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Thread: Laserworld 250mW TTL blanking usage query

  1. #1
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    Default Laserworld 250mW TTL blanking usage query

    Just bought a 250mW green laser from Laserworld that features TTL blanking. There are 2 wires coming from the PSU (red, black) marked TTL.
    So far, I have found that momentarily touching these wires together blanks the output, although not totally.
    Main thing I want to achieve is to drive the TTL blanking from a standard ILDA socket.
    Seems like there are 3 possible connection options to the ILDA socket -
    a) Pin 13 (shutter) and pin 25 (ground) or
    b) Pin 6 (Green +) and Pin 19 (Green -)
    c) Pin 6 (Green +) and Pin 25 (ground)
    The first 2 options would give a 5 volt range but the second option will have the wrong ground reference; however, if the TTL black is not internally grounded, perhaps it would be OK to connect to the G- pin?
    The 3rd option is only 2.5 volt range but has the correct ground reference - will this be enough to switch the laser on/off - I've always thought of TTL as being 5v on, 0v off but I know this is a simplistic view!

    (I'd rather use the green control signal if possible as I'd like to keep the shutter option as a safety feature. I know this is an analogue signal but if I am just using 2 states, it should be OK)

    Any assistance appreciated! TIA

  2. #2
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  3. #3
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    Default

    Cheers Lampy - I'll try that - just waiting for USB interface and software from same source, have reserved the weekend for laser building so hope to have something usable by next week.

  4. #4
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    Default

    As Laserworld supplied the laser, I thought I'd ask them the same question - here's their reply :

    ILDA Connector - You have to connect PIN 6 (+) and PIN 19 (-).
    When you connect both TTL cables, there is a protection inside in order not to kill the PSU driver ;-)
    So it looks like there are a couple of possibilities, I'll try both at the weekend and see which is most useful.

  5. #5
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    Further to this, I asked Laserworld about using the blanking connection with their USB interface and software and got this reply :

    intensity is not connected on the USB, but you can switch all colors to green in the software options
    so for me, at least, looks like I'll be connecting the TTL blanking to the Green + and - pins on the ILDA socket.

  6. #6
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    Cool

    Right. I also replied in the other thread, but since you've got more info here...

    Ordinarily you'd use pins 3 and 16, but since intensity isn't connected on your DAC, you'll have to use the green color signal (pins 6 and 19) and then switch all colors to green in your software. It's an extra step, but it will work.

    Adam

  7. #7
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    Nov 2007
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    Thanks for all the help on this topic, I'm really looking forward to the weekend when I hope to get all the parts assembled.

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