OpenSCAD involute parametrized gear generator
https://github.com/sadr0b0t/pd-gears
Based on project by Leemon Baird http://www.thingiverse.com/thing:5505 with some minor and major API fixes and improvements.
Installing pd-gears ( on Linux, but similar on Windows ) as a library
From within running OpenSCAD, click the Main Menu entries:
File -> Show Library Folder
OpenSCAD will open the folder with libraries that can be included in your models
From the same path as the library folder, I use open in console. Run the command:
git clone https://github.com/sadr0b0t/pd-gears.git