/ams-han-port

Read HAN port on Norwegian AMS Smart Meters

Primary LanguageC

ams-han-port

Read HAN port on Norwegian AMS Smart Meters

This is a fork of https://github.com/per-erik-nordbo/ams-han-port, with added MQTT functionality. It is in a very early stage, but the MQTT sending works. Tested on a Raspberry Pi.

I cannot promise any development, as long as it works for me and nobody else asks for anything.

Main changes to the parent project:

New files

  • han-reader.c reimplements the HAN-reading functionality from read.c, in a more reusable way
    • in the long run, the original serial-output code could be rewritten to use this
  • han-mqtt.c implements the MQTT functionality
  • han2mqtt.c is the main driver
    • currently a bare minimum, no command-line options etc.

Future possibilities

There are two main options:

  • keep han2mqtt as a separate binary, with only MQTT functionality
  • add the MQTT with the original binary, as one of possible outputs
    • note that this option would imply dependence on a MQTT library for all users

Independent on this, the MQTT part needs the following:

  • some way of controlling the parameters: either command-line parameters, or a config file
  • possibly a more "standard" format of the MQTT messages, for example using the Homie format

Dependencies

The code requires Mosquitto MQTT library. In Debian, this can be installed using apt install libmosquitto-dev.

Building han2mqtt

  • Using the Makefile

    1. edit the SERIAL_PORT and MQTT_SERVER values in the han2mqtt line in the Makefile
    2. run make han2mqtt

  • Direct gcc command:

    • run gcc -Wall -Wextra -O2 -D SERIAL_PORT='"<SERIAL_PORT>"' -D MQTT_SERVER='"<MQTT_SERVER>"' han2mqtt.c han-mqtt.c han-reader.c rs232.c aes.c -lmosquitto -lm -o han2mqtt
    • on Raspberry Pi with UART adapter, the SERIAL_PORT tends to be /dev/ttyUSB0
    • at the moment, the MQTT broker port is hard-coded in han2mqtt.c

Make it a services that starts on boot

This assumes a linux system with systemd (almost any modern linux).

  • As a root (sudo), create /etc/systemd/system/ams-han.service with the following content:

     [Unit]
 Description=ams-han
 After=network.target
 
 [Service]
 ExecStart=/opt/ams-han/han2mqtt
 WorkingDirectory=/opt/ams-han
 StandardOutput=inherit
 StandardError=inherit
 Restart=always
 User=pi
 
 [Install]
 WantedBy=multi-user.target
    • replace /opt/ams-han by the path to the code and pi by your user name
    • make sure that the user has access to the folder

  • Run sudo systemctl daemon-reload to refresh the service list

  • Run sudo systemctl start ams-han.service

  • Run sudo systemctl status ams-han.service to check everything is OK

  • If everything looks OK, enable the service: sudo systemctl enable ams-han.service

At any later point, you can see the current output using journalctl -u ams-han -f