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Thread: Back then...this is what we did...

  1. #41
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    Default Diffraction effects

    One effect we had was the "Wendy's box top" effect... Aptly named because it was a piece of precision cut plastic from the window on top of a Wendy's fast food container. 😂

    Frankly it wasn't that great of an effect, but I was also a big fan of Lumia.

  2. #42
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    Default Back then we had to keep it simple from a cost and availability standpoint....

    In my first planetarium laser projector I needed slow rotating diffraction gratings that could be moved in or out of the RYGB galvo beam paths along with 3 types of slow moving laser clouds that could be moved in or out of the RYGB1B2 cloud beam paths. Most items for this were purchased surplus. Edmund Scientific was a prolific source for surplus motors and optics. From Edmund I bought Synchron 110vac motors at $1 apiece, all surplus, a dozen of each speed at .5 rpm, 1 rpm, 2 rpm and 5 rpm along with 50/50 cube and mirror beam splitters. My good friend and planetarium special effects "cludger" extraordinaire knew we would use these for rotating effects, but just how we would do it was not determined yet. When asked how he planned to hold everything together in his latest gizmo his universal answer was "hot glue!".

    In the very early 70's I got into 35mm SLR cameras and their accessories. In the mid 70's I purchased some 55mm "special effects" filters that would spin on my Canon Ftb 50mm SLR lens. They were actually various diffraction gratings but I didn't know that at the time, but when I started building my 1st laser projector they were a godsend.

    My original Synchron motors and acrylic mounts and sliders are long gone, tossed in the trash when having to reduce how much weight we could afford to move from Texas to Colorado in 2013, but I removed all the pins, bushings and grommets and saved them along with the gratings and cloud discs.

    It turned out that the .5 and 1 rpm motors were the only ones we used for both diffraction lens and cloud disc rotating mechanisms. I recently bought two 1 rpm Synchron motors on Ebay for far, far, far, far more than I originally paid, when planning to recreate some of these mounts. Here is what we originally came up with for the 55mm diffraction lens gizmo. The parts and pieces are laid out below.

    These original mounts were made using only a table saw, drill press, a 2" dia. drill press hole saw with one small exception, a small metal lathe. I recreated a dimensional CAD/CAM drawing this past year planning to make some on my CNC machine, but decided that today I would make the first recreation of one using the same method as done originally.


    Click image for larger version. 

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    .25" black acrylic sheets were cut up into rectangles, shown here is a .20" clear acrylic blank and another one drilled and sanded down
    1/8" brass rod cut to small lengths
    1/8" wheel collars (used in model airplane wheels)
    1/8" I.D. x 3/8" brass bushings
    1/8" I.D. brass tubing (used in model airplane fuel lines and shown in later photo)
    3/8" O.D. x 1/4" dia. shoulder x .15" I.D. rubber chassis grommet (shown in later photo)
    2 - 4-40 screws, lock washer and nuts
    1 - .5 or 1rpm Syncrhon motor
    1 - 55mm camera diffraction filter
    1 - large o-ring to surround the diffraction filter housing


    I'd been designing new slow, variable speed "rotators" for use with my RGB LED laser projector and decided to resurrect the past as well.

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    The brass rods, their ends slightly beveled, are press fit into their mounting holes. The brass bushing rotates freely and held in place by the wheel collar. The brass bushing had been chucked in a small metal lathe to carve a small concave recess for the O-ring to roll in. The large hole is 2" in diameter.

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    The motor is mounted with the two 4-40 machine screw hardware. The 1/8" brass tube and rubber grommet are shown in this photo. The brass tube is affixed to the 1/8" dia. motor shaft with a dab of super glue or made to press fit. The rubber grommet is slide on the tube the right distance for the O-ring to engage it for the diffraction lens to sit parallel to the acrylic mounting plate. The next views show the final assembly, excluding the mechanism that slides the lens in and out of the beam(s).

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    Using 110vac motors were not my first choice but circumstances where what they were and finding smooth, geared-down, low speed DC motors were expensive back then. Jerky geared-down DC motors were easy to find but that made them useless for grating and cloud effects. 24vdc relays were used to turn the motors on and off.

    There were two rows of mechanical slides that moved these motorized gratings into and out of the galvo beams, with two motorized gratings per slide. This allowed one or two gratings to be in optical "series" with a given galvo beam and both close enough to the galvo output to allow the galvo pair full 30 deg. deflection.

    Needles to say these were very, very inexpensive to make back then and even now (and using .25 to .20" acrylic is over-kill). The cloud disc motor mount variant to this one was far more simple, just cut off the acrylic plate just above the motor mounting bolts, add a 1/8" to 1/4-20 shaft adapter to the motor and drill a 1/4" hole in a circular Plexiglass cloud disc 3-4 inches in diameter to mount on the shaft adapter.

    My revision of this basic design utilizes very smooth, gear-down .6 rpm, 12v DC motors with motor speed controllers.
    Edit: 4/5/22 corrects some minor errors
    Last edited by lasermaster1977; 04-05-2022 at 17:13.
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  3. #43
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    Default Lumia effects wheels

    Quote Originally Posted by lasermaster1977 View Post
    In my first planetarium laser projector I needed slow rotating diffraction gratings that could be moved in or out of the RYGB galvo beam paths along with 3 types of slow moving laser clouds that could be moved in or out of the RYGB1B2 cloud beam paths.
    Yes, a very challenging design, all things considered, especially if multiple effects need to be moved in and out of the galvo's scan range. My 1st attempt, back in the day looked very similar to your plexiglass/camera lens solution, except I thought I'd be cleaver and use 'revolutionary' thin teflon bearings. Your floating drive band is far better. The Teflon bearing was a total failure.
    Located at the plexiglass' center point of your motor, I had concentric shafts (as you mention at the end) connected to solenoids to rotate each lumia effects arm (your plexiglass) into the scan path (similar to the mechanism for applying colored filters inside a spotlight).
    Once rotated into position, the lumia wheels bottomed out against friction drive wheels (RC tires) But, I've since abandoned that approach in favor of your 3 point contact/countering forces concept.
    In the very early 70's I got into 35mm SLR cameras and their accessories. In the mid 70's I purchased some 55mm "special effects" filters that would spin on my Canon Ftb 50mm SLR lens. They were actually various diffraction gratings but I didn't know that at the time, but when I started building my 1st laser projector they were a godsend.
    Same here. Inexpensive and better than any DIY attempt.
    These original mounts were made using only a table saw, drill press, a 2" dia. drill press hole saw with one small exception, a small metal lathe.
    Except for the lathe (I'd love a minilathe), I call that my machine shop. lol
    I recreated a dimensional CAD/CAM drawing this past year planning to make some on my CNC machine, but decided that today I would make the first recreation of one using the same method as done originally.
    Now, I'm down right jealous.

    I'd been designing new slow, variable speed "rotators" for use with my RGB LED laser projector and decided to resurrect the past as well.
    IMHO, a diff grating and/or cross gratings are the only lumia effects that are worth the mechanical challenge for scanning through, unless your inside a dome, of course. 'Tank' from Laserium I was the only time I did that. Even then, it was mostly beams on a joystick.
    Rotation is also a problem, because diff gratings usually need to kick in at a precise horizontal presets, which would probably require rotating to an start point sensor.
    As you mentioned, keeping all of that within a 2" scan range, with 1/2" already lost in just clearing the X/Y mount is a considerable design challenge.
    Me thinks few pre-oriented diff flags on opposing hobby servo arms are a good compromise. The gratings can still be tilted within a limited range. But, I'm only doing me.
    Most of the other lumia effects need a small beam to produce clear interference cloud effects. So I'm going to use a separate dedicated lumia projector, using static beams from a pair of el cheapo RGB modules.
    My initial thoughts were to build a servo controlled rotating disc, with multiple ports.
    All lumia wheels would be driven from a concentric drive shaft, as you have described below. But, a 'serpentine belt' approach would be needed to counter balance the side forces and float the effects wheels, just as you're doing.
    All of this can be achieved with PWR from 8 spare GPIO pins and an H bridge for the 12VDC drive motor.

    ON THE OTHER HAND: I've, just talked myself out of that approach. It's much easier to redirect static beam paths than repositioning lumia wheels, around a driveshaft. A row of lumia wheels, with individual drive motors (powered from a common signal & amp) would be a far simpler solution to build.

    The 6 RGB LDs from the 2 old projectors will be repurposed and configured into pairs of RG,GB,RB to create 3 separate beams, individually tunable within 3 color bandwidths. Their 3 beams will be positioned 120 degrees apart around the center of the currently selected lumia wheel. This will create 3 overlaid clouds, of different colors, moving in 3 different directions at the desired speed. (same cloud formations, swirling around the projection surface in crossfading colors... or not from another lumia port, with differently arranged pickoff mirrors. ;-)
    This approach allows me to have the best of background lumia clouds, while retaining the ability to have a sharp cycloid dancing in the foreground and using specialized projectors to fade between and both being controlled from the same MCU.
    Lumia in front of scanners eliminates that ability, without multiple projectors.
    I'm still using multiple projectors, but without the costs of the second pair of galvos, which also require supporting signals, amps, etc.

    Hey Folks! Here's a blast from the past for scanning through optical devices.
    Hang the scanning head in the middle of the room, scanning straight down. Mount a 2" 45 degree reflect telescope mirror that redirects the image 90 degrees. That, alone can allow projecting onto a surface (mind the optically induced image rotation).
    Then, queue the fog and spin that sucker @ ~ 1500 RPM to create a 360 degree ceiling, similar to a cone motor except it's a laser ceiling.
    Apply blanking and/or colormod for harmonic spinning spokes. Now, joystick the beam to tilt the ceiling around the center point.
    Bring on a QOSC to produce 360 deg waves around the room. If you can spin your text, then you can have a banner.
    If you can spin your wireframe graphics at the ceiling's same rotation rate, then apply a reverse sawtooth to the horizontal motion, then you can have multiple images around the perimeter of the room.

    Looking forward to seeing your final lumia assembly, Lasermaster1977. No doubt, your up to stuff that I haven't even imagined.
    BR
    Last edited by TheHermit; 07-16-2022 at 12:10.

  4. #44
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    Default

    Quote Originally Posted by TheHermit View Post
    Yes, a very challenging design, all things considered, especially if multiple effects need to be moved in and out of the galvo's scan range. My 1st attempt, back in the day looked very similar to your plexiglass/camera lens solution, except I thought I'd be cleaver and use 'revolutionary' thin teflon bearings. Your floating drive band is far better. The Teflon bearing was a total failure.
    Located at the plexiglass' center point of your motor, I had concentric shafts (as you mention at the end) connected to solenoids to rotate each lumia effects arm (your plexiglass) into the scan path (similar to the mechanism for applying colored filters inside a spotlight).
    Once rotated into position, the lumia wheels bottomed out against friction drive wheels (RC tires) But, I've since abandoned that approach in favor of your 3 point contact/countering forces concept.

    IMHO, a diff grating and/or cross gratings are the only lumia effects that are worth the mechanical challenge for scanning through, unless your inside a dome, of course. 'Tank' from Laserium I was the only time I did that. Even then, it was mostly beams on a joystick.
    Rotation is also a problem, because diff gratings usually need to kick in at a precise horizontal presets, which would probably require rotating to an start point sensor.
    Somewhere in my posts there is a description of the planetarium director's assistant "techie" and my first attempt using re-purposed leadscrews to move the effect wheel in/out of the beam. Each one was so loud and sounded similar to a slightly muted garbage disposal.

    We replaced that horrible conglomerate with these mounts, this mount was attached to a Teflon block slide mount that slid on parallel 1/4" horizontal rods and could move into the scan pair paths or the dedicated lumia beam path(s). The "motion controller" was my long time assistant laserist who "pulled strings" to move the Teflon slide block back and forth. He also turned the beam flags effect wheel motors on/off. I never bothered with indexing the diffraction gratings to a home position because we could use one diffraction grating or one shooting through a 2nd grating. The randomness of what actually happened turned out to assure something different and unique happened everytime.

    Except for the lathe (I'd love a minilathe), I call that my machine shop. lol
    It wasn't my lathe


    So I'm going to use a separate dedicated lumia projector, using static beams from a pair of el cheapo RGB modules. It's much easier to redirect static beam paths than repositioning lumia wheels, around a driveshaft.
    That's always been my preference, too, static beams that can be switched to different beam paths.

    Looking forward to seeing your final lumia assembly, Lasermaster1977. No doubt, your up to stuff that I haven't even imagined.
    BR
    Yeah, but I need more RGB LDs and they seem so hard to find that are good quality and power at a reasonable price these days. I can't wait to reveal one of my first "laser cloud" effects from my early days, that I've not seen anyone else do.
    ________________________________
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  5. #45
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    Default

    Quote Originally Posted by lasermaster1977 View Post
    Somewhere in my posts there is a description of the planetarium director's assistant "techie" and my first attempt using re-purposed leadscrews to move the effect wheel in/out of the beam. Each one was so loud and sounded similar to a slightly muted garbage disposal.
    lol! The rotary solenoids on my 1st projection head resonated through their aluminum mounts and into the optical rail. They were so loud that in the middle of my 1st trade show, the show director told me to stop the clicking noise. But, pulsing the beam shutter was the only way I could avoid boiling away the glycerol optical fluid (aka 'fiber juice' to protect our IP) inside the glass tube, which matched the refractive index as the quartz lens on the front and the fiber, being held in alignment with a collet (ala mechanical pencil). Fortunately, my trusty assistant was right thereinform me of the problem over our cans.
    "Keep adding fiber juice." I said.
    "Quiet on cans, please!"
    He was able to keep the level topped up with a syringe and take over the beam pulsing with the laser head's attenuator. lol!

    We replaced that horrible conglomerate with these mounts, this mount was attached to a Teflon block slide mount that slid on parallel 1/4" horizontal rods and could move into the scan pair paths or the dedicated lumia beam path(s). The "motion controller" was my long time assistant laserist who "pulled strings" to move the Teflon slide block back and forth. He also turned the beam flags effect wheel motors on/off. I never bothered with indexing the diffraction gratings to a home position because we could use one diffraction grating or one shooting through a 2nd grating. The randomness of what actually happened turned out to assure something different and unique happened everytime.
    The band Yes once had a 5 watt argon, mounted inside a vertical cage with a horizontal 'effects' rack that translated from side to side, which positioned the desired effect 'module' in front of the beam. /smh

    Yeah, but I need more RGB LDs and they seem so hard to find that are good quality and power at a reasonable price these days. I can't wait to reveal one of my first "laser cloud" effects from my early days, that I've not seen anyone else do.
    Seems to be an all too common theme, these days, eh?
    Last edited by TheHermit; 07-16-2022 at 15:25.

  6. #46
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    Default Thanks - Great Thread!

    Thanks for the great detail on this!

    It’s always good to know where much of the early tech came from. The mention of “LoveLight” certainly brings back early memories (I never saw it, but had read of it).

    Greg
    "Information not shared, is information lost forever"

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  7. #47
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    Quote Originally Posted by Displaser View Post
    Thanks for the great detail on this!

    It’s always good to know where much of the early tech came from. The mention of “LoveLight” certainly brings back early memories (I never saw it, but had read of it).

    Greg
    LoveLight was very unentertaining but served to prove a point by General Scanning's prime contributor of torsion bar XY galvos...that they could "draw" fast animations. Viewing line drawing vector graphic animations of moving animals etc. was interesting, but just barely for me and others. To wit: It didn't have a very long life at the Metropole Theater, anyway.

    Abstract harmonographics (aka cycloids) is what has always pulled in the audiences, because the audiences explored their imaginations while watching them, and lumia, was why it was e-n-t-e-r-t-a-i-n-i-n-g.

    TheHermit and I just had a discussion about this.
    Last edited by lasermaster1977; 07-18-2022 at 19:23.
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  8. #48
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    Default

    Quote Originally Posted by lasermaster1977 View Post
    LoveLight was very unentertaining but served to prove a point by General Scanning's prime contributor of torsion bar XY galvos...that they could "draw" fast animations. Viewing line drawing vector graphic animations of moving animals etc. was interesting, but just barely for me and others. To wit: It didn't have a very long life at the Metropol Theater, anyway.

    Abstract harmonographics (aka cycloids) is what has always pulled in the audiences, because the audiences explored their imaginations while watching them, and lumia, was why it was e-n-t-e-r-t-a-i-n-i-n-g.

    TheHermit and I just had a discussion about this.
    "WOW!! Look that, Honey! I've never seen anything like that before! How do they do that? Look at how it dances and changes with the music! I can't wait to see what it's going to turn into next! We should invite Bob and Alice to see this next weekend. They'd love it!"
    "Yeah, this is really cool, Sweetheart. Phone 'em up. We should get really baked and do this every weekend."
    vs
    "Isn't that line drawing of Bart funny?"
    "Meh, yeah. It's a computerized line drawing, Sweetheart. Let's go watch Star Wars in 3D."
    That's what I witnessed.

    JS
    Last edited by TheHermit; 07-19-2022 at 18:53.
    What goes around, comes around. You are in control of both. People reflect what we project.

  9. #49
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    Quote Originally Posted by lasermaster1977 View Post
    LoveLight was very unentertaining but served to prove a point by General Scanning's prime contributor of torsion bar XY galvos...that they could "draw" fast animations. Viewing line drawing vector graphic animations of moving animals etc. was interesting, but just barely for me and others. To wit: It didn't have a very long life at the Metropol Theater, anyway.
    You just triggered a memory of 'taught band' scanners during that same era. Tiny mirrors attached to a strand of metal, each inside an 1/8" tube. Both tubes were vertically mounted inside a magnetic block. A lens focused the beam onto the 1st mirror, then the image was rotated with a prism, before being refocused onto the second mirror. Very fast and accurate scanning.
    Neil Irwin was Holoco's electronics guru, who developed the imaging computer. We used it with a HeNe on a camera tripod to project the Bond figure, the pistol, and an octopus up and down Tia Carrera's naked body for the title sequence of Octopussy.
    Does anyone on the States' side of the pond remember seeing galvo bocks like those?
    Abstract harmonographics (aka cycloids)
    Visual music is very appropriate too, me thinks.
    What goes around, comes around. You are in control of both. People reflect what we project.

  10. #50
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    Quote Originally Posted by Jem View Post
    What an amazing thread.

    I absolutely love reading the history and innovation of you true pioneers of laser art. I first saw a "Laserium*' show at the London Planetarium back in the seventies. That sowed the seeds of a lifelong fascination with 'the light'. Please keep it coming, every small detail is worthwhile, don't miss anything out.

    Cheers

    Jem

    * Not sure the show was a genuine Laserium show, can anyone confirm?
    David Cooper and I opened Laserium I at the London Planetarium in the summer of 1978. Yes, we were both genuine laserists, working for Laser Images Inc.
    About a year later, we started running Laser Rock II.
    Dave and I alternated every other show night, 3 shows per night. So it was a 50/50 chance that you saw one of my shows. So, on behalf of both of us, thank you and we're very pleased to hear that you enjoyed the show.
    Dave and I went freelance in 1980 and were replaced by a few rounds of laserists, before the planetarium started producing their own laser shows with a system from a laser company from Wales, Laser Systems Ltd., if I remember correctly.
    BR
    😎
    What goes around, comes around. You are in control of both. People reflect what we project.

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