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DIY Laser graphics? — Parallax Forums

DIY Laser graphics?

FlyingFishFingerFlyingFishFinger Posts: 461
edited 2009-01-22 00:40 in General Discussion
Hi-
As a sort of side project, one of my professors is thinking about creating a laser-based display of live seismic activity on the outside wall of a new building on campus.
The idea is basically a giant oscilloscope where the input is driven by some sort of seismometer. Now, we were looking into various methods of projecting laser images. We think we can do slow ones (where the dot moves visibly without a tail) using some servos. However, then one couldn't really see the waveform. My professor said he was quoted $25000 for a real laser projection system, which agrees with my research on the subject.
Is there a simpler, cheaper way (say, glow-in-the-dark paint or something) that can create the tail effect, or even a proper waveform, using (preferably) a blue laser?
Thanks

Rafael

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
You've got to play the game.
You can't win.
You can't break even, except on a very cold day.
It doesn't get that cold.
~Laws of Thermodynamics~

Comments

  • VelocitVelocit Posts: 119
    edited 2009-01-21 05:30
    Could you use a projector to simulate an oscilloscope trace? When you mentioned projecting something on the side of a building, I immediately thought of this:

    blog.makezine.com/archive/2008/01/learn_how_to_do_laser_gra.html

    It could be a lot less than a "laser projection" system depending on how expensive of a projector the project would require.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    -Paul
  • FlyingFishFingerFlyingFishFinger Posts: 461
    edited 2009-01-21 05:54
    We think an entire projector would be overkill. Also, my professor would like it to be visible during the day as well. I should mention too that the wall we are going to use is brown...

    Rafael

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    You've got to play the game.
    You can't win.
    You can't break even, except on a very cold day.
    It doesn't get that cold.
    ~Laws of Thermodynamics~
  • SRLMSRLM Posts: 5,045
    edited 2009-01-21 06:03
    How about 'emulating' a projector. You can use rotating mirrors and a stationary laser module to move the dot along the wall very fast, and rely on POV to create a line. You'd need two mirrors: one for each axis. Mount the mirrors on some high speed stepper motors and you've got a projection system. I've got a mirror/motor combo in my junk box recovered from an old laser printer. It's a small module with a flat (1/4"?) four sided mirror mounted on a stepper motor. You'd need a second, larger mirror to intercept the output of the first mirror and redirect it to the position on the wall.
  • skylightskylight Posts: 1,915
    edited 2009-01-21 22:51
    Thats exactly how this pocket laser show works

    http://www.maplin.co.uk/Module.aspx?ModuleNo=221731

    The hard bit with rotating mirrors will be tracking an input signal like an ocilloscope does as you will have to synch the rotation speed to the timeline

    to get a waveform say like a sine wave wouldnt it mean a rapid switch of direction not good with motors.
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2009-01-21 23:31


    The "motor" used to position·a mirror in a laser reflecting-positioning scheme is called a galvanometer.· They're available on ebay.
  • kwinnkwinn Posts: 8,697
    edited 2009-01-22 00:40
    How about 2 synchronized mirrors to produce a raster scan and modulate the laser beam?
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