This is a very simple application to forward readings from electricity meters to MQTT. The app connects to a serial interface, assumes readouts according to IEC 62056-21 and sends the parsed message to an MQTT broker. The idea is to consume these messages in home automation setups such as Home Assistant or Node-RED.
The app was written for the HAN port in mind but can just as well be used with other interfaces outputting data according to IEC 62056-21 such as IR interfaces.
NOTE
This app does not request data from the source but assumes that data will be sent on a regular interval. For HAN / P1, data is sent every 5-10 seconds if PIN 2 (Data request) is high
Ensure you are running at least node version 12.
npm install -g han-mqtt
HAN_MQTT_CONFIG=./config.yaml han-mqtt
sudo docker run -e HAN_MQTT_CONFIG=/config/config.yaml -v /home/pa/han-mqtt-config/:/config --privileged pakerfeldt/han-mqtt:latest
This assumes a directory called /home/pa/han-mqtt-config/ on the host machine which contains your config.yaml. Obviously change the host path to wherever you choose to store the config file. --privileged is needed for the container to gain access of the physical serial interface.
Perhaps the most convenient of choices. Ensure you have docker and docker-compose installed. Then create a docker-compose.yaml containing:
version: '3.2'
services:
hanmqtt:
image: pakerfeldt/han-mqtt:latest
environment:
- NODE_ENV=production
- HAN_MQTT_CONFIG=/config/config.yaml
volumes:
- /home/pa/han-mqtt-config:/config
privileged: true
restart: unless-stoppedprivileged: true is needed for the container to gain access of the physical serial interface.
Now you can build and run the image.
sudo docker-compose build hanmqtt
sudo docker-compose up -d
HAN or P1 is the name of the RJ12 port found on Swedish electricity meters and is meant to be used for local applications such as consumption metrics or load balancers. This interface uses 115200 baud rate with 8 databits, 1 stopbit and parity none. However, signal is inverted thus cannot be connected directly to a serial device unless first taken care of.
This readme won't go into details on how to accomplish this. There's already guides on how to do that. In short, you'll need a transistor and two resistors. Here's a complete BOM from electrokit if you choose to go that route:
| Item |
|---|
| BC547C TO-92 NPN 45V 100mA |
| Motstånd kolfilm 0.25W 10kohm (10k) |
| Motstånd kolfilm 0.25W 4.7kohm (4k7) |
| Experimentkort för FB01 |
| Apparatlåda FB01 grå 60x65x25mm |
| USB-serielladapter PL2303 |
You might very well find smaller circuit boards but this was the one I went for. Here's the schematics which can also be found, together with more description in Swedish, on https://www.akehedman.se/wordpress/?cat=39
