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Thread: Does this signal look OK to you...? (no nudity)

  1. #1
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    Default Does this signal look OK to you...? (no nudity)

    Hi,

    I've just added my balanced line driver chips to my highly experimental Arduino DAC - here's the output trace (full differential) for the X axis, when generating a 10 beam fan.

    Does this look OK to you? It ranges from +9.2v to -9.6v (this is the differential signal - so it's +/- 10v ptp).

    I mean, would you send this to an amp?

    The second picture is the output from a Medialas DAC doing the same thing - look how lovely and gentle the transitions are. Would my signal damage the galvo because it jumps directly from one level to another?

    Steve
    Attached Thumbnails Attached Thumbnails Ard2.gif  

    Medialas_diff_output_10_beams.gif  


  2. #2
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    Default

    the return is gentle on the medialas dac for a reason. No scanner will have a step response that matches your return. Can you add a slope to the return in software? I reckon you just to experiment with different slopes and see what yous scanners can handle best.
    What software is outputting to the DAC? Is it your own PIC based signal that you talked about some time ago?

    Rob
    If you need to ask the question 'whats so good about a laser' - you won't understand the answer.
    -----------------------------------------------------------------------------------------------
    Laserists do it by the nanometre.

    Stanwax Laser is a Corporate Member of Ilda

    Stanwax Laser main distributor of First Contact in UK - like us on Facebook http://www.facebook.com/FirstContactPolymerCleaner
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  3. #3
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    Default

    That's what I was afraid of...


    Would it help if I were to do and up/down staircase, rather than just an up/return?

    I'm not sure if I have enough processor cycles available on the Arduino to do smooth continuous transitions like the Medialas. Fortunately for this project I just need a single axis fan - nothing too fancy.

    I'll do some more programming and see what I can do...

  4. #4
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    Default

    sure you just need to run the ramp in both directions but obviusly on the return you need it to happen in a shorter time span. You can limit th enumber of steps to reduce processing as long as you dont get the intermediate points to dwell.
    Or you could do identical ramps in each direction though this may need some trickery to make the beams look the same intensity.

    Rob
    If you need to ask the question 'whats so good about a laser' - you won't understand the answer.
    -----------------------------------------------------------------------------------------------
    Laserists do it by the nanometre.

    Stanwax Laser is a Corporate Member of Ilda

    Stanwax Laser main distributor of First Contact in UK - like us on Facebook http://www.facebook.com/FirstContactPolymerCleaner
    www.photoniccleaning.co.uk

  5. #5
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    Default

    I tweaked the waveform and got the output to look like this..

    So I plucked up the courage and plugged it into an amp - 10 clear beams!!


    [And no smoke!]
    Attached Thumbnails Attached Thumbnails Arduino_diff_10_beams.gif  


  6. #6
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    Default

    wicked.
    A picture of it in action would be cool

    Rob
    If you need to ask the question 'whats so good about a laser' - you won't understand the answer.
    -----------------------------------------------------------------------------------------------
    Laserists do it by the nanometre.

    Stanwax Laser is a Corporate Member of Ilda

    Stanwax Laser main distributor of First Contact in UK - like us on Facebook http://www.facebook.com/FirstContactPolymerCleaner
    www.photoniccleaning.co.uk

  7. #7
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    Default

    In action...

    Just before I set the smoke alarm off, and woke my wife...
    Attached Thumbnails Attached Thumbnails 10beams_arduino.jpg  

    Arduino.jpg  


  8. #8
    Join Date
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    Question

    This for a harp?
    Love, peace, and grease,

    allthat... aka: aaron@pangolin

  9. #9
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    Aug 2007
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    Default

    Yes it is...

    It's only taken me 22 years to get this far...

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