Don Foreman wrote:

On Fri, 03 Feb 2006 18:03:02 GMT, "Ivan Vegvary"
wrote:



"Don Foreman" wrote in message

A friend and I were just discussing ways to know the orientation of a
telescope's equatorial mount. One guy wants to get 12" to 15" brass
gears made and use rotary encoders. That'd work, but I was thinking
that it could also be done electro-optically with a pattern on a disc
or strip.

Don, generate your Acad dwg, or I could do same. Be more than happy to plot
it for you.

Ivan


Cool. I'll see if the guy responds. If he does, I'd be glad to send
you a mailing tube with stamps on it. Just peel off the outer address
label.


As a word of advice onthe encoding, look up "Gray code" techniques.
the reason it's important is that in Gray code, only one bit changes at
any transition. That makes reading the position a lot less prone
to reading errors.

Just a thought...

Richard