# DSMR 2 MQTT bridge

## Introduction

This bridigng component reads Dutch Smart Meter Requirements (DSMR) telegrams and sends them to a MQTT broker using the [Homie convention](https://homieiot.github.io/). The component is written in Python and is based on the execelent work of others:

* [DSMR Parser](https://github.com/ndokter/dsmr_parser)
* [Homie4](https://github.com/mjcumming/homie4)

## Configuring the bridge

Create some environment variables (e.g. with a .env file) to specify the required settings:

```bash
PYTHONPATH="."
MQTT_HOST=<mqtt-broker-hostname>
DSMR_PORT=/dev/ttyUSB0
DSMR_PROTOCOL=V5
```

If you have forwared the raw serial signal through ser2net, you should use `DSMR_PORT=tcp://<hostname>:<port>`, e.g.:

```bash
DSMR_PORT=tcp://forwarding-pi.local:3334
```

If you use credentials to access the MQTT broker, then alsp specify:

```bash
MQTT_USERNAME=<mqtt-user>
MQTT_PASSWORD=<mqtt-password>
```

Inspect the source [`app_settings.py`](app_settings.py) to find out about the other less frequently used settings.

## Configuring ser2net

On the forwarding computer (e.g a Raspberry Pi) you need to install ser2net:

```bash
sudo apt upgrade && sudo apt install ser2net
```

Then edit the configurion file `/etc/ser2net.yaml` and add

```yaml
connection: &Dsmr
    accepter: tcp,3334
    connector: serialdev,
      /dev/ttyUSB0,
      115200n81, local
```

![Works with Homie](https://homieiot.github.io/img/works-with-homie.png)