Scan thru effects?

[DMills]

I am working up a new projector and have been scratching my head about the best way to implement some scan thru effects (gratings, lumia, all that good stuff), and I got to thinking about the rotating gobo wheels used in moving lights.....

These typically consist of a circular plate with 8 or so holes that take glass patterns and that are normally configured with two stepper motors so you can rotate the appropriate pattern into the beam and then use the second motor to cause the pattern to rotate within its mounting.

The firmware will probably be a weekends work to write, and scrap movers are not uncommon.

Sounds perfect to me, but I have not seen anyone do it, is there something basic I am missing?

Just want to make sure I am not going down a blind alley.

Regards, Dan.

[Doc]

Sounds feasible Dan, so long as you can get the gratings cut to fit in the gobo holders.

Ian

[p1t8ull]

Stepper gobos with transmission gratings were used a lot in the good old days, always looked good

[Things]

Lumia effects are typicaly created by rotating the diffraction grating very slowly, and the effects are caused by the laser hitting different points of the grating, not sure how you'd rotate the laser in a gobo wheel, keeping the laser on a different point on the grating, but for everything else it would work.

One main way people do it is use actuators that move a mirror into the beam, diverting it to the various other effects ...

[DMills]

Lumia effects are typicaly created by rotating the diffraction grating very slowly,

Diffraction grating for a lumia effect? I always use shower glass!

One main way people do it is use actuators that move a mirror into the beam, diverting it to the various other effects ...

Yea, fine (GM20s and all that), but not a scan through effect, I am thinking that scaning through a pair of transmission gratings with one slowly rotating might make for some very interesting effects (particularly if done with a multiline gas laser).

Regards, Dan.

[laserist]

A big wheel covers a lot of real estate. Of course that's not very important in systems without multiple scanners or significant lumia capabilities in the first place. The other down side is that you often want to run lumia effects using multiple colors passing through different parts of the effect glass. Using a single scanner requires throwing away your green and blue to do pure red - etc.

[DMills]

Not really, I was going to put the gobo wheel on my main scanners (just after the PCAOM)and use the dump beam from the AOM via a pair of prisms to cancel the dispersion) to run some standard beam table stuff and a second set of scanners via a simple GM20 colour box.

No point in wasting light that you have paid all that money to create after all!

The source is an I90 (with added diode red) so there is about 5 feet down the side of the resonator to mount the beam table stuff.

Regards, Dan.

[Things]

Diffraction grating for a lumia effect? I always use shower glass!


Regards, Dan.

Technically anything that distorts and diffracts the light is a diffraction grating

[DMills]

Picky, picky!
Diffraction, sure, not so certain about the grating bit!

Regards, Dan.

[Doc]

Technically anything that distorts and diffracts the light is a diffraction grating

Grating are just that; effectively many small slits arranged at regular spacings, like a drain grating only a tad closer together