Re: [CAD_CAM_EDM_DRO] Re: mouse encoder?

----- Original Message -----
From: Tim <timg@...>

> You can make all the disks you want, but the encoder read head has to
match the disk to generate quadrature output properly. The people at US
Digital told me that you are OK up to about a 10% variation from the
designed count for a particular head.
>
That's because the mask in the read head has to match the line pitch of the
wheel. The read head actually senses 3-4 lines at once. The mask is a
pattern of lines that match the lines on the wheel. When they line up you
get transmission between the lines. When they are out of phase the light is
blocked.

A disk with milled slots might allow you to get away with passing light
through just one slot but you should still have a mask slot for clean
switching. I guess it depends on what one expects out of the thing.

Doug