esphome-entry

A custom box to:

• detect if someone rings on my analog doorbell
• trigger a visual doorbell
• integrate with HomeAssistant

(You can also use the Status LED of the ESP32 board as a proper light in HomeAssistant in case you want to use it as a notification or something.)

Building the Hardware

Schematic

• The idea here is that we use the sound detector to trigger an event for HomeAssistant when it's loud enough (our primary audible doorbell rings)
• This also triggers the remote of a secondary (visual) doorbell (a cheap wireless doorbell set with two LED units/wall warts)
• The remote runs from a 12 V battery (A23), therefore the optocoupler instead of hooking us directly into it. The optocoupler's output is just connected to the two sides of the push button of the remote.
• Our ESP32 and sound sensor are powered by the ESP32 board's 3.3 V regulator. That regulator is powered by 5 V from the USB-C port.

Sound Sensor

We're using one of these sound sensors which use an LM393 comparator for threshold detection:

Reverse-engineered schematic from that (LEDs and supply omitted):

It's basically just an amplifier for the electret microphone and the comparator compares that amplified voltage to the reference voltage level set by the potentiometer. The output (OUT) signal is driven low when suffiently loud sound is detected, otherwise it's driven high. The green LED near the output lights when OUT is low. (The other LED is just always on and I removed it later to save power.)

Building the Software

Install Dependencies

$ pipx install esphome

Configuration

# add your secrets
$ cp -i ./secrets.example.yaml secrets.yaml
$ vim ./secrets.yaml

Compile + Flash

$ esphome run esphome.yaml

Configuration

For initial configuration, you can use the fallback WiFi AP, improv_serial, or just hard-code your WiFi based on secrets.default.yaml.

Fallback AP

You can connect to the fallback AP configured in secrets.yaml and set your proper WiFi credentials using the Web UI at port 80 of the gateway IP that you get via DHCP when connecting.

NOTE: For prebuilt GitHub releases this feature is deactivated, or we would need to include a default password. Since ESPHome's captive_portal component seems to be triggered everytime the default WiFi connection is lost, I guess this would be otherwise insecure.

HomeAssistant

This is plug & play with ESPHome's HomeAssistant integration. If the sensor is not auto-detected, just lookup its IP (e.g. from your router) and configure it manually.

Development

# install pre-commit python package
$ pipx install pre-commit

# install git commit hook in this repository
$ pre-commit install

# (optional) lint + fix all files in this repo
$ pre-commit run --all-files

Troubleshooting

• If your doorbell remote isn't triggered reliably, play with the switch.on_turn_on delay parameter to vary how long the button is "pressed".

Licenses

Schematics: CERN-OHL-S-2.0

Everything else (except .pdfs): GPL-3.0-only