Remote switch for HomeAssistant

Switch for switching loads such as an espresso machine (that's what I made it for). I have an automation that turns the machine on in the morning, and off 2 hours later.

Made for these parts:

• ESP32C3 supermini board such as this 

• Relay board (the 5V version)

• USB power adapter for original Apple Watch (you can probably fit a different, similar one)

• Power cable with plug at one side

• Power cable with receptacle at one side

• Wire nuts or WAGO connectors to connect the 220/120V incoming/outgoing cables

• 2 to 4 M3x6mm (shorter should also work) screws for the relay board

The holes in the case accept 6mm diameter cable, but you can just drill them larger if your cable does not fit. In fact, I drilled one of the holes in mine.

The lid is a tight fit, but it fits! Printed without supports.

IMPORTANT: If you're unsure what you're doing, do not build this yourself. Only build it if you know exactly what you are doing. High voltage and current are dangerous.

1. Print case

2. Connect 5V and GND connectors of ESP32 board to 5V power (in my case that's from the USB brick from the Apple Watch).

3. Wire up the 5V power supply (again, in my case the USB brick) to the incoming hot and neutral wire.

4. Connect incoming hot wire to NO (normally open) connector on the relay.

5. Connect incoming neutral to outgoing neutral, and incoming ground to outgoing ground.

6. Connect outgoing hot to COM (common) terminal of the relay.

7. Connect GPIO3 (that's the one I use at least) on the ESP32 board to the IN signal of the relay.

8. Connect 5V and GND from 5V power supply to the 5V power input of the relay.

9. Program the ESP32 e.g. with ESPHome; my YAML snippet for the switch is as below.

switch:
  - platform: gpio
    name: switch
    pin: GPIO3
    id: switch_gpio_1