Home-made wireless P-TTL triggers?


Link Posted 17/11/2012 - 22:44
Hi all,
I know wireless triggers have been discussed here on the forum before, but I haven't found exactly what I'm looking for.
Although I've had basically zero experience with wireless flash so far, I've been thinking and reading about it and it bothers me that there are virtually no wireless P-TTL flash triggers available for Pentax at the moment (ok, there are those Aokatec ones - but how long will the camera battery last if you fire a flash every time?) So I was thinking: would it be so difficult to modify p-ttl triggers designed for other brands? And if modified, do you think they would actually work? Like, there are i-ttl triggers for Nikon, for example. The pin layout looks VERY similar to Pentax flashes, but ok, there must be small differences and the pins of a Pentax flash probably wouldn't touch the pins on a Nikon receiver. BUT, what if I took a transmitter and receiver for Nikon and changed the hot-shoe for a Pentax one? Re-soldered it? Do you think it might work? Is there any special Pentax 'protocol', any sequence of signals, that might prevent this from working? My thinking is, if the number of pins is the same, what the heck does it matter what sequence of signals Nikon or Pentax uses? All that the transmitter does is send signals, and all that the receiver does is receive signals, right? So if I could achieve correct contact between the hot-shoe and the camera/flash, it should work, shouldn't it?
English is not my mother tongue, but I did my best to make myself clear and hope you understand what I mean Your opinions are appreciated, thanks in advance.


Link Posted 17/11/2012 - 23:55
I see what your sayin. If we number the pins say, and on the n+k*n pin 1 recieves a signal voltage of 3.5v to area 1 of the flash how do we know that pin 1 on the body will be sending the correct voltage to the correct area? ??

We would need to know exactly what each pin on the body is sending to each pin on the flash, pin 1 may be sending the signal pin 3 needs??

It's late and Ive had a fair amount of beer
One day you'll find, 10yrs have got behind you.


Link Posted 18/11/2012 - 08:43
Hmmm... you might be right, Daz. And I'm not capable of actually measuring the voltages and figuring out exactly which pin sends what signal. But still, there must be tons of more experienced Pentax users around the world and it amazes me that no one has figured it out yet. Well, there must be some catch in it, otherwise someone else would have done it a long time ago.


Link Posted 18/11/2012 - 09:07
I've looked into it myself. I'd love to have full true wireless P-TTL that does not require the on camera flash to fire, why and for what I don't know, but it seems like a simple thing to achieve.
I was a dissapointed to find the built in wireless flash system didn't do this but hey ho there ya go
One day you'll find, 10yrs have got behind you.


Link Posted 20/11/2012 - 17:48
I think there might be further complications involved as even simple systems don't cross over, for example :-

I have an "ishoot" radio trigger the receiver of which has a central pin and 4 smaller pins.
I've no idea what these pins do, but they fire off a Pentax 240AZ which has 3 pins (which match the centre pin and the 2 nearest smaller pins).
The transmitter portion (the bit that fits on the camera hot shoe) only has a single pin so can only react to a voltage presence/short.

On my K10D and a K5 the flash is fired sucessfully without any feedback.

BUT, and here's the crux, my sons camera which is a Canon when fitted with the transmitter will not fire the Pentax flash gun.

So it appears it is not simply a voltage sync but maybe a timing sync - does this make sense or help any?

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