TransitTag IoT Dashboard

Real-time IoT dashboard that bridges MQTT messages from TransitTag devices to a browser via WebSocket, with optional InfluxDB + Grafana time-series visualization.

TransitTag Device  →  MQTT Broker  →  C Server (bridge + HTTP)  →  Browser Dashboard
                                           ↓
                                      InfluxDB  →  Grafana

Features

• Live dashboard — device status, GPS, WiFi clients, RFID scans, message log
• MQTT → WebSocket bridge — single C binary, no runtime dependencies
• Dynamic subscriptions — subscribe/unsubscribe to MQTT topics from the browser
• Time-series storage — optional InfluxDB integration for historical data
• Grafana dashboards — pre-provisioned dashboards for device metrics

Prerequisites

# Ubuntu/Debian
sudo apt install libmosquitto-dev libwebsockets-dev cmake build-essential

# Optional: for InfluxDB support
sudo apt install libcurl4-openssl-dev

# Optional: for Grafana visualization
docker and docker compose

Quick Start

# Build
cmake -B build && cmake --build build

# Configure
cp .env.example .env
# Edit .env with your credentials

# Run dashboard
./build/mqtt_dashboard <mqtt_username> <mqtt_password>

# Open http://localhost:8080

InfluxDB + Grafana (optional)

# Source your .env for the dashboard process
export $(grep -v '^#' .env | xargs)

# Start InfluxDB and Grafana
docker compose up -d

# Run dashboard with InfluxDB enabled
./build/mqtt_dashboard <mqtt_username> <mqtt_password>

# Grafana: http://localhost:3000
# InfluxDB: http://localhost:8086

Architecture

The server (src/main.c) runs a single-threaded event loop combining:

• libmosquitto — MQTT client subscribing to the broker
• libwebsockets — HTTP file server (www/) + WebSocket push to browsers
• libcurl (optional) — writes measurements to InfluxDB v2 line protocol

The browser client (www/app.js) connects via WebSocket to /ws, receives MQTT messages wrapped in {topic, payload, receivedAt} envelopes, and routes them by topic type (heartbeat, wifi, rfid, login) to update the dashboard panels.

MQTT Topics

/topic/transittag/heartbeat/<imei>   — GPS, battery, GSM, speed, movement
/topic/transittag/wifi/<imei>        — WiFi AP status + connected clients
/topic/transittag/rfid/<imei>        — RFID card scans
/topic/transittag/login/<imei>       — Device online/offline events

License

MIT