Hello,
thinking about resurrecting this thread a bit. I've been using Hasselblad 205fcc with Phase One P20 and P45+ for some time now and always wondered about the possibilities to use them together with FE lenses.
To my knowledge, P1 back needs 2 signals from the body/lens. 1st one is the activation signal, which is delivered by a lever protruding from the body to the back (the one which normally checks whether the film body slide is out and the film can be exposed). The second signal comes normally from the lens shutter and lasts until the shutter closure.
One can set the lens shutter to "B" on a 20X body and use the focal plane shutter instead of the leaf shutter in the lens.
That made me thinking about a device, which would deliver the signal to the back just for the duration of the time the release is pressed on the body.
Long story short, after some time tinkering with my son's 3D printer, multiple design trials and failures and a bit of soldering, I ended just with that.
The orange lever presses the trigger and after initiating the actual picture-taking sequence, it activates a micro-switch which takes care ot the 2nd signal to the back. The signal is routed to the PC sync socket on the device and then by the standard PC sync to 2.5mm jack cable to the P1 back. Everything is connected to a 3D printed Arca Swiss foot.
Appreciate this all sounds quite complicated and requires a lot of fiddling as the tolerances in the firing sequence timing are quite small. On the other hand, I can confirm after a month of using, it actually works quite well. Not always 100% but okay for me.
I certainly had a lot of fun during the process and enjoy the results.
jr