Thanks everyone for all the answers to my previous questions. My photo
circuit is mostly done. Done in the fact that it works. It could probably
use much improvement, but it works. I built it on a bread board and mounted
it in a hard plastic VHS tape case. (Had to use a razor blade to cut off the
inside ring for the video tape.) Those actually make reasonably nice project
cases, and the transluscent ones even allow one to easily see indicator LEDs
without having to drill holes for them. But I worry that they kind of
plastic that the transluscent ones are made from may be static prone. Anyone
know?

I have rediscovered how useful those 555 timers are.

Anyway, thanks again.
Henry