How do they do this? Any idea?

[HankMcSpank]

Would something like this work or along these lines?

That was very innovative.

Actually, a pickup winder was my first targetted PIC project. I used an old cooling fan as the main motor (printed an encoder pattern, then stuck that to a CD, which in turn was stuck to the fan motor) & I used an old dot matrix printer's stepper motor as the traversal motor.....it worked surprisingly well, but you really need floating point as you end up dealing in a lot of fractions to get the traversal going accurately enough.

Speaking of traversal, that was the weak pount of the guy's solution in that video - terrible resolution (as the traversal changes direction, you've got the diameter of that large hole the wire is threaded through introducing large amount of innacuracy).

I'd recommend a helix type traversal solution along these lines (which is what I used)....



Simpler too.

Knowing what i know now...I'd strongly recommend just using two stepper motors... one reasonably powerful one for the main turning motor and a smaller one for traversal. It makes accuracy a whole lot easier. (& is much less time consuming trying to get none dedicated bits & bobs to work in an enviroment they were never intended for)

PS Oh btw I'd imagine that after 6 years, the OP has probably found a solution by now!

[peu]

maybe you can get ideas here: http://machsupport.com/forum/index.php/topic,50.0.html