About this 3D model

This thing is a simple openscad model of the ubiquitous optical end stop module. Hopefully this will be useful to someone. Note: there is an electronics design problem with this type of Opto Endstop sold on eBay. The reason is explained here http://forums.robo3dprinter.com/index.php?threads/improved-opto-endstop-needs-some-improvement.3035/