In my pinhole forays, I found that fast films called for too short an exposure in bright outdoor scenes to time reliably with a human-powered shutter (a true digital shutter -- operated by thumb and forefinger ). So I have gone toward the slower films to get exposures out towards 4 or 5 seconds with my gear. There has also been some suggestions that high reciprocity failure in some of the fast films actually results in longer exposures than some of the better behaved slower films like ACROS 100.
I've been fiddling with the idea of an electronically timed shutter activating a small solenoid. The difficulty seems to be availability to timers with short(1/30-1/2sec) ranges. I found one source that could provide custom timing in that range for about an extra $100 + the timer($50)
The other thing is operating voltage every thing seems to be 9-12-24V