The gecko model is not mine, but I cannot find the original source now (gecko_fin.stl downloaded May 2020). If it is yours, I am so sorry! If anyone can point me to it, I will update this page with appropriate credits.

I added screw holes and carved out the belly to hold the metal contacts/springs and circuit board of my old nutone brand lighted doorbell button.

Printing:

The gecko was printed in ABS and painted with acrylic. Supports are definitely needed as only the gecko's feet touch the printer bed. The .3mf file includes supports, variable layer height, and 2 modifiers to print 100% infill where the metal contacts/springs are inserted. 

The button is printed in Taulman T-Glase so that it is translucent and can be lit from behind. Printed at 0.1mm layer height and 100% infill.

Assembly:

Insert the button first, then the metal contacts. Note that the cavity is a little shorter than the original doorbell, so I had to trim and reshape with pliers the ends of the contacts (the 3rd picture shows a test-fit, the contacts are too long). If you don't want that hassle, scale the gecko and button slightly larger. To get the metal bits to stay in place, I briefly heated them with a soldering iron and pushed them down into the slots. Finally, screw the circuit board down over the contacts - because of the size of the cavity it will be a tight fit, and because the cavity is sloped to accommodate the gecko's slim hips, you may find the bottom screw protrudes a bit. You could switch it out with a flatter/thinner head screw. Again, scaling the model would probably solve all the issues, I didn't because I wanted to make sure it fit nicely on a single siding board.

Safety:

Turn off the power to your doorbell before removing it, and again when installing the new one! Old fashioned wired doorbells usually have a transformer (wired to the furnace) that lowers the voltage to non-lethal levels, but don't take the chance! Household electrical current will kill you. You are responsible for your own safety.