# Servos for moving a head with a latex mask up and down.



## PumpkinBrain (May 7, 2009)

Hello all,

I've been fighting for the past few days trying to build a 2 axis head for a syirring witch. I'm using a pan and tilt system composed of two servos, one responsible for turning the head left and right and the other for moving the head up and down. The servo for turning left and right works perfectly but I have a major problem with the other one. The servo is able to move the head but at given a certain angle it lack resistance and the head goes all the way down until the servo is at the end of its range of motion. The pan and tilt system is placed inside a plastic skull on which I plan to put a latex mask. Right now, I get the problem with only the skull.

What would you suggest me? Would heavy duty servos do the trick? Maybe a wiper motor?


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## bfjou812 (Aug 15, 2008)

That's one option. Another is to build a partial plate that is used in the 3 axis skulls and just use the nod and rotate servos.


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## Dead Things (Apr 4, 2009)

I have had to use springs to assist the nod servo. However, this was with another design, different from the skull plate. It may be a matter of moving the plate until you reach a balance point.


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## halstaff (Nov 18, 2009)

What servos are you currently using? Could you provide a couple of pictures showing your set up?


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## PumpkinBrain (May 7, 2009)

I know it sounds stupid but I didn't thought about using the design of a 3-axis skull to meet my goal. I might try that. I don't have pictures of my design available right now and probably won't be able to take some until tomorrow. Meanwhile:

The nod servo
The turning servo
The pan and tilt mount for the servos

I put the pan and tilt mechanism inside the skull at around 2/3 of it depth from front to back. The mechanism is fixed on a 1/2 pvc pipe. Using a spring could probably help, not sure how I would fix it but I'll take a look at it soon.


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## darrylqmiller (Oct 22, 2012)

I have a spring at the back of my heavy skull I built years ago.  Bought an assortment pack of springs and just changed them around till I found one that worked good. One end screwed into the skull and one into the neck of the Bucky. Still works great years later.

Good luck!!


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## Batbuddy (Sep 3, 2014)

Not to hijack this thread but really have a look at the design of the three axis skull I did. It may help you with finding a solution. Most designs are done with super heavy duty hardware and are real overkill. Keep it simple and a bit loose in the joints. I bet the problem is because the pivot points are too tight and so the servo is trying to hard or something along those lines. Link to thread http://www.hauntforum.com/showthread.php?t=39931


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## halstaff (Nov 18, 2009)

PumpkinBrain said:


> I know it sounds stupid but I didn't thought about using the design of a 3-axis skull to meet my goal. I might try that. I don't have pictures of my design available right now and probably won't be able to take some until tomorrow. Meanwhile:
> 
> The nod servo
> The turning servo
> ...


Did you ever get this worked out?
The nod servo should have plenty of torque to do the job. I have many 3 axis skulls in my display including skulls that have been built up with clay and none of them require a nod servo with that torque.
The issue can probably be solved by changing the balance point. You can also adjust where the horn is attached to the servo shaft. Set it so the bottom of the nod range you want is at the bottom limit of the servo. That will keep it from going past that point and will make it easier for the servo to raise the head again.


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