Microflash to fire optical strobes without using camera's flash

[rtrski 20]

Thinking out of the box, why do the LEDs have to be above the camera? Why not place the LEDs in an area of your housing where there is plenty of room....

 

Technically they don't have to be there, but this is an Ikelite housing, so I've got the clear plastic wall to use whereever it ends up, and I'm trying to avoid any mods to the housing itself (which would include removing the electrical bulkhead and replacing it with something to help with the light coupling). The left side gap between camera and housing is taken up by the existing electrical bulkhead connector - I can tuck it down there if it's being replaced with my circuit on the hotshoe instead. The right side is taken up by the stub end (larkshead loop and plastic clip) of my usual wrist strap, the bulk of which is removed when in-housing but if I can leave that part on it's just easier for converting between land and water use. And of course beneath the housing there's the big slab of the Ike electrical TTL circuitry which also acts as the camera's mount platform.

 

There's also a slight gap between where the top clamp handle rests in the locked position and the top ball mount plate (looking straight down at the top of the housing), providing a nice look-thru space that's also somewhat shielded from scattering forward, and the top ball mount plate is the perfect place to attach whatever I'm using to hold my fiberoptic instead since it's already fitted for a 1/4-20 screw thread. So having the LED's up there isn't really the biggest issue...it's fitting the batteries, frankly. Those I could try to tuck in elsewhere and 'wire' to the hotshoe mount, but its somehow much more satisfying to have a nice coherent part. Looks slightly less bomb-like in my carry-on luggage than a mess of wiring, too, if it's sort of more obviously productized to sit atop a hotshoe.

 

I've got a new circuit laid out that's a bit longer front to back and should put the LED's in a better position (per the gap described above) for me to couple, and with a new attempt at thinning the hotshoe mount I think I've gained about 1.2mm, which should be enough to let me slip in the dual-2032 battery clip vs. the dual 2016. I'll etch the board and re-solder everything this week once the new LED choices show up, after perhaps a quick breadboard to test between the 3 options. I might end up sacrificing the ball mount in the sense of not coming up with both a FO 'receiver' fitting and maintaining the attach point for the ball as well, but that's an easy enough price to pay as I can go back to having a focus lamp off one of my arms if I really need one.

[rtrski 20]

I think I might declare success this weekend. New circuit layout was fit-tested in the housing (paper cutout on the hotshoe mount with the battery holder taped on ), etched the circuit and soldered on all components last night, and was able to fire off the strobe just pointing the FO at the LEDs up to almost 5 inches away with no housing, and 3 inches away thru the housing wall. Didn't test lateral displacement that much but the new LEDs (I used 2 half-watt 'hyper orange' [617nm] Avago surface-mounts, in parallel even though I was the one recommending against that before ) are bright enough I can't comfortably look right at them when they fire, and they've got closer to a 120 deg radiation pattern than the domed 20degree one. So I'm pretty sure this time I can get a fitting atop the housing that will align the FO well enough for reliable triggering.

 

...And, I can still use the sequins to focus the pattern a little more if I need to.

 

Pool tests this weekend, followed by updated project shots including the DIY FO cable and mount, and I'll upload my final circuit image and BOM as well in case it can help anyone else. The new circuit is almost looking like a real product now, since I shaved down the half of the hotshoe adaptor I was using and then mounted the circuit board directly on it using its existing screw holes, and routed the wires from one to the other a bit more invisibly as well. Hopefully that'll calm the TSA dogs a tad when I try to get it thru security. I'll probably still gunk it all up with hotmelt glue as a bit of a potting agent against corrosion if nothing else though (I did tin the circuit before adding components as well.)

 

Thanks to all here for the comments and encouragement.

Edited October 26, 2011 by rtrski

[bvanant 195]

Next step is selling some.

Bill

[rtrski 20]

I don't think I can, at least not in the current incarnation. The fit for mine was kind of particular in terms of the circuit board having to be asymmetric on the hotshoe mount to line up best with the housing bump. Cameras are aligned in the Ike housings with the lens to port, not with the viewfinder position to bump. Then there's knowing how much vertical room you have on any given camera...etc. etc.

 

If I was serious about selling, I'd want to come up with a couple layer circuit board (throw some of the smaller components on the bottom, with the wiring to the hotshoe mount itself), be able to guarantee the battery holder would fit, and probably design in a socket for replacement of LEDs just in case someone manages to shoot fast enough in sequence they burn it out. (Replacement parts, cha-ching! kidding....)

 

And despite how long it took me in particular to iterate thru sizes and layouts....the circuit is pretty danged simple. Now if I could reverse-engineer TTL signalling and have the LED actually preflash/flash/squelch so one could set their Inon to sTTL...now THAT would sell.

 

But I will put up a full product log sometime to help others not repeat some of my mistakes and get it in the first or second iteration.

[rtrski 20]

Well, my LED trigger flash circuit project is finished, including the fiberoptic cable and mounting to both the z240 and the Ikelite housing.

 

Full photo log of the flash development is here. Best viewed as slideshow. Hit 'pause' at the bottom left, hit the 'show info' button at the top right to get the per-picture text info, and then continue thru images at your leisure.

 

http://www.flickr.com//photos/rtrski/sets/...716388071/show/

 

Also for those who want to try their own, I'm providing my bill of materials and circuit board layout and other comments in a powerpoint file attached here for download (Zipped). It includes links to extra details about DIY circuit board etching using a laser printer to make the mask and household chemicals as the etchant vs. anything fancy. Also makes some fit test suggestions to help others get this done in less steps than I did.

 

The fiberoptic DIY cable has been posted in the DIY subforum, here: http://wetpixel.com/forums/index.php?showt...st&p=294502

 

Looking forward to giving this a real workout in Dominica in January!!

LED_Trigg_R_BOM_and_Layout.zip

Edited November 5, 2011 by rtrski

[escape 84]

Very nice rtrski.

 

My led trigger for Nauticam housing ended up like this.

Led module separated(two IR LED 850nm = almost no visible light but it's triggering very well Inon's strobes).

 

 

[bvanant 195]

I don't think I can, at least not in the current incarnation. The fit for mine was kind of particular in terms of the circuit board having to be asymmetric on the hotshoe mount to line up best with the housing bump. Cameras are aligned in the Ike housings with the lens to port, not with the viewfinder position to bump. Then there's knowing how much vertical room you have on any given camera...etc. etc.

 

If I was serious about selling, I'd want to come up with a couple layer circuit board (throw some of the smaller components on the bottom, with the wiring to the hotshoe mount itself), be able to guarantee the battery holder would fit, and probably design in a socket for replacement of LEDs just in case someone manages to shoot fast enough in sequence they burn it out. (Replacement parts, cha-ching! kidding....)

 

And despite how long it took me in particular to iterate thru sizes and layouts....the circuit is pretty danged simple. Now if I could reverse-engineer TTL signalling and have the LED actually preflash/flash/squelch so one could set their Inon to sTTL...now THAT would sell.

 

But I will put up a full product log sometime to help others not repeat some of my mistakes and get it in the first or second iteration.

Isn't that (or the first part at least) what Mattias and crew did to get their TTL converters going? Now all you need is to do (clearly I am joking) is to reverse engineer their reverse engineering.

 

Bill

[rtrski 20]

Very nice rtrski.

 

My led trigger for Nauticam housing ended up like this.

Led module separated(two IR LED 850nm = almost no visible light but it's triggering very well Inon's strobes).

 

(pictures trimmed so as not to spam the forum linking them)

 

Thanks! I have to say your final product looks much cleaner than mine. Almost looks like you sliced the bottom off an old strobe for the mount, and then added the top mount?

 

Those battery holders are nice too...probably easier to swap out batteries than my top-spring clip. But I bet they'd be too high for me, as I can see a little space between them that would add to the overall thickness. Still, very nice, clean integration. I like the locking cord link to the LED's too (from a computer power supply MOLEX interconnect of some sort, right? )

[owfotograaf 14]

"Star Trek Enterprise"

 

My design, uP controlled, supply 2x CR2032, low battery warning, hot-shoe with spring contact,

goes to sleep so no battery consumption when not used (battery's can stay)

red LEDS, (2 cd), can be bent to the fibbers, those not needed can be cut off.

 

 

[rtrski 20]

"Star Trek Enterprise"

 

My design, uP controlled, supply 2x CR2032, low battery warning, hot-shoe with spring contact,

goes to sleep so no battery consumption when not used (battery's can stay)

red LEDS, (2 cd), can be bent to the fibbers, those not needed can be cut off.

VERY nice...you've clearly got access to some good circuit etching capability. And I like those low-profile battery holders as well. I hadn't found anything quite that small but I was searching for 2x stackers vs. using two single-cell holders side-by-side.

 

I'm guessing your chip is on the bottom side, and that's a double-side etched circuit board. Or maybe it's on the hotshoe sub-board?

[owfotograaf 14]

VERY nice...you've clearly got access to some good circuit etching capability.

I'm guessing your chip is on the bottom side, and that's a double-side etched circuit board. Or maybe it's on the hotshoe sub-board?

 

Thanks,

pic controller is located at the bottom and the prototype double side circuit boards are indeed not cheep

[blueglass 3]

Hi

I have been using my original micro flash during 3 trips and thousands of photos, without even changing batteries. It works great with my rig but it didn't work in some other housing if the leds were not properly aligned or when the fiber optic wires are not in perfect condition. So I have made a more universal version, much more powerful that will work with most systems.

This is a pre-serie version:

 

 

I will doing some in water tests next week.

I tested in my friend's Olympus SLR and he could go from 1/180 to 1/400 sync speed without seeing the rear curtain. He was so happy to see he will have much more control over background ambient light.

[oskar 7]

Thanks,

pic controller is located at the bottom and the prototype double side circuit boards are indeed not cheep

 

Nice, i suppose you have implemented TTL with that pick controller, right?

 

 

Cheers

/O

[owfotograaf 14]

Nice, i suppose you have implemented TTL with that pick controller, right?

Cheers

/O

 

No TTL

 

if somebody can explain me how you can transfer TTL trough fibers?(how the length of the discharges can be controlled?)

 

 

With electrical signals you can start the strobe with the X and cut it off (IGBT) with the Q signal, off coarse when the strobe is build for it.

[oskar 7]

No TTL

 

if somebody can explain me how you can transfer TTL trough fibers?(how the length of the discharges can be controlled?)

 

 

With electrical signals you can start the strobe with the X and cut it off (IGBT) with the Q signal, off coarse when the strobe is build for it.

 

Well, i actually meant that if you go the length having a pic-controlled led flash, i suppose it is doing some form of i/eTTL in the sense that it is performing pre flashes as well as reacting at the cut-off signal. If you have a underwater strobe that is said to do optical TTL, that will be enough to let the camera controll the strobe's output.

 

I don't know but I don't thing that any manufacturer has implemented a TTL protocol for fibre, but it would be useful with a standardized data format based on messages rather than propriatory pin configurations and propitiatory data interchange.

 

I made a triggerflash a year ago, but it is just dumb just using the 1ms camera trigger pulse.

 

cheers

 

Cheers

/O

[Guest cor]

The trick is to find out the TTL protocol. Once you know that, you can control it in software using the pic.

[owfotograaf 14]

I don't know but I don't thing that any manufacturer has implemented a TTL protocol for fibre, but it would be useful with a standardized data format based on messages rather than propriatory pin configurations and propitiatory data interchange.

 

That is also my conclusion. And still, many photographers claim TTL works trough fibers with the Inons Z240!

 

@Cor: totally agree, if you work with electrical transfer TTL protocol is needed, like HW converter does, they now the protocol ..... almost

[Guest cor]

oskar..que? My inon Z240s do TTL over fiber with my D7000 popup flash. Tested it for accuracy on my recent trip and it's pretty good. If only we could get their timing data, then making your own TTL in a DIY hotshoe led connector would be easy.

[Nicool 30]

Hi all!

Maybe the device that Nauticam are building for their Nikon D4 housing will have this TTL compatibility?

And would be re-usable in my Hugyfot D7000 housing!!!

I'm mentioning Nauticam, but kudos to you guys for being precursors in this direction!!

[oskar 7]

There was a bit of TTL confusion in this thread before.

 

* The popup flash of the camera will do TTL. If you connect it with a fibre to an external flash that supports "TTL pre flash mimicry" you get TTL with that too.

 

* I think the confusion come from that the hot shoe has a standardized middle pin that will give short pulse (1ms) when the main flash should go. Without any TTL. This function is the same for most cameras.This is what I use to trigger my microstrobe. Any power adjustments must be done on the strobe.

 

The thing with getting TTL with a microflash, or any ordinary hot shoe flash for that matter, is that they must use the TTL protocol of the camera. This varies between camera makes (e.g. Canon and Nikon are different). This "protocol" involves both different pin layout in the hot shoe connector and different signals. It is not rocket science and it's definitely doable.

 

And now we're waiting for the first one to produce a TTL microflash ;-)

 

 

Cheers

/O

[tamas970 12]

I'll give a try to the project using a 1W IR LED. I was wondering, can I power that using 2x CR2032's?

 

Another electronic question: My camera (E-PL5) is theoretically capable of 1/400sec sync speed. This means, the microflash should react in <0.1ms. Do I need to get a special MOSFET or another LED to make the system as fast as possible? Or a stronger power source (e.g. 2x CR2)/higher current is the deal?

 

The irf540 datasheet talks in nanoseconds - should be fast enough...

Edited June 24, 2013 by tamas970

[Shaff 0]

Hi

I have been using my original micro flash during 3 trips and thousands of photos, without even changing batteries. It works great with my rig but it didn't work in some other housing if the leds were not properly aligned or when the fiber optic wires are not in perfect condition. So I have made a more universal version, much more powerful that will work with most systems.

This is a pre-serie version:

 

 

I will doing some in water tests next week.

I tested in my friend's Olympus SLR and he could go from 1/180 to 1/400 sync speed without seeing the rear curtain. He was so happy to see he will have much more control over background ambient light.

 

Hi,

 

Any way I can buy one of these? Will it fit a Nikon D300 with a Nauticam Housing?

 

Cheers

Edited December 3, 2013 by Shaff

[Alvaro Velloso 0]

Hi everybody,

 

I'm planning to do a kind of Microflash by myself if Carlos did not put it into production soon .

 

Some improvements I would try:

 

- 5.5V 1F super capacitor (rechargeable) instead of coin batteries.

- Microprocessor for special strobe effects, like delays and multiple triggers.

 

If I had the time I would implement S-TTL as well, but it is a lot of work.

 

Kind regards,

 

Alvaro

[marcw 8]

Hi everybody,

 

I'm planning to do a kind of Microflash by myself if Carlos did not put it into production soon .

 

Some improvements I would try:

 

- 5.5V 1F super capacitor (rechargeable) instead of coin batteries.

- Microprocessor for special strobe effects, like delays and multiple triggers.

 

If I had the time I would implement S-TTL as well, but it is a lot of work.

 

Kind regards,

 

Alvaro

any luck?