Gerhard Fiedler wrote: > Something like routing them all through some springs or so hanging from > the ceiling. The tricky thing here is that the force these "springs" apply > to the cables has to be constant (that is, independent of the extension of > the "spring"), and should be adjustable. I'm not sure such a thing exists. Sure, they're quite common. Just Google for "constant force spring". The most common form is a steel tape, somewhat like a metal tape measure. In fact, you may find that the cheap little pocket tape measures from your local hardware store will meet your needs just fine. They aren't typically "adjustable", however. But then, ordinary springs with adjustable spring constants are rather rare, too. But perhaps you could add an adjustable amount of drag to the mechanism to compensate. -- Dave Tweed -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist