Need help with making an electric release for the old cable release socket

[gbeal]

I have a couple of DSLR style cameras.
The Sony a700 is all electric. It has a remote socket, and I purchased from e bay a simple programable remote, and intervalometer style remote. Works a treat, set it and walk away.
The other camera is a Fuji X-Pro1, and is proving to be a real handy camera for "pretty picture" type astro imaging. It has a bog-standard old style cable release socket, like all cameras for old used to have. No remote socket.
Up until now I have simply screwed in a cable release, and locked open the shutter (on the B setting) and watched the timer on the LCD operate. When the required exposure is complete I trip the release to close the shutter. This is OK, but if I want to set a sequence of more than about 5 - 6 shots, it becomes a pain.

What to do?

What I want ideally is an electrical "interface". One that accepts the standard mini-jack fitting (I'd buy another remote release as my Sony style has a weird/non-standard fitting). The DIY connection would accept the electrical signal/input from the remote and transfer it into a "push" on the end of the mechanical cable release. The DIY interface could be housed and attached to the hot-shoe on the camera top.
So, while I can make the mechanical bits, the electrical side is way beyond me. I know it must be possible, but I need some pointers and suggestions.
Surely I am not the only one that has this requirement, so there could be a niche/cottage industry going here.
What ya reckon?
Gary

[Steffen]

Jaycar have small push-type solenoids (http://www.jaycar.com.au/productView.asp?ID=SS0903) with 6mm stroke, that should be enough to operate the shutter release. If you hook that up to a mechanical cable release all you need to do is apply 12V and you're shooting.

Cheers
Steffen.

[bojan]

For mechanical part, I would use the low-voltage relay (similar to the one on attached picture). The push has to be strong enough to move the mechanical release and activate the push-button on the camera.

Only one transistor should be enough for the interface between intervalometer and relay, see attached schematic (that depends on relay coil resistance - if it is low, so high current is needed, you may need to use darlington array).
Just be sure not to use VCC higher than 5V, as intervalometer expects 10k pull-ups to 3-5V max inside camera. Also, it would be good idea to place a series resistor (3.3k) at the input of this circuit (D0).

Of course, you have to test this circuit before connecting anything.. Shorting D0 to GND should activate the relay (and your camera) when 4.5~5V is applied as VCC.

[gbeal]

Blimin' heck, cheers guys, so slick and I am bursting with ideas now. Bojan, sorry mate, but the electricSpeak is a tad above me, basic as it is to someone that knows.
I think the first port of call is to try the JayCar solution and see.
Open to any others though.
Thanks again,
Gary

[bojan]

Jaycar solenoid is OK (easier than fiddling with relay mechanicals) , but you still have to interface it to your intervalometer, and for this you need transistors.
The intervalometer is NOT design to drive such relay directly - it just provides short from 5V to ground, and resulting currents should not exceed 5mA.

Maybe you need relay driver with digital input - If I dig something, I will let you know.

[John0z]

There was a device that someone made on the internet - using a servo motor to press the button. I am trying to find it and will post it here if I do find it. Also a intervalometer for a point and shoot camera was available too.

Here is one commercial device http://polepixie.com/pixie-click-remote-trigger.cfm - appears to be a solenoid pushing the button, and allowing for mounting the camera - anyway, we have to use the tripod mount otherwise we need a special housing for each camera.

[bojan]

OK, this will do the job:
http://www.ebay.com.au/itm/New-Stepper-Motor-Driver-Board-UL2003-Four-Phase-Step-Module-Test-Board-Arduino-/280998638011?pt=AU_B_I_Electrical_T est_Equipment&hash=item416cd2f1bb
or this:
http://www.ebay.com.au/itm/Stepper-Motor-Driver-Board-ULN2003-for-Arduino-5V-4-phase-5-line-/160772785983?pt=AU_B_I_Electrical_T est_Equipment&hash=item256ece073f

Actually, it can drive 4 relays from intervalometer independently ;)

But, you still need to do some additional wiring on that board (soldering.. and adding a resistor or two).
If you are comfortable with this, or if you can find someone to help you, I will post the schematic later - it involves adding one resistor, adding one short wire and cutting one track on that board.

[gbeal]

Thank you again Bojan.
If you feel like posting a schematic then I can at least take a look and decide. But I am not electrical clever.
If the schematic is basic enough I might be able to work through it with some help.
Can't hurt anyway.
Gary

[bojan]

OK, here it is.

The first schematic is of that small board, as it is.

The second one is what it should be.
The intervalometer connector is connected at IN4, the rest of channels are paralleled (with associated outputs) to boost loading capacity (as this Jaycar solenoid (marked on schematic as relay) will draw 250mA at 6 V.

NB: this solenoid is not supposed to be used on 12V continuously..
So instead of 12, the whole thing should be powered from 4-6V, not from 12V as indicated on the previous schematic.

[mercedes_sl1970]

Hi Gary - have you had a look at this: http://tempusall.bymac.org/

You can dial in various delays, etc. The only problem can be securing it to the body. I have tried with an X100 but the body shape made it difficult to use. You can get around this by attaching it to a cable release - someone has done this with a Leica M9 on youtube: http://www.youtube.com/watch?v=TrBd8ckJ6Yw

Anyway, might be an option.

Andrew

[gbeal]

Ah, thank you Andrew, I remembered seeing them ages ago. But as you say, difficult to adapt, and if you are going to adapt, why not start from scratch.
I additionally like the idea of a programable remote intervalometer, that way I can program a series of exposures, with a set delay etc.
Gary