esp32-doorbell

Use an esp32 with a CT103C to make a doorbell smarter

You will need to make a file network_conn.h with contents similar to

const char* ssid       = "your-ssid";
const char* password   = "your-wpa-passwd";
const char* mqttServer = "your-MQTT-server";
const int mqttPort     = 1883;

in order to provide details of your network and MQTT server

The MQTT channels are based off the word "doorbell" and the last 6 digits of the MAC

 e.g  doorbell/123456/front_door
 e.g  doorbell/123456/back_door

Uses PubSubClient library

GPL2.0 or later. See GPL LICENSE file for details. Original code by Stephen Harris, Sep 2021

How this works

A normal doorbell has a simple circuit that's basically an AC power (maybe 16V) supply connected to a button connected to a solenoid that throws a hammer to hit a chime. When you press the button the circuit is closed and the chime rings

Now this can't be read directly by Arduino/ESP8266/ESP32 type devices because of the 16V AC supply.

But what we can do is detect the current flow with a simple current sensor. With a device like a CT103C you can run one of the cables through the sensor. It outputs a signal proportional to the current, and this can be read by an analog port.

The ones I have looks a lot like this:

Many homes have two doorbells (front and back). These are effectively two different circuits, so you need two sensors and two ADC ports. If you also need WiFi that pretty much means an ESP32 (or an Arduino with a WiFi hat). I went down the ESP32 route.

This sketch also has "hidden" hooks for OTA updates via HTTP, based off my example sketch but minor modifications for ESP32 (since the libraries are different)

When a button is pressed a message is sent to the MQTT server

The MQTT channels are based off the word "doorbell" and the last 6 digits of the MAC eg doorbell/123456/front_door doorbell/123456/back_door

This message can be used as a trigger for HomeAssistant, for example.

These two automation entries read directly from the MQTT topic and don't need any sensor or switch entries created.

- alias: Back Doorbell
  initial_state: true
  trigger:
    - platform: mqtt
      topic: doorbell/123456/back_doorbell
      payload: 'pressed'
  action:
    ....

- alias: Front Doorbell
  initial_state: true
  trigger:
    - platform: mqtt
      topic: doorbell/123456/front_doorbell
      payload: 'pressed'
  action:
    ....

You could flash lights (helpful for deaf people), alert your phone (if you're out of home), popup a message on a smart TV...

In the Logbook you'll see entries such as

Back Doorbell has been triggered by mqtt topic doorbell/123456/back_doorbell
6:59:19 PM - 

You now have a log of every time your doorbell was pressed!