Methods that I have used for encoding of precision shaft positions have
all been optical based on etchings on a shaft or disk, or gratings on
film. This could be two gratings, 1 being a mask for the other behaving
as a shutter as the shaft is rotated to produce 1 pulse per degree.
Precision laser etched strips or disks are another way to go. I have
used these to encode down into the micron levels. (not cheap though).

It may be possible to make the optical grating/shutter with a cad
package and a laser printer with transparent film in the printer. Try a
strobe bar ratio of 359/360 the 359 disk is fixed, the 360 disk rotates.

Vern

SavanaPics@AOL.COM wrote:
>
> I don't know if this is applicable to you ap, but in the current issue of
> Circuit Celar there is an article on building an orbital tracking system for use
> with  one of two rotors. Object here is that the positioning is done with a
> pot and an A/D converter.  Point being that the signal is accurrate to within
> .028 degrees.
>
> Of coure you will have to either use a 10 turn pot or remove the stop from a
> standard one which will give an area of uncertainty.  This assume the shaft
> only turns one turn and then reverses
>
> Eddie Turner, kc4awz
>
> --
> http://www.piclist.com#nomail Going offline? Don't AutoReply us!
> email listserv@mitvma.mit.edu with SET PICList DIGEST in the body

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listserv@mitvma.mit.edu with SET PICList DIGEST in the body