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Thread: Somebody needs to get this kid into lasers

  1. #1
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    Default Somebody needs to get this kid into lasers

    Check out what this 15 year old did with an oscilloscope

    http://www.makezine.com/blog/archive...C-0D6B48984890

  2. #2
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    Default

    very cool.
    i like where he has the images dripping like water.

  3. #3
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    Nice! More proof that soundcards make really good DACs.

  4. #4
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    Lightbulb

    I don't know much about oscilliscopes, but couldn't you hook one up to a "Laser Boy" set up and get results like that? Wouldn't it be like running a show to scanners? I would think he could hook a set of scanners to where he hooked the scope up to and the scanners would draw the same thing. I don't really get what he "did"...

    Looks cool thought...
    Love, peace, and grease,

    allthat... aka: aaron@pangolin

  5. #5
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    Yes, you are right and perhaps he even stole the idea from LaserBoy or maybe he was even using LaserBoy to create it... who knows.

  6. #6
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    Smile

    I don't think he was using laserboy because laserboy is smart enough to limit the slew rate of the signal you send to the sound card so that you don't exceed 30kpps to your galvos. (And yeah, I know that 30kpps is a vague number that doesn't translate well to Khz...) Nevertheless, if you look at what's going on in that oscilloscope demo, you'll see that it's *got* to be running at an effective speed that is *way* faster than 30kpps.

    Remember that a good sound card can accurately reproduce a 20Khz audio signal. That's nearly 10 times faster than the maximum small signal bandwith for a set of 30Kpps galvos. So the kid is probably feeding his custom waveform to his sound card at the maximum rate. Since he's using an oscilloscope to display it he doesn't need to be concerned with speed... The sound card will run out of bandwidth way before his scope will.

    It's a neat demo, and I'm impressed at the work that went into creating it, but if you hooked the output of that sound card to a set of scanners I think you'd end up with hash. I don't think any galvo set could keep up with that demo - it's just got too much going on.

    I agree that we need to introduce this guy to lasers and scanners though! I'll bet he could do great things... But he's going to have to get used to a lot less bandwidth.

    Adam

  7. #7
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    I think I know the person who did that. A sophomore at my school. He was doing pictures on the oscilloscopes at school with a laptop and extigy. I have to ask him about it. There are certainly people 100% capable of that at my school.
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  8. #8
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    Hey Ben...

    If it is the same guy, send him an invite to PhotonLexicon. For that matter, you might also want to show him James Lehman's Laserboy site.

    Maybe the guy isn't interested in lasers... But more likely he's never even considered it as a natural extension of his demo hobby. (Just think of how much more impressive his demo would be running on an RGB projector!)

    It can't hurt to ask...

    Adam

  9. #9
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    For sure, when I get m projector built, I'll show it to him and see what he can do with it. I'm sure he would be interested, he is into high power flashlights and other related hobby stuff. I worked with him to build a Jacobs latter inside a high pressure argon tube, very cool effect.
    CLICKY!!!

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  10. #10
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    "Remember that a good sound card can accurately reproduce a 20Khz audio signal. That's nearly 10 times faster than the maximum small signal bandwith for a set of 30Kpps galvos"

    Huh? Most sound cards will do 48K samples per seconds which means the max output is 48K pps. But still, galvos can't even handle 30kpps if the jumps are from min to max angle. Oscopes can handle any step size.

    Also, I have found that the output on a scope from a soundcard looks different than that of a normal DAC. If you look at the output from a normal DAC you will see a bunch of dots on the screen that translate to the points you are drawing. But, if you send these points to a sound card you will see continous lines between the points. What I think this means is that normal DACs change the X/Y values instanteously but a soundcard will ramp the voltage to the next one linearly over the sample time period. I am curious to know which type of signal change is more preferable to the galvos/amps.

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