IoT · Wearable · Real-Time Monitoring

Sustainable Firefighter
Monitoring Device

A real-time IoT wearable safety system that continuously monitors firefighters' physical condition, location, and environment — keeping commanders informed and firefighters safe.

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Project Overview

What is SFMD?

The Sustainable Firefighter Monitoring Device (SFMD) is a wearable IoT safety solution that collects sensor data — motion, temperature, GPS location — and transmits it over Wi-Fi to a Firebase backend. A web dashboard gives fire commanders instant, live situational awareness.

Auto Emergency Detection

Detects man-down scenarios (no movement for 30 s) and high temperature automatically — no action required from the firefighter.

Live GPS Tracking

Real-time location plotted on an interactive MapLibre GL map with a trail of the last 50 GPS positions.

Manual SOS Button

A dedicated push button lets firefighters trigger an instant distress signal that overrides all other device states.

Temperature Monitoring

DHT11 sensor reads ambient temperature every loop cycle, triggering progressive alerts as heat rises above safe thresholds.

Analytics Dashboard

Line charts, donut charts, and movement timelines provide trend analysis over a rolling 60-reading window.

Voice & Visual Alerts

Color-coded status indicators and voice alerts on the web dashboard ensure commanders never miss a critical event.

System Design

System Architecture

Three-tier architecture: wearable device → Firebase cloud backend → Next.js web dashboard. Data flows continuously over secure HTTPS.

Wearable Device

ESP32 MCU
MPU-6050 (Motion)
DHT11 (Temperature)
Neo-6M GPS
SOS Button
Buzzer + LED
Li-ion Battery

→

Firebase Backend

Realtime Database (live)
Firestore (historical)
REST API /api/data
HTTPS PUT from ESP32

→

Web Dashboard

Next.js (React)
Live Status Panel
Interactive GPS Map
Analytics & Charts
Alert & Event Log

Data Payload (ESP32 → Firebase)

{
  "temperature":   42.5,
  "total_acc":     0.98,
  "movement":      "MOVING",
  "status":        "NORMAL",
  "mpu_status":    "OK",
  "dht_status":    "OK",
  "gps_status":    "OK",
  "system_status": "OK",
  "latitude":      17.385044,
  "longitude":     78.486671,
  "timestamp":     154823
}

Components

Hardware Components

All components are mounted on the ESP32 and powered by a single Li-ion battery, keeping the device lightweight and wearable for firefighters.

#	Component	Purpose	Interface
1	ESP32	Main microcontroller — Wi-Fi, I2C, UART, GPIO	Core
2	MPU-6050	3-axis accelerometer & gyroscope — motion & fall detection	I²C
3	DHT11	Ambient temperature sensor	1-Wire
4	Neo-6M GPS	Latitude/longitude tracking	UART
5	Push Button	Manual SOS trigger (GPIO 14 input / GPIO 27 simulated GND)	GPIO
6	Buzzer	Local audible alerts for the firefighter	GPIO
7	RGB LED	Visual status indicator	GPIO
8	Li-ion Battery	Primary power source — 3.7 V–4.2 V	Power

Pin Map — ESP32

ESP32 Pin	Connected To	Notes
GPIO 21 (SDA)	MPU-6050 SDA	I²C data line
GPIO 22 (SCL)	MPU-6050 SCL	I²C clock line
GPIO 4	DHT11 Data	Single-wire; 10 kΩ pull-up to 3.3 V
GPIO 16 (RX1)	Neo-6M TX	HW Serial 1 RX
GPIO 17 (TX1)	Neo-6M RX	HW Serial 1 TX
GPIO 14	SOS Button (signal)	Active LOW, INPUT_PULLUP
GPIO 27	SOS Button (GND leg)	Driven LOW — simulated ground
GPIO 13	Buzzer (+)	Active HIGH

Firmware Logic

How It Works

The device runs a non-blocking state machine. Sensor values are read every loop iteration and the system state is updated in real time — no delay() calls that could stall GPS parsing.

Device States

Normal

All parameters within safe limits. Status LED on, buzzer off.

Warning

Potential danger detected. Alert LED on, buzzer intermittent (1 Hz).

Emergency

Critical condition. Alert LED on, buzzer continuous.

SOS

Button pressed. Overrides all other states. Continuous buzzer.

Offline

No data received by dashboard. Last known state retained.

Movement Detection — No-Motion Timer

0–10 s
MOVING

10–29 s
WARNING

≥ 30 s
EMERGENCY

The MPU-6050 computes movement = |√(Ax²+Ay²+Az²) − 1.0 g|. If movement drops below 0.03 g the no-motion timer starts. Thresholds of 10 s and 30 s trigger WARNING and EMERGENCY respectively.

Temperature Thresholds

Temperature Range	State	Buzzer Behaviour
< 25 °C	NORMAL	Silent
25 – 30 °C	NORMAL	1 ambient beep / min
30 – 35 °C	NORMAL	2 ambient beeps / min
35 – 40 °C	NORMAL	3 ambient beeps / min
> 40 °C	WARNING →	Escalates to WARNING / EMERGENCY

SOS Button Logic

Toggle Design

First press activates SOS. Second press deactivates it. Debounced at 200 ms to prevent accidental re-triggers.

Simulated Ground Trick

GPIO 27 is driven permanently LOW, acting as the button's GND leg. Eliminates a physical GND wire and simplifies the wiring harness.

Web Application

Web Dashboard

A full-featured Next.js command-center application. Connects to Firebase Realtime Database for live streaming and Firestore for historical analytics.

Live GPS Map Status Cards Temperature Trend Chart Movement Timeline Status Distribution Donut Alert & Event Log Field Units Roster Run Simulation Mode

Left Panel

Status card, battery, sensor row, comm reliability bars, and live scrollable log with timestamped events.

Center Panel

Interactive MapLibre GL map with real-time firefighter position & GPS trail. Field units roster with online/offline indicators.

Right Panel

Temperature min/avg/max badges, line chart (Recharts), movement pixel strip, and status distribution donut chart.

Stack

Technologies Used

A blend of embedded C++ firmware and a modern JavaScript web stack, unified by Firebase as the real-time data backbone.

Firmware (ESP32)

Arduino C++ ESP32 SDK WiFiClientSecure DHT11 Library MPU-6050 Library TinyGPS++ ArduinoJson

Web Dashboard

Next.js (React) Firebase RTDB Firestore MapLibre GL JS Recharts Tailwind CSS Firebase Admin SDK

Backend

API Endpoints

The Next.js server exposes a REST route for alternative HTTP-based ingestion and for writing to the Firestore historical collection.

POST /api/data

Receives sensor data from ESP32 (or any HTTP client) and stores it in Firestore.

Request Body

{
  "device_id":  "FF_001",
  "temperature": 42.5,
  "movement":   "MOVING",
  "status":     "NORMAL",
  "latitude":   17.385044,
  "longitude":  78.486671
}

Response Codes

200  { "success": true }
400  { "error": "device_id is required" }
503  { "error": "Firebase not initialized" }
500  { "error": "Internal server error" }

Transparency

Assumptions & Known Limitations

This is a functional prototype. The following constraints are acknowledged and are planned to be addressed in future production versions.

Area	Detail
GPS indoors	Neo-6M signal degrades inside buildings. Dashboard retains last known location.
DHT11 accuracy	±2 °C — suitable for prototypes. Production should use DHT22 or SHT31.
Single firefighter	Firmware hardcoded for device ID `FF_001`. Multi-device support is planned.
Firebase auth	Uses legacy Database Secret. Should use Firebase Auth tokens in production.
SSL verification	`client.setInsecure()` disables cert verification. Production must verify the server cert.
Timestamp	ESP32 sends `millis()` (uptime), not wall-clock time. Dashboard uses server local time.
Connectivity	Wi-Fi range ~50–100 m indoors. LoRa / GSM upgrades planned for larger deployments.

Project Team

Team

The people behind the Sustainable Firefighter Monitoring Device project.

Srinivasa Manikanta

Developer who handled the entire software side of the project, including system logic, integration, and dashboard development.

Santhosh

Engineer who took care of the presentation work and also contributed to the hardware connections for the project.

Sri Chaitanya

Engineer who took care of the hardware connections and supported the physical implementation of the project.

Sustainable FirefighterMonitoring Device

What is SFMD?

System Architecture

Data Payload (ESP32 → Firebase)

Hardware Components

Pin Map — ESP32

How It Works

Device States

Movement Detection — No-Motion Timer

Temperature Thresholds

SOS Button Logic

Web Dashboard

Project Gallery

Technologies Used

Firmware (ESP32)

Web Dashboard

API Endpoints

Assumptions & Known Limitations

Team

Sustainable Firefighter
Monitoring Device