🚀 go-pugleaf

I need a system that measures distances for some homebrew robotics projects.
Though I don't have the specs on hand, as I recall, the Polaroid "system"
doesn't measure down to the 1/8th of an inch, and it has a "large" frontal
area to boot. I would like to be able to measure to an 1/8th of an inch
accuracy or greater, over a distance of 1/4" (or so) to 30 feet. Also, and
more importantly, to have it be a narrow beam (1/4"?) width spread at the
maximum distance. This is so that I will be able to get ranges at specific
spots, and to be able to "see" smaller than wall size objects. All of the 
above measurements are rough, but hopefully, indicative of what I would
like to achieve. Lastly, is the price of such accuracy within the realm
of a homebrew project? $500-$1000?
Thanx!
                                        - MJB -