Wattwolf

Read smart meter data* (Smart Message Language) via infrared port and send sensor-data (via MQTT) to Home Assistant.

*To be precise: "moderne Messeinrichtung", "smart meter" typically includes a gateway.

Hardware

Tested with:

• Landis Gyr E320
• Hichi IR USB reader

Configuration

Create a config file (e.g. config.toml) based on config.toml.example.

Wattwolf looks in the following order for config files:

• CLI argument --config
• Environment variable WATTWOLF_CONFIG
• Current working directory: config.toml
• global /etc/wattwolf.toml

Connection

Connect to the reader directly (e.g. device = /dev/ttyUSB0) or via TCP (e.g. socket = localhost:2000).

To connect via TCP (great for debugging/development) setup ser2net, e.g.:

connection: &con01
  accepter: tcp,localhost,2000
  connector: serialdev,/dev/ttyUSB0,9600n81
  options:
    kickolduser: true

MQTT Configuration

Setup the MQTT connection to publish discovery messages and of course the actual sensor values.

username, password and host may be overriden via environment-variables:

export MQTT_USERNAME=your_username
export MQTT_PASSWORD=your_password
export MQTT_HOST=your_host
# or use MQTT_PASSWORD_FILE for increased security, e.g. usage with systemd's `LoadCredential=`
export MQTT_PASSWORD_FILE=/run/secrets/mqtt-password

Run a development MQTT server with:

docker run -d -p 1883:1883 eclipse-mosquitto

Sensors

Sensors need to be specified by their OBIS code. All other settings are used for home assistant's auto-discovery of the sensor.

Currently supported codes:

• 1.8.0
• 2.8.0

Installation

NixOS

The flake provides a NixOS module for running wattwolf as a systemd service.

Quick example:

{
  {
  description = "Example NixOS configuration with wattwolf";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    wattwolf.url = "path:/home/elmar/Projects/wattwolf";
    # In production, use: wattwolf.url = "github:yourusername/wattwolf";

    # Optional: agenix for secret management
    # agenix.url = "github:ryantm/agenix";
  };

  outputs = { self, nixpkgs, wattwolf, ... }: {
    nixosConfigurations.example-host = nixpkgs.lib.nixosSystem {
      system = "x86_64-linux";
      modules = [
        # Import the wattwolf module
        wattwolf.nixosModules.default

        # Your configuration
        ({ config, pkgs, ... }: {
          services.wattwolf = {
            enable = true;
            mqttPasswordFile = config.age.secrets.wattwolf.path;

            connection.device = "/dev/ttyUSB0";

            mqtt = {
              host = "localhost";
              username = "wattwolf";
            };

            sensors = [
              {
                name = "consumed";
                friendlyName = "Energy Consumed";
                obis = "1.8.0";
                deviceClass = "energy";
                stateClass = "total_increasing";
              }
            ];
          };
        })
      ];
    };
  };
}

Manual Installation

Build and install manually; only libudev required (which systemd typically provides nowadays):

cargo install wattwolf --git https://github.com/elmarx/wattwolf

Building

Building for Raspberry Pi 2/Zero 2 and up

• via cross
• cross build --target=aarch64-unknown-linux-gnu

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.⏎