German aerospace engineer Andreas Haeuser has been devoting his knowledge and talent to designing ingenious inventions that can be easily and inexpensively built by anyone with a 3D printer. His latest, the Ardumower, is an automated robotic lawnmower - sort of like a Roomba for the lawn - consisting of little more than an Arduino board, a rechargeable battery, and 46 3D printed parts. He also offers a comprehensive, step-by-step instruction manual along with the STL files. Read more at 3DPrint.com: http://3dprint.com/120980/3d-printed-lawnmower/