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Thread: TTL for shutter. Can't get it to work correctly, any ideas?

  1. #1
    Join Date
    May 2005
    Washington D.C.

    Default TTL for shutter. Can't get it to work correctly, any ideas?

    Okay heres where I'm at:

    I'm currently in the process of building my first laser projector. I have my scanners working, and the beam table I engineered, but the problem is with getting the shutter to work. I'm using a 12vdc 900mA power supply, a 12vdc ledex solenoid, a 12vdc 2amp relay with a 5vdc 42Ohm coil.

    When I apply 3vdc @ 100mA to the relay coil, it snaps and the shutter works, although when I connect it to the TTL line of my DAC card, the relay does not work.
    I have also tried a 30vdc 2amp relay with a 4.5vdc 145Ohm coil, with the same result.

    Any ideas?.. Thanks for the help..

  2. #2
    Join Date
    Feb 2005


    Hi jayDC...Welcome Aboard

    Looks like you will need to find a driver for the relay.

    One possible way is to use some discrete components like a darlington transistor and a few resistors..with a separate power supply ,
    prolly +5 but a few extra volts wont hurt...
    ..the resistors are for current limiting..etc..
    Another way would be to use a Darlington Array IC for example ULN2003.or just about anything in this family.
    It is made specifically to drive relays , lights ., leds...or other current hogs. ...directly from a low current source like the TTL output of your PC...

    I'd look up simple relay driver circuits on the internet... you'll find a slew of stuff..

    Good luck with your project...
    "My signature has been taken, so Insert another here"
    *^_^* aka PhiloUHF

  3. #3
    Join Date
    Feb 2010
    Melbourne, Australia


    Quote Originally Posted by Adrian View Post
    You have no need to worry about these shutters some time they create problem but you just off your shutter and
    return on after 5 or 10 minutes i hope you remove your problem
    Woah, I'd hope he's sorted out his problem since it was reported over 7 (SEVEN) years ago! Nice of you to be concerned and all...

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