[Ken Leedle]

You could wire a Maxbotix sonar ranger directly to your analog inputs. They are only $30 and work very well. If you want to build a laser range finder, you could do it with a laser pointer, diffraction grating, and video camera. Shine the laser though the diffraction grating and measure the distance between bright spots with the camera. This would probably require a camera with higher resolution than the CMU camera has. Just an idea. Whatever range finder you use, you will probably have to slow your robot down to navigate effectively.