this is mostly for jacassity
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=92749
too rich for my blood even if i were rich. Ill stick with my tape measure method to get it in the ball park.
Im curious,, any reason why you linked me to that?,, maybe your thinking id make something like it dirt cheap.
when they get those laser tape measures calibrated to a tolerance way below a millimeter,, then ill probably rig something up using that.
they work on a simple prinl, the transmitter sends out a light bean. It is fully aware of the amount of voltage it takes to reach the flat surface on the far end. The light bounces back and it records the amount of energy it recieved. The electronics subtracts the first signal (transmit or TX) from the second signal (recieve or RX) and a total is energy value or voltage is left over. The distance the light traverses will create a loss in energy. The electronics will translate that into a distance in what ever range was engineered. The light bounces backwards right through itself.
just thought you would find it interesting. I just remembered the whole lazer level thing that you talked about a while ago.