Design help needed with packard-style shutter, flash sync and timer

[rotomotor]

Hi,

I've been on a quest to put a shutter behind a 42cm Heliar on a 9" lensboard so that I can shoot portraits more easily and use flash sync. Last week, I bought a shutter on ebay that had the rare opening that the Heliar needs: BIG. It arrived Saturday, and by last night I actually had a working shutter with flash sync. Incredible progress for such a short period of time. Of course my partner would like me to pay attention to her and not just talk about shutters and flash sync. However, I digress.

This shutter has a solenoid on it that after trying many different batteries, and DC wall adapters, I found that it works with both 12V and 24V DC power. So far, I am using my enlarger timer at .2 seconds which results in a fastest shutter speed of about 1/4 second. For flash sync, I went to a local surplus store and found a micro switch. Low and behold, the switch is wired to the end of a pc sync cable and it works! I made a test 8x10 last night and it looks great.

Here's what I would like to do:

• If possible, use a battery to drive the shutter. Will a rechargeable battery put out 12V 500mA for a few minutes of focusing and a few shutter activations?
• Use a timer, perhaps like a 555 timer and add selector switch to choose between my fastest speed of 1/4, then 1/2, 1, and bulb
• Attach some sort of push button, or even better, a remote control so I can have more batteries and complexity to fail

Maybe just a wired switch!

I'm amazed that I've made it this far as I am just a hack with epoxy, tape, and DC power supplies lying around. Can someone point me in a good direction to bring this up a step so I can lose the enlarger timer, and go to battery power if possible? I can follow specific directions well, design a timing circuit on a breadboard? Iffy at best!





Any expertise in electrical engineering is MOST APPRECIATED!
Thanks,
Scott

I know that this has been covered before with slightly different variations but I don't think my specific task has been covered. Other reference threads that I've found on the subject:
http://www.f295.org/Pinholeforum/for...?m-1237050311/
http://www.apug.org/forums/forum147/...tter-mods.html

[rotomotor]

Here's the pretty side of the camera:

[William Whitaker]

It's great that you've gotten as far as you have, but perhaps it would really simplify things to use a pneumatic-type Packard shutter. That way you could lose the timer and the battery with no reliance on electrons. It's like life off the grid...

[Jim Jones]

You could design a mechanical time exposure control, and use a battery for exposures. It takes more current to energize a solenoid than to hold it in the energized state. An electrolytic capacitor charged to full battery voltage through a resister that limits current to the hold-in current of the solenoid will save battery power. Electrolytic capacitors can leak electricity, so you'll also want an on/off switch. There are many rechargeable batteries and battery packs for tools, toys, photo gear and electronics devices that might be found in thrift shops. Exposures from 1/4 second to several seconds can be controlled by counting seconds. A wind-up clock that ticks four times a second is a great training device for this. A digital clock that clicks once a second might do as well.

[jp]

item 320845098128 is a timer 0.01s to 99h99s and available to run on DC power.

Something running D-cell batteries or a gel cell like in an alarm system or UPS would run your solenoid and timer for a very very long time.

[jp]

item 320845098128 is a timer 0.01s to 99h99s and available to run on DC power.

Something running D-cell batteries or a gel cell like in an alarm system or UPS would run your solenoid and timer for a very very long time.