And your idea would probably just not work, sorry to say. Too many environmental factors which would mess with your setup, as you mentioned... Your best bet is either an IR or US sensor setup... I prefer US, but others may disagree.
And your idea would probably just not work, sorry to say. Too many environmental factors which would mess with your setup, as you mentioned... Your best bet is either an IR or US sensor setup... I prefer US, but others may disagree.