trigger a camera remotely, with a twist

I have a film camera, a Mamiya 7, which I want to trip remotely.

I have an existing radio control transmitter and receiver, specifically the type sold on fleabay to trigger off camera flash units. The 433 Mhz transmitter is mounted to the camera hotshoe and the 3V (two AAA batteries) receiver is velcroed to the flash and is connected to it via mini jack or the like. Taking a picture trips the flash. There is also a test button on the transmitter to fire the flash manually.

What I envision is a minute button, not necessarily a solenoid since they all seem too large for this job, that when 3V is applied to it expands to fill an approximate 1/8" gap between itself and the Mamiya 7 shutter release button. A push button to push a button, as it were. The travel to release the shutter on the camera is only 1/16" or so and requires only a tiny amount of force. I can find a way to mount it if I could find the proper doodad itself. Ideas?

You are lucky because your camera has a switch. There is a lot that have not.

Google for the sites of people taking pictures from kites. Lot of examples.

Very nice camera - can't beat those big negatives!

The Mamiya does have a cable release socket (I can see it in the pic you attached). What would it take to rig a small solenoid to push the end of a standard cable release? I'd imagine that could be built into a small box that you could mount the radio trigger receiver on to, and hang the whole thing from the tripod. Good luck!

Chris

It still amazes me that in expensive cameras like that they don't spend an extra 10 pence to put a socket in for electronic remote triggering.

A hobby servo would probably do the job, and probably most neatly in a box at the end of a mechanical remote shutter cord. You will need to measure the force required to reliably trigger it (just use a weight), then find a servo with the right torque.
A microcontroller can easily control the servo but there might be off the shelf servo controllers that will do the job.

I've seen the kite rigs and they tend to be relatively large, clunky and ugly, but I'll spend more time on that, perhaps someone has managed an elegant solution.

The cable release/solenoid is a great idea with more applications (large format lens remote trigger - now that would turn some heads) but I actually thought this would be easier. I was planning to use the cable release socket to mount a rigid L shaped arm holding the push button trigger, letting the battery hang or be velcroed to the side.

It seems to me the success of this project depends on finding the right servo/solenoid and building around it. That's what I'm having the most difficulty with, and possibly why no one has done this yet in all of googledom that I've scoured.

I believe the best solution is a linear solenoid, soft shift I think they're called, that don't explode out of their resting state but are more gradual but still rapid enough.

I'm actually thinking a home made solenoid is going to be required. I've seen some like the TO-5 but good luck getting just one or two from anywhere.

I did realize last night that the receiver I have that runs on 3V is not going to provide 3V to the switch itself, probably just a switch being closed upon triggering it, so I'm not sure what's next..

Thanks for the input everyone!

Broadening the parameters a bit, does anyone know of a relay with a physical component that could be made to do the work? I'm thinking of employing the electromagnet inside to change states and cause the button to be pushed.

Another idea, are there any bi-metallic strips/devices that pop or flex under voltage that might work here?

It's funny, I've seen the behavior in so many places but simply can't find the right form factor, small, to put this together.

Look for RC servos able to move something longitudinally or just actuators as the one you showed (nice thing, have to say).

nSomnius said:

Broadening the parameters a bit, does anyone know of a relay with a physical component that could be made to do the work? I'm thinking of employing the electromagnet inside to change states and cause the button to be pushed.

Another idea, are there any bi-metallic strips/devices that pop or flex under voltage that might work here?

It's funny, I've seen the behavior in so many places but simply can't find the right form factor, small, to put this together.

Click to expand...

Have you thought about a small speaker/earbud? Maybe you could find one with sufficient amplitude.

I like your thinking tracecom. I'm really starting to think I'm going to have to construct an electromagnet in the right form factor for this to ever happen.

Might be able to modify a small 3V coil relay. I know Goldmine has some 4.5V ones that I believe will pull in with 3V

A source of smallish solenoids is old point and shoot 35mm cameras. These two are pull type and have a coil resistance of about 2 ohms.