RE: [CAD_CAM_EDM_DRO] Re: Optical mouse for DRO anyone? - not for WIRE!

If I might comment.. It would seem that moving a soft, pliable cord through
any measure device would require a force of some sort against some
resistance but you might be able to estimate the change in thickness well
enough to measure with some sort of accuracy.



If you have two rollers of known diameters, with nothing between them, the
space from center to center would be half the diameters added together.
With anything between them, the distance would grow by the compressed
material thickness. If you were to use half of the distance increase in the
distance calculations, the actual distance would seem to be more accurate.



By arranging the mouse such that the �X� axis is the length measurement
axis, you could use the �Y� axis as the measurement axis for the change in
center distance. If the �Y� axis is polled once every �X� axis roller rev
and the calculation adjusted till the next roller rev, it would compensate
for the differences in compression along the length.



R. Wink



On 4/22/07, mrclicit <HYPERLINK
"mailto:chris%40clicsys.com"chris@clicsys.-com> wrote:

>
> Now I don't feel so bad - you are all (well, almost all) missing what
> I said about the medium, and coming up with the same ideas my
> co-workers offered...now.-..
>
> Imagine a shoelace, 100 ft long. Wire and flat strapping or webbing is
> child's play in comparison - been there, done all that 25 years ago.
> Woven cordage changes dimensionally when even the slightest mechanical
> pull, push or squeeze is applied. I have put various types of lacing
> (polyester, nylon, natural fiber, etc.) through wire measurement
> machines with all types of wheels of varying hardness, and they all
> performed horribly, losing or gaining as much as 10 inches in ten
> feet. The company that makes most of these machines even put together
> a custom unit for me that they swore would work, and it did no better.
>
> In theory, the optical mouse should be very accurate if used on a
> surface that has consistent chracteristics. On a Windoze PC, it would
> be difficult, since the pointer calls to the API do not seem to allow
> the low level of control one would expect - as I recall, the
> acceleration algorithm is tied to the travel distance in the available
> API function. Without being able to compile machine code, acceleration
> would be included with distance, hence raw distance throuh a PC would
> be an extremely difficult task.
>
> Reading the raw mouse output it seems, would be much easier to do with
> a PIC and a simple routine to read asynchronous serial. the velocity
> of mouse movement establishes the serial clock, and as long as the
> chip is clocked fast enough, distance should be a no-brainer. The
> problem I see with this approach is the storage and handling of so
> many variables - even if looped every inch.
>
> Time permitting, I'll put something together to try this.

No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.5.463 / Virus Database: 269.5.7/771 - Release Date: 2007/04/21
11:56 AM



No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.5.463 / Virus Database: 269.5.7/771 - Release Date: 2007/04/21
11:56 AM



[Non-text portions of this message have been removed]