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Thread: Question: ILDA Interface (Projector)

  1. #1
    Join Date
    Mar 2007
    Location
    Eindhoven, Netherlands
    Posts
    51

    Default Question: ILDA Interface (Projector)

    Hey Guys,

    I'm new here on this forum, since my german isn't that good I can't get any answers on laserfreak.net

    I'm building a RGB Projector with the following specs:

    Red 250 mW
    Green 150 mW
    Blue 100 mW
    laptop + easylase usb + mamba black

    I expect to get the parts somewhere next week so I'm already building some circuits.

    Now for my question.....

    The situation is as follows, I put out a signal through my easylase board, this works fine of course then there's gonna be about 20m of cable between the output of the easylase and the projector.

    As I inderstand from the german forum, I'll need a circuit in the projector to change the signals. This is the circuit i found http://www.thaflow.nl/laser/ildainterface.jpg

    The OPaMPs are TL072
    R1..R12 = 47K
    R 17..R20 & R25..32 = 1k

    Will this work, or does anyone have another solution ?

    THNX!

  2. #2
    Join Date
    May 2006
    Location
    Native Floridian
    Posts
    3,081

    Default

    As I inderstand from the german forum, I'll need a circuit in the projector to change the signals.
    The answer to this may be yes and no, maybe. First question, what scanners do you plan on using? If Cambridge or DT-40pro's, then you can eliminate almost half of that circuit. What that circuit does, is convert differential signals to single ended. Most, if not all, of the dpss lasers out there only have single ended inputs. Which really is no problem, you can just connect the cables and it will work fine. Running 20 meters, you may pickup a good bit of unwanted signals at projector causing distortion. The differential signals help to eliminate this problem. The DT-40pro and Cambridge amps accept differential signals, so you don't need to build the circuit for them, but you would need it for the RGB lasers. Another issue is whether or not your DAC is capable of outputting differential signals. If not, and you find yourself having all kinds of noise issues, then you will have to build another circuit that will convert the single ended signal to differential at the DAC before you send the signal down the cable, then the other circuit at the other end to "decode" the differential signal into single ended.

    Will this work, or does anyone have another solution ?
    There's always another way. You can just forget all this nonsense, buy Pangolin and the QM2000.net and just run an ethernet cable to the projector, or better yet, run wirelessly...

    David

  3. #3
    Join Date
    Mar 2007
    Location
    Eindhoven, Netherlands
    Posts
    51

    Default

    Thank you for your reaction

    Stupid me, forgot to mention my scanners

    The scanners i'm going to use are these from http://www.laserworld.tv:
    http://www.thaflow.nl/laser/lw_scanners.jpg

    On their site they only mention their old type, I'm gonna get the new type:

    Scanspeed: 45k @ 5 degrees
    optical angle: 75 degrees max
    input: analog +/- 5V

    The laser-modules have 0..5 V analog input

    The following is from the manual of the easylase-board:
    All outputs are symmetrical and can be used in 3 different configurations:

    1. Symmetrical Signal. Outputs + and - are connected directly with the correspondig pins of the receiving unit. For signal inversion, the 2 lines just have to be crossed.
    2. Single Ended. Output - will be grounded to 0V (GND) and the outputs + and GND have to be connected to the inputs of the receiving unit.
    3. Single Ended inverted. Output + is grounded to GBD and the outputs - are connected to the inputs of the receiving units.
    So if I understand you (and the manual) correctly, I will be using configuration 1. I can connect the scanners directly, and use the circuit for the RGB signals ?


    There's always another way. You can just forget all this nonsense, buy Pangolin and the QM2000.net and just run an ethernet cable to the projector, or better yet, run wirelessly...
    Maybe in time.... Pangolin is very nice, but very expensive..... I don't know how it is in the USA, but here in Holland money doesn't grow on trees

  4. #4
    Join Date
    Nov 2005
    Location
    Melbourne, Australia
    Posts
    3,693

    Default

    Depending on whether the scanners have differential inputs, you may or may not need that portion of the circuit..
    KVANT Australian projector sales
    https://www.facebook.com/kvantaus/

    Lasershowparts- Laser Parts at great prices
    https://www.facebook.com/lasershowparts/

  5. #5
    Join Date
    Jun 2005
    Location
    SoCal
    Posts
    506

    Default

    those looks a lot like the terascans... check to make sure they're not already differential.

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