> This is not for a PC application. It will be driving a PIC. I'm looking
> at reading it like a quadrature encoder (I've already used the uart on
> the PIC). It's to be a production unit, so I'd like to avoid having mouse
> guts in it...

But you could recycle the parts ? Although I note you say it's a
production unit. Have you approached a mouse manufacturer
for parts ?

If you break it down - slotted or holed wheel and two pairs of IR
Rx / Tx semis (+ microswitch to select). The semis and switch are
easy to get, so that leaves you with the wheel to find. Perhaps a
plastics manufacturer you can call on has something suitable. They
keep a sample of everything they make. Another possiblity is to
use not transmitted light, but reflected. A plain solid wheel with
alternate white (or shiny) / black stripes. I make speed detection
unit in the range 200 - 250Hz with 1mm stripes and that works
fine. Only 1 pair of small sweet-spot Tx / Rx (ex-mouse as it
happens) semis so it's not set up for direction but it easily could be

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