is it really that hard to time the exposure manually, especially with digital where misses don't cost you anything?
When I tried (it was about the first thing I did with an arduino, I'll return to it at some point soon) I found a digital camera handy to check things were working, setting the delay between trigger and flash, finding a decent angle, etc. Next time I try it I'll be using a digital camera to start with then switching to a proper film SLR.