Scan Through Effects - Any Ideas?

[Displaser]

I'm interested in creating a few scan through effects for my rgb projector planned - diffraction grating, fuzz, etc.

I've considered using r/c servos to swing gearmotor(s) in front of the scanners, as this seems to be a good start. Anyone out there that has incorporated any scan through effects? If so, how are you doing this?

Greg

[Vega]

Hi greg,

I've seen a grid grating put out of a xy galvo head.The grating split the draw tousand times so the final effect is a very caotic "burst" of smaller beam, moving as the original scanned draw. The effect is enhanced if laser is multicolor, cause different wavalenght are splitted again as a prism.
Cheap and impressive, but i don't like so much, so caotic. I prefere static beams.

Andrew

[Stuka]

Hey, Greg -

I'm also thinking about some similar effects for my RGB projector, also still in the planning stages!

I currently have one of these on order:
http://www.laservisuals.com/poly20kit.htm

Unfortunately, not cheap!!

I've also been thinking about adding a "lumia" wheel - search for that subject here and you'll probably get better info from some folks that have been doing this a while (unlike me, who's just been thinking and buying but not done anything yet!! I'm kind of otherwise occupied overseas right now!!)

I also thought about the R/C servo arrangement to flip various gratings, glass, etc. in front of the beam path. It would definitely work, but during performances you'll need to plan on the transition time it takes the motor to move your effect into place, as well as some possibly inadvertent scattered beams as the edge of the effect first enters the beam path.

If you decide to go the servo route and want to automate your projector, I've seen circuit board kits that allow you to control multiple servos through either DMX or MIDI - lots of possibilities!

[QUAZAR]

Use a GM20 actuator. Very fast, almost instantaneous works very well.
Its what I always used.

[mixedgas]

There is the toffee tube or tortured tube lumia
Its a L. Michael Roberts (no relation) invention
take a 6 mm to 9 mm glass tube and put a small twist in
it (easily done with soft flame from propane torch)
scan laser beam through twist while rotating tube avout its long axis
using slow motor. Effect is a slow waterwave thing.

Tortured tube, take a 6 mm to 9 mm or larger pyrex tube, softly melt
spots on it and indent them with a nail or other obect that can take the heat.
If glass sticks to your object, go the other way and pull "inverse" dimples.
makes a real cool effect rotated about its long axis on a small motor.

these are both mentioned in LMRs book on how to do laser shows and are NOt my origional ideas.

Steve Roberts

[carmangary]

You can make a decent lumia wheel by taking one of those clear discs that come with packs of CD blanks and heating it up with a blow torch. When it gets hot enough it will slightly melt and make bubbles in it. Once you have bubbles all over it you can mount it to a motor and it makes nice effects. It took me a couple times with the CD discs before I got one that wasn't too melted and deformed, though. But it definitely is a cheap way for some nice lumia effects.

[dave321]

You can make a decent lumia wheel by taking one of those clear discs that come with packs of CD blanks and heating it up with a blow torch. When it gets hot enough it will slightly melt and make bubbles in it. Once you have bubbles all over it you can mount it to a motor and it makes nice effects. It took me a couple times with the CD discs before I got one that wasn't too melted and deformed, though. But it definitely is a cheap way for some nice lumia effects.

small dots of polystyrene cement on a cd disc also work well...you can build up several layers allowing drying in between.........other clear drying glues may also work. i think the key to good effects is also aided by a motor rotating at less than 1rpm, i think high speeds ruin the effect

[Displaser]

Steve,

I count myself lucky to have a copy of LMR's Laser F/X Handbook, as I'm familiar with the effect you describe from the book, but have not tried this yet. I'll have to add this to the list...

All,

What I'd like to do is spin the DG or other effect in front of the scanners, such as the scan-through std described in ILDA, but don't have the tools/machinist skills to fabricate a turret to do this right. The R/C servo & gearmotor method is my poor boy approach to getting close to this.

I've also found a rippled clear glass sheet at Hobby Lobby, that produces a great lumia effect. I'll dig up the SKU on this, if anybody wants it.

Greg

[Stuka]

I vote yes on posting the info on the rippled glass from Hobby Lobby!
(I'm assuming you're referring to the arts & crafts chain, not the R/C aircraft company in Brentwood, TN!!)

BTW -

I'm going to be using a 1 RPM AC motor for my lumia, controlled by a DMX-activated relay. I just needed a good source for a wheel - and found great ideas here! I think as long as it works, how you did it and the money spent isn't important - it's more about the smiles you get when the lights go out and lasers come on!

[mixedgas]

[QUOTE=Displaser;30694]Steve,

I count myself lucky to have a copy of LMR's Laser F/X Handbook, as I'm familiar with the effect you describe from the book, but have not tried this yet. I'll have to add this to the list...

All,

What I'd like to do is spin the DG or other effect in front of the scanners, such as the scan-through std described in ILDA, but don't have the tools/machinist skills to fabricate a turret to do this right. The R/C servo & gearmotor method is my poor boy approach to getting close to this.

tear down the cheaper RC servos (I know most futabas work for this) remove the sensor potentiometer and remove the rotation limiting pin, gut out the electronics and solder power leads direct to the motor, put back together , run off 1V from a few D cells in parallel instead of 4.8, instant lumia motor, till you go to a junk yard and find the 1 rmp motor out of a old washing machine timer, or a old westclox clock with the 1 rmp motor. 1 rpm ac gearmotors are out there cheap some place. If not theres mcmaster-carr and grainger, probably around 18 bucks though.

Steve