Recently, I encountered a challenge while configuring an MQTT sensor in my Home Assistant setup. The sensor was supposed to monitor the total capacity of a storage device, but it kept showing ‘unknown’ values. After some research and troubleshooting, I managed to resolve the issue and thought I’d share my experience to help others facing similar problems.
The Problem
I set up my sensor using the following configuration in configuration.yaml:
yaml
mqtt:
sensor:
- name: “S1000 total capacity”
state_topic: “storcube/reportEquip”
value_template: “{{ value_json.1234567890.totalCapacity }}”
unique_id: “s1000_total_capacity”
Despite receiving MQTT messages through MQTT Explorer, the sensor value remained ‘unknown’.
Troubleshooting Steps
- Check MQTT Broker Connection: I verified that Mosquitto was correctly installed and running on my HA environment. The MQTT integration was also properly configured.
- Inspect Message Payload: I logged the incoming MQTT message and found it contained nested JSON data. The payload looked like this:
{
“1234567890”: {
“totalPv1power”: 28,
“totalInvPower”: 0,
“list”: [
{
“equipId”: “1234567890”,
“temp”: 6,
“soc”: 30,
“capacity”: 812
}
],
“plugPower”: 0,
“totalCapacity”: 812,
“mainEquipId”: “1234567890”
}
}
- Adjust Value Template: Realizing that the value template might not correctly parse the nested JSON, I modified it to
{{ value_json.1234567890.totalCapacity }}. This change ensured the sensor correctly extracts thetotalCapacityvalue from the nested structure. - Test Configuration: After updating the configuration, I restarted the MQTT service and monitored the sensor. It now accurately displays the total capacity.
Key Takeaways
- Understand Payload Structure: Always inspect the MQTT message payload to correctly map the JSON structure in your value template.
- Use Proper Templates: Ensure your
value_templateaccurately reflects the nested structure of your MQTT messages. - Verify Connectivity: Double-check your MQTT broker and integration settings to rule out connection issues.
If you’re facing similar issues, I hope this guide helps you troubleshoot and resolve them efficiently. Happy automating!