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  1. #1

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    Packard Shutter Mods

    All,
    Im looking around to find a packard shutter to modify (to use on my DIY meniscus project). Here's a quick schematic I drew up; I plan on replacing the pneumatic cylinder with an electromechanical solenoid. I still have some math to figure out, but it should work OK. 1/30th might be abit fast (1/15th might be as well...); as I haven't began to look at actuator speeds yet.
    Both switches will be actuated by a typical shutter release. S1 is to be used for the 'speed' exposures, whereas S2 is a bulb/focusing switch. It isn't the best way; but my electronic engineering is quite limited.

    Thoughts ?
    Last edited by SteveH; 08-07-2006 at 07:57 PM. Click to view previous post history.

  2. #2
    Jon King's Avatar
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    A couple of comments.. S3(the 'bulb' switch?).. will short the LM555 output, which would be low, to your +9Volts. A better way might be add a throw to S2, and make a bulb setting, and trigger it with S1 as you would your normal 'speeds'. The other thing is your timing resistors seem to be set up in a mix between what is normally done as the one shot mode and the oscillator mode. I'm sure you can make it work, but the normal design equations won't give you the right values. Good luck with the lens and the shutter timer!
    Jonathan
    -----------------------------------------------

  3. #3
    jimgalli's Avatar
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    At risk of raining on another re-invention, why not buy an old Tektronix C53 oscilloscope camera and use their circuitry? Plus you get a neat old packfilm holder to mate to your home made lens for instant results. Plus the lenses in these are right up your alley anyways as they were corrected for a rather spherical near surface so they're wacky for normal things.
    He is no fool who gives what he cannot keep..to gain that which he cannot lose. Jim Elliot, 1949

    http://tonopahpictures.0catch.com

  4. #4

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    Quote Originally Posted by Jon King
    A couple of comments.. S3(the 'bulb' switch?).. will short the LM555 output, which would be low, to your +9Volts. A better way might be add a throw to S2, and make a bulb setting, and trigger it with S1 as you would your normal 'speeds'. The other thing is your timing resistors seem to be set up in a mix between what is normally done as the one shot mode and the oscillator mode. I'm sure you can make it work, but the normal design equations won't give you the right values. Good luck with the lens and the shutter timer!
    Jon,
    Ah, thanks for pointing that out. An idea that wasn't thought out - obviously.
    I was going to try the design out tonight; but I cannot manage to find my breadboard. I then learned that RadioShack no longer carries such items !?
    I need to do some more research on the 555 to make sure I have it right; which it doesn't seem I do

    Thanks,

  5. #5

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    Niffty item Jim, checking it out now.

    I like reinventing the wheel it seems. If nothing more, its an excellent way of going poor

  6. #6

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    Jon,
    I found this link;
    http://555-timer.clarkson-uk.com/operation/mono4.html
    That seems to be exactly what I have been looking for (and, failed at making myself). Oh well, at least I am a better machinist than EE

  7. #7
    df cardwell's Avatar
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    Any idea how ACCURATE and repeatable a Packard is ?

    It is.

    .
    "One of the painful things about our time is that those who feel certainty are stupid,
    and those with any imagination and understanding are filled with doubt and indecision"

    -Bertrand Russell

  8. #8
    Jon King's Avatar
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    Well.. I scanned a sketch of what I was thinking, but before that - Jim Galli had a very good idea. If the shutter you can buy will do what you want, and i think with some disassembly and duct tape it might work. What I sketched should work - I'm sure of all but the bulb setting, and it should work. There are differences between what I sketched and what you have - the changes in the switch placement, diode and extra resistor are on purpose. If you want to continue here, or pm, I'd be happy to help out if I can.
    Attached Thumbnails Attached Thumbnails 555 timer.jpg  
    Jonathan
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  9. #9

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    Jon,
    Thanks for taking the time to help me out. I found the issues you pointed out late last night; and made my corrections. Hopefully I can fibd a breadboard and give 'em a whirl.
    Last edited by SteveH; 08-08-2006 at 04:34 PM. Click to view previous post history.

  10. #10
    glbeas's Avatar
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    By attaching a return spring to the linkage in the right place you will be getting down to your average solenoid controlled electronic shutter except it will act like a press shutter, cocking as you trip it. Bet you'll never find a press shutter as big as a Packard! Have fun and definitely show us what you come up with.
    Gary Beasley

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