Build your own Ghostmaster

[Neal Chaves]

I have decided to "open source" my Ghostmaster invention. The Ghostmaster is a flash fire control system for leaf shutter cameras. The circuit provides for electronic flash synchronization at shutter opening or closing, or a combination of both with two separate optically isolated channels. Powered by its own internal 9V battery, the Ghostmaster can provide protection for any camera from the high synch voltages and currents of older strobes, up to 400V.

The Ghostmaster was patented in 1996, but the patent is now in the public domain. However, after I began production of the product, I refined the circuit for increased reliability and component availability, and I never made these changes public until now.

The current demand for the device is not great enough to warrant quantity production, and there is some hand work involved. Perhaps some of our members might be interested in building the device for themselves. I have a number of the circuit boards on hand, which greatly simplifies construction and miniaturization. All other components are commonly available at electronics suppliers.

You can find complete details by searching US Patent 5,530,320 and I have attached the revised schematic.

Neal

[WayneStevenson]

So what exactly does this do Neal? My understanding of leaf shutters is that they trip the sync as soon as the shutter is fully opened?

So this will enable you to either trigger the shutter once fully open (as would happen without your device), or right when the shutter starts to close (like a rear-curtain sysnc)?

[searover]

I have decided to "open source" my Ghostmaster invention. ...
I have a number of the circuit boards on hand, which greatly simplifies construction and miniaturization. All other components are commonly available at electronics suppliers.

You can find complete details by searching US Patent 5,530,320 and I have attached the revised schematic.

Neal

So Neal, What would you charge for the Circuit Board and Who's box did you design it for? PacTec is just down the street from my shop - any chance its one of theirs? I might get a few sample boxes if anyone is interested in them.

John

[Steve Smith]

Two comments:

1. I can't see the benefit as they can be fired directly from the sync socket.

2. It's possible to make a circuit which fires a flash from an opto-triac without the need for a separate battery. You use the trigger voltage of the flash to charge a small capacitor through a high value resistor then the shutter contacts discharge this into the LED.

92291

Put two (or more) opto triacs' LEDs in series to fire more than one flash - only derive power from one though.


Steve.

[BrianShaw]

So what exactly does this do Neal?

1. A flash fire control system for leaf shutter cameras to manage a single shutter synchronization pulse for a plurality of electronic flash units, said flash fire control system incorporating switch-selectible modes for a plurality of electrically isolated synchronization output triggers to configure said output triggers for either simultaneous and instantaneous triggering of all of the said plurality of electronic flash units upon the opening of said leaf shutter, or the instantaneous triggering upon opening of said shutter for one or more of the said plurality of electronic flash units and triggering upon the closure of said shutter for one or more of the said plurality of electronic flash units, comprising: (bla bla bla... patent material)

[bob carnie]

I dare you to say that again three times fast.

1. A flash fire control system for leaf shutter cameras to manage a single shutter synchronization pulse for a plurality of electronic flash units, said flash fire control system incorporating switch-selectible modes for a plurality of electrically isolated synchronization output triggers to configure said output triggers for either simultaneous and instantaneous triggering of all of the said plurality of electronic flash units upon the opening of said leaf shutter, or the instantaneous triggering upon opening of said shutter for one or more of the said plurality of electronic flash units and triggering upon the closure of said shutter for one or more of the said plurality of electronic flash units, comprising: (bla bla bla... patent material)

[BrianShaw]

Can't... and won't even try for fear to totally embarassing myself. I'd sure like to understand how the said 9v electrons know the point of said triggering or the said closure of the said single shutter sychnronization before informing the said plurality of electronic flash units. All this time and heretofore I thought the said single shutter only made contact at the said full open position of the said shutter leaves.

[Neal Chaves]

I'll try to answer all your questions. The Ghostmaster was originally designed to duplicate the "second curtain synch" effect which appeared on 35mm focal plane shutter cameras in the early 1990s, but do it with most leaf shutters. One day I was working on a Compur shutter and noticed that the shutter contacts broke while the shutter was starting to close but the shutter blades were still wide open. I knew that an electronic circuit could fire a strobe at that point, just as a mechanical automotive ignition dristributor fires a spark plug when the points open. I had a simple circuit working in a few days, but soon encountered a number of problems that had to be overcome.

All mechanical switches bounce, and if the circuit was too sensitive I would get synch at both opening and closing. This produced some interesting effects, so I designed the circuit with two optically isolated channels. Because it has its own power supply, neither of the Ghostmaster sych outputs are polarity sensitve. With two strobes connected, one can have a sharp image of a moving subject with a motion streak and another sharp image at the end of the exposure. Split diffusion and split filtration are simple to accomplish. The Ghostmaster works best with Compur, Prontor, Compound, Copal, Ilex, Kodak and Wollensak X-sych shutters. Seiko shutters may be partially closed when the Ghostmaster synchs, although the Seiko shutters on Mamiya RZ67 synch when wide open.

There are optically isolated "Safe Sych" circuits on the market, like the one from Wein Products Co., but the Ghostmaster requires its own power supply for closing shutter synch so I used that for the optically isolated instantaneous channel. My circuit board is made to fit in the PacTec No. "K-HM" case. If there is interest, I will package a circuit board, parts list and construction tips for $5 plus postage. I sold a great many of these units for $129 and wholesaled them for $75 to suppliers like Flash Clinic in New York for $75. It received a rave review from a certain Shutterbug Magazine editor who is now doing life without parole in Lynchburg Federal Pen. I gave a two year warranty and none were ever returned.

[coisasdavida]

It received a rave review from a certain Shutterbug Magazine editor who is now doing life without parole in Lynchburg Federal Pen.

I completely missed this when it happened. He has a website up in his defense. Complicated stuff.

[Neal Chaves]

Here is a photo of the two versions I made, the monoplug and the H-type (household, Honeywell). You can see two female PC sockets on the lower left side. The top PC is an optically isolated instantaneous synch. The lower PC is switched to instantaneous or delay by the slide switch, as is the monoplug and the H-type plug. Input from the camera shutter goes in the phone jack or the H receptacle. A test switch simulates shutter fash contacts. These units are built in the PacTec "K-HM" case.92458

[Tim Meisburger]

Sweet! I'll have one. I'll PM my address and PayPal the money, if that is okay. I'll probably have to source the additional parts in the US, so if anyone else has ideas where to get those, please pass them on.

Best, Tim

[WayneStevenson]

" If there is interest, I will package a circuit board, parts list and construction tips for $5 plus postage. "

Thanks Neal. I'm in. :)

[Neal Chaves]

Please don't try to order a circuit board from this DIY forum. This is not for buying and selling. I will put up an ad in the classifieds once I complete the documentation, or you can PM me now. I will build a few more in the next week or so and photograph the assembly stages, and I will also build one in a larger enclosure.
Neal

[Neal Chaves]

Thanks for the interest and your patience.

There is one component value in the schematic I released that has not been updated. Electrolytic capacitor C1 should be 47uF/25V not 10uF as shown. The circuit will work with C1 at 10uF, but I found that well-worn shutters can have bouncing flash contacts which lead to unreliable Ghostmaster operation. Increasing the value of C1 helps to tame these bounces and provide good closing shutter synch at speeds up to 1/125. Most special effect work with closing shutter synch is done at much longer shutter speeds in any case.

I originally designed the isolated instantaneous part of the circuit to use the Clare LCA110 with FET output. This IC was fairly new and although it offered several advantages, it was somewhat expensive. When I figured out a way to use the much less expensive triac-output MOC3010, I switched to that. One additonal small cap ,C2, is needed with the MOC3010.

I just ran out of MOC3010, and as I only intend to make a few more Ghostmasters, I am not going to order any more. I have about ten LCA110 left fom my early production, and I am going to use those up. The current DigiKey price is $2.20 ea. for LCA110 and .72 ea. for MOC3010 (plus you need a small cap.) This is no big deal if you are only building one or a few, and I will provide details of how to use either IC. I'll have the circuit board ad up on the classifieds later tonight.

Neal

[Neal Chaves]

I built a circuit with the LCA110 yesterday and found that although the isolated instantaneous synch worked reliably with Vivitars and my newer studio strobes (Norman and Photogenic), it will not fire Norman 2000Ds. As I mentioned above, all the Ghostmasters I have sold used the MOC3010 (now MOC3010M), so I never knew of this glitch before. I can not think of any logical reason why the LCA110 cannot fire a 2000D. The synch voltage is 28VDC. I don't have a scope to examine the Norman 2000D synch current, but there may be something about it that is not compatible with the MOSFET output of the LCA110. No doubt one of you smart guys can figure it out, but I suggest using MOC3010M as it works reliably and is more common and less expensive. Because the MOC3010M triac output has a very low holding current, it does require a resistor-capacitor network, R2-C2, to keep it from latching on the DC strobe synch current.

[Neal Chaves]

The following series of photos shows construction of a Ghostmaster device in a PacTec K-HM case with monoplug hardware. I am presently building the circuit into a larger project box, the Velleman G304 and will show this only slightly larger, but much easier build when complete.

In the first and second views we see the board being "populated" with components and connection wires. It is important to use light weight stranded (not solid), flexible hook-up wire, as soldered traces on the board are delicate and could be broken when fitting the circuit into the case.

When the circuit is complete, it should be tested before it is fitted in the case, 3rd view. Clean off any solder flux residue from the circuit board with an old tooth brush and acetone.


9323893239

[Neal Chaves]

Then glue the board and the input and output receptacles into the case with 5 min epoxy or plastic glue. When cured, test with the strobe again. View 4. When it tests OK, pour the circuit area with epoxy or polyester resin. View 5. Finally, when resin has set, close up the case and test one last time. View 6.932419324293243

[Neal Chaves]

Here's the Ghostmaster built in a Velleman G304 ABS project box, 115x65X40mm, which provides considerably more room in which to work. In the first view I have installed the monoplpug jack and plug and the PC fittings. I have also glued in place three partitions of 1/16" hobby plastic in the existing circuit board slots. The slots are sized for a circuit board slightly larger than the Ghostmaster board I will use. On the middle partition I have placed some Velcro on which I will attach the Ghostmaster board.

In the second view, I have installed the circuit board and wired it in place. I used panel-mounted switches for the test button and instant/delay switch. Unlike the smaller PacTec case, the only machine work on this Velleman case is simple hand drilling of mount holes. After wiring is complete, I test for proper function, before pouring the circuit board and monoplug compartments with polyester resin.
935489354993550

[Neal Chaves]

Now you see the completed Ghostmaster hooked up to two Norman power packs and fitted to a Photogenic monolight. The Photogenic does not offer sufficient clearance for the Ghostmaster to plug in directly. Here the additional clearance is provided by a 1/4" mono to stereo headphone adapter like the Radio Shack Cat. No. 274-1501A
9355193552

[WayneStevenson]

Thanks Neal. :)

[Neal Chaves]

I had a nice long talk with Brent Hollister of Holly Enterprises , Los Angeles, California, one of the world's foremost experts in electronic flash. Holly Enterprises has been a Norman factory repair facility since the founding of Norman. Holly can repair other brands as well.

Brent verified that as I has suspected, the 2000D sync voltage is not pure and clean DC, and that this can cause problems when trying to trigger from an optoisolator. He suggested a newer component with much better performance than the MOC3010. It is the IL420. At $3.79 for one at Mouser it is considerably more expensive than MOC3010, but well-worth it if you use Norman P2000Ds. As many photographers know, the P2000D, especially the late production units (SN over 100,000) are some of the most rugged and reliable power packs available today, and can be easily repaired if required.

Holly Enterprises - Los Angeles, California

Orders/Repair - 800-988-7111

Tech Advice - 818-892-9020

[Neal Chaves]

I just put two demo units up for sale on the classified section.
Neal

[daydayyang]

Are they still available for sale? I'm interested in buying two, if the device allows me to set Copal shutter to T and sync the flash right before I trigger to close the aperture. Thanks in advance, Neal.

ps: Called Flash Clinic today since I live not far from NYC. Sadly they only do repair nowadays, no more sale or rental service.


I just put two demo units up for sale on the classified section.
Neal

[Neal Chaves]

I have parts to make two for you. The Ghostmaster will work on B or T with Copals, firing a flash just as the shutter closes. Of course, it can do much more than that as it has two optically-isolated channels and can fire one strobe as the shutter opens and another as the shutter closes. This make possible a number of different "split" effects, like split diffusion, split filtration and split focus.

[Will Frostmill]

Does this mean the circuit could be modified to have an adjustable delay, so it could fire at the correct time for M type flash? There aren't very many shutters that are non-x, but there are a few. For that matter, could the design be extended to trigger a series of flash units sequentially, to give flash synch for Speed Graphic type focal plane shutters?

Will

[Neal Chaves]

Shutters that have M synch actually close the switch before the shutter is fully open to give the bulb time to reach full output. FP (focal plane) flash bulbs have a long peak burn to provide even illumination during the travel of the focal plane slit, they too are set off before the shutter curtain starts to move. The Ghostamster circuit offers no advantage with flash bulbs.

[Tim Meisburger]

I bought one of these (circuit board and instructions) but was overly optimistic about my electronic skills (i.e. you need to actually know something about electronics to make this). Anyway, I got it and shoved it away in a drawer and just found it again. If anyone wants it you can have it for postage, which will probably be less than the $5.00 I paid for it.

Cheers, Tim