metermon

Metermon is a dockerized rtlamr wrapper that connects to an existing rtl_tcp instance and outputs formatted messages over MQTT for consumption by other software (e.g. telegraf for storage in influxdb and display in grafana, or import into Home Assistant).

The script can be run using docker (takes care of all dependencies) or standalone. It is designed to run on Raspberry Pi or similar.

All credit for rtlamr goes to bemasher.

Usage

1. Have a MQTT broker you can connect to. I use Mosquitto.

2. Ensure you have a rtl_tcp instance that is listening for new connections. I use this docker container.

3. Run the container or script using instructions below.

4. Subscribe to the mqtt output topic, metermon/output, with the data consumer of your choice.

5. Process with your data consumer of choice. An example config for Telegraf and Home Assistant is provided.

Output format

By default, metermon outputs JSON messages to the metermon/output mqtt topic. The metermon prefix can be changed by setting the MQTT_TOPIC_PREFIX environment variable. Metermon will then send its output messages on [MQTT_TOPIC_PREFIX]/output. Note that adding a trailing / to MQTT_TOPIC_PREFIX will create an empty level.

Value of MQTT_TOPIC_PREFIX	mqtt output topic
metermon	metermon/output
sensors/meters	sensors/meters/output
sensors/meters/	sensors/meters//output

JSON keys

The JSON message has a single level with the following keys:

Key	Example	Description
Protocol	SCM	The protocol of the received message. See here for the list.
Type	Electric	The meter type of the received message, converted to generic utility type, e.g. "Electric", "Gas", or "Water". See here for mapping of numeric ERT type.
ID	29163678	The unique ID of the meter the received message originated from.
Consumption	96948.54	The current consumption value in the received message, processed into standard units (Ex.: electric meters report in 1/100 kWh, metermon divides this value by 100 to get kWh).
Unit	kWh	The unit that metermon has converted the value to. Metermon decides this by knowing the type of meter and/or the protocol.

If the METERMON_SEND_RAW environment variable is set to true, metermon will send the entire unprocessed JSON message received from rtlamr to the [MQTT_TOPIC_PREFIX]/raw topic.

If the METERMON_SEND_BY_ID environment variable is set to true, metermon will also send the processed JSON message received from rtlamr to the [MQTT_TOPIC_PREFIX]/[UNIQUE_ID_OF_METER] topic. This, combined with the use of the RTLAMR_FILTERID environment variable, can make it easier for parsing just a few meters into Home Assistant.

Status Messages

Metermon will report its status on the [MQTT_TOPIC_PREFIX]/status topic via retained messages. Metermon reports Online once it connects to the broker. Upon disconnect, the broker will report Offline.

Performance Tuning

By adjusting the RTLAMR_SYMBOLLENGTH environment variable, sample rates can be modified to reduce CPU load. See documentation of this feature here and a discussion of the potential performance impacts here.

Running via Docker

Pull the image. The latest tag has multiarch support, so it should pull the correct image for your system.

docker pull seanauff/metermon

Start the container with all default environment variables:

docker run -d seanauff/metermon

Start the container with modified environment variables:

docker run -d -e MQTT_BROKER_HOST=<host> -e RTL_TCP_SERVER=<server> seanauff/metermon

Alternativly, use docker-compose. See docker_compose.yaml

Environment Variables

Variable	Default Value	Notes
MQTT_BROKER_HOST	127.0.0.1	IP or hostname of MQTT broker
MQTT_BROKER_PORT	1883	Port of MQTT broker
MQTT_CLIENT_ID	metermon	Change this if the default is already in use by another client
MQTT_USERNAME		Username for connecting to MQTT broker when using auth. TLS not currently supported
MQTT_PASSWORD		Password for connecting to MQTT broker when using auth. TLS not currently supported
MQTT_TOPIC_PREFIX	metermon	Set the prefix to use for the MQTT topic that messages are sent to
RTL_TCP_SERVER	127.0.0.1:1234	server:port that your rtl_tcp instance is listening on
RTLAMR_MSGTYPE	all	List of message types to listen for. See rtlamr config
RTLAMR_FILTERID		List of meter IDs to look for. See rtlamr config
RTLAMR_SYMBOLLENGTH	72	Adjust sample rate by setting the length of each symbol. See rtlamr wiki
RTLAMR_UNIQUE	true	Suppress duplicate messages from each meter. See rtlamr config
METERMON_SEND_RAW	false	Set to true to enable sending the raw json from rtlamr to the [MQTT_TOPIC_PREFIX]/raw topic
METERMON_SEND_BY_ID	false	Set to true to enable sending the processed json to the [MQTT_TOPIC_PREFIX]/[UNIQUE_ID_OF_METER] topic.
METERMON_ELECTRIC_DIVISOR	100.0	Change this to correct the electricity units that your meter reports in to kWh
METERMON_WATER_DIVISOR	10.0	Change this to correct the water units that your meter reports in to gal

Troubleshooting

If you receive meter messages with rtlamr but they are not showing up in metermon, it is likely that metermon doesn't recognize the "Endpoint Type" of your meter. This can be easily fixed so please open an issue with the rtlamr output and meter type (gas, electric, water) and I can add it.

Build the image yourself

Clone the repository and build the image:

git clone https://github.com/seanauff/metermon.git
docker build -t seanauff/metermon metermon