Modification

At the beginning of this thread I mentioned that I had bent the threaded end of the Rod End to achieve the correct angle.

Turns out that was a bad idea. I must have bent the casing slightly when I did that, and the rod end became VERY stiff, exerting extra pressure on the servos making it difficult for them to move the skull smoothly.

I have rethought this and decided to make a minor modification to the skull which will allow me to mount the rod end at the correct angle without any alterations to the rod end.

Here is the skull before I started the mod. Note the shape of the neck hole:

That's a view from the top, now here's the same skull from the bottom:

Now I start the modification. I needed a heat gun (Which I had) and a pair of plyers with wide grip ends. You will see it in the pictures.

Setting the skull upside down on a piece of metal to absorb the heat, I started heating the area around the neck hole:

Once the plastic became soft and pliable, I got my plyers and grabbed the plastic area that I was going to attach the rod end into:

Very slowly, I moved the plyers upwards to change the angle of the mounting area for the rod end:

When I was done, it looked like this:

Then, I had to drill the hole for the rod end. I discovered that by changing the angle of that area, I no longer had a clear shot in there with a drill, so I used the edge of the drill bit to carve a small slot in the plastic which allowed me to hit the right area with the bit.


...to be continued