> (Sort of like how you can find the height of a building with a barameter.)

Well this is the kind of things where you learn the most with a lot of fun.
If you can build a range finder with laser pointers you have got to have a
pretty high skill!

Anyway, range finders have their advantages. You don't have to walk the
distance you're going to measure (like with a ruler). And you get an
electronic signal that can be evaluated using some kind of microprozessor.
I'm using a range finder to measure the distance to "dynamic" targets when
I'm shooting with my air rifle.

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