# Spinning head ideas needed



## Severin (Aug 5, 2007)

I'm trying to put together a spinning head prop ala the exorcist but have hit a snag. 

I'm trying to get the head to spin a few times by motor and end up where it started. I'm using a pneumatic cylinder and a simple timer to have the prop sit upright and then lay back down. But I can't think of a cheap, reliable way to have the head end up in the exact place it started when the timer clicks off. I don't want the prop diving face first backwards into its pillow.

I've thought about using a momentary switch that triggers the head as long as the prop is upright, but its not exact. I think after the prop triggers a few times the head will end up in a different place each time.

Any ideas are really appreciated


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## Otaku (Dec 3, 2004)

What type of motor are you using to rotate the head, and how fast does it spin? Also, how is the head mounted? Is there an available section of rotating shaft in the neck? I have a couple of ideas, let me work on it for a day or two.


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## Dr Morbius (Sep 21, 2004)

mount the head on a sandwiched set of rotating disks like a little lazy susan, and attach it to the motor shaft in the neck. Make a circle of foil or some other metallic conducting surface that runs the entire outer diameter of the bottom lazy susan-type disk except for a small gap maybe an inch or so. On the upper disk, but facing down against the bottom foil circle, have a just a strip if foil, say a 1/2" wide. This will be your switch. Have your prop use a similar setup on the side as it sits up, making contact with another set of fiol strips that stops as the head makes it's first 1/4 turn or so. The metallic foil will keep the contact going for the motor and complte the head rotaion untill it hits the gap in the circle of foil. The only problem I can see with this is that when the prop sits back down his head will rotate again, but it will stop facing the right way everytime.


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## Severin (Aug 5, 2007)

Otaku said:


> What type of motor are you using to rotate the head, and how fast does it spin? Also, how is the head mounted? Is there an available section of rotating shaft in the neck? I have a couple of ideas, let me work on it for a day or two.


I have available a wiper motor at 65 RPM, a disco ball motor at 6 RPM, and a will be getting a battery powered rotisserie motor soon. (not sure of RPM on these, but I figure 5-6 RPM)

For the head I'm using a Styrofoam wig head that can accept a small length of PVC in the bottom.

The lifter is similar to this


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## Severin (Aug 5, 2007)

Dr.M, I followed you right up to the sentence below, after that I'm lost



Dr Morbius said:


> Have your prop use a similar setup on the side as it sits up, making contact with another set of fiol strips that stops as the head makes it's first 1/4 turn or so. The metallic foil will keep the contact going for the motor and complte the head rotaion untill it hits the gap in the circle of foil. The only problem I can see with this is that when the prop sits back down his head will rotate again, but it will stop facing the right way everytime.


I don't follow the part about a second set of strips or how the head will start to spin again after it hits the un-foiled area. Sorry if I'm being dense.


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## ScareFX (Aug 18, 2004)

This wiper motor would probably work. 
http://www.allelectronics.com/cgi-bin/item/DCM-249/400/POWERFUL_WINDSHIELD_WIPER_MOTOR_.html
Here's what makes it different...
"An interesting and possibly useful feature of this motor is that it always stops in the same position when the power is switched off. If a momentary connection is made, the motor will rotate exactly one revolution."


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## Mentalist (Sep 23, 2007)

Wow _nice_ find ScareFX!


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## Steve Filpansick (Sep 19, 2007)

Don't most wiper motors have a "park" terminal?

That's the terminal that used to make sure that the wipers only stop in the "down" position...


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## ScareFX (Aug 18, 2004)

Steve Filpansick said:


> Don't most wiper motors have a "park" terminal?
> 
> That's the terminal that used to make sure that the wipers only stop in the "down" position...


You are correct. They all have some way to park the wipers. But it appears this one might be easier to connect for that functionality.


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## uncle (Sep 26, 2007)

This Valeo motor is quite easy to use. Using this terminal, power can be cut to the motor at any point in the revolution and the motor will return to this set point. I used this motor in a MIB to allow the lid of the box to be in the down position between activations.


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## Severin (Aug 5, 2007)

Thanks ScareFX. I saw your old post at Halloweenforum about this motor right before you posted here  

Two questions. Did having a switch connected to pin 5 solve the movement problem? I know that motor has to weigh in at 4 pounds or so. Think there will be a problem lifting that, the prop body, and head?


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## ScareFX (Aug 18, 2004)

It worked fine using the diagram hookup after I switched power supplies. The motor is bit heavy. What size cylinder are you using?


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## Severin (Aug 5, 2007)

Bore looks like its about 1.25".

One other thing I'm concerned with is RPM. 65 is a bit fast. Do you think undervolting will slow it down some?

Thanks for the help ScareFX & everyone. Its really really appreciated.


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## ScareFX (Aug 18, 2004)

I've used 5 volts on the Saturn motors but not on this one. I would think it would work fine but I don't know...maybe someone else will chime in.


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