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MQTT Configuration

MQTT broker setup and message routing.

Overview​

MQTT (Message Queuing Telemetry Transport) is used to:

  • Bridge LoRa messages to IP network
  • Enable Node-RED to process messages
  • Route Claude responses back to mesh

Mosquitto Broker​

Installation (already done on RPi5)​

sudo apt install mosquitto mosquitto-clients
sudo systemctl enable mosquitto
sudo systemctl start mosquitto

Configuration File​

/etc/mosquitto/mosquitto.conf:

listener 1883
allow_anonymous true

Verify service​

sudo systemctl status mosquitto

Test connection​

# Terminal 1: Subscribe
mosquitto_sub -h 192.168.68.127 -t "test/#" -v

# Terminal 2: Publish
mosquitto_pub -h 192.168.68.127 -t "test/hello" -m "Hello World"

Topic Structure​

Meshtastic topics​

TopicDirectionPurpose
meshtastic/2/json/LongFast/!69d01ebcReceiveMessages from mesh
meshtastic/2/json/LongFast/!69d01ebc/sendtextSendMessages to mesh

Subscribe to all Meshtastic traffic​

mosquitto_sub -h 192.168.68.127 -t "meshtastic/#" -v

Message Format​

Received message (JSON)​

{
  "channel": 0,
  "from": 2846474973,
  "id": 123456789,
  "payload": {
    "text": "@claude What is LoRa?"
  },
  "sender": "!a9b8c7d6",
  "timestamp": 1699900000,
  "to": 4294967295,
  "type": "text"
}

Send message​

mosquitto_pub -h 192.168.68.127 \
  -t "meshtastic/2/json/LongFast/!69d01ebc/sendtext" \
  -m "Hello from MQTT"

Node-RED Integration​

MQTT In Node​

  • Server: 192.168.68.127:1883
  • Topic: meshtastic/2/json/LongFast/!69d01ebc
  • QoS: 0

MQTT Out Node​

  • Server: 192.168.68.127:1883
  • Topic: meshtastic/2/json/LongFast/!69d01ebc/sendtext
  • QoS: 0

Troubleshooting​

Connection refused​

# Check if Mosquitto is running
sudo systemctl status mosquitto

# Check port
netstat -tlnp | grep 1883

# Check firewall
sudo ufw status

No messages​

# Subscribe to everything
mosquitto_sub -h 192.168.68.127 -t "#" -v

# Check Meshtastic MQTT settings
meshtastic --get mqtt

Messages not reaching mesh​

  1. Verify topic is correct
  2. Check Meshtastic service is running
  3. Verify MQTT settings in Meshtastic