Accessorize the light switches at your home or office with this intriguing mechanism that utilizes a planetary gear! 

All parts can be 3D printed (no supports are required), and the design is fully snap together - so no glue is needed.  I printed the five gears as a unit (using the attached “Planetary Gears.stl” file), which shows their proper orientation for assembly.  But, if you'd rather print the gears independently (or are worried that a roughly .2 mm gap tolerance between the gears may cause an issue on your printer), then an individual STL is provided for each gear as well.

I designed this model from scratch for the “Office Accessories” here on Printables, but I want to call out “Engineer Dog” who showed off a similar idea several years ago.  Some notes on assembly follow:

Step #1:

Place the gears on the base plate in the orientation shown below, and note that the “planet gears” do have a right-side-up (due to the use of a double-helix gear style, which is part of what helps the entire piece hold together without needing additional brackets):

Step #2:

Place the rocker arm over its pivot point, with the long part of the arm facing towards the bottom of the plate:

Step #3:

Swing the rocker arm around and gently lift it over the top of the actuator peg on the sun gear:

Step #4:

Press the three gear nuts through the planetary gears until they snap into the other side of the base plate:

Step #5:

Unscrew your original light switch plate cover, and then attach your new planetary gear light switch cover using the same screws from the original: