This Project is complete. Although I am not using it in a wall switch because it is just too large. To solve this I opened a new project here. This new board uses the new ESP01-M and is significantly smaller.

For a 3D printed box check out this.

I wanted to design a board that was simple and easy for beginners to use and required minimal soldering and no SMD parts. Yes a pre-built WeMos is more expensive than an 8266 12-E but it is simple. I also hope the simplicity of the project will help newbies get started. Again, keeping things simple I use the TASMOTA firmware. I highly recommend it.

GOAL: Safe switch with integrated AC/DC converter that can control lights from a normal 1 gang (US rectangle) box while using the pre-existing physical switch or by the the home automation software of choice. domiticz, Home Assistant, OpenHab etc... I use Home Assistant.

The power supply circuit is based on the topic here.

Simply plugin a WeMos mini and whatever shields you want or make on you own. Also header for dht22 on GPIO2 for a simple drop in temp and humidity sensor without the added bulk of a shield. I have quickly realized that stacking a WeMos and Relay makes the board too tall and would hit the switch. So I have redesigned the board to have 2 Wemos "sockets". This way the Relay can be nearly flush on one socket and the Wemos on it's own socket. This design should leave room for other options if needed.

This a work in progress and is my first PCB. I would really appreciate your feedback on my work and welcome improvements before I send to be fabricated.

Once I get the first PCB I'll solder up the pin headers and upload pictures along with instructions on how to setup Tasmota.

It would be awesome if someone could create a box. I don't have a 3-d printer to do that.