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Thread: Laser System Specs

  1. #1
    Join Date
    Sep 2018
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    Default Laser System Specs

    *Edit: This thread was pretty informative: https://photonlexicon.com/forums/sho...-or-Lightspace

    I'm currently searching for an entry level pre-made system to buy.

    My intention:
    I currently do live performance with oscilloscope, going through a camera to a projector.
    I'd like to get a better image so I'm turning to lasers.
    Planning to either get an ILDA interface or as someone suggested, solder jacks onto the board for modular synth input.
    I should note, I don't need control software since it'll be used strictly for direct input.

    My budget: $1K-$1.4K

    I'm located in Thailand so I suppose importing will be easiest from China.

    I've done a fair bit of reading, and see that there's tons to learn.
    I've seen various recommendations of galvos, lasers, and mirrors on this forum. Brands of pre-made systems are a bit more elusive.
    From what I've read, Kvant is a great brand, but it's a little outside my budget for their entry level stuff.

    I came across these systems from Goldenstar Laser that seem like great value for the money if they live up to their specs.
    Goldenstar D-RGB3000-A
    http://goldenstarlaser.com/index.php?route=product/product&path=81_85&product_id=285
    Goldenstar P-RGB3000
    http://goldenstarlaser.com/index.php?route=product/product&path=81&product_id=475
    I've emailed them to try to find out exactly what model the galvos and lasers are.

    Then there's Laser World:
    Laserworld DS-1000RGB
    https://www.laserworld.com/shop/laserworld-lasers/diode-series/laserworld-ds-1000rgb-show-laser-light
    Laserworld PRO-800RGB
    https://www.laserworld.com/shop/lase...rld-pro-800rgb
    Based in Switzerland so might be a little more expensive to import.

    Another one here, but the website looks a bit dodgy. Sent them an email asking details anyhow.
    Laser King LK-RGB2W
    http://www.laserking.com.hk/products_show.asp?proid=415


    If anyone has advice or recommendations please let me know.

    Cheers!
    Last edited by palinopsic; 09-04-2018 at 03:13.

  2. #2
    Join Date
    Oct 2012
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    Durban South Africa
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    Default

    I own a Laserking LK-D3 this is he second one I have owned without any problems. Ok its not analogue modulation and the scanners are not good for serious graphics but the 8 diffraction gratings work well giving great aerial effects.

  3. #3
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    Quote Originally Posted by BruceLavender View Post
    I own a Laserking LK-D3 this is he second one I have owned without any problems. Ok its not analogue modulation and the scanners are not good for serious graphics but the 8 diffraction gratings work well giving great aerial effects.
    Oscilloscope type graphics can get pretty complex so this might not be the model for me. Good to know Laserking has been solid for you though! I'm waiting to hear back from them about their RGB2W model.

    Thanks for the response Bruce!

  4. #4
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    Default

    Last edited by palinopsic; 09-04-2018 at 03:11.

  5. #5
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    Exclamation A laser projector may not be fast enough for your needs

    You mentioned that currently you're using an oscilloscope for your primary output device. Then you point a camera at it to capture the image before displaying it with a bright video projector, right?

    In this setup you really don't have anything to limit the complexity of the image (well, within reason), since the oscilloscope can easily handle signals in the MHz range and the camera/video projector combo is going to sample the *entire* image 30 or 60 times per second no matter how complex it is. So no problem.

    But while your oscilloscope is steering a beam of electrons (using powerful electromagnets) to draw your image on a phosphor screen, a laser projector uses moving mirrors to draw the image by physically scanning the laser "dot" around on the wall. Those mirrors have significant mass (especially compared to a beam of electrons). The mirror mass limits the speed at which you can move them back and fourth, and this limit is probably a lot lower than you'd imagine.

    For a 30K scanner set, your maximum bandwidth for a small step (call it 3 degrees of scan angle) is just 2500 Hz! And even at that relatively low frequency, you're going to have roughly 3 dB distortion on the position.

    So before you purchase a laser projector, you need to be certain that the signals you are working with are at or below this maximum frequency. Otherwise you won't be able to display them properly using a laser projector.

    Note that there are high-performance scanners available that can increase this frequency limit by as much as 3 times, but those scanners cost several thousand dollars all by themselves and are usually only available in higher-end projectors.

    Adam

  6. #6
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    Quote Originally Posted by buffo View Post
    For a 30K scanner set, your maximum bandwidth for a small step (call it 3 degrees of scan angle) is just 2500 Hz! And even at that relatively low frequency, you're going to have roughly 3 dB distortion on the position.

    So before you purchase a laser projector, you need to be certain that the signals you are working with are at or below this maximum frequency. Otherwise you won't be able to display them properly using a laser projector.
    Great point, maybe I would be better off investing in a 4K digital projector. But then again, lasersss!!!
    I will definitely take time to consider.

    A sales rep for Kvant just told me the ClubMAX 2000 is on sale for $2k USD with pelican case. That's more than I planned to spend, but their reputation is so highly spoken of. It does 40K at 8 degrees, but yeah, like you said...
    If I wanted more bandwidth, the Saturn 1 upgrade would cost more than the system itself.

  7. #7
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    Cool

    Quote Originally Posted by palinopsic View Post
    A sales rep for Kvant just told me the ClubMAX 2000 is on sale for $2k USD with pelican case. That's more than I planned to spend, but their reputation is so highly spoken of. It does 40K at 8 degrees
    So to put that in perspective, those scanners only bump your small signal bandwidth (again, about 3 degrees optical) to a maximum of 3333 Hz. And that's still with the 3dB distortion...

    Basically, take the advertised scan speed of a set of scanners (at 8 degrees) and divide it by 12. That will yield the maximum small-step (~ 3 degrees) bandwidth with 3dB of distortion.

    As for *why* this is true, it has to do with the ILDA test pattern that is used to tune the scanners. The center circle is supposed to just touch the sides of the center square. But if you look at the pattern with an editor, you'll see that the points that make up that circle are actually positioned well outside the center square. The difference between the position of the points in the editor and the location of the circle as it is scanned is your 3dB distortion.

    The scanners are ballistic when scanning the center circle. That is, they are under constant, maximum acceleration throughout the 3 trips they make around the circle. The scanners never even get close to one point before they head off to the next one.

    Thus, one "trip" around the circle is one cycle, or Hz. And there are 12 points that make up the circle. So divide your point speed by those 12 points, and you get the maximum frequency to draw that circle, which makes up about 3 degrees of the 8 degrees total that the pattern displays at. And don't forget that even at this speed the resulting image is already pretty distorted. (If it were perfect, you'd see a 12-sided polygon that was completely outside the center square.)

    So, yeah... Scanners are not high-bandwidth devices. (At least not when compared to an oscilloscope.) We get excited about small improvements in scanner speed, but we have a long way to go before we can compete with the CRT in a 'scope.

    If you're regularly using frequencies above 3 KHz, I suggest you invest in a better video projector instead. It will be cheaper and the output will look much better.

    Now, if your abstracts are running below 2KHz, then displaying them on a laser projector would look *great*. (The Z5 analog console is a perfect example.)

    Adam

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