So, now I'v had my scope connected to the "third" pin of
the sensor.

In the Idle state (wheel standing still) it outputs
two "1" pulses, 2.5 us and 3.5 us long and with a
15.5 us delay between them. This is repeated each
190 us (or with 5.3 kHz).
It doesn't matter if there is a spoke or not in between.

When the spokes moves in one direction, the second (3.5 us)
pulse becomes longer (aprox 13-14 us) and delay between
the pulses shorter with the same amount so the total
time for both pulses stays the same (21.5 us).

When the spokes moves in the other direction, I had problem
with the triggering of the scope, but it looked like the
first puls gets longer instead, so that most of the
170 us delay becomes a long pulse (part of the "first" pulse).

Anyway, one would realy need a data sheet on these, I suspect.

While soldering tiny "probes" on the PCB, I happend to
burn the sensor for the "wheel". I tried to replace it
with one of the sensors for the "movement" detector, but
obviously they are a little different. They detect movement
(spokes moving by) in two different directions (of by 90 deg).

There are a picture of this actual mouse on this page :
http://www.saitosite.com/pc/0007/pachimouse.html.
Let the page load and search for "SAT48a". There are
two pictures (the page is in Japanes, I think...).


Now, how do one find any datasheet on these ?

Thanks for your time !
Jan-Erik.

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