[HomeBrew] Shaft encoder lesson

[Richard Blackman]

Thanks to all who responded so quickly to my question regarding the flavours 
of shaft encoders.

I have determined that it is the 'Grey Code'  type that is required.
I read the "PIC Tutorial"   lectures from John McDonough / WB8RCR, there is 
a chapter on shaft encoders. It is a very good lesson series available for 
download on the web. Ham radio is definitely for learnin' new things.

'Grey Code'
 uses two outputs that allow us to sense whether the shaft is turning and if 
so, in which direction. Each of the two outputs is a square wave dependant 
on shaft position. The two square waves are out of phase, which allows the 
PIC to determine direction of rotation.

An encoder with 'binary output' has higher resolution, but therefore  more 
bits,  and therefore more PIC pins are needed to sense position.

Thanks again to the group and I will let you know more as the project 
continues.
Richard VA3NDO