mechanical computation: with Merkle gates, height fields, and thread

[Dave Long]

Le 28 juin 10 à 09:37, Kragen Javier Sitaker a écrit :

> But braking can provide amplification. Imagine that you have a thread
> running along the surface of a cylinder; it can slide freely, as far
> as it as long as no force presses it against the cylinder. If another
> thread is wrapped loosely several times around the cylinder and the
> sliding thread, the sliding thread can still slide; but if the wrapped
> thread is then pulled taut, it presses the sliding thread against the
> cylinder, preventing it from sliding.


if the cylinder is externally powered, a single thread suffices; when  
it is wrapped loosely no power is coupled, but a little tension on  
the input side produces a lot on the output side.

cf differential analyzers (previous century) and capstans (previous  
millenium) Friction-effect transhawsers?

-Dave

(early automated feedback applications were for windmills; I wouldn't  
be surprised if the separation of power and control had also been  
useful relatively early for animal-driven milling...)