[HomeBrew] Shaft encoder lesson

[James Duffer]

The encoders used in some altimeter transponders (replying mode C) are in 
Gray code.  The incremental values only change one bit in the code as they 
increase or decrease in value.  This probably won't help, but might give you 
and idea.  I would thing the decoding logic should determine what kind of 
encoder you will require.

Good luck with your project and let us know the progress you make.

73, Jim de wd4air


>From: "Richard Blackman" <richard.blackman at sympatico.ca>
>To: "HOMEBREW" <homebrew at mailman.qth.net>
>Subject: [HomeBrew] Shaft encoder lesson
>Date: Tue, 28 Mar 2006 17:50:41 -0500
>
>** Please do NOT cross-post messages when posting to HOMEBREW **
>
>Greetings to all on list.
>I am in need of your expertise regarding mechanical shaft encoders.
>I am building a DDS VFO project and it calls for a mechanical encoder with 
>three pins.
>Output A, Com, Output B. so far so good.
>I already own an optical shaft encoder, but I do not know how to adapt it 
>to the circuit.
>
>Question:
>
>When I go to the Digikey site to order  a mechanical "Grayhill"  encoder, I 
>find they come in different flavours, such as hexadecimal, 2 bit, grey, and 
>quadrature. I have no idea what I need.
>
>The encoder will feed a 16F628,    A to  RA0,  B to RA1  and com to RB4
>
>Please-  what is the difference between the encoder types?  Am I asking a 
>question that takes a textbook chapter to answer?
>any comments appreciated
>
>Richard  VA3NDO
>
>_______________________________________________
>HomeBrew mailing list
>HomeBrew at mailman.qth.net
>http://mailman.qth.net/mailman/listinfo/homebrew