Thank you so much
!!!!! You're welcome. I assume you mean that it works with the 270 Ohm resistor and your only problem now is the one outlined below. Is that correct?
I just had an epiphany. Originally I thought that there should be no current between the collector and the emitter. Rather, what I now believe is happening is that when the opto is turned on, that current either goes away, or becomes very low for an extremely brief second. When the current returns to the neccessary current to fire the flash (i.e., opto is off) then the flash fires.
That does not make much sense to me.
Is this correct do you think? Either way it works now, but I'd still like to understand what's going on.
Here's a link to a page with a diagram of what I'm doing. Forget about all the stuff below the push button, as I'm not using those parts.
High Speed Photography - Let Arduino turn The Lights Off For You | DIYPhotography.net