Smart Bridge Monitoring System

An intelligent IoT-based bridge safety monitoring system using ESP32, designed to detect earthquakes, floods, and structural vibrations to ensure public safety through automated gate controls and real-time alerts.

Project Overview

This system continuously monitors bridge conditions using vibration and water level sensors, automatically controlling entry/exit gates based on detected hazards. All data is logged to Supabase for remote monitoring and historical analysis.

Key Features

• Real-time Vibration Detection using SW1801P analog sensor
• Flood Detection with water level monitoring
• Automated Gate Control with servo motors
• Multi-level Alert System (Visual, Audio, Remote)
• Cloud Data Logging via Supabase integration
• MQTT Communication for remote control
• LCD Status Display for local monitoring

System Architecture

[Sensors] → [ESP32] → [Local Actions] → [Cloud Storage]
    ↓         ↓           ↓              ↓
Vibration   Process    Gate Control   Supabase DB
Water Level  Data      LED/Buzzer     MQTT Broker

Hardware Components

Component	Model	Purpose	Pin
Microcontroller	ESP32	Main processing unit	-
Vibration Sensor	SW1801P	Earthquake/vibration detection	Pin 34
Water Sensor	Generic	Flood detection	Pin 25
Servo Motors	SG90 (x2)	Gate control	Pins 32, 33
LCD Display	16x2 I2C	Status display	I2C
LED	Generic	Visual alert	Pin 14
Buzzer	Active	Audio alert	Pin 27

System States

State	Vibration Level	Actions	Gates	Alerts
Normal	0-29	Normal operation	Open	None
Minor Vibration	30-99	Monitor closely	Open	Slow LED blink
Major Vibration	100-199	Caution mode	Partial close	Fast LED + intermittent buzzer
Earthquake	200+	Emergency shutdown	Entry closed, Exit open	Continuous LED + rapid buzzer
Flood	Water > threshold	Emergency shutdown	Entry closed, Exit open	Continuous LED + buzzer

🚀 Quick Start

Prerequisites

• Arduino IDE with ESP32 board support
• Required libraries (see Installation section)
• WiFi network access
• Supabase account
• HiveMQ Cloud account (or MQTT broker)

Installation

1. Clone the repository:

   git clone https://github.com/yourusername/smart-bridge-monitoring](https://github.com/Mariam-coder7/Safety-.git
   cd smart-bridge-monitoring

2. Install required Arduino libraries:

   ESP32Servo
   LiquidCrystal_I2C
   WiFi
   PubSubClient
   WiFiClientSecure
   HTTPClient
   ArduinoJson
   

3. Configure credentials:

   // WiFi Settings
   const char* ssid = "YOUR_WIFI_SSID";
   const char* password = "YOUR_WIFI_PASSWORD";
   
   // MQTT Settings
   const char* mqtt_server = "YOUR_MQTT_BROKER";
   const char* mqtt_user = "YOUR_MQTT_USER";
   const char* mqtt_pass = "YOUR_MQTT_PASS";
   
   // Supabase Settings
   const char* supabase_url = "https://fvlptjzaleesanbusaoi.supabase.co";
   const char* supabase_key = "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJzdXBhYmFzZSIsInJlZiI6ImZ2bHB0anphbGVlc2FuYnVzYW9pIiwicm9sZSI6ImFub24iLCJpYXQiOjE3NTY0NzM0MzQsImV4cCI6MjA3MjA0OTQzNH0.d3XDPnlOiiDnr3v2IHiy5QBpKKauKP5HNcRVWmjyKtw";

4. Upload to ESP32:

   • Connect ESP32 via USB
   • Select board and port in Arduino IDE
   • Upload the sketch

sensor_readings

CREATE TABLE sensor_readings (
    id SERIAL PRIMARY KEY,
    vibration_level INTEGER,
    max_vibration INTEGER,
    water_level INTEGER,
    system_state TEXT,
    alert_message TEXT,
    timestamp TIMESTAMPTZ DEFAULT NOW()
);

gate_operations

CREATE TABLE gate_operations (
    id SERIAL PRIMARY KEY,
    gate_number INTEGER,
    action TEXT,
    status TEXT,
    trigger_reason TEXT,
    timestamp TIMESTAMPTZ DEFAULT NOW()
);

system_alerts

CREATE TABLE system_alerts (
    id SERIAL PRIMARY KEY,
    alert_type TEXT,
    severity TEXT,
    message TEXT,
    timestamp TIMESTAMPTZ DEFAULT NOW()
);

MQTT Topics

Topic	Purpose	Message Format
bridge/sensor/vibration	Vibration readings	Integer (0-1000+)
bridge/sensor/water	Water level readings	Integer (0-4095)
bridge/alerts	System alerts	String message
bridge/gates/gate1/cmd	Gate 1 commands	"OPEN" / "CLOSE"
bridge/gates/gate1/status	Gate 1 status	"open" / "closed"
bridge/gates/gate2/cmd	Gate 2 commands	"OPEN" / "CLOSE"
bridge/gates/gate2/status	Gate 2 status	"open" / "closed"

Configuration

Sensor Calibration

• System automatically calibrates vibration sensor on startup
• Requires 5-10 seconds of no movement during initialization
• Baseline value stored for accurate vibration detection

Threshold Adjustment

const int minorVibThreshold = 30;     // Adjust for sensitivity
const int majorVibThreshold = 100;    // Adjust for local conditions
const int earthquakeThreshold = 200;  // Critical level threshold
int waterThreshold = 500;             // Flood detection level

Data Flow

1. Sensor Reading (Every 50ms)

   • Vibration sensor: Analog reading processed against baseline
   • Water sensor: Analog reading compared to threshold

2. State Processing (Continuous)

   • Analyze sensor data
   • Determine appropriate system state
   • Execute state-specific actions

3. Data Logging (Every 30 seconds)

   • Send sensor readings to Supabase
   • Publish MQTT messages
   • Log gate operations and alerts

4. Emergency Response (Immediate)

   • Critical alerts sent instantly to Supabase
   • Gate operations logged with reason
   • MQTT emergency broadcasts

🎛️ Remote Control

MQTT Commands

# Open/Close Gate 1
mosquitto_pub -h YOUR_BROKER -u USER -P PASS -t "bridge/gates/gate1/cmd" -m "OPEN"
mosquitto_pub -h YOUR_BROKER -u USER -P PASS -t "bridge/gates/gate1/cmd" -m "CLOSE"

# Open/Close Gate 2  
mosquitto_pub -h YOUR_BROKER -u USER -P PASS -t "bridge/gates/gate2/cmd" -m "OPEN"
mosquitto_pub -h YOUR_BROKER -u USER -P PASS -t "bridge/gates/gate2/cmd" -m "CLOSE"

Note: Manual commands are rejected during emergency states for safety.

🔍 Monitoring & Analytics

Real-time Monitoring

• Local LCD display for on-site status

Data Analysis Queries

-- Recent vibration patterns
SELECT vibration_level, max_vibration, timestamp 
FROM sensor_readings 
WHERE timestamp > NOW() - INTERVAL '1 hour'
ORDER BY timestamp DESC;

-- Emergency events
SELECT alert_type, severity, message, timestamp 
FROM system_alerts 
WHERE severity = 'CRITICAL'
ORDER BY timestamp DESC;

-- Gate operation history
SELECT gate_number, action, trigger_reason, timestamp 
FROM gate_operations 
ORDER BY timestamp DESC;

🛡 Safety Features

• Fail-Safe Design: Emergency states override manual commands
• Redundant Monitoring: Both current and peak vibration levels checked
• Evacuation Protocol: Exit gates open during emergencies
• Data Persistence: All events logged for analysis
• Remote Monitoring: Cloud-based oversight capability

🔧 Troubleshooting

Common Issues

WiFi Connection Failed

• Check SSID and password
• Ensure 2.4GHz network (ESP32 doesn't support 5GHz)
• Verify signal strength

MQTT Connection Issues

• Verify broker credentials and URL
• Check network connectivity
• Ensure SSL/TLS settings match broker requirements

Sensor Calibration Problems

• Keep system still during startup calibration
• Check sensor wiring and connections
• Verify 3.3V power supply to sensors

Supabase Upload Errors

• Verify Supabase URL and API key
• Check table schemas match code
• Ensure RLS policies allow insertions

Future Enhancements

• Machine learning for predictive maintenance
• Mobile app for remote monitoring
• Integration with emergency services
• Multi-bridge network management
• Weather data integration
• Camera-based visual monitoring

Contributing

1. Fork the repository
2. Create your feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request : [your-email@example.com]

Acknowledgments

• ESP32 community for excellent documentation
• Supabase team for robust backend services
• Arduino ecosystem for simplified IoT development
• Open source sensor libraries and examples

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⚠️ Safety Notice: This system is designed for monitoring and alerting purposes. Always follow local safety regulations and have professional structural engineers assess bridge safety concerns.