J-M-L:
What does 15 laser in series mean?I think you would be better off with just 1 PIR sensor that gives you volume coverage detection rather than a thin line of light which will be highly sensitive to current lighting conditions unless you have really really strong lasers which then is possibly a legal issue depending where you live.
Im not really even sure what a PIR sensor really is....Just did a quick google search. Something about detecting heat or something? Which that would be nifty to use. But still would need 1 for eash side window area, 1 for the rear window area, and 1 for each door(2 door) So 5 total.
As far as lasers, im not sure what ones im going to use yet. I mean I do have some very powerful handheld lasers. Can be seen for a few miles very clearly and burn things easily. No legal issue with them where I live. As long as you dont use them illegally.