I've often wondered about this myself. If you say that the receiver has 3
pins, it could just be that they have 2 photo-diodes in one receiver packag=
e
and simply see which gets ir light first.

Jason

-----Original Message-----
From: Jan-erik Soderholm (QAC)
[mailto:Jan-erik.Soderholm@PAC.ERICSSON.SE]
Sent: Tuesday, April 29, 2003 11:50
To: PICLIST@MITVMA.MIT.EDU
Subject: [EE]: PC mouse optical detectors.


Hi.
I just scraped an old mouse (a Logitech wheel mouse)
to see what optical components they used.
I noticed that the wheel had one LED (IR?) and one
3 pin "receiver" mounted. Now, the wheel just have a row
of spokes, but someway, the unit must not only detect
spoke/nospoke, but also the direction the wheel is turning.
Anyone know how these receivers work ?

Maybe I'll de-solder a pair and setup a testbed...

No marking on the components, of course...

Jan-Erik.

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