Simple, cheap 3-phase projector

[DeadlyDad]

Tell me how you would change this to work better:

Make a projector out of a light source, lens, loop of clear film with
the phases printed on it, and a stepper motor to rotate the loop. The
stepper motor would advance the film one phase whenever the camera
system was ready to take another frame. The same type of system could
be used for Grey Code projection.

It's a paradox to me; it seems *far* too simple to both work, and not
work.

[Elliot Woods]

I think there was a simple system which used a moving grating to produce vertical sine wave intensity output. Cant remember the link right now

Sent from my phone

[Keith O]

For vertical, you would just have to print the phases on a slight slant, then tip the projector the same amount.  The result would be the lines moving left/right.   ...or just rotate the original setup 90 degrees.

Keith

[Elliot Woods]

Yes, exactly. 

The neat thing was that to produce the intensity waves it was suet simple. Just some metal bars which cast out of focus shadows. The setup I saw didn't have moving bars, but that's definitely possible (although perhaps more difficult to sync at 60Hz).

Sent from my phone

[Keith O]

Neat!  Tilting the bars would actually be pretty simple; take a hamster wheel and twist the hoops in opposite directions.  All of the bars would still be parallel, but no longer perpendicular to the hoops.  (Just an analogy.)

Keith

[Roy Macdonald]

What about grabbing an old photo film projector, make the paterns in a transparency film, add the photo plastic frame and you are ready to go.
If your parents were keen on taking photographs in the 90`s and 80´s they`ll probably have one of these projectors.

--
Roy Macdonald
8-248 8478

[Keith O]

That would work, too, if you had one, though that would be a *lot* slower.  OTOH, if you have a static target and lots of time, you could use a digital camera to get *very* high resolution pics.   Add a rotating platform and half-circle dolly rails to the mix, and you would have a 3D scanner that would be second to none!

Keith