RPi MQTT Monitor for OpenMower and Home Assistant

This repository contains a service that monitors Raspberry Pi device and sends various metrics to the MQTT broker. It is designed to be run on an OpenMower mower and metrics are auto discovered by Home Assistant.

Note

This project is very much inspired by rpi-mqtt-monitor and my previous attempt of running it on the OpenMower rpi-mqtt-monitor-docker.

Usage

Running on the OpenMower

Copy the rpimon.service file to /etc/systemd/system/ on your OpenMower.

Then enable and start the service:

sudo systemctl enable rpimon.service
sudo systemctl start rpimon.service

This will start publishing configured sensor values to OpenMower MQTT broker:

You can also check the logs of the service to troubleshoot if needed:

sudo podman logs -f rpimon

Configuring Home Assistant MQTT bridge

Home Assistant discovery messages are published together with sensor messages. So the only thing you need to do is to configure the MQTT bridge.

1. Go to Mosquitto add-on configuration page: Settings --> Addons --> Mosquitto broker --> Configuration

2. Enable configuration customization by adding the following to the Customize field:

   active: true
   folder: mosquitto

3. Add the following configuration to /share/mosquitto/openmower.conf file on your HA machine:

   connection openmower-to-homeassistant
   address openmower.local:1883
   bridge_protocol_version mqttv50
   topic # in 0 rpimon/ rpimon/
   topic # in 0 homeassistant/ homeassistant/
   

4. This will forward all monitoring and discovery messages from OpenMower to Home Assistant. Restart the MQTT add-on and you will see a new device under MQTT integration.

   

Configuration details

There are a couple of configuration options that can be set in the rpimon.service file as environment variables.

Environment Variable	Default value	Description
RPIMON_TICK	5 seconds	Interval between sensor values are sent to MQTT
RPIMON_MQTT_HOST	localhost	MQTT broker host
RPIMON_MQTT_PORT	1883	MQTT broker port
RPIMON_TOPIC_PREFIX	rpimon	MQTT topic prefix
RPIMON_WIRELESS_DEVICE	wlan0	Wireless device to monitor
RPIMON_MAC_FRIENDLY_NAMES	empty	User friendly names for MAC addresses

RPIMON_TOPIC_PREFIX

Controls the prefix used in the MQTT topics for the Home Assistant discovery and sensor messages. For example, with the default prefix value, the following topic names will be used for wifi_bssid sensor:

• discovery: homeassistant/sensor/rpimon/openmower_wifi_bssid/config
• sensor state: rpimon/openmower/wifi_bssid

RPIMON_MAC_FRIENDLY_NAMES

This environment variable allows to map AP station MAC addresses to user friendly names. It needs to be a string where each entry is separated by a comma and each entry is MAC address and its friendly name separated by an equals sign. For example: 00:11:22:33:44:55=Kitchen,66:77:88:99:AA:BB=Living Room

Sensor details

Most of the sensors are self-explanatory. However a couple of sensors need some extra mention.

binary_sensor.openmower_wifi_bssid

This sensor is used to monitor the WiFi BSSID of the OpenMower WiFi connection. It is especially useful when you have multiple access points with the same SSID and want to track which one your OpenMower is connected to.

This sensor value if always ON. Only the friendly_name changes with the value of the BSSID. This is designed such way for the Home Assistant Prometheus integration. It only exports certain sensor types and only if the sensor has numerical value. However, lucky to us, it also exports friendly_name as a label.

homeassistant_binary_sensor_state{
    domain="binary_sensor",
    entity="binary_sensor.openmower_wifi_bssid",
    friendly_name="openmower 3C:28:6D:6C:F9:00",
    instance="hassio.local:8123",
    job="home-assistant"
}

Here the friendly_name also is prefixed with openmower - HA device name. This is done automatically in HA and I was not able to find how to turn it off.

Now we can use Prometheus query homeassistant_entity_available{entity="binary_sensor.openmower_wifi_bssid"} and a Rename fields by regex transformation with Match argument .*friendly_name="openmower (.*)", instance.* and Replace argument $1 to get the following graph:

Here we also use RPIMON_MAC_FRIENDLY_NAMES to convert MAC addresses to more friendlier names.

sensor.openmower_ap_strength_...

These are sensors created for every BSSID that the OpenMower sees which is on the same SSID as the active WiFi connection. entity_id of these sensors end with a BSSID value with the : removed.

These are useful to track if your WiFi network AP placement is optimally used.