John De Villiers wrote:
>
> This is the way i aslo assumed things to work but......
>
> My genius netmouse pro had only one pickup on each encoder wheel.

It does not require two complete sensors, one led and transistors
or one transistor and two (modulated) leds


                     led
                      V
     disk ____   ____    ____    ____

           sensors   1  2

--
Peter Cousens
email: p.cousens@cwcom.net  or  p.cousens@virgin.net
smail: 48, Yarmouth Cresent, London, N179PQ, England.


> > Andreas Pockberger wrote:
> >
> > > The trick is that there are two sensors for each wheel so you will get
> > > 2 impulsstreams out of one wheel the phases are 90 degrees shifted
> >
> >                                  |  Reading point
> >                                  V
> >              ___     ___     ___     ___     ___     ___     ___     _
> > Stream A|___|   |___|   |___|   |___|   |___|   |___|   |___|   |___|
> >            ___     ___     ___     ___     ___     ___     ___     ___
> > Stream B__|   |___|   |___|   |___|   |___|   |___|   |___|   |___|
> >
> >
> >