Homebrew PCBs

mikegw20 wrote:
> Has anyone used an optical mouse for postion sensing?

Your term of "optical mouse" is a bit confusing here.
If you are referring to a ball-driven mechanical mouse
with x/y photo interrupters, yes that is a possible
solution with a few constraints.

The interrupter wheel segments mark off 10* or
36 divisions per revolution for run of the mill
units.  To achieve a resolution in the ballpark
of 0.001" a lead screw having a pitch of 24-28TPI
is required.  This will likely be a conventional
60* cut screw thread rather than a more durable
acme thread which has a broader profile and is
not normally available in this fine of a pitch.

Fabricating a higher resolution photo interrupter
disk is possible via laser printing to transparency
film.  Other sources of quick and dirty photo
interrupters are reclaimed high tooth count gears
from electro-mechanical devices.

A PC mouse is a good starting point in any case
as it furnishes two dual-channel IR quadrature
detectors and emitters which provide a means to
sense rotational displacement as well as direction.

-- 
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