This part is a piece of a larger project for a US decora style scene controller in-wall switch. the piece is designed to mate the power supply board to the main controller board with some material to act as a separator from the high voltage side of the PSU and the under pins of the arduino pro mini.
The power supply board was created on the EasyEDA website with their online PCB design tools. the power supply board can be found here https://easyeda.com/dbemowsk/Scene_controller_power_supply-12a5db3b06db4427981fb1a3ddc9b501 and the main controller board can be found here https://easyeda.com/dbemowsk/in_wall_scene_controller-8bde3dc023404d539e822c2d0e7ab3b3 .
I have a keypad board that is also part of this project and is designed to mount in the faceplate and stack on top of the controller board. the switch board is designed so that it can be assembled into any one of a number of switch configurations to suit your needs. Check my thingiverse designs page for 3D designs of different switches that work with this board. The entire assembly is designed to fit a medium depth single gang wall box.
This is a work in progress, so things here may change.