Page 1 of 4 1234 LastLast
Results 1 to 10 of 33

Thread: Beam Director

  1. #1
    Join Date
    Feb 2011
    Location
    New Hampshire
    Posts
    3,513

    Default Beam Director

    I need to steer a large diameter beam (50mm in diameter) with remote (computer controlled) input. The speed is REALLY SLOW. The beam is pulsed at up to a maximum of 4 PPS and the pulse is essentially instantaneous and so nearly 250msec are available for the mirror(s) to slew and settle.

    I originally thought a pair of big mirrors on two of the Pangolin Vrad motors would work, but these mirrors have to be really huge and the controller will also need an amplifier to drive the motors. What about adapting the moving head mount on a Gobo? With the light removed and a single mirror around 150mm square the X and Y can be handled by a single mirror and the control for these already exists as part of their standard operation. How rapidly can these be aimed? Would there be a best choice for my application? If they loose a signal or power do they go nuts or can they remain steady or move to a "safe" mode?

  2. #2
    swamidog's Avatar
    swamidog is online now Jr. Woodchuckington Janitor III, Esq.
    Join Date
    Nov 2006
    Location
    santa fe, nm
    Posts
    1,545,752

    Default

    what about something like this?

    http://www.zaber.com/products/produc...M&tab=Features


    Quote Originally Posted by planters View Post
    I need to steer a large diameter beam (50mm in diameter) with remote (computer controlled) input. The speed is REALLY SLOW. The beam is pulsed at up to a maximum of 4 PPS and the pulse is essentially instantaneous and so nearly 250msec are available for the mirror(s) to slew and settle.

    I originally thought a pair of big mirrors on two of the Pangolin Vrad motors would work, but these mirrors have to be really huge and the controller will also need an amplifier to drive the motors. What about adapting the moving head mount on a Gobo? With the light removed and a single mirror around 150mm square the X and Y can be handled by a single mirror and the control for these already exists as part of their standard operation. How rapidly can these be aimed? Would there be a best choice for my application? If they loose a signal or power do they go nuts or can they remain steady or move to a "safe" mode?
    suppose you're thinkin' about a plate o' shrimp. Suddenly someone'll say, like, plate, or shrimp, or plate o' shrimp out of the blue, no explanation. No point in lookin' for one, either. It's all part of a cosmic unconciousness.

  3. #3
    Join Date
    Feb 2011
    Location
    New Hampshire
    Posts
    3,513

    Default

    I don't think this will do it. If the beam is striking the mirror at a 45 degree angle, the optic will need to be a minimum of 3 inches in diameter and the beam may need to be directed such that the foreshortening will require as much as 5 inches. Also, the extreme resolution implies that the max speed is slow. I am hoping to get say 100 degrees/ second or better between pulses. The range at 20 degrees optical is not too bad.

  4. #4
    Join Date
    Jan 2015
    Location
    Seattle Washington USA
    Posts
    52

    Default

    is this for lab or light show?
    Stepper motors?
    would u b interested in a older big galvo w/ paddle mirror? there is some older stuff like for fiber fed heads for YAG

  5. #5
    Join Date
    Feb 2011
    Location
    New Hampshire
    Posts
    3,513

    Default

    is this for lab or light show?
    Neither, really. I am trying to steer a pulsed laser to track and then target moving objects (inanimate!). I don't know how big the paddle mirrors get, but other than big industrial galvos, I suspect nearly 80mm minor axis would be very rare. The only reason I don't think this project is crazy hard is the very slow speed for repositioning. Stepper motors are a good idea if micro-stepping resolution is available. The precision jitter error of these micro-steps is acceptable. The reason the moving head is interesting me is that the Y mirror in a mirror pair becomes tremendous. For a clear aperture without vignetting the Y has to be at least 3 times as long as the 50mm beam is wide!

  6. #6
    Join Date
    Jan 2015
    Location
    Seattle Washington USA
    Posts
    52

    Default

    a small turret would work too i guess then. or a mirror on a yoke. how accurate r u trying to get? with OpenCV or Openframeworks, an arduino and microstepping drivers you could pull it off affordably.
    https://www.youtube.com/results?search_query=sentry+gun

  7. #7
    Join Date
    Feb 2008
    Location
    Northern Indiana
    Posts
    921

    Default

    have you looked into hobby servos? Very easy to control.

  8. #8
    mixedgas's Avatar
    mixedgas is offline Creaky Old Award Winning Bastard Technologist
    Infinitus Excellentia Ion Laser Dominatus
    Join Date
    May 2007
    Location
    A lab with some dripping water on the floor.
    Posts
    9,890

    Default

    I have some 3" diameter 45' directors on ball bearing bases designed to be turned. I'll take a pic when I get home. I have a LOT of them.

    Steve
    Qui habet Christos, habet Vitam!
    I should have rented the space under my name for advertising.
    When I still could have...

  9. #9
    Join Date
    Feb 2011
    Location
    New Hampshire
    Posts
    3,513

    Default

    I got a neat suggestion from an interesting source.

    http://www.hobbyking.com/hobbyking/s...ontroller.html

    For those with drone experience this might not be the best choice, but in general these gimbals seem to be a really good solution. They slew to 2000 degrees/ second, are made to move weights similar to a good quality (thick) 150mm square mirror and they are inexpensive. They need to interface with a computer and the dongle suggests this one does.

  10. #10
    Join Date
    Dec 2007
    Location
    The West
    Posts
    1,285

    Default

    RGB laser projectors
    Pangolin Beyond .NET
    APC40 Midi controllers
    Pangolin FB3 controllers
    DZ splitter
    LS MegaWatt Green Machine

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •