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My 3 axis skull...in progress

590011 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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No questions, just WOW!


DB
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I agree...I was thinking why doesn't somebody doing the gimble thng use those rotating socket bolts? I see someone has! nice work. Got a vid? I'd love to see it in action!
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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.
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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.
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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.
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sweet

sweet bob you are the man, thanks for showing us this. and email more when you can
if you could show us a picture of the rod and neck mec with out the skull on it that would be great. Is the neck rod all one peice that runs up into the rod end? if so then I get the point.

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

cool thats what I thought. thanks a bunch again Ill keep an eye open for new pictures thanks bob
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I would like to see a video of not just the skull in action but the workings inside as its operating. Nobody has ever recorded the inside workings of their skull movements. I think it would help a bunch. And great job BTW.
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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.
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vid

I would not worrie to much about sound at this point bob. I think most of us would like to see it work. just do what you can.
Im working on putting one together now so with in a few weeks I should have all kinds of video up to help everyone out if you dont mind. also do you mind if I at this link to the fx lab
don
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Go right ahead. I am just putting out this info to help anyone anywhere who wants to join the 3 axis club.
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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.
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ok

Im downloading it know about 45 min or so Ill see what I can do to help ok
don
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watching

well that wasnt to bad about 35min at 265kbs Ill be back here in a bit..


ok I watched it, it wasnt to bad. nice work there bob for getting it out there for us. with it being a web cam there isnt much we can do about the grain in it but you can see what you need to see. thet the work begain. there will be lots of them coming up soon. once I get mine done Ill post it to.. post any and all pictures you have bob and Ill do the same..

thanks again for your time and work
don
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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.
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welcome

Hey no prob Im not all that myself . I dont have the time anymore to mess with much of this stuff any more. what kind of program are you looking for, if any. wow 98 se hehehe its been a while it seens like forever hehehe
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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.
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IM trying now

ok the link is this


youll have to wait for the vid to go into there system ok but it shoud come up soon. I have never use them before so I dont know how long it will take

bob I got it down to 28meg it runs the same on my computer but will have to wait and see how it comes out on youtube ok when it comes up Ill put the main link up ok
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