I'm interested in comments on quad encoder solutions.  For my application, I
have already decided to use HCTL-2000 decoders rather than decoding in
software, because the PIC that will be reading shaft speed will need to read
2 encoders at high speed and will have additional tasks to attend to.

The tricky part is the encoder itself.  I have a 1/4" shaft, spinning at a
maximum of 8000 rpm.  I also want to be able to sample meaningfull results
every 10 mSecs.  With minimum shaft speed around 180 rpm, this requires
around 100 holes (400 state positions) per revolution to ensure that the
10mSec count totals can provide at least 1:10 speed resolution on the low
shaft speeds.

I have considered making my own encoder, but machining an encoder disk with
100 holes is a little tricky.  And I'm guessing that a poorly designed or
constructed encoder would have problems with stray light reaching the
photodiodes at the wrong times.

The only packaged solution I have found that is up to the task is an E5M
from USDigital, at $69 in single quantities.  Are there any cheaper and/or
better encoder solutions that I ought to be looking at?

thanks