Re: Make your own linear scales

Thanks "Ballendo" (<chuckle>... I think aliases are kind
of funny):

I've often thought that the Spheresyn approach was quite
elegant in its simplicity and ease of manufacture. I've
always guessed (but never researched) that getting
precision sized ball bearings would be fairly
economonical and easy. The only thing I've had as a
problem is how to make the sin/cos reader head. Using
LEDs to create an encoder is very simple (in fact, I was
planning on making a pulse encoder until I found that I
could buy one for $130.... still might do it for fun
though). The same concepts apply but now must be
transferred to analog signals. I believe Hiedenhain
(probably spelled wrong) use this approach. I've never
done a search for chips for sin/cos type encoders...
have you? If you know of any, please let me/us know.
Clearly the electronics begin to dictate the resolution
of the scale (assuming hypothetically perfect balls)
versus the layout of the lines on a disk

--Alan

>Jon,
>
>What is your "gut" feeling about a homeshop guy or gal
>creating glass scales like this? Could we do the
>etching necessary?
>
>What other options do we have for creating our own
>linear scales? (Besides cable/encoder)
>
>I've always thought the "spherosyn" could be "home-shop-
>able" precision ball bearings in a tube, read
>capacitively sin/cos)
>
>Also have thought about the old "wire" tape
>recorders... What about recording a sine wave (signal
>generator created), and reading it with a std. recorder
> head. Then looking for a way to have TRUE metal tape.
>Iron oxide?
>
>Thank you in advance.
>
>Ballendo