Re: [CAD_CAM_EDM_DRO] Laser mouse based DRO

I doubt that this would work very well in our applications.
Laser mice operate by detecting the interference pattern
produced by the laser light shining on an irregular surface.
As the mouse moves the interference pattern moves.
The amount of movement of the pattern relates to the
amount of movement of the surface. The relationship is
not necessarily linear. This is OK for a mouse but
is useless for a CNC or DRO.

For our applications it must be highly repeatable. The
interference pattern is not repeatable in practical use.
The interference pattern is sensitive to movement in
all the X, Y and Y axes. Can you move in the X
axis and have no movement in the Y or Z axis? Remember
if you are off by a fraction of the wavelength of light
in the Y or Z axis you have disturbed the X axis.

There are laser interferometer DRO type devices but
they operate completely differently. They also
cost a lot more.

Pete.

----- Original Message -----
From: "Matthew Glenn Shaver" <mshaver@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Sunday, August 21, 2005 8:09 PM
Subject: Re: [CAD_CAM_EDM_DRO] Laser mouse based DRO


> On Sat, 2005-08-20 at 18:06 -0400, Howard Bailey wrote:
>> This resolution should be plenty adequate for a DRO if the
>> communication to the PC is reliable. Past posts have remarked that
>> the programming could be as simple as a few lines of visual basic to
>> make a mouse based DRO out of an old computer. I was curious if
>> anyone has looked into the new higher resolution mice for this.
>
> Here's a data sheet for the sensors (Agilent):
>
> http://cp.literature.agilent.com/litweb/pdf/5989-3437EN.pdf
>
> Matt