I have a few questions for the Density folks: - How well does it handle people walking in side by side? - What about someone pushing a cart or stroller? - Ca

I have a few questions for the Density folks: - How well does it handle people walking in side by side? - What about someone pushing a cart or stroller? - Can it tell if someone is walking in or out? - How far does the laser reach? Would I need two sensors if I had a double or triple wide door? - I assume these are battery powered? How long do they last?