Laser scanners have become a bit cheaper (and smaller) in the past few years (Thanks, DARPA Grand Challenge & Urban Challenge). Neato Robotics has developed a

Laser scanners have become a bit cheaper (and smaller) in the past few years (Thanks, DARPA Grand Challenge & Urban Challenge). Neato Robotics has developed a planar scanner that costs $30 to build--It's on their robot vacuum. See "A low-cost laser distance sensor", http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4543666&tag=1 http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4543666...