Quandary: Art Project Seeks Movement

[Entworthy]

Hello, and thank you in advance.
My friend is a glassblower, and I am a woodworker. He makes lovely ballerina pendants, and I had thought it would be nice to set one in a display that let the ballerina spin around. (point of contact being her pointed toe) I mulled the idea over long enough that it grew a bit too big for my engineering britches, but I am sure that there is an elegant solution and that the idea is feasible, hopefully I'm correct and you're feeling generous enough to enlighten me.

Idea: A small circle of Maple within a larger circle of Walnut,(Maple off center approx 1/2 of radius of Walnut) the ballerina would be set off center in the Maple.
The ballerina would spin clockwise, the maple would spin counterclockwise, and the walnut would spin clockwise. If I'm correct this will give the effect of a spotlight chasing the dancer around a dark stage.

I feel like this can be done with gears and a single motor, perhaps I need three motors, perhaps you can point or shove me in the right direction.

 

[Puma]

Maplins should have every thing you need in the UK. If you outline your project to the staff they should be able to guide you through.

 

[Entworthy]

West Coast USA, so I've never even heard of a Maplin.

Mostly I'm curios what the main form of mechanism should be.
Belts and one motor?
3 motors?
Clever gears and a spring?
Something else entirely...?

 

[Puma]

Well without seeing the design it's impossible to say which bits you will need.

I would personally try and avoid belts and have a couple of motors if possible. Belts will almost certainly cause one difficulty or another. To vary the speed of the components variable resistors, placed in series with the motor and batteries, are very cheap and will do a good job. You should try and pick up some conductive wire glue which saves soldering (if you don't have any experience of soldering).

Maplin is just an electronics component shop. The staff are pretty used to technical questions.

 

[CWatters]

A small circle of Maple within a larger circle of Walnut,(Maple off center approx 1/2 of radius of Walnut) the ballerina would be set off center in the Maple.

Perhaps look at a planetary gear set. Google images finds..

The outer ring gear is fixed. The motor drives the centre gear. The walnut circle would be mounted on the three planetary gear axles. The ballerina and maple would be mounted on one of the planetary gears which orbit around the center and rotate.

 

[CWatters]

PS. Looks like you might even be able to make the gears yourself...

https://woodgears.ca/gear/planetary.html

although it would be very fiddly at the small scale I think you need.

 

[CWatters]

Possible source of cheap plastic gears = Lego Technik.

 

[CWatters]

Last one from me...
http://www.instructables.com/id/Making-a-Laser-Cut-Planetary-Gear/

 

[jim hardy]

An old college friend of mine who's retired now has become quite expert at making wood gears.
As a woodworker you'll doubtless enjoy his youtube videos..
surely one of his kinematic gizmos will inspire you.

if the link doesn't work search on "ronald walters youtube"