Simultaneous electronic shutter release for multiple cameras

I'm trying to trigger six Panasonic Lumix G7 cameras at once.

The trigger mechanism uses a four pole 2.5 mm plug, some resistors and two switches. With no switch closed there is 41 kilohms of resistance. To trigger the focus, you reduce that to 5 kilohms. To trigger the photograph or video start you allow 2 kilohms of resistance.

So much I learnt from this great blog post: "(Remote Shutter Control Circuit for Panasonic GH1 Digital Camera)":http://www.robotroom.com/Macro-Photography-2.html

Wired this way it triggers a single camera just fine. However, when you add additional cameras to the circuit, it doesn't work anymore. I'm guessing that the resistance is no longer correct, because now a focus trigger does nothing (I think) and a shutter release trigger makes one camera focus.

When I was 11 I was the proud owner of a DSE Funway into Electronics set. I'm afraid I've learnt nothing much since.

Any way to wire this up so that the resistance is correct for all the cameras? Ideally I could add more than 6 cameras in the future following the same method.

My fall back is independent circuits with a mechanical switch closing them all independently, but 1/100 second accuracy would be a big help here, so I'd love to do it a little more correctly.

Cheers,

Red

You can replace the two switches with the outputs of a FET or darlington opto-isolator. You will need two opto-isolator channels and three resistors for each camera. If you use a darlington opto-isolator, you might have to reduce the values of the resistors slightly as the darlington output transistors don't have an effective resistance of 0 ohms when on (like the switches). Without knowing the circuitry inside the camera it is difficult or impossible to predict what values of resistors you will need, but you could build a single unit with trim-pots for the resistors and adjust them until everything works.

You could wire all the led's on the other side of the opto-isolator, but you would end up with something much more useful if you drive them with six separate outputs from an Arduino or other microcontroller (you could do limited "bullet time" freeze frame animation). You will need a current limiting resistor in series, just like any other LED.

If you drive all the opto-isolators from a single output, you will need a basic npn or nfet switch to provide enough current to drive multiple leds from a single microcontroller pin.

V.Sambath kumar

I have designed a simple ckt using scr see if it suits your requirement.

only 2 stages are shown copy the 2nd stage for all the 4 cameras. pl give me the feed back and if ok .pl review my rating. aft er the full operation is over reset the system
using switch s1.


good luck.