3D Printer Power and Light Control automation module

Update June 2020
- Add PZEM-004T for energy measurement (Voltage, Current, Power)
- Software update A3

Update May 2020 ( working prototype):
- PCB version 1.1 was introduced, It corrects a small mistake in PCB layout. For the ones that build v1.0 I added a picture with the needed modification. "SKR_PWR" pin change from IO0 to IO4
- R8, R9 change from 1K to 4.7K
- software changed according to the above modification and other small adjustments descrived in SW file.

This design allows you to connect and monitors your printer from an automation system like HomeAssistant or OpenHab, or any other system that works with MQTT.
Prototype software is written for ESPHome & HA platform integration, for any other platform this must be adjusted accordingly.

Functionality:
Power control input (button):
- if the printer is OFF a short press will change the state immediately
- if the printer is ON, printer will stop only if the button is pressed more than 5seconds, nothing will happen for short pushed (countermeasure for accidental miss-use)

Power control printer input:
- This functionality is controlled by printer board
- Marlin setup --> see picture
- Slicer software --> add "M81" in the End G-code.

Light control (button):
- each short push will toggle the state.

It's compatible with the BTT Relay v2 dimension. main connectors designation and stand-alone functionality.
Parts as the power connector, relay, 5V PSU are interchangeable from BTT Relay v2

For the Light and Power inputs, you can use a mechanical pushbutton with Normal Open or you can use touch modules as TTP223 configured with option "Momentary & Active LOW".
Use this project (display case): https://www.thingiverse.com/thing:4305638

All the inputs and outputs are Active LOW.