Without spending a lot of money, I wanted to wake up to already brewed coffee. Here's how to make a smart dumb coffee machine using an ESP8266, HomeBridge and Google Assistant

Materials needed:

1. Dumb coffee machine
2. 1 x ESP8266
3. 1 x 5V relay
4. 1 x 3.3V PSU

You can start the coffee machine by pressing the start button so it's obvious that inside it there's a circuit that has to be closed.

After opening it up and finding the main control board, I discovered I had to close the circuit between the red and blue contacts.

I soldered two wires to a contact on each side, tested

and put the circuit board back in its place.

I connected the wires to a relay (a transistor would have worked just fine)

Used a cheap (as in expensive and low-quality) 3.3V PSU that needed an additional capacitor to power up the ESP8266 properly

Tested the whole thing again, split the power cord such that I could power everything up, tucked the whole thing in an empty spot on the inside and closed everything up.

Set up a stateless switch in HomeBridge pointing to the ESP8266, refreshed my Google Home connection and that was it.

Using the Google Clock app, the coffee machine starts automatically when my alarm rings in the morning.