Re: mouse encoder

At 01:12 22/08/2001 +0000, you wrote:

>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.

For a given read head that is indeed true, because the head must have two
sensors spaced 90 degrees out of phase to generate the quadrature signal.
However, the important parameters here are the slot size and their spacing,
not the number of slots per se. Should be possible to make a higher count
disc by using the right slot size & increasing the diameter of the disc
appropriately. So (for example), if the existing disc is 1cm in diameter &
has 50 slots, a 4cm diameter disc will have exactly the right circumference
to accommodate 200 slots of the same size and spacing.

Regards,
Tony