Re: Optical mouse for DRO anyone? - not for WIRE!

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Mark Vaughan" <mark@...> wrote:

>
> I would have thought it would be better to measure it under a known

tension

> where it is consistent.
>
> A set of rollers to keep it taught with measurement in between, or

off of

> one of the rollers.
>

That's a good idea, you could use rollers to transport and tension the
cord and a single gripper on a linear track for measurement between
the rollers. The gripper grabs the cord, the cord pulled by roller
system, the grippers movement is tracked by cheap USdigital linear
encoder or homebrew string encoder. The cord pull is stopped and
gripper returned to start position by some simple means and the
operation repeated.

you could do it very simply using some bog standard DRO software, you
would just need to switch the encoder out of the circuit on its return
trip.

Graham