First and main use I'm designing it for it to trigger my camera for a long exposure of my bike as I pass by, will be manually or wirelessly triggered to start and the laser will stop it,
Aligning nthe laser is certainly the hardest part during my test setup, but did a real world application and over the course of the 30 or so feet the beam travels it actually gets to be about 5 inches in diameter, current method of eliminating erroneous light is that pot 1M is the highest it can be, depending on the value of that it takes a certain amount of light to bring the signal low enough to trigger the digital input change
I've tried a few other methods with an opamp bu so far this seems to work best, just so long as my source is brighter than any other ambient sources