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DC MQTT Pipeline

Overview

This section demonstrates how Node-RED, Grafana, and InfluxDB integrate within the Direct-Connect (DC) Node data pipeline.
We’ll start by exploring a test node setup, running a sensor script, and understanding how MQTT communication fits into the overall workflow.

Step 1: Log In and Access the Test Node

  1. Log in to the test node.

  2. Open a new shell and navigate to the GitHub repository folder:

    su teamlary
cd /home/teamlary/gitHubRepos/iotSystemsGuide/DCNodes/firmware/xu4Mqtt/

The DCNodes directory contains a representative codebase for operating Direct-Connect (DC) Nodes on single-board computers (SBCs).

Inspect the file bme280Reader.py — this script provides a basic implementation of a climate sensor (BME280) used in live deployments.

Step 2: Run the Test Sensor Script

Execute the script:

python3 bme280Reader.py

Then, log in to InfluxDB to verify if recent data (from the last 5 minutes) is available.

Step 3: Check Data in InfluxDB

  1. Visit: http://mdash.circ.utdallas.edu:8086/
  2. Log in using your credentials.
  3. Navigate to the sharedAirDFW bucket.
  4. Filter by:
    • Node Name
    • Sensor ID

You can identify the correct node name using the id_lookup.csv file.

Influx Dashboard 1 Influx Dashboard 2 Influx Dashboard 3

⚠️ Since MQTT is not yet activated on the node, you will not see any live data at this stage.

Step 4: Enable MQTT on the Node

Open the mintsSensorReader file and uncomment the final two lines in the sensorFinisher() function, then rerun bme280Reader.py.

def sensorFinisher(dateTime, sensorName, sensorDictionary):
    print("-----------------------------------")
    print("-------- Sensor Finisher ----------")
    print(sensorName)
    writePath = getWritePath(sensorName, dateTime)
    exists = directoryCheck(writePath)
    writeCSV2(writePath, sensorDictionary, exists)
    print(writePath)

    if(latestOn):
       mL.writeJSONLatest(sensorDictionary, sensorName)
    if(mqttOn):
       mL.writeMQTTLatest(sensorDictionary, sensorName)

Once MQTT is enabled, you should begin seeing live data arriving from the node.
However, this will only work if the node is already registered in the workflow. Next, we’ll simulate a scenario where the node is brand new.

Step 5: Simulate a New Node Registration

To simulate adding a new node, open mintsDefinitions.py and comment out line 30 as shown below:

# nodeID = findMacAddress()
nodeID = "a0b1c2d3e4f5g6"

Then rerun:

python3 bme280Reader.py

Check again in InfluxDB for data under this new node ID.

You’ll notice no data appears — this is expected.
The node hasn’t yet been registered in the system.
The following section describes how to register new nodes so their data is accepted by the InfluxDB workflow.