About this 3D model

I recently got the "4WD Arduino Compatible Mobile Platform" and was looking to put some sensors on it. I had some PING))) distance sensors that I want to put to use, so off to FreeCAD we go. A few hours and a lot of fiddling. This model went nearly from print to picture. The PING slotted right in. The mounting holes needed drilling to the proper size. For me, a few twists by hand with the dremel and 3mm bit. Holes on the base are spaced to allow mounting in the appropriate spots on the platform, and to firmly mount the sensor.