MQTT Sensor Onboarding¶

This guide shows how to connect MQTT topics to Spaxiom using the MQTTSensor adaptor.

1. Install Dependencies¶

pip install spaxiom
pip install paho-mqtt

2. Confirm Broker Access¶

You should know:

Broker host (e.g. localhost or IP)
Port (default 1883)
Topic (e.g. sensors/temperature)
Credentials (optional)

3. Create a Sensor in Python¶

from spaxiom import MQTTSensor, Condition, on

temp = MQTTSensor(
    name="temp_mqtt",
    broker_host="localhost",
    broker_port=1883,
    topic="sensors/temperature",
    username="user",
    password="pass",
)

temp_high = Condition(lambda: temp.read() > 28.0)

@on(temp_high)
def alert_high_temp():
    print("Temperature exceeded 28°C")

4. Start the Runtime¶

spax run ./mqtt_demo.py --poll-ms 200

5. Verify Payload Format¶

MQTTSensor expects numeric payloads. If you publish JSON, publish a numeric value only or convert to a number before publishing.

Example payloads that work:

22.4
17
0.82

6. Edge API Registration (Optional)¶

curl -X POST http://localhost:8080/api/sensors \
  -H "Content-Type: application/json" \
  -d '{
    "name": "temp_mqtt",
    "sensor_type": "mqtt",
    "location": [0, 0, 0],
    "config": {
      "broker": "localhost",
      "port": 1883,
      "topic": "sensors/temperature"
    },
    "enabled": true
  }'

Troubleshooting¶

ImportError: pip install paho-mqtt
No values received: Verify topic, broker host, and firewall
Non-numeric payload: Update publisher to send numeric values