Basic electronics help needed - How to get a Pocket Wizard to trigger a Panasonic GF1

Tobers

Tobers

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Andy
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Help needed from anyone with hobby-standard electronics capability!

I'd like to trigger my Panasonic GF1 remotely using a Pocket Wizard. I have the following bits:

3x Pocket Wizard plus II
1x Panasonic GF1
1x Hahnel wired remote trigger for the GF1
various soldering bits of kit
a multimeter
no knowledge what I'm doing :-D

From my basic investigatory work, I've figured out:

- The GF1 uses the two contacts furthest from the top of the odd 4-pole 2.5mm plug to trigger the GF1 to fire the shutter
- The circuit on these two contacts is normally closed.
- A half-press on the Hahnel remote opens the circuit with a 5 ohm resistance, and focuses the camera
- A full press has a 2 ohm resistance and triggers the shutter.

So what I need is a cable to go from the Pocket Wizard to the odd 4-pole plug which, when the Pocket Wizard is fired by another Pocket Wizard, opens the circuit with a 2 ohm resistance.

Does this simply mean that I can make up a cable with a 2 ohm resistor in it that has the right pin connections? What I cant work out is what the Pocket Wizard does when it's triggered as it's too fast for my multimeter to register what happens. Does the PW just open a circuit, or is it doing something more complicated?

Ta!
 
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Hmmm...I've just made up a wire with a 2 ohm resistor in the middle of it.

In theory, connecting this to wires connected to the relevant two poles of the 2.5mm plug should trigger the GF1 to fire its shutter. But it doesn't. Have I missed something here?

Here's a picture of the Hahnel remote:

1082706833_bpAf5-L.jpg
 
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Not knowing what the Hahnel works, bnut you might also have to apply a 2 ohm (or whatever value) to another set of contacts to get the autofocus to work. The innards of the remote look like you push the button half way and one contact is made, then push all the way and that contact is still kept whilst the additional one is made. You might have to have both short circuited for it to fire.
 
Thanks - will have a look at that...

EDIT: just tried it out - seems no other contacts are affected with a half-press or a full-press. It's just the inner two. The way I'm checking this is to have the multimeter on the "resistance" setting (the ohm symbol) and I'm touching each of the contacts on the plug to each other one in sync. The only changes are to the inner two contacts when the remote button is pressed, and the resistance goes 5 ohms with a half press and 2 ohms with a full press.

I disassembled another wired remote (cheapo eBay one) for the GF1 and confirmed that the only two wires in the cable are soldered onto the inner two contacts of the 2.5mm plug.

Is it possible the camera has to "see" 5 ohms first and then 2 ohms - would it have that logic in it. Seems awfully complicated.
 
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Just decided to see if the camera was passing a current through the plug and indeed it is passing 3v on the two inner contacts of the plug. What does this mean? I guess the remote connects up the contacts to show 3v, and then as you press the button the resistors kick in somehow.

I wish I'd paid attention in physics at school!

EDIT: more info: there is 40 ohms resistance across the remote plug contacts in the "resting" state. This then drops to 5 ohms then 2 ohms as you half press then full press the button. So perhaps the camera needs to see 40 ohms first to confirm there is something connected to the remote socket.
 
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OK - so this is now becoming a record of how this GF1 remote thing works.

I've rigged up a wire with 38 ohm resistance, and another wire with 2 ohm resistance. Connecting them in series gives 40 ohms.

Connecting the 40 ohms to the two inner poles of the 2.5mm connector, then bypassing the 38 ohm resistance with another wire (giving 2 ohms) focuses the camera and triggers the shutter. So the camera clearly looks for 40 ohms to know there's a remote connected, then 2 ohms to make the shutter fire.

So what I need to do now is rig a Pocket Wizard cable to replicate this.

I'm guessing that all the pocket wizard does is make a connection. If so, I could use that connection to bypass the 38 ohms resistance and trigger the 2 ohms to fire the shutter.

Off to do some soldering...
 
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