photographic flash trigger

Discussion in 'General Electronics Chat' started by rover999, Dec 5, 2007.

  1. rover999

    Thread Starter New Member

    Dec 5, 2007
    3
    0
    Hi I am looking for some one to help me please
    My daughter is keen on photography and has asked for my help I am so lost has any one the time to assist me please.
    This is what I am after I want to build a sound and or light triggered switch that has an adjustable time delay in fractions of a second to operate an output.
    The idea is she will be able to use this device to fire a flash to do stop action photographs.
    There are devices described on the internet but look to hard to understand by me.
    If you think you can help please contact me
    Al
    my email is alb1955@hotmail.com
     
  2. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    Do you have information on the amplitude and duration of the pulse needed to trigger the flash? I imagine it would be in the user's manual for the strobe.

    hgmjr
     
  3. boltcutter

    Member

    Dec 5, 2007
    19
    0
    Back in the old days the strobe would be triggered by a mechanical switch slaved to the camera's shutter. In practice now, 1/100s and as close to zero resistance as you can get (many modern flashes have very low trigger voltages) would probably do. Unfortunately old flashes often have very high trigger voltages (200V+), so probably an SCR would be a good idea.
     
  4. rover999

    Thread Starter New Member

    Dec 5, 2007
    3
    0
    hi the trigger once fired it can stay on for up to a second
    the output will require to be a set of contacts as the power is from the flash unit
    the flash unit will fire onle once per shot the kind os shots she wants to take are things like a ballon burtsing of drops of water
    Al
     
  5. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    Your description of the strobe firing input is consistent with boltcutter's comments.

    There should be a simple sound triggered circuit on the internet. I will look around for something. In the meantime maybe boltcutter has a favorite circuit to suggest.

    hgmjr
     
  6. GS3

    Senior Member

    Sep 21, 2007
    408
    35
    This is a bit vague but, in general terms all you need is a 555 to create the delay and an SCR to trigger the flash.
     
  7. boltcutter

    Member

    Dec 5, 2007
    19
    0
    I do believe I recognize part of this circuit! ;-)

    If she's looking for water drops, probably an IR emitter / darlington pair is the best bet. Perhaps connect the schmidt triger part of this circuit

    http://www.hiviz.com/tools/triggers/makeown.htm#pg

    to GS3's debounced delay circuit.

    Aim the emitter at the receiver and arrange to let the drop fall between them. Set the gain such that the circuit doesn't fire until the passing drop lenses enough extra light into the darlington.
     
  8. rover999

    Thread Starter New Member

    Dec 5, 2007
    3
    0
    hi thanks everyone for your help just ordered a klit of parts from the link in the above message just hopes it comes soon before she drives me mad
    thank you all for all yourhelp
    Al
     
  9. GS3

    Senior Member

    Sep 21, 2007
    408
    35
    Cut'npaste works wonders :)

    > http://www.hiviz.com/tools/triggers/makeown.htm#pg

    That is a really good link. Thanks. I have an old flash which I have thought of using as a slave flash to light up backgrounds. I may finally get started with this project.
     
  10. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    Greetings rover999,

    Looks like you have received several good suggestions and have selected one to run with. That's terrific.

    We would appreciate an project update once you get things operational.

    What would be really interesting would be a sample photo taken by your daughter of a bursting balloon or other subject.

    hgmjr
     
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