While the PR2 is beyond the reach of a hobbyist, the company's meta operating system ROS (http://www.ros.org http://www.ros.org) can be installed on any persona

While the PR2 is beyond the reach of a hobbyist, the company's meta operating system ROS (http://www.ros.org http://www.ros.org) can be installed on any personal computer for free. You can run the same navigation, vision recognition, and other algorithms the PR2 uses (among other robots) on most capable computers. And with the new AVR bridge (http://www.ros.org/wiki/avr_bridge http://www.ros.org/wiki/avr_bridge), you can even interface the "hobbyist" Arduino with the OS.