Linear positioning

Hello,
ik would like to build somthing like this: http://users.pandora.be/Ivevanlee/helpme/Untitled-1.html
many off-the-shelf stuff works only straight and I would like to build a
cheap version myself. If there is a good off-the-shelf product I would very much like to know about it!
Controlling a stepper trough a computer is no problem and I have programming experience. Just absolutely no engineering experience :) Can anyone point me in the right direction or answer questions like: - is connecting a stepper the right way to go? - what kind of wheels should I mount on the stepper? - what kind of rails should I use? - are any of these components easy to find?
any information you could give me would be welcome!
many thanks,
Ive
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Ive wrote:

Have a look here:
http://www.hepcomotion.com/db_pages/products/prod_list.php?cat=circ
Driven ring & circular track systems, may be appropriate or not. Not cheap though!
Peter
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Peter Neill wrote:

That's exactly the information I was looking for! And yes, it is rather expensive :) I'm a student, I would rather build it myself.
http://www.hepcomotion.com/db_pages/products/catdl.php?cat=PRT_SC
so if i'm not mistaken I can either: - use a rail and wheels, connect a belt to a motor and the platform... this is not an easy solution i think.. - a rail with teeth and mount the computer controlled motor (and cogwheel) on the moving platform.. this is seems like the way to go.
where would I find rails with teeth on them?
Ive
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Errr,..... Hepco?
If you need something cheap and it's not taking much load, than how about some model railway track instead?
Peter
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Ive Wrote:

Shouldn't your first question or information be what kind of accurac do you need? And a second being whether the system is limited to that arc or othe things. is it a CNC tool or train that you hope to build?
If you are limited to the arc, then a solution might be to drive swinging arm by a pinion, belt drive or other appropriately geare system rather than a mechanically accurate track
If its a train, you might get away with a simple servo wheel driven b the track, rather than a precise and expensive mechanical system, o even a pair of position calculators (think sonar or laser or even a se of those wire DRO's) that can work out the position.
Robi
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