DaveC1 wrote:
If you go to: http://www.uglyhedgehog.com/t-534221-1.html
there is a reference to another URL with the build information for the trigger and a detailed theory of operation of the unit.
But briefly, the sensing element is a photodarlington transistor, the signal from there goes through a number of gain blocks, filters, peak hold circuit, and finally uses a relay as a contact closure to trip the camera shutter.
I'll dig a little deeper. I thought that the only solution was being extremely lucky or doing a still capture from a video. I could have captured some great shots in Colorado but I was busy trying to find shelter. Florida might be #1 in the number of strikes but they can't compete with the intensity of a Rockies thunderstorm that catches you above treeline.